This document discusses gas chromatography (GC), which separates compounds that can be vaporized without decomposing. It has two types depending on the stationary phase: gas-solid chromatography (GSC) and gas-liquid chromatography (GLC). The distribution of analytes between phases is expressed by the distribution constant K. Plate theory and rate theory, including the Van Deemter equation, are presented to describe column efficiency and factors influencing peak broadening such as eddy diffusion, longitudinal diffusion, and mass transfer under non-equilibrium conditions.
In this slide contains principle of IR spectroscopy and sampling techniques.
Presented by: R.Banuteja (Department of pharmaceutical analysis).
RIPER, anantpur.
In this slide contains principle of IR spectroscopy and sampling techniques.
Presented by: R.Banuteja (Department of pharmaceutical analysis).
RIPER, anantpur.
This presentation contains all the topics related to column chromatography. That includes introduction, principle,apparatus, experimental aspects of column chromatography, application of column chromatography, advantage and disadvantage of column chromatography with reference.
In this slide contains Interference In Atomic Absorption Spectroscopy and applications.
Presented by: Shaik Gouse ul azam. ( department of pharmaceutical analysis.)
RIPER, anantpur.
In this slide contains principle, instrumentation, methodology, and application of gel chromatography.
Presented by: SATHEES CHANDRA (Department of pharmaceutical analysis).
RIPER, anantapur
a substance can absorb any visible light or external radiation and then again emit it. this called fluorescence and the process of reduction in fluorescence intensity is called quenching. this presentation is all about quenching of fluorescence.
This presentation contains all the topics related to column chromatography. That includes introduction, principle,apparatus, experimental aspects of column chromatography, application of column chromatography, advantage and disadvantage of column chromatography with reference.
In this slide contains Interference In Atomic Absorption Spectroscopy and applications.
Presented by: Shaik Gouse ul azam. ( department of pharmaceutical analysis.)
RIPER, anantpur.
In this slide contains principle, instrumentation, methodology, and application of gel chromatography.
Presented by: SATHEES CHANDRA (Department of pharmaceutical analysis).
RIPER, anantapur
a substance can absorb any visible light or external radiation and then again emit it. this called fluorescence and the process of reduction in fluorescence intensity is called quenching. this presentation is all about quenching of fluorescence.
Department of Chemistry /College of Sciences/ University of Baghdad
Subject: Analytical Chemistry 4
Second stage
2nd semester
Dr. Ashraf Saad Rsaheed
2017-2018
Column Chromatography: basics of chromatography and principle of chromatography, Classification, partition coefficient , chromatogram, retention time and volume, capacity and selectivity factors, plate theory, band broadening, rate theory, mass transfer, packed GLC column, open tubular column capillary columns, liquid chromatography column resolution.
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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.
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.
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 .
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.
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.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
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.
2. Gas Chromatography
Gas chromatography is a common type of
chromatography used in analytical chemistry for
separating and analyzing the compounds that can be
vaporized without decomposition.
It has two types
• Mobile Phase : Gas
• Stationary Phase: SolidGSC
• Mobile Phase : Gas
• Stationary Phase : LiquidGLC
3. The distribution of an analyte between stationary and mobile
phase is expressed by the distribution constant K.
K = Cs/Cm
Cs = concentration of a component in the stationary phase
Cm = concentration of a component in the mobile phase
In case of GSC, the interaction of solutes with the stationary
phase is in the form of their adsorption on it & this adsorption is
non-linear.
This does not keep the ratio of the concentration of a solute in
the stationary phase (Cs) to that in the mobile phase (Cm)
constant.
In case of the GLC ratio of the concentration of a solute in the
stationary phase (Cs) to that in the mobile phase (Cm) constant.
4. Isotherm for Linear-Nonideal
GLC
Isotherm for Nonlinear-Nonideal
GSC
The isotherm is a graphical representation of the distribution
constant K
CS = concentration in stationary phase;
CG = concentration in mobile phase at equilibrium.
5. Plate Theory
The theory assumes that the column is divided into a
number of zones called theoretical plates.
At each plate equilibrium of the solute between the
mobile phase & the stationary is assumed to take place.
The partitioning of a solute between the phases takes
plate at each theoretical plate.
