Increasing the service life of shut-off and control fittings in deposits of corrosive and aggressive natural gas

Translated from Fiziko-khimicheskaya Mekhanika Materialov, Vol. 26, No. 5, pp. 122–123, September–October, 1990.     

A model of the posttetanic efficiency of a neuron dendritic spine

A model of postsynaptic processes leading to a prolonged posttetanic modification (potentiation and depression) in the efficacy of the excitatory and inhibitory inputs to the neuron CA3 of the hippocampus was developed. The model enables one to estimate changes in postsynaptic potentials depending on the extent of receptor phosphorylation, which is determined by Ca(2+)-dependent changes in secondary messengers.     

Limitation of activity in an acute model of arthritis: effect of drug treatment

OBJECTIVE AND DESIGN: The limitation of activity and its modification by therapy in an experimental arthritis was studied. SUBJECTS: Female hamsters in groups of six per treatment were used. TREATMENT: An acute arthritis was induced by intraarticular injection of 0.1 microgram lipopolysaccharide (LPS) in hamsters with free access to running wheels. Tenidap at 100 mg%, and piroxicam and indomethacin at 30 mg% were administered in the hamster's normal diet. METHODS: Activity was monitored and analysed by computer. Plasma blood levels of drugs were determined by high pressure liquid chromatographic (HPLC) analysis. RESULTS: Hamsters normally run 10-15 km/day. That distance was reduced to less than 2 km/day after arthritis induction. Speed of movement, essentially the equivalent of walking time, was reduced 40% by the arthritis. However, the time spent in movement (activity time) was more severely affected by arthritic disease. Therapy gave a modest 1.3-fold increase in speed of movement, but a highly significant 2-fold increase in activity time. CONCLUSIONS: The effects of arthritis on activity in this animal model suggest that time spent in movement (activity time) should be considered as an outcome measure in clinical studies. These observations may also help explain why the modest disease improvements obtained with cyclooxygenase inhibition are valued. From a patient perspective, a doubling of activity time is a highly significant improvement in quality-of-life.     

An abrasive material based on silicon nitride for grinding unhardened steels

Conclusions A study was made of the strength of abrasive grains of silicon nitride and of the wear resistance of silicon nitride material under conditions simulating the operation of abrasive grains in a grinding wheel. It is shown that in grain strength the new silicon nitride material is superior to diamond, Kubonit, and El'bor and inferior to Geksanit-A, while in wear resistance in the microcutting of unhardened steel it is comparable with Geksanit-A. On the basis of an electron microscopical examination of the surface structure of a worn microtool a mechanism is proposed for the wear of a material based on silicon nitride in the grinding of unhardened steel. A material based on silicon nitride could be successfully used in abrasive tools for the rough grinding of unhardened ferrous alloys.Translated from Poroshkovaya Metallurgiya, No. 5(173), pp. 34–37, May, 1977.     

Natural killer and lymphokine-activated cytotoxicity following anaesthesia in patients with uveal malignant melanoma

OBJECTIVE: The aim of the study was to determine the pattern of health care utilization of people aged 55-74 years with arthritic pain in the knee or hip. DESIGN: People with current pain were identified in a population-based study. A filter model was used to describe the pattern of health care utilization of people who presented as patients at different levels (GPs or specialist) of the health care system in the Netherlands. SETTING: The study was carried out in the district of Ommoord in Rotterdam in an age- and gender-representative sample of 831 (response 83%; n = 691) people. STUDY PARTICIPANTS: A group of 186 people with current pain was identified. They completed a questionnaire and were interviewed. MAIN OUTCOME MEASURES: Background variables, illness-related variables (including radiological osteoarthritis), and self-reported diagnoses were described and compared for attenders and non-attenders of GPs and specialists. A reference group of patients of GPs was used to determine the validity and generalizability of the findings. RESULTS: Eighty-two per cent consulted a GP (passed filter 1). In 69% of the GP attenders, 'arthritis' was identified (passed filter 2), and 65% of them attended a specialist (passed filter 3). People who did not pass the various filters were different from those who did with respect to the body mass index (lower; OR 1.24), the chronicity of pain (less chronic pain; OR 4.9) and attendance of a physiotherapist (lower; OR 5.6). The chronicity of pain seems of more importance in determining the health care utilization pattern than the severity of pain, the level of disability or the presence of radiological osteoarthritis. We suggest that health promotion interventions could increase the self-management ability of patients and could lower costs.