Prenatally elevated physiological arousal interferes with perceptual learning in bobwhite quail (Colinus virginianus) embryos.

Neonatal studies suggest elevated arousal can negatively influence perceptual and cognitive processes during early development. The authors explored this issue during the prenatal period by pharmacologically elevating physiological arousal in bobwhite quail (Colinus virginianus) embryos during exposure to a maternal call, then assessing preference for the familiar call following hatching. Embryos receiving norepinephrine showed a prenatal elevation in heart rate and failed to demonstrate a preference for the familiar call following hatching. Embryos not receiving norepinephrine showed no elevation in heart rate and demonstrated a preference for the familiar call. These results indicate elevated arousal can interfere with perceptual learning during the prenatal period and provide additional evidence for an optimal window of arousal necessary to foster species-typical perceptual functioning during early development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

连铸板坯中心线偏析的预测

从生产经验和文献可知,结晶过程中产生的凝固收缩会导致中心线偏析,很多情况下,在热轧产品的中心也会发现结晶过程中产生的微细缩孔。从这方面讲,板坯凝固过程中形成缩孔簇的尺寸大小,以及形成这种缩孔的条件是首要的,在全面分析统计数据的基础上,对此进行了讨论,得出一个重要结论:当固液比率达到一定的值后,在此部位的铸坯中心只有糊状物,实际上没有更多的液体可以补充。建立了数学模型,用于计算板坯中心部位的流动速度和方向以及预测的疏松。计算表明,在给定的成分和冷却条件下,中心线偏析主要受支承辊的设置、形变和偏心度的影响,同时支承辊之间铸坯的鼓肚也是重要影响因素之一。     

Lipopeptide Nanoparticles: Development of Vaccines against Hookworm Parasite

Necator americanus (hookworm) infects over half a billion people worldwide. Anthelminthic drugs are commonly used to treat the infection; however, vaccination is a more favorable strategy to combat this parasite. We designed new B‐cell peptide epitopes based on the aspartic protease of N. americanus (Na‐APR‐1). The peptides were conjugated to self‐adjuvanting lipid core peptide (LCP) systems via stepwise solid‐phase peptide synthesis (SPPS) and copper catalyst azide–alkyne cycloaddition (CuAAC) reactions. The LCP vaccine candidates were able to self‐assemble into nanoparticles, were administered to mice without the use of additional adjuvant, and generated antibodies that recognized the parent epitope. However, only one LCP derivative was able to produce a high titer of antibodies specific to Na‐APR‐1; circular dichroism analyses of this compound showed a β‐sheet conformation for the incorporated epitope. This study provides important insight in epitope and delivery system design for the development of a vaccine against hookworm infections.     

Survival characteristics of Salmonella enterica serovar Newport in the dairy farm environment

Multi-drug resistant (MDR) Salmonella enterica serovar Newport (S. Newport) has established a reservoir in dairy cattle. Infected herds suffer significant mortality in both adult and young animals, posing a considerable economic loss to producers. Land application of manure from infected animals may further spread the pathogen into the agroecosystem, causing public health concerns. Previous work by our group demonstrated that the organism persisted in manure and manured soil for 6 to 10 mo under laboratory conditions. In the present study, we determined the survival characteristics of MDR S. Newport in a dairy lagoon, compost pile, and soil of a grass field under natural conditions using environmental sentinel chambers with an initial concentration of S. Newport around 7 log₁₀ per gram. In the static compost pile at 64°C, S. Newport was eliminated within 18 h. In the dairy effluent lagoon, the pathogen survived for >137 d, whereas in the field soil, the organisms persisted for over 276 d. The survival of MDR S. Newport in both the lagoon and field soil followed a pattern of (1) an increase or plateau for a few days, (2) log-linear decline for 6 to 13 wk, and (3) a long tailing phase at low and variable concentration for 4 to 9 mo. Log reduction times (days required for 90% decrease in concentration) based on the log-linear decline phase were 7 d in the lagoon and 14 to 20 d in the soil. Conditions leading to faster inactivation during the initial phase do not necessarily translate into a quicker elimination of the pathogen. Regression models of the log-linear phase may be inaccurate for estimating complete pathogen elimination.     

Investigation of surface roughness on etched glass surfaces

Roughening the surface of solar cells is a common practice within the photovoltaic industry as it reduces reflectance, and thus enhances the performance of devices. In this work the relationship between reflectance characterized by the haze parameter, surface roughness and optical properties was investigated. To achieve this goal, model samples were prepared by hydrofluoric acid etching of glass for various times and measured by optical microscopy, spectroscopic ellipsometry, scanning electron microscopy, and atomic force microscopy. Our investigation showed that the surface reflectance was decreased not only by the roughening of the surface but also by the modification of the depth profile and lowering of the refractive index of the surface domain of the samples.     

Patterns of relatedness, depressive symptomatology, and perceived competence in maltreated children.

An attachment theory framework is applied toward understanding the emergence of depressive symptomatology and lower perceived competence in maltreated and nonmaltreated children. Hypotheses that maltreated children with nonoptimal patterns of relatedness evidence elevated depressive symptomatology and lower competence, whereas nonmaltreated children with optimal or adequate patterns of relatedness exhibit the least depressive symptomatology and higher competence, were confirmed. Additionally, differentiations between maltreated children with and without optimal or adequate patterns of relatedness emerged, suggesting that relatedness may mitigate against the adverse effects of maltreatment. Moreover, sexually abused children with confused patterns of relatedness evidenced clinically significant depressive symptomatology. Results are discussed with regard to mechanisms that contribute to adaptation or maladaptation in children with negative caregiving histories (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

GraphClus,a MATLAB program for cluster analysis using graph theory

Cluster analysis is used in numerous scientific disciplines. A method of cluster analysis based on graph theory is discussed and a MATLAB? code for its implementation is presented. The algorithm is based on the number of variables that are similar between samples. By changing the similarity criterion in a stepwise fashion, a hierarchical group structure develops, and can be displayed by a dendrogram. Three indexes describe the homogeneity of a given variable in a group, the heterogeneity of that variable between two groups, and the usefulness of that variable in distinguishing two groups. The algorithm is applied to both a synthetic dataset and a set of trace element analyses of lavas from Mount Etna in order to compare GraphClus to other cluster analysis algorithms.     

Size effects in glass fragment identification by micro-x-ray fluorescence analysis

Energy-dispersive x-ray fluorescence (EDXRF) analysis with a lateral resolution of 300 μm has been used in scanning electron microscopy to carry out model experiments for the identification of small glass fragments. Small sample dimensions can produce size effects which cause intensity changes in the EDXRF spectra as compared with bulk specimen spectra. These effects can be analysed by means of the inelastically scattered Mo Kα source line as long as the x-ray spot size is smaller than the specimen dimension.