It is over 60 years since Hodgkin and
Huxley1 made the first direct recording of
the electrical changes across the neuronal
membrane that mediate the action
potential. Using an electrode placed inside a
squid giant axon they were able to measure a
transmembrane potential of around 260 mV
inside relative to outside, under resting
conditions (this is called the resting membrane
potential). The action potential is a
transient (,1 millisecond) reversal in the
polarity of this transmembrane potential
which then moves from its point of initiation,
down the axon, to the axon terminals. In a
subsequent series of elegant experiments
Hodgkin and Huxley, along with Bernard
Katz, discovered that the action potential
results from transient changes in the permeability
of the axon membrane to sodium (Na+)
and potassium (K+) ions. Importantly, Na+ and
K+ cross the membrane through independent
pathways that open in response to a change
in membrane potential.
As testimony to their pioneering work, the
fundamental mechanisms described by
Hodgkin, Huxley and Katz remain applicable
to all excitable cells today. Indeed, the
predictions they made about the molecular
mechanisms that might underlie the changes
in membrane permeability showed remarkable
foresight. The molecular basis of the action
potential lies in the presence of proteins
called ion channels that form the permeation
pathways across the neuronal membrane.
Although the first electrophysiological
recordings from individual ion channels were
not made until the mid 1970s,2 Hodgkin and
Huxley predicted many of the properties now
known to be key components of their
function: ion selectivity, the electrical basis
of voltage-sensitivity and, importantly, a
mechanism for quickly closing down the
permeability pathways to ensure that the
action potential only moves along the axon in
one direction.
these slides contain a brief introduction of neurons and its classification as well as details of generation of action potential, resting potential and eletrotonic potential.
these slides contain a brief introduction of neurons and its classification as well as details of generation of action potential, resting potential and eletrotonic potential.
Action potential By Dr. Mrs. Padmaja R Desai Physiology Dept
To study the Concept of Action Potential and describe the stages of action potential.
Ionic basis of Action Potential & its Propogation.
Properties of Action Potential.
Types action Potential
Nervous system forms an interconnecting fibers of communication network.
In the ‘hard-wiring’ of the nerves, the signals travel in the form of a flow of electrical current called nerve impulses.
The stimulus-response reactions afford internal constancy in the face of environmental changes.
Action potential By Dr. Mrs. Padmaja R Desai Physiology Dept
To study the Concept of Action Potential and describe the stages of action potential.
Ionic basis of Action Potential & its Propogation.
Properties of Action Potential.
Types action Potential
Nervous system forms an interconnecting fibers of communication network.
In the ‘hard-wiring’ of the nerves, the signals travel in the form of a flow of electrical current called nerve impulses.
The stimulus-response reactions afford internal constancy in the face of environmental changes.
Heavy metal poisoning is caused by the accumulation of certain metals in the body due to exposure through food, water, industrial chemicals, or other sources. While your body needs small amounts of some heavy metals to function normally — such as zinc, copper, chromium, iron, and manganese — toxic amounts are harmful.
Interpretation of dna typing results and codis Neha Agarwal
An STR genotype is the allele, in the case of a homozygote, or alleles, in the
case of a heterozygote, present in a sample for a particular locus and is normally
reported as the number of repeats present in the allele. A full sample genotype
or STR profi le is produced by the combination of all of the locus genotypes into
a single series of numbers. This profi le is what is entered into a case report or
a DNA database for comparison purposes to other samples.
Sample collection and preservation of biological samplesNeha Agarwal
A preliminary survey should be carried out to evaluate potential evidence. In particular, the
recognition of evidence plays a critical role in solving or prosecuting crimes. The priority of the
potential evidence at crime scenes should be assessed based on each item’s relevance to the solution
of the case. Higher priority should be assigned to evidence with probative value to the case.
For example, the evidence related to a corpus delicti is considered to be of the highest priority.
Corpus delicti is a Latin term meaning “body of crime.” In Western law, it primarily refers to the
principle that in order for an individual to be convicted, it is necessary to prove the occurrence of the crime. In a forensic investigation, it also refers to the physical evidence proving that a crime was committed
Scope and significance of forensic chemistryNeha Agarwal
Forensic chemistry is the application of chemistry and its subfield, forensic toxicology, in a legal setting. A forensic chemist can assist in the identification of unknown materials found at a crime scene.[1] Specialists in this field have a wide array of methods and instruments to help identify unknown substances. These include high-performance liquid chromatography, gas chromatography-mass spectrometry, atomic absorption spectroscopy, Fourier transform infrared spectroscopy, and thin layer chromatography. The range of different methods is important due to the destructive nature of some instruments and the number of possible unknown substances that can be found at a scene. Forensic chemists prefer using nondestructive methods first, to preserve evidence and to determine which destructive methods will produce the best results.
