3,291 research outputs found

    Advances in research on personalized venous thromboembolism risk assessment tools

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    AbstractThis paper describes the definition of venous thromboembolism and introduces to personalized venous thromboembolism risk assessment tools overseas. Thoughts are given on the development, amendment, application and validation of these tools. The paper provides a reference for building personalized venous thromboembolism risk assessment tools in China

    The development and confirmatory factor analysis of the Service-Learning Reflection Scale for undergraduates

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    The purpose of this study is to develop and to examine the construct validity of the service-learning reflection scale for undergraduates based on Kolb\u27s learning theory. The research aims to: (1) recognize undergraduates\u27 levels of reflection for service-learning; (2) let undergraduates understand their learning styles; (3) evaluate the effect of service-learning for the instructors. We used the Likert\u27s style to make the scales. There are 33 items in the initial scale divided into four subscales inclusive of the concrete experience (CE), the reflection observation (RO), the abstract conceptualization (AC), and the active experience (AE). For the very first time, we invite four experts to evaluate all the items to proceed three times Delphi technique process. We adopt the item analysis, exploratory factor analysis and reliability analysis via 326 participants in the pretest. Cronbach\u27s alpha reliability coefficients of the four subscales are from .80 to .87, and that of the total scale was .95. The whole explained variance was 60.16%. In this study, we make use of the stratified sampling, 1,251 undergraduates, to analyze the construct validity by the confirmatory factor analysis. The model index such as GFI, AGFI, NFI, RFI, IFI and CFI are above .90, RMSEA and RMR are below .05, as well as PGFI and PNFI are above .50. In addition, the structural equation modeling analysis indicates measurement weights, measurement intercepts, structural covariance matrixes and measurement residuals of male/female and general/technical undergraduates groups are no significant differences. Moreover, the Cronbach\u27s alpha values of the four subscales are from .85 to .86, and that of the total scale is .95. The results show that the CFA and reliability analysis confirm the theoretical structure as well

    Critical Neurons: optimized visual recognition in a neuronal network

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    In the past few decades, there have been intense debates whether the brain operates at a critical state. To verify the criticality hypothesis in the neuronal networks is challenging and the accumulating experimental and theoretical results remain controversial at this point. Here we simulate how visual information of a nature image is processed by the finite Kinouchi-Copelli neuronal network, extracting the trends of the mutual information (how sensible the neuronal network is), the dynamical range (how sensitive the network responds to external stimuli) and the statistical fluctuations (how criticality is defined in conventional statistical physics). It is rather remarkable that the optimized state for visual recognition, although close to, does not coincide with the critical state where the statistical fluctuations reach the maximum. Different images and/or network sizes of course lead to differences in details but the trend of the information optimization remains the same. Our findings pave the first step to investigate how the information processing is optimized in different neuronal networks and suggest that the criticality hypothesis may not be necessary to explain why a neuronal network can process information smartly.Comment: 11 pages, 4 figures in the main text and 3 figures in the Supplementary Informatio

    Vectors for multi-color bimolecular fluorescence complementation to investigate protein-protein interactions in living plant cells

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    <p>Abstract</p> <p>Background</p> <p>The investigation of protein-protein interactions is important for characterizing protein function. Bimolecular fluorescence complementation (BiFC) has recently gained interest as a relatively easy and inexpensive method to visualize protein-protein interactions in living cells. BiFC uses "split YFP" tags on proteins to detect interactions: If the tagged proteins interact, they may bring the two split fluorophore components together such that they can fold and reconstitute fluorescence. The sites of interaction can be monitored using epifluorescence or confocal microscopy. However, "conventional" BiFC can investigate interactions only between two proteins at a time. There are instances when one may wish to offer a particular "bait" protein to several "prey" proteins simultaneously. Preferential interaction of the bait protein with one of the prey proteins, or different sites of interaction between the bait protein and multiple prey proteins, may thus be observed.</p> <p>Results</p> <p>We have constructed a series of gene expression vectors, based upon the pSAT series of vectors, to facilitate the practice of multi-color BiFC. The bait protein is tagged with the C-terminal portion of CFP (cCFP), and prey proteins are tagged with the N-terminal portions of either Venus (nVenus) or Cerulean (nCerulean). Interaction of cCFP-tagged proteins with nVenus-tagged proteins generates yellow fluorescence, whereas interaction of cCFP-tagged proteins with nCerulean-tagged proteins generates blue fluorescence. Additional expression of mCherry indicates transfected cells and sub-cellular structures. Using this system, we have determined in both tobacco BY-2 protoplasts and in onion epidermal cells that <it>Agrobacterium </it>VirE2 protein interacts with the <it>Arabidopsis </it>nuclear transport adapter protein importin α-1 in the cytoplasm, whereas interaction of VirE2 with a different importin α isoform, importin α-4, occurs predominantly in the nucleus.</p> <p>Conclusion</p> <p>Multi-color BiFC is a useful technique to determine interactions simultaneously between a given" bait" protein and multiple "prey" proteins in living plant cells. The vectors we have constructed and tested will facilitate the study of protein-protein interactions in many different plant systems.</p

