Enantioselective antiplatelet actions of nipecotamides

This investigation retrospectively examined changes in marital satisfaction following stroke. The relationship between such changes and other pertinent factors were also examined, including severity of aphasia, knowledge of aphasia, number of months after stroke, and length of the marriage. The subjects were 40 spouses of patients with aphasia grouped according to severity of the aphasia (mild, moderate, severe). Spouses completed two different measures of marital satisfaction--the Marital Satisfaction Scale (MSS) and the Marital Comparison Level Index (MCLI). These measures were completed in both a prestroke (retrospective reporting) and a poststroke format to allow for change to be assessed. In addition, a Knowledge of Aphasia questionnaire was completed by the normal spouses to evaluate their understanding of the disorder of aphasia. There was a significant difference between prestroke and poststroke scores on both the MSS and the MCLI, indicating a lower level of satisfaction following the stroke. The amount of change between prestroke and poststroke MSS and MCLI scores was not related to either number of months poststroke or number of years married. Although there was no relationship between changes in prestroke and poststroke scores on the MCLI and Knowledge of Aphasia scores, there was a significant correlation between changes in these scores on the MSS and Knowledge of Aphasia scores. Hence, the more knowledge spouses had regarding aphasia, the less the negative impact the stroke had on marital satisfaction, as measured by the MSS. Results are discussed in terms of the interdisciplinary treatment needs of aphasic patients and the implications for future investigations.     

Repair of extensive ionizing-radiation DNA damage at 95 degrees C in the hyperthermophilic archaeon Pyrococcus furiosus

We investigated the capacity of the hyperthermophile Pyrococcus furiosus for DNA repair by measuring survival at high levels of 60Co gamma-irradiation. The P. furiosus 2-Mb chromosome was fragmented into pieces ranging from 500 kb to shorter than 30 kb at a dose of 2,500 Gy and was fully restored upon incubation at 95 degrees C. We suggest that recombination repair could be an extremely active repair mechanism in P. furiosus and that it might be an important determinant of survival of hyperthermophiles at high temperatures.     

A noncompetitive peptide inhibitor of the nicotinic acetylcholine receptor from Conus purpurascens venom

A paralytic peptide, psi-conotoxin Piiie has been purified and characterized from Conus purpurascens venom. Electrophysiological studies indicate that the peptide inhibits the nicotinic acetylcholine receptor (nAChR). However, the peptide does not block the binding of alpha-bungarotoxin, a competitive nAChR antagonist. Thus, psi-conotoxin Piiie appears to inhibit the receptor at a site other than the acetylcholine-binding site. As ascertained by sequence analysis, mass spectrometry, and chemical synthesis, the peptide has the following covalent structure: HOOCCLYGKCRRYOGCSSASCCQR* (O = 4-trans hydroxyproline; * indicates an amidated C-terminus). The disulfide connectivity of the toxin is unrelated to the alpha- or the alphaA-conotoxins, the Conus peptide families that are competitive inhibitors of the nAChR, but shows homology to the mu-conotoxins (which are Na+ channel blockers).     

The strategy of edge wear prediction in CIM concept

A monitoring of tool wear in different cutting operations has been studied for many years. Special techniques have been used to detect a wear status basing upon cutting forces, acoustic emission, temperature, torque and power, vibration, noise and acceleration sensors. The adapting of a proper prediction method allows to solve problems of an automatic supervision in Computer Integrated Manufacturing systems. A task of the abrasive edge wear index prediction can be formulated as follows: disposing by the data collection of the edge wear status in a time period preceding the concerning the wear status in the successive time period embraced by the prediction method.     

The lattice dynamics of the Fe(tpa) (NCS)2 complex : light-induced excited spin state trapping effect

A light-induced excited spin state trapping (LIESST) experiment for a thermal gradual spin crossover complex, Fetris (2-pyridylmethyl) amine(NCS)2 or Fe(tpa) (NCS)2, was attempted for the first time. The high spin (HS) state after light inducement stayed metastable over a period of days without relaxation at 10 K. Intersystem relaxation from a high to a low spin (LS) complex occurred at 50 K after bleaching at 10 K. Investigation of the Mossbauer spectra of the LIESST and relaxation experiment indicated that the Debye–Waller factor was a correlation parameter of the HS fraction and that the co-operative effect played a role in the relaxation process for such a solid compound. This revised version was published online in November 2006 with corrections to the Cover Date.     

Body odour preferences in men and women: do they aim for specific MHC combinations or simply heterozygosity?

