Fuel cells for road transportation purposes — yes or no?

The issues surrounding the application of fuel cells for road transportation are evaluated. The advantages and disadvantages of the candidate fuel-cell systems and the various fuels are discussed, together with the issue of whether the fuel should be converted directly in the fuel cell or should be first converted to hydrogen on-board the vehicle. Developments in competing vehicles technologies, namely, internal-combustion-engined vehicles (ICEVs), pure-battery vehicles (EVs) and ICE–battery hybrid vehicles (HEVs) are reviewed. Finally, the impact of the introduction of fuel-cell vehicles (FCVs) on industry, and in particular on the oil and automotive industries, is examined. For FCVs to compete successfully with conventional ICEVs, it is concluded that direct-conversion fuel cells — using probably hydrogen, but possibly methanol — are the only realistic contenders for road transportation applications.     

Contextual amplification of pubertal transition effects on deviant peer affiliation and externalizing behavior among African American children.

The effects of the pubertal transition on behavior problems and its interaction with family and neighborhood circumstances were examined with a sample of 867 African American children 10-12 years of age. Pubertal development status, pubertal timing, and primary caregivers' parenting behaviors were significantly related to affiliation with deviant peers and externalizing behaviors. Externalizing behavior among early-maturing children was associated positively with primary caregivers' use of harsh-inconsistent discipline and negatively with nurturant-involved parenting practices. Disadvantaged neighborhood conditions were significantly associated with deviant peer affiliation. The effect of pubertal transition varied according to family and neighborhood conditions: Early-maturing children living in disadvantaged neighborhoods were significantly more likely to affiliate with deviant peers. Early-maturing children with harsh and inconsistent parents were significantly more likely to have externalizing problems. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Parenting Behaviors and the Occurrence and Co-Occurrence of Depressive Symptoms and Conduct Problems Among African American Children.

The occurrence and co-occurrence of depressive symptoms and conduct problems were examined in the context of parenting behaviors in a community-based sample of 897 African American children and their primary caregivers using a multi-informant, longitudinal design. Parenting behaviors and clinical symptoms were assessed in 2 waves, when the children averaged 10.5 and 12.3 years of age. Parenting behaviors differed significantly according to a child's symptomatology; (a) that is, when a child exhibited no depressive or conduct problems, (b) depressive problems only, (c) conduct problems only, or (d) co-occurring depressive and conduct problems. When parenting behaviors were examined according to changes in children's symptom levels, children whose symptoms increased over time reported increases in hostility and harsh-inconsistent parenting and decreases in warmth and nurturant-involved parenting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

It's about timing and change: Pubertal transition effects on symptoms of major depression among African American youths.

Effects of early physical maturation and accelerated pubertal changes on symptoms of major depression were examined in 639 African American children. Three rival hypotheses, early timing, off-time, and stressful change, were tested using 2 waves of data (mean ages = 11 and 13 years). The pubertal effect operates differently according to children's gender and age. For girls, early maturation was consistently associated with elevated levels of depressive symptoms. For boys, early maturers manifested elevated levels of depression only at age 11, but these symptoms subsided by age 13. Boys who experienced accelerated pubertal growth over time displayed elevated symptom levels. Results support the early timing hypothesis for girls and the stressful change hypothesis for boys. Time at assessment is critical when examining boys' pubertal transition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Pretreatment of human platelets with plasmin inhibits responses to thrombin, but potentiates responses to low concentrations of aggregating agents, including the thrombin receptor activating peptide, SFLLRN

The distributional patterns of PLC isozymes within the kidney were investigated using spontaneously hypertensive rats (SHRs) and normotensive Wistar-Kyoto (WKY) rats at 4 and 12 weeks of age. PLC-beta 1, PLC-beta 3 and PLC-delta 1 quantified by Western blot analysis, were present in the highest concentrations in the inner medulla of rats at both 4 and 12 weeks of age. On the other hand, PLC-beta 4, PLC-gamma 1 and PLC-gamma 2 were distributed almost equally among the regions for the rats of both ages. When compared with WKY rats at 12 weeks of age, the amounts of PLC-beta 1, PLC-beta 3, PLC-gamma 1, PLC-gamma 2, and PLC-delta 1 in the inner medulla of SHRs were significantly lower, and the amount of PLC-delta 1 in the inner stripe of the outer medulla was also significantly lower. Even at the prehypertensive stage at 4 weeks of age, the inner medullary concentration of PLC-delta 1 was significantly lower in SHRs than WKY rats. These results suggest that PLC-delta 1 would play an important role in the development of hypertension.     