Along with other forensic specialists, forensic chemists commonly testify in court as expert witnesses regarding their findings. Forensic chemists follow a set of standards that have been proposed by various agencies and governing bodies, including the Scientific Working Group on the Analysis of Seized Drugs. In addition to the standard operating procedures proposed by the group, specific agencies have their own standards regarding the quality assurance and quality control of their results and their instruments. To ensure the accuracy of what they are reporting, forensic chemists routinely check and verify that their instruments are working correctly and are still able to detect and measure various quantities of different substances.
Protection of critical information infrastructureNeha Agarwal
Information Infrastructure is the term usually used to describe the totality of inter-connected computers and networks, and information flowing through them. Certain parts of this Information Infrastructure, could be dedicated for management / control etc of infrastructure providers’ e.g. Power generation, Gas/oil pipelines, or support our economy or national
fabric e.g. Banking / Telecom etc. The contribution of the services supported
by these infrastructures, and more importantly, the impact of any sudden
failure or outage on our National well being or National Security marks them as being Critical.
By extension, information infrastructure supporting the operations of Critical Infrastructure (CI) marks this as Critical Information infrastructure (CII). These Networks operate/monitor and control important Governmental and Societal functions and services including, but not limited to, Power (Generation/transmission/ distribution etc), Telecommunication (mobile/landline/internet etc), Transportation (Air/land/rail/sea etc), Defence etc. These CII are becoming increasingly dependent on their information infrastructure for information management, communication and control functions.
“Microbial forensics” has been defined as “a scientific discipline dedicated to analyzing evidence
from a bioterrorism act, biocrime, or inadvertent microorganism/toxin release for attribution
purposes” (Budowle et al., 2003). This emerging discipline is still in the early stages of
development and faces substantial scientific challenges to provide a robust suite of technologies
for identifying the source of a biological threat agent and attributing a biothreat act to a particular
person or group. The unlawful use of biological agents poses substantial dangers to individuals,
public health, the environment, the economies of nations, and global peace. It also is likely that
scientific, political, and media-based controversy will surround any investigation of the alleged
use of a biological agent, and can be expected to affect significantly the role that scientific
information or evidence can play. For these reasons, building awareness of and capacity in
microbial forensics can assist in our understanding of what may have occurred during a biothreat
event, and international collaborations that engage the broader scientific and policy-making
communities are likely to strengthen our microbial forensics capabilities. One goal would be to
create a shared technical understanding of the possibilities—and limitations—of the scientific
bases for microbial forensics analysis._ NCBI
Forensic science utilizes scientific principles to support or negate theories surrounding physical evidence found at a crime scene. As such, forensic scientists analyze evidence gathered or received from crime scenes and present their findings based the results of their analyses.
A forensic science job description may appear distinctly different depending on the area of forensic science being practiced. This is because forensic science is a rather broad field and thus encompasses a number of specialties, all of which are rooted in the natural sciences.
The error (or disturbance) of an observed value is the deviation of the observed value from the (unobservable) true value of a quantity of interest (for example, a population mean), and the residual of an observed value is the difference between the observed value and the estimated value of the quantity of interest (for example, a sample mean).
Suppose there is a series of observations from a univariate distribution and we want to estimate the mean of that distribution (the so-called location model). In this case, the errors are the deviations of the observations from the population mean, while the residuals are the deviations of the observations from the sample mean.
A statistical error (or disturbance) is the amount by which an observation differs from its expected value, the latter being based on the whole population from which the statistical unit was chosen randomly. For example, if the mean height in a population of 21-year-old men is 1.75 meters, and one randomly chosen man is 1.80 meters tall, then the "error" is 0.05 meters; if the randomly chosen man is 1.70 meters tall, then the "error" is −0.05 meters. The expected value, being the mean of the entire population, is typically not observable, and hence the statistical error cannot be observed either.
Most bacteria are free-living organisms that grow by increasing
in mass and then divide by binary fission.
Growth and division are controlled by genes, the expression
of which must be regulated appropriately. Genes
whose activity is controlled in response to the needs of a
cell or organism are called regulated genes. All organisms
also have a large number of genes whose products
are essential to the normal functioning of a growing and
dividing cell, no matter what the conditions are. These
genes are always active in growing cells and are known as
constitutive genes or housekeeping genes; examples include
genes that code for the enzymes needed for protein
synthesis and glucose metabolism. Note that all genes are
regulated on some level. If normal cell function is impaired
for some reason, the expression of all genes, including
constitutive genes, is reduced by regulatory
mechanisms. Thus, the distinction between regulated
and constitutive genes is somewhat arbitrary.
