This document describes the development of a fluorescent probe for sensing thiamine (vitamin B1) based on arginine-functionalized graphene quantum dots (Arg-GQDs). Arg-GQDs were synthesized through a one-pot hydrothermal method using citric acid and arginine as carbon and nitrogen precursors. The Arg-GQDs exhibited strong blue fluorescence with a quantum yield of 28.3%. The fluorescence of the Arg-GQDs was selectively quenched by Ag+ ions and recovered upon addition of thiamine, providing the basis for a fluorescence "off-on" probe for thiamine. Central composite design and response surface methodology were used to optimize the detection conditions, including pH, time
Novel composite electrodes:Preparation and application to the electroanalytic...Université de Dschang
M. Tchieno Melataguia Francis Merlin a soutenu une thèse de Doctorat/Phd en Chimie Inorganique ce 06 juin 2016 dans la salle des conférences de l'Université de Dschang. A l'issue de cette soutenance devant le jury présidé par le Prof. Emmanuel Ngameni lui a décerné la mention très honorable à l'unanimité de ses membres.
A facile and efficient synthesis of some odorant Schiff bases using microwave...Pawan Kumar
Three odorant Schiff bases of methylanthranilate, an aroma constituent of blossom essential oils, with naturally occurring
odorant aldehydes- anisaldehyde, benzaldehyde and cinnamaldehyde employing microwave (MW) irradiation method were
synthesized. Elemental and spectral (FT-IR, 1H-NMR) analysis of these compounds supported their molecular structures.
Olfactory properties of these Schiff bases indicated their suitability for use in various fragrance compositions. These
compounds also showed varied antimicrobial activity against Aspergillus niger, Penicillium chrysogenum, Staphylococcus
aureus and Escherichia coli.
Physical and Structural Characterization of Biofield Treated Imidazole Deriva...albertdivis
The Aim of present study was to evaluate the impact of biofield treatment on two imidazole derivatives (i.e., imidazole and 2-methylimidazole) by various analytical methods.
Physicochemical and Spectroscopic Characterization of Biofield Energy Treated...rachelsalk
The p-anisidine is widely used as chemical intermediate in the production of various dyes, pigments, and pharmaceuticals. This study was aimed to evaluate the effect of biofield energy treatment on the physicochemical and spectroscopic properties of p-anisidine. The study was performed after dividing the sample in two groups; one was remained as untreated and another was subjected to Mr. Trivedi’s biofield energy treatment. Afterward, both the control and treated samples of p-anisidine were evaluated using X-ray diffraction (XRD), surface area analyzer, differential scanning calorimetry (DSC), thermogravimetric analysis-derivative thermogravimetry (TGA-DTG), Fourier transform infrared (FT-IR), and ultraviolet-visible (UV-Vis) spectroscopy. The XRD analysis showed the increase in unit cell volume from 683.81 → 690.18 × 10-24 cm3 and crystallite size from 83.84→84.62 nm in the treated sample with respect to the control. The surface area analysis exhibited the significant increase (25.44%) in the surface area of treated sample as compared to control. The DSC thermogram of control p-anisidine showed the latent heat of fusion and melting temperature and 146.78 J/g and 59.41°C, respectively, which were slightly increased to 148.89 J/g and 59.49°C, respectively after biofield treatment. The TGA analysis showed the onset temperature of thermal degradation at 134.68°C in the control sample that was increased to 150.02°C after biofield treatment. The result showed about 11.39% increase in onset temperature of thermal degradation of treated p-anisidine as compared to the control. Moreover, the Tmax (temperature at which maximum thermal degradation occurs) was also increased slightly from 165.99°C (control) to 168.10°C (treated). This indicated the high thermal stability of treated p-anisidine as compared to the control. However, the FT-IR and UV spectroscopic studies did not show any significant changes in the spectral properties of treated p-anisidine with respect to the control.
Novel composite electrodes:Preparation and application to the electroanalytic...Université de Dschang
M. Tchieno Melataguia Francis Merlin a soutenu une thèse de Doctorat/Phd en Chimie Inorganique ce 06 juin 2016 dans la salle des conférences de l'Université de Dschang. A l'issue de cette soutenance devant le jury présidé par le Prof. Emmanuel Ngameni lui a décerné la mention très honorable à l'unanimité de ses membres.
A facile and efficient synthesis of some odorant Schiff bases using microwave...Pawan Kumar
Three odorant Schiff bases of methylanthranilate, an aroma constituent of blossom essential oils, with naturally occurring
odorant aldehydes- anisaldehyde, benzaldehyde and cinnamaldehyde employing microwave (MW) irradiation method were
synthesized. Elemental and spectral (FT-IR, 1H-NMR) analysis of these compounds supported their molecular structures.
Olfactory properties of these Schiff bases indicated their suitability for use in various fragrance compositions. These
compounds also showed varied antimicrobial activity against Aspergillus niger, Penicillium chrysogenum, Staphylococcus
aureus and Escherichia coli.
Physical and Structural Characterization of Biofield Treated Imidazole Deriva...albertdivis
The Aim of present study was to evaluate the impact of biofield treatment on two imidazole derivatives (i.e., imidazole and 2-methylimidazole) by various analytical methods.
Physicochemical and Spectroscopic Characterization of Biofield Energy Treated...rachelsalk
The p-anisidine is widely used as chemical intermediate in the production of various dyes, pigments, and pharmaceuticals. This study was aimed to evaluate the effect of biofield energy treatment on the physicochemical and spectroscopic properties of p-anisidine. The study was performed after dividing the sample in two groups; one was remained as untreated and another was subjected to Mr. Trivedi’s biofield energy treatment. Afterward, both the control and treated samples of p-anisidine were evaluated using X-ray diffraction (XRD), surface area analyzer, differential scanning calorimetry (DSC), thermogravimetric analysis-derivative thermogravimetry (TGA-DTG), Fourier transform infrared (FT-IR), and ultraviolet-visible (UV-Vis) spectroscopy. The XRD analysis showed the increase in unit cell volume from 683.81 → 690.18 × 10-24 cm3 and crystallite size from 83.84→84.62 nm in the treated sample with respect to the control. The surface area analysis exhibited the significant increase (25.44%) in the surface area of treated sample as compared to control. The DSC thermogram of control p-anisidine showed the latent heat of fusion and melting temperature and 146.78 J/g and 59.41°C, respectively, which were slightly increased to 148.89 J/g and 59.49°C, respectively after biofield treatment. The TGA analysis showed the onset temperature of thermal degradation at 134.68°C in the control sample that was increased to 150.02°C after biofield treatment. The result showed about 11.39% increase in onset temperature of thermal degradation of treated p-anisidine as compared to the control. Moreover, the Tmax (temperature at which maximum thermal degradation occurs) was also increased slightly from 165.99°C (control) to 168.10°C (treated). This indicated the high thermal stability of treated p-anisidine as compared to the control. However, the FT-IR and UV spectroscopic studies did not show any significant changes in the spectral properties of treated p-anisidine with respect to the control.
Degradation of Paracetamol by Electro-Fenton and Photoelectro-Fenton Processe...Oswar Mungkasa
prepared by M.C. Lu *, M.L.Veciana**, M.D.G. de Luna*** * Department of Environmental Resources Management, Chia Nan University of Pharmacy and Science, Tainan 717, Taiwan **Environmental Engineering Graduate Program, University of the Philippines, 1011 Diliman, Quezon City, Philippines *** Department of Chemical Engineering, University of the Philippines, 1011 Diliman, Quezon City, Phi for Urban Environments in Asia, 25-28 May 2011, Manila, Philippines. organized by International Water Association (IWA).
Thermodynamics and adsorption studies of rhodamine-b dye onto organoclayInnspub Net
Thermodynamics and adsorption studies were conducted with a dye of Rhoda mine-B (RB) on organoclay (OC). Adsorption of the dye was investigated with an initial dye concentration at pH 7±0.3, 298, 308 and 318 K. The adsorption experiments were carried out isothermally at three different temperatures. The Langmuir and Freundlich isotherm models were used to describe the equilibrium data and the results were discussed in details. The thermodynamic parameters such as standard free energy (∆G°), entropy change (∆S°) and enthalpy (∆H°) were calculated for OC. These values showed that adsorption of RB on OC was a spontaneous and endothermic process.
Experimental and Theoretical Studies of Heat Transfer in Graphene/Agar under ...CrimsonPublishersRDMS
Experimental and Theoretical Studies of Heat Transfer in Graphene/Agar under Laser Irradiation by Siheng Su * in Crimson Publishers: Peer Reviewed Material Science Journals
Speciation And Physicochemical Studies of Some Biospecific CompoundsIOSR Journals
Abstract: A green, safer , efficient , eco-friendly approach for the synthesis of novel compounds which reveal biological and spermicidal activity. The nature of the pharmacophore decides the physiological reactivity of the compound.
