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See all Premium member Presentation Transcript Forensic Science : Forensic Science By Maria saleem Gc. University.fsd Pakistan What is Forensic science? : What is Forensic science? Forensic Science is the application of science to law Any branch of science used in the resolution of legal disputes is forensic science Multidisciplinary science including biology, chemistry, medicine, physics, geology, computer science and psychology. What does forensic means? : What does forensic means? The word comes from Latin word forēnsis, which means "relating to a public forum’’ used in a court of law Forensic serologists examine body fluids, firearms technicians classify and test firearms and explosives, and forensic chemists determine the composition and identity of materials. Evidence and trace examination : Evidence and trace examination Analysis of crime scene Recongnition of crime scene and cover up the area at which crime occurred You have to sniff things out to be a good investigator! Continued : Continued Crime Scene Documentation Creation of visual record that will allow the forensics lab to easily recreate an accurate view of the scene Apparatus used for this may be digital camera, lenses, flashes, pens, graphpapers, pencils , sketch pad etc continued : continued collection of evidences Trace evidence (gunshot residue, paint residue, broken glass, unknown chemicals, drugs) Impressions (fingerprints, footwear, tool marks) Body fluids (blood, saliva, vomit) Slide 7: Hair and fibers Weapons and firearms evidence (knives, guns, bullet holes) Questioned documents (diaries, suicide note, phone books; also includes electronic documents like answering machines) Examining the body : Examining the body Stains or marks on the clothing Bruises, cuts or marks on body Defense injuries Anything missing e.g ring etc Insect activiy on body Trace evidence : Gunshot residue (GSR) Burned powder contain traces of nitrites Both chemical reactions and microscopic analysis (including electron microscopy) are employed in the identification of powder residues on clothes and skin. Trace evidence An early method for detecting gunshot residue : An early method for detecting gunshot residue on the hands of suspects involved coating the hand with melted paraffin , allowing the paraffin to cool, and then stripping it off. Gunshot residues transferred from skin to paraffin turned blue or green in the presence of diphenylamine. The Greiss reagent is much more definitive, and additional tests can identify traces of lead around bullet holes. Search patterns: Inward spiral : Search patterns: Inward spiral Outward spiral : Outward spiral Parallel patern : Parallel patern Grid pattern : Grid pattern Zone pattern : Zone pattern Chemistry in crime scenes : Chemistry in crime scenes Involves analysis of drugs, explosives or unknown chemicals Sealing of physical evidences in special containers to prevent contamination and degradation and is catalogued carefully Forensic chemist specialize in specific area. An array of techniques used in forensic lab : An array of techniques used in forensic lab Infra red Ultravoilet and visible spectroscopy Mass spectrometery Gas chromatography HPLC Atomic absorbtion spectroscopy Selection of technique depends upon sample. : Often analyzed samples are not pure May be mixture of compounds Can be separated into components by using techniques Analytical Techniques and Instrumentation : Analytical Techniques and Instrumentation Gas chromatography separates out volatile substances into individual components. Mass spectrometer connected with gc column separates ionized sample with charge to mass ratio. Nuclear magnetic resonance spectrophotometry (NMR) makes use of the fact that nuclei of some molecules absorb radio frequency radiation in strong magnetic fields. Nuclei in certain molecules absorb radiation at characteristic frequencies, making the identification of even tiny or impure samples possible X-ray analysis allows the forensic investigator to visualize foreign objects within the body. continued : continued Infrared spectrophotometry is especially useful for the identification of organic compounds, as bonds between certain atoms readily absorb infrared radiation Ultraviolet (UV) spectrophotometry helps distinguish between samples of proteins and nucleic acids such as deoxyribonucleic acid (DNA) Slide 21: Atomic absorption spectrophotometry provides ways of determining absorption and emission spectra, useful tools in the analysis of metals such as bullet fragments Toxicology : Toxicology Toxicologists examine a wide range of materials such as blood stains urine blood gases for traces of poisons or drugs. Insects found on or near corpses are also collected and examined. Testing for alcohol : Testing for alcohol Breathalyzer kit is standard equipment to estimate the blood alcohol