This document provides information on staining techniques used in microbiology, including the purpose, procedures, and interpretations of common staining methods. It discusses:
- The purpose of staining is to increase contrast between microorganisms and the background under the microscope.
- Procedures for simple, differential, Gram, and acid-fast (Ziehl-Neelsen) staining are described in detail, including required materials and steps.
- Interpretation of results for each stain is also explained, such as Gram-positive and Gram-negative bacteria appearing different colors.
- Preparation of smears from different specimen types and fixing methods prior to staining is covered.
- Staining methods like Gram staining, acid-fast staining, and Albert's staining are used to enhance contrast in microscopic samples and aid in identification of tissues, cells, and structures.
- Different stains are used depending on the type of sample and desired structures to identify. Stains bind selectively to elements like cell walls, allowing visualization of distinguishing features.
- Proper preparation, staining techniques, and microscopy examination are needed for consistent, repeatable diagnostic analysis. Counterstains may be used to reveal additional details not visible with the primary stain alone.
Identification of bacteria by staining methodsNAGALAKSHMI R
The document discusses the importance of identifying bacteria, including determining clinical significance, guiding patient care, and identifying appropriate antibiotic therapy. It describes various identification methods, including traditional phenotypic methods examining morphology, staining characteristics, and biochemical tests, as well as newer genotypic and molecular methods. Specific staining techniques are explained in detail, including simple staining, differential staining, Gram staining, and acid-fast staining. The staining methods allow visualization of bacteria and differentiation of structures under a microscope.
This document provides information about lab exercises on gram staining, endospore staining, and capsule staining. It includes the procedures for each stain and discusses what structures each stain targets (e.g. gram stain targets the peptidoglycan cell wall). It also provides background on Bacillus anthracis and how it can cause disease. Key points covered are that the gram stain differentiates bacteria types, endospore stain uses malachite green to stain spores, and the capsule stain demonstrates capsules using Congo red and Maneval's solution.
Gram staining is used to classify bacteria based on differences in cell wall composition. It involves staining with crystal violet and iodine, then decolorizing and counterstaining. Gram-positive bacteria retain the crystal violet stain while gram-negative bacteria take up the counterstain. Acid-fast staining is used to identify mycobacteria by using heat to bind primary stain within acid-fast cell walls. Capsule staining uses India ink's dark background to contrast unstained capsules around stained cells. Spore staining employs malachite green and heat to permanently stain endospores within decolorized vegetative cells.
INTRODUCTION TO MICRO LAB, STAINING TECHNIQUES & MORPHOLOGY OF BACTERIADrBhavikapatel
This PPT is helpful to understand first practical to 2nd year MBBS student.
I have added 2 video in this PPT to understand staining techniques properly.
Reference: 1 Gram stain video: Dr.G Bhanu prakash animated medical videos
2. Zn stain video: sridhar Rao
This document discusses various staining techniques used in microscopy to visualize bacteria and other microscopic organisms. It describes different types of stains including simple stains that color all structures the same and differential stains that color different structures differently. Specific staining techniques are explained, including Gram staining to distinguish between Gram-positive and Gram-negative bacteria, acid-fast staining for mycobacteria, and endospore staining. The document provides details on procedures, requirements, and results for common staining methods.
This document discusses various methods for identifying unknown bacterial cultures, including phenotypic, immunological, and genetic techniques. It focuses on morphological identification methods such as staining techniques like simple staining, negative staining, Gram staining, and acid-fast staining. These staining methods allow observation of bacterial size, shape, arrangement and properties to determine the taxon. Identification is important for medical, industrial, and research applications.
This document discusses various methods used to identify unknown bacterial cultures, which is a major responsibility of microbiologists. It outlines staining techniques like Gram staining, acid-fast staining, endospore staining, and capsule staining. These techniques examine morphological characteristics of bacteria like shape, arrangement, presence of spores or capsules. The document also mentions biochemical tests that detect bacterial enzymatic activity or ability to ferment carbohydrates and produce acids/gases. Identifying pathogenic bacteria is important for medical diagnostics and food/brewing industries to prevent contamination.
- Staining methods like Gram staining, acid-fast staining, and Albert's staining are used to enhance contrast in microscopic samples and aid in identification of tissues, cells, and structures.
- Different stains are used depending on the type of sample and desired structures to identify. Stains bind selectively to elements like cell walls, allowing visualization of distinguishing features.
- Proper preparation, staining techniques, and microscopy examination are needed for consistent, repeatable diagnostic analysis. Counterstains may be used to reveal additional details not visible with the primary stain alone.
Identification of bacteria by staining methodsNAGALAKSHMI R
The document discusses the importance of identifying bacteria, including determining clinical significance, guiding patient care, and identifying appropriate antibiotic therapy. It describes various identification methods, including traditional phenotypic methods examining morphology, staining characteristics, and biochemical tests, as well as newer genotypic and molecular methods. Specific staining techniques are explained in detail, including simple staining, differential staining, Gram staining, and acid-fast staining. The staining methods allow visualization of bacteria and differentiation of structures under a microscope.
This document provides information about lab exercises on gram staining, endospore staining, and capsule staining. It includes the procedures for each stain and discusses what structures each stain targets (e.g. gram stain targets the peptidoglycan cell wall). It also provides background on Bacillus anthracis and how it can cause disease. Key points covered are that the gram stain differentiates bacteria types, endospore stain uses malachite green to stain spores, and the capsule stain demonstrates capsules using Congo red and Maneval's solution.
