Hairs may be analyzed for health care purposes and to detect the presence of drugs, acquire evidence of a crime, or help determine someone’s identity. Such tests can be useful because hair contains accumulations of minerals, including calcium and iron, and various chemicals that have been absorbed or ingested into the body. Hair is one of the places in which the body excretes waste products. Health care professionals can analyze hair to determine the levels of certain nutrients in the body. They can also perform tests to find out if someone has been exposed to certain toxins and/or heavy metals, including aluminum, lead, mercury, arsenic, and cadmium. For this purpose, they use hairs that have not been treated with colorants or other chemicals.

Hair may also be tested to determine whether an individual has used drugs of abuse such as amphetamines, cocaine, marijuana, and opiates. This procedure is conducted by law enforcement agencies in criminal investigations and may also be used to test employees in the military and other workplaces. The use of these test results in court cases is controversial.

Hair is a common form of physical evidence, since it is easily transferred from person to person or from person to place. Hairs are typically gathered as evidence when they can be found at a crime scene or on the body of a victim examined during an autopsy. Some hairs are visible, while others, too small to be seen with the human eye, are collected with special equipment, such as a trace evidence filter. Hairs may show that a victim or perpetrator was at a certain place the crime scene or another location or that they handled objects found at the scene.

Investigators study evidentiary hairs to narrow down a list of suspects. They measure the length of the hair and observe its other characteristics. Using a light microscope, they examine the layers of the hair shaft the outer cuticle, cortex, and inner medulla. The color and texture of the hairs may help them to identify the ethnic group of the perpetrator. They can also identify whether his or her hair color is natural or dyed. Law enforcement officials have developed a method called the “level system of hair color” to label the hair of suspected criminals. This 1-10 scale measures the darkness of hair. Lower numbers signify darker hair. Level 1 is black, moving into lighter shades as the numbers increase, with level 10 being light blond.

Further, lab tests can determine whether it is human hair, animal hair, or from a wig made of synthetic fibers. The shape of the cross section of the hair is typically different for Caucasians or African Americans, so this may indicate the hair’s owner ethnic group. Although this type of hair analysis can aid investigators, such tests cannot prove a person’s identity, since the hairs on any given individual’s head can vary.

DNA testing of the sequence of genetic material found in the hair, on the other hand, can help to establish a person’s identity. In one famous case, historians had long wondered whether young Prince Louis Charles, heir to the French throne, died during the French Revolution. After his parents. King Louis XVI and Queen Marie Antoinette, were executed in 1793, the ten year old prince was kept in a well-guarded prison, where he reportedly died of tuberculosis in 1795. During the 1800s, at least forty three men claimed to be the prince, and some of them were so convincing that people continued to wonder whether or not the boy prince truly had died.

In 1999, scientists extracted DNA from the body of the boy who had died in the prison in 1795. They compared it with DNA samples taken from living and dead members of the French royal family. These samples came from a lock of Marie Antoinette’s hair and hairs from two of her sisters, which had been saved in lockets. More DNA was obtained from tissue samples donated by contemporary descendants of the Hapsburgs, the noble family of Austrian-born Marie Antoinette. These tests confirmed that the deceased child was indeed related to Marie Antoinette.

Hair analysis also has been used in attempts to determine the exact cause of death for Emperor Napoleon 1 of France (1769-1821). His attending physician had noted that Napoleon had a stomach ulcer that became cancerous. His valet had kept a diary, wherein he described Napoleon’s declining health during the months before his death. Based on this account and other findings, a Swedish dentist and amateur toxicologist named Sten Forshufvud published a paper in 1961 suggesting that Napoleon died from arsenic poisoning. An enemy could have given Napoleon small doses of arsenic over a period of time, creating a toxic accumulation. To back up his hypothesis, Forshufvud asked scientists at the Glasgow University Forensic Laboratory to test hair that reportedly belonged to Napoleon. During the early 1960s, a method called neutron activated analysis devised by Dr. Hamilton Smith was the most advanced test available for detecting trace elements in hair. The neutron activated analysis showed that the hair sample from Napoleon contained abnormally high levels of arsenic.

Yet, the controversy continued. Some skeptics said that the hair might not actually have belonged to Napoleon. Even if it was his hair, it could not be proven exactly when the hair had been removed from his head. During Napoleon’s lifetime, members of his household staff had saved locks of his hair, and their descendants sold the hair to collectors. Scientists eventually obtained more hair samples and used newer technology to first confirm that it belonged to Napoleon and then to measure the arsenic levels. Studies done in 2001 showed that the hair contained levels of arsenic seven to thirty-eight times greater than normal.

Still, was Napoleon deliberately poisoned? When scientists conducted further studies on hair samples taken from Napoleon in 1805, 1814, and 1821, they found similar levels of arsenic through the years. These studies suggested that Napoleon was not assassinated by deliberate arsenic poisoning. He may have been exposed to arsenic in his hair tonics or in medications that once were commonly used to treat syphilis. Another possibility was that the arsenic came from wallpaper in the house where Napoleon lived from 1815 to 1821 while he was exiled on the island of St. Helena. Arsenic was a common ingredient in green pigment, and the wallpaper included prominent green designs. Since humans can absorb arsenic through the air, the arsenic in the wallpaper might have affected people living in the house, especially if the wallpaper became moldy. A few other people living with Napoleon had died of unknown causes, and the residents of the house complained of “bad air.” In addition to hair tonic, wallpaper, or medical treatments, the arsenic in Napoleon’s body may also have come from glue or rat poison used in the household. Scholars and historians continue to debate the actual cause of Napoleon’s death. Video How to Style Short Hair

Fuente: guidewhois.com