content. the concentration of ethanol in the breath bears a definite relationship to its concentration in blood. Many communities have now set a legal limit of 0.08 percent in blood a person's driving ability is affected at a blood ethanol level of 0.05 percent. Slide 24: Several types of analytic devices infrared spectrophotometer, the most common test of oxidation of alcohols Method for oxidation of alcohols : Method for oxidation of alcohols The person being tested blows through a tube, which bubbles the breath through a solution of chemicals containing sulfuric acid, potassium dichromate, water. Oxidation of the alcohol results in the reduction of dichromate ion to chromic ion, with a corresponding change in color from orange to green. Slide 26: An electrical device employing a photocell compares the color of the test solution with a standard solution, giving a quantitative determination of the alcohol content. The test provides a quick and reproducible determination of the amount of alcohol in a person's breath and is a numerical measure of the amount of alcohol in the bloodstream Finger printing : Finger printing the science of fingerprinting is still commonly used as a form of identification “dactylography” which can not only prove that a person was present at a crime scene, but can also be used to compare with the stored fingerprints of millions of other known criminals. History of finger printing : History of finger printing Sir Francis Galton introduced fingerprints as a form of identification. ‘icnofalagometrico' an early fingerprinting filing system Fingerprints follow 3 fundamental principles : Fingerprints follow 3 fundamental principles A fingerprint is an individual characteristic; no two people have been found with the exact same fingerprint pattern. A fingerprint pattern will remain unchanged for the life of an individual;. Fingerprints have general characteristic ridge patterns that allow them to be systematically identified. Revealing of latent finger prints : Revealing of latent finger prints Prints may be collected by revealing them with a dusting of black powder and then lifted with a piece of clear tape. Slide 31: Some investigators use fluorescent powder and UV lights to help them find latent prints on multi-colored or dark surfaces. Magnetic powder can also be used to reveal latent prints. This type of powder works better on shiny surfaces or plastic baggies or containers. Slide 32: The cyanoacrylate fuming method (often called the super glue method) is a procedure that is used to develop latent fingerprints on a variety of objects. Patterns of finger prints : Patterns of finger prints Loop type pattern : Loop type pattern Whorl type pattern : Whorl type pattern Whorl type pattern : Whorl type pattern Whorl type pattern : Whorl type pattern DNA profiling : DNA profiling It is a method of identifying an individual by unique characteristics of that person’s DNA Historical background : Historical background DNA fingerprinting was developed in 1984 by Alec. J. Jeffrey at the University of Leicester He was studying the gene of myoglobin. Steps of DNA profiling : Steps of DNA profiling RFLP (restriction fragments length polymerase) 1st step: cells are broken down to release DNA 2nd step: DNA is cut into pieces by restriction enzymes 3rd step: Place fragments into one end of a bed of agarose gel with electrodes in it. Slide 44: 4. Use an electric current to sort the DNA segments by length. This process is called agarose gel electrophoresis. Electrophoresis refers to the process of moving the negatively-charged molecules through the gel with electricity. Shorter segments move farther away from their original location, while longer ones stay closer. The segments align in parallel rows. Other techniques of DNA profiling : Other techniques of DNA profiling variable number of tandem repeats (VNTR's ) PCR analysis ( polymerase chain reaction) STR analysis ( short tandem repeats) Slide 47: Thanks You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.
forensic science maria_saleem2007 Download Post to : URL : Related Presentations : Share Add to Flag Embed Email Send to Blogs and Networks Add to Channel Uploaded from authorPOINT lite Insert YouTube videos in PowerPont slides with aS Desktop Copy embed code: (To copy code, click on the text box) Embed: URL: Thumbnail: WordPress Embed Customize Embed The presentation is successfully added In Your Favorites. Views: 915 Category: Science & Tech.. License: All Rights Reserved Like it (0) Dislike it (0) Added: July 15, 2010 This Presentation is Public Favorites: 2 Presentation Description it is useful presentation to understand about forensic science and initial events by CSi officers to resolve the crime Comments Posting comment... By: rajeshkittu (14 month(s) ago) Can I unload the wonderful presentation made by you for the learning process. rajesh forensic Expert