The document discusses microwave assisted synthesis of metallic nanostructures. Some key points:
1) Microwave irradiation can be used to synthesize a variety of metallic nanostructures like spheres, sheets, rods, wires, and dendrites.
2) Microwave heating allows for faster, cleaner reactions compared to traditional heating methods. It enables selective heating and precise temperature control.
3) Examples demonstrate synthesizing gold nanoparticles within minutes using microwave heating, stabilizers, and reducing agents, achieving smaller, more uniform particles than traditional heating.
4) Microwave synthesis has advantages like short reaction times, low energy input, selective heating, and ability to control morphology of nanostructures produced. It is considered a green chemistry approach
Transmission electron microscope, high resolution tem and selected area elect...Nano Encryption
The transmission electron microscope is a very powerful tool for material science. A high energy beam of electrons is shone through a very thin sample, and the interactions between the electrons and the atoms can be used to observe features such as the crystal structure and features in the structure like dislocations and grain boundaries. Chemical analysis can also be performed. TEM can be used to study the growth of layers, their composition and defects in semiconductors. High resolution can be used to analyze the quality, shape, size and density of quantum wells, wires and dots.
This presentation includes basis of lithography i.e. (photo-lithography e-beam lithography) in nano-lithography includes (AFM, Soft, NIL and DPN lithography)
It's simple to understand the synthesis. Hydrothermal method is a chemical reaction in water in a sealed pressure vessel, which is in fact a type of reaction at both high temperature and pressure.
It an overall view on two research papers. Biological synthesis of Nano particles from plants and microorganisms
and the synthesis of metallic Nano particles using plant extract
Transmission electron microscope, high resolution tem and selected area elect...Nano Encryption
The transmission electron microscope is a very powerful tool for material science. A high energy beam of electrons is shone through a very thin sample, and the interactions between the electrons and the atoms can be used to observe features such as the crystal structure and features in the structure like dislocations and grain boundaries. Chemical analysis can also be performed. TEM can be used to study the growth of layers, their composition and defects in semiconductors. High resolution can be used to analyze the quality, shape, size and density of quantum wells, wires and dots.
This presentation includes basis of lithography i.e. (photo-lithography e-beam lithography) in nano-lithography includes (AFM, Soft, NIL and DPN lithography)
It's simple to understand the synthesis. Hydrothermal method is a chemical reaction in water in a sealed pressure vessel, which is in fact a type of reaction at both high temperature and pressure.
It an overall view on two research papers. Biological synthesis of Nano particles from plants and microorganisms
and the synthesis of metallic Nano particles using plant extract
Power Point Presentation on GREEN CHEMISTRY
(info on pollution, causes and its prevention)
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Got Distance? You'll know if you look at your calendar and see most meetings have dial in numbers. This talk delivered for the TriAgile 2016 conference shows 8 categories of approaches you can use to help with today's distributed team landscape.
MERITS OF MICROWAVE ASSISTED REACTIONS
DEMERITS OF MICROWAVE ASSISTED REACTIONS
MECHANISM OF MICROWAVE HEATING
EFFECTS OF SOLVENTS IN MICROWAVE ASSISTED SYNTHESIS
MICROWAVE VERSUS CONVENTIONAL SYNTHESIS
MICROWAVE INSTRUMENTATION
VARIOUS TYPES OF MICROWAVE ASSISTED ORGANIC REACTIONS
APPLICATIONS OF MICROWAVE ASSISTED REACTIONS
Enhancement of rate of heat transfer using nano fluidsSharathKumar528
Nano fluids as coolants and lubricants is still very primitive in technology. This presentation explores the future of nano fluids for enhanced heat transfer.
The present work demonstrates for the first time the facile fabrication of TiO2
nanotube arrays (TNTAs) by a fluoride-free
solid-state anodization process using LiClO4
containing solid polymeric electrolyte. The resulting nanotubes were tested
for photoelectrochemical water splitting. The elimination of liquid electrolytes in electrochemical anodization constitutes
a paradigm shift for the formation of nanoporous and nanotubular metal oxides. Our results open a new area of research
that uses the distinctive properties of solid polymer electrolytes to achieve targeted doping and nano-morphologies. Characterization
of the grown TNTAs indicated solid state anodized TNTAs to consist purely of the anatase phase of titania.
The solid-state anodization process provides several advantages over conventional liquid electrolytes such as easy handling
and processing, better charge transport, environmentally benign chemicals and methodology. Photoelectrochemical water
splitting experiments were performed which confirmed the viability of TNTAs grown by the new solid-state process for
photocatalytic applications.
