Zinc absorption in Crohn's disease

Zinc deficiency is a potential complication of Crohn's disease and we have searched for evidence of this and assessed the possibility that malabsorption of zinc might be a cause. Serum zinc concentrations in 33 patients suffering from Crohn's disease were significantly lower than in 58 normal control subjects (9 . 18 +/- 2 . 3 mumol compared with 13 . 6 +/- 1 . 73 mumol, P < 0 . 0005). Serum zinc correlated well with serum albumin concentrations and the low serum zinc may simply reflect the low serum albumin. Thus its value as an indicator of zinc deficiency is poor. We studied zinc absorption in seven patients with Crohn's disease and compared it with the results obtained previously in five normal subjects using a new technique involving a short-lived isotope of zinc (69mZn). Plasma appearance curves, constructed after an oral dose of isotope, and disappearance curves, after an intravenous dose, were used in a deconvolution computer programme to calculate zinc absorption. Compared with normal subjects, zinc absorption was considerably impaired in patients with Crohn's disease (range 9--45%, compared with 38--75%). This abnormality is a potential cause of zinc deficiency in patients with Crohn's disease.     

Fibrillar polymer–polymer composites: morphology, properties and applications

Micro- or nano-fibrillar composites (MFCs or NFCs) are created by blending two homopolymers (virgin or recycled) with different melting temperatures such as polyethylene (PE) and poly(ethylene terephthalate) (PET), and processing the blend under certain thermo-mechanical conditions to create in situ fibrils of the polymer that has the higher-melting temperature. These resulting fibrillar composites have been reported to possess excellent mechanical properties and can have wide ranging applications with suitable processing under controlled conditions. However, the properties and applications very much depend on the morphology of created polymer fibrils and their thermal stability. The present paper develops an understanding of the mechanism of micro-/nano-fibril formation in PE/PET and polypropylene (PP)/PET blends by studying their morphology at various stages of extrusion and drawing. It is revealed that this subsequent mechanical processing stretches the polymer chains and creates fibrils of very high aspect ratios, thus resulting in superior mechanical performance of the composites compared to the raw blends. The study also identifies the primary mechanical properties of the main types of MFCs, as well as quantifying their enhanced resistance to oxygen permeability. Furthermore, the failure phenomena of these composites are studied via application of the modified Tsai–Hill criterion. In addition to their usage as input materials in different manufacturing processes, possible applications of these fibrillar composites in two different areas are also discussed, namely food packaging with controlled oxygen barrier properties and biomedical tissue scaffolding. Results indicate a significant scope for using these materials in both areas.     

Recent developments in pedestrian flow theory and research in Russia

Predtechenskii and Milinskii's seminal work [Predtechenskii VM, Milinskii AI. Planning for foot traffic flow in buildings. Revised and updated edition. Moscow: Stoiizdat; 1969] in relation to pedestrian flows is well known. However, analysis of the experimental results and observations obtained from this series of experimental studies revealed the inherent statistical non-homogeneity of pedestrian flow speeds [Kholshevnikov VV. The study of human flows and methodology of evacuation standardisation. Moscow: MIFS; 1999]. As such, the results of these individual experiments cannot be integrated to produce a valid general expression V=f(D) for each type of pedestrian flow path, where V is the flow velocity and D is the flow density. This paper presents further pedestrian flow research conducted in Russia post 1969.     

Microelectromechanical system-based adaptive space-variant imaging microspectrometer

An imaging spectrometer with adaptive space-variant spectral resolution is introduced to improve spectrometer data collection efficiency. Pixel-based dynamically selectable dispersion is achieved using microelectromechanical system (MEMS) mirrors to control the light path of each image point through the spectrometer. A compact (1 x 4 x 0.3 mm) planar-optics structure is demonstrated, allowing the tiling of multiple spectrometers in an array for large image formats. The prototype spectrometer covers a wavelength between 500 and 1000 nm with a spectral resolution that is dynamically adaptable for each pixel from 7.5 to 15 nm.     

