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Search Results: 1 - 10 of 15946 matches for " Mei-Heng Yueh "
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Graph invariants from ideas in physics and number theory
An Huang,Shing-Tung Yau,Mei-Heng Yueh
Mathematics , 2014,
Abstract: We study free scalar field theory on a graph, which gives rise to a modified version of discrete Green's function on a graph studied in \cite{CY}. We show that this gives rise to a graph invariant, which is closely related to the 2-dim Weisfeiler-Lehman algorithm for graph isomorphism testing. We complement this invariant by another type of graph invariants, coming from viewing graphs as quadratic forms over the integers. We explain that the combination of these two ideas give rise to an interesting approach to the graph isomorphism problem.
Conformal Surface Morphing with Applications on Facial Expressions
Mei-Heng Yueh,Xianfeng David Gu,Wen-Wei Lin,Chin-Tien Wu,Shing-Tung Yau
Computer Science , 2015,
Abstract: Morphing is the process of changing one figure into another. Some numerical methods of 3D surface morphing by deformable modeling and conformal mapping are shown in this study. It is well known that there exists a unique Riemann conformal mapping from a simply connected surface into a unit disk by the Riemann mapping theorem. The dilation and relative orientations of the 3D surfaces can be linked through the M\"obius transformation due to the conformal characteristic of the Riemann mapping. On the other hand, a 3D surface deformable model can be built via various approaches such as mutual parameterization from direct interpolation or surface matching using landmarks. In this paper, we take the advantage of the unique representation of 3D surfaces by the mean curvatures and the conformal factors associated with the Riemann mapping. By registering the landmarks on the conformal parametric domains, the correspondence of the mean curvatures and the conformal factors for each surfaces can be obtained. As a result, we can construct the 3D deformation field from the surface reconstruction algorithm proposed by Gu and Yau. Furthermore, by composition of the M\"obius transformation and the 3D deformation field, the morphing sequence can be generated from the mean curvatures and the conformal factors on a unified mesh structure by using the cubic spline homotopy. Several numerical experiments of the face morphing are presented to demonstrate the robustness of our approach.
A Regularized Newton Method with Correction for Unconstrained Convex Optimization  [PDF]
Liming Li, Mei Qin, Heng Wang
Open Journal of Optimization (OJOp) , 2016, DOI: 10.4236/ojop.2016.51006
Abstract: In this paper, we present a regularized Newton method (M-RNM) with correction for minimizing a convex function whose Hessian matrices may be singular. At every iteration, not only a RNM step is computed but also two correction steps are computed. We show that if the objective function is LC2, then the method posses globally convergent. Numerical results show that the new algorithm performs very well.
Liver-Specific Expressions of HBx and src in the p53 Mutant Trigger Hepatocarcinogenesis in Zebrafish
Jeng-Wei Lu, Wan-Yu Yang, Su-Mei Tsai, Yueh-Min Lin, Pen-Heng Chang, Jim-Ray Chen, Horng-Dar Wang, Jen-Leih Wu, Shiow-Lian Catherine Jin, Chiou-Hwa Yuh
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0076951
Abstract: Hepatocarcinogenesis is a multistep process that starts from fatty liver and transitions to fibrosis and, finally, into cancer. Many etiological factors, including hepatitis B virus X antigen (HBx) and p53 mutations, have been implicated in hepatocarcinogenesis. However, potential synergistic effects between these two factors and the underlying mechanisms by which they promote hepatocarcinogenesis are still unclear. In this report, we show that the synergistic action of HBx and p53 mutation triggers progressive hepatocellular carcinoma (HCC) formation via src activation in zebrafish. Liver-specific expression of HBx in wild-type zebrafish caused steatosis, fibrosis and glycogen accumulation. However, the induction of tumorigenesis by HBx was only observed in p53 mutant fish and occurred in association with the up-regulation and activation of the src tyrosine kinase pathway. Furthermore, the overexpression of src in p53 mutant zebrafish also caused hyperplasia, HCC, and sarcomatoid HCC, which were accompanied by increased levels of the signaling proteins p-erk, p-akt, myc, jnk1 and vegf. Increased expression levels of lipogenic factors and the genes involved in lipid metabolism and glycogen storage were detected during the early stages of hepatocarcinogenesis in the HBx and src transgenic zebrafish. The up-regulation of genes involved in cell cycle regulation, tumor progression and other molecular hallmarks of human liver cancer were found at later stages in both HBx and src transgenic, p53 mutant zebrafish. Together, our study demonstrates that HBx and src overexpression induced hepatocarcinogenesis in p53 mutant zebrafish. This phenomenon mimics human HCC formation and provides potential in vivo platforms for drug screening for therapies for human liver cancer.