Gram staining is used to classify bacteria based on differences in cell wall composition. It involves staining with crystal violet and iodine, then decolorizing and counterstaining. Gram-positive bacteria retain the crystal violet stain while gram-negative bacteria take up the counterstain. Acid-fast staining is used to identify mycobacteria by using heat to bind primary stain within acid-fast cell walls. Capsule staining uses India ink's dark background to contrast unstained capsules around stained cells. Spore staining employs malachite green and heat to permanently stain endospores within decolorized vegetative cells.
INTRODUCTION TO MICRO LAB, STAINING TECHNIQUES & MORPHOLOGY OF BACTERIADrBhavikapatel
This PPT is helpful to understand first practical to 2nd year MBBS student.
I have added 2 video in this PPT to understand staining techniques properly.
Reference: 1 Gram stain video: Dr.G Bhanu prakash animated medical videos
2. Zn stain video: sridhar Rao
This document discusses various staining techniques used in microscopy to visualize bacteria and other microscopic organisms. It describes different types of stains including simple stains that color all structures the same and differential stains that color different structures differently. Specific staining techniques are explained, including Gram staining to distinguish between Gram-positive and Gram-negative bacteria, acid-fast staining for mycobacteria, and endospore staining. The document provides details on procedures, requirements, and results for common staining methods.
This document discusses various methods for identifying unknown bacterial cultures, including phenotypic, immunological, and genetic techniques. It focuses on morphological identification methods such as staining techniques like simple staining, negative staining, Gram staining, and acid-fast staining. These staining methods allow observation of bacterial size, shape, arrangement and properties to determine the taxon. Identification is important for medical, industrial, and research applications.
This document discusses various methods used to identify unknown bacterial cultures, which is a major responsibility of microbiologists. It outlines staining techniques like Gram staining, acid-fast staining, endospore staining, and capsule staining. These techniques examine morphological characteristics of bacteria like shape, arrangement, presence of spores or capsules. The document also mentions biochemical tests that detect bacterial enzymatic activity or ability to ferment carbohydrates and produce acids/gases. Identifying pathogenic bacteria is important for medical diagnostics and food/brewing industries to prevent contamination.
The document summarizes the Ziehl-Neelsen stain, an acid-fast stain used to identify acid-fast bacteria such as Mycobacteria. It works by using a primary stain, carbol fuchsin, which is retained by acid-fast bacteria after a decolorizing step. This allows acid-fast bacteria to be visualized as red rods against a blue counterstained background. The document discusses the staining procedure, interpretation of results, advantages and limitations of acid-fast staining, and causes of false-positive and false-negative results.
1. The document discusses various staining techniques used to visualize bacterial structures like flagella, capsules, and endospores under a microscope.
2. It describes the Leifson and Ryu staining methods for flagella, which use basic fuchsin and crystal violet dyes respectively. India ink is also discussed for negatively staining capsules against a black background.
3. The most common endospore staining technique mentioned is the Schaeffer-Fulton method, which uses malachite green as the primary stain and safranin as the counterstain to show spores green and vegetative cells red.
1. Gram staining is a differential staining technique developed by Hans Christian Gram in 1884 that is used to classify bacteria into two groups: Gram-positive and Gram-negative.
2. The key steps of Gram staining involve staining with crystal violet dye, treating with iodine, decolorizing with alcohol or acetone, and counterstaining with safranin.
3. Gram-positive bacteria retain the crystal violet dye after decolorization due to their thick peptidoglycan cell wall, while Gram-negative bacteria lose the dye due to their thinner cell wall. This allows bacteria to be classified based on their staining.
This presentation summarizes the technique of Gram staining for bacteria. Gram staining distinguishes between Gram-positive and Gram-negative bacteria based on differences in their cell wall structures. The procedure involves staining a bacterial smear with crystal violet dye, adding iodine as a mordant, decolorizing with alcohol, and counterstaining with safranin. Gram-positive bacteria retain the crystal violet dye and appear purple or blue, while Gram-negative bacteria take up the counterstain and appear red or pink. The presentation outlines the history, principles, staining procedure and reagents, and provides examples of Gram-positive and Gram-negative bacteria.
The document discusses bacterial staining techniques, specifically simple staining and Gram's staining. It begins by explaining how staining enhances contrast under the microscope since bacteria are otherwise invisible. It then describes the basic components and process of simple staining, as well as the principles and steps of Gram's staining technique. Gram's staining allows differentiation of bacteria into Gram-positive or Gram-negative categories based on differences in cell wall structure and composition. This differential staining technique is one of the most common and important in microbiology.
This document discusses various staining techniques used to visualize microorganisms under a microscope. It begins by explaining why staining is necessary since microorganisms cannot be seen with the naked eye. It then covers different types of staining including simple staining, Gram staining, acid-fast staining, negative staining, and specialized staining techniques for flagella, capsules, and spores. Each staining method is described in 1-2 sentences and includes the basic procedure and results.
