126 research outputs found
Precipitation of amorphous ferromagnetic semiconductor phase in epitaxially grown Mn-doped Ge thin films
We investigated the origin of ferromagnetism in epitaxially grown Mn-doped Ge
thin films. Using low-temperature molecular beam epitaxy, Mn-doped Ge films
were successfully grown without precipitation of ferromagnetic Ge-Mn
intermetallic compounds, such as Mn5Ge3. Magnetic circular dichroism
measurements revealed that the epitaxially grown Mn-doped Ge films exhibited
clear ferromagnetic behavior, but the Zeeman splitting observed at the critical
points was not induced by the s,p-d exchange interactions. High-resolution
transmission electron microscopy and energy dispersive X-ray spectroscopy
analyses show phase separation of amorphous Ge1-xMnx clusters with high Mn
content from a Mn-free monocrystalline Ge matrix. Since amorphous Ge1-xMnx was
characterized as a homogeneous ferromagnetic semiconductor, the precipitation
of the amorphous Ge1-xMnx clusters is the origin of the ferromagnetic
semiconductor behavior of the epitaxially grown Mn-doped Ge films.Comment: 12pages, 4figure
Processing multiple image streams for real-time monitoring of parking lots
We present a system to detect parked vehicles in a typical parking complex using multiple streams of images captured through IP connected devices. Compared to traditional object detection techniques and machine learning methods, our approach is significantly faster in detection speed in the presence of multiple image streams. It is also capable of comparable accuracy when put to test against existing methods. And this is achieved without the need to train the system that machine learning methods require. Our approach uses a combination of psychological insights obtained from human detection and an algorithm replicating the outcomes of a SVM learner but without the noise that compromises accuracy in the normal learning process. Performance enhancements are made on the algorithm so that it operates well in the context of multiple image streams. The result is faster detection with comparable accuracy. Our experiments on images captured from a local test site shows very promising results for an implementation that is not only effective and low cost but also opens doors to new parking applications when combined with other technologies.<br /
Adhesion enhancement for electroless plating on mold compound for EMI shielding with industrial test compliance
In the manufacturing process, metal capping for
EMI shielding is done during the integrated circuit (IC)
assembly process, which hinders the attempt of reducing
the size of electronic device and also incurs higher cost of
assembly. Therefore direct deposition of metal on IC mold
compound is desirable. Conventional metal plating
techniques, however fail tape test. This paper studies the
condition of plating metal directly onto surface of mold
compound with the enhancement of novel non-etching
adhesion promoter CovaBond MRTM. By plating direct
onto mold compound, the shielding capping task can be
done in array form before the die saw process in IC
manufacturing (before IC assembly), which reduce the
thickness and dimension of chip and improves design
flexibility of circuit board as well as reduce the
manufacturing cost. The industrial test results in this
paper have proven the performance of the enhanced metal
plating technique
Can an incentive-based intervention increase physical activity and reduce sitting among adults? the ACHIEVE (Active Choices IncEntiVE) feasibility study
BackgroundDespite recent interest in the potential of incentivisation as a strategy for motivating healthier behaviors, little remains known about the effectiveness of incentives in promoting physical activity and reducing sedentary behavior, and improving associated health outcomes.This pre-post-test design study investigated the feasibility, appeal and effects of providing non-financial incentives for promoting increased physical activity, reduced sedentary time, and reduced body mass index (BMI) and blood pressure among inactive middle-aged adults.MethodsInactive men (n = 36) and women (n = 46) aged 40–65 years were recruited via a not-for-profit insurance fund and participated in a 4 month pre-post design intervention. Baseline and post-intervention data were collected on self-reported physical activity and sitting time (IPAQ-Long), BMI and blood pressure. Participants were encouraged to increase physical activity to 150 mins/week and reduce sedentary behavior by 150 mins/week in progressive increments. Incentives included clothing, recipe books, store gift vouchers, and a chance to win one of four Apple iPad Mini devices. The incentive component of the intervention was supported by an initial motivational interview and text messaging to encourage participants and provide strategies to increase physical activity and reduce sedentary behaviors.ResultsOnly two participants withdrew during the program, demonstrating the feasibility of recruiting and retaining inactive middle-aged participants. While two-thirds of the sample qualified for the easiest physical activity incentive (by demonstrating 100 mins physical activity/week