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Search Results: 1 - 10 of 34806 matches for " Pei Sun Loh "
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The Distribution of Sedimentary Organic Matter and Implication of Its Transfer from Changjiang Estuary to Hangzhou Bay, China  [PDF]
Fanglu Xu, Zhongqiang Ji, Kui Wang, Haiyan Jin, Pei Sun Loh
Open Journal of Marine Science (OJMS) , 2016, DOI: 10.4236/ojms.2016.61010
Abstract: In this study, a comparison was made between the Changjiang Estuary and the Hanghzou Bay, in terms of the sources and diagenesis of the sedimentary organic matter (OM). To achieve this purpose, surface sediments from the estuary and bay were analyzed for lignin-derived phenols, stable carbon isotope and TOC/TN (total organic carbon/total nitrogen) molar ratio. The signal of land-derived OM decreased, and the vanillic acid to vanillin ratio, (Ad/Al)v, increased with increasing distance from the Changjiang Estuary and the Hangzhou Bay. These results corresponded with the contribution of the terrigenous OM from the rivers to the coastal zone, and the predominance ofmarine OM farther offshore, and that the land-derived OM underwent decomposition duringtransport along the estuary and bay. It should be noted that besides the Qiantang River, Hangzhou Bay is also receiving more than half of its materials from Changjiang Estuary, which flows into the Hangzhou Bay at the north, and leaves via the southern part of the bay. This important aspect of the hydrological cycle in Hangzhou Bay corresponded to higher Λ (total lignin in mg/100 mg OC), higher TOC and C/N ratios and more elevated (Ad/Al)v and (Ad/Al)s values in the bay than the Changjiang Estuary, thus, rendering the bay as a site for the accumulation and rapid cycling of terrigenous OM.
The Unity of Scientific Literacy Education and Humanistic Spirit Education in Higher Education  [PDF]
Shixin Pei, Fenping Cui, Tingting Sun
Creative Education (CE) , 2012, DOI: 10.4236/ce.2012.37B032
Abstract:

In view of the irrational phenomenon of many highly educated intellectuals showed non-rational behavior; it consider that the reason for this non-rational behavior is caused by the artificial fragmentation of scientific attainment education and humanistic spirit education in modern China higher education. This article maintains that healthy higher education should be based on scientific literacy, oriented by humanistic spirit, and to aim at the promotion of students personality perfection. Based on these, this paper ideal is the unity of human spirit education and science literacy education in modern Chinese colleges and universities is need urgently, that is to fully integrate the human spirit and science literacy, practice the way of the combination of science and humanities education. Focus on the combination, the connotations, objectives and ways to realize are disscussed in this paper, it is thinking that practices the combination of science and humanities education way should develop education theory, establish the educational methodology suitable for the science and humanities education, and seek the reuniting of science and humanities education from the history of science literacy education and humanities spirits education, reform the probleme in the combination of science education and humanities education, to carry out the education of science and humanities at the same time, reshaping the values of today higher education.

Role of Investigating Thrombophilic Disorders in Young Stroke
Kay W. P. Ng,Pei K. Loh,Vijay K. Sharma
Stroke Research and Treatment , 2011, DOI: 10.4061/2011/670138
Abstract: Our knowledge about various inherited and acquired causes of thrombophilic disorders has increased significantly during the past decade. Technology for various diagnostic tests for these rare disorders has matched the rapid advances in our understanding about the thrombophilic disorders. Inherited thrombophilic disorders predispose young patients for various venous or arterial thrombotic and thromboembolic episodes. Our understanding has also improved about various gene-gene and gene-environment interactions and their impact on the resultant heterogenous clinical manifestations. We describe various thrombophilic disorders, their diagnostic tests, pathogenic potential in isolation or with other concurrent inherited/acquired defects and possible therapeutic and prophylactic strategies. Better understanding, optimal diagnostic and screening protocols are expected to improve the diagnostic yield and help to reduce morbidity, disability, and mortality in relatively younger patients harbouring these inherited and acquired thrombophilic disorders. 1. Introduction Ischemic stroke (IS) is a common cause of morbidity and mortality with significant socioeconomic impact especially when it affects young patients. The incidence of ischemic stroke varies from 3 to 23 per 100,000 among the young IS sufferers [1]. Although the cutoff age for defining young IS remains debatable, it is generally believed that the risk factors and underlying etiologies tend to become similar to the older patients at around 44 years of age. Therefore, most of the studies define “stroke in young” as occurring in patients at age 44 years or less [2]. Young strokes generate immense interest among the stroke neurologists even when a larger proportion of patients continue to be classified as “stroke of undetermined etiology” [2]. Compared to the older adults, the incidence, risk factors, and etiology are distinctly different in younger IS. Accordingly, cardioembolism (20%–35%), dissection of extracranial arteries (6%–25%), drugs (10%), and hypercoagulable states (5%–10%) are relatively more commonly detected in younger IS patients [3–5]. Furthermore, additional factors such as migraine, pregnancy and oral contraceptive use are observed with higher frequency [4, 5]. Young IS attracts a barrage of diagnostic tests, mainly searching for an underlying thrombophilic state. We discuss various thrombophilic disorders, their available diagnostic tests and significance of testing for these uncommon causes. 2. Thrombophilic Disorders and Ischemic Stroke Thrombophilic states are disorders of hemostatic
