To detemine the wavelength of semiconductor laserPraveen Vaidya
The laser is part of almost all industrial sectors now. Laser is a coherent highly monochromatic concentrated beam of light.
Right from the computer data reading to metal welding the laser is used. The PowerPoint presentation here explains the laser experiment to determine the wavelength of a semiconductor laser, my the method of Grazing incidence (diffraction over the graduations of metal scale). The aim is to study the diffraction of patterns of laser scattered from the graduations of metal scale and hence determine the wavelength. The experiment is part of the physics curriculum in Technological universities and other science colleges.
Electromagnetic radiation consists of photons, the quanta of electromagnetic fields. A freely-propagating photon in empty space (gravity-free, zero curvature vacuum) is described as a self-sustaining, helical traveling wave packet of quantized spin angular momentum moving at the speed of light. A photon is categorized as a stable, massless boson having no electric charge with spin angular momentum s = +/- hbar. The spin axis is aligned with the direction of wave vector k in either the forward or backward direction depending on helicity.
The observed EM frequency spectrum spans more than 140 octaves or ~24 orders of magnitude. The cutoff frequency of the vacuum is taken as the Planck frequency fsubP = 1.855E43 Hz.
To detemine the wavelength of semiconductor laserPraveen Vaidya
The laser is part of almost all industrial sectors now. Laser is a coherent highly monochromatic concentrated beam of light.
Right from the computer data reading to metal welding the laser is used. The PowerPoint presentation here explains the laser experiment to determine the wavelength of a semiconductor laser, my the method of Grazing incidence (diffraction over the graduations of metal scale). The aim is to study the diffraction of patterns of laser scattered from the graduations of metal scale and hence determine the wavelength. The experiment is part of the physics curriculum in Technological universities and other science colleges.
Electromagnetic radiation consists of photons, the quanta of electromagnetic fields. A freely-propagating photon in empty space (gravity-free, zero curvature vacuum) is described as a self-sustaining, helical traveling wave packet of quantized spin angular momentum moving at the speed of light. A photon is categorized as a stable, massless boson having no electric charge with spin angular momentum s = +/- hbar. The spin axis is aligned with the direction of wave vector k in either the forward or backward direction depending on helicity.
The observed EM frequency spectrum spans more than 140 octaves or ~24 orders of magnitude. The cutoff frequency of the vacuum is taken as the Planck frequency fsubP = 1.855E43 Hz.
A dimensionless quantity described as a fundamental physical constant characterizing the coupling strength of the electromagnetic interaction. Introduced by Sommerfeld in 1916 to describe the spacing of splitting of spectral lines in multi-electron atoms, it is formed from four physical constants: electric charge, speed of light in vacuo, Planck's constant and electric permittivity of free space.
The inverse fine structure constant (=137.035999...) represents the spin precession whirl no. of the electron. The electron exhibits a slight precession due to an imbalance of electrostatic and magnetostatic energy levels. Electric charge is a result of this spin precession and represents a loop closure failure (torsion defect) similar to topological charge.
Rest mass results from quantum wave interference due to precession. Hence, electric charge, rest mass and the fine structure constant are interrelated and directly calculable.
In this lecture, we will be talking only about the interaction of an ionizing electromagnetic radiation with matter, specifically about the interaction of X-Rays with the matter
Note: Gamma rays interact with the matter by the same way that X-rays interact with matter. In this lecture, we just focused on X-rays to complete our previous lecture about the production of X-rays
A dimensionless quantity described as a fundamental physical constant characterizing the coupling strength of the electromagnetic interaction. Introduced by Sommerfeld in 1916 to describe the spacing of splitting of spectral lines in multi-electron atoms, it is formed from four physical constants: electric charge, speed of light in vacuo, Planck's constant and electric permittivity of free space.
The inverse fine structure constant (=137.035999...) represents the spin precession whirl no. of the electron. The electron exhibits a slight precession due to an imbalance of electrostatic and magnetostatic energy levels. Electric charge is a result of this spin precession and represents a loop closure failure (torsion defect) similar to topological charge.
Rest mass results from quantum wave interference due to precession. Hence, electric charge, rest mass and the fine structure constant are interrelated and directly calculable.
In this lecture, we will be talking only about the interaction of an ionizing electromagnetic radiation with matter, specifically about the interaction of X-Rays with the matter
Note: Gamma rays interact with the matter by the same way that X-rays interact with matter. In this lecture, we just focused on X-rays to complete our previous lecture about the production of X-rays
The chapter contains fundamentals of Modern physics, the Quantumtheory explanation of Black body radiation photoelectric effect and Compton effect, and the beginning of the de-Broglie hypothesis, wave-like properties of matter, and its proof explained in detail. It is highly useful for first-year B.Tech and BE students.
4 radio wave propagation over the earthSolo Hermelin
Describes the Electromagnetic Wave Propagation over the Earth Surface. Please send comments to solo.hermelin@gmail.com.
For more presentations on different subjects pleade visit my website at http://www,solohermelin.com.
This presentation is in the Radar folder.
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.
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.
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.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
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.