or 100 mins reduced sitting time/week), only one third qualified for the most challenging incentive. Goals to reduce sitting appeared more challenging, with 43% of participants qualifying for the first incentive, but only 20% for the last incentive. More men than women qualified for most incentives. Mean leisure-time physical activity increased by 252 mins/week (leisure-time), with 65% of the sample achieving at least 150 mins/week; and sitting time decreased by 3.1 h/day (both p < 0.001) between baseline and follow-up. BMI, systolic and diastolic (men only) blood pressure all significantly decreased. Most participants (50–85%) reported finding the incentives and other program components helpful/motivating.ConclusionsAcknowledging the uncontrolled design, the large pre-post changes in behavioral and health-related outcomes suggest that the ACHIEVE incentives-based behavior change program represents a promising approach for promoting physical activity and reducing sitting, and should be tested in a randomized controlled trial.<br /
Quantitative analysis of an experimental white spot syndrome virus (WSSV) infection in Penaeus monodon Fabricius using competitive polymerase chain reaction
White spot syndrome virus (WSSV) has been a major pathogen of cultured Penaeus monodon Fabricius in Malaysia since 1994. As quantitative study on the replication of WSSV is in its infancy, competitive polymerase chain reaction (PCR) was used for quantitative study of an experimental WSSV infection per os in growout P. monodon. Gills, abdominal integument and abdominal muscle were selected for viral quantification. Infection was detectable as early as 14 h postinfection (h p.i.) in both gills and integument, but the infection in muscle was only detected at 24 h p.i. Gill tissue had the highest viral load, followed by integument and muscle. Typical viral growth curves were obtained for all organs with distinct phases of eclipse (0–24 h p.i.), logarithmic (24–48 h p.i.) and the plateau (48–120 h p.i.). Cumulative mortality rapidly increased from 48 h p.i. and reached 100% at the end of the plateau phase at 120 h p.i. Gross signs of white spots and reddish discoloration were also obvious in moribund individuals from the plateau phase. Based on the three phases of viral growth, WSSV infection was classified into light, moderate and heavy infection stages
Ternary copper(II)-polypyridyl enantiomers: aldol-type condensation, characterization, DNA-binding recognition, BSA-binding and anticancer property
Chiral enantiomers [Cu(phen)(l-threo)(H2O)]NO31 and [Cu(phen)(d-threo)(H2O)]NO32 (threo = threoninate) underwent aldol-type condensation with formaldehyde, with retention of chirality, to yield their respective enantiomeric ternary copper(ii) complexes, viz.l- and d-[Cu(phen)(5MeOCA)(H2O)]NO3·xH 2O (3 and 4; phen = 1,10-phenanthroline; 5MeOCA = 5-methyloxazolidine-4-carboxylate; x = 0-3) respectively. These chiral complexes were characterized by FTIR, elemental analysis, circular dichroism, UV-Visible spectroscopy, fluorescence spectroscopy (FL), molar conductivity measurement, ESI-MS and X-ray crystallography. Analysis of restriction enzyme inhibition by these four complexes revealed modulation of DNA binding selectivity by the type of ligand, ligand modification and chirality. Their interaction with bovine serum albumin was investigated by FL and electronic spectroscopy. With the aid of the crystal structure of BSA, spectroscopic evidence suggested their binding at the cavity containing Trp134 with numerous Tyr residues in subdomain IA. The products were more antiproliferative than cisplatin against cancer cell lines HK-1, MCF-7, HCT116, HSC-2 and C666-1 except HL-60, and were selective towards nasopharyngeal cancer HK-1 cells over normal NP69 cells of the same organ type
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Human fetal dendritic cells promote prenatal T-cell immune suppression through arginase-2.
During gestation the developing human fetus is exposed to a diverse range of potentially immune-stimulatory molecules including semi-allogeneic antigens from maternal cells, substances from ingested amniotic fluid, food antigens, and microbes. Yet the capacity of the fetal immune system, including antigen-presenting cells, to detect and respond to such stimuli remains unclear. In particular, dendritic cells, which are crucial for effective immunity and tolerance, remain poorly characterized in the developing fetus. Here we show that subsets of antigen-presenting cells can be identified in fetal tissues and are related to adult populations of antigen-presenting cells. Similar to adult dendritic cells, fetal dendritic cells migrate to lymph nodes and respond to toll-like receptor ligation; however, they differ markedly in their response to allogeneic antigens, strongly promoting regulatory T-cell induction and inhibiting T-cell tumour-necrosis factor-α production through arginase-2 activity. Our results reveal a previously unappreciated role of dendritic cells within the developing fetus and indicate that they mediate homeostatic immune-suppressive responses during gestation
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