Error probability of binary NFSK and DPSK with postdetectioncombining over correlated Rician channels

For binary noncoherent orthogonal frequency-shift keying and binary differential phase-shift keying over slow nonselective Rician fading channels having arbitrarily correlated branches and unequal branch powers, a closed-form expression for the symbol-error probability in the case of postdetection equal-gain combining is obtained directly from the characteristic function of the decision variable     

A Modular Access Control Service for Supporting Application-Specific Policies

Access control services integrated in current middleware technologies fall short whenever application-specific access control policies must be enforced. As a consequence, developers embed access control logic in the code, resulting in an unmaintainable access control enforcement. The authors use aspect-oriented software development techniques to better separate application logic and access control by describing the design and implementation of a modular access control service. They have implemented a prototype in CaesarJ, a research aspect-oriented programming language.     

Protective Effect of Dietary Ghrelin‐Containing Salmon Stomach Extract on Mortality and Cardiotoxicity in Doxorubicin‐Induced Mouse Model of Heart Failure

Ghrelin exhibits a cardioprotective effect. We examined whether orally administered ghrelin‐containing salmon stomach extract (sSE) instead of chemically synthesized ghrelin protects against doxorubicin (DOX)‐induced cardiotoxicity in mice. Mice were divided into four groups: (i) the control, (ii) DOX groups were fed a control diet (AIN‐93G), (iii) the sSE, and (iv) DOX + sSE groups were fed a 10% sSE diet (AIN‐93G + 10% sSE). After a 4‐week pretreatment of sSE, DOX or saline was administered to the corresponding groups by intraperitoneal injection. The groups fed the 10% sSE diet consumed significantly more food than the groups fed the control diet before the DOX injection. No mortality was observed in the DOX + sSE group, whereas 40% (2 of 5) mortality was observed in the DOX group. Compared with the DOX group, levels of ascites and plasma cardiac troponin I improved in the DOX + sSE group. Significantly lesser DOX‐induced collagen accumulation was observed in the left heart ventricle of the DOX group than in that of the DOX + sSE group. These results suggest that the dietary ghrelin contained in sSE mimics synthetic ghrelin in cardioprotective effect. Ghrelin in sSE (45 pmol/g) and the food intake‐stimulating effect of sSE may explain, at least in part, the protective effect of orally administered teleost ghrelin.     

Increased bile acid pool inhibits cholesterol 7 alpha-hydroxylase in cholesterol-fed rabbits

BACKGROUND & AIMS: Cholesterol feeding unexpectedly inhibits cholesterol 7 alpha-hydroxylase in rabbits. The aim of this study was to explore the mechanism. METHODS: Twenty male New Zealand white rabbits were fed regular chow with and without 2% cholesterol for 10 days followed by 7 days of bile drainage. The activities of hepatic cholesterol 7 alpha-hydroxylase and sterol 27-hydroxylase that control bile acid synthesis in classic and alternative pathways were related to the size and composition of bile acid pool. RESULTS: After feeding cholesterol, plasma and hepatic cholesterol concentrations increased, the bile acid pool doubled (from 254 +/- 44 to 533 +/- 51 mg; P < 0.001), cholesterol 7 alpha-hydroxylase activity decreased 68% (P < 0.01), but sterol 27-hydroxylase activity increased 66% (P < 0.05) with increased cholic acid synthesis (P < 0.01). Bile drainage in the cholesterol-fed rabbits depleted the bile acid pool and stimulated down-regulated cholesterol 7 alpha-hydroxylase activity 11.4-fold (P < 0.001), although hepatic cholesterol remained elevated. Hepatic sterol 27-hydroxylase activity was unaffected. CONCLUSIONS: Feeding cholesterol increased hepatic cholesterol and stimulated sterol 27-hydroxylase and alternative bile acid synthesis, which expanded the bile acid pool and inhibited cholesterol 7 alpha-hydroxylase in rabbits. In distinction, hepatic sterol 27-hydroxylase was insensitive to changes in the bile acid pool.     

Determination of the glycoalkaloid content of potato tubers by three methods including enzyme-linked immunosorbent assay

Potato tuber samples of diverse genetic backgrounds were analysed independently for total glycoalkaloid content by three different procedures. Two of the methods used were conventional chemical assays, the third an enzyme-linked immunosorbent assay (ELISA). Agreement between all three was extremely good, though the ELISA employed much simpler sample preparation, was technically easier to carry out, and could assay more rapidly large numbers of samples. For these and other reasons, the ELISA will find wider application in future.     

