Protective factors

Sun protective factor Sunroof laminates Sunscreen agents Sunscreen products Sunscreens... 

In vitro absorption-spectrophotometry techniques are available to assess a sunscreen s efficacy, but the preferred methods are in vivo procedures in which a small body site is irradiated with the desired wavelengths for different periods in the presence or absence of a uv protectant. Procedures vary from country to country to determine the incremental timing of the exposure that ultimately allows quantification via sun protective factor (SPE). In the United States, sunscreen preparations are considered OTC dmg products, and the SPE must be specified (54). Even in countries that do not identify these products as dmgs, SPE labeling has become customary. 

Class B—Non-IDLH based on oxygen level between 19.5 and 21 percent, but classified as dangerous due to the airborne presence of toxic or poisonous substance Below IDLH level, but greater than the protection factor offered by air-purifying respirators. 

Breast Cancer. Many studies have observed low incidences of hormone-dependent cancers, particularly breast cancer, in Asian countries compared with Western countries and it is becoming increasingly accepted that dietary factors play an important role. Although breast cancer can occur in either males or females, only about 1 % of all cases occur in men, and male breast cancer is a rare disease in all parts of the world." Although there appear to be some similar risk factors for breast cancer in males and females, there is no indication in the literature that diet is either a risk or a protective factor for male breast cancer. The development of breast cancer is known to be highly dependent on the hormones associated with female reproductive functions, while established genetic factors have been... 

The nominal protection factor (NPE) describes the level of protection afforded by a specific respirator ... 

Table 13.9 Assigned Protection Factors for Respirators and Breathing Apparatus ...

No matter what type of respirator is used, it is of the utmost importance that the revised respiratory standard is adhered to. The revised standard stresses training, documentation, written programs, medical surveillance, fit testing, and a variety of other subjects pertinent to respirators. Of particular interest to the authors is the new approach toward action levels, protection factors, and fit testing. Another important change is OSHAs latest approach on voluntary respirator use. With the new standard in effect, those workers previously considered to be voluntarily wearing respirators should be much better protected. 

Assigned protection factor This was not included in the standard. However, the latest documentation indicates that OSHA will eventually add APFs into the standard. For now, employers should rely on the best available information when selecting the appropriate respirator. 

FIGURE 10.7 Definition of protection factor, pF (This is one definition of contaimnenc efficiency ... 

Different protection factors have been defined. One method is to define it as the ratio of the concentration of a contaminant in the exhaust duct (CJ to the concentration in the breathing zone (C[,) of a person standing in front of the enclosure, for example, a laboratory fume hood ... 

Protection factors based on the ratio of the breathing zone concentration to the concentration inside the enclosure have been defined. Without complete mixing of air inside the enclosure, considerable variations in the concentration are expected. The best evaluation for enclosure concentration without complete mixing is the measurement of the concentration in the exhaust duct. 

Assigned protection factor (APF) The minimum level of respiratory protection that a respirator can be expected to provide, assuming it is properly fitted, worn, and functioning. APFs are assigned by NIOSH. 

Maximum use concentration (MUC) The maximum atmospheric concentration of contaminants in which a respirator cartridge or filter is recommended for use. Can be approximated by multiplying the PEL for the contaminant of concern by the assigned protection factor. 

One fascinating aspect of the effect of the genetic polymorphisms described earlier is that acculturation can partially overcome the protective factor, and Asian groups born in North America may have only partial protection (Goldman 1993 Tu and Israel 1995). In individuals who consume small amounts of alcohol over time, the aversive effects diminish, an effect similar to that described in clinical reports of patients who developed a resistance to the effects of disulfiram. 

The microsomal ethanol oxidizing system is another mechanism of ethanol metabolism. CYP2E1 may be an important enzyme in the metabolism of ethanol in heavy drinkers, who may have a 10-fold increase in activity. Two aUehc variants in the gene cl and c2) are associated with differing enzymatic activity. Approximately 40% of Japanese have the more active c2 allele, which is rare in individuals of European heritage (Sun et al. 2002). It is not believed to be a risk or protective factor in the development of alcohohsm, although current studies are examining its relationship to a variety of ethanol-related diseases. 

Patients with melasma (Eig. 2.3) applied topical sunscreens (sun protection factor 15) and 10% glycolic acid lotion at night for 2 weeks. They were then treated with 50% glycolic acid facial peels once a month for 3 consecutive months. At regular intervals and at the end of the follow-up period (3 months) after the last peel, the degree of improvement in pigmentation was assessed by measuring MASl (Melasma Area and Severity Index) [11]. 

Twice a day moisturizing creams and UVB-UVA sunscreen (with a sun protection factor [SPF] of at least 15)... 

Plasmid- or transposon-encoded ribosomal protection factors are a second mechanism of resistance to the tetracyclines. These proteins are believed to alter the tetracycline binding site on the 308 ribosomal subunit, lowering the affinity for the drugs. 

The general recommendations on energy and fat intake are similar to those for the avoidance of heart disease. However, the recommendation to consume a variety of fruits and vegetables is based partly on the putative presence of diverse protective factors in plant foods. This concept does provide, at least in principle, a rationale for the functional health benefits of plant foods beyond the simple provision of nutrients at a level that prevents symptoms of deficiency. 

The discovery that, in industrialised societies, diets deficient in fruits and vegetables can effectively double the risk of developing many different types of cancer has focused renewed attention on the beneficial properties of these foods (Block e/a/., 1992 Patterson ef a/., 1990 Southon and Faulks, 2002). As we have seen, plant foods are rich in micronutrients, but they also contain an immense variety of biologically active secondary metabolites providing colour, flavour and natural toxicity to pests and sometimes humans (Johnson et ah, 1994). The chemistry and classification of such substances is still a matter for much research and debate, but this has not prevented attempts to isolate and exploit substances that have variously been termed protective factors , phytoprotectants , phytochemicals and nutraceuticals . Phytochemical compounds include ... 

HEANEY R K and FENWICK G R (1995) Natural toxins and protective factors in brassica species, including rapeseed , Nat Toxins, 3, I i i-l. 

Use of sunscreen daily that is applied to all sun-exposed skin. Use of sunscreen with sun protection factor (SPF) 30 or... 

---