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Forensic Serology
Forensic serology is the detection, identification, classification, and study of various bodily fluids such as blood, semen, saliva, and urine, and their relationship to a crime scene. A forensic serologist may also be involved in DNA Analysis, DNA analysis and bloodstain pattern analysis. Serology testing begins with Presumptive and confirmatory tests, presumptive tests which gives the analyst an indication that a specific bodily fluid may be present, but cannot completely confirm its presence. Following the presumptive tests, Presumptive and confirmatory tests, confirmatory tests are done on the same sample to confirm what the unknown substance actually is. Blood detection Blood is composed of liquid plasma and serum with solid components consisting of red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes). To detect blood at a crime scene or in the laboratory, an array of tests can be used. The most publicized test by crime shows is the Lumin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blood
Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood is composed of blood cells suspended in blood plasma. Plasma, which constitutes 55% of blood fluid, is mostly water (92% by volume), and contains proteins, glucose, mineral ions, and hormones. The blood cells are mainly red blood cells (erythrocytes), white blood cells (leukocytes), and (in mammals) platelets (thrombocytes). The most abundant cells are red blood cells. These contain hemoglobin, which facilitates oxygen transport by reversibly binding to it, increasing its solubility. Jawed vertebrates have an adaptive immune system, based largely on white blood cells. White blood cells help to resist infections and parasites. Platelets are important in the clotting of blood. Blood is circulated around the body through blood vessels by the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Polymerase Chain Reaction
The polymerase chain reaction (PCR) is a method widely used to make millions to billions of copies of a specific DNA sample rapidly, allowing scientists to amplify a very small sample of DNA (or a part of it) sufficiently to enable detailed study. PCR was invented in 1983 by American biochemist Kary Mullis at Cetus Corporation. Mullis and biochemist Michael Smith (chemist), Michael Smith, who had developed other essential ways of manipulating DNA, were jointly awarded the Nobel Prize in Chemistry in 1993. PCR is fundamental to many of the procedures used in genetic testing and research, including analysis of Ancient DNA, ancient samples of DNA and identification of infectious agents. Using PCR, copies of very small amounts of DNA sequences are exponentially amplified in a series of cycles of temperature changes. PCR is now a common and often indispensable technique used in medical laboratory research for a broad variety of applications including biomedical research and forensic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RSID (forensic)
Rapid Stain Identification Series (RSID) is designed for fast, easy and reliable detection of human fluids from a variety of samples encountered by forensic laboratories. It has been developed in the United States for the Federal Bureau of Investigation. This group of tests relies on antibody conjugation reactions to form colored complexes in the presence of specific biological fluids. Most tests are also designed so that only specific human fluids will end in a positive result. To perform a test, the sample in question is mixed with a buffer specific to the RSID test. The sample is then deposited onto the sample window where it is pulled through the test and control regions by a paper wick via passive diffusion. The RSID unit is impregnated with fluid-specific antibodies conjugated to colored complexes that will re-dissolve and diffuse at this time. If the fluid in question is present in the questioned sample, antibodies at the test line will react to the colored antibody complexe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CDNA
In genetics, complementary DNA (cDNA) is DNA that was reverse transcribed (via reverse transcriptase) from an RNA (e.g., messenger RNA or microRNA). cDNA exists in both single-stranded and double-stranded forms and in both natural and engineered forms. In engineered forms, it often is a copy (replicate) of the naturally occurring DNA from any particular organism's natural genome; the organism's own mRNA was naturally transcribed from its DNA, and the cDNA is reverse transcribed from the mRNA, yielding a duplicate of the original DNA. Engineered cDNA is often used to express a specific protein in a cell that does not normally express that protein (i.e., heterologous expression), or to sequence or quantify mRNA molecules using DNA based methods (qPCR, RNA-seq). cDNA that codes for a specific protein can be transferred to a recipient cell for expression as part of recombinant DNA, often bacterial or yeast expression systems. cDNA is also generated to analyze transcriptomic pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
DNA Profiling
DNA profiling (also called DNA fingerprinting and genetic fingerprinting) is the process of determining an individual's deoxyribonucleic acid (DNA) characteristics. DNA analysis intended to identify a species, rather than an individual, is called DNA barcoding. DNA profiling is a forensic technique in criminal investigations, comparing criminal suspects' profiles to DNA evidence so as to assess the likelihood of their involvement in the crime. It is also used in paternity testing, to establish immigration eligibility, and in genealogical and medical research. DNA profiling has also been used in the study of animal and plant populations in the fields of zoology, botany, and agriculture. Background Starting in the mid 1970s, scientific advances allowed the use of DNA as a material for the identification of an individual. The first patent covering the direct use of DNA variation for forensicsUS5593832A was filed by Jeffrey Glassberg in 1983, based upon work he had done while ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MiRNA