Factors associated with food workers working while experiencing vomiting or diarrhea

This study sought to determine the frequency with which food workers said they had worked while experiencing vomiting or diarrhea, and to identify restaurant and worker characteristics associated with this behavior. We conducted interviews with food workers (n=491) and their managers (n=387) in the nine states that participate in the Centers for Disease Control and Prevention's Environmental Health Specialists Network. Restaurant and worker characteristics associated with repeatedly working while experiencing vomiting or diarrhea were analyzed via multivariable regression. Fifty-eight (11.9%) workers said they had worked while suffering vomiting or diarrhea on two or more shifts in the previous year. Factors associated with workers having worked while experiencing vomiting or diarrhea were (i) high volume of meals served, (ii) lack of policies requiring workers to report illness to managers, (iii) lack of on-call workers, (iv) lack of manager experience, and (v) workers of the male gender. Our findings suggest that policies that encourage workers to tell managers when they are ill and that help mitigate pressures to work while ill could reduce the number of food workers who work while experiencing vomiting or diarrhea.     

Investigation of foreign particles in polycrystalline silicon using infrared microscopy

The presence of SiC and SiNO particles in as-grown polycrystalline silicon has been investigated using infrared (IR) microscopy. These foreign particles were also characterized using electron beam induced current measurements, and scanning electron microscopy together with energy dispersive spectrum analyses. These performance-degrading inclusions were found to be distributed throughout the bulk of the material and varied in size from several microns to about 20 μm. In addition to the observation of the foreign particles, the feasibility of using IR microscopy as a characterization tool was also demonstrated.     

Photovoltaic Devices: High‐Performance Organic Solar Cells with Spray Coated Hole‐Transport and Active Layers (Adv. Funct. Mater. 1/2011)

In this study, we report high performance organic solar cells with spray coated hole‐transport and active layers. With optimized ink formulations we are able to deposit films with controlled thickness and very low surface roughness (<10 nm). Specifically we deposit smooth and uniform 40 nm thick films of poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as well as films composed of a mixture of poly(3‐hexyl thiophene) (P3HT) and the C₆₀‐derivative (6,6)‐phenyl C61‐butyric acid methyl ester (PCBM) with thicknesses in the range 200–250 nm. To control film morphology, formation and thickness, the optimized inks incorporate two solvent systems in order to take advantage of surface tension gradients to create Marangoni flows that enhance the coverage of the substrate and reduce the roughness of the film. Notably, we achieve fill factors above 70% and attribute the improvement to an enhanced P3HT crystallization, which upon optimized post‐drying thermal annealing results in a favorable morphology. As a result, we could extend the thickness of the layer to several hundreds of nanometers without noticing a substantial decrease of the transport properties of the layer. By proper understanding of the spreading and drying dynamics of the inks we achieve spray coated devices with power conversion efficiency of 3.75%, with fill factor, short circuit current and open circuit voltage of 70%, 9.8 mA cm^?2 and 550 mV, respectively.     

Spatially resolved protein hydrogen exchange measured by matrix-assisted laser desorption ionization in-source decay

Mass spectrometry has become a powerful tool for measuring protein hydrogen exchange and thereby reveal the structural dynamics of proteins in solution. Here we describe the successful application of a matrix-assisted laser desorption ionization (MALDI) mass spectrometry approach based on in-source decay (ISD) to measure spatially resolved amide backbone hydrogen exchange. By irradiating deuterated protein molecules in a crystalline matrix with a high laser fluence, they undergo prompt fragmentation. Spatially resolved deuteration levels are readily obtained by mass analysis of consecutive fragment ions. MALDI ISD analysis of deuterated cytochrome c yielded an extensive series of c-fragment ions which originate from cleavage of nearly all N-C(α) bonds (Cys17 to Glu104) allowing for a detailed analysis of the deuterium content of the backbone amides. While hydrogen scrambling can be major concern when using mass spectrometric fragmentation to obtain detailed information on protein hydrogen exchange, we show that the level of hydrogen scrambling in our MALDI ISD measurements is negligible and that the known dynamic behavior of cytochrome c in solution is accurately reflected in the deuterium contents of the fragment ions. The developed method combines several attractive features from a practical point of view as it is simple to perform and it readily provides a detailed mapping of the dynamic structure of a protein in solution.     

Extensions to emergency vehicle location models

This paper is concerned with extending models for the maximal covering location problem in two ways. First, the usual 0–1 coverage definition is replaced by the probability of covering a demand within the target time. Second, once the locations are determined, the minimum number of vehicles at each location that satisfies the required performance levels is determined. Thus, the problem of identifying the optimal locations of a pre-specified number of emergency medical service stations is addressed by goal programming. The first goal is to locate these stations so that the maximum expected demand can be reached within a pre-specified target time. Then, the second goal is to ensure that any demand arising located within the service area of the station will find at least one vehicle, such as an ambulance, available. Erlang's loss formula is used to identify the arrival rates when it is necessary to add an ambulance in order to maintain the performance level for the availability of ambulances. The model developed has been used to evaluate locations for the Saudi Arabian Red Crescent Society, Riyadh City, Saudi Arabia.