Raman spectroscopy uses laser light to study vibrational and rotational modes in molecules. When light interacts with molecules, the light may be scattered at different wavelengths than the incident laser, providing information about the molecule's structure and bonds. Raman spectroscopy has advantages over infrared spectroscopy in that it can be used to study samples in liquid or solid form, including aqueous solutions. It finds applications in elucidating molecular structure, biological analysis, and quantitative and qualitative analysis of materials.
Raman Spectroscopy is a non destructive chemical analysis technique which provides detailed information about chemical structure, crystallinity and molecular interactions. The raman effect involves scattering of light by molecules of gases, liquids, or solids. Raman Spectroscopy is sensitive to homo-nuclear molecular bonds. It is able to distinguish between single, double, and triple bonds between carbon atoms.Raman spectroscopy is the study of matter by the inelastic scattering of monochromatic
light. It has become a ubiquitous tool in modern spectroscopy, biophysics, microscopy, geochemistry, and analytical chemistry. In contrast to typical absorption or emission spectroscopy experiments, transitions among quantum levels of atoms or molecules are induced by the absorption or emission of photons (IR, visible, UV). In a typical Raman experiment, a polarized monochromatic light source (usually a laser) is focused into a sample, and the scattered light at 90 degree
to the laser beam is collected and dispersed by a high-resolution monochromator. The incident laser wavelength (chosen such that
the sample does not absorb, in ordinary Raman Spectroscopy) is fixed, and the scattered light is
dispersed and detected to obtain the frequency spectrum of the scattered light. The scattered light is very weak
(<10-7 of the incident power), so that monochromators with excellent straylight rejection and sensitive detectors are required. In a much rarer event (approximately 1 in 10million photons)Raman scattering occurs, which is an inelastic scattering process with a transfer of energy between the molecule and scattered photon. If the molecule gains energy from the photon during the scattering (excited to a higher
vibrational level) then the scattered photon loses energy and its wavelength increases which is called Stokes Raman scattering . Inversely, if the molecule loses energy by relaxing to alower vibrational level the scattered photon gains thecorresponding energy and its wavelength decreases;
which is called Anti-Stokes Raman scattering. • Quantum mechanically Stokes and Anti-Stokes areequally likely processes. However, with an ensemble of molecules, the majority of molecules will be in the ground vibrational level (Boltzmann distribution) and Stokes scatter is the statistically more probable process. As a result, the Stokes Raman scatter is always more intense than the anti-Stokes and for this
reason, it is nearly always the Stokes Raman scatter that is measured in Raman spectroscopy. Raman spectroscopy is used in chemistry to identify molecules and study chemical bonding and intramolecular bonds.In solid-state physics, Raman spectroscopy is used to characterize materials, measure temperature, and find the crystallographic orientation of a sample . In nanotechnology, a Raman microscope can be used to analyze nanowires to better understand their structures, and the radial breathing mode of carbon nanotubes is commonly used to evaluate their diameter.
Raman spectroscopy.pptx M Pharm, M Sc, Advanced Spectral AnalysisDiwakar Mishra
Raman Spectroscopy is included in the syllabus Advanced Spectral Analysis (Pharmaceutical Chemistry) which discribes the principle and working of Raman Spectroscopy.
Although the inelastic scattering of light was predicted by Adolf Smekal in 1923, it was not observed in practice until 1928. The Raman effect was named after one of its discoverers, the Indian scientist C. V. Raman, who observed the effect in organic liquids in 1928 together with K. S. Krishnan, and independently by Grigory Landsberg and Leonid Mandelstam in inorganic crystals. Raman won the Nobel Prize in Physics in 1930 for this discovery. The first observation of Raman spectra in gases was in 1929 by Franco Rasetti.
(May 29th, 2024) Advancements in Intravital Microscopy- Insights for Preclini...Scintica Instrumentation
Intravital microscopy (IVM) is a powerful tool utilized to study cellular behavior over time and space in vivo. Much of our understanding of cell biology has been accomplished using various in vitro and ex vivo methods; however, these studies do not necessarily reflect the natural dynamics of biological processes. Unlike traditional cell culture or fixed tissue imaging, IVM allows for the ultra-fast high-resolution imaging of cellular processes over time and space and were studied in its natural environment. Real-time visualization of biological processes in the context of an intact organism helps maintain physiological relevance and provide insights into the progression of disease, response to treatments or developmental processes.
In this webinar we give an overview of advanced applications of the IVM system in preclinical research. IVIM technology is a provider of all-in-one intravital microscopy systems and solutions optimized for in vivo imaging of live animal models at sub-micron resolution. The system’s unique features and user-friendly software enables researchers to probe fast dynamic biological processes such as immune cell tracking, cell-cell interaction as well as vascularization and tumor metastasis with exceptional detail. This webinar will also give an overview of IVM being utilized in drug development, offering a view into the intricate interaction between drugs/nanoparticles and tissues in vivo and allows for the evaluation of therapeutic intervention in a variety of tissues and organs. This interdisciplinary collaboration continues to drive the advancements of novel therapeutic strategies.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
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.