This document discusses different staining techniques used to visualize bacteria under a microscope. It describes simple staining using single dyes like methylene blue, and differential staining techniques like Gram staining and acid-fast staining. Gram staining differentiates bacteria into Gram-positive and Gram-negative groups based on their ability to retain or lose crystal violet dye. Acid-fast staining is used to identify acid-fast bacteria like Mycobacterium that appear bright red after staining. These staining methods allow clear visualization of bacterial morphology and structure.
This document provides information about staining techniques used in microbiology. It discusses why staining is needed, as structural details of bacteria cannot be seen under a light microscope otherwise. It describes common staining methods like simple stains, negative stains, differential stains, and impregnation methods. Gram staining and Ziehl-Neelsen staining techniques are explained in detail, including the principles, procedures, and uses of each stain. Proper smear preparation and quality are also addressed.
Common Laboratory investigations in dermatologyKezha Zutso
This document provides information on various laboratory investigations used in dermatology, including microscopy techniques, staining methods, and their applications. It discusses optical microscopy, different types of mounts, staining techniques like Gram stain, acid fast staining, Giemsa stain, hematoxylin and eosin stain, periodic acid Schiff stain, Grocott's methenamine silver stain and procedures for performing smears, tissue processing and special stains. The staining methods allow visualization and differentiation of bacteria, fungi and other structures under the microscope for diagnostic purposes.
This document discusses various microbial staining techniques used to visualize microorganisms under a light microscope. It describes simple staining techniques like positive and negative staining that use single stains. It also explains differential staining techniques like Gram staining and acid-fast staining that use multiple stains to differentiate between types of microbes based on cell wall structure. Gram staining distinguishes Gram-positive from Gram-negative bacteria, while acid-fast staining identifies acid-fast bacteria like Mycobacterium that appear bright red due to their waxy cell walls. The document provides detailed procedures and observations for each staining method.
The document discusses several staining techniques used to identify different characteristics of bacteria under a microscope. The Gram stain distinguishes between Gram-positive and Gram-negative bacteria and was an important early technique. The acid-fast stain identifies bacteria with waxy cell walls like Mycobacterium tuberculosis. The endospore stain reveals if a bacteria can form dormant endospores. Capsular staining highlights the capsules of virulent bacteria that are difficult to see with regular stains. Each technique has a specific multi-step procedure to prepare and differentially stain samples for examination.
This document discusses various staining techniques used for microorganisms. It defines staining as using dyes to color biological specimens to aid examination and identification of cells, tissues, and microorganisms. It then describes 7 common staining techniques - simple staining, Gram staining, spore staining, capsule staining, negative staining, acid-fast staining, and fungal staining. For each technique it provides details on the principle, dyes used, procedure, and observations under a microscope. The staining techniques allow differentiation between types of microorganisms based on cell structure.
Mycobacterium tuberculosis (Practical Medical Microbiology, 14)Hussein Al-tameemi
This document discusses Gram positive bacilli, with a focus on Mycobacterium tuberculosis, the causative agent of tuberculosis. Key points:
- M. tuberculosis is a nonmotile, acid-fast, aerobic rod that can be detected using Ziehl-Neelsen staining of sputum smears.
- Sodium hypochlorite treatment followed by centrifugation can be used to concentrate acid-fast bacilli in sputum samples for microscopy.
- M. tuberculosis is cultured on Lowenstein Jensen medium and detected using methods like BACTEC and PCR for rapid diagnosis and drug susceptibility testing.
Staining techniques are used in microbiology to identify bacteria under a microscope. There are several types of staining including simple staining with one dye, Gram staining which differentiates bacteria as Gram-positive or Gram-negative based on cell wall structure, and acid-fast staining used to identify Mycobacterium species. Biochemical tests such as IMViC (Indole, Methyl Red, Voges-Proskauer, Citrate) are also used to identify bacteria based on their metabolic reactions and products.
1. The document discusses different types of microscopes used to observe microorganisms, including brightfield, darkfield, phase-contrast, fluorescence, confocal, transmission electron, and scanning electron microscopes.
2. It also covers different staining techniques used to prepare specimens for microscopy, including simple stains using a single dye, differential stains like Gram staining and acid-fast staining to classify bacteria, and special stains for structures like capsules, endospores, and flagella.
3. Key points are made about classifying bacteria as gram-positive or gram-negative based on their cell wall composition and how they react to staining, as well as how the acid-fast stain is used to
This document provides instructions for performing a Gram stain procedure. The Gram stain allows bacteria to be classified as either Gram-positive or Gram-negative based on differences in their cell wall structure and how they interact with stain reagents. The procedure involves staining a bacterial smear with crystal violet, applying Gram's iodine as a mordant, decolorizing with ethanol or acetone, and counterstaining with safranin. Gram-positive bacteria appear purple or violet while Gram-negative bacteria appear pink or red. The document provides step-by-step instructions for performing the Gram stain and interpreting results under the microscope.