Functional analysis of conserved aromatic amino acids in the discoidin domain of Paenibacillus β-1,3-glucanase
Yueh-Mei Cheng, Feng-Chia Hsieh, Menghsiao Meng
Microbial Cell Factories , 2009, DOI: 10.1186/1475-2859-8-62
Abstract: The discoidin domain (DS domain) is a structural and functional motif that is appended, singly or in tandem, to various eukaryotic and prokaryotic proteins [1]. The first DS domain was identified in the amoeba Dictyostelium discoideum and described as a lectin with high affinity for galactose and galactose derivatives [2]. It should be noted that the domain is also referred to as F5/8C due to its presence at the carboxyl-terminus of blood coagulation factors V and VIII. The DS domain binds a wide variety of ligand molecules, including phospholipids, carbohydrates, and partner proteins, thus enabling its cognate protein to participate in various physiological functions such as cellular adhesion [3,4], migration [5], neural development [6,7], and nutrition assimilation [8,9]. A subgroup of the domain possessing carbohydrate-binding ability is also classified as the carbohydrate-binding module family 32 (CBM32) [10]. Due to the recent progress of genome projects, the number of CBM32 members has increased significantly over a short period time. However, most of these members have not been functionally characterized.The structure of several DS domains has been determined and deposited in the PDB [11]. The DS domain comprises approximately 150 amino acid residues, arranged into a β-sandwich fold with several flexible loops. Presumably, the β-sandwich fold is stabilized predominantly by hydrophobic interactions. The variability within the loops has been suggested to account for the diverse binding spectrum of the DS domain [12]. Co-crystallizations of CBM32 members and their ligands, such as the module of Clostridium perfringens N-acetylglucosaminidase with β-galactosyl-1,4-β-N-acetylglucosamine or the module of Micromonospora viridifaciens sialidase with lactose, demonstrate that the protruding loops form the ligand binding site [13,14].Recently, a β-1,3-glucanase consisting of 1793 amino acid residues [GenBank: DQ987544] was isolated from Paenibacillus sp. BCRC 17245 and
圖書資訊學期刊自我引用分析 A Self Citation Study on Journals of Library and Information Science
Ming-Yueh Tsay,Mei-Chi Chang
Journal of Educational Media & Library Sciences , 2008,
Abstract: 本文就2005年社會科學引文索引(Social Sciences Citation Index)之期刊引用報告(Journal Citation Reports)資料庫,所收錄53種圖書資訊學期刊之引用數據特性,加以分析介紹,進而就期刊同時法自我引用、期刊歷時法自我引用與各引用數據之相關性,分別進行統計檢測,並就二種自我引用率驗證其異同。 By searching the Journal Citation Reports of Social Sciences Citation Index database, this study investigates the characteristics and compares the difference on citation data for 53 journals of library and information science. The journal citation data that were explored include cited times, impact factor, immediacy index, citing half-life, cited half-life, self-citing rate (synchronous self-citation) and self cited rate (diachronous self-citation). Moreover, the relationship between each citation data and two self-citation rates, and the mean difference between two self-citation rates are examined by statistical tests.
Functional analysis of conserved aromatic amino acids in the discoidin domain of Paenibacillus β-1,3-glucanase
Cheng Yueh-Mei,Hsieh Feng-Chia,Meng Menghsiao
Microbial Cell Factories , 2009,
Abstract: The 190-kDa Paenibacillus β-1,3-glucanase (LamA) contains a catalytic module of the glycoside hydrolase family 16 (GH16) and several auxiliary domains. Of these, a discoidin domain (DS domain), present in both eukaryotic and prokaryotic proteins with a wide variety of functions, exists at the carboxyl-terminus. To better understand the bacterial DS domain in terms of its structure and function, this domain alone was expressed in Escherichia coli and characterized. The results indicate that the DS domain binds various polysaccharides and enhances the biological activity of the GH16 module on composite substrates. We also investigated the importance of several conserved aromatic residues in the domain's stability and substrate-binding affinity. Both were affected by mutations of these residues; however, the effect on protein stability was more notable. In particular, the forces contributed by a sandwiched triad (W1688, R1756, and W1729) were critical for the presumable β-sandwich fold.
