Essay on Forensic Serology: Observing, Grouping & Classifying Body Fluids in Crime Scenes

Introduction

Forensic serology is the observation, grouping, or classifying and the study of body fluid like blood, semen, vomit, saliva, breast milk, urine, perspiration, and fecal matters in the crime scene relationship. Forensic serology is very helpful as it helps the forensic scientist in separating fluids of the body that are detected in crime scenes, and multiple tests are done upon them to assist in the identification of their origin. The study helps in finding the owners of the fluids hence being able to get the people involved in the crime scene (James, 1998).

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There are very many cases of sexual assaults that are mostly rape cases around the globe. To be able to find who the sex offenders are, forensic sperm detection has to be done where the examination of the exhibit is done to detect any semen stains. In forensic medical practices, there are several ways that scientists might use to identify the components of the seminal fluids during the process of investigation of the claimed sexual assault (James, 1998).

According to the crime museum during the semen analysis, different lights are used in search of stains in either bedsheets or clothes like the laser. Tests are then done on the found fluids to determine their biological fluid nature. Other options like blood, saliva, or urine are used in cases where there is no blood in the biological fluid (James, 1998). The description of the DNA begins by identifying the stain as seminal fluid. The semen can stay up to seven days in a cloth, and they can be detected even after the fabric has been washed. After identification of the semen, it is tested for sperm, which have more DNA that could help in identifying a suspect to the case. With the detection of sperm, the scientist doing analysis must identify the item that has most sperm so that it can be used to get the DNA because it has high possibilities than others (James, 1998).

A combination of bright field microscopy and general cell staining is used in the identification of sperm. The formula has been used in forensic serology for over forty years. This method, though, is the most popular one, is not seen as the best due to the long duration of time it consumes during the sperm search conducted by analysts (van Oorschot, 2006). The reason that makes this process very common is that the individual sperms found in the exhibit don't have most sub-cells that are required for morphological recognition. There are several ways that forensic scientists use in the identification of seminal fluids. They are visual detection of seminal fluids, acid Phosphatase, Prostate-Specific Antigen (PSA and p30), and Microscope Examination. All of them have their pros and cons that I will discuss below (van Oorschot, 2006).

Visual Detection of Seminal Stains and acid phosphate

The semen of a human being is white, but some can have yellow sperm that is caused because of having more white blood cells than usual from a sexually transmitted disease. The identification of semen is a sexual assault case that is very important as it brings the situation close to justice by the identification of the suspect or suspects. The two most common methods are used in the detection of sperm stains in the crime scenes that are chemical examinations and florescence. For the intrinsic stains to be discovered, an alternative light source is established to convert the light that causes semen to be fluorescent under different wavelengths (van Oorschot, 2006). The second method of chemicals is used to identify the existence of activities of acid phosphate in the semen. According to research done by forensic scientists suggest that apart from the stain concentration, the substrate color also helps in the identification of semen. The limitation of this method is that scientists need to take significant considerations of the background color in the selection of aggravation light wavelength to detect the diluted semen. This limitation makes it not the best way of semen detections though it works in most situations. The acid phosphate is generally the water-soluble that is found in highly concentrated seminal fluid. When the acid phosphate is detected, there is a high chance of semen detection. It is swift to detect semen in high concentrated fluids, which makes it easier for forensics to get the DNA of the suspect. Still, this process might take longer or may not be possible where there is a low concentration of the seminal fluids (van Oorschot, 2006).

Microscope Examination

This method is described as the classical regarding the identification of semen from an exhibit. This process has positive outcomes as the microscopes slides are stained and are then scanned in very high power of magnification to detect the sperms (van Oorschot, 2006). In this process, there is a protocol that is followed by the experts before the experiments are done. The collection of samples, taking them to the lab as they are sealed. The benefit of this process is because the quantity of relative sperm and the empirical cell can be observed. It's beneficial because most DNA is contained in sperm, while most empirical cells that are found in the crime scenes are mostly female (van Oorschot, 2006). The limitation is that without enough care, the samples can be tampered with before evaluation (van Oorschot, 2006).

Prostate-Specific Antigen (PSA and p30)

The produced glycol-protein by the prostate gland and manufactured in the seminal plasma is a proper marker towards the detection of semen in the crime scenes, which also include the suspects who might have undergone vasectomy or individuals with azoospermia. The method states that high concentrations of PSA can cause a negative result of the membrane test (van Oorschot, 2006).

Physical Evidence Gathered in Cases of Rape

The collection of evidence and preservation of it is essential in the judgment of facts. The evidence must be identified, collected, then packed and secured for the examination by the forensic team. The physical evidence that is gathered in the footprints and the footprints that are found on the crime scene or on the exhibit, blood and other fluids of the body like saliva, or semen, the tracks of tires that are on the scene, hair on the stage is also collected and sealed in an envelope, fire debris and even fibers. The area is also photographed for reference to the physical view of the scene (van Oorschot, 2006).

Foundation for Explosives and Their Ramifications of Velocity, Deflagration, and Detonation

Arson and explosion investigation is a process that details the analyzing of discoloring and chemical residues that are found on the debris on crime scenes (Krehl, 2008). The process helps in the determination of whether the event that took place was accidental or intentional, identifying the chemicals that are found on the scene and also reconstructing the happening of the arson or the explosion (Krehl, 2008).

Deflagration is a fast traveling fire through gas at a subsoil speed. The speed of the burning of the explosion is lower than the rate of the surrounding sound. The propagation velocity of the flame is 100 meters per second less while the overpressure is 0.5 bar less (Krehl, 2008). Examples of such are the gunpowder in a firearm, the gas stove that is fueled with natural gases, and fireworks. This type of fire is dependent on fuel, and it burns outwardly. The fire starts only with a spark but later spreads in a circular movement with the availability of fuel. Lack of fuel leads to the stoppage of the fire (Krehl, 2008).

Detonation means to explode in other words. An explosion occurs from a reaction of decomposition or when too much energy is released in a short period. This kind of bombing is very destructive and is considered dramatic (Krehl, 2008). The explosion is distinguished by an accelerated exothermic forepart that exceeds one hundred meters per second to two hundred meters per second and remarkable overpower of up to twenty bars. The shockwave is driven by the forepart ahead. A detonation, therefore, does not need to combine with oxygen though it is an oxidation reaction form (Krehl, 2008). Unstable molecules are the ones that release notable energy after their split and blend again to new configurations. High explosives that are examples of detonation are dynamite, picric acid and, nitroglycerine. The explosion is used in making weapons such as nuclear and chemical bombs (Krehl, 2008). They are very destructive. They can also be used in mining and even road construction.

References

Krehl, P. O. (2008). History of shock waves, explosions, and impact: a historical and biographical reference. Springer Science & Business Media.

Meloan, C. E., & James, R. E. (1998). Lab Manual: Criminalistics: an Introduction to Forensic Science [by] Richard Saferstein. Prentice-Hall.

Vandenberg, N., & van Oorschot, R. A. (2006). The use of Polilight in the detection of seminal fluid, saliva, and bloodstains and comparison with conventional chemicalbased screening tests. Journal of forensic sciences, 51(2), 361-370.