Microscopic examination of bacteria.pptxHARSHITHAKN14
This document summarizes bacterial staining techniques used to identify bacteria under a microscope. It describes simple staining using methylene blue, which stains all bacterial cells, and Gram staining, which differentiates between Gram-positive and Gram-negative bacteria. Gram staining involves staining cells with crystal violet, treating with iodine to fix the stain, washing with ethanol to decolorize Gram-negative cells, and counterstaining all cells with safranin. These staining methods allow observation of bacterial cell shape, size, arrangement, and differentiation between Gram classes for identification and diagnostic purposes.
this presentation involves a comprehensive outlines regarding the most common different methods used in diagnostic microbiology to stain bacteria and their structures
This document discusses different staining techniques used to identify bacteria under a microscope. It describes simple staining which identifies morphological characteristics using a single dye. Negative staining uses an acidic dye to stain the background while leaving unstained bacteria visible. Gram staining differentiates between gram-positive and gram-negative bacteria using multiple stains. Acid-fast staining identifies bacteria with wax-like cell walls that retain dye after acid treatment. These staining methods enhance contrast and visibility of bacteria for analysis under a microscope.
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
The document summarizes the Ziehl-Neelsen stain, an acid-fast stain used to identify acid-fast bacteria such as Mycobacteria. It works by using a primary stain, carbol fuchsin, which is retained by acid-fast bacteria after a decolorizing step. This allows acid-fast bacteria to be visualized as red rods against a blue counterstained background. The document discusses the staining procedure, interpretation of results, advantages and limitations of acid-fast staining, and causes of false-positive and false-negative results.
1. The document discusses various staining techniques used to visualize bacterial structures like flagella, capsules, and endospores under a microscope.
2. It describes the Leifson and Ryu staining methods for flagella, which use basic fuchsin and crystal violet dyes respectively. India ink is also discussed for negatively staining capsules against a black background.
3. The most common endospore staining technique mentioned is the Schaeffer-Fulton method, which uses malachite green as the primary stain and safranin as the counterstain to show spores green and vegetative cells red.
1. Gram staining is a differential staining technique developed by Hans Christian Gram in 1884 that is used to classify bacteria into two groups: Gram-positive and Gram-negative.
2. The key steps of Gram staining involve staining with crystal violet dye, treating with iodine, decolorizing with alcohol or acetone, and counterstaining with safranin.
3. Gram-positive bacteria retain the crystal violet dye after decolorization due to their thick peptidoglycan cell wall, while Gram-negative bacteria lose the dye due to their thinner cell wall. This allows bacteria to be classified based on their staining.
This presentation summarizes the technique of Gram staining for bacteria. Gram staining distinguishes between Gram-positive and Gram-negative bacteria based on differences in their cell wall structures. The procedure involves staining a bacterial smear with crystal violet dye, adding iodine as a mordant, decolorizing with alcohol, and counterstaining with safranin. Gram-positive bacteria retain the crystal violet dye and appear purple or blue, while Gram-negative bacteria take up the counterstain and appear red or pink. The presentation outlines the history, principles, staining procedure and reagents, and provides examples of Gram-positive and Gram-negative bacteria.
The document discusses bacterial staining techniques, specifically simple staining and Gram's staining. It begins by explaining how staining enhances contrast under the microscope since bacteria are otherwise invisible. It then describes the basic components and process of simple staining, as well as the principles and steps of Gram's staining technique. Gram's staining allows differentiation of bacteria into Gram-positive or Gram-negative categories based on differences in cell wall structure and composition. This differential staining technique is one of the most common and important in microbiology.
This document discusses various staining techniques used to visualize microorganisms under a microscope. It begins by explaining why staining is necessary since microorganisms cannot be seen with the naked eye. It then covers different types of staining including simple staining, Gram staining, acid-fast staining, negative staining, and specialized staining techniques for flagella, capsules, and spores. Each staining method is described in 1-2 sentences and includes the basic procedure and results.
This document discusses different staining techniques used to visualize bacteria under a microscope. It describes simple staining using single dyes like methylene blue, and differential staining techniques like Gram staining and acid-fast staining. Gram staining differentiates bacteria into Gram-positive and Gram-negative groups based on their ability to retain or lose crystal violet dye. Acid-fast staining is used to identify acid-fast bacteria like Mycobacterium that appear bright red after staining. These staining methods allow clear visualization of bacterial morphology and structure.
This document provides information about staining techniques used in microbiology. It discusses why staining is needed, as structural details of bacteria cannot be seen under a light microscope otherwise. It describes common staining methods like simple stains, negative stains, differential stains, and impregnation methods. Gram staining and Ziehl-Neelsen staining techniques are explained in detail, including the principles, procedures, and uses of each stain. Proper smear preparation and quality are also addressed.
Common Laboratory investigations in dermatologyKezha Zutso
This document provides information on various laboratory investigations used in dermatology, including microscopy techniques, staining methods, and their applications. It discusses optical microscopy, different types of mounts, staining techniques like Gram stain, acid fast staining, Giemsa stain, hematoxylin and eosin stain, periodic acid Schiff stain, Grocott's methenamine silver stain and procedures for performing smears, tissue processing and special stains. The staining methods allow visualization and differentiation of bacteria, fungi and other structures under the microscope for diagnostic purposes.
This document discusses various microbial staining techniques used to visualize microorganisms under a light microscope. It describes simple staining techniques like positive and negative staining that use single stains. It also explains differential staining techniques like Gram staining and acid-fast staining that use multiple stains to differentiate between types of microbes based on cell wall structure. Gram staining distinguishes Gram-positive from Gram-negative bacteria, while acid-fast staining identifies acid-fast bacteria like Mycobacterium that appear bright red due to their waxy cell walls. The document provides detailed procedures and observations for each staining method.
