Oscillatory Behavior of Respiratory Gas Exchange in Resting Man

This study deals with the dynamics of respiratory gas carbon dioxide concentration are three, ten, twenty, and thirty to forty-five minutes and two hours; in oxygen concentration, three, ten, twenty, and thirty minutes and one and four hours; and in respiratory quotient, one, five, ten, and fifteen minutes and two to four hours. exchange in resting man. Spectral analyses are performed on time series representing four-hour continuous records of ventilation, carbon dioxide release, oxygen takeup, end tidal carbon dioxide concentration, end tidal oxygen concentration, and respiratory quotient. Results imply that the temporal behavior of each of these six variables can be characterized by a superposition of a finite set of self-sustained almost periodic oscillations with periods in the range from one minute to four hours and time dependent stochastic variation. In ventilation, carbon dioxide release, and oxygen takeup, individual components have amplitudes of between five and ten percent of mean values and nominal periods of one, four, ten, and twenty minutes and one and two to four hours. Components in oxygen concentration, carbon dioxide concentration, and respiratory quotient have amplitudes of between two and four percent of mean values.     

Hydrometallurgy of precious metals recovery

The hydrometallurgical process for the treatment of gold and silver ores remained unchanged for the first 70 years of this century, and consisted essentially of leaching in cyanide solution followed by solid-liquid separation, with the solid residues being washed as efficiently as possible, and the leach liquor being treated by zinc cementation to recover the precious metals. White this process is generally extremely efficient and fairly cheap, it does have limitations in the treatment of low-grade ores and certain complex ore types. For example, ores with a high content of clay or other soft, fine minerals are usually difficult to filter, and losses of soluble gold or silver in the residues can be unacceptably high. In other situations, where the precious metal host rock contains high concentrations of sulphides such as pyrite or arsenopyrite, for example, or base-metal oxides or carbonates, the traditional process often suffers from poor gold recovery (due to encapsulation of the precious metals in the sulphides) or high cyanide consumption, or both of these. Whereas these occurrences were fairly rare (or were avoided!) in the first half of this century, they are now assuming great importance, and each year a higher percentage of world gold production derives from sources such as these.A number of new hydrometallurgical processes have been developed and implemented in the gold industry in the last 20 years, and these have transformed gold processing into a chemical “high tech” industry, and have allowed increasingly complex ore types and progressively lower grades of ore to be treated economically. As a result, in a period when gold production might have been expected to decline, world-wide production has almost doubled over the two decades.This paper describes the traditional cyanidation and zinc cementation processes, but focuses on the new developments in the industry. In particular, new leaching technologies such as heap leaching for low-grade ores and pressure leaching for refractory sulphide ores are discussed, as well as the carbon-in-pulp and carbon-in-leach processes that have effectively replaced filtration and countercurrent decantation on almost every gold plant built since 1980. Some emerging technologies such as bacterial leaching and resin-in-pulp are also discussed briefly.     

Implications of psychological research on stress and technological accidents.

Psychological research on stress, disasters, and human-made technological accidents have important implications for policy, planning, and legal resolution of situations caused by environmental hazards. The incidence of technological accidents and catastrophes seems to have increased, and the biobehavioral sequelae of such accidents among victims have implications for mental and physical health as well as for intervention and prevention. In this article, research on the long-term effects of human-made disasters is discussed in the context of contributions that psychological research and theory can make in decisions regarding where potential hazards are located, how they are managed, and how accidents are handled. Unique psychophysiological processes associated with toxic accidents make these stressors more potent and likely to cause long-term uncertainty and chronic stress. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of reactivation and size variation in the regulatory region of JC virus in brain tissue

AIMS: To develop a sensitive and specific polymerase chain reaction (PCR) based system for detecting genomic variation in JC virus. To apply this system to formalin fixed, paraffin wax embedded brain tissue from patients with and without progressive multifocal leucoencephalopathy (PML). METHODS: A pair of primers (JC1 and JC2) were designed to be complementary to the early and late regions of JC and BK polyomaviruses, respectively. A third primer (JC3), internal to JC1 and JC2, was designed to be specific for JC virus. The specificity of JC3 was investigated by amplifying plasmids with BK or JC virus genomes. Sensitivity was estimated by titration of a plasmid containing JC virus genome. Seven brains from patients with PML (PMLB) and 30 from patients without PML (non-PMLB) were amplified using JC1 and JC2, followed by JC1 and JC3. Amplification of the beta globin gene was used as an amplification control. RESULTS: Amplification with JC1 and JC2 was common for JC and BK viruses, but with JC1 and JC3 it was specific for JC virus. The sensitivity of the system was 25 copies of JC plasmid per 10 microliters of digested tissue. Five out of seven PMLB and 28 of the 30 non-PMLB amplified for beta globin, but only the PMLB gave a signal with polyoma primers. Hypervariation of the length of the regulatory region of the JC isolates in the PML tissues was consistent with the presence of multiple strains of JC. CONCLUSIONS: Variation in the regulatory region of JC virus can be specifically and sensitively detected from routinely processed, paraffin wax embedded brain tissue. Variation in the regulatory region is common in PML derived JC strains, but JC virus was not detectable in non-PMLB tissue.     

