Blood Components and Functions

Forensic Science

• It is the application of the scientific method to legal questions
• In the criminal justice system, it is the establishment of guilt or innocence of a suspect accused of a crime, across all levels of enforcement agencies and courts.

Forensic Chemistry

• A subdiscipline of forensic science, utilizing established principles to guide analyses in modern forensic laboratories.
• Roots are in medicolegal investigation, toxicology, and microscopy

Famous Forensic Scientists

• James Marsh: British chemist who, in the 1830's, developed a method for testing the presence of arsenic in human tissue; this was the first use of toxicology in a jury trial.
• Dr. Alexander Gettler: An American toxicologist who significantly advanced forensic science through his several publications, including a paper published with his student J. Ogden Baine in 1938 called "The Toxicology of Cyanide," and was instrumental in advancing Forensic chemistry as chief chemist at the New York Medical Examiner's office.

Criminalistics

• A branch of forensic science focused on evaluating physical evidence collected at crime scenes.
• Criminalists conduct crime scene investigations, perform laboratory analyses, write reports, and provide expert testimony.

Physical Evidence

• Any type of physical material found at a crime scene.
• Encompasses everyday items, household chemicals, fabrics, fibers, hairs, glass, fingerprints, soil, plant material, handwritten or typed documents, checks, polymers, plastics, inks, dyes, serial numbers, tools, and tool marks.
• Also includes narcotics, marijuana, drug paraphernalia, weapons, ammunition, shell casings, flammables, accelerants, explosives, body fluids, tire markings, shoe prints, tracks, bite marks, and fabric impressions.
• Cigarette butts, chewing gum, contact lenses, clothing, rags, plastic bags, sawdust, duct tape, and rope may all be submitted as physical evidence to a forensic lab.
• Specialists identify, photograph, log, collect, tag, and transport evidence from the crime scene.

Characteristics of Physical Evidence

• Class characteristics are shared by all members of a particular group and cannot be attributed a single source, but can eliminate association with a suspect or location.
• Individual characteristics are unique traits used to associate an item to a specific individual, suspect, or crime scene, and can attribute evidence to a common source with extreme certainty.

Forensic Scientist and Chemist Qualities

• A forensic scientist is a scientist.
• A forensic chemist is a chemist that applies their knowledge of chemical methods and procedures to solve forensic problems.
• Forensic chemists must be flexible, resourceful, creative, and persistent,
• Forensic chemists often are unaware of sample origins, materials used, product manufacturers, mixed materials, and environmental conditions.

Tools of the Forensic Chemist

• Qualitative and quantitative methods of physical and chemical property evaluation.

Common Methods and Techniques in Forensic Chemistry

• Electrophoresis: Components separate with agarose or polyacrylamide gel when an electric field is applied, allowing for separation
• Spectrophotometry: It analyzes interactions with electromagnetic radiation for screening, structural determination, and drug quantification
• Chromatography: Separation based on physical properties, including gas chromatography (GC), high-performance liquid chromatography (HPLC), and thin-layer chromatography (TLC)
• Microscopy: Magnifies questioned evidence, especially blood, hair, and fibers, for detailed examinations across evidence types.

Principles of Sampling/Handling Evidences Generally

• Sufficient sample quantity should be collected since there is no possibility of a return to the crime scene.
• Maintained individuality means each piece have to to be packed separately due to different location pack
• Standards for comparison are needed, and differences between standards and samples are significant for identification.
• Labeling and sealing prevents both mixing and tampering, and preserves value for evidentiary chain of custody.

Stages of Forensic Chemistry Practice

• Collecting or receiving specimen.
• Chemist writes detailed description in the laboratory notebook including the manner it was collected or secured during examination.
• Communication with prosecutor of examination result.

Blood Evidence

• Often found in violent crimes such as murder, rape, robbery, and assault.
• Vital for solving various crimes.

