Low-temperature noninjection approach to homogeneously-alloyed PbSe(x)S(1-x) colloidal nanocrystals for photovoltaic applications

Homogeneously alloyed PbSe(x)S(1-x) nanocrystals (NCs) with their excitonic absorption peaks in wavelength shorter than 1200 nm were developed for photovoltaic (PV) applications. Schottky-type solar cells fabricated with our PbSe?.?S?.? NCs as their active materials reached a high power conversion efficiency (PCE) of 3.44%, with an open circuit voltage (V(oc)) of 0.49 V, short circuit photocurrent (J(sc)) of 13.09 mA/cm2, and fill factor (FF) of 0.54 under Air Mass 1.5 global (AM 1.5G) irradiation of 100 mW/cm2. The syntheses of the small-sized colloidal PbSe(x)S(1-x) NCs were carried out at low temperature (60 °C) with long growth periods (such as 45 min) via a one-pot noninjection-based approach in 1-octadecene (ODE), featuring high reaction yield, high product quality, and high synthetic reproducibility. This low-temperature approach employed Pb(oleate)? as a Pb precursor and air-stable low-cost thioacetamide (TAA) as a S source instead of air-sensitive high-cost bis(trimethylsilyl)sulfide ((TMS)?S), with n-tributylphosphine selenide (TBPSe) as a Se precursor instead of n-trioctylphosphine selenide (TOPSe). The reactivity difference of TOPSe made from commercial TOP 90% and TBPSe made from commercial TBP 97% and TBP 99% was addressed with in situ observation of the temporal evolution of NC absorption and with 31P nuclear magnetic resonance (NMR). Furthermore, the addition of a strong reducing/nucleation agent diphenylphosphine (DPP) promoted the reactivity of the Pb precursor through the formation of a Pb-P complex, which is much more reactive than Pb(oleate)?. Thus, the reactivity of TBPSe was increased more than that of TAA. The larger the DPP-to-Pb feed molar ratio, the more the Pb-P complex, the higher the Se amount in the resulting homogeneously alloyed PbSe(x)S(1-x) NCs. Therefore, the use of DPP allowed reactivity match of the Se and S precursors and led to sizable nucleation at low temperature so that long growth periods became feasible. The present study brings insight into the formation mechanism of monomers, nucleation/growth of colloidal composition-tunable NCs, and materials design and synthesis for next-generation low-cost and high-efficiency solar cells.     

Waste to resource: Converting paper mill wastewater to bioplastic

In this study we investigated the feasibility of producing polyhydroxyalkanoate (PHA) by microbial enrichments on paper mill wastewater. The complete process includes (1) paper mill wastewater acidogenic fermentation in a simple batch process, (2) enrichment of a PHA-producing microbial community in a selector operated in sequencing batch mode with feast-famine regime, (3) Cellular PHA content maximization of the enrichment in an accumulator in fed-batch mode. The selective pressure required to establish a PHA-producing microbial enrichment, as derived from our previous research on synthetic medium, was validated using an agro-industrial waste stream in this study. The microbial enrichment obtained could accumulate maximum up to 77% PHA of cell dry weight within 5 h, which is currently the best result obtained on real agro-industrial waste streams, especially in terms of biomass specific efficiency. Biomass in this enrichment included both Plasticicumulans acidivorans, which was the main PHA producer, and a flanking population, which exhibited limited PHA-producing capacity. The fraction of P. acidivorans in the biomass was largely dependent on the fraction of volatile fatty acids in the total soluble COD in the wastewater after acidification. Based on this observation, one simple equation was proposed for predicting the PHA storage capacity of the enrichment. Moreover, some crucial bottlenecks that may impede the successful scaling-up of the process are discussed.     

Support behavior and relationship satisfaction in couples dealing with diabetes: Main and moderating effects.

This study examined associations between support behavior, i.e. active engagement and protective buffering, and relationship satisfaction in both patients with diabetes and their partners. Active engagement refers to supportive behavior characterized by involving one's partner in discussions, asking how the other feels, and problem solving strategies. Protective buffering refers to less supportive behavior characterized by denying fears and worries, and by pretending everything is fine. Furthermore, we examined whether there were interactive effects of these two support behaviors on patients' and partners' relationship satisfaction. At baseline (T1), 205 couples rated to which degree they received active engagement and protective buffering from their partners, and completed a measure of relationship satisfaction. At three follow-up assessments, couples were asked to fill out the same measures. Using dyadic data analytic approaches, we found relationship satisfaction to be positively associated with active engagement, and negatively with protective buffering, in both patients and partners. Moreover, we found a moderating effect, in that the negative association between protective buffering and relationship satisfaction was only present when levels of active engagement were relatively low. Again, these results were found for patients as well as their partners. We were able to replicate the T1 results at the other three assessment points. Our findings illustrate the need to consider adequate and less adequate support behaviors simultaneously, and to study the effects on both patients and partners. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Persuasive strategies in mobile insomnia therapy: alignment, adaptation, and motivational support