Saving..... Post Reply Close By: maria_saleem2007 (14 month(s) ago) yes now you can download. Saving..... Edit Comment Close By: ramvijay (17 month(s) ago) ram_vijay1982@yahoo.co.in, thanks Saving..... Post Reply Close Saving..... Edit Comment Close By: neilgirl (17 month(s) ago) can i download this presentation please? Saving..... Post Reply Close Saving..... Edit Comment Close By: leo_mz87 (18 month(s) ago) hi i need this presentation because i have a seminar soon .. can i have it ?? Saving..... Post Reply Close By: maria_saleem2007 (17 month(s) ago) i donot know how can this presentation available for download?if you know then tell me. Saving..... Edit Comment Close By: ramvijay (18 month(s) ago) Plz send me this power point presentation, which may be useful to me and my students. weating for your response. thanks Saving..... Post Reply Close By: maria_saleem2007 (17 month(s) ago) ok i will send you. kindly give your yahoo or hotmail id. Saving..... Edit Comment Close loading.... See all Premium member Presentation Transcript Forensic Science : Forensic Science By Maria saleem Gc. University.fsd Pakistan What is Forensic science? : What is Forensic science? Forensic Science is the application of science to law Any branch of science used in the resolution of legal disputes is forensic science Multidisciplinary science including biology, chemistry, medicine, physics, geology, computer science and psychology. What does forensic means? : What does forensic means? The word comes from Latin word forēnsis, which means "relating to a public forum’’ used in a court of law Forensic serologists examine body fluids, firearms technicians classify and test firearms and explosives, and forensic chemists determine the composition and identity of materials. Evidence and trace examination : Evidence and trace examination Analysis of crime scene Recongnition of crime scene and cover up the area at which crime occurred You have to sniff things out to be a good investigator! Continued : Continued Crime Scene Documentation Creation of visual record that will allow the forensics lab to easily recreate an accurate view of the scene Apparatus used for this may be digital camera, lenses, flashes, pens, graphpapers, pencils , sketch pad etc continued : continued collection of evidences Trace evidence (gunshot residue, paint residue, broken glass, unknown chemicals, drugs) Impressions (fingerprints, footwear, tool marks) Body fluids (blood, saliva, vomit) Slide 7: Hair and fibers Weapons and firearms evidence (knives, guns, bullet holes) Questioned documents (diaries, suicide note, phone books; also includes electronic documents like answering machines) Examining the body : Examining the body Stains or marks on the clothing Bruises, cuts or marks on body Defense injuries Anything missing e.g ring etc Insect activiy on body Trace evidence : Gunshot residue (GSR) Burned powder contain traces of nitrites Both chemical reactions and microscopic analysis (including electron microscopy) are employed in the identification of powder residues on clothes and skin. Trace evidence An early method for detecting gunshot residue : An early method for detecting gunshot residue on the hands of suspects involved coating the hand with melted paraffin , allowing the paraffin to cool, and then stripping it off. Gunshot residues transferred from skin to paraffin turned blue or green in the presence of diphenylamine. The Greiss reagent is much more definitive, and additional tests can identify traces of lead around bullet holes. Search patterns: Inward spiral : Search patterns: Inward spiral Outward spiral : Outward spiral Parallel patern : Parallel patern Grid pattern : Grid pattern Zone pattern : Zone pattern Chemistry in crime scenes : Chemistry in crime scenes Involves analysis of drugs, explosives or unknown chemicals Sealing of physical evidences in special containers to prevent contamination and degradation and is catalogued carefully Forensic chemist specialize in specific area. An array of techniques used in forensic lab : An array of techniques used in forensic lab Infra red Ultravoilet and visible spectroscopy Mass spectrometery Gas chromatography HPLC Atomic absorbtion spectroscopy Selection of technique depends upon sample. : Often analyzed samples are not pure May be mixture of compounds Can be separated into components by using techniques Analytical Techniques and Instrumentation : Analytical Techniques and Instrumentation Gas chromatography separates out volatile substances into individual components. Mass spectrometer connected with gc column separates ionized sample with charge to mass ratio. Nuclear magnetic resonance spectrophotometry (NMR) makes use of the fact that nuclei of some molecules absorb radio frequency radiation in strong magnetic fields. Nuclei in certain molecules absorb radiation at characteristic frequencies, making the identification of even