Reaction to a placebo: The mediational deficiency hypothesis.

This paper reconsidered data previously interpreted as supporting the mediational deficiency hypothesis. It was concluded that: certain comparisons of theoretical similarities were unclear; inferences from "reversal-nonreversal" and "transposition" paradigms did not lead to unequivocal interpretations; and crucial evidence from research in deafness and from other theoretical positions, as Piaget's, were ignored. The reduction of the role of language in cognitive development to a verbal mediation construct was considered an oversimplification and a potential source of confusion. (18 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pharmacologic adjuvants to epoetin in the treatment of anemia in patients on hemodialysis

Anemia is a common complication of chronic kidney disease, particularly in patients who are on dialysis. The use of recombinant human erythropoietin has led to the eradication of severe anemia in the dialysis population. Correction of anemia in these patients has been associated with better quality of life and clinical outcomes. Some hemodialysis patients have anemia that either is relatively refractory to epoetin therapy or requires very high doses of epoetin (i.e., hyporesponsiveness), despite having adequate iron stores, and are thus unable to achieve or maintain target hemoglobin levels. Several pharmacologic agents have been studied for effects on improving response to epoetin, either to counter hyporesponsiveness or simply to reduce epoetin use for purely economic reasons. This review examines the available literature regarding the efficacy of these potential pharmacologic adjuvants to epoetin in the treatment of anemia in patients on maintenance hemodialysis, with special emphasis on androgens, vitamin C (ascorbic acid), and L-carnitine. A review of published guidelines and recommendations for use of these agents in hemodialysis patients is provided.     

Physicochemical and kinetic properties of purified sheep's milk xanthine oxidoreductase

Xanthine oxidoreductase (XOR) was purified for the first time from sheep's milk. The ultraviolet-visible absorption spectrum was essentially identical to those of the corresponding bovine, human, and goats' milk enzymes and showed an A280/A450 ratio of 5.35 +/- 0.24, indicating a high degree of purity. Like milk XOR from other species, sheep's milk enzyme showed a single band on SDS-PAGE corresponding to a subunit with approximate Mr 150,000. Xanthine oxidase activity of purified sheep's milk XOR (0.69 +/- 0.04 micromole urate min(-1) mg(-1)) was low relative to that of the bovine milk enzyme (1.83 +/- 0.02 micromole urate min(-1) mg(-1)), but higher than those of human or goats' milk XOR. As in the latter 2 cases, the low activity of sheep's milk XOR can be attributed to its relatively low molybdenum content (0.18 atoms per subunit), compared with that of the bovine milk enzyme (0.56 atoms Mo per subunit). Consistent with this, NADH oxidase activity of sheep's milk XOR was similar to that of enzymes purified from bovine, human, or goats' milk. The presence of desulpho-enzyme in sheep's milk XOR was demonstrated by resulfuration experiments, whereby xanthine oxidase activity was increased by approximately 75%.     

Trace nutrient deficiency in Daphnia magna cultured in standard medium for toxicity testing. Effects of the optimization of culture conditions on life history parameters of D. magna

The suitability of various synthetic media for the culture of Daphnia magna was tested. Daphnids cultured in a standard medium for toxicity testing proposed by ISO showed low reproduction, reduced growth, high numbers of undeveloped parthenogenetic eggs and high mortality of neonates and adults. As a feature, animals cultured in the ISO medium lost parts of their second antennae. It could be shown that this was caused by selenium deficiency. The addition of selenium to the ISO medium clearly improved the quality of this medium. However, results of several tests were more variable than when a medium with a complex trace element composition (medium M4) was used. Medium M4 has allowed continuous culture of daphnids for three years up to now without any signs of reduced viability or reproduction. A mean reproduction rate of about 140 progeny/parent daphnid was calculated from 19 non simultaneous experiments. Neither a fourfold increase nor a reduction to one tenth of the trace element concentration of M4 had any effect on reproduction, growth or survival of daphnids. It was shown in this study that ion-exchanger cartridges can leach detrimental substances into the matrix water. Therefore, only ultrapure matrix waters should be used for the preparation of culture media.     

Enhancing catalytic activity of NdFeO3 perovskite by tuning A-site cation deficiency for oxygen evolution reaction

Electrochemical water splitting got much attention because of its great promising electrochemical technology to generate sustainable and renewable energy resources. In this aim, we have prepared a novel series of electrocatalysts Nd_1-xFeO₃ (x = 0.0, 0.05, 0.1, 0.15) by sol-gel method. The effect of the deficiency in the A-site on the structure, morphology, surface and electrocatalytic activity of these perovskites were studied by means of XRD, XPS, MEB, LSV, EIS and chronopotentiometric measurements. Among all the samples, Nd_0.9FeO₃ (denoted NF10) exhibits the higher catalytic activity with a low overpotential of 370 mV at a current density of 10 mA cm^?2, a small Tafel slope of 79 mV dec^?1 and a good electrochemical stability in 1 M KOH solution. The OER performance of NF10 can be effectively enhanced by optimizing iron valence and highly oxidative oxygen species (O₂^2?/O^?) based on the surface of catalyst. The results of this study indicate that the NF10 electrocatalyst can be considered as a good candidate for the OER in alkaline media.     

