The role of hyperthermia in the water economy of desert birds

A number of authors have suggested that hyperthermia, the elevation of body temperature (Tb) 2 degrees-4 degrees C above normal, contributes to a reduction in total evaporative water loss (TEWL) in birds. Information about the role of hyperthermia in the water economy of birds is scattered throughout the literature. We purposed to collate the available information on this subject, to reevaluate the benefits and costs of this process, and to assess its net effect on the water economy of birds, especially species living in deserts. In this review, we first consider the current model of heat balance in birds at high ambient temperatures (Ta), and show that, in most studies performed at a high Ta, birds were increasing their Tb, a violation of the assumption of steady state conditions. Next, we incorporate the rate of heat gain into calculations of the dry heat transfer coefficient (h), below and above temperature equality (Ta=Tb). We develop a method to calculate h at Ta=Tb, using l'H?pital's rule. The combined result of our approach suggests that birds increase their dry heat transfer even when Ta is above Ta=Tb, contrary to our prediction. Finally, we explore aspects of hyperthermia that reduce water loss, such as an improved thermal gradient and heat storage, and aspects that may augment water loss, the latter a result of increased respiratory water loss when Tb is elevated. Our analysis of the combination of these three factors suggests that, during acute exposure to high Ta (1 h), birds over a size range of 10-1,000 g save about 50% of their TEWL by becoming hyperthermic. For chronic episodes of high Ta (5 h), small birds save water by hyperthermia but large birds do not.     

Controlled synthesis and formation mechanism of sodium yttrium fluoride nanotube arrays

Cubic and hexagonal sodium yttrium fluoride were successfully synthesized from yttrium nitrate, sodium fluoride and poly-ethanediol in propanetriol solvent under a facile hydrothermal route. By regulating the molar ratio of yttrium and fluoride, hydrothermal tem-perature and reaction time, the phase and shape of sodium yttrium fluoride were commendably controlled. The as-prepared products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectrum (EDS) techniques. It was revealed that the hollow-structured Na(Y1.5Na0.5)F6 nanotubes self-assembled and arrayed orientedly to be bamboo raft-shaped. The for-mation of hexagonal Na(Y1.5Na0.5)F6 nanotube arrays was attributed to solid-liquid-solid process and Oswald ripening. This study provided a simple method to prepare hexagonal bamboo raft-shaped Na(Y1.5Na0.5)F6 on a large scale, which broadened their practical applications.     

佛山城区体育消费者心理特征与消费方式研究

简述了佛山城区不同人群体育健身消费者的购买行为心理特征及其消费类型,从消费行为类型的角度指出了不同人群体育消费者的消费方式,使不同体育消费人群都能快乐消费.     

无水硫酸钠校准-高频燃烧红外吸收法测定铜精矿中高含量硫

称取0.045 0 g铜精矿样品,加入坩埚中,再依次加入0.1 g锡、0.3 g铁和1.2 g钨,以无水硫酸钠标准物质建立校准曲线,建立了高频燃烧红外吸收法测定铜精矿中高含量硫的方法。实验表明:按称样量为0.045 0 g计算,方法空白值为0.005%,与铜精矿样品中硫的质量分数(均在5%以上)相比可忽略;以积分面积为横坐标,硫绝对含量为纵坐标绘制校准曲线,硫酸钠校准曲线的线性方程为y=37.37x-1.64,线性相关系数为0.999 96,线性适用范围为6.30%～36.50%。按照实验方法对铜精矿中高硫含量进行测定,结果与国家标准方法GB/T 3884.3-2012中的燃烧滴定法一致,相对标准偏差(RSD, n=5)不大于0.70%。     

The role of Peyer's patches in the age-related incidence of Crohn's disease

Recently researchers have suggested that clinical subsets of Crohn's disease occur, which are variously described as inflammatory, fibrostenotic, and fistulizing. In addition, it has been observed that within families with multiple cases, often there is concordance of the site and type of disease. The lesions of Crohn's disease occur in segments that suggest that distribution of Peyer's patches. When the age-related incidence of Crohn's disease was plotted for all countries from which such data were available, the peaks of greatest case frequency occurred at ages 15 to 25 years and paralleled a similar peak representing the number of Peyer's patches as a function of age. This correlation suggests that Crohn's disease may develop as an inflammatory process specifically targeting these important lymphoid structures. Similar peaks of activity in the adolescent to early adult years occur for appendicitis and tonsillitis.     

