Precise color tuning via hybrid light-emitting electrochemical cells

We report color-tunable light-emitting devices employing CdSe/ZnS quantum dots (QDs) blended into a polymer light-emitting electrochemical cell (LEC) architecture. This novel structure circumvents the charge-tunneling barrier of QDs to achieve bright, uniform, and highly voltage-independent electroluminescence, with nearly all emission generated by the QDs. By blending varying ratios of two QD materials that emit at different wavelengths, we demonstrate precise color control in a single layer device structure.     

A comparative study of changes in the microbiota of apple juice treated by high hydrostatic pressure (HHP) or high pressure homogenisation (HPH)

The objective of this study was to assess the effect of High Pressure Homogenisation (HPH) compared with High Hydrostatic Pressure (HHP) on the microbiological quality of raw apple juice during storage at ideal (4 °C) and abuse (12 °C) temperatures. In the case of HPH, only low numbers of micro-organisms were detected after treatment at 300 MPa (typically between 2 and 3 log.ml⁻¹). These were identified as Streptomyces spp., and numbers did not increase during storage of the juice for 35 days, irrespective of storage temperature. In the case of HHP, the total aerobic counts were also reduced significantly (p < 0.05) after treatment for 1 min at 500 and 600 MPa and the numbers did not increase significantly during storage at 4 °C. However, during storage at 12 °C the counts did increase significantly (p < 0.05) and by day 14 counts at 500 MPa were not significantly different from the control juice. This confirms that good temperature control is important if the full benefits of HHP treatment are to be realised.Frateuria aurantia dominated the microbiota of the HHP apple juice stored at 12 °C along with low levels of Bacillus and Streptomyces spp.The HPH and HHP juices both turned brown during storage indicating that neither treatment was sufficient to inactivate polyphenol oxidase. The enzyme is known to be pressure resistant and this discolouration was controlled by a heat treatment (70 °C for 1 min) used in commercial practice and given prior to HP treatment.     

Thalidomide and thalidomide analogs reduce HIV type 1 replication in human macrophages in vitro

Thalidomide is currently being evaluated for efficacy in alleviating some manifestations of HIV-1 infection. To determine whether thalidomide has any direct effects on HIV-1 infection, we investigated the effect of thalidomide and also of three structural analogs of thalidomide on HIV-1 replication in vitro in human monocyte-derived macrophages. The thalidomide analogs were previously shown to inhibit TNF-alpha production in vitro at much lower concentrations than thalidomide. In HIV-1-infected macrophages treated with thalidomide or thalidomide analogs, viral replication was reduced by 60 to 80% as determined by measuring viral RT activity in the culture supernatants. In all experiments the analogs inhibited HIV-1 replication more efficiently than did thalidomide. The drugs also reduced HIV-1 gag mRNA expression. Furthermore, the drugs caused a decrease in NF-kappaB-binding activity in nuclear extracts of HIV-1-infected macrophages. The role of NF-kappaB in the drug-induced inhibition of HIV-1 replication was confirmed using an NF-kappaB-defective mutant virus to infect macrophages.     

Portable, Fiber-Based, Diffuse Reflection Spectroscopy (DRS) Systems for Estimating Tissue Optical Properties

Steady-state diffuse reflection spectroscopy is a well-studied optical technique that can provide a noninvasive and quantitative method for characterizing the absorption and scattering properties of biological tissues. Here, we compare three fiber-based diffuse reflection spectroscopy systems that were assembled to create a light-weight, portable, and robust optical spectrometer that could be easily translated for repeated and reliable use in mobile settings. The three systems were built using a broadband light source and a compact, commercially available spectrograph. We tested two different light sources and two spectrographs (manufactured by two different vendors). The assembled systems were characterized by their signal-to-noise ratios, the source-intensity drifts, and detector linearity. We quantified the performance of these instruments in extracting optical properties from diffuse reflectance spectra in tissue-mimicking liquid phantoms with well-controlled optical absorption and scattering coefficients. We show that all assembled systems were able to extract the optical absorption and scattering properties with errors less than 10%, while providing greater than ten-fold decrease in footprint and cost (relative to a previously well-characterized and widely used commercial system). Finally, we demonstrate the use of these small systems to measure optical biomarkers in vivo in a small-animal model cancer therapy study. We show that optical measurements from the simple portable system provide estimates of tumor oxygen saturation similar to those detected using the commercial system in murine tumor models of head and neck cancer.     

The differential effect of child age on the illness intrusiveness–parent distress relationship in juvenile rheumatic disease.

