2,074 research outputs found

    Schwoebel barriers on Si(111) steps and kinks

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    Motivated by our previous work using the Stillinger-Weber potential, which shows that the [211\overline{2}11] step on 1×\times1 reconstructed Si(111) has a Schwoebel barrier of 0.61±\pm0.07 eV, we calculate here the same barrier corresponding to two types of kinks on this step - one with rebonding between upper and lower terrace atoms (type B) and the other without (type A). From the binding energy of an adatom, without additional relaxation of other atoms, we find that the Schwoebel barrier must be less than 0.39 eV (0.62 eV) for the kink of type A (type B). From the true adatom binding energy we determine the Schwoebel barrier to be 0.15±\pm0.07eV (0.50±\pm0.07 eV). The reduction of the Schwoebel barrier due to the presence of rebonding along the step edge or kink site is argued to be a robust feature. However, as the true binding energy plots show discontinuities due to significant movement of atoms at the kink site, we speculate on the possibility of multi-atom processes having smaller Schwoebel barriers.Comment: Manuscript in revtex twocolumn format (7pgs - which includes 14 postscript files). Submitted to the The Journal of Vacuum Science and Technology (Proceedings of the Physics and Chemistry of Semi- conductor Interfaces - 23 (1996)

    Shallow Triple Stream Three-dimensional CNN (STSTNet) for Micro-expression Recognition

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    In the recent year, state-of-the-art for facial micro-expression recognition have been significantly advanced by deep neural networks. The robustness of deep learning has yielded promising performance beyond that of traditional handcrafted approaches. Most works in literature emphasized on increasing the depth of networks and employing highly complex objective functions to learn more features. In this paper, we design a Shallow Triple Stream Three-dimensional CNN (STSTNet) that is computationally light whilst capable of extracting discriminative high level features and details of micro-expressions. The network learns from three optical flow features (i.e., optical strain, horizontal and vertical optical flow fields) computed based on the onset and apex frames of each video. Our experimental results demonstrate the effectiveness of the proposed STSTNet, which obtained an unweighted average recall rate of 0.7605 and unweighted F1-score of 0.7353 on the composite database consisting of 442 samples from the SMIC, CASME II and SAMM databases.Comment: 5 pages, 1 figure, Accepted and published in IEEE FG 201

    Cystic benign prostatic hyperplasia in a dog

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    Old intact male dogs are often predisposed to benign prostatic hyperplasia. Both hypertrophy and hyperplasia of prostate gland occur due to hormonal influences. Clinical signs such as haematuria, stranguria and tenesmus are often associated with benign prostatic hyperplasia. A seven year-old local breed intact male dog was presented with a primary complaint of haematuria and stranguria. Diagnostic work-up conducted inclusive of complete blood count, serum biochemistry, urinalysis, abdominal radiograph, cystourethrography and abdominal ultrasonography. The dog was diagnosed with cystic benign prostatic hyperplasia. Prostatic omentalisation and castration were performed in this case

    Determination of folate content in commonly consumed Malaysian foods

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    Currently, data concerning the content of naturally occurring dietary folate in Malaysian foods is scarce. The aim of this study was to determine the folate content of vegetables, fruits, legumes and cereals that were commonly consumed among Malaysians. The total folate content of 156 samples (51 vegetables, 33 fruits, 22 legumes and legume products, and 50 cereals and cereal products) available in Malaysia was determined by microbiological assay using Lactobacillus casei (L. casei) after trienzyme treatment with protease, α-amylase and folate conjugase (from rat serum). An internal quality control system was used throughout the study by analyzing CRM 121 (wholemeal flour) and CRM 485 (lyophilized mixed vegetables); percent recovery (as mean ± SD) of 97 ± 2.0 and 101 ± 4.0 was obtained. The range of folate content in vegetables, fruits, legumes and cereals were 1-11 μg/100 g and 1-31on the basis of fresh weight and 1-31 μg/100 g and 2-156 μg/100 g on the basis of dry weight, respectively. This study has shown that some of these underutilized vegetables and fruits are good sources of folate and could fulfill the recommended dietary intake of total folate

    Investigating diet as the source of tetrodotoxin in Pleurobranchaea maculata

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    The origin of tetrodotoxin (TTX) is highly debated; researchers have postulated either an endogenous or exogenous source with the host accumulating TTX symbiotically or via food chain transmission. The aim of this study was to determine whether the grey side-gilled sea slug (Pleurobranchaea maculata) could obtain TTX from a dietary source, and to attempt to identify this source through environmental surveys. Eighteen non-toxic P. maculata were maintained in aquariums and twelve were fed a TTX-containing diet. Three P. maculata were harvested after 1 h, 24 h, 17 days and 39 days and TTX concentrations in their stomach, gonad, mantle and remaining tissue/fluids determined using liquid chromatography-mass spectrometry. Tetrodotoxin was detected in all organs/tissue after 1 h with an average uptake of 32%. This decreased throughout the experiment (21%, 15% and 9%, respectively). Benthic surveys at sites with dense populations of toxic P. maculata detected very low or no TTX in other organisms. This study demonstrates that P. maculata can accumulate TTX through their diet. However, based on the absence of an identifiable TTX source in the environment, in concert with the extremely high TTX concentrations and short life spans of P. maculata, it is unlikely to be the sole TTX source for this species

    Effects of Solder Temperature on Pin Through-Hole during Wave Soldering: Thermal-Fluid Structure Interaction Analysis