The document discusses several staining techniques used to identify different characteristics of bacteria under a microscope. The Gram stain distinguishes between Gram-positive and Gram-negative bacteria and was an important early technique. The acid-fast stain identifies bacteria with waxy cell walls like Mycobacterium tuberculosis. The endospore stain reveals if a bacteria can form dormant endospores. Capsular staining highlights the capsules of virulent bacteria that are difficult to see with regular stains. Each technique has a specific multi-step procedure to prepare and differentially stain samples for examination.
This document discusses various staining techniques used for microorganisms. It defines staining as using dyes to color biological specimens to aid examination and identification of cells, tissues, and microorganisms. It then describes 7 common staining techniques - simple staining, Gram staining, spore staining, capsule staining, negative staining, acid-fast staining, and fungal staining. For each technique it provides details on the principle, dyes used, procedure, and observations under a microscope. The staining techniques allow differentiation between types of microorganisms based on cell structure.
Mycobacterium tuberculosis (Practical Medical Microbiology, 14)Hussein Al-tameemi
This document discusses Gram positive bacilli, with a focus on Mycobacterium tuberculosis, the causative agent of tuberculosis. Key points:
- M. tuberculosis is a nonmotile, acid-fast, aerobic rod that can be detected using Ziehl-Neelsen staining of sputum smears.
- Sodium hypochlorite treatment followed by centrifugation can be used to concentrate acid-fast bacilli in sputum samples for microscopy.
- M. tuberculosis is cultured on Lowenstein Jensen medium and detected using methods like BACTEC and PCR for rapid diagnosis and drug susceptibility testing.
Staining techniques are used in microbiology to identify bacteria under a microscope. There are several types of staining including simple staining with one dye, Gram staining which differentiates bacteria as Gram-positive or Gram-negative based on cell wall structure, and acid-fast staining used to identify Mycobacterium species. Biochemical tests such as IMViC (Indole, Methyl Red, Voges-Proskauer, Citrate) are also used to identify bacteria based on their metabolic reactions and products.
1. The document discusses different types of microscopes used to observe microorganisms, including brightfield, darkfield, phase-contrast, fluorescence, confocal, transmission electron, and scanning electron microscopes.
2. It also covers different staining techniques used to prepare specimens for microscopy, including simple stains using a single dye, differential stains like Gram staining and acid-fast staining to classify bacteria, and special stains for structures like capsules, endospores, and flagella.
3. Key points are made about classifying bacteria as gram-positive or gram-negative based on their cell wall composition and how they react to staining, as well as how the acid-fast stain is used to
This document provides instructions for performing a Gram stain procedure. The Gram stain allows bacteria to be classified as either Gram-positive or Gram-negative based on differences in their cell wall structure and how they interact with stain reagents. The procedure involves staining a bacterial smear with crystal violet, applying Gram's iodine as a mordant, decolorizing with ethanol or acetone, and counterstaining with safranin. Gram-positive bacteria appear purple or violet while Gram-negative bacteria appear pink or red. The document provides step-by-step instructions for performing the Gram stain and interpreting results under the microscope.
Microscopic examination of bacteria.pptxHARSHITHAKN14
This document summarizes bacterial staining techniques used to identify bacteria under a microscope. It describes simple staining using methylene blue, which stains all bacterial cells, and Gram staining, which differentiates between Gram-positive and Gram-negative bacteria. Gram staining involves staining cells with crystal violet, treating with iodine to fix the stain, washing with ethanol to decolorize Gram-negative cells, and counterstaining all cells with safranin. These staining methods allow observation of bacterial cell shape, size, arrangement, and differentiation between Gram classes for identification and diagnostic purposes.
this presentation involves a comprehensive outlines regarding the most common different methods used in diagnostic microbiology to stain bacteria and their structures
This document discusses different staining techniques used to identify bacteria under a microscope. It describes simple staining which identifies morphological characteristics using a single dye. Negative staining uses an acidic dye to stain the background while leaving unstained bacteria visible. Gram staining differentiates between gram-positive and gram-negative bacteria using multiple stains. Acid-fast staining identifies bacteria with wax-like cell walls that retain dye after acid treatment. These staining methods enhance contrast and visibility of bacteria for analysis under a microscope.
Or: Beyond linear.
Abstract: Equivariant neural networks are neural networks that incorporate symmetries. The nonlinear activation functions in these networks result in interesting nonlinear equivariant maps between simple representations, and motivate the key player of this talk: piecewise linear representation theory.
Disclaimer: No one is perfect, so please mind that there might be mistakes and typos.
dtubbenhauer@gmail.com
Corrected slides: dtubbenhauer.com/talks.html
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Current Ms word generated power point presentation covers major details about the micronuclei test. It's significance and assays to conduct it. It is used to detect the micronuclei formation inside the cells of nearly every multicellular organism. It's formation takes place during chromosomal sepration at metaphase.
Remote Sensing and Computational, Evolutionary, Supercomputing, and Intellige...University of Maribor
Slides from talk:
Aleš Zamuda: Remote Sensing and Computational, Evolutionary, Supercomputing, and Intelligent Systems.