The role of sulfur in the air embrittlement of nickel and its alloys

A mechanism leading to the embrittlement of nickel and its alloys following high temperature air exposure is proposed. This mechanism involves the internal oxidation of sulfides to oxides, accompanied by a release of embrittling sulfur onto the grain boundaries. The mechanism is shown to work in a model system of nickel containing MnS precipitates, in which a ring of internal oxidation 250 μm in depth forms during 200 hours air exposure at 1000 °C. Auger analysis shows very high sulfur levels on grain boundaries within this region, but also reveals considerable sulfur concentrations beyond it. This massive release of free sulfur had the effect of rendering the alloy brittle over the entire temperature range investigated (25 to 1000 °C). The contribution of this mechanism to the known air embrittlement of pure nickel (Ni270) and a nickel base superalloy (IN738) is investigated. Although enhanced O/Ni peak height ratios were observed in the air exposed samples of both materials, the only significant sulfur concentrations were observed on the surfaces of grain boundary cavities formed in Ni270. However, the starting sulfur levels were extremely low in both cases, and the mechanism may contribute to high temperature air embrittlement in other systems. R.A. MULFORD, formerly with the General Electric Corporate Research and Development Laboratory, Schenectady     

Pattern formation in epithelial development: the vertebrate limb and feather bud spacing

The ectoderm of the vertebrate limb and feather bud are epithelia that provide good models for epithelial patterning in vertebrate development. At the tip of chick and mouse limb buds is a thickening, the apical ectodermal ridge, which is essential for limb bud outgrowth. The signal from the ridge to the underlying mesoderm involves fibroblast growth factors. The non-ridge ectoderm specifies the dorsoventral pattern of the bud and Wnt7a is a dorsalizing signal. The development of the ridge involves an interaction between dorsal cells that express radical fringe and those that do not. There are striking similarities between the signals and genes involved in patterning the limb ectoderm and the epithelia of the Drosophila imaginal disc that gives rise to the wing. The spacing of feather buds involves signals from the epidermis to the underlying mesenchyme, which again include Wnt7a and fibroblast growth factors.     

Binding constants in the formation of mammalian protein synthesis initiation complexes and the role of mRNA

Acute idiopathic thrombocytopaenic purpura is the most common of the thrombocytopaenias of childhood. Clinically it is associated with petechiae, mucocutaneous bleeding and occasionally haemorrhage into tissues. The oral mucosa is frequently involved. This paper describes a case presenting in general dental practice.     

The role of Gi-proteins and beta-adrenoceptors in the age-related decline of contraction in guinea-pig ventricular myocytes

A decline in contractility in myocytes from ageing guinea-pig hearts was demonstrated, which is more pronounced for maximum beta-adrenoceptor-stimulated activity than contraction in high Ca2+. In this study the role of the inhibitory G-proteins (Gi) in this process was investigated. Comparisons were made between young (Y, < 400 g, < 4 weeks), adult (A. > 600 g, > 8 weeks) and senescent guinea pigs (S, 58-65 weeks, 1136 +/- 30 g). Gi alpha activity, detected by pertussis toxin-catalysed ADP ribosylation, was significantly increased in senescent compared to young animals, but immunodetectable levels of Gi alpha were unchanged, beta-adrenoceptor number was decreased by 27% in senescent compared with young animals (P < 0.002). Pertussis toxin treatment increased the maximum response to isoproterenol in contacting myocytes so that there was no longer any significant decline with age. Maximum contraction amplitudes (sarcomere length change, micron) with isoproterenol before pertussis toxin were 0.144 +/- 0.011 (Y, n = 22 animals), 0.104 +/- 0.009 (A. 18) and 0.098 +/- 0.009 (S. 14), P < 0.01 by analysis of variance (ANOVA). Following toxin treatment amplitudes were 0.140 +/- 0.012 (Y. 12), 0.117 +/- 0.010 (A. 10) and 0.117 +/- 0.018 (S. 8), P = N.S. Pertussis toxin treatment also reversed the effects of ageing on contraction and relaxation velocity in isoproterenol. In contrast, the effect of age on contraction amplitude or velocity in maximum Ca2+ was more pronounced after toxin treatment. The EC50 value for isoproterenol increased with age: pertussis treatment decreased the EC50 in each group, but the effect was especially pronounced for senescent animals. There was no significant difference in the concentration-response curves for the negative inotropic effect of adenosine (in the presence of isoprotenerol) between the three age groups before toxin treatment. All effects of adenosine were abolished after pertussis exposure. We conclude that increased Gi alpha activity is likely to contribute to the decreased response to isoproterenol, but not to high Ca2+, in myocytes from ageing guinea-pigs.     

