Zinedine Zidane

HAIR COLOR CHEMISTRY

People have been coloring their hair for thousands of years using plants and minerals. Some of these natural agents contain pigments (e.g., henna, black walnut shells commonly called “Rittha”) and others contain natural bleaching agents or cause reactions that change the color of hair (e.g., vinegar). Natural pigments generally work by coating the hair shaft with color. Some natural colorants last through several shampoos, but they aren't necessarily safer. It's difficult to get consistent results using natural colorants, plus some people are allergic to the ingredients.

Temporary Hair Color: Temporary or semi-permanent hair colors consists of acidic dyes. These acidic dyes gets deposited onto the outside of the hair shaft or may consist of small pigment molecules that can slip inside the hair shaft, using a small amount of peroxide (or none at all). In some cases several colorant molecules enter the hair to form a larger complex inside the hair shaft. Shampooing will eventually dislodge temporary hair color. These products don't contain ammonia, meaning that the hair shaft isn't opened up during processing and the hair's natural color is retained once the product washes out.

Permanent Hair Color: The outer layer of the hair shaft, its cuticle, must be opened before permanent color can be deposited into the hair. Once the cuticle is open, the dye reacts with the inner portion of the hair, the cortex, to deposit or remove the color. Most permanent hair colors use a two-step process which first removes the original color of the hair and then secondly deposits a new color. Ammonia is the alkaline chemical that opens the cuticle and allows the hair color to penetrate the cortex of the hair. It also acts as a catalyst when the permanent hair color comes together with the peroxide. Peroxide is used as the developer or oxidizing agent. The developer removes pre-existing color. Peroxide breaks chemical bonds in hair, releasing sulfur, which accounts for the characteristic odor of hair color. As the melanin is decolorized, a new permanent color is bonded to the hair cortex. Various types of alcohols and conditioners may also be present in hair color. The conditioners close the cuticle after coloring to seal in and protect the new color.

Hair Lightening: Bleach is used to lighten hair. The bleach reacts with the melanin in hair, removing the color in an irreversible chemical reaction. The bleach oxidizes the melanin molecule. The melanin is still present, but the oxidized molecule is colorless. However, bleached hair tends to have a pale yellow tint. The yellow color is the natural color of keratin, the structural protein in hair, so some gold or red residual color may remain after lightening. Hydrogen peroxide is one of the most common lightening agents. The peroxide is used in an alkaline solution, which opens the hair shaft to allow the peroxide to react with the melanin.

BIOCHEMISTRY of LOVE

Donatella Marazziti, a psychiatrist at the University of Pisa, made a name for herself in 1999 by trying to identify the physiological origins of love. Her original research involved measuring serotonin levels in the blood of people suffering from obsessive compulsive disorder. Then, perhaps thinking "people in love are kind of obsessive," she expanded her study.

Her team recruited students who had recently fallen in love, and who had obsessed about their new love for at least four hours every day but who had not yet consumated the relationship with sex. Seventeen women and three men volunteered. A separate group of people with OCD was studied at the same time, as was a control group.

Members of all three groups were tested for a serotonin transporter protein in their blood platelets. The control group was normal. The obsessive-compulsives were low by 40%. And the people in love, also low by 40%.

Blood serotonin is not a perfect proxy for serotonin levels in the brain, but it's an intriguing suggestion that, biochemically at least, falling in love provokes madness.

Marazziti won an Ig Nobel Prize for this work in 2000. You can find her study written up in Psychological Medicine (vol 29, p 741, 1999). Her abstract follows as:

"The evolutionary consequences of love are so important that there must be some long-established biological process regulating it. Recent findings suggest that the serotonin (5-HT) transporter might be linked to both neuroticism and sexual behaviour as well as to obsessive-compulsive disorder (OCD). The similarities between an overvalued idea, such as that typical of subjects in the early phase of a love relationship, and obsession, prompted us to explore the possibility that the two conditions might share alterations at the level of the 5-HT transporter. METHODS: Twenty subjects who had recently (within the previous 6 months) fallen in love, 20 unmedicated OCD patients and 20 normal controls, were included in the study. The 5-HT transporter was evaluated with the specific binding of 3H-paroxetine (3H-Par) to platelet membranes. RESULTS: The results showed that the density of 3H-Par binding sites was significantly lower in subjects who had recently fallen in love and in OCD patients than in controls. DISCUSSION: The main finding of the present study is that subjects who were in the early romantic phase of a love relationship were not different from OCD patients in terms of the density of the platelet 5-HT transporter, which proved to be significantly lower than in the normal controls. This would suggest common neurochemical changes involving the 5-HT system, linked to psychological dimensions shared by the two conditions, perhaps at an ideational level."

David Beckham "England's BEST"

the ultimate pride

"We are on top at the moment but not because of the club's financial power. We are in contention for a lot of trophies because of my hard work."