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Inter-Society Networking Panel GRSS/MTT-S/CIS Panel Session: Promoting Connection and Cooperation
https://www.etran.rs/2024/en/home-english/
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
hematic appreciation test is a psychological assessment tool used to measure an individual's appreciation and understanding of specific themes or topics. This test helps to evaluate an individual's ability to connect different ideas and concepts within a given theme, as well as their overall comprehension and interpretation skills. The results of the test can provide valuable insights into an individual's cognitive abilities, creativity, and critical thinking skills
The debris of the ‘last major merger’ is dynamically youngSérgio Sacani
The Milky Way’s (MW) inner stellar halo contains an [Fe/H]-rich component with highly eccentric orbits, often referred to as the
‘last major merger.’ Hypotheses for the origin of this component include Gaia-Sausage/Enceladus (GSE), where the progenitor
collided with the MW proto-disc 8–11 Gyr ago, and the Virgo Radial Merger (VRM), where the progenitor collided with the
MW disc within the last 3 Gyr. These two scenarios make different predictions about observable structure in local phase space,
because the morphology of debris depends on how long it has had to phase mix. The recently identified phase-space folds in Gaia
DR3 have positive caustic velocities, making them fundamentally different than the phase-mixed chevrons found in simulations
at late times. Roughly 20 per cent of the stars in the prograde local stellar halo are associated with the observed caustics. Based
on a simple phase-mixing model, the observed number of caustics are consistent with a merger that occurred 1–2 Gyr ago.
We also compare the observed phase-space distribution to FIRE-2 Latte simulations of GSE-like mergers, using a quantitative
measurement of phase mixing (2D causticality). The observed local phase-space distribution best matches the simulated data
1–2 Gyr after collision, and certainly not later than 3 Gyr. This is further evidence that the progenitor of the ‘last major merger’
did not collide with the MW proto-disc at early times, as is thought for the GSE, but instead collided with the MW disc within
the last few Gyr, consistent with the body of work surrounding the VRM.
When I was asked to give a companion lecture in support of ‘The Philosophy of Science’ (https://shorturl.at/4pUXz) I decided not to walk through the detail of the many methodologies in order of use. Instead, I chose to employ a long standing, and ongoing, scientific development as an exemplar. And so, I chose the ever evolving story of Thermodynamics as a scientific investigation at its best.
Conducted over a period of >200 years, Thermodynamics R&D, and application, benefitted from the highest levels of professionalism, collaboration, and technical thoroughness. New layers of application, methodology, and practice were made possible by the progressive advance of technology. In turn, this has seen measurement and modelling accuracy continually improved at a micro and macro level.
Perhaps most importantly, Thermodynamics rapidly became a primary tool in the advance of applied science/engineering/technology, spanning micro-tech, to aerospace and cosmology. I can think of no better a story to illustrate the breadth of scientific methodologies and applications at their best.
ESPP presentation to EU Waste Water Network, 4th June 2024 “EU policies driving nutrient removal and recycling
and the revised UWWTD (Urban Waste Water Treatment Directive)”
Phenomics assisted breeding in crop improvementIshaGoswami9
As the population is increasing and will reach about 9 billion upto 2050. Also due to climate change, it is difficult to meet the food requirement of such a large population. Facing the challenges presented by resource shortages, climate
change, and increasing global population, crop yield and quality need to be improved in a sustainable way over the coming decades. Genetic improvement by breeding is the best way to increase crop productivity. With the rapid progression of functional
genomics, an increasing number of crop genomes have been sequenced and dozens of genes influencing key agronomic traits have been identified. However, current genome sequence information has not been adequately exploited for understanding
the complex characteristics of multiple gene, owing to a lack of crop phenotypic data. Efficient, automatic, and accurate technologies and platforms that can capture phenotypic data that can
be linked to genomics information for crop improvement at all growth stages have become as important as genotyping. Thus,
high-throughput phenotyping has become the major bottleneck restricting crop breeding. Plant phenomics has been defined as the high-throughput, accurate acquisition and analysis of multi-dimensional phenotypes
during crop growing stages at the organism level, including the cell, tissue, organ, individual plant, plot, and field levels. With the rapid development of novel sensors, imaging technology,
and analysis methods, numerous infrastructure platforms have been developed for phenotyping.
BREEDING METHODS FOR DISEASE RESISTANCE.pptxRASHMI M G
Plant breeding for disease resistance is a strategy to reduce crop losses caused by disease. Plants have an innate immune system that allows them to recognize pathogens and provide resistance. However, breeding for long-lasting resistance often involves combining multiple resistance genes
3. • Bacteria are microscopic organisms. They
are also colorless for the most part. In order
to visualize them to study their structure,
shape and other structural characteristics, it
becomes necessary to make them more
easily visible.
• This means that the structures have to be
contrasted from their environment so that
they can be seen easily.
4. • The purpose of staining is to increase the
contrast between the organisms and the
background so that they are more readily seen
in the light microscope.
5. • Simple staining: A stain which provides color
contrast but gives same color to all bacteria.
Ex: Loeffler’s methylene blue, Diluted carbol
fuchsin.
• Differential staining: A stain which imparts
different colors to different bacteria(which
contains more than one stain).
EX: Gram’s stain, Acid fast stain, Special stains.
6. How to prepare and fix smears prior
to staining
• If smears are to provide reliable information
they must be prepared, labelled, and fixed
correctly prior to being stained.
• Every slide must be labelled clearly with the
date and the patient’s name and number.