It is over 60 years since Hodgkin and
Huxley1 made the first direct recording of
the electrical changes across the neuronal
membrane that mediate the action
potential. Using an electrode placed inside a
squid giant axon they were able to measure a
transmembrane potential of around 260 mV
inside relative to outside, under resting
conditions (this is called the resting membrane
potential). The action potential is a
transient (,1 millisecond) reversal in the
polarity of this transmembrane potential
which then moves from its point of initiation,
down the axon, to the axon terminals. In a
subsequent series of elegant experiments
Hodgkin and Huxley, along with Bernard
Katz, discovered that the action potential
results from transient changes in the permeability
of the axon membrane to sodium (Na+)
and potassium (K+) ions. Importantly, Na+ and
K+ cross the membrane through independent
pathways that open in response to a change
in membrane potential.
As testimony to their pioneering work, the
fundamental mechanisms described by
Hodgkin, Huxley and Katz remain applicable
to all excitable cells today. Indeed, the
predictions they made about the molecular
mechanisms that might underlie the changes
in membrane permeability showed remarkable
foresight. The molecular basis of the action
potential lies in the presence of proteins
called ion channels that form the permeation
pathways across the neuronal membrane.
Although the first electrophysiological
recordings from individual ion channels were
not made until the mid 1970s,2 Hodgkin and
Huxley predicted many of the properties now
known to be key components of their
function: ion selectivity, the electrical basis
of voltage-sensitivity and, importantly, a
mechanism for quickly closing down the
permeability pathways to ensure that the
action potential only moves along the axon in
one direction.
COMPLEMENT - A group of serum proteins which can be activated (= "fixed") by antigen-antibody complexes or other substances, which may result in lysis of a microbial target, or a variety of other biological effects important in both innate and adaptive immunity. (The majority of these proteins are produced by the liver.)The complex of serum proteins known as COMPLEMENT plays key roles in the lytic and inflammatory properties of antibodies. The CLASSICAL pathway is initiated
by antigen-antibody complexes (via complement components C1, C4, and C2), while the activation of the ALTERNATE pathway (via components B, D and P), and the MBLECTIN ("mannan-binding lectin") pathway may be initiated by other substances independently of adaptive immune responses; all three pathways share those complement components involved in the inflammatory and lytic consequences, namely C3, C5, C6,
C7, C8 and C9. The INFLAMMATION which is a consequence of complement fixation is illustrated by the manifestations of SERUM SICKNESS, and complement is also seen
to be central to the normal process of clearing immune complexes, which is important in preventing IMMUNE COMPLEX DISEASE.
The term river system refers to a ‘river along with its tributaries’.
Based on their source, the Indian River system is classified in to - Himalayan Rivers and Peninsular Rivers.
The Himalayan Rivers, as the name suggests originate from the Himalayas and flow through the Northern Plains.
The major Himalayan River systems are
The Indus River System,
The Ganga River System
The Yamuna River System
The Brahmaputra River System
Peninsular River System or Peninsular Drainage emerges mainly from the Western Ghats. Since the Western Ghats form a ‘water divide’, these rivers either flow eastwards into the Bay of Bengal or into the Arabian Sea towards the west. Peninsular Rivers are basically ‘rain fed’ rivers.
The major Peninsular River Systems are:
Mahanadi
Godavari
Krishna
Cauvery
Drain into Bay of Bengal as they flow eastwards on the plateau and make ‘deltas’ at their mouths; whereas Narmada
Tapti - the west flowing rivers fall into the Arabian Sea and make ‘estuaries’.
not originate in glaciers, but are rain fed rivers. These rivers reduce considerably or dry up during summers.
Sericulture is the silk producing agro-industry
India is the second largest silk producing country in the world after china.
Sericulture or silk farming is the rearing of silkworm for the production of silk
Silk is known as queen of textile and biosteel because of its strength
A Chinese tale of the discovery of the silkworm’s silk was by an ancient empress Lei Zu , the wife of the emperor.
She was drinking tea under tree, when a silk cocoon fell into her tea cup and the hot tea loosened the long strand of silk
As she it out, and started to wrap the silk thread around her flinger, she felt the warm sensation
When silk ran out, an larva appeared. She realized that it was this larva that produces the silk
Soon, she taught this to people and it became wide spread
Echinococcus granulosus, also called hydatid worm belongs to class Cestoda
It causes cystic echinococcosis in livestock and humans being intermediate hosts and parasitize the small intestines of adult canids
It is a zoonotic disease
Definitive hosts are carnivorous predators like dogs, wolves, foxes and lions. While sheep, goat, cattle, pigs and rodents are intermediate hosts. Birds and arthropods act as mechanical vectors
Krebs cycle or tricarboxylic cycle or citric acid cycleNeha Agarwal
The citric acid cycle is the final common pathway for the oxidation of fuel molecules — amino acids, fatty acids, and carbohydrates.