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    An efficient simulation technique was proposed to examine the thermal-fluid structure interaction in the effects of solder temperature on pin through-hole during wave soldering. This study investigated the capillary flow behavior as well as the displacement, temperature distribution, and von Mises stress of a pin passed through a solder material. A single pin throughhole connector mounted on a printed circuit board (PCB) was simulated using a 3D model solved by FLUENT. The ABAQUS solver was employed to analyze the pin structure at solder temperatures of 456.15 K (183∘C)

    The scenario of two-dimensional instabilities of the cylinder wake under EHD forcing: A linear stability analysis

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    We propose to study the stability properties of an air flow wake forced by a dielectric barrier discharge (DBD) actuator, which is a type of electrohydrodynamic (EHD) actuator. These actuators add momentum to the flow around a cylinder in regions close to the wall and, in our case, are symmetrically disposed near the boundary layer separation point. Since the forcing frequencies, typical of DBD, are much higher than the natural shedding frequency of the flow, we will be considering the forcing actuation as stationary. In the first part, the flow around a circular cylinder modified by EHD actuators will be experimentally studied by means of particle image velocimetry (PIV). In the second part, the EHD actuators have been numerically implemented as a boundary condition on the cylinder surface. Using this boundary condition, the computationally obtained base flow is then compared with the experimental one in order to relate the control parameters from both methodologies. After validating the obtained agreement, we study the Hopf bifurcation that appears once the flow starts the vortex shedding through experimental and computational approaches. For the base flow derived from experimentally obtained snapshots, we monitor the evolution of the velocity amplitude oscillations. As to the computationally obtained base flow, its stability is analyzed by solving a global eigenvalue problem obtained from the linearized Navier–Stokes equations. Finally, the critical parameters obtained from both approaches are compared

    Development and preliminary validation of socio-cultural influences on body image scale for Malaysian female adolescents

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    The present study aimed to develop and validate comprehensive multi-dimensional sociocultural (parental, peers, media) influence on body image scale for Malaysian female adolescents. A total of 328 female adolescents from a secondary school in Kuantan district, Pahang, Malaysiacompleted a self-administered questionnaire, which encompassed a multiple measure of sociocultural influence, Body Dissatisfaction and Body Importance subscales of Body Image Questionnaire (McCabe & Ricciardelli, 2001), and Body Change Inventory (Ricciardelli & McCabe, 2002). Through factor analysis, the three major components (parental, peers, media) of the sociocultural influence scale were found to consist of multi-dimensional constructs. Particularly, five dimensions were identified for the parental influence subscale: 1) parental teasing on weight, 2) parental encouragement on increasing muscle and weight, 3) parental social support, 4) parental preoccupation with thinness and dieting behaviour, and 5) parental feedback on body change behaviour; the peer influence subscale comprised four dimensions including 1) peer social support, 2) peer preoccupation with thinness and dieting behaviour, 3) peer teasing on weight, and 4) peer encouragement on increasing muscle and weight; and three dimensions were identified in the media influence subscale, which included 1) media encouragement on reducing weight, 2) media modeling on weight reducing behaviour, and 3) media encouragement on increasing muscle and weight. As for construct validity, there were positive correlations between the composite score of the subscales and body dissatisfaction, body importance, strategies to decrease body size and strategies to increase body size and muscle size. In short, the present study has developed a sociocultural (parental, peer, media) influences on body image scale with construct validity and good internal consistency for Malaysian female adolescents. The scale can be used to assess the various dimensions of socio-cultural influences and will be useful to determine the etiology, prevention and treatment of negative body image and its related problems for Malaysian female adolescents

    MTHFR C677T polymorphism, homocysteine and B vitamins status in a sample of Chinese and Malay subjects in Universiti Putra Malaysia.

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    INTRODUCTION: Methylenetetrahydrofolate reductase (MTHFR) C677T is involved in folate and homocysteine metabolism. Disruption in the activity of this enzyme will alter their levels in the body. METHODOLOGY: This study assessed MTHFR C677T polymorphism and its relationship with serum homocysteine and B-vitamins levels in a sample of Chinese and Malays subjects in UPM, Serdang. One hundred subjects were randomly selected from among the university population. Folate, vitamin B12, B6, and homocysteine levels were determined using MBA, ECLIA, and HPLC, respectively. PCR coupled with HinfI digestion was used for detection of MTHFR C677T polymorphism. RESULTS: The frequency of T allele was higher in the Chinese subjects (0.40) compared to the Malay (0.14). Folate, vitamin B12 and B6 levels were highest in the wild genotype in both ethnic groups. Subjects with heterozygous and homozygous genotype showed the highest homocysteine levels. The serum folate and homocysteine were mainly affected by homozygous genotype. CONCLUSION: MTHFR C677T polymorphism plays an important role in influencing the folate and homocysteine metabolism

    Nutrient Composition of Selected Cooked and Processed Snack Foods

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    Nutrient composition of 27 cooked snack foods and 19 processed snacks was determined. The cooked foods were mostly cereal based, made from wheat flour, rice or rice flour, and almost all of them were traditional Malaysian kuih or dishes. The processed snacks studied were chocolate, cereal, tuber, fish and prawn products. The levels of 19 nutrients were tabulated, expressed as per 100 g edible portion. Selected nutrients in each serving or packet of the foods were also presented. The paper is intended as a contribution to the knowledge on nutrient composition of local snack foods, for which information is still greatly lacking. The number of foods studied is only a fraction of the total number available. More work in this area will have to be carried out, to meet the increasing demand for such data
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