Cerebral Folate Metabolism in Post-Mortem Alzheimer’s Disease Tissues: A Small Cohort Study

We investigated the cerebral folate system in post-mortem brains and matched cerebrospinal fluid (CSF) samples from subjects with definite Alzheimer’s disease (AD) (n = 21) and neuropathologically normal brains (n = 21) using immunohistochemistry, Western blot and dot blot. In AD the CSF showed a significant decrease in 10-formyl tetrahydrofolate dehydrogenase (FDH), a critical folate binding protein and enzyme in the CSF, as well as in the main folate transporter, folate receptor alpha (FRα) and folate. In tissue, we found a switch in the pathway of folate supply to the cerebral cortex in AD compared to neurologically normal brains. FRα switched from entry through FDH-positive astrocytes in normal, to entry through glial fibrillary acidic protein (GFAP)-positive astrocytes in the AD cortex. Moreover, this switch correlated with an apparent change in metabolic direction to hypermethylation of neurons in AD. Our data suggest that the reduction in FDH in CSF prohibits FRα-folate entry via FDH-positive astrocytes and promotes entry through the GFAP pathway directly to neurons for hypermethylation. This data may explain some of the cognitive decline not attributable to the loss of neurons alone and presents a target for potential treatment.     

Demand response in the UK's domestic sector

The purpose of this paper is to assess the current level of demand responsiveness among domestic loads. The paper first studies different load profiles of domestic consumers which are composed of power consumption of end-use appliances. Afterwards, it differentiates those loads which could become responsive and evaluates the aggregated effect of these loads and the margin which could be derived from them. The area which has been considered is a residential area; consists of results have been demonstrated on a real residential network in southwest of the UK; small residential area in city of Bath.     

恒定直流功率负荷下多晶硅微电阻电阻一时间特性测量

利用数字式恒定功率测试系统（ＤＣＰＳ）对多晶硅微电阻进行恒定直流功率负荷下电阻随时间变化特性的测量实验。用标准ＣＭＯＳ工艺和后续的腐蚀工艺制成悬浮结构多晶硅微电阻。测试结果表明,在恒定直流功率条件下工作的微电阻的稳定性由临界功率Ｐ_（ｃｒｉ）值决定,当负荷于电阻上的恒定直流功率Ｐ≤Ｐ_（ｃｒｉ）时,电阻值在负荷时间内保持常量;当Ｐ＞Ｐ_（ｃｒｉ）时,电阻值随时间增加而增加。临界功率值决定于流过电阻的电流密度、电阻结构尺寸以及环境温度。计算得到多晶硅薄膜的临界电流密度为 １０~５Ａ／ｃｍ~２数量级,不同于集成电路中的多晶硅薄膜的相应数值。     

Infants learn about objects from statistics and people.

In laboratory experiments, infants are sensitive to patterns of visual features that co-occur (e.g., Fiser & Aslin, 2002). Once infants learn the statistical regularities, however, what do they do with that knowledge? Moreover, which patterns do infants learn in the cluttered world outside of the laboratory? Across 4 experiments, we show that 9-month-olds use this sensitivity to make inferences about object properties. In Experiment 1, 9-month-old infants expected co-occurring visual features to remain fused (i.e., infants looked longer when co-occurring features split apart than when they stayed together). Forming such expectations can help identify integral object parts for object individuation, recognition, and categorization. In Experiment 2, we increased the task difficulty by presenting the test stimuli simultaneously with a different spatial layout from the familiarization trials to provide a more ecologically valid condition. Infants did not make similar inferences in this more distracting test condition. However, Experiment 3 showed that a social cue did allow inferences in this more difficult test condition, and Experiment 4 showed that social cues helped infants choose patterns among distractor patterns during learning as well as during test. These findings suggest that infants can use feature co-occurrence to learn about objects and that social cues shape such foundational learning in distraction-filled environments. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Ultraviolet Lamp Output Measurement: A Concise Derivation of the Keitz Equation

An equation relating the measured irradiance and the output power of a fluorescent lamp was derived by Keitz. The equation forms the basis for a new protocol that has been proposed for quantifying the total flux from an ultraviolet lamp. There has been confusion in the literature regarding the spatial distribution of flux from lamp emitters, which has led to emission models that are similar to the Keitz model but are incorrect. The Keitz equation is derived here from first principles in an effort to eliminate the confusion and present a correct method of calculating total flux.     

Development of open-cathode polymer electrolyte fuel cells using printed circuit board flow-field plates: Flow geometry characterisation

Open-cathode air-breathing fuel cells have the advantage of reduced system complexity and simplified operation, as oxygen is taken directly from ambient air without the need for blowers/compressors. In this study, printed circuit boards (PCBs) are used as flow-field plates. The use of PCBs offers the potential for significant cost reduction due to their well-established manufacturing processing and low materials cost. This study investigates the effect of varying the cathode geometry (parallel and circular) and opening ratios (43%, 53% and 63%) on fuel cell performance using polarisation curves, electrochemical impedance spectroscopy (EIS) and thermal imaging. The results obtained indicate that circular openings afford lower Ohmic resistance than parallel flow-field designs, which helps improve contact between the gas diffusion layer and flow-field plate. However, flow-field plates with circular openings suffer from greater mass transport limitation effects. Likewise, greater opening ratios offer better mass transport but increased Ohmic resistance as a result of the reduced area of lands/ribs. The thermal imaging results reveal lower temperature in the middle of the fuel cell due to “bowing” of the printed circuit board flow field plates which reduces the local current density. A trade-off between these factors results in a design with a maximum area specific power density of 250 mW cm⁻².     

Mesh generation and geometrical modelling of 3D woven composites with variable tow cross-sections

The modelling of 3D woven composites represents a key part in both material and component design. Current modelling techniques can struggle to mesh correctly accurate unit cell models and apply the complex but necessary periodic boundary conditions required, often with sacrifices made in idealisation of the weave architecture. An automated voxel meshing technique suitable for modelling failure in 3D woven composite unit cells has been developed, which is generic in nature and allows incorporation of architectural deformities within weaves, including tow rotations and misalignments. The model requires node points with only five independent variables to define the unit cell geometry. Application of a smoothing algorithm to the tow/matrix interface voxels produces a suitable surface for modelling tow/matrix debonding, leading to a more accurate representation of the stress field.