Short-term memory scanning in schizophrenic young adults.

Used the Sternberg item-recognition procedure to investigate the process of short-term memory scanning and recognition of common English words in 16 schizophrenics, 16 nonschizophrenic psychiatric patients, and 16 normals (college students). The S was required to respond as quickly and accurately as possible to whether a probe word matched the word or words shown a few seconds earlier. Results show that the 3 groups' response latencies increased at approximately equal rates as the memory set size increased, but the overall response latencies of both patient groups were profoundly slower than normals. All 3 groups revealed a significant serial position effect and a logarithmic reaction time function for the positive probe. No single model of the scanning strategy appears to fit straight-forwardly to the present data. It is concluded that the schizophrenics' short-term memory scanning was intact, and their slowness in response is, therefore, to be understood in terms of some dysfunction in their stimulus encoding, response selection, and/or response execution. (26 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Affective encoding and consequent remembering in schizophrenic young adults.

Investigated whether schizophrenics' recall deficit can be ameliorated if appropriate encoding behaviors are experimentally induced, using 18 schizophrenics, 15 nonschizophrenic psychiatric patients, and 19 normals. In Session 1, the S was shown 50 words on a screen one at a time and rated them in terms of pleasantness-unpleasantness (orienting task); an unexpected free recall followed (incidental recall). In Session 2 given 1 wk later, the S was forewarned about the recall test prior to his engagement in the orienting task for another 50-word list; 4 free-recall trials followed (intentional recall). The recalls of the 3 groups were comparable in both sessions. The recall performance was also examined separately for the pleasant and unpleasant words, as rated by the Ss. All 3 groups tended to recall pleasant words more often than unpleasant words. It is, therefore, concluded that the schizophrenics' recall and pleasure deficits are probably remediable by means of attentional and encoding treatments. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Enrichment of excess 210Po in anoxic ponds

We have investigated the cycling of naturally occurring 210Po in waters from seasonally anoxic Pond B (South Carolina) and permanently anoxic Jellyfish Lake (Palau Islands, western Pacific Ocean). The maximum 210Po activity in Pond B was about 14 mBq L(-1) during summer. This activity was much higher than its parent 210Pb activity, indicating excess 210Po inputs from bottom sediments. The summertime excess 210Po activity was accompanied by increases in Fe and Mn, suggesting 210Po diffusion from bottom sediments under reducing conditions. Activity of 210Po was much lower underwinter oxic conditions, most likely a consequence of efficient coprecipitation with Fe and Mn oxides that occurs with destruction of Pond B stratification. In permanently anoxic Jellyfish Lake, the maximum activity of 210Po was 133 mBq L(-1), among the highest reported from any surface aqueous environment. A box model suggests that the release of only 2% of 210Po, produced from the 210Pb in the bottom sediments, would account for the observed excess. Our results suggest that 210Po can be naturally enriched in anoxic environments to a high level, perhaps in concert with the Fe and Mn redox cycles.     

Antioxidant activity and profiles of common fruits in Singapore

Thirty-eight types of fruits commonly consumed in Singapore were systematically analysed for their hydrophilic oxygen radical absorbance capacity (H-ORAC), total phenolic content (TPC), ascorbic acid (AA) and various lipophilic antioxidants. Antioxidant composition and concentration varied widely across different fruits. Many of the tropical fruits tested were high in antioxidants. Amongst all fruits tested, sapodilla (Manilkara zapota) had the highest H-ORAC and TPC whilst guava had the highest AA per gram fresh weight. Papaya, red watermelon and cantaloupe had the highest β-cryptoxanthin, lycopene and β-carotene per gram fresh weight, respectively. On the other hand, durian and mangosteen were high in tocopherols and tocotrienols, respectively. Based on consumption data, Chinese Singaporeans appear to have a higher intake of carotenoids and tocopherols rich fruits compared to the US population. As fruits are a rich source of diverse antioxidants, efforts to promote consumption of a variety of fruits should be continued for public health benefits.     