Strain dependence of the heat transport properties of graphene nanoribbons
Pei Shan Emmeline Yeo,Kian Ping Loh,Chee Kwan Gan
Physics , 2013, DOI: 10.1088/0957-4484/23/49/495702
Abstract: Using a combination of accurate density-functional theory and a nonequilibrium Green function's method, we calculate the ballistic thermal conductance characteristics of tensile-strained armchair (AGNR) and zigzag (ZGNR) edge graphene nanoribbons, with widths between 3-50 \AA. The optimized lateral lattice constants for AGNRs of different widths display a three-family behavior when the ribbons are grouped according to N modulo 3, where $N$ represents the number of carbon atoms across the width of the ribbon. Two lowest-frequency out-of-plane acoustic modes play a decisive role in increasing the thermal conductance of AGNR-N at low temperatures. At high temperatures the effect of tensile strain is to reduce the thermal conductance of AGNR-N and ZGNR-N. These results could be explained by the changes in force constants in the in-plane and out-of-plane directions with the application of strain. This fundamental atomistic understanding of the heat transport in graphene nanoribbons paves a way to effect changes in their thermal properties via strain at various temperatures.
Boundary Induced Inductive Delay in Transmission of Electromagnetic Signals  [PDF]
Yong Yang, Mingzhi Li, Yan Sun, Dongfei Pei, Shengyong Xu
Journal of Electromagnetic Analysis and Applications (JEMAA) , 2012, DOI: 10.4236/jemaa.2012.44020
Abstract: When an electromagnetic signal transmits through a coaxial cable, it propagates at speed determined by the dielectrics of insulator between the cooper core wire and the metallic shield. However, we demonstrate here that, once the shielding layer of the coaxial cable is cut into two parts leaving a small gap, while the copper core wire is still perfectly connected, a remarkable transmission delay immediately appears in the system. We have revealed by both computational simulation and experiments that, when the gap spacing between two parts of the shielding layer is small, this delay is mostly determined by the overall geometrical parameters of the conductive boundary which connects two parts of the cut shielding layer. A reduced analytic formula for the transmission delay related with geometrical parameters, which is based on an inductive model of the transmission system, matches well with the fitted formula of the simulated delay. This above structure is analog to the situation that an interconnect is between two inter-modules in a circuit. The results suggest that for high speed circuits and systems, parasitic inductance should be taken into full consideration, and compact conductive packaging is favorable for reducing transmission delay of inter-modules, therefore enhancing the performance of the system.
Identification of N-Methyl Bis(2-(Alkyloxy-Alkylphosphoryloxy)Ethyl) Amines by LC-HRMS/MS  [PDF]
Huilan Yu, Shilei Liu, Daoming Sun, Chengxin Pei, Yu Xiang
American Journal of Analytical Chemistry (AJAC) , 2014, DOI: 10.4236/ajac.2014.513091
Abstract: N-Methyl bis(2-(alkyloxy-alkylphosphoryloxy)ethyl)amines, which are abbreviated as PNPs, are a series of new skeleton chemicals belonging to schedule 2.B.04 chemicals of Chemical Weapons Convention (CWC). PNPs are important markers of chemical warfare agents because they are structurally relative to both nerve agents and N-mustards. In this study, fragmentation pathways of the most characteristic fragment ions in Q-TOF mass spectrometry were proposed based on the information from accurate mass and secondary fragmentations of product ions scan experiments. Results indicated that the base ion in LC/HRMS was the quasi-molecular ion [M+H]+. In LC-HRMS/MS, it was [M+H-CnH2n+1P(O)(OH)CmH2m+1O]+ fragment ion which was formed by losing an alkyloxy alkylphosphoryloxy group from the quasi-molecular ion. The diagnostic ion m/z84.0814 was identified as [C5H10N]+, which was the group of (CH2=CH)2N+(H)CH3. PNPs have two protonated centers. One is on the N atom, the other is on the O atom (P=O). O-n-propyl PNPs generally exhibited two fragmentation pathways. Firstly, the quasi-molecular ion [M+H]+ lost a propoxy alkylphosphoryloxy group to produce
An fMRI Study of Words Processing in Chinese Language  [PDF]
Pei Xu, Bing Sun, Chunqi Chang, Nan Hu
Journal of Biosciences and Medicines (JBM) , 2016, DOI: 10.4236/jbm.2016.43002
Abstract:

Using the blood oxygen levels dependent technology of magnetic resonance imaging (BLOD-fMRI), we aimed to explore the brain activation after visual stimulation by Chinese words. In the current study, 24 healthy volunteers (12 males, 12 females, right-handed, mean age 26 ± 2 years) were prospectively included. The event related design was used in the current fMRI study when participants silently read all words appearing in the middle of the screen. Images were processed with Statistical Parametric Mapping 8 (SPM8) software, by using a general linear model (GLM). Group activations were extracted from the 2nd level group analysis with a threshold of p < 0.001, and it was shown that the main activated areas by silent reading tasks were regions involved in brain semantic processing, including middle temporal gyrus, fusiform gyrus, supplementary motor area, inferior frontal gyrus, cingulate gyrus, superior parietal lobule and inferior parietal lobule. It was also learnt that superior parietal lobule and middle temporal gyrus are related with semantic understanding, lenticular nucleus are related with semantic processing. This means, in addition to the cerebral cortex, subcortical nuclei is also very important to the processing of words in Chinese language.