Physicochemical Properties and Proposed Mechanism in the Obtainment of 4-Hidr...IJERA Editor
The mechanism for the poly-condensation event of conjugated polymers with ending 4-hydroxycoumarin has
been proposed. It happened under H2SO4 acidic conditions only using enolic-coumarins without any substituent
at third position. It was studied using Matrix assisted laser desorption/ionization time-of-flight (MALDI-Tof)
mass spectrometry. Besides, some physicochemical properties were analyzed using Thermo-gravimetric (TGA),
X-ray and UV-Vis analysis
Multi-Element Determination of Cu, Mn, and Se using Electrothermal Atomic Abs...IOSR Journals
Simultaneous multi-element graphite furnace atomic absorption spectrometer (SIMAA 6000) is used to get a new multi-element determinations methodology for Cu, Mn, and Se. Firstly, the optimum conditions for single-element mode are determined (which include: pyrolysis and atomization temperatures). Secondly, the optimum conditions for multi-element mode are also determined. The conditions in the two modes have been compared in terms of the characteristic masses, detection limits and pyrolysis and atomization temperatures. The effect of the matrix on the determination has been studied using urine standard sample from Seronorm (LOT 0511545). The accuracy of the developing methods has been confirmed by analysis different biological reference materials. Simultaneous multi-element GF-AAS offers a rapid, low cost and sensitive method for the analysis of trace elements
Biofield Treatment: A Potential Strategy for Modification of Physical and The...albertdivis
Indole compounds are important class of therapeutic molecules, which have excellent pharmaceutical applications. The objective of present research was to investigate the influence of biofield treatment on physical and thermal properties of indole.
FIBER OPTIC AIDED SPECTROPHOTOMETRIC DETERMINATION OF GADOLINIUM IN FBR REPRO...ijac123
A new spectrophotometric method has been developed for the quantitative analysis of gadolinium using 1,2-dihydroxy anthraquinone-3-sulphonic acid, sodium salt (Alizarin Red S). Influence of various parameters such as concentration of complexing agent, pH, and interference of other competing metal ions was examined in a systematic manner.
Flame Photometric Estimation of Sodium and Potassium
Ion Present In Water Sample of Darna and Godavari
River...
• Flame Photometry also known as flame atomic emission spectrometry is a branch of analytical science that examined the species in form of an atom, mostly it works on the principle of ionization of alkali metal salt drawn into a non-luminous flame
• Alkali metal salt absorbs energy from flame and emits the light of a characteristic wavelength which is observed by the change in intensity of color, the energy absorbed was enough to vaporize alkali metal salt.
• In the present article the comparative studies on sodium and potassium content present in a water sample collected from Darna and Godavari River were calculated.
This Presentation Contains the following...
#Information about Paper
#Abstract
#Materials
#Method
#Characteristic Wavelengths of The Elements
#Procedure
#Result and Discussion
#Conclusion
#References
Thanks for the Help and Guidance of Dr. P. B. Choudhari (Assistant Professor, Pharmaceutical Chemistry) and Mr. V. A. Thorat (Assistant Professor, Department of Pharmacognosy) of Bharati Vidyapeeth College of Pharmacy, Kolhapur.
ER Publication,
IJETR, IJMCTR,
Journals,
International Journals,
High Impact Journals,
Monthly Journal,
Good quality Journals,
Research,
Research Papers,
Research Article,
Free Journals, Open access Journals,
erpublication.org,
Engineering Journal,
Science Journals,
Studies on Biofield Treated p-Dichlorobenzene | Omicsonlinedeeptimishra10
The aim of present study was to evaluate the impact of biofield energy treatment on physical, thermal, and spectroscopic properties of p-dichlorobenzene.
Antibacterial Application of Novel Mixed-Ligand Dithiocarbamate Complexes of ...IOSR Journals
Nine stable mixed ligand dithiocarbamate complexes of Nickel (II) ion were prepared. The complexes were characterized with electronic spectroscopy, infrared spectroscopy, conductance measurement, melting point and percentage metal analysis. Resulting analytical data gave credence to the assignment of a tentative square planar geometry to all the complexes. The complexes were proposed to have a general formulae of [Ni(Sal)(Rdtc)], where Sal = salicylaldehyde; R = dibenzylamine(Bz2NH), methylphenylamine(MePhNH),pyrrolidineamine(pyrrolNH),piperidineamine(piperNH),morpholineamine(MorpNH), anilineamine(AnilNH), para-chloroanilineamine(p-ClAnilNH), toludineamine(TolNH) and anisidineamine(AnisNH); and dtc = dithiocarbamate anion. The metal complexes were screened against six different bacteria strain using Agar diffusion method. The antibacterial studies reveal that the metal complexes exhibit broad spectrum antibacterial activity against Escherichia coli, Staphylococcus aureus, Klebsiella oxytoca and Pseudomonas aureginosa with inhibitory range of 10.5.—20.0mm.
Quantitative Analysis of 30 Drugs in Whole Blood by SPE and UHPLC-TOF-MSAnnex Publishers
Abstract
An Ultra-High Pressure Liquid Chromatography Time-of-Flight Mass Spectrometry (UHPLC-TOF-MS) method for quantitative analysis of 30 drugs in whole blood was developed and validated. The method was used for screening and quantification of common drugs and drugs of abuse in whole blood received from autopsy cases and living persons. The compounds included: alprazolam, amphetamine, benzoylecgonine, bromazepam, cathine, cathinone, chlordiazepoxide, cocaine, codeine, clonazepam, 7-aminoclonazepam, diazepam, nordiazepam, flunitrazepam, 7-aminoflunitrazepam, ketamine, ketobemidone, 3,4-Methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), methamphetamine, methadone, morphine, 6-monoacetylmorphine, nitrazepam, 7-aminonitrazepam, oxazepam, temazepam, tramadol, O-desmethyltramadol, and zolpidem. Blood samples (200 μL) were subjected to Solid Phase Extraction (SPE). Target drugs were quantified using a Waters ACQUITY UPLC system coupled to a Waters SYNAPT G2 TOF-MS apparatus. Extraction recoveries ranged from 41% (7-aminoclonazepam) to 111% (ketamine) and matrix effects ranged from -13% (temazepam) to 50% (7-aminonitrazepam). For all compounds, a quadratic polynomial was applied for fitting the calibration curves. Lower Limits of Quantification (LOQ) ranged from 0.005 to 0.05 mg/kg. Satisfactory precisions below 15% and accuracies within 85-115% were obtained for all compounds at concentrations exceeding the LOQ. In conclusion, we present a validated UHPLC-TOF-MS method for simultaneous quantification of 30 drugs in whole blood with a run time of 15 min using 200 μL of whole blood.
Keywords: Drugs of abuse, UHPLC-TOF-MS, Whole blood, SPE, Quantification
Toxicity immobilization of refinery sludge containing heavy metals via vitrif...eSAT Journals
Abstract Heavy metals are known to be toxic to human and the environment. Despite the growing of petrochemical and refinery industries, the world is facing problems with the heavy metals contamination from the sludge by the industries. Many methods have been applied to address these issues from the refinery sludge. In this study, stabilization and solidification of refinery sludge containing heavy metals using vitrification method was utilized to solve this problem. The ashing temperature of 550oC was selected in preparing the ash of the dried sludge prior to the vitrification process at 1110oC to 1400oC. After vitrification, all samples were morphologically, thermally and toxically analyzed using Scanning Electron Microscopy, Thermogravimetric Analysis and Toxicity Characteristic Leaching Procedure. The sludge contained high amount of iron and aluminum, followed by some amount of magnesium, gold, arsenic and zinc with some traces of nickel and lead. Results showed that at maximum vitrified temperature of 1400oC, no magnesium, nickel and lead were detected in the sludge and only some traces of other heavy metals with less than 1 ppm. The vitrification method exhibits excellent output in immobilizing the transition metals leading to a reduction in environmental pollution caused by petrochemical and refinery sludge containing heavy metals. Index Terms: Vitrification, Heavy metals contamination, Refinery sludge, Toxicity, Leaching analysis
New Schiff base ligand (E)-6-(2-(4-
(dimethylamino)benzylideneamino)-2-phenylacetamido)-3,3-
dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic
acid = (HL) Figure(1) was prepared via condensation of
Ampicillin and 4(dimethylamino)benzaldehyde in methanol
.Polydentate mixed ligand complexes were obtained from 1:1:2
molar ratio reactions with metal ions and HL, 2NA on reaction
with MCl2 .nH2O salt yields complexes corresponding to the
formulas [M(L)(NA)2Cl] ,where M =
Fe(II),Co(II),Ni(II),Cu(II),and Zn(II) and NA=nicotinamide.
The 1H-NMR, FT-IR, UV-Vis and elemental analysis
were used for the characterization of the ligand. The complexes
were structurally studied through AAS, FT-IR, UV-Vis,
chloride contents, conductance, and magnetic susceptibility
measurements. All complexes are non-electrolytes in DMSO
solution. Octahedral geometries have been suggested for each
of the complexes. The Schiff base ligands function as
tridentates and the deprotonated enolic form is preferred for
coordination. In order to evaluate the effect of the bactericidal
activity, these synthesized complexes, in comparison to the un
complexed Schiff base has been screened against bacterial
species, Staphy
Simultaneous voltammetric determination of paracetamol anddomperidone based o...Pramod Kalambate
Graphene oxide and hexachloroplatinic acid were electrochemically reduced on a glassy carbon elec-trode (GCE) surface so as to form a graphene (Gr)–platinum nanoparticles (PtNP) composite. This nanocomposite was then coated with nafion (NAF) film so as to form NAF/PtNP/Gr/GCE. In this work, anelectrochemical method based on adsorptive stripping square wave voltammetry (AdSSWV) employ-ing NAF/PtNP/Gr/GCE has been proposed for the subnanomolar determination of paracetamol (PCT) anddomperidone (DOM) simultaneously. The electrode material was characterized by scanning electronmicroscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The electrochemical perfor-mance of PCT and DOM on modified electrode was investigated by cyclic voltammetry, electrochemicalimpedance spectroscopy, and chronocoulometry. A sixteen fold enhancement in the AdSSWV signal wasobserved at NAF/PtNP/Gr/GCE in pH 6.0, phosphate buffer, as compared to GCE. Under the optimized con-ditions, the method allowed simultaneous determination of PCT and DOM in the linear working range of8.2 × 10−6–1.6 × 10−9M with detection limits (3 × SD/s) of 1.06 × 10−10and 4.37 × 10−10M for PCT andDOM respectively. The practical analytical utilities of the modified electrode were demonstrated by thedetermination of PCT and DOM in pharmaceutical formulations, human urine, and blood serum samples.This proposed method was validated by HPLC and the results are in agreement at the 95% confidencelevel. Simultaneous voltammetric determination of PCT and DOM has been reported for the first time.
