The electrochemical reduction of oxygen on high surface area lithium doped nickel oxides

The electrochemical activity of high surface area lithiated nickel oxides, prepared by freeze-drying or hydroxide precipitation, towards the reduction of oxygen in KOH, was investigated as a function of surface are, temperature and oxygen partial pressure. For very high surface area oxides (180 m²/g) electrochemically reversible behaviour was achieved at 150 instead of 230°C for the lower surface area oxides. The evidence suggests that oxygen is being reduced directly to hydroxyl ions without forming the peroxide intermediate. The results concur with the Joint Pseudosplitting/Dissociative Adsorption mechanism proposed by Evans, and also provide further evidence that the temperature at which oxygen is dissociatively chemisorbed on lithiated nickel oxides may be related to the Neel Temperature.     

Stress analysis of crazes at moving crack tips

Summary The finite element method is applied to contours of craze zones in front of moving crack tips in polymethylmethacrylate (PMMA), measured by interferometry, in order to compute the stress distribution. In contrast to the constant stress assumed in the Dugdale model, a stress distribution is found with a maximum at the crack tip then a sharp decrease and a more gradual decline over the larger part of the craze length. Computed stresses as well as the Dugdale stress increase with increasing crack speed and, hence, decreasing loading time. Generally the results obtained are in good agreement with those already found for growing crazes at stationary crack tips.     

Pre-operative aspirin decreases platelet aggregation and increases post-operative blood loss--a prospective, randomised, placebo controlled, double-blind clinical trial in 100 patients with chronic stable angina

Aspirin has an established benefit in reducing the incidence of coronary events and vein graft occlusion. We have now assessed the risk of pre-operative aspirin in a prospective, randomised, double-blind clinical trial in 100 patients scheduled for elective coronary artery surgery. Any prescribed aspirin and non-steroidal anti-inflammatory drugs were discontinued 2 weeks pre-operatively and these were replaced by a randomly assigned tablet of either aspirin 300 mg daily or placebo taken until the day of surgery. Patient compliance was confirmed by serum and urinary salicylate analysis. The two groups were similar in demographic characteristics, bypass time, number of grafts placed and number of internal mammary arteries used. All patients survived to be discharged home (see Table). Aspirin decreases platelet aggregation to arachidonic acid and to collagen both pre- and post-operatively. The benefit of pre-operative aspirin has to be balanced against the risk of increasing post-operative blood loss, re-exploration for excessive bleeding and transfusion requirements.     

Influence of aging on the pharmacokinetics and pharmacodynamics of doxacurium

OBJECTIVE: Different sets of diagnostic criteria have been proposed for Sj?gren's syndrome (SS), but none have been validated with a large series of patients or in a multicenter study. We conducted the present study involving 26 centers from 12 countries (11 in Europe, plus Israel), with the goals of reaching a consensus on the diagnostic procedures for SS and defining classification criteria to be used in epidemiologic surveys and adopted by the scientific community. METHODS: The study protocol was subdivided into two parts. For part I, questionnaires regarding both ocular and oral involvement were developed; they included 13 questions and 7 questions, respectively. For part II a limited set of diagnostic tests was selected, and the exact procedure to be followed in performing these tests was defined. Part I of the study included 240 patients with primary SS and 240 age- and sex-matched controls. Two hundred forty-six patients with primary SS, 201 with secondary SS, 113 with connective tissue diseases but without associated SS, and 133 control patients were studied in part II. RESULTS: The study resulted in (a) the validation of a simple 6-item questionnaire for determination of dry eyes and dry mouth, which showed good discriminant power between patients and controls, to be used in the initial screening for sicca syndrome; and (b) the definition of a new set of criteria for the classification of SS. The sensitivity and specificity of the criteria in correctly identifying patients with either the primary or the secondary variant of SS were also determined. CONCLUSION: Using the findings of this prospective multicenter European study, general agreement can be reached on the diagnostic procedures to be used for patients with SS. Final validation of the preliminary classification criteria for SS is underway.     

Vortex Mutual Friction in Superfluid 3He

We give a full account of our extensive measurements of vortex mutual friction in rotating superfluid ³He, in both the A- and B-phases. The B-phase results are in qualitative agreement with a theory based on the concept of “spectral flow”; the agreement becomes quantitative if an effective energy gap of 0.63 Δ is used, but the Justification for such a substitution is not clear. The vortex core transition, at first not seen because of metastability and hysteresis, has now been observed. Detailed investigation suggests that the high temperature vortex state is a temperature dependent mixture of at least two vortex types. The A-phase mutual friction is found to be well described by two hydrodynamic coefficients, the orbital viscosity and the orbital inertia. The latter corresponds to an orbital angular momentum per Cooper pair of (0.0015 ± 0.0017 ) ħ, consistent with the prediction of the spectral flow theory. We find that the most uniform l texture is obtained by cooling through T_c while rotating, and then stopping rotation. Detailed investigation of textural memory effects shows that the uniform l-up and l-down textures are associated with opposite directions of rotation. We discuss the various types of texture that may be formed in our experiments. Finally, we compare our mutual friction results with those found in ⁴HeII.     