Markedly increased tissue concentrations of 7-dehydrocholesterol combined with low levels of cholesterol are characteristic of the Smith-Lemli-Opitz syndrome

The Smith-Lemli-Opitz syndrome is an autosomal recessive birth defect (frequency 1:20,000-1:40,000) that results in profound mental retardation, physical deformities, and failure to thrive. It is characterized biochemically by low plasma cholesterol and greatly elevated levels of two dehydrocholesterols, one of which is the cholesterol precursor 7-dehydrocholesterol. To determine whether the block in cholesterol biosynthesis affects tissue sterols, we assayed several organs from two affected individuals, a female who died at 27 hours and a 20-week male fetus. Cholesterol concentrations in abdominal wall, adrenal gland, and kidney from two or three unaffected fetuses, who served as controls, averaged 2.0, 1.5, and 1.4 mg/g wet weight, compared to 0.08, 0.44, and 0.14, respectively, for the homozygous fetus. Cerebral cortex cholesterol concentrations were 2.2 mg/g for two 20-22-week fetal controls but only 0.21 and 0.09 mg/g, respectively, for the homozygous child and fetus. Similarly, tissue cholesterol levels were abnormally low in the homozygous child being less than 1 mg/g in liver, adipose, thymus, muscle, and adrenal and 6.2 mg/dl in plasma. Dehydrocholesterols could not be detected by conventional means in any controls but were elevated enough in tissues from affected individuals to make total sterol concentrations nearly normal. These results suggest that a defect in 3 beta-hydroxysterol delta 7-reductase leads to both a profound lack of cholesterol and its replacement by dehydrocholesterols. Such a combination may be lethal in the most severely affected individuals.     

Unified Analysis of UWB Transmitted-Reference Schemes in the Presence of Narrowband Interference

Transmitted-Reference (TR) signaling, in conjunction with an autocorrelation receiver (AcR), offers a low- complexity alternative to Rake reception in ultrawide bandwidth systems. This paper provides a unified performance analysis of various TR schemes by developing an analytical framework based on the sampling expansion approach. Specifically, we derive the uncoded bit error probability (BEP) of different TR signaling schemes, including TR and differential TR (DTR) signaling valid for a broad class of fading channels. We consider both AcRs and modified AcRs with noise averaging. We further develop a quasi-analytical method as well as an approximate analytical method to extend the BEP analysis to include the effect of narrowband interference (NBI). We show that the approximate analytical method is particularly useful in obtaining BEP expressions that provide insight into the effect of NBI. We quantify the effects of NBI and channel power dispersion profile on the optimum integration interval of an AcR. Finally, we compare TR and DTR signaling in terms of their sensitivity to NBI.     

Assessment of a bidirectional reflectance distribution correction of above-water and satellite water-leaving radiance in coastal waters

Water-leaving radiances, retrieved from in situ or satellite measurements, need to be corrected for the bidirectional properties of the measured light in order to standardize the data and make them comparable with each other. The current operational algorithm for the correction of bidirectional effects from the satellite ocean color data is optimized for typical oceanic waters. However, versions of bidirectional reflectance correction algorithms specifically tuned for typical coastal waters and other case 2 conditions are particularly needed to improve the overall quality of those data. In order to analyze the bidirectional reflectance distribution function (BRDF) of case 2 waters, a dataset of typical remote sensing reflectances was generated through radiative transfer simulations for a large range of viewing and illumination geometries. Based on this simulated dataset, a case 2 water focused remote sensing reflectance model is proposed to correct above-water and satellite water-leaving radiance data for bidirectional effects. The proposed model is first validated with a one year time series of in situ above-water measurements acquired by collocated multispectral and hyperspectral radiometers, which have different viewing geometries installed at the Long Island Sound Coastal Observatory (LISCO). Match-ups and intercomparisons performed on these concurrent measurements show that the proposed algorithm outperforms the algorithm currently in use at all wavelengths, with average improvement of 2.4% over the spectral range. LISCO's time series data have also been used to evaluate improvements in match-up comparisons of Moderate Resolution Imaging Spectroradiometer satellite data when the proposed BRDF correction is used in lieu of the current algorithm. It is shown that the discrepancies between coincident in-situ sea-based and satellite data decreased by 3.15% with the use of the proposed algorithm. This confirms the advantages of the proposed model over the current one, demonstrating the need for a specific case 2 water BRDF correction algorithm as well as the feasibility of enhancing performance of current and future satellite ocean color remote sensing missions for monitoring of typical coastal waters.     

RIE‐induced carrier lifetime degradation

Reactive Ion Etching (RIE) is used in the fabrication of some types of solar cells to achieve a highly directional etch. However, cells fabricated using RIE have lower than expected efficiency, possibly caused by increased carrier recombination. Characterisation of the carrier lifetime in solar cells was conducted using the quasi steady state photoconductance (QSSPC) measurement technique. Substantial effective lifetime degradation was observed for silicon samples processed by RIE. Lifetime degradation for samples where RIE etches into silicon is found to be permanent, while for samples where RIE etches only on dielectric layers of SiO₂ grown on the wafer, the lifetime degradation is found to be reversible. The reversible degradation in RIE‐processed samples is associated with radiation damage. By reducing the proportion of a wafer exposed to RIE, the degradation of the effective lifetime of RIE‐etched silicon samples can be minimised, and the performance of silicon solar cells can be improved significantly. Copyright © 2010 John Wiley & Sons, Ltd.