forensics plastics, hairs, mass spec, fingerprints

Anagen

Growth Phase

-2-7 yrs

-cells divide rapidly(10 cm/year)

Catagen

(<1%)–Transitional Phase

~10 days

-follicle shrinks to 1/6 size, detaches from dermal papillae, Epithelial root sheath cells die.

-Growth stops, outer root sheath shrinks and attaches to root of the hair (formation of a club hair)

Telogen

10% - Resting(dying) Phase

3-4 weeks

Shaft breaks, hair replaced 

Exogen

2-5 mo

new hair phase/part of telogen, old hair sheds, new hair continues to grow, normal hair shedding.

A new hair is formed and pushes the club hair up the follicle and eventually out. 

PETE

Water bottles, soft drink bottles, food packaging, carpet, rope, cleaning sponge, fabric (polyester), PB jars, tennis balls, yarn, hand soap, cooking oil,, fiberfill, scouring pads, mylar, cassette tapes

HDPE

bottles (milk, shampoo, soap, detergent, bleach, motor oil), cereal liners, furniture, 3D printing, marine products outdoor signs, toys, aspirin, flower pots, signs, trash cans, toys, lumber,  pippin for water & swerve, snowboards, boats, folding chair. 

PVC

construction (pipes), tubing for beverage systems, blister packaging for gum, seals on metal lids, food foils, outdated cling wraps,  tiles, credit cards, blood bags, shower curtains, plastic tablecloths rain coats, film stuff, water bottle, window, door, not good for food, wiring, vinyl records, phonographs

LDPE

food containers (specifically bags), plastic bags, modern cling wrap, wire insulation, orthotics, prosthetics, dispensing bottles, tubing, computer components, diapers, disk drives, swim noodles, dry cleaning bags, fuse beads

PP

Reusable food containers, car batteries, rope, plastic wrap, yogurt tubs, pill containers, disposable syringes, bottle caps, straws, living hinges, plastic tote bags, luggage, carpeting, butter tubs, automobile batteries, rope, lab equipment, packing tape, chip bag

PS

Packing peanuts, styrofoam, tableware, toys, lighting, signs, insulation, appliances, car parts, plastic cutlery, CD case, petri dish

TYPES:

Rigid PS: transparent, rigid, brittle, used in disposable cutlery

Expanded PS: insulator, made from beads of polymer and expanded using steam and pentane

Extruded PS: insulator, made from crystals, resulting in a less water-permeable and stronger insulating final product

PC

shatterproof glass, eyeglass lenses, greenhouses, CDs, UV protection, riot shields, medical devices, exterior lighting feature, electrical telecomm hardware

PMMA

Plexiglass, glass substitute, dentures, bone implants, aquariums, LED lights, windshields, dental fillings, transparent, car windows, smart phone screens and windows, acrylic glass, outdated-contacts

1) Ionization

Ionizer vaporizes then bombards sample with high speed electrons; absorbs energy & loses electrons forming ions, so are drawn to analyzer.

2)acceleration

positive ions from ionization accelerate towards negative plates at a speed dependent on their mass.

3) Deflection

Analyzer consists of electric or magnetic fields, or both. Fields exert electric and/or magnetic forces on charged particles, deflecting them towards detector

(4) Detection

detector records presence of charged particles.

Amount of deflection inversely prop to mass, so lighter particles deflected more.

Also picks up on # of particles of each mass recorded, calculates its % rel abundance.

Ionization Source

substance vaporized then bombarded with high speed electrons; absorbs energy and loses electrons forming ions

Mass Analyzer

separate ions based on charge(based on charge, mass)

Ion Detection System

m/z ratio & abundance information is recorded in a chart.

Iodine fuming

(paper, cardboard, unpainted surfaces) in a vapor tent, heat solid iodine,combines w/carbs in latent print,sublimation, brownish (fades quick) must be photographed or sprayed w/ starch solution, usually nonporous

Ninhydrin

object dipped or sprayed, 24 hrs

reacts w/ amino acids in sweat, turns Ruhemann's purple (discovered by Siegfried Ruhemann)

(yellow if proline, brown if asparagine)

most common on porous surfaces

Cyanoacrylate (Superglue) Fuming:

heat sample in vapor tent, react w/ amino acids & air—ester attaches proteins to fats. forms white sticky material along ridges

nonporous surfaces, household items: plastic, metal, glass, skin

Silver Nitrate

object dipped or sprayed, Cl from salt in perspiration combines w/silver nitrate to form AgCl (+ NO3-), b

lack or reddish brown white print under UV light

Unstable under light, 2 AgCl→ 2 Ag + Cl2

porous surfaces (wood, styrofoam)

Small Particle Reagent (SPR)

wet surfaces, reacts w/ lipids
reaction between the fatty-acid residuals present in the traces and hydrophobic tails of the specific reagents

Wetwop

apply pre-mixed gloop to adhesive side of tape w/camel hair brush, rinse, lifts prints on adhesive surfaces (i.e. tape)