The major histocompatibility complex (MHC) is an immunologically important group of genes that appears to be under natural as well as sexual selection. Several hypotheses suggest that certain MHC-allele combinations (usually heterozygous ones) are superior under selective pressure by pathogens. This could influence mate choice in a way that preferences function to create MHC-heterozygous offspring, or that they function to create specific allele combinations that are beneficial under the current environmental conditions through their complementary or epistatic effects. To test these hypotheses, we asked 121 men and women to score the odours of six T-shirts, worn by two women and four men. Their scorings of pleasantness correlated negatively with the degree of MHC similarity between smeller and T-shirt-wearer in men and women who were not using the contraceptive pill (but not in Pill-users). Depending on the T-shirt-wearer, the amount of variance in the scorings of odour pleasantness that was explained by the degree of MHC similarity (r2) varied between nearly 0 and 23%. There was no apparent effect of gender in this correlation: the highest r2 was actually reached with one of the male odours sniffed by male smellers. Men and women who were reminded of their own mate/ex-mate when sniffing a T-shirt had significantly fewer MHC-alleles in common with this T-shirt-wearer than expected by chance. This suggests that the MHC or linked genes influence human mate choice. We found no significant effect when we tested for an influence of the MHC on odour preferences after the degree of similarity between T-shirt-wearer and smeller was statistically controlled for. This suggests that in our study populations the MHC influences body odour preferences mainly, if not exclusively, by the degree of similarity or dissimilarity. The observed preferences would increase heterozygosity in the progeny. They do not seem to aim for more specific MHC combinations.     

Automatic tuning of decentralized PID controllers for MIMO processes

An automatic tuning algorithm for decentralized PID control in multiple-input multiple-output (MIMO) plants is presented. This algorithm generalizes the authors' recent auto-tuner for two-input two-output systems to any number of inputs and outputs. The algorithm consists of two stages. In the first, the desired critical point, which consists of the critical gains of all the loops and a critical frequency, is identified. The auto-tuner identifies the desired critical point with almost no a priori information about the process. During the identification phase all controllers are replaced by relays, thus generating limit cycles with the same period in all loops. It is shown that each limit cycle corresponds to a single critical point of the process. By varying the relays parameters different points can be determined. The auto-tuner contains a procedure which converges rapidly to the desired critical point while maintaining the amplitudes of the process variables as well as of the manipulated variables within prespecified ranges. In the second stage, the data of the desired critical point is used to tune the PID controllers by the Ziegler-Nichols rules or their modifications. This paper focuses on the first stage. The steady-state process gains, which are required for the appropriate choice of the desired critical point, are determined by the auto-tuner in closed-loop fashion simultaneously with the identification of the critical point. The identification of the process gains is achieved at no extra plant time. Based upon a large number of simulated cases, the proposed auto-tuner seems to be efficient and robust. The paper discusses the underlying principles of the auto-tuner and its properties and capabilities are demonstrated via examples.     

In Situ ceramic particle-reinforced aluminum matrix composites fabricated by reaction pressing in the TiO2 (Ti)-Al-B (B2O3) systems

Particulate TiB₂ reinforced aluminum-based metal matrix composites (MMCs) were successfully fabricated by means of the reaction processing method. TiB₂ particulates were formed in situ through the reaction of Ti and B in Ti-Al-B, TiO₂ and B in TiO₂-Al-B, and TiO₂ and B₂O₃ in TiO₂-Al-B₂O₃ systems. The results showed that in situ TiB₂ particulates formed in the Ti-Al-B system had a size of 5 μm and they exhibited block and rodlike structures. Moreover, coarse Al₃Ti blocks several tens of micrometers in size were also formed simultaneously. On the other hand, equiaxed Al₂O₃ and TiB₂ particulates with a size of less than 2 μm were formed in situ in the TiO₂-Al-B and TiO₂-Al-B₂O₃ systems. The Al₃Ti phase was completely eliminated in the TiO₂-Al-B system with increasing B content. Tensile tests revealed that the Al₂O₃ · TiB₂/Al composite fabricated from the TiO₂-Al-B system exhibits excellent mechanical properties. The yield strength of the Al₂O₃ · TiB₂/Al composite appeared to increase with increasing TiB₂ content. The yield strength of the Al₂O₃ · TiB₂/Al composite could be further increased by introducing CuO into the TiO₂-Al-B system. Such an increment in mechanical strength arose from the strengthening effect caused by the Al₂Cu precipitates. The incorporation of CuO had no effect on the in situ reaction process of the TiO₂-Al-B system. Finally, the effect of SiC addition on the microstructure and mechanical properties of the composites fabricated from the TiO₂-Al-B and TiO₂-Al-B-CuO systems was also investigated.     

A biased percolation model for the analysis of electronic-device degradation

The biased percolation model is proposed for investigating device degradation and failure associated with the generation of defects due to local Joule heating. The degradation processes of a thin conducting or semiconducting film is monitored by a set of relevant indicators, such as: the evolution of damage pattern, the current distribution, the film resistance and its fluctuations, the defect concentration, the film lifetime, etc. The conductor-insulator (CI) and conductor-superconductor (CS) like degradation processes are considered. The results can be used to propose non-destructive indicators to test the reliability of samples and to interpret the corresponding experiments.