Nature of Blood and Components

• Blood is a crucial bodily fluid circulating throughout the body.
• Serves various functions, including oxygen transport, nutrient supply, waste removal, immunological functions, coagulation, hormone transport, and signaling tissue damage.
• Blood makes approximately 8% of the body's total weight.
• Blood components: plasma, red blood cells, white blood cells and platelets.

Blood Components Makeup

• Plasma in blood: Accounts for 55% of blood, consisting of water, electrolytes, proteins, hormones, and waste products.
• Formed Elements in blood: Cellular components suspended in the plasma, account for 45% of blood, include red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).

Red Blood Cells (Erythrocytes)

• Transport oxygen from the lungs to tissues, also transport carbon dioxide back from the tissues to the lungs.
• Characterized as biconcave discs containing hemoglobin for oxygen binding.

White Blood Cells (Leukocytes)

• Critical role in the immune system, defending the body against infections and invaders.
• Include neutrophils, lymphocytes, monocytes, eosinophils, and basophils.
• Granulocytes have specific granules that bind primary, neutral, or acidic stains and have various functions
• Agranulocytes lack specific granules but contain some azurophilic granules (lysosomes).

Platelets (Thrombocytes)

• Play a vital roles in blood clotting with small fragments with not nucleus

Plasma Proteins

• Albumins maintain osmotic pressure.
• Globulins include antibodies and contribute to immune responses.
• Fibrinogen is essential for clotting.

Blood Typing

• Blood type determined by the antigens present on red blood cells.
• Antigens help differentiate between one's own cells and foreign cells.
• Introduction of blood with different antigens triggers antibody production.
• Blood type groups include A, B, AB, and O, based on presence or absence of A and B antigens.
• A has the A antigen
• B has the B antigen
• AB have both A and B antigens.
• O possesses neither A nor B antigens.
• If blood with unfamiliar antigens enters the system, antibodies may be produced against it.

Blood Test Methods

• Slide Method:
  • Rapid results, sensitive
  • Slide or glass divided into three parts for different drops of blood.
  • Anti-A, Anti-B, and Anti-D reagents are added, and agglutination indicates specific blood types. Tube Test:
  • Sensitive
  • Utilized with the centrifugation of cells, saline, Anti-A and Anti-B Column/Gel Centrifugation:
  • Modern process to standardize agglutination quantification in microtubes with a gel matrix.
  • Testing enhances analysis, with the use of class beads to speed up the agglutination process

Prevention of HIV Transmission

• Do not share needles used by another individual
• Safe sex practice
• Protect others from HIV
• .Prevent perinatal transmission
• Have a limited amount of sex partners , and consistently go in for testing an treatment.

Blood Pattern Analysis

• Bloodstain patterns are analyzed and interpreted to tell the likelihood or sequence of events occuring at a crime scene.
• BPA assists investigator to reconstruct the crime scene, corroborate witness statements, and include or eliminate possible prepatrators.

Principles of Bloodstain Pattern Analysis

• Bloodstain patterns are studied to understand the size, shape, distribution, and location of bloodstains.
• BPA is used to determine events that did and did not occur.
• Can indicate how long the victim was bleeding.

Types of Bloodstains

• Passive Stains: Created by drops, flows, pools, and injuries.
• Transfer Stains: Occur when objects contact existing bloodstains, or are left behind as wipes/swipes from dragging.
• Projected (Impact) Stains: Caused by blood projecting through air, like spatter, splashes, or arterial spurts.

Types of Spatters

• Impact spatter occurs when force is applied to a liquid blood source.
• Projection spatter is caused by arterial spurting, expulsion, or object castoff.
• Gunshot spatter includes forward spatter from exit wounds and back spatter from entrance wounds.
  • Forward spatters are a mist
  • Back spatters are both large and small

Further Blood Spatters

• Cast-off is blood flung from objects.
• Arterial spray pattern will arise from severed arteries and a spray of spurts can indicate movement
  • Expirated spatter occurs when blood from an internal injury mixes and expels the lungs out through the nose, airways, or mouth.
• With a blood shed event bodily injuries will likely lead to the presence of bloodstein evidence, where the amount can change depending on the severity of crime

Sharp vs Blunt injuries

• Sharp injuries cause less blood, and smaller more linear deposits, especially with thin bladed objects like knives
• Blunt - Bigger objects like bats or hammmers leave bigger injuries.