Role of cognitively stimulating home environment in children's academic intrinsic motivation: a longitudinal study

The short- and long-term, and direct and indirect, relations between cognitively stimulating home environment and academic intrinsic motivation were investigated in a longitudinal study from childhood through early adolescence. Structural equations modeling was used to test the hypothesis that home environment positively predicts academic intrinsic motivation over this period. It was also hypothesized that home environmental processes would positively predict motivation controlling for socioeconomic status (SES). When children were age 8, home environment (comprising both direct observations and parent report) and SES were measured. Academic intrinsic motivation was assessed at ages 9, 10, and 13. Results supported the hypotheses. Home environment had statistically positive and significant, direct and indirect paths to academic intrinsic motivation from childhood through early adolescence, indicating both short- and long-term effects across these ages. Moreover, home environment was significant above and beyond SES. The findings revealed that children whose homes had a greater emphasis on learning opportunities and activities were more academically intrinsically motivated.     

Diabetes care for Medicare beneficiaries. Attitudes and behaviors of primary care physicians

OBJECTIVE: To obtain information related to primary care physician (PCP) attitudes, knowledge, and practice patterns, as well as perceptions about barriers to care and the use of materials to assist in the delivery of diabetes care for elderly patients in the office setting. RESEARCH DESIGN AND METHODS: A survey was mailed to a random sample (n = 900) of PCPs (internal medicine, family practice, and general practice physicians and endocrinologists) from the states of Alabama, Iowa, and Maryland who met selection criteria and provided diabetes care to > or = 25 Medicare beneficiaries during calendar year 1993. RESULTS: Respondents provided self-reported information regarding diabetes care for elderly patients. PCP respondents (n = 370) considered blood glucose control to be the most important treatment goal. Most respondents (92%) considered acceptable GHb values to be those < 8%. Blood pressure measurement and foot inspections for the detection of ulcers and infection were the most commonly reported routine procedures performed as part of an office visit. Laboratory tests reported to be frequently ordered included GHb, serum creatinine, and proteinuria tests. Patient nonadherence to the treatment regimen was reported to be the most common barrier to care. The majority of respondents reported using two treatment aids in caring for patients with diabetes. CONCLUSIONS: The results of this study provide some evidence that PCP self-reported attitudes, knowledge, and practice patterns in delivering diabetes care for elderly patients in the office setting more closely reflect current recommended practice than reported in previous physician surveys. Opportunities for improvement still exist.     

Design optimisation of cheap power-augmentation devices for a flexible-sail,horizontal-axis wind-turbine

Previous investigations have shown that the maximum power outputs from small, horizontal-axis wind-turbines can be significantly increased if tip-fins and centre-bodies are added to the turbine. This paper describes quantitatively the effects of employing these two power enhancement devices simultaneously, and presents further optimisation data for tip-fins when used in conjunction with a centre-body augmented rotor.     

The potential role of BAX and BCL-2 expression in diffuse alveolar damage

Apoptosis of type II pneumocytes has been identified in diffuse alveolar damage (DAD), is associated with p53 and WAF1 expression, and may be of pathogenetic importance. BAX, a homologue of BCL-2, is induced by p53 and is a promoter of apoptosis. The proapoptotic effect of BAX is negatively regulated by its binding with BCL-2. In this study, we sought to investigate that role of BAX and BCL-2 in DAD. We hypothesized that alterations in BAX and BCL-2 expression may be important in determining the susceptibility of type II pneumocytes and interstitial cells to apoptosis. Twenty-eight cases of DAD and 16 control cases (i.e., lung tissues adjacent to resected tumors) were retrieved from the files of the University of Utah and the Armed Forces Institute of Pathology. Immunohistochemical stains were performed with antigen retrieval by microwave using antibodies recognizing BAX and BCL-2. The percentage of positively staining pneumocytes and interstitial cells was estimated in each case to the nearest 10%. BAX expression was markedly increased in pneumocytes and interstitial cells in DAD compared with control lung tissues. In DAD, BAX was identified on an average of 80% of alveolar pneumocytes (range 30 to 100%) and 70% of interstitial cells (range 20 to 90%). In control lungs, BAX was identified on an average of 10% of pneumocytes (range 0 to 20%) but not in interstitial cells. Focal BCL-2 staining was identified in interstitial myofibroblasts in 7 of 25 cases of DAD but was only identified in bronchiolar epithelium of control lungs. These results suggest that the induction of BAX in DAD may enhance the susceptibility of alveolar epithelial cells to apoptosis, whereas BCL-2 expression may contribute to the absence of apoptosis in interstitial myofibroblasts. Expression of BCL-2 in interstitial myofibroblasts may contribute to the development of pulmonary fibrosis in some patients.     

Information-seeking and maternal self-definition during the transition to motherhood.

The self-definitional processes accompanying the transition to motherhood were examined in this study. A cross-sectional sample of more than 600 women who were planning to get pregnant within 2 years, pregnant, or in the postpartum stage completed extensive questionnaires pertaining to their experiences of pregnancy and motherhood. On the basis of the assumption of the "self-socialization" perspective that individuals actively construct their identities in response to life transitions, our analyses focused on the role of information-seeking in the developing self-definitions of women becoming mothers. As predicted, (a) women actively sought information in anticipation of a first birth, (b) they used this information to construct identities incorporating motherhood, and (c) after the birth the determinants of their self-definitions shifted from indirect sources of information to direct experiences with child care. Hence, consistent with the self-socialization perspective, information-seeking did play an important role in the women's developing self-conceptions during this life transition. Mechanisms by which information gathered may alter self-conception are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)