3. Working Principle of Laser
Einstein’s assumptions & implications
Thermodynamic equilibrium at arbitrary
temperature T exists between the radiation field
and the atoms
The spectral density u(ν) of the radiation energy
has the distribution characteristics of a blackbody
at temperature T
The atom population densities Nl and Nu at energy
levels El and Eu, respectively, are distributed
according to the Boltzman distribution at that
temperature
Population densities Nl and Nu are constant in time
4. Working Principle of Laser
The radiative process and assumptions above, it follows
that the rate of change of atoms in level Eu is given by
( ) ( )υυ uBNuBNAN
dt
dN
lululuulu
u
+−−== 0
The spectral energy density can be written as
( )
1
18
/3
33
−
= kTh
ec
hn
u υ
υπ
υ
The Boltzman distribution
( ) kTh
l
ukTEE
l
u
l
u
e
g
g
e
g
g
N
N lu // υ−−−
==
…..(1)
…..(2)
…..(3)
5. Working Principle of Laser
Solving eq.(1) in terms of u(υ) and substituting Nu/Nl from
eq. (3), we obtain
( )
( )
ul
kTh
lu
u
l
ul
ulullu
ul
BeB
g
g
A
BNNB
A
u
−
=
−
=
// υ
υ
Compare it to eq. (2), gives
3
33
8
c
hn
B
A
ul
ul υπ
= lululu BgBg =
……(5) ……(6)
……(5)
6. Working Principle of Laser
The importance of eqs. (5) and (6) cannot be underestimated.
They tell us that:
(i) The fundamental Einstein’s coefficients Aul, Bul and Blu are all
inter-related.
(ii) guBul = glBlu , i.e. stimulated emission and absorption are
inverse processes. However note that the rate dNu/dt and
dNl/dt differ depending on the population densities Nu and Nl.
If Nu > Nl it leads to an increase in u(υ), an amplification. And
if Nl > Nu it leads to a decrease in u(υ), an attenuation. For
laser to operate, it is necessary that Nu be greater than Nl – a
condition called population inversion.
(iii) Since Bul/Aul is proportional to the reciprocal of the cube of
the frequency, the higher the frequency the smaller Bul
becomes in comparison with Aul. Since Bul is related to
stimulated emission and Aul is related to spontaneous
emission, it would seem that lasers of short wavelength
radiation would be more difficult to build and operate.Two important ideas for the successful operation of a laser
emerge from a review of Einstein’s study of the interaction of
electromagnetic radiation with matter are, stimulated emission
and population inversion.
7. Lasing condition
Population inversion
Necessary condition for amplification.
The case of the upper level being more populated than the lower level.
If stimulated emission rate exceeds absorption rate, net optical gain.
The relationship for the intensity at a specific distance z into medium
at a frequency ν and width Δν can be expressed as,
9. Population inversion
If the value of the exponent is positive, the
beam will increase in intensity and so
amplification will occur.
If it is negative, the beam will decrease in
intensity and absorption will occur.
The values of σul and z are always positive, thus
amplification will occur only if
This condition is not normal under thermal
equilibrium
l
l
u
N
g
g
N =u
11. Emission Broadening
Homogeneous Broadening
Due to the isotropic collisions with other atoms, which also
causes non-radiative decay
The processes lead to a Lorentzian distribution of emitting
frequencies
All of the atoms in level u have an equal probability of
participating in the emission at any frequency ν of that
emission shape – all atoms behave the same way
12. Emission Broadening
Homogeneous Broadening
The process can decrease either the decay time τu of
the atoms residing in the excited level u OR affect the
linewidth – depending on collision intervals
Dephasing collisions interrupts the phase of radiating
atoms without increasing their population decay rate
13. Emission Broadening
Inhomogeneous
Do not affect the lifetime, but do affect the linewidth
The processes include Amorphous Crystal broadening,
Doppler broadening and Isotope broadening
Emission processes that lead to a Gaussian distribution of
emitting frequencies
Specific portions of the population density Nu contribute to
different portions of the emission linewidth
14. Emission Broadening
Amorphous Crystal Broadening
Glass materials have various small regions
oriented in slightly different directions
Thus, each of the glass molecules can have
slightly different energy levels
This leads to different radiating frequencies for
different regions
Since the emission line is composed of the sum of
all of the individual lines, this leads to a much
broader emission spectrum
15. Emission Broadening
Doppler Broadening
Due to random movements of radiating atoms in all
directions with a range of velocities
This causes frequency shifts depending on the
directions of the movements
The faster the atoms move on the average, the broader
the bandwidth
A single photon might be able to stimulate one atom to
emit because that atom happened to be Doppler shifted
to the photon’s frequency, but it might not be able to
stimulate another atom because it had a different
Doppler shift than the first
I.e. different atoms contribute to the gain at different
frequencies within the laser bandwidth
16. Emission Broadening
Isotope Broadening
Due to the presence of more than one isotropic
form of the species
These different isotopes consist of atoms having
the same number of protons and electrons, but
with different numbers of neutrons
Atoms with slightly different numbers of neutrons
within their nuclei exhibit small differences in
energy level values
The slightly different energy level values for
different isotopes provide slightly different
frequencies for the transitions