Types of Blood Patterns

• Droplets in the air while blood is impacted will create specific stains based on the angle, distance, impact, and surface it lands on, creating various spokes or elongation based on type.
• Void patterns show an object blocked blood path, which can be used to see where some one once was. They can be cause by any item like scissors

Visual Inspection

• Overlapping sources may complicate bloodstain interpretation, though details can still arise form analysis and DNA may be needed to assist the analysis.

Semen as Evidence

• Semen is a yellow-white and thick produced by the male reproductive system.
• Carry's sperm to fertilize eff

Key Semen characteristics

• Consisting of cells/sperm produced for female/Ova fertilazation
• Most of Semen is seminal fluid
• Prostate Fluid aids the Sperm in survival
• Seminal Vesicle Fluid provides energy for sperm
• Sperm requires Alkaline PH for the vagina egg protection.
• Anti bacterial properties prevent Sperm from any damage

Semen Factors

• Composition can be changed depending on health
• Sperm in the head will contain DNA critical for the fertility of life

Semen vs Sperm

• Semen is more macroscopic with a volume assessment for samples, 1.5 to 6 mm is normal
• Sperm is more cellular for reproduction with head's to help fertalize the eggs.

Semen Analysis

• Stains are near clear can also be washed away which provides various challenges. Swabbing is useful.
• Visual inspection is necessary with quality analysis, especially with volume assessment, and liquification during the process of gel to liquid
• Consistency and color can be checked, should be yellow-white.

Microscopic Examination

• Stereomacroscopy of three-dimensional semen
• Phosphatase Method, marker for analysis of enzymatic color

Biological Tests for Semen

• Precipitation is a test done within laboratory for forensic science. Antigen test are conducted where visible results will show the type of sperm presented

• Adherance is neccesary to examine the importance quality with analysis with the forensic experts.

Hair As Evidence Considerations

• It is class evidence that's left or fallen at a scene
• Usually easily seen that's resilient it decomposes. With traces that also show persons ethnic backround
• Chemical assessment can reveal the intake details, but follicle will more accurately identify the people

Terminal vs Vellus Haris

• Terminal hairs can regulate heat body and are found around the scalp, eyebrows, and eyelashes from birth with puberty
• Vellus hairs can sprout terminal hairs.

Parts of Hair

• Follicle & Shaft
• Papilla provides nutrition
• Bulb surrounds papilla
• Sebaceous condidtition
• Erector to be upright.

Hair Shaft

• Medulla: Located at the center that influence density and thickness
• Cortex middle layer
• Protective scales

Medulla Types

• Continuous: It will have one unbreaking line of color
• Interrupted: Breaking line that occur consistently
• Fragmented: Line is randomly organized
• Solid Pigmented: Area that filling both of cortex
• None: Doesn't offer pigmentation in the medulla

Analyzing Medullaes with Scales

• This will be calculated by diameter the scale as well as the point thinnest for observation Narrow: 0.6, its used measure for monkeys Medium: Can be seen in cows and horse Thick: .0.5 smaller due to size

Hair Samplings

-Location of samples Can be gathered with tweezers with storage in cellophane, separation is neccesary. Adhesive tape is convenient and useful for general areas like clothing and furniture. Sampled with combing or brushing

• Visual Examination: Check type by density and character. Color and length is a consideration. Cleaning help with clarity. Microscopy Analysis on species origin, and can have body origin Hair has structural Integrity Hair has pigmentation

Fiber as Evidence

• Fibers are another type evidence. Visual Analysis, burning and flourescences are used to find the test and examiner.
• Microscopic will provide reliable and clear view of the fibers .
• Fiber has to be handled to where it wont degraded and prevent contamination. Photos help with clarity.
• Packets and seals help prevent harm.