Determination of Riociguat by Oxidative Coupling Using Visible SpectrophotometryRatnakaram Venkata Nadh
A simple spectrophotometric method was developed to determine riociguat in bulk and tablet formulation. The present method lies on the oxidation of MBTH by Fe+3 ions in acidic medium to form active coupling species and followed by its coupling with riociguat to form the chromophore having lmax 660 nm. Validated the proposed method as per the existing guidelines of ICH. Good linearity (r~ 0.999) was observed for calibration curve in the studied concentration range (6.25 – 37.50 μg mL-1). Reproducibility, accuracy and precision of the method were confirmed from low values of % RSD.
Degradation of Paracetamol by Electro-Fenton and Photoelectro-Fenton Processe...Oswar Mungkasa
prepared by M.C. Lu *, M.L.Veciana**, M.D.G. de Luna*** * Department of Environmental Resources Management, Chia Nan University of Pharmacy and Science, Tainan 717, Taiwan **Environmental Engineering Graduate Program, University of the Philippines, 1011 Diliman, Quezon City, Philippines *** Department of Chemical Engineering, University of the Philippines, 1011 Diliman, Quezon City, Phi for Urban Environments in Asia, 25-28 May 2011, Manila, Philippines. organized by International Water Association (IWA).
Thermodynamics and adsorption studies of rhodamine-b dye onto organoclayInnspub Net
Thermodynamics and adsorption studies were conducted with a dye of Rhoda mine-B (RB) on organoclay (OC). Adsorption of the dye was investigated with an initial dye concentration at pH 7±0.3, 298, 308 and 318 K. The adsorption experiments were carried out isothermally at three different temperatures. The Langmuir and Freundlich isotherm models were used to describe the equilibrium data and the results were discussed in details. The thermodynamic parameters such as standard free energy (∆G°), entropy change (∆S°) and enthalpy (∆H°) were calculated for OC. These values showed that adsorption of RB on OC was a spontaneous and endothermic process.
Experimental and Theoretical Studies of Heat Transfer in Graphene/Agar under ...CrimsonPublishersRDMS
Experimental and Theoretical Studies of Heat Transfer in Graphene/Agar under Laser Irradiation by Siheng Su * in Crimson Publishers: Peer Reviewed Material Science Journals
Speciation And Physicochemical Studies of Some Biospecific CompoundsIOSR Journals
Abstract: A green, safer , efficient , eco-friendly approach for the synthesis of novel compounds which reveal biological and spermicidal activity. The nature of the pharmacophore decides the physiological reactivity of the compound.
Physicochemical Properties and Proposed Mechanism in the Obtainment of 4-Hidr...IJERA Editor
The mechanism for the poly-condensation event of conjugated polymers with ending 4-hydroxycoumarin has
been proposed. It happened under H2SO4 acidic conditions only using enolic-coumarins without any substituent
at third position. It was studied using Matrix assisted laser desorption/ionization time-of-flight (MALDI-Tof)
mass spectrometry. Besides, some physicochemical properties were analyzed using Thermo-gravimetric (TGA),
X-ray and UV-Vis analysis
Multi-Element Determination of Cu, Mn, and Se using Electrothermal Atomic Abs...IOSR Journals
Simultaneous multi-element graphite furnace atomic absorption spectrometer (SIMAA 6000) is used to get a new multi-element determinations methodology for Cu, Mn, and Se. Firstly, the optimum conditions for single-element mode are determined (which include: pyrolysis and atomization temperatures). Secondly, the optimum conditions for multi-element mode are also determined. The conditions in the two modes have been compared in terms of the characteristic masses, detection limits and pyrolysis and atomization temperatures. The effect of the matrix on the determination has been studied using urine standard sample from Seronorm (LOT 0511545). The accuracy of the developing methods has been confirmed by analysis different biological reference materials. Simultaneous multi-element GF-AAS offers a rapid, low cost and sensitive method for the analysis of trace elements
Biofield Treatment: A Potential Strategy for Modification of Physical and The...albertdivis
Indole compounds are important class of therapeutic molecules, which have excellent pharmaceutical applications. The objective of present research was to investigate the influence of biofield treatment on physical and thermal properties of indole.
FIBER OPTIC AIDED SPECTROPHOTOMETRIC DETERMINATION OF GADOLINIUM IN FBR REPRO...ijac123
A new spectrophotometric method has been developed for the quantitative analysis of gadolinium using 1,2-dihydroxy anthraquinone-3-sulphonic acid, sodium salt (Alizarin Red S). Influence of various parameters such as concentration of complexing agent, pH, and interference of other competing metal ions was examined in a systematic manner.
Flame Photometric Estimation of Sodium and Potassium
Ion Present In Water Sample of Darna and Godavari
River...
• Flame Photometry also known as flame atomic emission spectrometry is a branch of analytical science that examined the species in form of an atom, mostly it works on the principle of ionization of alkali metal salt drawn into a non-luminous flame
• Alkali metal salt absorbs energy from flame and emits the light of a characteristic wavelength which is observed by the change in intensity of color, the energy absorbed was enough to vaporize alkali metal salt.
• In the present article the comparative studies on sodium and potassium content present in a water sample collected from Darna and Godavari River were calculated.
This Presentation Contains the following...
#Information about Paper
#Abstract
#Materials
#Method
#Characteristic Wavelengths of The Elements
#Procedure
#Result and Discussion
#Conclusion
#References
Thanks for the Help and Guidance of Dr. P. B. Choudhari (Assistant Professor, Pharmaceutical Chemistry) and Mr. V. A. Thorat (Assistant Professor, Department of Pharmacognosy) of Bharati Vidyapeeth College of Pharmacy, Kolhapur.
ER Publication,
IJETR, IJMCTR,
Journals,
International Journals,
High Impact Journals,
Monthly Journal,
Good quality Journals,
Research,
Research Papers,
Research Article,
Free Journals, Open access Journals,
erpublication.org,
Engineering Journal,
Science Journals,
Studies on Biofield Treated p-Dichlorobenzene | Omicsonlinedeeptimishra10
The aim of present study was to evaluate the impact of biofield energy treatment on physical, thermal, and spectroscopic properties of p-dichlorobenzene.
Antibacterial Application of Novel Mixed-Ligand Dithiocarbamate Complexes of ...IOSR Journals
Nine stable mixed ligand dithiocarbamate complexes of Nickel (II) ion were prepared. The complexes were characterized with electronic spectroscopy, infrared spectroscopy, conductance measurement, melting point and percentage metal analysis. Resulting analytical data gave credence to the assignment of a tentative square planar geometry to all the complexes. The complexes were proposed to have a general formulae of [Ni(Sal)(Rdtc)], where Sal = salicylaldehyde; R = dibenzylamine(Bz2NH), methylphenylamine(MePhNH),pyrrolidineamine(pyrrolNH),piperidineamine(piperNH),morpholineamine(MorpNH), anilineamine(AnilNH), para-chloroanilineamine(p-ClAnilNH), toludineamine(TolNH) and anisidineamine(AnisNH); and dtc = dithiocarbamate anion. The metal complexes were screened against six different bacteria strain using Agar diffusion method. The antibacterial studies reveal that the metal complexes exhibit broad spectrum antibacterial activity against Escherichia coli, Staphylococcus aureus, Klebsiella oxytoca and Pseudomonas aureginosa with inhibitory range of 10.5.—20.0mm.
Quantitative Analysis of 30 Drugs in Whole Blood by SPE and UHPLC-TOF-MSAnnex Publishers
Abstract
An Ultra-High Pressure Liquid Chromatography Time-of-Flight Mass Spectrometry (UHPLC-TOF-MS) method for quantitative analysis of 30 drugs in whole blood was developed and validated. The method was used for screening and quantification of common drugs and drugs of abuse in whole blood received from autopsy cases and living persons. The compounds included: alprazolam, amphetamine, benzoylecgonine, bromazepam, cathine, cathinone, chlordiazepoxide, cocaine, codeine, clonazepam, 7-aminoclonazepam, diazepam, nordiazepam, flunitrazepam, 7-aminoflunitrazepam, ketamine, ketobemidone, 3,4-Methylenedioxyamphetamine (MDA), 3,4-methylenedioxymethamphetamine (MDMA), methamphetamine, methadone, morphine, 6-monoacetylmorphine, nitrazepam, 7-aminonitrazepam, oxazepam, temazepam, tramadol, O-desmethyltramadol, and zolpidem. Blood samples (200 μL) were subjected to Solid Phase Extraction (SPE). Target drugs were quantified using a Waters ACQUITY UPLC system coupled to a Waters SYNAPT G2 TOF-MS apparatus. Extraction recoveries ranged from 41% (7-aminoclonazepam) to 111% (ketamine) and matrix effects ranged from -13% (temazepam) to 50% (7-aminonitrazepam). For all compounds, a quadratic polynomial was applied for fitting the calibration curves. Lower Limits of Quantification (LOQ) ranged from 0.005 to 0.05 mg/kg. Satisfactory precisions below 15% and accuracies within 85-115% were obtained for all compounds at concentrations exceeding the LOQ. In conclusion, we present a validated UHPLC-TOF-MS method for simultaneous quantification of 30 drugs in whole blood with a run time of 15 min using 200 μL of whole blood.