猪苓中黄嘌呤氧化酶抑制剂的筛选分离及质谱分析

试验以猪苓为研究对象,综合利用遗传算法-BP神经网络数学模型、色谱和质谱等技术,建立快速筛选猪苓中黄嘌呤氧化酶抑制剂的新方法。首先,利用遗传算法-BP神经网络数学模型优化猪苓中麦角甾醇的提取工艺;其次,以黄嘌呤氧化酶为生物靶分子,应用超滤质谱技术,筛选猪苓中潜在的黄嘌呤氧化酶抑制剂,同时,应用分子对接技术验证超滤实验的准确性;最后,以活性筛选为导向,利用高速逆流色谱技术分离猪苓中黄嘌呤氧化酶抑制剂。结果显示：猪苓中麦角甾醇的最佳提取工艺为乙醇体积分数80%、液料比16 mL/g、提取时间1.4 h、提取次数3次,在此条件下,麦角甾醇得率为2.31%;从猪苓中筛选并分离出4个纯度均在90%以上的黄嘌呤氧化酶抑制剂,其抑制效果强弱顺序为猪苓酮A>猪苓酮B>麦角甾-4,6,8(14),22-四烯-3-酮>麦角甾-7,22-二烯-3-酮。该方法快速、灵敏,为猪苓抗痛风药理作用的进一步研究提供了一定的理论基础。     

Uncertainty of concrete strength in shear and flexural behavior of beams using lattice modeling

This paper numerically studied the effect of uncertainty and random distribution of concrete strength in beams failing in shear and flexure using lattice modeling, which is suitable for statistical analysis. The independent variables of this study included the level of strength reduction and the number of members with reduced strength. Three levels of material deficiency (i.e., 10%, 20%, 30%) were randomly introduced to 5%, 10%, 15%, and 20% of members. To provide a database and reliable results, 1000 analyses were carried out (a total of 24000 analyses) using the MATLAB software for each combination. Comparative studies were conducted for both shear- and flexure-deficit beams under four-point loading and results were compared using finite element software where relevant. Capability of lattice modeling was highlighted as an efficient tool to account for uncertainty in statistical studies. Results showed that the number of deficient members had a more significant effect on beam capacity compared to the level of strength deficiency. The scatter of random load-capacities was higher in flexure (range: 0.680–0.990) than that of shear (range: 0.795–0.996). Finally, nonlinear regression relationships were established with coefficient of correlation values (R²) above 0.90, which captured the overall load–deflection response and level of load reduction.     

Color vision assessment‐1: Visual signals that affect the results of the Farnsworth D‐15 test

The Farnsworth D‐15 test (D‐15) is commonly used to screen for moderate to severe congenital color vision deficiency. The aim of this study was to establish reliable D‐15 statistics for normal, deutan and protan subjects, and to investigate the different visual signals one can use to carry out the test, even in dichromats and rod monochromats. Six hundred and seventy‐four subjects were examined using the D‐15, the Colour Assessment and Diagnosis test and the Nagel anomaloscope. A rod monochromat and five dichromats were tested using the standard D‐15 protocol before the caps were separated into two groups and subjects were asked to repeat the task. D‐15 spectral radiance data, measured under D65 illumination, were used to estimate differences in photoreceptor excitations for each of the caps. When no crossings and up to two adjacent transpositions on the D‐15 results diagram are accepted as a pass, 100% of normal trichromats, 54% of deutans and 43% of protans pass the D‐15. A rod monochromat and two protanopes and deuteranopes were able to complete the D‐15 when the caps were separated into two groups, despite severe loss or even complete absence of color vision. When up to two adjacent transpositions are accepted 50% of color deficient subjects, some with severe red/green loss, pass the D‐15. While the D‐15 is normally used to screen for moderate to severe color deficiency, subjects with severe loss can still use combined, residual red/green, yellow/blue and luminance signals to pass.     

Color vision assessment‐2: Color assessment outcomes using single and multi‐test protocols

The main purpose of this study was to produce reliable, color assessment outcomes to examine the extent to which single and multi‐test protocols in use meet current clinical and occupational needs. The latter include the detection of small changes in chromatic sensitivity as the earliest signs of retinal and/or systemic disease, and the need to assess the class of color vision in congenital deficiency and to quantify severity of loss. Color vision was assessed using Ishihara (IH), Farnsworth Munsell D‐15, City University (CU, 2nd ed.) and Holmes‐Wright type A (HW‐A) lantern tests. All subjects also carried out Colour Assessment and Diagnosis and Nagel anomaloscope tests. The sample included 350 normal trichromats, 1012 deutans and 465 protans (age 31.1 ± 12.4, range 10‐65 years). The results reveal the trade‐off between sensitivity and specificity, depending on the number of errors accepted as a pass on the IH test. The D‐15 and CU tests pass all normals and almost 50% of subjects with color vision deficiency. The HW‐A lantern passes all normals, 22% of deutans and 1% of protans. The multi‐test protocols designed to identify protans and to pass only subjects with mild color loss, pass over 50% of protans and deutans. Many of the subjects who fail exhibit less severe loss of color vision than others who pass. When high sensitivity for detection of congenital deficiency is achieved, single‐test protocols fail many normal trichromats. Multi‐test protocols produce large variability and fail to achieve desired aims.     

Dust cloud explosion characteristics and mechanisms in MgH2-based hydrogen storage materials

The mechanisms involved in premixed magnesium and hydrogen hybrid and synthetic MgH₂ dust cloud explosions were investigated. The results revealed that trace amounts of H₂ in Mg explosions can markedly increase explosion severity. Furthermore, H₂ addition can weaken the influence of oxygen deficiency on Mg explosion. Moreover, the explosion intensity of synthetic MgH₂ was far stronger than that of premixed Mg/H₂ mixture or Mg alone because the vacancy defects in Mg and H atoms can form after dehydrogenation of MgH₂, which caused that Mg and H₂ are prone to oxidation and nitrification in air atmosphere at a low temperature, thereby promoting the explosion. This demonstrates that the explosion risk of MgH₂ (even other H₂ storage materials) is related to its H₂ storage capacity and dehydrogenation temperature. Therefore, for H₂ storage materials, the better H₂ storage performances can exhibit higher explosion risks.