Preparation of nano phosphors by Microwave-assisted combustion synthesisEditor IJCATR
In this review article, we have discussed synthesizing of nano phosphor materials by the Microwave assisted Combustion
process. Several literature conclude that efficient synthesis of nano phosphor materials can be achieved only through microwave-assisted
combustion method. Also we have discussed about the principle and working process behind the Microwave process. After undergoing
literature survey on combustion process we have discussed the preparation process of fuel to oxidizer ratio which plays a major role for
obtaining nano powders that are essential in display application
We'd like to understand how you use our websites in order to improve them. Re...Pawan Kumar
The present work demonstrates for the first time the facile fabrication of TiO2 nanotube arrays (TNTAs) by a fluoride-free solid-state anodization process using LiClO4 containing solid polymeric electrolyte. The resulting nanotubes were tested for photoelectrochemical water splitting. The elimination of liquid electrolytes in electrochemical anodization constitutes a paradigm shift for the formation of nanoporous and nanotubular metal oxides. Our results open a new area of research that uses the distinctive properties of solid polymer electrolytes to achieve targeted doping and nano-morphologies. Characterization of the grown TNTAs indicated solid state anodized TNTAs to consist purely of the anatase phase of titania. The solid-state anodization process provides several advantages over conventional liquid electrolytes such as easy handling and processing, better charge transport, environmentally benign …
Comparative study on ammonia sensing properties of sno2 nanocomposites fabric...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
The threat of global warming is high due to the extensive use of fossil fuels.Using non-renewable resources is a viable solution. Sunlight can be converted in two ways - into electrical energy and into chemical energy. Water splitting and CO2 are two important methods which can be used in solar cells.
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 IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
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.
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.
2. A GREEN CHEMISTRY APPROACH
Green chemistry is the utilization of a set of principles that
reduces or eliminates the use or generation of hazardous
substances in the design, manufacture and application of
chemical products.
A variety of metallic nanostructures, including spherical particles,
sheets, plates, rods, wires, tubes, and dendrites can be
achieved by microwave irradiation.
Out of the 12 principles of green chemistry, the following are
taken care through MW synthesis
Prevention of waste
Less hazardous chemical synthesis
Design for energy efficiency
Inherently safer chemistry for accident prevention
2
4. POSSIBLE EFFECTS OF MW HEATING
There are two kinds of effects of MW dielectric heating: thermal
and non-thermal
Thermal effects
k =A*e
Loss tangent factor
Superheating effects of solvents at atmospheric pressure
Selective heating of microwave absorbing reagents and catalysts
Elimination of wall effects
4
5. 5
Non thermal
effects
Polar reaction
mechanism
Interaction of
electric field with
reaction medium
molecules
Orientation of
molecules
Increase in
polarity from
ground state to
transition state
Lowering of
activation energy
Increase in
reactivity
6. Preparation of Au spherical nanoparticles:
Au nanoparticles have been synthesized by reduction of Au salts in
various solvents under oil-bath heating for many hours. When HAuCl4
was reduced in methanol or ethanol,[for 0.5–5 min in the presence of PVP
under MW heating (480– 1100 W), mono dispersed, small spherical
nanoparticles, with diameters below 11 nm, were synthesized within a
few minutes.
Spherical Au particles by using a closed chamber of an MW system with
precise temperature control function.
When HAuCl4 was reduced in an aqueous solution containing citrate as a
stabilizer for 15– 30 min, Au particles sizes could be reduced from 85 to
13 nm with increasing reaction temperature, heating time, and rate of
temperature increase.
6
7. A commercial MW oven is modified by installing a condenser and thermocouple
through holes in the top and a magnetic stirrer plate coated with Teflon in the
bottom of the oven.
A thermocouple made of an optical fiber, which is not damaged under MW
irradiation, is used.
A glass flask is placed in the MW oven with a power of 300– 1100 W and
connected to a condenser, into which a mixture of metallic salt, surfactant,
and, if necessary, a small amount of nucleation reagent is added.
A surfactant such as polyvinyl pyrrolidone (PVP) acts as a stabilizer for the
product nanostructures. The reagent solution is irradiated by MW in a
continuous wave (CW) mode or a pulse mode.
The pulse mode is more useful for the temperature control of the heating
media. Products particles are generally characterized by using transmission
electron microscopy (TEM), scanning electron microscopy (SEM), selected area
electron diffraction (SAED) pattern, X-ray diffraction (XRD), and UV visible
absorption spectroscopy.
Before measuring the TEM photographs, surfactants were often separated from
nanostructures by centrifugation.
7
10. ADVANTAGES
faster reactions
less byproducts
pure compounds
absolute control over reaction parameters
selective heating / activation of catalysts
low energy input (max=300w, typical reaction ~20w)
green solvents (H2O, EtOH, acetone) used
less solvent usage ( 0.5-5mL per reaction)
software-supported experiment documentation
10
11. APPLICATIONS
Heck reaction
Suzuki reaction
Negishi and Kumada reaction
Multicomponent reactions
Solid phase synthesis
Reactions in the absence of solvents
11
12. CONCLUSION
Uniform heating of the solution
Homogeneous nucleation
Shorter crystallization time
Short thermal induction period, which can lead to energy savings
Selective formation of specific morphology
Absence of convection processes, easy control, and low cost.
DISADVANTAGE:
MW heating is a promising heating method, a further wide application to
preparation and control of various kinds of metallic nanostructures, which
are key materials in nanotechnology, is expected.
Unfortunately, detailed mechanism for the preparation of metallic
nanostructures under MW irradiation has not been clarified.
12
13. 13
REFERNCE:
Microwave-Assisted Synthesis of Metallic Nanostructures in
Solution
Masaharu Tsuji,*[a] Masayuki Hashimoto,[b] Yuki Nishizawa,[b]
Masatoshi Kubokawa,[b] and Takeshi Tsuji
Solid State Ionics
F. Fievet, J. P. Lagier, B. Blin, B. Beaudoin, M. Fiflarz