The aim of this paper is to reflect on the underlying principles of insomnia therapy in relation to the use of mobile technology and to present a starting point in the design of computerized insomnia treatment. Three general persuasive strategies are presented for the design of a virtual mobile coach that functions as a first intervention for insomnia treatment in a stepped care context. The presented strategies are based on general principles and methods from cognitive behavior therapy and communication theory. In this paper, it is assumed that the motivation to perform the therapy exercises significantly can be improved by individual tailoring to the characteristics and the circumstances of the user. Two of the presented strategies aim at tailoring the intervention: alignment and adaptation; the third strategy, motivational support, aims at the coach’s communicative activities to take away motivational blockades. Given the characteristics of the insomnia treatment, it is concluded that mobile and ubiquitous systems are promising monitoring and delivery devices in a first intervention, provided that the information is reliable and that obtrusiveness is minimized.     

Does marriage protect older people from distress? The role of equity and recency of bereavement.

The association between marital status and distress was examined in a largely neglected group, namely older people (65 and older; N = 1,649). In this 2-wave study, married persons were less distressed than single persons, but perceived equity within the marriage and recency of bereavement qualified these findings. Married persons who felt inequitably treated were more distressed than persons who had always been single. Married persons reported less distress than recently (= 2 years ago) widowed persons, but only equitably treated married persons reported less distress than persons widowed for more than 2 years. Increased distress between the 2 waves occurred in recently widowed persons, and there was a decrease in distress in persons who were widowed shortly before the 1st wave. No gender effects were found. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The synthesis of poly(butylene terephthalate) from terephthalic acid,part I: The influence of terephthalic acid on the tetrahydrofuran formation

An in depth study is performed on the origin of and influences on the formation of tetrahydrofuran (THF) during the first stage of the terephthalic acid (TPA) based synthesis of poly(butylene terephthalate) (PBT). Although many improvements on the synthesis process of PBT have been reported in literature to suppress this undesired side reaction, only few studies reported on the actual mechanism of the THF formation, which is not completely understood. Low molecular weight compounds have been used to model the side reactions occurring during the polymerization reaction. It could be concluded that, in contrast to previous reportage, only the THF formation from the monomer, 1,4‐butanediol, is directly influenced by the use of TPA as a starting material for the production of PBT. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

The tenacious goal pursuit and flexible goal adjustment scales: A validation study.

The flexible goal adjustment (FLEX) and tenacious goal pursuit (TEN) scales are used regularly in aging research. The current study examined their validity in a sample of 517 women (30–75 years) in multiple ways. Overall, the findings show that the scales do not clearly distinguish between FLEX and TEN. The direction in which the items were formulated was just as important as what was being measured. Moreover, face validity of the inversely phrased items in particular appeared to be weak. On the basis of these findings, the authors recommend a revision of the concept definitions as well as of the items. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The linkage of (1–3)-β-glucan to chitin during cell wall assembly in Saccharomyces cerevisiae

Pulse-chase experiments with [¹⁴C]glucose demonstrated that in the cell wall of wild-type Saccharomyces cerevisiae alkali-soluble (1–3)-β-glucan serves as a precursor for alkali-insoluble (1–3)-β-glucan. The following observations support the notion that the insolubilization of the glucan is caused by linkage to chitin: (i) degradation of chitin by chitinase completely dissolved the glucan, and (ii) disruption of the gene for chitin synthase 3 prevented the formation of alkali-insoluble glucan. These cells, unable to form a glucan–chitin complex, were highly vulnerable to hypo-osmotic shock indicating that the linkage of the two polymers significantly contributes to the mechanical strength of the cell wall. Conversion of alkali-soluble glucan into alkali-insoluble glucan occurred both early and late during budding and also in the ts-mutant cdc24-1 in the absence of bud formation.     

Cognitive marital therapy: The process of change.

Responds to comments made by N. Epstein and D. H. Baucom (see record 1989-16434-001) concerning the present authors' (see record 1989-16433-001) study of communication skills training and cognitive therapy for distressed couples. The reliable assessment of cognitions in outcome studies is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)