Objective: Examine age-related patterns of association between parent-reported illness intrusiveness and parent distress in parents of youth with juvenile rheumatic diseases (JRDs). Study Design: Cross-sectional multiple regression analysis tested child age as a moderator in the illness intrusiveness–distress relationship. Participants: Fifty-two parents of children ages 9–17 diagnosed with JRD. Main Outcome Measures: The Illness Intrusiveness Scale—Parent Version and the Brief Symptom Inventory. Results: Parent-reported illness intrusiveness demonstrated a significant main effect on distress for all parents in the sample. This was qualified by an Illness Intrusiveness × Child Age interaction. Illness intrusiveness was found to be significantly related to distress among parents of older youth, but was only marginally related to distress for parents of younger children. Conclusions: Results are consistent with family life cycle development models of adjustment to childhood chronic illness. The clinical implications of the findings are also discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A simple method for maintaining relative positions of separate tissue elements during processing for electron microscopy.

Molten (328 K) 20% gelatin is used as a 'glue' to hold together separate tissue elements or tissue elements that may be separated when cutting small blocks of tissue for plastic embedding. Standard aldehyde and osmium fixation, dehydration and epoxy embedding are compatible with this as is semi-thin sectioning for light microscopy or thin sectioning for electron microscopy.     

Social utility Functions-part I: theory

The dominant approaches to utility-based multiagent decision theory rely on the premise of individual rationality-the doctrine that each individual is committed to achieving the best outcome for itself, regardless of the effect doing so has on others. This fundamentally asocial concept is the basis of conventional von Neumann-Morgenstern (vN-M) utilities but is inadequate to characterize truly cooperative artificial systems. Social utility functions differ from conventional vN-M utilities in that they are functions of multiple decision-maker preferences, rather than actions, and thus permit individuals to expand their spheres of interest beyond the self. A logical basis for coherent reasoning in multiagent environments must obey exactly the same desiderata as do multivariate probability functions. By taking a dual utilities approach (one to account for effectiveness and one to account for efficiency), a new game-theoretic structure, called satisficing games, provides a decision-making procedure that accounts for both individual and group interest and presents a framework for the design of sophisticated multiagent societies.     

Polymer Photovoltaic Devices Employing a Chemically Fixed p–i–n Junction

Polymer photovoltaic devices commonly suffer from low power conversion efficiencies despite the potential for much higher performance. Here we apply a recently reported system for creating a chemically fixed polymer p‐i‐n junction to polymer photovoltaic devices. Both single‐component and blended donor/acceptor devices are fabricated and tested. We study the devices during charging and find that the changes in light and dark current characteristics are consistent with the formation of a p‐i‐n junction in the active material. While the overall performance of these systems need improvement, the devices show promising open circuit voltages, suggesting the possibility for improving the state‐of‐the‐art in polymer photovoltaic techno logies with continued materials development.     

Determination of the transmembrane topology of yeast Sec61p, an essential component of the endoplasmic reticulum translocation complex

Sec61p is a highly conserved integral membrane protein that plays a role in the formation of a protein-conducting channel required for the translocation of polypeptides into, and across, the membrane of the endoplasmic reticulum. As a major step toward elucidating the structure of the endoplasmic reticulum translocation apparatus, we have determined the transmembrane topology of Sec61p using a combination of C-terminal reporter-domain fusions and the in situ digestion of specifically inserted factor Xa protease cleavage sites. Our data indicate the presence of 10 transmembrane domains, including several with surprisingly limited hydrophobicity. Furthermore, we provide evidence for complex intramolecular interactions in which these weakly hydrophobic domains require C-terminal sequences for their correct topogenesis. The incorporation of sequences with limited hydrophobicity into the bilayer may play a vital role in the formation of an aqueous membrane channel required for the translocation of hydrophilic polypeptide chains.     

The effect of long-term calcium supplementation on indices of iron, zinc and magnesium status in lactating Gambian women

The effect of long-term supplementation with CaCO3 on indices of Fe, Zn and Mg status was investigated in a randomized, double-blind intervention study of sixty lactating Gambian women. The supplement contained 1000 mg Ca and was consumed between meals 5 d/week, for 1 year starting 1.5 weeks postpartum. Compliance was 100%. Plasma ferritin concentration, plasma Zn concentration and urinary Mg output were measured before, during and after supplementation at 1.5, 13, 52 and 78 weeks postpartum. No significant differences in mineral status were observed at any time between women in the supplement and placebo groups. Analysis of the longitudinal data series showed that plasma ferritin and Mg excretion were characteristic of the individual (P < 0.001). Within individuals, ferritin concentration was higher at 1.5 weeks postpartum than later in lactation (P = 0.002). Plasma Zn concentration was lower at 1.5 weeks postpartum than at other times (P < 0.001), an effect which disappeared after albumin correction. Low plasma concentrations of ferritin and Zn indicated that the Gambian women were at high risk of Fe and Zn deficiency. Measurements of alpha 1-antichymotrypsin suggested that the results were not confounded by acute-phase responses. The results of the present study indicate that 1000 mg Ca as CaCO3 given between meals does not deleteriously affect plasma ferritin and Zn concentrations or urinary Mg excretion in women who are at risk of Fe and Zn deficiency.