The document discusses dark field microscopy. It begins by explaining that dark field microscopy uses specialized illumination techniques to make otherwise transparent or weakly scattering specimens appear bright against a dark background. It then provides details on the typical components and setup of a dark field microscope, including the use of a condenser with a light stop to focus obliquely angled illumination on the sample. Applications like viewing unstained bacteria, cells, and other small specimens are discussed. Advantages include improved contrast for transparent objects, while disadvantages include lower resolution and sensitivity to dirt or bubbles.
Phase contrast microscopy by sivasangari shanmugam
Phase-contrast microscopy, first described by Dutch physicist Frits Zernike in 1934.
It can be utilized to produce high-contrast images of transparent specimens, such as living cells (usually in culture), microorganisms, thin tissue slices, fibers, latex dispersions, glass fragments, and subcellular particles (including nuclei and other organelles).
DARK FIELD MICROSCOPY by SIVASANGARI SHANMUGAM
Dark-field microscopy is ideally used to illuminate unstained samples causing them to appear brightly lit against a dark background.
This type of microscope contains a special condenser that scatters light and causes it to reflect off the specimen at an angle
Phase contrast microscopy by sivasangari shanmugam
Phase-contrast microscopy, first described by Dutch physicist Frits Zernike in 1934.
It can be utilized to produce high-contrast images of transparent specimens, such as living cells (usually in culture), microorganisms, thin tissue slices, fibers, latex dispersions, glass fragments, and subcellular particles (including nuclei and other organelles).
DARK FIELD MICROSCOPY by SIVASANGARI SHANMUGAM
Dark-field microscopy is ideally used to illuminate unstained samples causing them to appear brightly lit against a dark background.
This type of microscope contains a special condenser that scatters light and causes it to reflect off the specimen at an angle
Dark-field microscopy is used to illuminate unstained samples causing them to appear bright against a dark background. This type of microscope contains a special condenser having a central blacked-out area.
during this ppt of microscopes we will be able to know
INTRODUCTION
DEFINITION
HISTORICAL BACKGROUND
VARIABLES USED IN MICROSCOPY
VARIOUS TYPES OF MICROSCOPES
COMPOUND MICROSCOPE - Structure and Function
USE OF MICROSCOPE
CARE OF MICROSCOPE
defintion
A microscope (Greek: micron = small and scopos = aim)
MICROSCOPE - An instrument for viewing objects that are too small to be seen by the naked or unaided eye
MICROSCOPY - The science of investigating small objects using such an instrument is called microscopy
LIGHT MICROSCOPY by SIVASANGARI SHANMUGAM
The optical microscope, The functions of a light microscope is based on its ability to focus a beam of light through, which is very small and transparent, to produce an image.
Bright field microscopy, Principle and applicationsKAUSHAL SAHU
Introduction
History
Basic Component of Microscope
Light Microscopy
Types of Light Microscopy
What Are Bright Microscopy
Principle of Bright Microscope
Advantage
Disadvantage
Application
Conclusion
Reference
Dark-field microscopy is used to illuminate unstained samples causing them to appear bright against a dark background. This type of microscope contains a special condenser having a central blacked-out area.
during this ppt of microscopes we will be able to know
INTRODUCTION
DEFINITION
HISTORICAL BACKGROUND
VARIABLES USED IN MICROSCOPY
VARIOUS TYPES OF MICROSCOPES
COMPOUND MICROSCOPE - Structure and Function
USE OF MICROSCOPE
CARE OF MICROSCOPE
defintion
A microscope (Greek: micron = small and scopos = aim)
MICROSCOPE - An instrument for viewing objects that are too small to be seen by the naked or unaided eye
MICROSCOPY - The science of investigating small objects using such an instrument is called microscopy
LIGHT MICROSCOPY by SIVASANGARI SHANMUGAM
The optical microscope, The functions of a light microscope is based on its ability to focus a beam of light through, which is very small and transparent, to produce an image.
Bright field microscopy, Principle and applicationsKAUSHAL SAHU
Introduction
History
Basic Component of Microscope
Light Microscopy
Types of Light Microscopy
What Are Bright Microscopy
Principle of Bright Microscope
Advantage
Disadvantage
Application
Conclusion
Reference
Introduction to microscopy
Different parts of a microscope & their function
Different types of microscopy
Different types of optical microscopy
Different types of electron microscopy
Different terms used in microscopy
Staining- Simple, Differential, Special
Gram Staining
The microscope has evolved a lot from the time of Leeuwenhoek. This presentation gives a brief overview about the types of microscope their principle of function and application.
