Beta rating

A sample of tritium, H, was observed to produce beta rays at the rate of 1200 per minute. Ten months later the beta rate of the sample was 1144 counts per minute. To what value of the half-life of tritium does this measurement lead ... 

The Beta rating system is simple in concept and can be used to measure and predict the performance of a wide variety of filter cartridges under specified conditions. The rating system is based on measuring the total particle counts at several different particle sizes, in both the influent and effluent streams, a profile of removal efficiency emerges for any given filter. 

Certain factors and product precursors are occasionally added to various fermentation media to iacrease product formation rates, the amount of product formed, or the type of product formed. Examples iaclude the addition of cobalt salts ia the vitamin fermentation, and phenylacetic acid and phenoxyacetic acid for the penicillin G (hen ylpenicillin) and penicillin V (phenoxymethylpenicillin) fermentations, respectively. Biotin is often added to the citric acid fermentation to enhance productivity and the addition of P-ionone vastly iacreases beta-carotene fermentation yields. Also, iaducers play an important role ia some enzyme production fermentations, and specific metaboHc inhibitors often block certain enzymatic steps that result in product accumulation. 

Beta receptors of the beta-1 subtype mediate an increase in heart rate and increased force of contraction they are also found in the central nervous system. E and NE are equaHy potent agonists and selective antagonists are atenolol [29122-68-7] and betaxolol [63659-18-7]. Beta-2 receptors are weH known for their involvement in relaxing bronchioles. E is a more potent agonist than NE procaterol [72332-33-3] is a selective agonist ICl 118551 and a-methylpropranolol are selective antagonists. A particular amine may act on both alpha and beta receptors or predominandy on one type. NE acts mainly on alpha-1, E on both alpha and beta, and isoprotemol [7683-59-2] almost exclusively on beta receptors. Numerous antagonists also differentiate between... 

The beta-conidendrol is incorporated as an antioxidant and is frequently referred to in the patent literature, as is also di-P-naphthyl-p-phenylenediamine for this purpose. It is claimed that in the example given above the degradation rate at 222°C is only 0.09% per minute compared with typical values of 0.6-0.8% for unesterified polymer. 

ANSPIPE Calculates pipe break probability using the Thomas Model BETA Calculates and draws event trees using word processor and other input BNLDATA Failure rate data... 

Some of the side effects due to beta blockers such as the slowing of heart rate can be counteracted by administration of drugs which antagonize the alpha adrenergic receptors. The... 

Cracking, or beta-scission, is a key feature of ionic cracking. Beta-scission is the splitting of the C-C bond two carbons away from the positive-charge carbon atom. Beta-scission is preferred becau.se the energy required to break this bond is lower than that needed to break the adjacent C-C bond, the alpha bond. In addition, short-chain hydrocarbons are less reactive than long-chain hydrocarbons. The rate of... 

Because beta-scission is mono-molecular and cracking is endothermic, the cracking rate is favored by high temperatures and is not equilibrium-limited. 

The volume will decrease when renal impairment is associated with a decrease in the elimination rate beta (betaNorm => betaFail). On the other side, the volume will increase when the free plasma fraction (fp) increases in renal impairment where jp = 1 - PB%. The volume decreases, when the free tissue fraction (ft) increases in renal impairment. 

XXVII) at the 4, 5, and 6 positions respectively (these being all beta to the side chain), initial rates (lO7 ) at 50 °C were 400, 480, and 380, which are each about... 

According to quantum mechanics, an electron has two spin states, represented by the arrows T (up) and l(down) or the Greek letters a (alpha) and P (beta) We can think of an electron as being able to spin counterclockwise at a certain rate... 

MW + 1 ion), and this reaction is 35-40 kcal./mole exothermic. We might expect that the rate for this reaction would be appreciably greater than the rate for primary H abstraction, and we consequently postulate that primary H abstraction to yield MW — 1 ions will not occur to any significant extent. The other process we must consider is a simple extension of Reaction 12—namely, beta fission at a branch point. However, we now wish to consider the case where the branch point is a quaternary carbon. As a typical example ... 

HEATRO = heat of reaction for the polymerization, cal/mole TF = reactor inlet temperature, °C DM0 = reactor fluid density, mole/l BETA = 3-scission reaction rate constant... 

Because the path of the s process is blocked by isotopes that undergo rapid beta decay, it cannot produce neutron-rich isotopes or elements beyond Bi, the heaviest stable element. These elements can be created by the r process, which is believed to occur in cataclysmic stellar explosions such as supemovae. In the r process the neutron flux is so high that the interaction hme between nuclei and neutrons is shorter that the beta decay lifetime of the isotopes of interest. The s process chain stops at the first unstable isotope of an element because there is time for the isotope to decay, forming a new element. In the r process, the reaction rate with neutrons is shorter than beta decay times and very neutron-rich and highly unstable isotopes are created that ultimately beta decay to form stable elements. The paths of the r process are shown in Fig. 2-3. The r process can produce neutron-rich isotopes such as Xe and Xe that cannot be reached in the s process chain (Fig. 2-3). 

Mortensen PB. C6-C10-dicarboxyUc aciduria in starved, fat-fed and diabetic rats receiving decanoic acid or medium-cbain triacylglycerol. An in vivo measure of the rate of beta-oxidation of fatty acids. Biochim BiophysActa, 1981, 664(2), 349-355. 

RfD = reference dose, 0.00005 mg/(kg-day) for alpha-, beta-endosulfan, and endosulfan sulfate FCR = fish consumption rate, set at 0.030 kg/day... 

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