Beta activity

Radioactivity in environmental waters can originate from both natural and artificial sources. The natural or background radioactivity usuaUy amounts to <100 mBq/L. The development of the nuclear power industry as weU as other industrial and medical uses of radioisotopes (qv) necessitates the deterrnination of gross alpha and beta activity of some water samples. These measurements are relatively inexpensive and are useful for screening samples. The gross alpha or beta activity of an acidified sample is deterrnined after an appropriate volume is evaporated to near dryness, transferred to a flat sample-mounting dish, and evaporated to dryness in an oven at 103—105°C. The amount of original sample taken depends on the amount of residue needed to provide measurable alpha or beta activity. 

Major limitations in fission product decontamination will require tests with mixer-settlers. However, we anticipate from the distribution ratio measurements that Tc, Ru, and Pd will limit the overall decontamination from beta activity (other than from lanthanides). ... 

Gendelman HE, Persidsky Y (2005) Infections of the nervous system. Lancet Neurol 4 12-13 Gerard C, Rollins BJ (2001) Chemokines and disease. Nat Immunol 2 108-115 Gitter BD, Cox LM, Rydel RE, May PC (1995) Amyloid beta peptide potentiates cytokine secretion by interleukin-1 beta-activated human astrocytoma cells. Proc Natl Acad Sci USA 92 10738-10741 GiuUan D, Yu J, Li X, Tom D, Li J, Wendt E, Lin SN, Schwarcz R, Noonan C (1996) Study of receptor-mediated neurotoxins released by HIV-1-infected mononuclear phagocytes found in human brain. J Neurosci 16 3139-3153... 

Early measurements of " Th were on seawater samples and Th was co-precipitated from 20-30 L of seawater with iron hydroxide (Bhat et al. 1969). This procedure may not recover all of the " Th in the sample, and an alpha emitting Th isotope (e g., °Th or Th) is added as a yield monitor. Following chemical purification of the Th fraction by ion exchange chromatography, the Th is electrodeposited onto platinum or stainless steel planchets. The planchets are then counted in a low background gas-flow beta detector to measure the beta activity and subsequently with a silicon surface barrier detector to determine the alpha activity of the yield monitor. The " Th activity is thus determined as ... 

Sea lettuce, Ulva lactuca, whole, Connecticut, 1960, gross beta activity May 5402-6253 AW 21... 

Chakravarti, D. and R. Eisler. 1961. Strontium-90 and gross beta activity in the fat and nonfat fractions of the liver of the coconut crab (Birgus latro) collected at Rongelap Atoll during March 1958. Pacific Sci. 15 155-159. 

Unlike the problems associated with measuring alpha and beta activity in water in the field, the properties of gamma radiation allow it to be measured relatively well in water samples in the field. The standard instrumentation used to measure gamma radiation from water samples in the field is a sodium iodide (Nal) scintillator. 

Wang, W., et al.. Activation of the hematopoietic progenitor kinase-1 (HPKl)-dependent, stress-activated c-Jun N-terminal kinase (JNK) pathway by transforming growth factor beta (TGF-beta)-activated kinase (TAKl), a kinase mediator of TGF beta signal transduction. J Biol Chem, 1997,... 

Nicotine gum simiiariy increases aipha and beta activity on the EEG and decreases theta activity (Pickworth et ai. 1986). In contrast, denicotinized cigarettes do not have any EEG effects (Pritchard et ai. 1999). 

Electrophysiological and cognitive effects The effects of kava on brain electrophysiology were investigated in cats (Holm et al. 1991). Kavain produces high-amplitude delta activity, spindlelike formations, and continuous alpha or beta activity in the amygdala. Similar to barbiturates, kavain prolongs synchronized sleep. 

Another receptor, LXR (Liver X receptor), also exists in alpha and beta forms, and acts as a receptor for cholesterol and its degradation products, which accumulate when cholesterol levels are high. LXRs are expressed in the liver and lower digestive tract, where they regulate cholesterol and bile-acid homeostasis. LXR-beta activates reverse cholesterol transport from the periphery to the liver. LXR-alpha, which is found in the liver, promotes catabolism in the liver and drives catabolism of cholesterol to BAs. Its activation in the liver increases... 

Gross alpha and gross beta activity can be determined by various radioactive counters, such as internal proportional, alpha scintillation, and Geiger counters. Radium in water can be measured by co-precipitating with barium sulfate followed by counting alpha particles. Radium-226 can be measured from alpha counting of radon-222. Various methods are well documented (APHA, AWWA, and WEF 1998. Standard Methods for the Examination of Water and Wastewater, 20 ed. Washington DC American Public Health Association). 

The actual discovery was made by Mile. Marguerite Perey at the Curie Institute in Paris. In 1939 she purified an actinium preparation by removing all the known decay products of this element. In her preparation she observed a rapid rise in beta activity which could not be due to any known substance. She was able to show that, while most of the actinium formed radioactinium, an isotope of thorium, by beta emission, 1.2 0.1 per cent of the disintegration of actinium occurred by alpha emission and gave rise to a new element, which she provisionally called actinium K, symbol AcK (35, 36). This decayed rapidly by beta emission to produce AcX, an isotope of radium, which was also formed by alpha emission from radioactinium. Thus AcK, with its short half-life, had been missed previously because its disintegration gave the same product as that from the more plentiful radioactinium. 

Chlorpromazine and clozapine at low doses lead to an increase in slow (delta, theta) waves and a decrease in alpha activity in the pharmaco-EEG of healthy subjects. Findings regarding beta activity are less uniform. Rohloff et ul. (1992) reported on an increase in slow frequency components and a decrease of alpha and beta activity after 4.0 mg of haloperidol. Low doses of amisulpride (up to 50 mg) were reported to display an alertness-enhancing effect (Rosenzweig et ul., 2002). 

Benzodiazepine anxiolytics and hypnotics lead to a decrease in alpha and an increase in beta activity in pharmaco-EEG trials. With regard to theta and delta activities, the results of different studies vary. Buspirone at the usual therapeutic doses induces no or only a very weak EEG effect (Greenblatt et al., 1994) and is thus differentiated from the benzodiazepine anxiolytics. 

Clams, 15 species, freshwater, 1960, Tennessee River, near Oak Ridge, Sr, shell Connecticut, 1960, gross beta activity American oyster, Crassostrea virginica, soft parts May August December... 

Beall, M.J. and Pearce, E.J. (2001) Human transforming growth factor-beta activates a receptor serine/threo-nine kinase from the intravascular parasite Schistosoma mansoni. Journal of Biological Chemistry 276, 31613-31619. 

Guideline values recommended Gross alpha activity Gross beta activity... 

Refer to Problems 21.13 and 21.11. Calculate the mass of pure l4C needed to provide 17 xCi of beta activity. Note Refer to the procedure followed in Problem 21.14.)... 

The mechanism of beta-activation described above has been substantiated by the observations that 4-hydroxypentanal /S-D-glucopyranoside (3-formyl-l-methylpropyl /3-D-glucopyranoside) (LXXXI)61 as well as the 18-D-glucopyranosides of the propyl (LXXXII) and butyl (LXXXIII) analogs of XI62 are stable in alkaline solution. 

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