tiny or impure samples possible X-ray analysis allows the forensic investigator to visualize foreign objects within the body. continued : continued Infrared spectrophotometry is especially useful for the identification of organic compounds, as bonds between certain atoms readily absorb infrared radiation Ultraviolet (UV) spectrophotometry helps distinguish between samples of proteins and nucleic acids such as deoxyribonucleic acid (DNA) Slide 21: Atomic absorption spectrophotometry provides ways of determining absorption and emission spectra, useful tools in the analysis of metals such as bullet fragments Toxicology : Toxicology Toxicologists examine a wide range of materials such as blood stains urine blood gases for traces of poisons or drugs. Insects found on or near corpses are also collected and examined. Testing for alcohol : Testing for alcohol Breathalyzer kit is standard equipment to estimate the blood alcohol content. the concentration of ethanol in the breath bears a definite relationship to its concentration in blood. Many communities have now set a legal limit of 0.08 percent in blood a person's driving ability is affected at a blood ethanol level of 0.05 percent. Slide 24: Several types of analytic devices infrared spectrophotometer, the most common test of oxidation of alcohols Method for oxidation of alcohols : Method for oxidation of alcohols The person being tested blows through a tube, which bubbles the breath through a solution of chemicals containing sulfuric acid, potassium dichromate, water. Oxidation of the alcohol results in the reduction of dichromate ion to chromic ion, with a corresponding change in color from orange to green. Slide 26: An electrical device employing a photocell compares the color of the test solution with a standard solution, giving a quantitative determination of the alcohol content. The test provides a quick and reproducible determination of the amount of alcohol in a person's breath and is a numerical measure of the amount of alcohol in the bloodstream Finger printing : Finger printing the science of fingerprinting is still commonly used as a form of identification “dactylography” which can not only prove that a person was present at a crime scene, but can also be used to compare with the stored fingerprints of millions of other known criminals. History of finger printing : History of finger printing Sir Francis Galton introduced fingerprints as a form of identification. ‘icnofalagometrico' an early fingerprinting filing system Fingerprints follow 3 fundamental principles : Fingerprints follow 3 fundamental principles A fingerprint is an individual characteristic; no two people have been found with the exact same fingerprint pattern. A fingerprint pattern will remain unchanged for the life of an individual;. Fingerprints have general characteristic ridge patterns that allow them to be systematically identified. Revealing of latent finger prints : Revealing of latent finger prints Prints may be collected by revealing them with a dusting of black powder and then lifted with a piece of clear tape. Slide 31: Some investigators use fluorescent powder and UV lights to help them find latent prints on multi-colored or dark surfaces. Magnetic powder can also be used to reveal latent prints. This type of powder works better on shiny surfaces or plastic baggies or containers. Slide 32: The cyanoacrylate fuming method (often called the super glue method) is a procedure that is used to develop latent fingerprints on a variety of objects. Patterns of finger prints : Patterns of finger prints Loop type pattern : Loop type pattern Whorl type pattern : Whorl type pattern Whorl type pattern : Whorl type pattern Whorl type pattern : Whorl type pattern DNA profiling : DNA profiling It is a method of identifying an individual by unique characteristics of that person’s DNA Historical background : Historical background DNA fingerprinting was developed in 1984 by Alec. J. Jeffrey at the University of Leicester He was studying the gene of myoglobin. Steps of DNA profiling : Steps of DNA profiling RFLP (restriction fragments length polymerase) 1st step: cells are broken down to release DNA 2nd step: DNA is cut into pieces by restriction enzymes 3rd step: Place fragments into one end of a bed of agarose gel with electrodes in it. Slide 44: 4. Use an electric current to sort the DNA segments by length. This process is called agarose gel electrophoresis. Electrophoresis refers to the process of moving the negatively-charged molecules through the gel with electricity. Shorter segments move farther away from their original location, while longer ones stay closer. The segments align in parallel rows. Other techniques of DNA profiling : Other techniques of DNA profiling variable number of tandem repeats (VNTR's ) PCR analysis ( polymerase chain reaction) STR analysis ( short tandem repeats) Slide 47: Thanks