Impaired processing of proopiomelanocortin in corticotroph macroadenomas

The p53 mutations in the reported 243 lung cancers and our 59 cases were analyzed. The common base substitutions found in the lung cancer were G to T transversion (35%), C:G to T:A (26%) and A:T to G:C transitions (11%). Four types of the hot spot, 1) G to T transversion, 2) A to G transition in ApT site, 3) C to T transition in CpG site and 4) mix of the transversion and transition were identified. It is suggested that A to G transition at ApT site in the non-transcribed strand may be a new hot spot in the p53 gene in lung carcinoma. We also show that microscopic selection of cancer cells will facilitate the detection of p53 mutations in adenocarcinomas.     

Antigen-specific and nonspecific deletion of immature cortical thymocytes caused by antigen injection

Analysis of antigen-induced negative selection of thymocytes in T cell receptor (TCR)-transgenic mice is complicated by the presence of an antigen-responsive peripheral T cell compartment. Our experiments address the question of whether and how peripheral T cell activation can affect immature thymocytes. Following three daily injections of peptide antigen into mice expressing a peptide-specific transgenic TCR and deficient for TAP1, we and others have found profound deletion of the CD4+CD8+ (DP) thymocyte subset. However, our work shows that even though mature CD8+ T cells are inefficiently selected in TAP1-deficient mice, there was a striking degree of peripheral expansion and activation of CD8+ peripheral T cells. Furthermore, when cells from TCR-transgenic mice were adoptively transferred, we found that deletion of nontransgenic DP thymocytes occurred in Thy-1-congenic and even more efficiently in TAP1-deficient recipients after repeated peptide injection resulting in peripheral T cell activation. In the adoptive transfer experiments the degree of deletion of immature bystander thymocytes was decreased upon blocking of TNF. These data show that deletion of DP thymocytes can result from excessive peripheral T cell activation and identify TNF as an important effector molecule for this process. When steps are taken to avoid peripheral T cell activation, peptide antigen can induce TCR-mediated thymocyte deletion, presumably in the thymus cortex, since injection of TAP1-deficient TCR-transgenic mice resulted in deletion of immature DP thymocytes prior to detectable peripheral T cell expansion and activation. This effect was not blocked by inhibiting tumor necrosis factor activity. In addition, DP depletion was seen in the absence of peripheral T cell activation when antibody-mediated depletion of CD8+ T cells was performed. Our work clearly shows that two mechanisms for deletion of DP thymocytes exist: deletion induced by antigen presentation in the thymus and deletion as a consequence of repeated stimulation of mature peripheral T cells.     

Subliminal stimulation: A pervasive problem for psychology.

After a brief historical introduction and a discussion of methodological issues, this substantive review concentrates upon the relevant literature of the past 5 years. Special attention is given to the writer's own experiments on the effect of subliminal anchors upon psychophysical judgments. (67 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sound-precipitated convulsions: 1947-1954.

Approximately 129 papers on audiogenic seizure are examined. Among the variables influencing seizure susceptibility are audition, intense light, pain, temperature, regulation of free movement, opportunity for escape; genetic, age and sex, and physiological status differences; and psychological status. "Perhaps the most promising developments are concerned with the inheritance of susceptibility in mice, stimulus priming, and learned control of the seizure." 145 references. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biohydrogen production from Imperata cylindrica bio-oil using non-stoichiometric and thermodynamic model

This paper presents a non-stoichiometric and thermodynamic model for steam reforming of Imperata cylindrica bio-oil for biohydrogen production. Thermodynamic analyses of major bio-oil components such as formic acid, propanoic acid, oleic acid, hexadecanoic acid and octanol produced from fast pyrolysis of I. cylindrica was examined. Sensitivity analyses of the operating conditions; temperature (100–1000 °C), pressure (1–10 atm) and steam to fuel ratio (1–10) were determined. The results showed an increase in biohydrogen yield with increasing temperature although the effect of pressure was negligible. Furthermore, increase in steam to fuel ratio favoured biohydrogen production. Maximum yield of 60 ± 10% at 500–810 °C temperature range and steam to fuel ratio 5–9 was obtained for formic acid, propanoic acid and octanol. The heavier components hexadecanoic and oleic acid maximum hydrogen yield are 40% (740 °C and S/F = 9) and 43% (810 °C and S/F = 8) respectively. However, the effect of pressure on biohydrogen yield at the selected reforming temperatures was negligible. Overall, the results of the study demonstrate that the non-stoichiometry and thermodynamic model can successfully predict biohydrogen yield as well as the composition of gas mixtures from the gasification and steam reforming of bio-oil from biomass resources. This will serve as a useful guide for further experimental works and process development.