Classifying human operator functional state based on electrophysiological and performance measures and fuzzy clustering method

The human operator’s ability to perform their tasks can fluctuate over time. Because the cognitive demands of the task can also vary it is possible that the capabilities of the operator are not sufficient to satisfy the job demands. This can lead to serious errors when the operator is overwhelmed by the task demands. Psychophysiological measures, such as heart rate and brain activity, can be used to monitor operator cognitive workload. In this paper, the most influential psychophysiological measures are extracted to characterize Operator Functional State (OFS) in automated tasks under a complex form of human–automation interaction. The fuzzy c-mean (FCM) algorithm is used and tested for its OFS classification performance. The results obtained have shown the feasibility and effectiveness of the FCM algorithm as well as the utility of the selected input features for OFS classification. Besides being able to cope with nonlinearity and fuzzy uncertainty in the psychophysiological data it can provide information about the relative importance of the input features as well as the confidence estimate of the classification results. The OFS pattern classification method developed can be incorporated into an adaptive aiding system in order to enhance the overall performance of a large class of safety–critical human–machine cooperative systems.     

Temporal Coherence of Chlorophyll a during a Spring Phytoplankton Bloom in Xiangxi Bay of Three‐Gorges Reservoir,China

Algal bloom phenomenon was defined as “the rapid growth of one or more phytoplankton species which leads to a rapid increase in the biomass of phytoplankton”, yet most estimates of temporal coherence are based on yearly or monthly sampling frequencies and little is known of how synchrony varies among phytoplankton or of the causes of temporal coherence during spring algal bloom. In this study, data of chlorophyll a and related environmental parameters were weekly gathered at 15 sampling sites in Xiangxi Bay of Three‐Gorges Reservoir (TGR, China) to evaluate patterns of temporal coherence for phytoplankton during spring bloom and test if spatial heterogeneity of nutrient and inorganic suspended particles within a single ecosystem influences synchrony of spring phytoplankton dynamics. There is a clear spatial and temporal variation in chlorophyll a across Xiangxi Bay. The degree of temporal coherence for chlorophyll a between pairs of sites located in Xiangxi Bay ranged from –0.367 to 0.952 with mean and median values of 0.349 and 0.321, respectively. Low levels of temporal coherence were often detected among the three stretches of the bay (Down reach, middle reach and upper reach), while high levels of temporal coherence were often found within the same reach of the bay. The relative difference of DIN between pair sites was the strong predictor of temporal coherence for chlorophyll a in down and middle reach of the bay, while the relative difference in Anorganic Suspended Solids was the important factor regulating temporal coherence in middle and upper reach. Contrary to many studies, these results illustrate that, in a small geographic area (a single reservoir bay of approximately 25 km), spatial heterogeneity influence synchrony of phytoplankton dynamics during spring bloom and local processes may override the effects of regional processes or dispersal. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Synthesis of novel steroidal agonists,partial agonists,and antagonists for the glucocorticoid receptor

Adverse effects of glucocorticoids could be limited by developing new compounds that selectively modulate anti-inflammatory activity of the glucocorticoid receptor (GR). We have synthesized a novel series of steroidal GR ligands, including potent agonists, partial agonists and antagonists with a wide range of effects on inhibiting secretion of interleukin-6. Some of these new ligands were designed to directly impact conformational stability of helix-12, in the GR ligand-binding domain (LBD). These compounds modulated GR activity and glucocorticoid-induced gene expression in a manner that was inversely correlated to the degree of inflammatory response. In contrast, compounds designed to directly modulate LBD epitopes outside helix-12, led to dissociated levels of GR-mediated gene expression and inflammatory response. Therefore, these new series of compounds and their derivatives will be useful to dissect the ligand-dependent features of GR signaling specificity.     

Selenium-containing 15-mer peptides with high glutathione peroxidase-like activity

Glutathione peroxidase (GPX) is one of the most crucial antioxidant enzymes in a variety of organisms. Here we described a new strategy for generating a novel GPX mimic by combination of a phage-displayed random 15-mer peptide library followed by computer-aided rational design and chemical mutation. The novel GPX mimic is a homodimer consisting of a 15-mer selenopeptide with an appropriate catalytic center, a specific binding site for substrates, and high catalytic efficiency. Its steady state kinetics was also studied, and the values of k(cat)/K(m)(GSH) and k(cat)/ K(mH(2)O(2)) were found to be similar to that of native GPX and the highest among the existing GPX mimics. Moreover, the novel GPX mimic was confirmed to have a strong antioxidant ability to inhibit lipid peroxidation by measuring the content of malondialdehyde, cell viability, and lactate dehydrogenase activity. Importantly, the novel GPX mimic can penetrate into the cell membrane because of its small molecular size. These characteristics endue the novel mimic with potential perspective for pharmaceutical applications.     

Regulation of cystic fibrosis transmembrane regulator trafficking and protein expression by a Rho family small GTPase TC10

The cystic fibrosis transmembrane conductance regulator (CFTR)-interacting protein, CFTR-associated ligand (CAL) down-regulates total and cell surface CFTR by targeting CFTR for degradation in the lysosome. Here, we report that a Rho family small GTPase TC10 interacts with CAL. This interaction specifically up-regulates CFTR protein expression. Co-expression of the constitutively active form, TC10Q75L, increases total and cell surface CFTR in a dose-dependent fashion. Moreover, co-expression of the dominant-negative mutant TC10T31N causes a dose-dependent reduction in mature CFTR. The effect of TC10 is independent of the level of CFTR expression, because a similar effect was observed in a stable cell line that expresses one-tenth of CFTR. Co-expression of TC10Q75L did not have a similar effect on the expression of plasma membrane proteins such as Frizzled-3 and Pr-cadherin or cytosolic proteins such as tubulin and green fluorescent protein. TC10Q75L also did not have a similar effect on the vesicular stomatitis virus glycoprotein. Co-expression of constitutively active and dominant-negative forms of Cdc42 or RhoA did not affect CFTR expression in a manner similar to TC10, indicating that the effect of TC10 is unique within the Rho family. Metabolic pulse-chase experiments show that TC10 did not affect CFTR maturation, suggesting that it exerts its effects on the mature CFTR. Importantly, TC10Q75L reverses CAL-mediated CFTR degradation, suggesting that TC10Q75L inhibits CAL-mediated degradation of CFTR. TC10Q75L does not operate by reducing CAL protein expression or its ability to form dimers or interact with CFTR. Interestingly, the expression of TC10Q75L causes a dramatic redistribution of CAL from the juxtanuclear region to the plasma membrane where the two molecules overlap. These data suggest that TC10 regulates both total and plasma membrane CFTR expression by interacting with CAL. The GTP-bound form of TC10 directs the trafficking of CFTR from the juxtanuclear region to the secretory pathway toward the plasma membrane, away from CAL-mediated degradation of CFTR in the lysosome.     

Isolation and characterization of microsatellite loci in Pratt’s Leaf-nosed Bat (<Emphasis Type="Italic">Hipposideros pratti</Emphasis>) and cross-species amplification in closely related taxa

We developed nine microsatellite loci using an enriched library method from the genomic DNA of Pratt’s leaf-nosed bat (Hipposideros pratti). These loci were tested on 96 individuals sampled from Sichuan Province, China. The number of alleles per locus varied from 4 to 14. The expected and observed heterozygosity values ranged from 0.513 to 0.886 and from 0.375 to 0.966, respectively. Three microsatellite loci departed significantly from Hardy–Weinberg equilibrium (HWE). No linkage disequilibrium was found. These microsatellite loci will be used in studies of conservation genetics in this species.