Hans Adolf Krebs. Biochemist; born in Germany. Worked in Britain. His discovery in 1937 of the ‘Krebs cycle’ of chemical reactions was critical to the understanding of cell metabolism and earned him the 1953 Nobel Prize for Physiology or Medicine.
Induced breeding is a technique where organism is stimulated by particular hormone or other synthetic hormone or by providing condition, introduced to breed in captive condition.
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.
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.
(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.
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.
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 .
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.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
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.
2. Communicate
Neurons communicate by means of an electrical
signal called the Action Potential
Action Potentials are based on movements of ions
between the outside and inside of the axon
When an Action Potential occurs, a molecular
message is sent to neighboring neurons
Action Potential is an All or Nothing Process
(like a gun firing)
6. MEMBRANE (Resting)
POTENTIAL
Potential across membrane is called as membrane
potential.
Inside cell: conc. Of potassium ions and organic
compounds is more than outside the cell ( negatively
charged)
Outside cell: concentration of chloride ions and sodium
ions is more than inside the cell (positively charged)
Sodium open/leaky channels: flow of Na+ occurs in
and out of cell
Potassium open/ leaky channels: flow of K+ occurs
in and out of cell
Sodium-potassium pump: voltage gated channel;
allow the efflux of 3 Na+ ions for influx every 2 K+ ions;
7. All the above channels and pump maintains
the resting potential (electro-chemical
gradient) across the membrane i.e. -70 mV
9. DEPOLARISATION
As potential strike -55 mV (threshold potential) , Na+
voltage gated channels open, and allow the influx of
Na+ ions into the cell.
Due to influx of sodium ions, the potential across the
membrane increases.
More increase in potential, more influx of ions
This leads to change in charge across membrane.
Inside_ +vely charged
Outside_ -vely charged
As this potential reaches +40 mV(overshoot), the ,
Na+ voltage gated channels closes, and the , K+
voltage gated channels opens
10. REPOLARISATION
As this potential reaches +40 mV, the , Na+ voltage gated
channels closes, and the , K+ voltage gated channels
opens. This leads to repolarisation
This leads to efflux of potassium ions
Thus the potential across the membrane decrease
Inside_ -vely charged
Outside_ +vely charged
As the potential reaches -70mV, the potassium voltage-
gated channels closes.
However, due to gradual closing of channel, the is some
amount of leaked ions, due to which the potential
decreases below -70mV. This leads to
HYPERPOLARISATION
12. HYPERPOLARISATION AND
REFRACTORY PERIOD
Due to gradual closing of channel, the is some
amount of leaked ions, due to which the potential
decreases below -70mV. This leads to
HYPERPOLARISATION
the refractory period and the axon cannot fire again
until it returns to resting potential (negative polarized
state).
Thus, the membrane undergoes the refractory period.
In the refractory period ,the axon cannot fire again
until it returns to resting potential (negative
polarized state). It lasts for 3-5msec
As the resting potential is restored via open
channels and Na+/K+ pump, new action potential
is fired.
13. • Each spike is followed by a refractory
period.
• An absolute refractory period - it is
impossible to evoke another action potential –
during spike and right after it (Na channels
are open and after that inactivated)
• A relative refractory period - a stronger than
usual stimulus is required to evoke an action
potential (hyperpolarization; part of Na
channels recovered)
14.
15.
16. All-or-None Principle
Throughout depolarisation,
the Na+ continues to rush
inside until the action
potential reaches its peak
and the sodium gates
close.
If the potential cross -55mV ,
then the action potential
will reach to its fate, via
repolarisation and
hyperpolarisation.
If the depolarisation is not
great enough to reach
threshold, then an action
potential and hence an
impulse are not produced.
This is called the All-or-
None Principle.
21. - without the depression (an energy comes from the cell) along
nerve or muscle fibers
- a wave (a spot) of electrical negativity on the surface (electrical
positivity on the internal site of membrane) due to openning
and closing of voltage gated ion channels
Propagation of action potential – local currents
refractoriness
22.
23.
24. 1. Threshold is reached
2. +Na ions enter beginning of
axon
3. this triggers the next Na
gates to open.
4. As they open & allow in Na+,
5. previous gates begin
pumping the Na+ out.
6. Before the action potential
has reached the end, the
beginning of the axon is back
at resting potential & ready for
another firing.