7. How to make smears
• Smears should be spread evenly covering an
area of about 15–20 mm diameter on a slide.
• The techniques used to make smears from
different specimens are as follows:
8. Purulent specimen: Using a sterile wire loop,
make a thin preparation. Do not centrifuge a
purulent fluid, e.g. c.s.f. containing pus cells.
Non-purulent fluid specimen: Centrifuge the
fluid and make a smear from a drop of the
well-mixed sediment, e.g. direct smear from
urine or other biological fluids.
9. Sputum for gram stain: Use a piece of clean
stick to transfer and spread purulent and
caseous material on a slide.
Culture: Emulsify a colony in sterile distilled
water and make a thin preparation on a slide.
When a broth culture, transfer a loopful to a
slide and make a thin preparation.
10. Swabs: Roll the swab on a slide. This is
particularly important when looking for
intracellular bacteria such as N. gonorrhoeae
(urethral, cervical, or eye swab). Rolling the
swab avoids damaging the pus cells.
Faeces: Use a piece of clean stick to transfer
pus and mucus to a slide.
11.
12.
13. Drying and fixing smears
• After making a smear, leave the slide in a safe
place for the smear to air-dry.
• The purpose of fixation is to preserve
microorganisms and to prevent smears being
washed from slides during staining.
14. • Smears are fixed by heat, alcohol, or
occasionally by other chemicals.
• Heat fixation: This is widely used but can
damage organisms and alter their staining
reactions especially when excessive heat is
used.
15. • When used, heat fixation must be carried out
with care. The following technique is
recommended:
o 1- Allow the smear to air-dry completely.
o 2- Rapidly pass the slide, smear uppermost,
three times through the flame of a spirit lamp
or pilot flame of a Bunsen burner.
o 3- Allow the smear to cool before staining it.
16. • Heat fixation also damages leucocytes and is
therefore unsuitable for fixing smears which
may contain intracellular organisms such as N.
gonorrhoeae and N. meningitidis.
17. • Alcohol fixation: This form of fixation is far less
damaging to microorganisms than heat. Cells,
especially pus cells, are also well preserved.
• Alcohol fixation is therefore recommended for
fixing smears when looking for Gram negative
intracellular diplococc.
18. Precautions to take when staining
smears
1. Use a staining rack. Do not immerse slides in
containers of stain because this can lead to
contamination of stains and transfer of organisms
from one smear to another.
2. Do not attempt to stain a smear that is too thick.
This is one of the commonest causes of poor
staining and incorrect reporting of smears.
19. 3. Label clearly stains and reagents.
4. When washing smears of CSF sediment and
other specimens which can be easily washed
from a slide, direct the water from a wash
bottle on the back of the slide, not directly
on the smear.
20. 5. After staining, place the slides at an angle in
a draining rack for the smears to air-dry.
6. To check staining results, use quality control
smears of organisms, particularly when a
new batch of stain is used.
21. Gram stain technique
• The Gram staining reaction is used to help identify
pathogens in specimens and cultures by their Gram
reaction (Gram positive or Gram negative) and
morphology.
1. Crystal violet stain.
2. Lugol’s iodine Reagent.
3. Acetone–alcohol decolorizer.
4. Safranin (counter stain).
22. Gram positive bacteria
• Stain dark purple with crystal violet and are
not decolorized by acetone or ethanol.
Examples include species of: Staphylococcus,
Streptococcus.
23. Gram negative bacteria
• Stain red because after being stained with
crystal violet they are decolorized by acetone
or ethanol and take up the red counterstain.
Examples include species of: Neisseria,
Klebsiella, Salmonella, Shigella.
24.
25.
26. Steps of gram stain
1. Cover the fixed smear with crystal violet stain
for 30–60 seconds.
2. Rapidly wash off the stain with clean water.
Note: When the tap water is not clean, use
filtered water or clean boiled rainwater.
3. Tip off all the water, and cover the smear with
Lugol’s iodine for 30–60 seconds.
4. Wash off the iodine with clean water.
5. Decolorize rapidly (few seconds) with acetone–
alcohol. Wash immediately with clean water.
27. 6. Cover the smear with Safranin (counter stain)
for 2 minutes.
7. Wash off the stain with clean water.
8. Wipe the back of the slide clean, and place it
in a draining rack for the smear to air-dry.
9. Examine the smear microscopically with the
oil immersion objective to report the bacteria
and cells.
28.
29. Interpretation of gram stains
Results:
• Gram positive bacteria . . . . . . . . . . . . Dark purple
• Yeast cells (Candida) . . . . . . . . . . . . . Dark purple
• Gram negative bacteria . . . . . . . . Pale to dark red
• Nuclei of pus cells . . . . . . . . . . . . . . . . . . . . . . Red
• Epithelial cells . . . . . . . . . . . . . . . . . . . . . . Pale red
30. Reporting gram smears:
The report should include the following information:
Numbers of bacteria present, whether many,
moderate, few, or scanty.
Gram reaction of the bacteria, whether Gram
positive or Gram negative.
Morphology of the bacteria, whether cocci,
diplococci, streptococci, rods, or coccobacilli.
Presence and number of pus cells.
Presence of yeast cells and epithelial cells.
31.
32.
33.
34.
35.
36.
37.