Microscopy is the technique of using microscopes to observe and analyze objects that are too small to be seen by the naked eye. Microscopes are instruments that magnify and resolve the details of objects, allowing scientists and researchers to study the structure, composition, and behavior of materials and specimens at a microscopic level
Microscopy is the technique of using microscopes to observe and analyze objects that are too small to be seen by the naked eye. Microscopes are instruments that magnify and resolve the details of objects, allowing scientists and researchers to study the structure, composition, and behavior of materials and specimens at a microscopic level
Dark-field microscopy is ideally used to illuminate unstained samples causing them to appear brightly lit against a dark background. This type of microscope contains a special condenser that scatters light and causes it to reflect off the specimen at an angle
The pdf contain all the information of various technique ,such as chromatography,spectroscopy,centrifugation,electrophoresis special thanks to Dr.Rambir Singh for helping out the topics easily.Contact for help or suggestion @7985214648 whattapp only
A **bright field microscope** is a type of compound light microscope that illuminates the background against a stained specimen ¹². It is commonly used in practical labs to study organisms' behavior and characteristics such as size, shape, and arrangement ². The microscope uses light rays to produce a dark image against a bright background ¹. It is specially designed with magnifying glasses known as lenses that modify the specimen to produce an image seen through the eyepiece ¹. The bright field microscope is made up of various parts, including the eyepiece, objective lenses, focusing knobs, and stage ¹.
I hope this helps!
Source: Conversation with Bing, 7/11/2023
(1) Brightfield Microscope (Compound Light Microscope)- Definition .... https://microbenotes.com/brightfield-microscope/.
(2) Bright Field Microscopy - Biology Reader. https://biologyreader.com/bright-field-microscopy.html.
(3) Bright-field microscopy - Wikipedia. https://en.wikipedia.org/wiki/Bright-field_microscopy.
(4) Bright Field Microscope: Definition, Parts, Working Principle, Application. https://microbiologynote.com/bright-field-microscope-definition-parts-working-principle-application/.
Bacteria are described in two ways:
Bergey’s Manual of Determinative Bacteriology.
Bergey’s Manual of Systematic Bacteriology.
The bacterial classification is based on 16S RNA sequences
Carl Woese, Oganizes the Domain Bacteria into 18 phyla
Bacterial phyla used in industrial microbiology and biotechnology
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.
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.
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
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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
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This presentation explores a brief idea about the structural and functional attributes of nucleotides, the structure and function of genetic materials along with the impact of UV rays and pH upon them.
Salas, V. (2024) "John of St. Thomas (Poinsot) on the Science of Sacred Theol...Studia Poinsotiana
I Introduction
II Subalternation and Theology
III Theology and Dogmatic Declarations
IV The Mixed Principles of Theology
V Virtual Revelation: The Unity of Theology
VI Theology as a Natural Science
VII Theology’s Certitude
VIII Conclusion
Notes
Bibliography
All the contents are fully attributable to the author, Doctor Victor Salas. Should you wish to get this text republished, get in touch with the author or the editorial committee of the Studia Poinsotiana. Insofar as possible, we will be happy to broker your contact.
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.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
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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
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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
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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,
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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/
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...
Dark field Microscope
1.
2.
3.
4. “It is a technique used to observe unstained
sample causing them to appear brightly against a
dark, purely black background”.
It is one of the simplest and cheapest contrast enhancing
technique and works well for the specimen that have refractive
index which is different from its surrounding medium and
difficult to see.
It is alternative to phase contrast microscope.
In dark field microscope, light seems to radiate from the
specimen while all rest of the field is dark.
5. Only the light scattered by the object enters the
objective that produces a dark background with
sample details appear bright
Specimen suitable for dark field microscope
6. Discovery
Lord Faraday was the first to scientifically
examine the color of small gold particles
Richard Zsigmondy also extensively studied
the properties of nano-particles to developed
ultra microscopy, which is called dark field
microscopy.
7. The dark field microscope creates a contrast between the
object and the surrounding field. The objective and ocular
lenses are used in dark field microscope are same as light
microscope but special condenser is used.
Fallowing steps are Involves:
o First light enters dark field microscope.
o Then a specialized disc_ Light stop, blocks some
light from light source, leaving an outer ring of illumination.
o Condenser Lens focuses the light towards sample.