Micro ribonucleic acid (microRNA, miRNA, μRNA) are small, single-stranded, non-coding RNA molecules containing 21–23 nucleotides. Found in plants, animals, and even some viruses, miRNAs are involved in RNA silencing and post-transcriptional regulation of gene expression. miRNAs base-pair to complementary sequences in messenger RNA (mRNA) molecules, then Gene silencing, silence said mRNA molecules by one or more of the following processes: * Cleaving the mRNA strand into two pieces. * Destabilizing the mRNA by shortening its polyadenylation, poly(A) tail. * Reducing translation (biology), translation of the mRNA into proteins. In cells of humans and other animals, miRNAs primarily act by destabilizing the mRNA. miRNAs resemble the small interfering RNA, small interfering RNAs (siRNAs) of the RNA interference, RNA interference (RNAi) pathway, except miRNAs derive from regions of RNA transcripts that fold back on themselves to form short stem-loops (hairpins), whereas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
RSID
Rapid Stain Identification Series (RSID) is designed for fast, easy and reliable detection of human fluids from a variety of samples encountered by forensic laboratories. It has been developed in the United States for the Federal Bureau of Investigation. This group of tests relies on antibody conjugation reactions to form colored complexes in the presence of specific biological fluids. Most tests are also designed so that only specific human fluids will end in a positive result. To perform a test, the sample in question is mixed with a buffer specific to the RSID test. The sample is then deposited onto the sample window where it is pulled through the test and control regions by a paper wick via passive diffusion. The RSID unit is impregnated with fluid-specific antibodies conjugated to colored complexes that will re-dissolve and diffuse at this time. If the fluid in question is present in the questioned sample, antibodies at the test line will react to the colored antibody complexe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heat-fixed
In the fields of histology, pathology, and cell biology, fixation is the preservation of biological tissues from decay due to autolysis or putrefaction. It terminates any ongoing biochemical reactions and may also increase the treated tissues' mechanical strength or stability. Tissue fixation is a critical step in the preparation of histological sections, its broad objective being to preserve cells and tissue components and to do this in such a way as to allow for the preparation of thin, stained sections. This allows the investigation of the tissues' structure, which is determined by the shapes and sizes of such macromolecules (in and around cells) as proteins and nucleic acids. Purposes In performing their protective role, fixatives denature proteins by coagulation, by forming additive compounds, or by a combination of coagulation and additive processes. A compound that adds chemically to macromolecules stabilizes structure most effectively if it is able to combine with parts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wet Mount
A microscope slide is a thin flat piece of glass, typically 75 by 26 mm (3 by 1 inches) and about 1 mm thick, used to hold objects for examination under a microscope. Typically the object is mounted (secured) on the slide, and then both are inserted together in the microscope for viewing. This arrangement allows several slide-mounted objects to be quickly inserted and removed from the microscope, labeled, transported, and stored in appropriate slide cases or folders etc. Microscope slides are often used together with a cover slip or cover glass, a smaller and thinner sheet of glass that is placed over the specimen. Slides are held in place on the microscope's stage by slide clips, slide clamps or a cross-table which is used to achieve precise, remote movement of the slide upon the microscope's stage (such as in an automated/computer operated system, or where touching the slide with fingers is inappropriate either due to the risk of contamination or lack of precision ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acid Phosphatase
Acid phosphatase (EC 3.1.3.2, systematic name ''phosphate-monoester phosphohydrolase (acid optimum)'') is an enzyme that frees attached phosphoryl groups from other molecules during digestion. It can be further classified as a phosphoric monoester hydrolases, phosphomonoesterase. It is stored in lysosomes and functions when these fuse with endosomes, which are acidified while they function; therefore, it has an acid pH optimum. This enzyme is present in many animal and plant species. Different forms of acid phosphatase are found in different Organ (anatomy), organs, and their blood plasma, serum levels are used to evaluate the success of the surgical treatment of prostate cancer. In the past, they were also used to diagnose this type of cancer. It is also used as a cytogenetic marker to distinguish the two different lineages of acute lymphoblastic leukemia (ALL) : B-ALL (a leukemia of B lymphocytes) is acid-phosphatase negative, T-ALL (originating instead from T Lymphocytes) is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sexual Arousal
Sexual arousal (also known as sexual excitement) describes the Physiology, physiological and psychological responses in preparation for sexual intercourse or when exposed to Sexual stimulation, sexual stimuli. A number of physiological responses occur in the body and mind as preparation for sexual intercourse, and continue during intercourse. #Male physiological response, Male arousal will lead to an erection, and in #Female physiological response, female arousal, the body's response is engorged sexual tissues such as Erection of nipples, nipples, Clitoral erection, clitoris, Vagina#Microanatomy, vaginal walls, and vaginal lubrication. Stimulus (psychology), Mental stimuli and Stimulus (physiology), physical stimuli such as touch, and the internal fluctuation of hormones, can influence sexual arousal. Sexual arousal has several stages and may not lead to any actual sexual activity beyond a mental arousal and the physiological changes that accompany it. Given sufficient sexual st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