The role of sodium in the accelerated oxidation phenomenon termed sulfidation

The accelerated oxidation behavior (sulfidation) of commercial nickel-base alloys and simple binary alloys coated with either Na₂SO₄ or Na₂CO₃ was studied. The accelerated rates of oxidation associated with sulfidation are related to the oxide-ion content of the fused salt; and aluminum plays a major role in determining whether an alloy is susceptible to this attack.     

Stability of chromium (III) sulfate in atmospheres containing oxygen and sulfur

The stability of chromium (III) sulfate in the temperature range from 880 to 1040 K was determined by employing a dynamic gas-solid equilibration technique. The solid chromium sulfate was equilibrated in a gas stream of controlled SO₃ potential. Thermogravimetric and differential thermal analyses were used to follow the decomposition of chromium sulfate. Over the temperature range studied, the change in the Gibbs’ free energy of formation of chromium sulfate Cr₂O₃(s) + 3SO₃(g) → Cr₂(SO₄)₃(s) can be expressed as ΔG⁰ = •143,078 + 129.6T (±300) cal mole^•1 ΔG⁰ = •598,350 + 542T (±1250) J mole^•1. X-ray diffraction analysis indicated that the decomposition product was crystalline Cr₂O₃ and that the mutual solubility between Cr₂(SO₄)₃ and Cr₂O₃ was negligible. Over the temperature range investigated, the decomposition pressures were significantly high so that chromium sulfate is not expected to form on commercial alloys containing chromium when exposed to gaseous environments containing oxygen and sulfur (such as those encountered in coal gasification).     

The role of histamine in platelet aggregation by physiological and immunological stimuli

This paper reviews the current state of the debate on the relationship between mental disorder and violent behaviour. Starting from the discussion of methodological approaches to assessing a possible association, the most important studies carried out on the issue in recent years are discussed. Their results concur in supporting the assumption that there is a moderate but reliable association between mental disorder and violence. However, this does not imply that people with mental illness are generally more likely to commit violent acts than members of the general population. An elevated risk of violent behaviour is only evident for specific psychiatric diagnoses and for particular symptom constellations. For schizophrenia and other psychotic disorders, a significant increase in the likelihood to commit violent acts is reported. Substance use disorder and antisocial personality disorder, however, represent a markedly higher risk for violent behaviour. The article further discusses possible determinant of violent behaviour such as psychotic symptoms and comorbidity with substance abuse, and considers who is at particular risk of becoming a target of violent acts.     

The age-related characteristics of the effect of dimethylsulfoxide on myocardial catalase activity in immobilization stress

The effect of intraperitoneal injection of dimethyl sulfoxide (DMSO) in a dose of 175 mg/kg on the catalase activity of the myocardium of adult and old-aged rats subjected to immobilization stress was studied. DMSO injection promoted catalase activation in the heart of old-aged rats subjected to immobilization and practically had no effect on the analogous parameter in adult animals. Together with activation of the enzyme, changes occur in it which raise the effectiveness of the catalase response under conditions of stimulated production of active forms of oxygen in oxidation stress (increased affinity for the substrate, more expressed changes in activity in response to a change in pH of the medium, limited effect of the inhibitors on the enzyme).     

