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Search Results: 1 - 10 of 17865 matches for " Kin-Fu Chak "
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A Study of the Wound Healing Mechanism of a Traditional Chinese Medicine, Angelica sinensis, Using a Proteomic Approach
Chia-Yen Hsiao,Ching-Yi Hung,Tung-Hu Tsai,Kin-Fu Chak
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/467531
Abstract: Angelica sinensis (AS) is a traditional Chinese herbal medicine that has been formulated clinically to treat various form of skin trauma and to help wound healing. However, the mechanism by which it works remains a mystery. In this study we have established a new platform to evaluate the pharmacological effects of total AS herbal extracts as well as its major active component, ferulic acid (FA), using proteomic and biochemical analysis. Cytotoxic and proliferation-promoting concentrations of AS ethanol extracts (AS extract) and FA were tested, and then the cell extracts were subject to 2D PAGE analysis. We found 51 differentially expressed protein spots, and these were identified by mass spectrometry. Furthermore, biomolecular assays, involving collagen secretion, migration, and ROS measurements, gave results that are consistent with the proteomic analysis. In this work, we have demonstrated a whole range of pharmacological effects associated with Angelica sinensis that might be beneficial when developing a wound healing pharmaceutical formulation for the herbal medicine.
The Molecular Basis of Wound Healing Processes Induced by Lithospermi Radix: A Proteomics and Biochemical Analysis
Chia-Yen Hsiao,Tung-Hu Tsai,Kin-Fu Chak
Evidence-Based Complementary and Alternative Medicine , 2012, DOI: 10.1155/2012/508972
Abstract: Lithospermi Radix (LR) is an effective traditional Chinese herb in various types of wound healing; however, its mechanism of action remains unknown. A biochemical and proteomic platform was generated to explore the biological phenomena associated with LR and its active component shikonin. We found that both LR ethanol extracts and shikonin are able to promote cell proliferation by up to 25%. The results of proteomic analysis revealed that twenty-two differentially expressed proteins could be identified when fibroblast cells were treated with LR or shikonin. The functions of those proteins are associated with antioxidant activity, antiapoptosis activity, the regulation of cell mobility, the secretion of collagen, the removal of abnormal proteins, and the promotion of cell proliferation, indicating that the efficacy of LR in wound healing may be derived from a synergistic effect on a number of factors induced by the herbal medicine. Furthermore, an animal model confirmed that LR is able to accelerate wound healing on the flank back of the SD rats. Together these findings help to pinpoint the molecular basis of wound healing process induced by LR.
Repression of btuB gene transcription in Escherichia coli by the GadX protein
Guang-Sheng Lei, Wan-Jr Syu, Po-Huang Liang, Kin-Fu Chak, Wensi S Hu, Shiau-Ting Hu
BMC Microbiology , 2011, DOI: 10.1186/1471-2180-11-33
Abstract: To determine whether the btuB gene is also transcriptionally controlled by trans-acting factors, a genomic library was screened for clones that enable E. coli to grow in the presence of colicin E7, and a plasmid carrying gadX and gadY genes was isolated. The lacZ reporter gene assay revealed that these two genes decreased the btuB promoter activity by approximately 50%, and the production of the BtuB protein was reduced by approximately 90% in the presence of a plasmid carrying both gadX and gadY genes in E. coli as determined by Western blotting. Results of electrophoretic mobility assay and DNase I footprinting indicated that the GadX protein binds to the 5' untranslated region of the btuB gene. Since gadX and gadY genes are more highly expressed under acidic conditions, the transcriptional level of btuB in cells cultured in pH 7.4 or pH 5.5 medium was examined by quantitative real-time PCR to investigate the effect of GadX. The results showed the transcription of gadX with 1.4-fold increase but the level of btuB was reduced to 57%.Through biological and biochemical analysis, we have demonstrated the GadX can directly interact with btuB promoter and affect the expression of btuB. In conclusion, this study provides the first evidence that the expression of btuB gene is transcriptionally repressed by the acid responsive genes gadX and gadY.BtuB (B twelve uptake) is a 614 amino acid outer membrane protein of Escherichia coli. It is responsible for the uptake of cobalamins [1], such as vitamin B12 including cyanocobalamin, hydroxocobalamin, methylcobalamin, and adenosylcobalamin[2]. It also serves as the receptor for bacteriophage BF23 [3]. The synthesis of the BtuB protein in E. coli is regulated at the translational level by adenosylcobalamin (Ado-Cbl) which is produced by the BtuR protein (CobA in Salmonella typhimurium and CobO in Pseudomonas denitrificans) [4-6]. BtuR is an ATP:corrinoid adenosyltransferase and converts cobalamins to Ado-Cbl [4]. In the presence
Motor Coordination Training and Pedagogical Approach for Combating Childhood Obesity  [PDF]
Allan Chak Lun Fu, Stephen Paul Cobley, Ross Howard Sanders
Open Journal of Social Sciences (JSS) , 2016, DOI: 10.4236/jss.2016.412001
Abstract:
