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By: nyarlathotep (41 month(s) ago)

This PowerPoint would be great for my Forensic Science class! Would it be possible for me to download it (giving you full credit, of course)?

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The Wonderful World of Hairs and Fibers: 

The Wonderful World of Hairs and Fibers

Different Scopes used to analyze hair and fiber: 

Different Scopes used to analyze hair and fiber Compound light Comparison Dissecting Polarized Scanning Electron Microscope (SEM)

Stages of Hair “Life”: 

Stages of Hair “Life” Anagen Growing stage Up to 6 years possible Root shaped like “flame” Hair grows ~1cm/month (1” every 10 weeks)

Stages of Hair “Life”: 

Catagen ~3 weeks long Dormant, resting stage Root gets longer and thinner Stages of Hair “Life”

Stages of Hair “Life”: 

Telogen ~6 months Root  Club shaped Pushes out and is shed Lose approximately 70 hairs/day Stages of Hair “Life”

Human Hair Parts: 

Human Hair Parts 1. Root 2. Follicle 3. Shaft 4. Tip 1 2 3 4

Human Hair Parts: 

Human Hair Parts 1. Distal (tip) 2. Proximal (root end) 3. Medulla 4. Cuticle (contains scale pattern) 5. Cortex 1 2 3 4 5

Scale patterns: 

Scale patterns Imbricated Mosaic Petal Pectinate Chevron

Medulla Types: 

Medulla Types Continuous Fragmented Intermittent/interrupted

Medullary Index of Hair: 

Medullary Index of Hair To find the MI Diameter of medulla/hair shaft diameter Humans = <1/3 Other animals = >1/2 Classify Medulla as: Continuous, Interrupted, Fragmented, or Absent

Example Medulla Patterns that can be seen: 

Example Medulla Patterns that can be seen Lattice Vacuolated Uniserial Multiserial

Deer, Dog & Muskrat hair: 

Deer, Dog & Muskrat hair Muskrat Deer

Which is Caucasian, Negroid, Mongoloid Head Hair?: 

Which is Caucasian, Negroid, Mongoloid Head Hair? Caucasian, Europeans, Mexicans, Middle Easterners: oval to round Negroid, Africans oval to flat Mongoloid, Orientals, American Indians: round

Pulled Hair v. Shed Hair: 

Pulled Hair v. Shed Hair Telogen stage Anagen Stage Pulled Hair

Razor, Cut hair & Split hair: 

Razor, Cut hair & Split hair Razor Cut Split

Human eyebrow: 

Human eyebrow

Burned hair: 

Burned hair

Buckling of hair seen in pubic hair: 

Buckling of hair seen in pubic hair

Hair match: 

Hair match This is the view that a comparison scope can give when comparing two matching hairs

The small things in life: 

The small things in life Eyelash mites Bedbug feeding on flesh

Fibers: 

Fibers

Types of fibers: 

Types of fibers Natural fibers Animal fibers are most common at crime scene Man-made

Natural fibers: 

Natural fibers Animal: Wool from sheep most common Goats, camel, alpaca, rabbit, mink, llamas, beaver Plant: Cotton most common Flax (linen), ramie, sisal, jute, hemp Excrement: Silk from silkworm (cellulose from mulberry leaves) Mineral: Asbestos

Cotton fibers cross-section: 

Cotton fibers cross-section

Wool fibers v. Cotton fibers: 

Wool fibers v. Cotton fibers Wool Cotton

Flax Fibers: 

Flax Fibers

Hemp fibers: 

Hemp fibers

Silk fibers: 

Silk fibers Raw thrown Wild silk

Asbestos fibers: 

Asbestos fibers

Man-Made fibers: 

Man-Made fibers Regenerated fibers Machine made from natural materials like cotton or wood 1910 rayon, then acetate, then triacetate Synthetic fibers Most fibers are made synthetically from chemicals 1939 nylon, then polyester and acrylic Shape or cross-section can determine value of the fiber; manufacturer specific

Nylon fiber cross sections: 

Nylon fiber cross sections

Acetate Fibers: 

Acetate Fibers

Nylon fibers: 

Nylon fibers

Orlon Fibers: 

Orlon Fibers

Polypropylene fibers: 

Polypropylene fibers