Elucidation of the Burkholderia cenocepacia hopanoid biosynthesis pathway uncovers functions for conserved proteins in hopanoid-producing bacteria

Hopanoids are bacterial surrogates of eukaryotic membrane sterols and among earth's most abundant natural products. Their molecular fossils remain in sediments spanning more than a billion years. However, hopanoid metabolism and function are not fully understood. Burkholderia species are environmental opportunistic pathogens that produce hopanoids and also occupy diverse ecological niches. We investigated hopanoids biosynthesis in Burkholderia cenocepacia by deletion mutagenesis and structural characterization of the hopanoids produced by the mutants. The enzymes encoded by hpnH and hpnG were essential for production of all C35 extended hopanoids, including bacteriohopanetetrol (BHT), BHT glucosamine and BHT cyclitol ether. Deletion of hpnI resulted in BHT production, while ΔhpnJ produced only BHT glucosamine. Thus, HpnI is required for BHT glucosamine production while HpnJ is responsible for its conversion to the cyclitol ether. The ΔhpnH and ΔhpnG mutants could not grow under any stress condition tested, whereas ΔhpnI, ΔhpnJ and ΔhpnK displayed wild-type growth rates when exposed to detergent, but varying levels of sensitivity to low pH and polymyxin B. This study not only elucidates the biosynthetic pathway of hopanoids in B. cenocepacia, but also uncovers a biosynthetic role for the conserved proteins HpnI, HpnJ and HpnK in other hopanoid-producing bacteria.whereas ΔhpnI, ΔhpnJ and ΔhpnK displayed wild-type growth rates when exposed to detergent, but varying levels of sensitivity to low pH and polymyxin B. This study not only elucidates the biosynthetic pathway of hopanoids in B. cenocepacia, but also uncovers a biosynthetic role for the conserved proteins HpnI, HpnJ and HpnK in other hopanoid-producing bacteria.

The executive committee of the Greek Professional Association of Social Work in an age of austerity: examining its response

This paper explores the response by the Greek Association of Social Workers (SKLE) to Greece's current economic crisis. Socioeconomic conditions in Greece have deteriorated rapidly since the imposition of a Structural Adjustment Programme as a condition of the loan Troika provided to Greece to address its class-based public debt crisis. Interviews were conducted with SKLE Executive Committee members to examine SKLE's response in the context of newly raised inequalities. Research results show that SKLE recognised the negative consequences to both service users and its members. However, SKLE continues to reformulate its strategy mostly as a social partner. SKLE's previous strategy entailed amongst other things the analysis of policy proposals and participation in welfare related government committees. This strategy is no longer relevant because decision-making powers have been transferred to transnational bodies. This paper elaborates on these findings and discusses the barriers that prohibit SKLE from differentiation of its strategy. Although the research is country specific, it has implications for the broader global debate because professional associations must reformulate their strategies for better serving of both their constituents and the collective good based on the social justice mandate of the profession.

Efficient predictive demand response using laguerre functions

Predictive Demand Response (DR) algorithms allow schedulable loads in power systems to be shifted to off-peak times. However, the size of the optimisation problems associated with predictive DR can grow very large and so efficient implementations of algorithms are desirable. In this paper Laguerre functions are used to significantly reduce the size of the optimisation needed to implement predictive DR, thus significantly increasing the efficiency of the implementation. © 2013 IEEE.

Executive functioning deficits in young adult survivors of bronchopulmonary dysplasia

Purpose: To assess long-term impairments of executive functioning in adult survivors of bronchopulmonary dysplasia (BPD). 
Method: Participants were assessed on measures of executive functioning, health-related quality of life (HRQoL) and social functioning. Survivors of BPD (n = 63; 34 males; mean age 24.2 years) were compared with groups comprising preterm (without BPD) (<1500 g; n = 45) and full-term controls (n = 63). Analysis of variance was used to explore differences among groups for outcome measures. Multiple regression analyzes were performed to identify factors predictive of long-term outcomes. 
Results: Significantly more BPD adults, compared with preterm and term controls, showed deficits in executive functioning relating to problem solving (OR: 5.1, CI: 1.4–19.3), awareness of behavior (OR: 12.7, CI: 1.5–106.4) and organization of their environment (OR: 13.0, CI: 1.6–107.1). Birth weight, HRQoL and social functioning were predictive of deficits in executive functioning. 
Conclusions: This study represents the largest sample of survivors into adulthood of BPD and is the first to show that deficits in executive functioning persist. Children with BPD should be assessed to identify cognitive impairments and allow early intervention aimed at ameliorating their effects.

Solar phase functions of cometary nuclei

Relatively few measurements of the solar phase function of cometary nuclei exist, despite the importance of this parameter in determining accurate sizes and its use in modeling surface properties. We make use of robotic telescopes and servicemode observing to monitor cometary nuclei over months at a time, combining intensive observations at a single epoch with regular short light-curve segments to efficiently account for brightness changes due to both nucleus rotation and changing solar phase angle. We present our latest results on comets 8P/Tuttle, 14P/Wolf, 67P/Churyumov- Gerasimenko and 110P/Hartley 3.

A First Step Towards Cost Functions for Quantum-dot Cellular Automata Designs

Quantum-dot cellular automata (QCA) is potentially a very attractive alternative to CMOS for future digital designs. Circuit designs in QCA have been extensively studied. However, how to properly evaluate the QCA circuits has not been carefully considered. To date, metrics and area-delay cost functions directly mapped from CMOS technology have been used to compare QCA designs, which is inappropriate due to the differences between these two technologies. In this paper, several cost metrics specifically aimed at QCA circuits are studied. It is found that delay, the number of QCA logic gates, and the number and type of crossovers, are important metrics that should be considered when comparing QCA designs. A family of new cost functions for QCA circuits is proposed. As fundamental components in QCA computing arithmetic, QCA adders are reviewed and evaluated with the proposed cost functions. By taking the new cost metrics into account, previous best adders become unattractive and it has been shown that different optimization goals lead to different “best” adders.