The role of thrombomodulin lectin-like domain in inflammation
Yi-Heng Li, Cheng-Hsiang Kuo, Guey-Yueh Shi, Hua-Lin Wu
Journal of Biomedical Science , 2012, DOI: 10.1186/1423-0127-19-34
Abstract: Thrombomodulin (TM) is a cell surface-expressed transmembrane glycoprotein which is originally identified on vascular endothelium. The cDNA sequence of TM has been determined with the cloning and sequencing of the human TM gene [1]. The mature human TM protein and its secondary structure have also been resolved [2]. TM protein has 557 amino acids, and its structure consists of 5 domains including a highly charged N-terminal lectin-like domain (D1), a domain with six epidermal growth factor (EGF)-like structures (D2), a serine and threonine-rich domain (D3), a transmembrane domain (D4) and a cytoplasmic domain (D5) [2] (Figure 1). TM on vascular endothelial cells is an important molecule in human natural anticoagulation system. After a stimulus, blood coagulation cascade amplifies and produces a high level of thrombin, the key effector of coagulation cascade. Natural anticoagulant mechanisms are activated to prevent excessive thrombin generation. TM acts as a thrombin receptor on the surface of vascular endothelial cells. The binding of TM to thrombin significantly decreases the thrombin's effect in conversion of fibrinogen to fibrin, and activation of coagulation factor V, VIII and platelet. Thrombin-TM complex catalyzes the activation of protein C about 1000 times faster than free thrombin. Activated protein C proteolytically inactivates the coagulation cofactor Va and VIIIa, thereby inhibiting the amplification of the coagulation system [3-5]. The importance of TM in natural anticoagulant system was demonstrated by the observation that transgenic mice with endothelium-specific loss of TM developed severe spontaneous thrombosis in the arterial and venous circulation, and inevitably led to the death of animal [6]. In addition to endothelium, TM is expressed in smooth muscle cell [7], platelet [8], monocyte [9], and cardiomyocyte [10]. TM is also expressed in some cancer cells and influences the growth and metastasis of cancer [11,12]. The presence of TM in these cel
Chilaiditi Syndrome: The Pitfalls of Diagnosis  [PDF]
Chien-Hua Lin, Jyh-Cherng Yu, Jing-Jim Ou, Yueh-Tsung Lee, Mei Huang, Hurng-Sheng Wu
Surgical Science (SS) , 2012, DOI: 10.4236/ss.2012.33028
Abstract: Purpose: Chilaiditi’s syndrome is the hepatodiaphragmatic interposition of the colon. Its diagnosis poses challenge to clinicians, and misdiagnosis may results in unnecessary exploratory laparotomy being performed. The purpose of this study was to report our experience in diagnosis, management, and clinical outcome of patients with Chilaiditi’s syndrome. Methods: Nine cases of Chilaiditi’s syndrome from April 2005 to January 2007 at one institute. The clinical characteristic, imaging studies, management and results were recorded. Results: Six patients presented with abdominal distension (2 patients with abdominal pain; 5 patients with constipation), while Chilaiditi’s syndrome in the other three patients were found incidentally. All patients underwent chest X-ray. The Chilaiditi’s sign could be detected in seven patients; while the other two patients presented with no specific finding. Abdominal plain films (KUB) were all reviewed. Most of the patients (n = 8) showed ileus and one patient showed no specific finding. Impacted stool could be detected in five of nine patients. Abdominal ultrasound was performed in two patients. Gallstones were detected in one of them while the other revealed no specific finding. Six of nine patients underwent CT of abdomen, one of them revealed bowel loops in bilateral subphrenic space. One patient underwent subtotal colectomy because of volvulus of sigmoid colon. Five patients were treated with laxative and enema successfully and had been remained asymptomaticcally for a mean follow-up of 6.6 months. The other three cases were under observation. Conclusions: Presence of haustral folds of bowel loops may help us in diagnosing Chilaiditi’s syndrome. The left lateral decubitus abdominal plain film can also help to differentiate between pneumoperitoneum to Chilaiditi’s sign. Most of the cases with Chilaiditi’s syndrome can be resolved with conservative treatment and surgical intervention was reserved for patients with sign of systemic toxicity or peritonitis.
Molecular Identification of Fusarium Species in Gibberella fujikuroi Species Complex from Rice, Sugarcane and Maize from Peninsular Malaysia
Heng Mei Hsuan,Baharuddin Salleh,Latiffah Zakaria
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12106722
Abstract: The objective of this study was to identify Fusarium species in the Gibberella fujikuroi species complex from rice, sugarcane and maize as most of the Fusarium species in the species complex are found on the three crops. Isolates used were collected from the field and obtained from culture collection. The Fusarium isolates were initially sorted based on morphology and identifications confirmed based on the DNA sequence of the translation elongation factor 1-α (TEF-1α) gene. Based on the closest match of BLAST analysis, five species were recovered, namely, F. sacchari, F. fujikuroi, F. proliferatum, F. andiyazi and F. verticillioides. This is the first report regarding F. andiyazi from rice in Malaysia and Southeast Asia. The phylogenetic tree generated by using the neighbor joining method showed that isolates from the same species were grouped in the same clade. The present study indicated that Fusarium species in the G. fujikuroi species complex are widespread in rice, sugarcane and maize in Peninsular Malaysia. The findings also suggest that the use of morphological characters for identification of Fusarium species in the G. fujikuroi species complex from the three crops will lead to incorrect species designation.
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