Class Drug Categories by Origin

• Natural products are extrated from caffine products
• Semi synthesis are natural and synthetic
• Syntetic entirely synthetic substances

Class Drug Categories by Effect

• Analgesics help releive with pain
• Opioid help relieve the pains
• Depressents relieve Central Nervous System and reduce anxiety
• Haliucigents alter perspective in reality
• Stimulants are used stimulate wake funtions

Class Drug Categories by Use

• Preadator - Incapacitaes the user, for assault
• Club Drugs Used for Ecstasy and LSDs
• Performance - Improves functions and performance
• Inalants - Helps take effect for substances

5 Points to Drug Evidence

• Powders include products as herion and cocaine
• Plant products need refrigeration storage to not degrade well,
• Pill identifiers help analysis
• Precursor compounds need chemical synthesis
• Items for Ingestion will be presented. Solvents are useful yet destructive.
• Cutting Agents are added substances, and a taste test of these can provide an estimation of chemical similarity.

How Drugs Can Corrupt Samples

• Powder:
  • Color has to the similar to the original substances such as heroin.
  • Plant Matters such is in bio with require storage to reduce rotting.
• Visual Identification:
  • A visual that have identfication through tablets with size and dimension with aid.

Parrafin and Powder Test.

• Parrafin test that detect the presence of gunpowder
• Swab test check it the gun has been last fire, and has specific reagent.

Fingerprinting

• Fingerprint is a low probabilite that doesn't always match for different people;
• Finger has a immense unique characteristic of itself,
• Fingerprinting has a unique universal structure.
• Structure never changes and it has a identifiable structure for a person Layers:
• Epidermis outer
• Termis Middle
• Under tissue, inside skin.
• Dermal patterns make up ridge and surface.
• Non Volatille: Salt, albumin, or oil make the surface very slippery

Finger printing:

• Patent: Is a visible print that can left for foreign substances, such as paint and mud. It doesn't need any technical aid to see.
• Latent is hard to perceive, and requires chemicals to be identified. There usually oils. Porous surface. Good at having celllous from things likes paper.

Technique for developing fingerprinting

• A.. Powder developments Are the simplest for making it easily see. Adhesions of power will make it visible particles with a similar moister will allow it to the adhesion. Uniform shape form and size is important, Addtion the poweder needs be non reactive so the print quality doesn't alter
  • powders is the primary action for checking latent fingerprint as aid Silver nitrate
• will be utilized as a reasort. After spraying or submerging in the metal itself.
• This the only way it ca be checked with sunlight by decomposing the silver chloride into black.
• Used develop old paterns
• Microsil a special type with like that checks for prints. Applying past for the surface

Toxicology Tests for Samples

• Blood and Plasma should be tested for organic fats, and cells. Has to done through centrifuge method
• Urine: Check straw color is related for the check. The urea checks from the urine
• Vitreous: Check eyes in the eyeball, and for concentration ratios preserved in death
• Liver and body will be tested for tissues , like heart.

Forensic toxicology -Alcohol, and Drugs:

• Alcohol- Is one the main factors of intoxication. CNS the central. A fatal liver level is .40 ml the amount
• Drug facilitated sexual assault, comes incapacitating drugs and alcohol.
• Common scenerio check the victim for any testing with GHD.
• Victims have to report at the hospital to follow it.

Forensic toxicology- Death

• post mortem is the investigation. Determine cause, work from coroner/examiners and investigators.
• COD can show the cause nature / accidental/ Suicide/ Hoimeicde or unsure.
• Drug test must be performed first.
• Many reasons cause of death can change
• famous include jaskcson . heach, moroe .

Sports

Testing Athletes and animals. The WADA checks the standards, and accreditation with labs

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Explore the essential components and functions of blood, including clotting, oxygen transport, immune response, and plasma composition. Understand the roles of different blood cells like red blood cells, white blood cells, and platelets, as well as the importance of plasma proteins.