Evidence suggests that obesity is strongly associated with low physical activity (PA). Overcoming the obesity problem requires that individuals adhere to prescribed PA programs. Therefore, in this paper we review the factors affecting adherence. On the basis of the review we recommend a strategy for developing movement competence and enjoyment of PA to improve adherence and long term participation in PA. The relationships among childhood obesity, level of PA, and movement competence indicated by motor coordination (MC) and development of fundamental movement skills (FMS) were reviewed, followed by an assessment of current pedagogical and psychological principles leading to the proposal of a strategic approach to improve long term PA adherence. Many children are affected by a “vicious cycle of obesity”, low PA, and low levels of movement competence perpetuating avoidance of PA. Intervention programmes to break the vicious cycle should be based on skill development needs of individuals. The program should be designed and delivered in a manner that fosters a task-based psycho-social climate based on self-determination and achievement goal theories. MC training reinforced by a favourable psycho-social climate can be effective in breaking a “vicious cycle of obesity” and increasing PA adherence.
On the Eulerian Polynomials of Type D
Chak-On Chow
Mathematics , 2002,
Abstract: We introduce sub-Eulerian polynomials to count elements of $D_n$ by which a recurrence relation for the Eulerian polynomials of type $D$ is obtained.
Abnormalities in circulating plasmacytoid dendritic cells in patients with systemic lupus erythematosus
Ou Jin, Sushma Kavikondala, Mo-Yin Mok, Lingyun Sun, Jieruo Gu, Rong Fu, Albert Chan, Joseph Yeung, Yingjie Nie, Chak-Sing Lau
Arthritis Research & Therapy , 2010, DOI: 10.1186/ar3075
Abstract: Peripheral blood pDCs from 62 healthy subjects and 58 SLE patients were treated with apoptotic cells derived from polymorphonuclear cells (PMNs). Antigen loaded or unloaded pDCs were then co-cultured with autologous or allogenous T cells. Changes in T cell proliferation, cell surface CD25 expression, intracellular Foxp3 expression and cytokine production were evaluated. pDCs that had captured apoptotic PMNs (pDCs + apoPMNs were also studied for their cytokine production (interferon (IFN)-alpha, interleukin (IL)-6, IL-10, IL-18) and toll like receptor (TLR) expression.Circulating pDCs from SLE patients had an increased ability to stimulate T cells when compared with control pDCs. Using allogenous T cells as responder cells, SLE pDCs induced T cell proliferation even in the absence of apoptotic PMNs. In addition, healthy pDCs + apoPMNs induced suppressive T regulatory cell features with increased Foxp3 expression in CD4 + CD25 + cells while SLE pDCs + apoPMNs did not. There were differences in the cytokine profile of pDCs that had captured apoptotic PMNs between healthy subjects and patients with SLE. Healthy pDCs + apoPMNs showed decreased production of IL-6 but no significant changes in IL-10 and IL-18. These pDCs + apoPMNs also showed increased mRNA transcription of TLR9. On the other hand, while SLE pDCs + apoPMNs also had decreased IL-6, there was decreased IL-18 mRNA expression and persistent IL-10 protein synthesis. In addition, SLE pDCs lacked TLR9 recruitment.We have demonstrated that peripheral circulating pDCs in patients with SLE were functionally abnormal. They lacked TLR9 expression, were less capable of inducing regulatory T cell differentiation and had persistent IL-10 mRNA expression following the capture of apoptotic PMNs. We suggest circulating pDCs may be pathogenically relevant in SLE.Dendritic cells (DCs) are professional antigen presenting cells (APCs) with important immunoregulatory functions. They are the only cells that can stimulate na?ve T
Finite Element Analysis of Contact Pressures between Seat Cushion and Human Buttock-Thigh Tissue  [PDF]
Chak Yin Tang, Wai Chan, Chi Pong Tsui
Engineering (ENG) , 2010, DOI: 10.4236/eng.2010.29093
Abstract: Unrelieved pressure on load-bearing muscle tissues of humans can produce pressure ulcers. In a seated upright posture, the highest pressures occur inferior to the ischial tuberosities (ITs). Moreover, the vibration can initiate the development of pressure ulcer. Therefore, the seat cushion is not only used to lower the maximum seating pressure on buttocks but also minimize the transmission of vibration to human body. The purpose of this study was to investigate the effects of varying vertical vibration frequencies on seat-interface contact pressure during sitting on three different seat cushions by using a finite element modeling approach. A simplified two-dimensional human buttock-thigh model was developed to simulate the mechanical response of the muscle of buttocks and thigh under vertical vibration. Static and vibrational loads with five different frequencies of 0.1, 1, 10, 30 and 50 Hz and the same amplitude of 3 mm were applied to different seat cushions. The result showed that the “SAF 6060” seat cushion with both hyperelastic and viscoelastic behaviors could be effective in reducing the amplitude of varying maximum contact pressure, especially for the frequency of 10-20 Hz. This method could help in design of seat cushions with appropriate material properties and shape so as to reduce vibrations transmitted to human body at a certain frequency range.