Thus, the number theoretical plates in the column is
used as a measure of efficiency of the column to
separate the components from each other
6. The number of theoretical plates can be determined
by
where, n = no. of theoretical plates
VR = retention time
W = base width of the peak
7. HETP value can be determined by,
Plate theory disregards the kinetics of mass transfer;
therefore, it reveals little about the factors influencing
HETP values.
The resulting behavior of the plate column is calculated on
the assumption that the distribution coefficient remains
unaffected by the presence of other solutes and that the
distribution isotherm is linear.
The diffusion of solute in the mobile phase from one plate
to another is also neglected.
9. Discrete-Flow Model
The assumptions in this model are
(a)
• All the mobile phase moves from one segment to
the next segment at the end of a discrete interval
(b)
• The sample molecules are always in equilibrium
with the mobile and stationary phases
10. Continuous-Flow Model
The assumptions in this model are
(a)
• The mobile and stationary phases remain in
equilibrium throughout the separation
(b)
• The mobile phase flows from one segment to the next
segment at a constant rate
(c)
• Perfect mixing takes place in all segments
11. Rate Theory
It was introduced by Van Deemter.
It describes the effect of an elution band as well as its
time of elution.
Van Deemter equation describes the relation of the
height of a theoretical plate H and the average linear
velocity of the mobile phase.
12. Van Deemter Equation
H = height of a theoretical plate
u = average linear velocity of the mobile phase
A = eddy diffusion term
B = longitudinal or ordinary diffusion term
C = nonequilibrium or resistance to mass transfer term
13. Eddy Diffusion
The A term refers to band broadening caused by
dispersion (multi-pathway) effects (Eddy diffusion)
A = 2λdp
λ = correction factor for the irregularity of the column
packing
dp = average particle diameter.
14. In this case the spaces along the column are not uniform.
When a sample migrates down the column, each molecule “sees”
different paths and each path is of a different length.
Some molecules take the longer paths and others take the
shorter paths.
There are also variations in the velocities of the mobile phase
within these pathways.
The overall result is that some molecules lag behind the center of
the zone, whereas others move ahead of the zone.
15. Longitudinal Diffusion
The B term represents band broadening by
longitudinal diffusion, the molecular diffusion both in
and against the flow direction:
B = 2γDG
γ = labyrinth factor of the pore channels (0<γ <1)
DG = diffusion coefficient of the analyte in the gas
phase
16. This process results when there exists a region of high
concentration and a region of low concentration.
The migration is from the higher to the lower
concentration region in the axial direction of the column.
Diffusion occurs on the molecular level, resulting from
movement of molecules after collision
The diffusion is about 100–1,000-fold faster in gases than in
liquids, therefore B terms shows higher impact in GC than
in LC.
17. Mass transfer under non equilibrium
The C terms refers to the mass transfer between stationary and
mobile phase.
As the zone of solute continues to migrate down the column, it is
constantly bringing an ever-changing concentration profile in
contact with the next part of the column. This effect results in
different rates of equilibration along the column.
Thus theoretical plate in the column is constantly attempting to
equilibrate with a variable concentration zone in the mobile phase.
At one time the zone attempts to equilibrate with a low
concentration in the mobile phase, and then at another time with a
high concentration.
These overall processes result in nonequilibrium at each theoretical
plate.
18. The rapid mass transfer depends on the factors originating from
the stationary phase as well as the mobile phase The term ‘C’ in
Van Deemter equation is therefore, the sum of Cs & CM.
The stationary phase contribution (Cs) to the plate height H, due
to the mass transfer under nonequilibrium condition, is given by,
q = configuration factor
r = a constant dependent upon the relative rate of migration of a
solute & the mobile phase,
d = thickness of the stationary phase
Ds = diffusion coefficient of a solute in the stationary phase.
19. The mobile phase contribution (CM) to the plate
height H, due to the mass transfer under
nonequilibrium conditions, is given by,
DG = diffusion coefficient in the gas phase
dp = average particle diameter
ω = obstruction factor for packed bed
20. Van Deemter Plot
The term ‘A’ is independent
of flow rate of the mobile
phase
The term B/u decreases
drastically in the beginning
with increase in the flow rate
of mobile phase. Increase in
the flow rate beyond
particular value, leads to slow
decrease in the value of B/u.
The term Cu increases with
increse in the flow rate