Human body control

T he sea is a living system and, like other living systems, its properties are a complex fimction of many chemical and biological processes. Some of these involve, directly or indirectly, the protonation of basic species, and consequently the state of the seawater system— its equilibrium processes and the rate at which equilibrium is being approached —depends on pH. Interactions within the hydrosphere, in which carbonate, phosphate, and silicate play an important role, regulate the pH within rather narrow limits, as the acid-base balance of the human body controls the pH of human blood. 

The manner in which the human body controls temperature is important not only under normal conditions but also during exercise, fever, and trauma induced by injury, bums, surgery, etc. Over longer periods of time, hormones, adaptation, and acclimatization can exert significant effects. Although the work reported here is limited to normal short-term regulation, it is possible that the other situations can be explained in terms of modifications of the basic mechanism. 

The human body is itself is an automatic thermo-regulated organism. The body constantly generates heat, CO2 and HjO by the metabolism of food and muscle activity. The human body controls the release speed of heat by blood vessel dilatation or constriction, muscle and sweat gland activity, etc., and then regulates the body temperature. 

X-rays find wide applications in X-ray photography and in crystallography. Prolonged exposure of the human body to the rays induces a dangerous form of dermatitis, and even sterility, but controlled exposures are applied to alleviate cancer. 

The value of insecticides in controlling human and animal diseases spread by insects has been dramatic. It has been shown that between 1942 and 1952, the use of DDT in pubHc health measures to control the mosquito vectors of malaria and the human body louse vector of typhus saved five million hves and prevented 100 million illnesses (4). Insecticides have provided the means to control such important human diseases as filariasis transmitted by Culex mosquitoes and onchocerciasis transmitted by Simulium blackflies. 

Nitronaphthalene is metabolized to the carcinogenic 2-naphthylarnine in the human body (39). Respirators, protective clothing, proper engineering controls, and medical monitoring programs for workers involved in making by-product 2-nitronaphthalene should be used. 

Alternatively, fabric patches treated with permethrin have been evaluated against natural and laboratory strains of human body flee in Pern. Permethrin-treated fabric is toxic to flee on contact and quickly affects feeding behavior, even when washed up to 20 times. Thus permethrin-treated clothing intermpts disease transmission, and offers a passive louse control not previously feasible (39). 

Isocyanates. Isocyanates in general are toxic chemicals and require great care in handling. Oral ingestion of substantial quantities of isocyanates can be tolerated by the human body, but acute symptoms may develop from the inhalation of much smaller amounts. The inhalation of isocyanates presents a ha2ard for the people who work with them as weU as the people who Hve in the proximity of an isocyanate plant. Adequate control of exposure is necessary to achieve a safe working environment. The suppHers Material Safety Data Sheets (MSDS) have to be consulted for the most current information on the safe handling of isocyanates. 

To meet the cleanliness need, all elements of the process are controlled to minimize sources of contamination. Air normally contains a large volume of contaminants in the form of dirt, dust, and poUen. The human body sheds a large volume of particulate contaminants such as skin, phlegm, hair, etc. 

Sodium nitrite is produced in the human body by the action of saliva on sodium nitrate, and is important in controlling bacteria in the stomach, to prevent gastroenteritis. The body produces more sodium nitrite than is consumed in food. 

A different approach to polyphosphazene-based drug delivery systems deals with hydrolytically unstable phosphazene substrates, able to degrade in a controlled way under physiological conditions in human body. A list of these bio-erodible substrates is reported in Table 21. 

The Na -selective electrodes based on silicone-rubber membranes modified chemically by (8) and (9), were also investigated for Na assay in control serum and urine [22]. The found values for the Na concentrations in both of the serum and urine samples are in good agreement with their corresponding actual values with a relative standard deviation of about 1%. These results suggest that the Na -selective electrodes based on silicone-rubber membranes modified chemically by calix[4]arene neutral carrier (8) are reliable on assay in human body fluid. 

An application already in the market is the temperature control utilizing PCM for transportation of pharmaceutical goods or other temperature sensitive goods. Also in the market is the utilization of PCM for cooling or heating of the human body, since it has been demonstrated both for personal comfort and for medical therapy. Passive cooling of buildings and of telecom cabinets are examples of widespread applications. 

Physiology is the study of the functions of the human body. In other words, the mechanisms by which the various organs and tissues carry out their specific activities are considered. Emphasis is often placed on the processes that control and regulate these functions. In order for the body to function optimally, conditions within the body, referred to as the internal environment, must be very carefully regulated. Therefore, many important variables, such as body temperature, blood pressure, blood glucose, oxygen and carbon dioxide content of the blood, as well as electrolyte balance, are actively maintained within narrow physiological limits. 

Skeletal muscle comprises the largest group of tissues in the human body and accounts for up to 40% of total body weight. This type of muscle, which is innervated by the somatic nervous system, is under voluntary control. Skeletal muscle performs many important functions in the body, including ... 

Thrombin is a serine protease and is one of the key enzymes in the blood coagulation system. It plays fundamental roles in the human body, but the major interest is in the control of throm-... 

Abstract Human body odour is individually specific and several lines of evidence suggest that to some extent it is under genetic control. There are however numerous other sources of variation, commonly labelled as environmental factors, which are the main aim of this paper. These include 1) reproductive status, 2) emotional state, 3) diet and 4) diseases. We primarily focus on axillary and genital odours as they have been proposed to have communicative function. We prelusively conclude that a specific diet and some diseases have major impact on variations in human body odour. 

HCN is detoxified to thiocyanate (SCN ) by the mitochondrial enzyme rhodanese rhodanese catalyzes the transfer of sulfur from thiosulfate to cyanide to yield thiocyanate, which is relatively nontoxic (Smith 1996). The rate of detoxification of HCN in humans is about 1 pg/kg/min (Schulz 1984) or 4.2 mg/h, which, the author states, is considerably slower than in small rodents. This information resulted from reports of the therapeutic use of sodium nitroprusside to control hypertension. Rhodanese is present in the liver and skeletal muscle of mammalian species as well as in the nasal epithelium. The mitochondria of the nasal and olfactory mucosa of the rat contain nearly seven times as much rhodanese as the liver (Dahl 1989). The enzyme rhodanese is present to a large excess in the human body relative to its substrates (Schulz 1984). This enzyme demonstrates zero-order kinetics, and the limiting factor in the detoxification of HCN is thiosulphate. However, other sulfur-containing substrates, such as cystine and cysteine, can also serve as sulfur donors. Other enzymes, such as 3-mercapto-pyruvate sulfur transferase, can convert... 

Regulatory officials nevertheless act on the basis of such hypothetical risks ( hypothetical definitely does not mean imaginary it means that the risk estimates are based on certain scientific hypotheses and that they have not been empirically tested). Such actions are in part based on legal requirements (Chapter 11) and in part on the prudence that is a traditional feature of public health policies. The scientific information, assumptions, and extrapolation models upon which risk assessments are based are considered sufficiently revealing on the question of human risk to prompt risk-control measures. To put off such actions until it is seen whether the hypothesized risks are real - to wait for a human body count - is considered to be an unacceptable course. 

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