    Aplikasi Image Thresholding Untuk Segmentasi Objek

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    Salah satu operasi di dalam analisis citra adalah segmentasi citra, yaitu memisahkan objek dari latar belakangnya atau dari objek lain yang tidak menjadi perhatian. Metode sementasi yang sederhana adalah dengan operasi pengambangan (thresholding). Operasi pengambangan menghasilkan citra biner, yang dalam hal ini objek yang diacu di-set berwarna putih sedangkan latar belakangnya di-set berwarna hitam (atau sebaliknya bergantung kasusnya). Makalah ini mempresentasikan penggunaan operasi pengambangan untuk melakukan segmentasi objek. Eksperimen dilakukan dengan menggunakan kakas MATLAB. Hasil eksperimen memperlihatkan bahwa pemilihan nilai ambang (threshold) yang tepat sangat menentukan keberhasilan segmentasi

    Numerical investigation of the structure of a silicon six-wafer micro-combustor under the effect of hydrogen/air ratio

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    Research reports indicate that sufficiently high equivalence ratio of the hydrogen/air mixture leads to the upstream burning in the recirculation jacket, possibly damaging the micro- combustor due to the high wall temperature. This work investigates the influences of the equivalence ratio of the mixture on the structure of a micro-combustor device. Numerical simulation approaches focused on the structural design of the micro-combustor with the flame burning in the recirculation jacket. Combustion characteristics of the combustor were first analysed based on 2D computational Fluid Dynamics (CFD), and then thermo-mechanical analysis on the combustor was carried out by means of 3D Finite Element Analysis (FEA) method. The results showed that the most dangerous locations where the critical failure could possibly occur lay at the burning areas in the recirculation jacket due to the poor bonding, the high temperature and the residual stress. The results of this study can be used for the design and improvement of the micro-combustors

    Can the Functional Movement Screen Method Identify Previously Injured Wushu Athletes?

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    The functional movement screen (FMS) is commonly used to evaluate sports injury risks, but no study has been reported for Wushu athletes. The aim of this study was to identify optimal FMS cut-off points for previously injured Wushu athletes and to examine the associations with other possible factors. In this study, a total of 84 Chinese Wushu athletes (15.1 ± 4.5 years old, 51% male) with a minimum of two years of professional training background in either Taiji, Changquan, or Nanquan were assessed by the FMS. Video recordings were used to confirm the scoring criteria, and previous injuries were assessed based on face-to-face interviews. An optimal cut-off of the FMS score was investigated by receiver operating characteristic curves with sensitivity and specificity. We found that FMS score of less than 16 (sensitivity = 80%, specificity = 56%) was related to an increased occurrence of injuries (odds ratio = 5.096, 95%CI: 1.679–15.465) for the current study sample. The training type and training levels were related with FMS scores. More than half of the athletes (58%) had FMS asymmetry and 21% of athletes reported pain while performing the FMS protocol. Future prospective studies are recommended to use FMS with cut-off of 16 points in Wushu athletes

    Analytic functions and complex integration

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    This paper presents some basic theory of analytic function. The class of analytic functions is formed by the complex functions of a complex variable which possess a derivative wherever the function is defined. Beginning with the definition of the derivative, the necessary and sufficient conditions for a function to be analytic at a point are developed. In order to prove that the derivative of an analytic function is itself analytic, the line integrals are defined. The exact differential and its relation to line integrals are discussed. Then Cauchy's theorem is stated. Since the proof of Cauchy's theorem is so complicated and can be found in most texts on complex variable, it is skipped. Lastly Cauchy's integral formula is developed. The formula is an ideal tool for the study of local properties of analytic functions. Particularly it helps to show that an analytic function has derivatives of all orders, which are then analytic. With this result, the converse of Cauchy's theorem, known as Morera's theorem, can be proved. Last, the paper discusses Liouville's theorem concerning entire function

    Two variants on T2DM susceptible gene HHEX are associated with CRC risk in a Chinese population

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    Increasing amounts of evidence has demonstrated that T2DM (Type 2 Diabetes Mellitus) patients have increased susceptibility to CRC (colorectal cancer). As HHEX is a recognized susceptibility gene in T2DM, this work was focused on two SNPs in HHEX, rs1111875 and rs7923837, to study their association with CRC. T2DM patients without CRC (T2DM-only, n=300), T2DM with CRC (T2DM/CRC, n=135), cancer-free controls (Control, n=570), and CRC without T2DM (CRC-only, n=642) cases were enrolled. DNA samples were extracted from the peripheral blood leukocytes of the patients and sequenced by direct sequencing. The χ(2) test was used to compare categorical data. We found that in T2DM patients, rs1111875 but not the rs7923837 in HHEX gene was associated with the occurrence of CRC (p= 0.006). for rs1111875, TC/CC patients had an increased risk of CRC (p=0.019, OR=1.592, 95%CI=1.046-2.423). Moreover, our results also indicated that the two variants of HEEX gene could be risk factors for CRC in general population, independent on T2DM (p< 0.001 for rs1111875, p=0.001 for rs7923837). For rs1111875, increased risk of CRC was observed in TC or TC/CC than CC individuals (p<0.001, OR= 1.780, 95%CI= 1.385-2.287; p<0.001, OR= 1.695, 95%CI= 1.335-2.152). For rs7923837, increased CRC risk was observed in AG, GG, and AG/GG than AA individuals (p< 0.001, OR= 1.520, 95%CI= 1.200-1.924; p=0.036, OR= 1.739, 95%CI= 0.989-3.058; p< 0.001, OR= 1.540, 95%CI= 1.225-1.936). This finding highlights the potentially functional alteration with HHEX rs1111875 and rs7923837 polymorphisms may increase CRC susceptibility. Risk effects and the functional impact of these polymorphisms need further validation
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