Keywords: Drugs of abuse, UHPLC-TOF-MS, Whole blood, SPE, Quantification
Toxicity immobilization of refinery sludge containing heavy metals via vitrif...eSAT Journals
Abstract Heavy metals are known to be toxic to human and the environment. Despite the growing of petrochemical and refinery industries, the world is facing problems with the heavy metals contamination from the sludge by the industries. Many methods have been applied to address these issues from the refinery sludge. In this study, stabilization and solidification of refinery sludge containing heavy metals using vitrification method was utilized to solve this problem. The ashing temperature of 550oC was selected in preparing the ash of the dried sludge prior to the vitrification process at 1110oC to 1400oC. After vitrification, all samples were morphologically, thermally and toxically analyzed using Scanning Electron Microscopy, Thermogravimetric Analysis and Toxicity Characteristic Leaching Procedure. The sludge contained high amount of iron and aluminum, followed by some amount of magnesium, gold, arsenic and zinc with some traces of nickel and lead. Results showed that at maximum vitrified temperature of 1400oC, no magnesium, nickel and lead were detected in the sludge and only some traces of other heavy metals with less than 1 ppm. The vitrification method exhibits excellent output in immobilizing the transition metals leading to a reduction in environmental pollution caused by petrochemical and refinery sludge containing heavy metals. Index Terms: Vitrification, Heavy metals contamination, Refinery sludge, Toxicity, Leaching analysis
New Schiff base ligand (E)-6-(2-(4-
(dimethylamino)benzylideneamino)-2-phenylacetamido)-3,3-
dimethyl-7-oxo-4-thia-1-azabicyclo[3.2.0]heptane-2-carboxylic
acid = (HL) Figure(1) was prepared via condensation of
Ampicillin and 4(dimethylamino)benzaldehyde in methanol
.Polydentate mixed ligand complexes were obtained from 1:1:2
molar ratio reactions with metal ions and HL, 2NA on reaction
with MCl2 .nH2O salt yields complexes corresponding to the
formulas [M(L)(NA)2Cl] ,where M =
Fe(II),Co(II),Ni(II),Cu(II),and Zn(II) and NA=nicotinamide.
The 1H-NMR, FT-IR, UV-Vis and elemental analysis
were used for the characterization of the ligand. The complexes
were structurally studied through AAS, FT-IR, UV-Vis,
chloride contents, conductance, and magnetic susceptibility
measurements. All complexes are non-electrolytes in DMSO
solution. Octahedral geometries have been suggested for each
of the complexes. The Schiff base ligands function as
tridentates and the deprotonated enolic form is preferred for
coordination. In order to evaluate the effect of the bactericidal
activity, these synthesized complexes, in comparison to the un
complexed Schiff base has been screened against bacterial
species, Staphy
Simultaneous voltammetric determination of paracetamol anddomperidone based o...Pramod Kalambate
Graphene oxide and hexachloroplatinic acid were electrochemically reduced on a glassy carbon elec-trode (GCE) surface so as to form a graphene (Gr)–platinum nanoparticles (PtNP) composite. This nanocomposite was then coated with nafion (NAF) film so as to form NAF/PtNP/Gr/GCE. In this work, anelectrochemical method based on adsorptive stripping square wave voltammetry (AdSSWV) employ-ing NAF/PtNP/Gr/GCE has been proposed for the subnanomolar determination of paracetamol (PCT) anddomperidone (DOM) simultaneously. The electrode material was characterized by scanning electronmicroscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction. The electrochemical perfor-mance of PCT and DOM on modified electrode was investigated by cyclic voltammetry, electrochemicalimpedance spectroscopy, and chronocoulometry. A sixteen fold enhancement in the AdSSWV signal wasobserved at NAF/PtNP/Gr/GCE in pH 6.0, phosphate buffer, as compared to GCE. Under the optimized con-ditions, the method allowed simultaneous determination of PCT and DOM in the linear working range of8.2 × 10−6–1.6 × 10−9M with detection limits (3 × SD/s) of 1.06 × 10−10and 4.37 × 10−10M for PCT andDOM respectively. The practical analytical utilities of the modified electrode were demonstrated by thedetermination of PCT and DOM in pharmaceutical formulations, human urine, and blood serum samples.This proposed method was validated by HPLC and the results are in agreement at the 95% confidencelevel. Simultaneous voltammetric determination of PCT and DOM has been reported for the first time.
Determination of Riociguat by Oxidative Coupling Using Visible SpectrophotometryRatnakaram Venkata Nadh
A simple spectrophotometric method was developed to determine riociguat in bulk and tablet formulation. The present method lies on the oxidation of MBTH by Fe+3 ions in acidic medium to form active coupling species and followed by its coupling with riociguat to form the chromophore having lmax 660 nm. Validated the proposed method as per the existing guidelines of ICH. Good linearity (r~ 0.999) was observed for calibration curve in the studied concentration range (6.25 – 37.50 μg mL-1). Reproducibility, accuracy and precision of the method were confirmed from low values of % RSD.
Determination of Riociguat by Oxidative Coupling Using Visible SpectrophotometryRatnakaram Venkata Nadh
A simple spectrophotometric method was developed to determine riociguat in bulk and tablet formulation. The present method lies on the oxidation of MBTH by Fe+3 ions in acidic medium to form active coupling species and followed by its coupling with riociguat to form the chromophore having lmax 660 nm. Validated the proposed method as per the existing guidelines of ICH. Good linearity (r~ 0.999) was observed for calibration curve in the studied concentration range (6.25 – 37.50 μg mL-1). Reproducibility, accuracy and precision of the method were confirmed from low values of % RSD.
Toxic Trace Metals in Edible Oils by Graphite Furnace Atomic Absorption Spect...PerkinElmer, Inc.
"This method reports the development of a direct analysis
method for edible oil samples using GFAAS without digestion.
The advantages of using this method include small sample
volume, direct introduction of samples, high sensitivity, and
rapid analysis times. The application of GFAAS to arsenic,
lead and cadmium analysis in edible oils was performed.
The optimal pyrolysis and atomization temperatures, limit of detection, quality control (QC) checks and recoveries were studied in order to develop a rapid and accurate method.
Learn more about our solutions: http://bit.ly/1dqSYtg
Trace Elemental Characterization of Edible Oils with Graphite Furnace Atomic ...PerkinElmer, Inc.
This paper reports the development of a simple method for
the analysis of edible oil samples by using Graphite Furnace Atomic Absorption Spectrophotometer (GFAAS). Sample preparation has been done by using a microwave digestion system. Metals like Fe, Cu, Mn, Ni, Cr, As, Cd, Pb, Se and Zn were analyzed using the developed method.
Learn more about our solutions: http://bit.ly/1f7ZS7T
Au based nanomaterials (AuNMs) are known to possess many
attractive features such as unique electrical, optical and catalytic
properties as well as excellent biocompatibility. These outstanding
characteristics make them promising candidates as the signal reporters,
enhancement materials or others involved with bioassay, food safety
and environmental monitoring.
One Pot Hydrothermal Synthesis Characterizations Of Silver Nanoparticles On R...IOSRJAC
Graphene-based nanocomposite have significant applicability in catalysis, electronics, medicine, and energy. In this report silver nanoparticles (AgNPs) with Reduced Graphene Oxide (RGO) - nanocomposite was prepared by a one-pot hydrothermal process using silver nitrate as a precursor. Under hydrothermal process Graphene oxide (GO) was reduced to reduced graphene oxide (RGO), without using chemical reagents. As synthesized (Ag-RGO) nanocomposite was characterized by XRD, UV Vis-spectroscopy, Scanning electron microscope, and Raman spectroscopy. Antimicrobial activities of the composite were investigated against both Gram-positive and Gram-negative bacteria. The results demonstrate that Ag-RGO nanocomposite was a strong bactericide against Gram-negative bacteria. Antioxidant activity was evaluated for bare GO, Ag and Ag-RGO nanocomposite by DPPH radical scavenging assay. It was observed that Ag/RGO nanocomposite has enhanced antioxidant activity than bare GO and Ag.
Adsorptive stripping differential pulse voltammetry determination of rivastig...Pramod Kalambate
The study of graphene nanosheet (GNS)–gold nanoparticle (AuNP)–carbon paste electrode (GNS–AuNP–CPE) as
an electrochemical sensor for the determination of rivastigmine (RIV) in pharmaceuticals formulations, blood
serum, and urine samples is presented. The GNS–AuNP composite is prepared by in situ simultaneous reduction
of graphene oxide and chloroauric acid using sodiumborohydride as a reducing agent. The GNS–AuNP composite
was characterized by X-ray diffraction, UV–Vis spectroscopy, and scanning electron microscopy. Electrochemical
characterization of the GNS–AuNP–CPE electrode surfacewas carried out by cyclic voltammetry, electrochemical
impedance spectroscopy, chronocoulometry, and adsorptive stripping differential pulse voltammetry. This study
shows that oxidation of rivastigmine is facilitated at the GNS–AuNP–CPE electrode and remarkably increase in
current compared to the bare electrode due to enhanced adsorption of the former on electrode surface. Under
the optimized conditions, the peak current (Ip) is found to be proportional to the RIV concentration in the
range of 2.0 × 10–7–6.0 × 10−4 M with a detection limit of 5.3 × 10−8 M. The proposed sensor shows a very
high level of sensitivity, selectivity, and a very good reproducibility for RIV determination. A good recovery
level obtained for real samples suggests practical utility of the GNS–AuNP–CPE as an effective and reliable electrochemical
sensor for RIV detection.