SiC surface orientation and Si loss rate effects on epitaxial graphene

We have explored the properties of SiC-based epitaxial graphene grown in a cold wall UHV chamber. The effects of the SiC surface orientation and silicon loss rate were investigated by comparing the characteristics of each formed graphene. Graphene was grown by thermal decomposition on both the silicon (0001) and carbon (000-1) faces of on-axis semi-insulating 6H-SiC with a "face-down" and "face-up" orientations. The thermal gradient, in relation to the silicon flux from the surface, was towards the surface and away from the surface, respectively, in the two configurations. Raman results indicate the disorder characteristics represented by I_D/I_G down to < 0.02 in Si-face samples and < 0.05 in C-faces over the 1 cm² wafer surface grown at 1,450°C. AFM examination shows a better morphology in face-down surfaces. This study suggests that the optimum configuration slows the thermal decomposition and allows the graphene to form near the equilibrium. The Si-face-down orientation (in opposition to the temperature gradient) results in a better combination of low disorder ratio, I_D/I_G, and smooth surface morphology. Mobility of Si-face-down orientation has been measured as high as approximately 1,500 cm²/Vs at room temperature. Additionally, the field effect transistors have been fabricated on both Si-face-down and C-face-down showing an ambipolar behavior with more favorable electron conduction.     

The impact of the Workshop Activity for Gender Equity Simulation in the Academy (WAGES–Academic) in demonstrating cumulative effects of gender bias.

We report experimental evaluation of the Workshop Activity for Gender Equity Simulation in the Academy (WAGES–Academic), a brief, experiential simulation of the cumulative effects of unconscious bias in the academic workplace. We predicted that participants who played WAGES–Academic would demonstrate significantly increased knowledge and retention of gender equity issues in the academic workplace compared with participants in a control condition. Baseline information on general knowledge of workplace gender equity issues was obtained from 1,254 undergraduates. In the second phase, 144 were randomly assigned to complete either WAGES–Academic or a control task, and the immediate effects of the activities were measured. Participants were contacted 7–11 days later to complete an online measure of knowledge retention. Compared with a control condition, WAGES–Academic increased knowledge and retention. This effect occurred irrespective of prior level of sexist beliefs, participant gender, or whether the participant had been on the advantaged or disadvantaged team. Potential use and testing of WAGES–Academic with university faculty and administrators are discussed. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Comparisons among VOCs Measured in Three Types of U.S. Commercial Buildings with Different Occupant Densities

Abstract Volatile organic compounds (VOCs) have been simultaneously measured indoors and outdoors at 50 sparsely occupied telecommunications (Telco) offices, 9 variably occupied data centers and 11 densely occupied administrative (Admin) offices. Comparisons among the three building types, as well as within each of the building types, showed the influence of ventilation and sources. On average, the Telco and Admin facilities were better ventilated than the Data Centers, and the geometric mean of the I/O's for ∑VOC (sum of the concentrations of identified VOCs) at Telco (3.2) and Admin (5.3) facilities were lower than at Data Centers (8.6). Admin Offices had more and stronger sources than Telco Offices; when comparably ventilated facilities were compared, many VOCs had I/O ratios that were significantly larger at the Admin Offices. Furthermore, certain VOCs were detected in Admin but not Telco Offices. The influence of human occupancy on indoor VOCs was gauged by comparing sparsely and densely occupied buildings. Octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), n-dodecane (n-C12) through n-hexadecane (n-C16), limonene, and, to a lesser extent, tetrachloroethylene were all present in higher concentrations when there were more occupants (per unit area). Within this set of compounds, D5 was the best marker of occupant density.     

Giving patients bad news

Dating violence presents many challenges to pediatric health care providers. It spans an age range from early high school to early adult years. Prevalence of dating violence appears to be greater than for violence among married couples. In addition, both males and females appear to be at risk for perpetration and victimization. Therefore, physicians and other health care providers need to screen all adolescent and young adult patients for dating violence. Primary prevention at the community level is also an important task to stem the tide of dating violence.     