Self-Dictionary Sparse Regression for Hyperspectral Unmixing: Greedy Pursuit and Pure Pixel Search are Related
Xiao Fu,Wing-Kin Ma,Tsung-Han Chan,José M. Bioucas-Dias
Mathematics , 2014, DOI: 10.1109/JSTSP.2015.2410763
Abstract: This paper considers a recently emerged hyperspectral unmixing formulation based on sparse regression of a self-dictionary multiple measurement vector (SD-MMV) model, wherein the measured hyperspectral pixels are used as the dictionary. Operating under the pure pixel assumption, this SD-MMV formalism is special in that it allows simultaneous identification of the endmember spectral signatures and the number of endmembers. Previous SD-MMV studies mainly focus on convex relaxations. In this study, we explore the alternative of greedy pursuit, which generally provides efficient and simple algorithms. In particular, we design a greedy SD-MMV algorithm using simultaneous orthogonal matching pursuit. Intriguingly, the proposed greedy algorithm is shown to be closely related to some existing pure pixel search algorithms, especially, the successive projection algorithm (SPA). Thus, a link between SD-MMV and pure pixel search is revealed. We then perform exact recovery analyses, and prove that the proposed greedy algorithm is robust to noise---including its identification of the (unknown) number of endmembers---under a sufficiently low noise level. The identification performance of the proposed greedy algorithm is demonstrated through both synthetic and real-data experiments.
Semiblind Hyperspectral Unmixing in the Presence of Spectral Library Mismatches
Xiao Fu,Wing-Kin Ma,José Bioucas-Dias,Tsung-Han Chan
Statistics , 2015,
Abstract: The dictionary-aided sparse regression (SR) approach has recently emerged as a promising alternative to hyperspectral unmixing (HU) in remote sensing. By using an available spectral library as a dictionary, the SR approach identifies the underlying materials in a given hyperspectral image by selecting a small subset of spectral samples in the dictionary to represent the whole image. A drawback with the current SR developments is that an actual spectral signature in the scene is often assumed to have zero mismatch with its corresponding dictionary sample, and such an assumption is considered too ideal in practice. In this paper, we tackle the spectral signature mismatch problem by proposing a dictionary-adjusted nonconvex sparsity-encouraging regression (DANSER) framework. The main idea is to incorporate dictionary correcting variables in an SR formulation. A simple and low per-iteration complexity algorithm is tailor-designed for practical realization of DANSER. Using the same dictionary correcting idea, we also propose a robust subspace solution for dictionary pruning. Extensive simulations and real-data experiments show that the proposed method is effective in mitigating the undesirable spectral signature mismatch effects.
Joint Tensor Factorization and Outlying Slab Suppression with Applications
Xiao Fu,Kejun Huang,Wing-Kin Ma,Nicholas D. Sidiropoulos,Rasmus Bro
Statistics , 2015,
Abstract: We consider factoring low-rank tensors in the presence of outlying slabs. This problem is important in practice, because data collected in many real-world applications, such as speech, fluorescence, and some social network data, fit this paradigm. Prior work tackles this problem by iteratively selecting a fixed number of slabs and fitting, a procedure which may not converge. We formulate this problem from a group-sparsity promoting point of view, and propose an alternating optimization framework to handle the corresponding $\ell_p$ ($0
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