—3-Chloro-1,2-propanediol (3-chloropropanediol) is a well-known food processing contaminant found in a wide range of foods and ingredients and there has been recent concern about the levels of carcinogenic 3-chloropropanediol (3-MCPD) in some soy sauces. This paper reports on the development of an analytical method for the fast determination of 3-MCPD at trace level in commercial soy sauce using novel liquid phase extraction (LPE)/cleanup coupled with microwave-assisted derivatization (MAD) method followed by high performance liquid chromatography-ultraviolet (HPLC-UV) detection. In this method, 3-MCPD was first isolated from soy sauce sample matrix by LPE/cleanup with Extrude NT3 column cartridges and the isolated (eluent) solution was subjected to MAD with acetophenone to form 2-methyl-2-phenyl-4-(chloromethyl)-1,3-dioxolane under microwave irradiation using a specially modified domestic microwave oven, then the derivatizeddioxolane was directly analyzed with a HPLC-UV system. The optimum conditions for MAD such as the ratio of reagents, acidic catalyst, microwave irradiation power and time, as well as the chromatographic conditions were thoroughly investigated. Experimental results indicated that maximum derivatization can be achieved in 10 min under microwave irradiation at 362 watts when compared to 18 hours by conventional refluxing reaction. The proposed method provided a simple and rapid analytical procedure for 3-MCPD analysis in soy sauce with the detection limit of 80 ng mL-1. The relative standard deviations were all below 3.0 % (n = 7). Application was illustrated by the analysis of commercial sauce sample obtained from a local traditional store in central Taiwan.
Antioxidant biosensor based on D. radiodurans biofilm has been investigated in this research. The biofilm producing SOD enzymes were immobilized on SPCE surface. Optimization of experimental measurements were carried out by the response surface method. The optimum value obtained was at the buffer pH 7, suspension pH 6, and optical density (OD) 0.5. The morphology of SPCE surfaces was characterized by SEM. The optimum result was used to determinate analytical performance, including linearity, sensitivity, limit of detection (LOD), limit of quantity (LOQ), precision, selectivity, stability, and repeatability. Linearity was achieved in the xanthine concentration range of 0.1-0.6 mM with the equation y = 40.79x + 57.173 and R² = 0.99. The apparent Michaelis-Menten constant KMwas evaluated. It was found that the biosensor had alow KMof 40 μM. LOD and LOQ respectively 40.8 μM and 123.7 μM with sensitivity 40.79 μA mM-1. Precision showed that RSD was less than 5%. Stability was measured for 35 days andretained 90% of current for the period. Repeatability showedRSD ≤ 5%. The selectivity of this method still needs to increase. In conclusion, antioxidant biosensor based on D. radioduransbiofilm may be used to measure the capacity of antioxidant products practically.
Synthesis of graphene oxide-TiO2 nanocomposite as an adsorbent for the enrich...Nanomedicine Journal (NMJ)
Abstract
Objective(s):
In our study, graphene oxide-TiO2 nanocomposite (GO/TiO2) was prepared and used for the enrichment of rutin from real samples for the first time.
Materials and Methods:
The synthesized GO/TiO2 was characterized by X-ray diffraction, scanning electron microscopy, and FT-IR spectra. The enrichment process is fast and highly efficient. The factors including contact time, pH, and amount of GO/TiO2 affecting the adsorption process were studied.
Results:
The maximum adsorption capacity for ciprofloxacin was calculated to be 59.5 mg/g according to the Langmuir adsorption isotherm. The method yielded a linear calibration curve in the concentration ranges from 15 to 200 μg/L for the rutin with regression coefficients (r2) of 0.9990. The limits of detection (LODs, S/N=3) and limits of quantification (LOQs, S/N=10) were found to be 8 μg/Land 28 μg/L, respectively. Both the intra-day and inter-day precisions (RSDs) were < 10% .
Conclusion:
The developed approach offered wide linear range, and good reproducibility. Owing to the diverse structures and unique characteristic, GO/TiO2 possesses great potential in the enrichment and analysis of trace rutin in real aqueous samples.
Physicochemical and Spectroscopic Characterization of Biofield Energy Treated...wilhelm mendel
The p-anisidine is widely used as chemical intermediate in the production of various dyes, pigments, and pharmaceuticals. This study was aimed to evaluate the effect of biofield energy treatment on the physicochemical and spectroscopic properties of p-anisidine. The study was performed after dividing the sample in two groups; one was remained as untreated and another was subjected to Mr. Trivedi’s biofield energy treatment. Afterward, both the control and treated samples of p-anisidine were evaluated using X-ray diffraction (XRD), surface area analyzer, differential scanning calorimetry (DSC), thermogravimetric analysis-derivative thermogravimetry (TGA-DTG), Fourier transform infrared (FT-IR), and ultraviolet-visible (UV-Vis) spectroscopy. The XRD analysis showed the increase in unit cell volume from 683.81 → 690.18 × 10-24 cm3 and crystallite size from 83.84→84.62 nm in the treated sample with respect to the control. The surface area analysis exhibited the significant increase (25.44%) in the surface area of treated sample as compared to control. The DSC thermogram of control p-anisidine showed the latent heat of fusion and melting temperature and 146.78 J/g and 59.41°C, respectively, which were slightly increased to 148.89 J/g and 59.49°C, respectively after biofield treatment. The TGA analysis showed the onset temperature of thermal degradation at 134.68°C in the control sample that was increased to 150.02°C after biofield treatment. The result showed about 11.39% increase in onset temperature of thermal degradation of treated p-anisidine as compared to the control. Moreover, the Tmax (temperature at which maximum thermal degradation occurs) was also increased slightly from 165.99°C (control) to 168.10°C (treated). This indicated the high thermal stability of treated p-anisidine as compared to the control. However, the FT-IR and UV spectroscopic studies did not show any significant changes in the spectral properties of treated p-anisidine with respect to the control.
Applications of gold nanoparticles in medicine and therapyAl Baha University
The stability and dispersity of AuNMs in solution play a key role for the many applications. Most inorganic nanomaterials are not well dispersed in physiological buffers and require function-alization by thiols or surfactants to offer the stabilization forces. Furthermore, sufficient blood circulation time is critical for both imaging and in vivo drug delivery. Localized surface Plasmon resonance (LSPR) is one of the most significant features of AuNMs. The AuNMs as reporters have been broadly applied into lateral flow immunechromatographicalassay (LFICA) and enzyme-linked immunosorbent assay (ELISA), which is a well-established technology for analysis of the target analytes in food safety, clinical diagnosis, environmental monitoring, and medical science and so on. Au based nanomaterials (AuNMs) are known to possess many attractive features such as unique electrical, optical and catalytic properties as well as excellent biocompatibility. In this review, we summarize the current advancement on application of AuNMs in analytical sciences based on their local surface plasmon resonance, fluorescence and electrochemistry properties. AuNMs based imaging and therapy in biomolecules is explained. As one of the most reliable imaging modes, computed tomography (CT), X-ray and SERS imaging has been widely used owing to its high spatial and density resolution. We end the review by a discussion of the conjugation between gold nanoparticles with other kinds of nanoparticles such as other metals and carbon nano structures. Finally, future development in this research area is also prospected.
Characterization of Liquid Waste in Isotope production and Research Facilitiesiosrjce
IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Ninhydrin Based Visible Spectrophotometric Determination of GemigliptinRatnakaram Venkata Nadh
A simple method is described to determine the amount of gemigliptin in bulk and tablet formulation by visible spectrophotometry. Basis of the proposed method is the reaction of the primary amine present on gemigliptin with ninhydrin in alkaline pH (alkaline borate buffer) medium to produce a purple color (Ruhemann’s purple) which has maximum absorption at 558 nm. The method was validated as per the current ICH guidelines. The obtained regression equation (y = 0.0148x+0.0011) in the range of 5-30 μg mL-1 has a good correlation coefficient (> 0.999). As the method does not require any separation, it is rapid and simple. The recovery levels of the drug were in the range of 99.73 – 99.96. This method is a green method as it no organic solvents were employed
Ninhydrin Based Visible Spectrophotometric Determination of GemigliptinRatnakaram Venkata Nadh
A simple method is described to determine the amount of gemigliptin in bulk and tablet formulation by visible spectrophotometry. Basis of the proposed method is the reaction of the primary amine present on gemigliptin with ninhydrin in alkaline pH (alkaline borate buffer) medium to produce a purple color (Ruhemann’s purple) which has maximum absorption at 558 nm. The method was validated as per the current ICH guidelines. The obtained regression equation (y = 0.0148x+0.0011) in the range of 5-30 μg mL-1 has a good correlation coefficient (> 0.999). As the method does not require any separation, it is rapid and simple. The recovery levels of the drug were in the range of 99.73 – 99.96. This method is a green method as it no organic solvents were employed
Observation of Io’s Resurfacing via Plume Deposition Using Ground-based Adapt...Sérgio Sacani
Since volcanic activity was first discovered on Io from Voyager images in 1979, changes
on Io’s surface have been monitored from both spacecraft and ground-based telescopes.