Effects of channel restabilization on habitat diversity,twentymile creek,mississippi

Twentymile Creek, a sand-bed stream draining a 450 km² catchment in northeast Mississippi, was channelized prior to 1910, in 1938, and in 1966. Straightening and enlargement in 1966 was followed by channel instability—rapid bed degradation (2-4 m) and cross-section enlargement by 1.4 to 2.7 times. Grade control structures (GCS) (weirs with stoneprotected stilling basins) and various types of streambank protection were constructed along the channel in the early 1980s to restore stability. Other investigators have suggested that habitat recovery in incised, channelized streams is facilitated by construction of GCS because they create stable scour holes and promote natural formation of a low-flow channel flanked by vegetated berms. Effects of restabilization of Twentymile Creek on aquatic habitats were assessed in four ways. The fraction of the bank line covered by woody vegetation was mapped from aerial photographs taken in 1981 and 1985; physical habitat (depth, velocity, substrate, and cover) and fishes were sampled at base flow; and the existence and size of a low-flow channel was ascertained from cross-section surveys taken in 1980 and 1989. Woody vegetation, physical aquatic habitat, and fishes were also sampled from Mubby-Chiwapa Creek, a similar-sized unstable channel with no GCS. Physical habitat variables and fishes were sampled concurrently at five stations on Twentymile Creek, and four stations on Mubby-Chiwapa. Four of the five Twentymile stations were either above or below a GCS. Bank-line woody vegetation cover increased 8 per cent between 1981 and 1985 along Twentymile Creek but was stable along Mubby-Chiwapa. Reaches above and below GCS were deeper with slower current velocities than elsewhere. Mean Shannon diversity indices based on physical data were similar for both streams, but were 58 per cent higher for stations immediately above and below GCS than for other stations. Since construction of the GCS and bank protection measures, longitudinal berms have formed within the enlarged Twentymile Creek channel, creating a low-flow channel. Low-flow channel capacity was equivalent to a mean daily discharge equalled or exceeded 30 per cent of the time, and was considerably lower than the effective discharge. Differences in aquatic habitat diversity among the stations sampled were primarily due to the scour holes below the GCS and the low-flow channel. Thirty-nine fish species were collected from Twentymile Creek, but only 22 from Mubby-Chiwapa. Fourteen species were collected exclusively at GCS. Principal component analyses of the abundance of the eight numerically dominant fish species indicated similar faunas at most stations, but Twentymile Creek GCS stations were faunistically distinct. Abundance of several of the numerically dominant species was positively influenced by greater depths and lower velocities found near Twentymile GCS. The mean fish diversity index for Twentymile Creek was 29 per cent higher than for Mubby-Chiwapa, and fish diversity was positively correlated with substrate diversity and mean depth.     

Effects of dopamine transporter and receptor polymorphisms on smoking cessation in a bupropion clinical trial.

This study examined the role of dopaminergic genes in prospective smoking cessation and response to bupropion treatment in a placebo-controlled clinical trial. Smokers of European ancestry (N=418) provided blood samples for genetic analysis and received either bupropion or placebo (10 weeks) plus counseling. Assessments included the dopamine D2 receptor (DRD2) genotype, dopamine transporter (SLC6A3) genotype, demographic factors, and nicotine dependence. Smoking status was verified at the end of treatment (EOT) and at 6-month follow-up. The results provided evidence for a significant DRD2 × SLC6A3 interaction effect on prolonged smoking abstinence and time to relapse at EOT, independent of treatment condition. Such effects were no longer significant at 6-month follow-up, however. These results provide the first evidence from a prospective clinical trial that genes that alter dopamine function may influence smoking cessation and relapse during the treatment phase. (PsycINFO Database Record (c) 2010 APA, all rights reserved)