38. Variations in Gram reactions
Gram positive organisms may lose their
ability to retain crystal violet and stain
Gram negatively for the following
reasons:
Cell wall damage due to antibiotic
therapy or excessive heat-fixation of the
smear.
Over-decolorization of the smear.
39. Use of an iodine solution which is too old, i.e.
yellow instead of brown in colour (always
store in a brown glass or other light opaque
container).
Smear has been prepared from an old culture.
Gram negative organisms may not be
fully decolorized and appear as Gram
positive when a smear is too thick.
40. Control of gram stain
Always check new batches of stain and
reagents for correct staining reactions using a
smear containing known Gram positive and
Gram negative organisms.
42. • The Ziehl-Neelsen (Zn) technique is used to
stain Mycobacterium species including M.
tuberculosis, M.ulcerans, and M. leprae.
• Mycobacteria, unlike most other bacteria, do
not stain well by the Gram technique.
• They can however be stained with carbol
fuchsin combined with phenol. The stain binds
to the mycolic acid in the mycobacterial cell
wall.
43. • After staining, an acid decolorizing
solution is applied. This removes the red
dye from the background cells, tissue
fibres, and any organisms in the smear
except mycobacteria which retain (hold
fast to) the dye and are therefore
referred to as acid fast bacilli, or simply
AFB.
44. • Following decolorization, the smear is
counter stained with methylene blue
which stains the background material,
providing a contrast color against which
the red AFB can be seen.
45.
46. Preparation and fixation of the smear for
the detection of M. tuberculosis
Sputum for Z.N. stain:
The specimen must be sputum, not saliva.
Sputum is best collected in the morning soon
after the patient wakes and before any mouth-
wash is used.
When pulmonary tuberculosis is suspected,
up to three specimens may need to be
examined to detect AFB.
47. The chances of detecting AFB in sputum
smears are significantly increased when
sputum is first treated with 5% sodium
hypochlorite (NaOC1), i.e. bleach,
followed by centrifugation.
NaOC1 treated sputum cannot be used
for culture.
48. Sodium hypochlorite centrifugation technique to
concentrate AFB
Transfer 1–2 ml of sputum (particularly that
which contains any yellow caseous material)
to a sterile container.
Add an equal volume of concentrated sodium
hypochlorite (bleach) solution and mix well.
Leave at room temperature for 10–15
minutes,
49. shaking at intervals to break down the
mucus in the sputum.
Add about 8 ml of distilled water, Mix well.
Centrifuge at 3000 g for 15 minutes.
Using a pipette, remove and discard the
supernatant fluid. Mix the sediment.
50. Transfer a drop of the well-mixed sediment to
a clean scratch-free glass slide.
Spread the sediment to make a thin
preparation and allow to air-dry.
Heat-fix the smear and stain it using the Ziehl-
Neelsen technique.
51.
52. Preparation of other samples for Z.N. stain:
o Non-purulent fluid specimen: Centrifuge the
fluid and make a smear from a drop of the well-
mixed sediment, (Do not centrifuge a purulent
fluid).
o e.g.
CSF when tuberculosis meningitis is suspected.
Effusions samples when tuberculosis is suspected
e.g. (Pleural, Pericardial, peritoneal, and Synovial
Fluids).
55. 1. Cover the fixed smear with carbol fuchsin
stain.
2. Heat the stain until vapour just begins to rise
(i.e. about 60 C). Do not overheat. Allow the
heated stain to remain on the slide for 5
minutes.
3. Wash off the stain with clean water.
4. Cover the smear with 3% v/v acid alcohol for
5 minutes or until the smear is sufficiently
decolorized, i.e. pale pink.
56. 5. Wash well with clean water.
6. Cover the smear with Methylene blue stain
for 1–2 minutes.
7. Wash off the stain with clean water.
8. Wipe the back of the slide clean, and place it
in a draining rack for the smear to air-dry (do
not blot dry).
9. Examine the smear microscopically for AFB,
using the 100X oil immersion objective.
10. AFB will stain bright red, and the
background will stain blue.
63. Reporting of sputum smears:
• When any definite red bacilli are seen, report
the smear as ‘AFB positive’, and give an
indication of the number of bacteria present
as follows:
• More than 10 AFB/field . . . . report +++
• 1–10 AFB/field . . . . . . . . . . . report ++
• 10–100 AFB/100 fields . . . . . report +
• 1–9 AFB/100 fields . . . . .report the exact
number.
64. When no AFB are seen after examining 100
fields:
Report the smear as ‘No AFB seen’. Do not
report ‘Negative’ because organisms may be
present but not seen in those fields examined.
Up to three specimens (one collected as an early
morning specimen) may need to be examined to
detect M. tuberculosis in sputum.
65. When very few AFB are seen: e.g. when only
one or two AFB are seen, request a further
specimen to examine.
Tap water and deionized water (using ‘old’
resin) sometimes contain AFB that resemble
tubercle bacilli, and occasionally stained
scratches on a slide can be mistaken for AFB.
Occasionally AFB can be transferred from one
smear to another when the same piece of
blotting paper is used to dry several smears.
66. Quality control of Ziehl-Neelsen stain
At regular intervals, and always when a
new batch of stain is started, two sputum
smears of known high and low AFB
positivity should be stained with the
routine smears to check that the carbol
fuchsin, staining method, and the
microscopical examination of smears are
satisfactory.