Here, we present the highest spatial resolution images of Io ever obtained from a groundbased telescope. These images, acquired by the SHARK-VIS instrument on the Large
Binocular Telescope, show evidence of a major resurfacing event on Io’s trailing hemisphere. When compared to the most recent spacecraft images, the SHARK-VIS images
show that a plume deposit from a powerful eruption at Pillan Patera has covered part
of the long-lived Pele plume deposit. Although this type of resurfacing event may be common on Io, few have been detected due to the rarity of spacecraft visits and the previously low spatial resolution available from Earth-based telescopes. The SHARK-VIS instrument ushers in a new era of high resolution imaging of Io’s surface using adaptive
optics at visible wavelengths.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
The increased availability of biomedical data, particularly in the public domain, offers the opportunity to better understand human health and to develop effective therapeutics for a wide range of unmet medical needs. However, data scientists remain stymied by the fact that data remain hard to find and to productively reuse because data and their metadata i) are wholly inaccessible, ii) are in non-standard or incompatible representations, iii) do not conform to community standards, and iv) have unclear or highly restricted terms and conditions that preclude legitimate reuse. These limitations require a rethink on data can be made machine and AI-ready - the key motivation behind the FAIR Guiding Principles. Concurrently, while recent efforts have explored the use of deep learning to fuse disparate data into predictive models for a wide range of biomedical applications, these models often fail even when the correct answer is already known, and fail to explain individual predictions in terms that data scientists can appreciate. These limitations suggest that new methods to produce practical artificial intelligence are still needed.
In this talk, I will discuss our work in (1) building an integrative knowledge infrastructure to prepare FAIR and "AI-ready" data and services along with (2) neurosymbolic AI methods to improve the quality of predictions and to generate plausible explanations. Attention is given to standards, platforms, and methods to wrangle knowledge into simple, but effective semantic and latent representations, and to make these available into standards-compliant and discoverable interfaces that can be used in model building, validation, and explanation. Our work, and those of others in the field, creates a baseline for building trustworthy and easy to deploy AI models in biomedicine.
Bio
Dr. Michel Dumontier is the Distinguished Professor of Data Science at Maastricht University, founder and executive director of the Institute of Data Science, and co-founder of the FAIR (Findable, Accessible, Interoperable and Reusable) data principles. His research explores socio-technological approaches for responsible discovery science, which includes collaborative multi-modal knowledge graphs, privacy-preserving distributed data mining, and AI methods for drug discovery and personalized medicine. His work is supported through the Dutch National Research Agenda, the Netherlands Organisation for Scientific Research, Horizon Europe, the European Open Science Cloud, the US National Institutes of Health, and a Marie-Curie Innovative Training Network. He is the editor-in-chief for the journal Data Science and is internationally recognized for his contributions in bioinformatics, biomedical informatics, and semantic technologies including ontologies and linked data.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Richard's entangled aventures in wonderlandRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
2. F. Nemati et al. / Sensors and Actuators B 255 (2018) 2078–2085 2079
the intrinsic defects of those QDs limit their widespread applica-
tion, such as complex synthesis procedures, heavy metals potential
toxicity and environmental hazards [24]. Graphene quantum dots
(GQDs) are generally defined as zero-dimensional carbon-based
material that are typically single or few-layer graphenes with lat-
eral dimensions of less than 100 nm [25,26]. Owing to the novel
properties, such as remarkable conductivity, high edge-to-area
ratio, stable luminescence, good biocompatibility, and low toxicity,
graphene quantum dots have recently emerged as promising alter-
natives to traditional quantum dots in some aspects [27]. However,
the photoluminescence quantum yield of the pristine GQDs is usu-
ally low and much lower than semiconductor quantum dots [28].
Recently demonstrated that high quantum yields of GQDs quantum
yield can be observed after either functionalization or doping [29].
Among foreign atoms, Nitrogen has been widely used for chem-
ical doping in carbon-based nanomaterials by virtue of it having
match able atomic size and five valence electrons for bonding with
carbon atoms [30,31]. The optimization in analytical chemistry is
generally carried out with a traditional single variable approach
(SVA) [32]. Its major disadvantage is that it ignores the combination
influence among the parameters studied. Due to above disadvan-
tage, multivariate statistic methods have been applied to optimize
experimental parameters. Among the most relevant multivari-
ate techniques, response surface methodology (RSM) has shown
considerable application in analytical optimization [33]. Response
surface methodology, a collection of mathematical and statistical
techniques, is a very useful tool for determining the effect of opera-
tional variables for process development and optimization [34,35].
The most frequent and efficient methods used in response surface
methodology is central composite design (CCD) [36]. The aim of
this work was to develop a simple, fast and non-toxic method, of
maximum possible sensitivity, to detection of thiamine in phar-
maceuticals and foodstuff samples. For this, we have synthesized
water-soluble Arg-GQDs by using citric acid and Arginine (Arg) as
carbon and nitrogen sources respectively. Based on the excellent
photoluminescent of the Arg–GQDs, a simple, potent, fast, non-
toxic fluorescent probe was designed. In this paper, the influence
of time, temperature and pH on fluorescence sensing was investi-
gated using response surface methodology (RSM) based on central
composite design (CCD). The range of linearity, the stability, the
response to interferents and the detection limit (LOD) of the sensor
have been evaluated. The optical sensor based on the Arg-GQDs has
been successfully applied in sensitive detection of thiamine in real
spiked samples.
2. Experimental section
2.1. Chemicals and materials
Citric acid (+99%), Arginine were purchased from Sigma–Aldrich
Co. Thiamine hydrochloride (98%) was purchased from Alfa
Aesar. All the other chemicals used were of analytical reagents
grade. Stock standard solution of thiamine hydrochloride
(1.0 × 10−3 mol L−1) was prepared in water and stable for at
least 1 month when kept refrigerated. Working solutions of lower
concentrations were prepared daily from the above stock solution
as required. All chemicals used were of analytical grade or of the
highest purity available. All solutions were prepared with doubly
deionized water (DDW).
2.2. Apparatus
UV–vis measurements were carried out on a PG Instruments
T80+ UV/Vis spectrophotometer and the spectra were collected
from 200 nm to 700 nm. All fluorescence measurements were
carried out by a Perkin-Elmer LS50 luminescence spectrometer.
Fourier transform infrared (FT-IR) spectrum was recorded on a
Shimadzu-8400S spectrometer in the range of 400–4000 cm−1 at
room temperature using KBr pellets. Energy-dispersive X-ray (EDX)
spectra were obtained using the Philips XL30 scanning electron
microscope (SEM). The morphologies of Arg-GQDs samples were
characterized by transmission electron microscopy (TEM, Philips,
CM30, 300 Kv). The pH was adjusted and measured using pH meter
Metrohm. The X-ray diffraction patterns (XRD) were recorded on
a Philips diffractometer (model X’Pert MPD). Raman spectrum was
recorded using an Almega Thermo Nicolet Dispersive Raman Spec-
trometer with a 532 nm laser.
2.3. Synthesis of functionalized graphene quantum dots
In a typical synthesis, 0.21 g of citric acid and 0.10 g of Arginine
were mixed with 5 mL water, and stirred to form a clear solu-
tion. The solution was then transferred into a 20 mL Teflon-lined
stainless autoclave. The sealed autoclave was heated constantly
at 160 ◦C for 4 h. The obtained mixture was filtered with a mem-
brane (0.22 m) to remove the large dots. Finally, the as prepared
Arg-GQDs were stored at 4 ◦C for further experiments.
2.4. General procedure
For thiamine detection, 25 L of 40 mg mL−1 Arg-GQDs, 1 mL pH
6 phosphate buffer and 40 L (0.01 M) of Ag+ solution were added
in a quartz cuvette and the mixture was stirred thoroughly. Then,
the mixture was finally diluted to 2 mL with ultrapure water. Next,
different amounts of thiamine added to the above mixed solution.
Finally, the fluorescence intensity of the mixture was recorded at
excitation wavelength of 350 nm, and the band-slits of both exci-
tation and emission were set as 10.0 and 15.0 nm, respectively.
2.5. Quantum yield measurements
The quantum yield of the as-synthesized GQDs were determined
by using quinine sulfate as the fluorescence standard and was cal-
culated according to the following Eq. (1):
Yu = Yst
Iu
Ist
Ast
Au
n2
u
n2
st
(1)
Where Y is the quantum yield, I is the measured integrated emission
intensity, n is the refractive index, and A is the extinction. The sub-
script “st” refers to the standard and “u” for sample with unknown
QY.
2.6. Analysis of thiamine in real samples
Fluorescent detection of thiamine in food samples was per-
formed through the following steps: 1.0 g of samples that was
purchased from a local supermarket was grounded and mixed with
0.1 mol L−1 HCl solution. After integrating for 15 min, the mixture
was centrifuged for 15 min at 5000 rpm, and the supernatant was
filtered through a 0.45 mm cellulose acetate filter and diluted up to
10 mL with ultra-pure water. The pharmaceutical sample (vitamin
B1 tablet from Jalinous Pharmaceutical Co., Iran) was obtained from
the local drug store. For analysis, a piece of vitamin B1 tablet was
powdered in a mortar and dissolved in ultrapure water. The mixture
was sonicated for 10 min for fully dissolution. The insoluble com-
ponents were removed by filtration. After that, the solution was
transferred into 25 mL volumetric flask and stored in dark at 4 ◦C.
Standard addition method was used for determination of thiamine
in the real samples.
3. 2080 F. Nemati et al. / Sensors and Actuators B 255 (2018) 2078–2085
Fig. 1. (a) TEM image of the Arg-GQDs (inset: size distribution of Arg-GQDs) (b) EDX spectrum of the Arg-GQDs (c) Raman spectra of as-prepared Arg-GQDs (d) XRD patterns
of the Arg-GQDs.
Table 1
Experimental factors and levels in CCD.
