Phase equilibria and crystal structures in the ternary systems: Actinoid metal-transition metal-boron III. Ternary transition metal diborides with plutonium

Ternary borides PuTB₄ and Pu₂TB₆ have been synthesized from the elements and their crystal structures have been characterized from X-ray powder diffraction data. Compounds PuTB₄ with T = Mo, W, Tc, Re crystallize in the orthorhombic YCrB₄-type, whereas PuRuB₄ and PuOsB₄ reveal a transposition behavior between the related structure types of YCrB₄ and ThMoB₄. Compounds Pu₂TB₆ with T = Tc, Re, Ru, and Os are isostructural with the structure type of Y₂ReB₆. The crystal chemistry of these phases is discussed with respect to the corresponding rare earth compounds.     

Sequence analysis of the putative viral enhancer in tissues from 33 cats with various feline leukemia virus-related diseases

INTRODUCTION: The incidence of shigellosis in Israel was fairly stable until around 1974, when it gradually began to increase to a peak in 1985. This was accompanied by a shift in the maximum incidence in the Jewish population from the age group < 1 to 1-4 years. AIM: To update the epidemiology of shigellosis in Israel 1986-1995. METHODS: Only laboratory-confirmed cases of shigellosis in the civilian population were analyzed. Data were obtained from the weekly reports of the subdistricts. Antibiotic sensitivity data were obtained from several hospitals and the General Workers' Sick Fund laboratories in Jerusalem, Haifa, and Tel Aviv. RESULTS: From 1986 to 1991, shigellosis incidence per 100,000 decreased by about 50%, and the decrease occurred mainly in the Jewish population. Several regional outbreaks in 1992 reversed this decline, but by 1995, the incidence was similar to that observed prior to 1974. The disease still occurs mainly in the summer, with an occasional winter outbreak. Higher incidence rates occurred in the northern subdistricts. The peak incidence in the non-Jewish population moved from the < 1-year-olds to the 1-4 year-old group, similar to the pattern in the Jewish population in 1970. In 1991, for the first time, the rate in the age group 5-9 years among non-Jews exceeded that of those < 1 year old. Marked decreases in sensitivity to several antibiotics were found in peripheral and hospital laboratories. An increase in the sensitivity to tetracycline was noted since 1991. Case fatality rates remain low, with a mean of 0.05% for the decade of the 1980s. CONCLUSIONS: Shigellosis remains a highly endemic disease in Israel, but changes in the age-related peak incidence indicate that the pattern of spread is becoming more similar to other developed countries.     

Visual response time to colored stimuli in peripheral retina: evidence for binocular summation

Simple onset response time (RT) experiments, previously shown to exhibit binocular summation effects for white stimuli along the horizontal meridian, were performed for red and green stimuli along 5 oblique meridians. Binocular RT was significantly shorter than monocular RT for a 45-min-diameter spot of red, green, or white light within eccentricites of about 50 deg from the fovea. Relatively large meridian differences were noted that appear to be due to the degree which the images fall on corresponding retinal areas.     

A new perspective on de-individuation via computer-mediated communication

Research examining de-individuation via computer-mediated communication (CMC) suggests that group pressure is more pronounced in CMC-using groups than in groups meeting face to face, because CMC strips away non-verbal cues and makes individuals feel more similar to the others in their group. Similarly, electronic voting research suggests that group influence is more pronounced via group support systems when the opinions of others are communicated in real time. However, recent research involving complete anonymity suggests that group influence is mitigated via anonymous CMC because of a lack of awareness of others. Thus, we propose that increased group influence is facilitated when others’ opinions are communicated, and is heightened with the common identity created through the use of nominal labels. This paper reports the results of a laboratory experiment involving groups making an organization decision via a text-based chat room. The results show that a simple electronic voting interface element increased the amount of group influence on individual members, and led to decreased participation and higher dispensability.     

Electrochemically Powered,Energy‐Conserving Carbon Nanotube Artificial Muscles

While artificial muscle yarns and fibers are potentially important for many applications, the combination of large strokes, high gravimetric work capacities, short cycle times, and high efficiencies are not realized for these fibers. This paper demonstrates here electrochemically powered carbon nanotube yarn muscles that provide tensile contraction as high as 16.5%, which is 12.7 times higher than previously obtained. These electrochemical muscles can deliver a contractile energy conversion efficiency of 5.4%, which is 4.1 times higher than reported for any organic‐material‐based artificial muscle. All‐solid‐state parallel muscles and braided muscles, which do not require a liquid electrolyte, provide tensile contractions of 11.6% and 5%, respectively. These artificial muscles might eventually be deployed for a host of applications, from robotics to perhaps even implantable medical devices.     

Heme Degradation in Pathophysiology of and Countermeasures to Inflammation-Associated Disease

The class of tetrapyrrol “coordination complexes” called hemes are prosthetic group components of metalloproteins including hemoglobin, which provide functionality to these physiologically essential macromolecules by reversibly binding diatomic gasses, notably O₂, which complexes to ferrous (reduced/Fe(II)) iron within the heme porphyrin ring of hemoglobin in a pH- and PCO₂-dependent manner—thus allowing their transport and delivery to anatomic sites of their function. Here, pathologies associated with aberrant heme degradation are explored in the context of their underlying mechanisms and emerging medical countermeasures developed using heme oxygenase (HO), its major degradative enzyme and bioactive metabolites produced by HO activity. Tissue deposits of heme accumulate as a result of the removal of senescent or damaged erythrocytes from circulation by splenic macrophages, which destroy the cells and internal proteins, including hemoglobin, leaving free heme to accumulate, posing a significant toxicogenic challenge. In humans, HO uses NADPH as a reducing agent, along with molecular oxygen, to degrade heme into carbon monoxide (CO), free ferrous iron (FeII), which is sequestered by ferritin protein, and biliverdin, subsequently metabolized to bilirubin, a potent inhibitor of oxidative stress-mediated tissue damage. CO acts as a cellular messenger and augments vasodilation. Nevertheless, disease- or trauma-associated oxidative stressors sufficiently intense to overwhelm HO may trigger or exacerbate a wide range of diseases, including cardiovascular and neurologic syndromes. Here, strategies are described for counteracting the effects of aberrant heme degradation, with a particular focus on “bioflavonoids” as HO inducers, shown to cause amelioration of severe inflammatory diseases.     

The service architecture of the TeraGyroid experiment

We describe the service architecture of the successful TeraGyroid experiment. In particular we discuss the use of the open Grid service infrastructure (OGSI) to build the services used during the experiment and illustrate the problems we encountered.