External respiration as an index of the individual physiological characteristics of higher nervous activity in rats

The signals for targeting and assembly of porin, a protein of the mitochondrial outer membrane, have not been clearly defined. Targeting information has been hypothesized to be contained in the N-terminus, which may form an amphipathic alpha-helix, and in the C-terminal portion of the protein. Here, the role of the extreme N- and C-termini of porin from Neurospora crassa in its import into the mitochondrial outer membrane was investigated. Deletion mutants were constructed which lacked the N-terminal 12 or 20 residues or the C-terminal 15 residues. The porins truncated at their N-termini were imported in a receptor-dependent manner into the outer membrane of isolated mitochondria. When integrated into the outer membrane, these preproteins displayed an increased sensitivity to protease as compared to wild-type porin. In contrast, mutant porin truncated at its C-terminus did not acquire protease resistance upon incubation with mitochondria. Thus, unlike most other mitochondrial preproteins, porin appears to contain important targeting and/or assembly information at its C-terminus, rather than at the N-terminus.     

The role of neutrophils in peritoneal adhesion formation

The most common cause of intraperitoneal adhesions is previous abdominal surgery. Postoperative adhesion formation results from a fibroproliferative inflammatory reaction that begins with an influx of polymorphonuclear leukocytes (PMNs) into the peritoneal cavity. Adherence of the PMNs to the endothelial cells (EC) is necessary for PMN migration into the tissue in response to a stimulus. Several receptor-counterreceptor pairs of ligands such as CD11/CD18 on the PMN and ICAM-1 (CD54) on EC have been identified. Monoclonal antibody against CD11/CD18 (R15.7) inhibits PMN adherence and migration and consequently protects against PMN-induced tissue injuries. We therefore studied the effect of preventing PMN-EC adherence, using anti-CD18 monoclonal antibody, on postoperative adhesion formation in rabbits. Group 1 was a control receiving physiologic saline, and group 2 received anti-CD18 antibody (R15.7, 2 mg/kg). The treatment was administered iv at the end of surgery and repeated on the first and second postoperative days. Peritoneal adhesions were induced at laparotomy by repairing two peritoneal defects, by oversewing the defect (model 1), and by resuturing the removed parietal peritoneum in its place as an ischemic graft (model 2). Adhesions were evaluated blindly at 10 days after operation by measuring the percentage of the suture line covered with adhesions (model 1) or by a scoring system (model 2). All control animals developed intraperitoneal adhesions and the percentage of the suture line covered with adhesions was 25 +/- 5.9% (mean +/- SEM) and the mean score in model 2 was 0.9 +/- 0.2. Anti-CD18 antibody, R15.7, increased the degree of postoperative adhesion formation in both models, but the results were significant only in model 2. Also, anti-CD18 antibody significantly decreased peritoneal neutrophils from 11.1 x 10(7) +/- 1.8 x 10(7) to 2.2 x 10(7) +/- 0.4 x 10(7) (P < 0.001) on the first postoperative day. It is concluded that inhibition of PMN-EC adherence does influence the postoperative adhesion formation. These results might suggest that PMNs have a role in modulating postoperative adhesion formation.     

Neural correlates of age-related declines in the formation and realization of delayed intentions.

Neural correlates of age-related declines in prospective memory were studied by using event-related brain potentials (ERPs) in a task in which individuals formed and later realized simple intentions. The behavioral data revealed that prospective responding was less accurate and slower in older than in younger adults. The electrophysiological data revealed age-related differences in the amplitude of modulations of the ERPs associated with the encoding of intentions, the detection of cues, and disengagement from the ongoing activity. These findings support the hypothesis that age-related declines in prospective memory result from a reduction in the efficiency with which older adults encode intentions and detect cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of sodium lauryl sulfate on the phrenic nerve diaphragm preparation from the rat

Noncytotoxic CD8+ T cells may play a critical role in preventing progression to disease following human immunodeficiency virus (HIV) infection. This antiviral response, mediated by a novel CD8+ T-cell antiviral factor (CAF), occurs soon after infection and is maintained in asymptomatic individuals. Here, Jay Levy and colleagues propose that this antiviral activity represents a natural cellular immune reaction that controls HIV production and protects the host from potential harmful effects of cytotoxic T lymphocytes.