Levels
Independent variable -␣ -1(low) 0 (center) +1(High) +␣
(x1) pH 4 5 6 7 8
(x2) time(min) 5 10 15 20 25
(x3) temperature (
◦
C) 25 30 35 40 45
2.7. Optimization of factors affecting the fluorescence sensing of
thiamine using RSM approach
Central composite design was applied to investigate the effects
of the three operational factors on the response function. The
studied parameters were selected based on the preliminary experi-
ments and prior knowledge from literature. The high and low levels
defined for three independent variables are shown in Table 1. After
running the 20 trials, a second order polynomial model for predict-
ing the optimal point was explained by the following Eq. (2):
Y = ˇ0 +
k
i=1
ˇixi +
k
i=1
k
j=i+1
ˇijxixj +
k
i=1
ˇiix2
i
(2)
In the above equation, Y is the predicted response; xi and xj are
independent factors and ˇ0 is the intercept. ˇi and ˇii are the lin-
ear and quadratic coefficients, respectively. While ˇij represents
the interaction coefficients. Design Expert software version 7 was
employed to analyze the data and the design of the experiment.
Table 2
The design matrix for four variables with enhancement ratio (F- F0)/F0 as response
(R).
Runs Block x1 x2 x3 (F − F0)/F0
1 1 6 15 35 2.73
2 1 7 10 30 2.68
3 1 5 10 30 2.54
4 1 5 20 40 2.26
5 1 5 20 30 2.10
6 1 7 20 30 2.48
7 1 7 20 40 2.43
8 1 7 10 40 2.28
9 1 5 10 40 2.09
10 1 6 15 35 2.60
11 2 6 15 35 2.55
12 2 6 15 35 2.49
13 2 8 15 35 2.02
14 2 6 15 45 2.39
15 2 6 15 35 2.53
16 2 4 15 35 1.37
17 2 6 15 35 2.70
18 2 6 25 35 2.51
19 2 6 5 35 2.37
20 2 6 15 25 2.75
The design matrix and enhancement ratio (F − F0)/F0 as response
are presented in Table 2.
4. F. Nemati et al. / Sensors and Actuators B 255 (2018) 2078–2085 2081
Fig. 2. (a) FT-IR spectrum (b) UV–vis absorption (c) fluorescence excitation and
emission spectra of Arg-GQDs.
3. Results and discussion
3.1. Characterization of GQDs
The Arg-GQDs were synthesized by the hydrothermal approach
described in the Experimental Section. TEM images gave the first
confirmation that nano-sized pieces formed during the synthesis
of NGQDs. Fig. 1a shows the TEM image of N-GQDs. Uniformly dis-
persed Arg-GQDs in a narrow size distribution were observed. And
the mean diameter of Arg-GQDs was estimated to be 5.5 nm.
Analysis of elemental composition of the prepared Arg-GQDs
was performed using EDX. The EDX spectrum of the N-GQD showed
the presence of elements O, N, and C (Fig. 1b).Raman spectrum of
the of Arg-GQD is shown in Fig. 1c. There are two closely peaks
at around 1600 cm−1 (G band) and 1400 cm−1(D band), respec-
tively, which were assigned to in-plane vibrations of crystalline
graphite and disordered structures of the sp2 domains. For more
information about the structure, X-ray diffraction (XRD) analysis
was performed. There is a diffraction peak at range of 21.8–24.4◦
on the XRD pattern, which attributed to graphitic structure [37,38].
Fig. 2a showed the FT-IR spectrum of N-CQDs in the wavelength
range of 500–4000 cm−1. The absorption band at 3420 cm−1 was
assigned to O H stretching vibration. The characteristic absorption
peaks for C = C at 1571 cm−1 and C C at 1234 cm−1 were observed,
indicating the existence of delocalized -electrons in Arg-GQDs
molecules. The absorption peaks around 3172 cm−1 and 1451 cm−1
were belonged to of N H and C N stretching vibration, respec-
tively [39]. This result further confirmed the doping of N in the
as-prepared sample. Moreover, three absorption peaks appeared
at 1451 cm−1and 1109 cm−1, corresponding to the stretching vibra-
tions of COO and C O groups, respectively. These functional groups
could stabilize Arg-GQDs in aqueous media. The as-prepared Arg-
GQDs solution remains homogeneous even after 2 months at room
temperature without any perceptible changes (e.g., aggregation or
color change), which could be further characterized by the almost
unchanged absorption and PL spectra (Fig. S1). To further explore
the optical properties of the N-GQDs, UV–vis absorption and FL
spectra were recorded. As shown in Fig. 2b, UV–vis absorption spec-
trum of the GQD shows a typical absorption peak at ca. 210 nm
was observed, which is assigned to the –* transition of aro-
matic C C sp2 domains. Another strong absorption peak at 340 nm
can be regarded as the n–* transition of the C O bone, which
can result in strong fluorescence [40]. The GQD solution emitted
strong blue FL under excitation at 365 nm by a UV lamp (inset of
Fig. 2a). However, it was light yellow, transparent and clear under
daylight (inset of Fig. 2b). As shown in Fig. 2c, the Arg-GQDs exhib-
ited a maximum emission at 448 nm with an excitation wavelength
of 350 nm. Compared to the non-doped GQDs, the present Arg-
GQDs show blue-shifted emission, which could be ascribed to the
strong electron affinity of the doped nitrogen [41]. It should be
noted that the excitation peak is very close to the absorption peak,
suggesting the high-efficient emitting absorption of the Arg-GQDs.
The quantum yield of the Arg-GQDs was calculated to be 28.3%.
The photostability of as-synthesized Arg-GQDs under UV irradia-
tion was studied. As shown in Fig. S2, the fluorescence intensity of
Arg-GQDs remained constant within the studied range, indicating
excellent photo-stability of the as-prepared Arg-GQDs. The effects
of ion strength on the fluorescence of Arg-GQDs was also inves-
tigated in the presence of different concentrations of NaCl. The
signal intensity measured of the Arg-GQDs. When concentrations
of NaCl is 0.1–2 M, the measured fluorescence was nearly constant,
indicating the high stability of Arg-GQDs under high salt medium.
3.2. Optimization of sensing conditions
Based on CCD experiment, the effects of detection parame-
ters; incubation time, pH value and temperature were evaluated.
According to experimental data, using software the second-order
polynomial was used to describe the response variable (F − F0/F0)
and interaction among the variables as follows Eq. (3):
F − F0/F0 = +2.60 + 0.14x1 − 0.003750x2
− 0.090x3 + 0.027x1x2 − 0.020x1x3
+ 0.12x2x3 − 0.22x1
2
− 0.036x2
2
0.003542x3
2
(3)
Where x1, x2 and x3 are pH, time and temperature, respectively. In
order to test the validity and adequacy of the model and the effect
of operational variables and their interactions, ANOVA was per-
formed. The ANOVA is a collection of statistical models, and their
associated procedures, in which the observed variance in a particu-
lar variable is partitioned into components attributable to different
sources of variation. It provides a statistical test of whether or not
the means of several groups are all equal [42]. The reliability of
the suggested model was assessed by the coefficient of determina-
tion (R2 and adjusted-R2). An R2 of 0.9532 and an adjusted-R2 of
0.9065 indicated excellent correlation between experimental val-
ues and fitted model, and showed a high- efficiency designed model
for prediction of response. Based on ANOVA data, the amounts of
F-value (20.38) and p-value (less than 0.0001) implies that defined
model is significant. The “lack-of-fit (LOF) P-value” of this model
(0.6243) is in significant because of its amount is more than 0.05
5. 2082 F. Nemati et al. / Sensors and Actuators B 255 (2018) 2078–2085
Fig. 3. The predicted response vs. the observed response.
Fig. 4. A plot of the internally studentized residuals vs. the predicted response.
critical value; thus, the non-significant lack-of-fit confirm the ade-
quacy of a model fit. Fig. 3 indicates the predicted responses versus
observed data. Most residuals were proximity close to the straight
line, which indicates a good relationship between actual data and
fitted model as a cause of large R2 values.
The plot of the residuals versus the predicted data (Fig. 4) con-
firms that the points were distributed randomly. In next step, to
observe the individual and interactive effect of the variables on
enhancement ratio (F − F0)/F0, 3-D surface plots and contour plots
were used. The responses plotted relative to the two significant
variables, while the other factor is fixed at its central level [43].
The goal of the response surface is to find the optimum values
of the factors, such that the response is maximized [44]. Fig. 5a
depicts the effect of pH, time and their mutual interaction on the
response. Thiamine has been reported to get oxidized at alkaline
medium to generate the thiochrome [45]. Hence, the pH effect was
studied in the 4–8 range. Result show that by increasing the pH of
solution, the enrichment ratio increases. This is related to protona-
tion of the carbonyl groups and hydroxyl groups on the surface of
Arg-GQDs that occur at the acidic pH. In other hand, at high con-
centration of H+ ions, the formation of hydrogen bond between
oxygen-containing functional groups on the surface of GQDs lead
to the aggregation of GQDs [46]. A pH of 6 was selected for the fur-
ther thiamine sensing. As can be seen from Fig. 5a–c, the higher
temperature leads to a decrease in the response surface and had an
inverse effect on enhancement ratio. The fluorescence signal of a
graphene quantum dot is very sensitive to temperature. The quan-
tum efficiency includes radiative and non-radiative decay of excited
states. The enhance in non-radiative decay rate at higher temper-
ature leads to decrease in quantum efficiency and corresponding
Fig. 5. Response using the central composite design obtained by plotting: (a) time
vs. pH, (b) temperature vs. pH, (c) time vs. temperature.
fluorescence intensity [47]. Effects of incubation time and temper-
ature on the enhancement ratio are shown in Fig. 5c. Incubation
time and temperature both had inverse effect on the enhancement
ratio, while the interaction between incubation time and temper-
ature was negatively correlated with response. The enhancement
ratio can be adjusted by changing the time because it decreases the
temperature. Therefore, the low temperature leads to an increase
in the initial intensity. The optimum predicted point of maximum
enhancement ratio obtained by Design-Expert software is about
2.77, and the corresponding optimal parameters of adsorption pro-
cess are listed as below: time 10 min, temperature 30 ◦C, pH 6.