8. o The light enters the sample, mostly is directly transmitted
while some is scattered from sample.
o The scattered light enters objective lens, while directly
transmitted light simply misses the lens and not collected due
to light stop.
o Only scattered light goes on to produce image while directly
transmitted
light is omitted.
10. The first condenser made
specifically for dark field was
produced by Francis H.
Parabolic glass reflector to create
a hollow cone of light.
Mounted below the microscope
stage.
Made up of two uncorrected lenses.
The top lens of an Abbe dark field
condenser is concave lens.
You can adjust your condenser
for optimal brightness, contrast,
depth of field, etc.
11. “Stops are opaque discs located just under the
bottom lens of the sub-stage condenser”.
When using stops, the aperture need to be opened.
Simplest is a “spider stop” consists of central opaque stop
blocks out the central rays.
This device works fairly well, even with the Abbe condenser
The diameter of the opaque stop should be approximately
16-18 millimeters for a 10x objective of numerical aperture
0.25
12. Individual stops can be interchanged simply by removing
the screw in the bottom of the support spider and replacing
the stop with a new size
13. To achieve a dark field image, it is essential to place a dark
field filter –Patch Stop, into the filter holder of condenser.
The filter prevents light of lamp to directly enter the
objective. The specimen will be illuminated from side and
will scatter some of light to enter the objective so specimen
appears bright on dark background
There are two possibilities to get dark field image.
Using Condenser
Using Dark field filter_ Patch Stop
14.
15. Dark field microscope use in different ways to view variety of
specimens that is hard to see in light field as live bacteria
Dark field microscope often used when specimen is clear or
translucent. Examples are:
Pollen samples.
Live blood samples.
Aquatic environment samples
View everything in liquid sample, debris & all, dark field
microscope is best.
Finding cells in suspension.
For initial examination of suspension of cells
Determination of motility in cultures.
17. Resolution is important to quality of information in an image.
“It is the ability to distinguish two points separate apart
from each other.”
Resolution power of dark field microscope depends on the
number of factors in its construction.
The high resolution of dark field microscope is 0.02μ allows
for easy detection of thin & extremely fragile bacteria as
compared to ordinary light microscope
18. Dark field microscope is a technique creates
contrast in transparent unstained specimens as
living cells.
It depends on controlling specimen
illuminations
Dark field illumination uses a carefully aligned
light source to minimize the quantity of directly
transmitted light entering the image plan,
collecting only light scattered
Dark field can improve image contrast_
particularly transparent objects while
requiring little equipment setup.
Diatom under Rheinberg illumination
19. Fallowing are important applications of dark field microscope:
o Study insects, hairs, fibers, yeast, protozoa as well as some
minerals and crystal etc.
o Research study of live bacterium, as well as mounted cells and
tissues.
o Examining external details, such as outlines, edges, grain
boundaries.
o Viewing blood cells, different types of algae_ Biological Dark
Field Microscope.
o Viewing hairline metal fractures_ Metallurgical dark field
microscope.
o Viewing shrimp or invertebrates_ Stereo Dark field microscope.
o It is specifically use in haematology for examination fresh blood.
20. Used to view transparent, unstained specimens clearly
& examine external of specimen with detail.
High resolution of dark field microscope is allows for
easy detection of thin and fragile specimen.
It provides good results especially through
examination of red blood samples.
It can yield high magnification of living bacteria &
low magnification of tissues, cells of certain
organisms.
Use dark field to study marine organisms
They have simple and economic setup
21.
22. Air bubbles in slide can cause problem & dust and other particles
are readily visible.
Need intense amount of light which can hurt eyes and cause glare.
The internal structure of organisms can’t be studied as light passes
around rather than through organism.
Risk of HIV transmission from infectious specimen.
Lowest resolution in final image & poor depth of field.
Dark field images are prone to degradation, distortion and
inaccuracies.
It is not a reliable tool to obtain accurate measurements of
specimens.
23. J. James,Light Microscopic Techniques in Biology
andMedicine(1976).
M. G. L. Gustafsson, Proc. Natl. Acad. Sci. USA 102,13081
(2005).
V. Poher, H. Zhang, G. Kennedy, C. Griffin, S. Oddos, E. Gu,D.
Elson, M. Girkin, P. French, and M. Dawson, Opt. Express15,
11196 (2007).