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.
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.
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 .
2. Sir Chandrasekhara Venkata
Raman
• November 7, 1888 - November 21,
1970
• Won the Nobel prize in 1930 for Physics
• Discovered the “Raman effect”
• Besides discovering the Raman effect he
• studied extensively in X-ray
Diffractions.
• phenomenon
4. Introduction
Raman spectroscopy deals with the scattering of light and not with its
absorption,homonuclear diatomic molecules such as H2 ,O2,N2 Etc.
Which do not show I.R. spectra since they do not posses a permanent
dipole movement do show raman spectra since there vibration is
accompanied by change polarizability of the molecules.
It gives imformation about molecular vibration that are inactive in the
infrared region bcz molecular symmetry
When a substance (in any state) irradiated with monochromatic light or
photon of definite frequency light are scattered at right angle to the
incident light
The frequency of scattered light is simillar to incident light and somim it
may lower or higher the frequency than the incident light it is to be
known as raman scattering
Raman spectroscopy has another advantages in that is uses visible or
ultra violet radiation rather than I.R.radiation
5. Stoke line: The frequency of scattered light is
lower than the incident light is know as the
stoke line
Antistoke line : The frequiency of scattered light
is greater than incident light is known as anti-
stoke line
Raileigh scattering: The frequency of incident
light is equil to scattered light is known as
raileigh scattering
6. ‘Principle’
When light is incident on sample ,the molecules are absorb the light
and it may gives collisions of molecules
There are lot of molecules and most of collision are identical that
means the freq. of incident light is equel to the scattering light
But there is some molecule which have other frequency that means
there are may be greater than the incident light or less than the
incidernt light
Raman Scattering
a
7.
8. Quantum Theory of Raman Scattering
v0 > vs v0 = vs v0 < vs
= v0 - vs =0 = v0 + vs
9. INSTRUMENTATION
Instrumentation for modern Raman spectroscopy consists of three
components:
A laser source, a sample illumination system and a suitable
spectrometer.
1. Source
2. Sample Illumination System
3. Raman Spectrometers
Source
The sources used in modern Raman spectrometry are nearly
always lasers because their high intensity is necessary to produce
Raman scattering of sufficient intensity to be measured with a
reasonable signal-to-noise ratio. Because the intensity of Raman
scattering varies as the fourth power of the frequency, argon and
krypton ion sources that emit in the blue and green region of the
spectrum have and advantage over the other sources.
10.
11. Sample Illumination System
Liquid Samples: A major advantage of sample handling in Raman
spectroscopy compared with infrared arises because water is a
weak Raman scatterer but a strong absorber of infrared radiation.
Thus, aqueous solutions can be studied by Raman spectroscopy but
not by infrared. This advantage is particularly important for
biological and inorganic systems and in studies dealing with water
pollution problems.
Solid Samples: Raman spectra of solid samples are often acquired
by filling a small cavity with the sample after it has been ground
to a fine powder. Polymers can usually be examined directly with
no sample pretreatment.
Gas sample:Gas are normally contain glass tubes 1-2 cm diameter
and about1mm in thick.Gases can also be sealed in capillary tubes.
12. Raman Spectrometers
Raman spectrometers were similar in design and used
the same type of components as the classical
ultraviolet/visible dispersing instruments.
Most employed double grating systems to minimize the
spurious radiation reaching the transducer.
Photomultipliers served as transducers.
Grating used in raman spectroscopy.
Typical grating used for R.S.vary from 300 groove/mm(low
resolution)through 1800 groove/mm (high resolution)
16. Difference between IR & Raman
spectroscopy
IR
It is the result of absorption of
light by vibrating molecule.
The presence of permanent
dipole moment in a molecule
may be regarded as a critereon
of IR spectra.
It requires at least two separate
runs.
Water cannot be used as a
solvent.
Method is accurate& sensitive
Raman
It is the result of Scattering of light
by vibrating molecule.
Polarizability of the molecule will
decide whether the raman spectra
will be observed or not.
It can be recorded in only one
exposure.
Water can be used as a solvent
Method is very accurate but is not
very sensitive
17. Optical systems are made up of
special crystals such as CaF2,NaBr,
NaCl etc.
Generally dilute solutions are
preffered.
Homonuclear diatomic molecules
are not found tobe IR active.
Optical systems are made up of
glass or quartz.
Raman lines are weeker in
intensity so concentrated solutions
are preffered.
Homonuclear diatomic molecules
are found tobe active.
18. Advantages
Water can be used as solvent.
Very suitable for biological sample
Glass and quartz ,lenses,cells and optical fibers can be used
Standard detecrtor used
Disadvantages
Complicated and costly equiupments
Not suitable for vibrations of bond with very ;low polarizability
19. Application
Elucidation of molecular structure
Biological Applications of Raman Spectroscopy
Study ionic equilibria
Study of hydrogen bonded equilibria
Qualitatve analysis (identification)
Quantitative analysis (estmation)