Comprehensive profiling of DNA methylation in colorectal cancer reveals subgroups with distinct clinicopathological and molecular features
Pei Ang, Marie Loh, Natalia Liem, Pei Lim, Fabienne Grieu, Aparna Vaithilingam, Cameron Platell, Wei Yong, Barry Iacopetta, Richie Soong
BMC Cancer , 2010, DOI: 10.1186/1471-2407-10-227
Abstract: DNA methylation at 1,505 CpG sites in 807 cancer-related genes was evaluated using the Illumina GoldenGate? methylation array in 28 normal colonic mucosa and 91 consecutive CRC samples. Methylation data was analyzed using unsupervised hierarchical clustering. CIMP subgroups were compared for various clinicopathological and molecular features including patient age, tumor site, microsatellite instability (MSI), methylation at a consensus panel of CpG islands and mutations in BRAF and KRAS.A total of 202 CpG sites were differentially methylated between tumor and normal tissue. Unsupervised hierarchical clustering of methylation data from these sites revealed the existence of three CRC subgroups referred to as CIMP-low (CIMP-L, 21% of cases), CIMP-mid (CIMP-M, 14%) and CIMP-high (CIMP-H, 65%). In comparison to CIMP-L tumors, CIMP-H tumors were more often located in the proximal colon and showed more frequent mutation of KRAS and BRAF (P < 0.001).Comprehensive DNA methylation profiling identified three CRC subgroups with distinctive clinicopathological and molecular features. This study suggests that both KRAS and BRAF mutations are involved with the CIMP-H pathway of CRC rather than with distinct CIMP subgroups.DNA hypermethylation-induced gene silencing is a common event in many malignancies and serves as an alternative mechanism to genetic mutation for the loss of tumor suppressor functions [1,2]. Although the mechanisms that underlie aberrant DNA methylation in cancer cells remain to be elucidated, current evidence suggests that it may be an early and possibly even an initiating event in the development of colorectal cancer (CRC).A subset of CRC has been shown to exhibit frequent and concurrent hypermethylation at specific gene promoters and is referred to as the CpG island methylator phenotype (CIMP+) [3]. CIMP+ CRC is associated with distinct clinicopathological and molecular features including proximal tumor location, preponderance in elderly females, poorly diffe
First-principles study of the thermoelectric properties of strained graphene nanoribbons
Pei Shan Emmeline Yeo,Michael B. Sullivan,Kian Ping Loh,Chee Kwan Gan
Physics , 2013, DOI: 10.1039/c3ta12211e
Abstract: We study the transport properties, in particular, the thermoelectric figure of merit ZT of armchair graphene nanoribbons, AGNR-N (for N=4-12, with widths ranging from 3.7 to 13.6~\AA) through strain engineering, where N is the number of carbon dimer lines across the AGNR width. We find that the tensile strain applied to AGNR-$N$ changes the transport properties by modifying the electronic structures and phonon dispersion relations. The tensile strain increases the ZT value of the AGNR-$N$ families with N=3p and N=3p+2, where $p$ is an integer. Our analysis based on accurate density-functional theory calculations suggests a possible route to increase the ZT values of AGNR-$N$ for potential thermoelectric applications.
Evolutionary Gaming Analysis of Path Dependence in Green Construction Technology Change  [PDF]
Xian-Feng Zhang, Chuan-Min Shuai, Pei-Song Gong, Han Sun
iBusiness (IB) , 2012, DOI: 10.4236/ib.2012.43024
Abstract: In the context of instigating green construction technology by changing current technology practices, evolutionary game theory is used to solve path dependence problems that yield stable equilibrium. Replicating dynamic gaming shows that in inducing technological change some problems concerning multiple equilibrium definitely exist and that profit is the prime motivation to use or supply new technology. The model also shows that a lock-in of a current tech-nology can be broken as a consequence of players’ studies.
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