Carbonyl mediated conductance through metal bound peptides: a computational study

Large increases in the conductance of peptides upon binding to metal ions have recently been reported experimentally. The mechanism of the conductance switching is examined computationally. It is suggested that oxidation of the metal ion occurs after binding to the peptide. This is caused by the bias potential placed across the metal-peptide complex. A combination of configurational changes, metal ion involvement and interactions between carbonyl group oxygen atoms and the gold leads are all shown to be necessary for the large improvement in the conductance seen experimentally. Differences in the molecular orbitals of the nickel and copper complexes are noted and serve to explain the variation of the improvement in conductance upon binding to either a nickel or copper ion.     

Trimming CMOS smart imager with tunnel-effect nonvolatile analogue memory

Amplified MOS imagers (AMIs) have the advantage of being compatible with conventional CMOS analogue/digital circuit design. One of the major problems in AMIS is their large fixed pattern noise compared to CCD imagers. The Letter presents the structure of a nonvolatile tunnel-effect analogue memory which is fully compatible with a standard CMOS process and which can reduce significantly the offset-like fixed pattern noise in AMI arrays.<>     

The transmission of parent/adult-child drinking patterns: testing a gender-specific structural model

A structural model on parent/adult-child alcohol use patterns was examined. Three analytical blocks were specified: adult-children's alcohol use onset by types of alcoholic beverage, their current use of these alcoholic beverages, and parents' drinking patterns. The model was examined with data collected from drunken driving offenders in California and Maryland treatment programs. The findings indicate that parent/child alcohol use transmission is more gender specific than race specific; fathers' drinking tends to affect sons' drinking and mothers' drinking tends to affect daughters' drinking. Beer use onset is the earliest and more effective in influencing future alcohol use than the onset of wine or liquor.     

Nonepileptic seizures and childhood sexual and physical abuse

Nonepileptic seizures (NES) must be distinguished from epilepsy to avoid the adverse effects of unnecessary antiepileptic drugs and to initiate appropriate psychiatric treatment. A higher frequency of prior sexual abuse has been suspected in NES, although no prospective controlled study has compared patients with NES and epilepsy. A series of patients with conversion disorder presenting as epilepsy and 140 patients with complex partial epilepsy (CPE) without evidence of conversion were selected from a series of consecutive admissions to a comprehensive epilepsy center. The groups did not differ with respect to age, years of education, race, or marital status, but the percentage of women was greater in the conversion NES group (73.2%) than in the CPE control group (50.7%; p < 0.002). The frequency of a history of sexual or physical abuse was greater in the NES group (32.4%) than in the CPE controls (8.6%; p < 0.000). Severity of sexual but not physical abuse was significantly greater in the NES group relative to controls (p < 0.05). There was a trend for a closer relationship of the perpetrator of sexual abuse to the victim among the NES patients compared with CPE controls (p < 0.1). These results support the impression that childhood abuse is more common among patients with conversion NES than with epilepsy, and suggests that in some cases childhood abuse may be a contributory pathogenetic factor.     

Comparative genetics in the grasses

Genetic mapping of wheat, maize, and rice and other grass species with common DNA probes has revealed remarkable conservation of gene content and gene order over the 60 million years of radiation of Poaceae. The linear organization of genes in some nine different genomes differing in basic chromosome number from 5 to 12 and nuclear DNA amount from 400 to 6,000 Mb, can be described in terms of only 25 "rice linkage blocks." The extent to which this intergenomic colinearity is confounded at the micro level by gene duplication and micro-rearrangements is still an open question. Nevertheless, it is clear that the elucidation of the organization of the economically important grasses with larger genomes, such as maize (2n = 10, 4,500 Mb DNA), will, to a greater or lesser extent, be predicted from sequence analysis of smaller genomes such as rice, with only 400 Mb, which in turn may be greatly aided by knowledge of the entire sequence of Arabidopsis, which may be available as soon as the turn of the century. Comparative genetics will provide the key to unlock the genomic secrets of crop plants with bigger genomes than Homo sapiens.     

Differential aspects of conceptual processing in the Category Test and Wisconsin Card Sorting Test

Ninety-six veterans from neuropsychiatric wards were administered the Category Test (CT), Wisconsin Card Sorting Test (WCST), and a series of concept formation tests assessing attribute identification and rule learning. The CT and WCST shared only 30% common variance, and related to different facets of concept formation. The WCST was associated with attribute identification, which entails discrimination of relevant features, while the CT was more related to rule learning, which assesses the deduction of classification rules. The CT and WCST should not be regarded as similar measures of one construct such as "abstraction." Use of discrete scores from each test can help assess different aspects of concept formation.     

A link adaptation scheme optimized for wireless JPEG 2000 transmission over realistic MIMO systems

This paper proposes a Joint Source Channel Coding solution optimized for a wireless JPEG 2000 (JPWL ISO/IEC 15444-11) image transmission scheme over a MIMO channel. To ensure robustness of the transmission, channel diversity is exploited with a Closed-Loop MIMO-OFDM scheme. This relies on the Channel State Information (CSI) knowledge on the transmitter side, which allows the MIMO channel to be decomposed into several hierarchical SISO subchannels. In the proposed scheme, the JPWL codestream is divided into hierarchical quality layer passing through the SISO subchannels. With the CSI, a global and optimal method for adjusting all the system parameters of each SISO subchannel is provided. Accordingly, adaptive modulation, Unequal Error Protection (UEP), Unequal Power Allocation (UPA) and source coding rate is provided for each quality layers. The major strength of this work is to provide an optimal method that parameterizes several variables. These have an effect on the rate-distortion trade-off under bitrate, Quality of Service (QoS) and power constraints. Finally, the proposed work allows flexible and reactive coding of a JPWL codestream adapted to the instantaneous channel status. The performance of this technique is evaluated over a realistic time-varying MIMO channel provided by a 3D-ray tracing propagation model. A significant improvement in the quality of the image is demonstrated.     

Improved voltage tripler structure with symmetrical stacking chargepump

An improved voltage tripler with a symmetrical stacking charge pump is proposed. In this original voltage tripler, parasitic capacitances are pre-charged to reduce their influence, thus reducing the output voltage loss due to parasitic capacitances by a factor of 2