Antioxidant activity and profiles of common vegetables in Singapore

Sixty-six types of vegetables commonly consumed in Singapore were analysed for their hydrophilic oxygen radical absorbance capacity (H-ORAC), total phenolic content (TPC), ascorbic acid (AA) and various lipophilic antioxidants. A single batch analysis of each vegetable showed that antioxidant composition and concentration varied widely across different vegetables. The vegetables with intense colours typically have high H-ORAC, TPC, AA, and carotenoid contents. Vegetables unique to the Asian market such as matrimony vine (Lycium chinense Miller), coriander, Chinese kale, water spinach and red chilli were consistently ranked high in H-ORAC, TPC, carotenoids and vitamin E levels. Based on consumption data, Chinese Singaporeans appear to have a higher intake of lutein, zeaxanthin, β-carotene, and tocopherols compared to the US population. Overall findings suggest that dark green leafy and brightly-coloured vegetables tend to contain high antioxidants. Our data are useful reference and substantiate many public health agencies’ recommendation to consume more vegetables, particularly the dark green leafy and brightly-coloured varieties.     

Performance enhancement of mSCTP for vertical handover across heterogeneous wireless networks

In the mobile Stream Control Transmission Protocol (mSCTP) for vertical handover, a mobile user may suffer from performance degradation due to the problems of packet reordering and retransmission timeout and due to the packet loss during handover. To solve these problems, we propose a new scheme of handover retransmission for mSCTP handover, in which the correspondent node retransmits the outstanding data packets to the mobile node over the new primary path. From simulation results, it is shown that the proposed scheme can avoid the packet reordering and retransmission timeout problems during handover. Moreover, we can see that the proposed scheme can significantly improve throughput of mSCTP handover, compared with the existing schemes. Copyright © 2009 John Wiley & Sons, Ltd.     

Thin-film encapsulation of top-emission organic light-emitting devices with polyurea/Al2O3 hybrid multi-layers

We developed a room-temperature encapsulation process based on multi-stack of ultra thin Al₂O₃ and polyurea layers for top-emission organic light-emitting devices (TEOLEDs). Device structure, including a capping layer for refractive-index matching and a thick polyurea buffer layer, was optimized to enhance light extraction without distorting electroluminescence spectrum. The efficiency of a TEOLED encapsulated with 5 pairs of Al₂O₃(50 nm)/polyurea(20 nm) layers was better than that of a glass-encapsulated TEOLED, whereas their color coordinates were almost identical. Moreover, the half-decay lifetime of a TEOLED encapsulated with 5 pairs of Al₂O₃/polyurea layers was 86% of that of a glass-encapsulated TEOLED. Water vapor transition rate of 5 pairs of Al₂O₃(50 nm)/polyurea(20 nm) layers on PET film was measured as low as 5 × 10⁻⁴ g/m² day.     

Block copolymers containing pyridine moieties: Precise synthesis and applications

This review highlights the precise synthesis and application of various well-defined rod–coil and coil–coil block copolymers composed of poly(2-(or 4-)vinylpyridine) (P2VP or P4VP) block(s) with pyridine moieties. These polymers were synthesized by means of living anionic polymerization. Poly(hexyl isocyanate) (PHIC) was used as the rod-like segment, because hexyl isocyanate undergoes living anionic polymerization under carefully selected conditions. This review describes the syntheses of the block copolymers, polystyrene-b-P2VP, polystyrene-b-P4VP, polyisoprene-b-P2VP, P2VP-b-poly(methyl methacrylate), P2VP-b-poly(ethylene oxide), P2VP-b-poly(2-(N-carbazolyl)ethyl methacrylate), P2VP-b-PHIC, P2VP-b-PHIC-b-P2VP, and PHIC-b-P2VP-b-PHIC. The formation of self-organized nanostructured materials and molecular assemblies by such block copolymers and their possible applications are also described. These assemblies include monolayers, microphase-separated periodic-ordered nanostructures, micelles, polymer–metal complexes, nanoparticles, inorganic and metal layers, and nanoporous films with nanoparticles.     

Preparation of PVA/PAN bicomponent nanofiber via electrospinning and selective dissolution

Bicomponent polymer solutions were prepared from two immiscible polymers, poly(vinylalcohol) (PVA) and polyacrylonitrile (PAN), and then used to prepare films and electrospun fibers. The miscibility and the surface morphology of the bicomponent polymer systems were determined. There was a strong relationship between the diameter of the electrospun fibers and the blend ratio used. By applying selective dissolution, using solvents such as hot water, acetic acid, or N,N‐dimethylformamide, to the films and fibers, one polymer component was removed selectively without affecting the other component. This resulted in a decrease in the diameter of the electrospun fibers and the formation of grooves, pores, and craters on the fiber surface. The width of the grooves decreased as the bicomponent polymer content increased. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009