3.3. Possible mechanism
Upon addition of Ag+ ion to the dispersion of the Arg- GQDs, a
decrease in fluorescence intensity of Arg-GQDs is observed (Fig. 6).
The nature of quenching was attributed to the coordination of Ag+
and the functional groups of Arg-GQDs. According to HSAB (hard
and soft acids and bases) principle, the soft acids and soft bases
tend to have a strong interaction [48]. Thus, Ag+ ions (soft acids)
could have a high affinity with nitrogen atoms in Arg-GQDs surface
(soft bases) and form conjugation of the Arg-GQDs- Ag+ complex
[49]. Thus, the fluorescence of Arg-GQDs was quenched by the addi-
tion of Ag+ ions. The interaction between Arg-GQDs and Ag+ was
6. F. Nemati et al. / Sensors and Actuators B 255 (2018) 2078–2085 2083
Fig. 6. Fluorescence responses Arg-GQDs in the presence of several of Ag+
.
studied by FT-IR spectra (Fig. S4). When Ag+ is present in Arg-GQDs
solution, the peak position of N H stretching vibration band moves
from 3172 to 3170 cm−1 and the peak position of COO− stretch-
ing vibration band moves from 1451 to 1454 cm−1, together with
the decrease in the peak intensities of these two bands. The peak
intensities of 3420 also decreased, confirming the binding interac-
tion between Arg-GQDs and Ag+. These results indicate that Ag+
interacted with functional groups present on the obtained Arg-
GQDs. According to the experimental result, we considered that
thiamine with thiazole ring would show strong binding ability
with Ag+ through an Ag S bond [50]. Obviously, the fluorescence
intensity of the quenched N-GQD recovered with increasing con-
centration of thiamine in the system. This enhancement could be
a result of interaction between Ag+ and the thiamine. This result
was further confirmed by the Zeta potential measurement of Arg-
GQDs at different condition (Fig. S5). A significant shift of the zeta
potential from −28.1 mV of free N-GQDs to −12.6 in the presence of
Ag+ shows the interaction between Arg-GQDs and Ag+ ions. On the
other hand, the increase of the zeta potential to −22.3 mV resulted
from the reaction of the Ag+ with thiamine, which successfully
confirms the remove of Ag+ ions from the surface of the N-GQDs.
3.4. Analytical characteristics
To demonstrate the sensing performance of this proposed assay
for thiamine detection, we evaluated the response of this sensor
by adding varying concentrations of thiamine under experimen-
tal optimal conditions (Fig. 7a). Fig. 7b presents the relationship of
the enhancement ratio (F − F0)/F0 (F0 and F are the fluorescence
intensities of Arg-GQDs at 448 nm in the absence and presence
of thiamine, respectively) with the concentration of thiamine. The
inset of Fig. 7b shows that the (F − F0)/F0 has a good linear correla-
tion with the concentration of thiamine in the range of 0.1–8 M,
and the linear regression equation is y = 0.4505 + 0.0556C, where C
is the concentration of thiamine (M). The corresponding regres-
sion coefficient was 0.995 and the detection limit of this method
for thiamine was 53 nM (S/N = 3). Furthermore, the analytical per-
formance of the proposed sensing system for thiamine detection is
comparable to those reported (Table 4).
3.5. Selectivity
In order to understand the selectivity of the reported assay
and interference to thiamine detection, the effect of some com-
pounds abundant in the selected real samples on the fluorescence
behavior of probe was examined. Under the optimal conditions, the
developed method was used to including pyridoxine (vitamin B6),
cyanocobalymine (vitamin B12), ascorbic acid (vitamin C), niacin
Fig. 7. (a) Fluorescence response of Arg-GQDs containing Ag +
to various con-
centrations of thiamine. (b) Plot of the enhancement ratio (F − F0)/F0 vs thiamine
concentration. The Inset shows a linear relationship in the concentration range from
0.1 to 8 M.
Table 3
Analytical results of thiamine in food samples and vitamin B1 tablet (n = 3).
Sample Added (M) Found (M) Recovery (%, n = 3) RSD (%, n = 3)
Green pea 0.3 0.28 93 2.9
2 1.95 97 3.1
Sunflower 0.3 0.31 103 1.4
2 2.05 102 3.7
Wheat flour 0.3 0.29 96 4.5
2 2.11 105 2.3
VB1 tablet 0 2.34 – 4.8
0.3 2.61 90 3.6
2 4.41 103.5 2.8
(vitamin B3), folic acid (vitamin B9), 100-fold glucose, sucrose, fruc-
tose, lactose, cellulose and1000-fold Na+, K+, Ca2+ and Mg2+. As
shown in Fig. 8a, various interference showed a negligible influence
on the fluorescence intensity of the quenched Arg-GQDs, except for
the fluorescence recovery induced by thiamine. In addition, a com-
petitive experiment for the effect of interferences on the recovery
fluorescence intensity of Arg-GQDs by thiamine was also operated
using the current assay under the same conditions. The result shows
that no change in the fluorescence response of probe towards thi-
amine was observed in the presence of interferences (Fig. 8b). These
results indicate that the as-synthesized Arg-GQDs can be used as
effective fluorescence probe for thiamine detection.
3.6. Application of the fluorescent Arg-GQDs in real sample
To demonstrate the feasibility of the sensing system for detec-
tion in real samples, the fluorescence assay was applied for
thiamine sensing in pharmaceuticals and foodstuff samples by the
7. 2084 F. Nemati et al. / Sensors and Actuators B 255 (2018) 2078–2085
Table 4
Comparison of the present approach with other reported methods for the detection of thiamine.
Method Technique in detail Linearity LOD Ref.
Fluorescence Eu-doped Y2O3 nanoparticles 0–44 M 0.144 M [5]
Fluorescence carbon dots 10–50 M 0.280 M [45]
luminescence CdSe quantum dots 15–120 M 0.207 M [46]
Electrochemical luminescence Rhodamine B 0.3–5 M 0.265 M [47]
HPLC-CLD-UV – 0.07–27 M 0.030 M [48]
Fluorescence N-GQDs 0.1–8 M 0.053 M Present work
Fig. 8. (a) The fluorescence enhancement factors [(F0 − F)/F0] of the Arg-GQDs con-
taining Ag+
with a series of interfering substance and thiamine. (b)The fluorescence
intensities of N-GQDs-Ag+
with thiamine in the presence of interfering substance.
standard addition technique. The samples were diluted to make
sure the thiamine concentration in the real samples were within the
linear range. The obtained results were listed in Table 3. The recov-
ery of thiamine for spiked samples were in the range of 90%–103.5%,
whereas the relative standard deviations range were no more than
4.8%. The obtained results were listed in Table 3. The results indi-
cated that the designed sensor was a reliable method for thiamine
analysis in real samples.
4. Conclusion
In summary, we have developed Arg-GQDs-based fluorescent
sensor for detection of trace amounts of thiamine in pharmaceutical
and foodstuff samples. Arg-GQDs, synthesized via a facile one-step
hydrothermal approach, were demonstrated to be a fluorescent
probe for label-free determination of thiamine with high sensi-
tivity and selectivity. The presence of Ag+ caused the quenching
of fluorescence intensity of Arg-GQDs owing to the coordination
reaction between Ag+ and Arg-GQDs, while subsequent addition
of thiamine restores the fluorescence intensity caused the quench-
ing of fluorescence intensity. The effects of independent variables
were successfully optimized by the assessment of central compos-
ite design. The experimental results which were obtained during
the sensing of thiamine, were found to be fitted with model pre-
diction. The adequacy of regression model was tested by lack-of-fit
(LOF), F values and P values. Furthermore, the proposed method
has been utilized to accurately detect thiamine in practical samples.
Our present work provides the advantage of simplicity, sensitivity,
low cytotoxicity and selectivity.
Acknowledgements
The financial support of this study by Iran University of Science
and Technology, University of Tehran and Iran Nanotechnol-
ogy Initiative Council are gratefully acknowledged. The author
acknowledges financial support from the Iran National Science
Foundation (INSF).
Appendix A. Supplementary data
Supplementary data associated with this article can be found, in
the online version, at http://dx.doi.org/10.1016/j.snb.2017.09.009
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Biographies
Fatemeh Nemati is a Ph.D. student in Analytical Chemistry at Iran University of
Science and Technology, Tehran, Iran.
Rouholah Zare-Dorabei has a PhD in Analytical Chemistry obtained at University
of Tehran in 2010. He is currently Assistant Professor in Analytical Chemistry Iran
University of Science and Technology, Tehran, Iran. His research work has been
mainly focused on the design of new optical sensors.
Morteza Hosseini has a Ph.D. in analytical chemistry obtained at Tarbiat Modares
University in 2005. He is currently an associated professor in nanobiotechnology
group of Faculty of New Sciences and Technologies of University of Tehran. His
research work has been mainly focused on the design of new optical nanosensors
and nanobiosensors.
Mohammad Reza Ganjali has a Ph.D. in analytical chemistry obtained at University
of Tehran in 1997. He is currently a professor of analytical chemistry at University of
Tehran. His research work has been mainly focused on the design of new chemical
sensors.