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ABSTRACT: In this paper, we present the mathematical analysis of two important performance measures for a BitTorrent (BT) like P2P file sharing system, namely, average file downloading time and file availability. For the file downloading time, we develop a model using the "stochastic differential equation" approach, which can capture the system more accurately than some previous approach and can capture various network settings and peers behavior. We study the steady-state behavior and obtain the closed-form solutions for performance measures which allow us to carry sensitivity analysis on various performance measures for various system parameters. We then extend this model to consider multiclass peers wherein some peers are behind firewalls which may impede the uploading service. We also present the mathematical model to study the file availability of a BT-like system. The model helps us gain the understanding of why the "rarest-first" chunk selection policy is used in today's BT protocol. We propose a novel chunk selection algorithm to enhance the overall system file availability. Extensive simulations are carried to validate our analysis
Quality of Service, 2006. IWQoS 2006. 14th IEEE International Workshop on;
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ABSTRACT: Re-epithelialization is a crucial step towards wound healing. The traditional Chinese medicine, Astragalus membranaceus (Fisch) Bge, has been used for hundreds of years for many kinds of ulcerated wounds. Recent research has identified the active compound in this drug as astragaloside IV (AS-IV), but the underlying molecular mechanisms of its therapeutic action on keratinocytes remain poorly understood. In this study, we used an in vitro model of ulcer-like wound processes, lithium chloride (LiCl)-induced cultured mouse keratinocytes, to investigate the effects of AS-IV treatment. The effects on cell proliferation were evaluated by the MTS/PMS colorimetric assay, effects on cell migration were determined by a wound-healing scratch experiment, effects on the cell cycle were analyzed by flow cytometry, and effects on protein expression were analyzed by immunoblotting and immunofluorescence. LiCl strongly inhibited cell proliferation and migration, up-regulated β-catenin expression, and down-regulated proliferating cell nuclear antigen (PCNA) expression. AS-IV treatment attenuat the inhibition of proliferation and migration, significantly reducing the enhanced β-catenin expression, and recovering PCNA and β-tubulin expression. Thus, AS-IV mediates mouse keratinocyte proliferation and migration via regulation of the Wnt signaling pathway. Down-regulating β-catenin to increase keratinocyte migration and proliferation is one mechanism by which AS-IV can promote ulcerated wound healing.
Evidence-based Complementary and Alternative Medicine 01/2012; 2012:956107. · 4.77 Impact Factor
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ABSTRACT: The aim of the present investigation was to elucidate the cellular mechanisms whereby Tanshinone IIA (Tan IIA) leads to cell cycle arrest and apoptosis in vitro in keratinocytes, the target cells in psoriasis. Tan IIA inhibited proliferation of mouse keratinocytes in a dose- and time-dependent manner and induced apoptosis, resulting in S phase arrest accompanied by down-regulation of pCdk2 and cyclin A protein expression. Furthermore, Tan IIA-induced apoptosis and mitochondrial membrane potential changes were also further demonstrated by DNA fragmentation, single-cell gel electrophoresis assay (SCGE), and flow cytometry methods. Apoptosis was partially blocked by the caspase-3 inhibitor Ac-DEVD-CHO. Mitochondrial regulation of apoptosis further downstream was investigated, showing changes in the mitochondrial membrane potential, cytochrome c release into the cytoplasm, and enhanced activation of cleaved caspase-3 and Poly ADP-ribose polymerase (PARP). There was also no translocation of apoptosis-inducing factor (AIF) from mitochondria to the nucleus in apoptotic keratinocytes, indicating Tan IIA-induced apoptosis occurs mainly through the caspase pathway. Our findings provide the molecular mechanisms by which Tan IIA can be used to treat psoriasis and support the traditional use of Salvia miltiorrhiza Bungee (Labiatae) for psoriasis and related skin diseases.
Evidence-based Complementary and Alternative Medicine 01/2012; 2012:927658. · 4.77 Impact Factor
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ABSTRACT: To observe the clinical efficacy of Chinese medicine (CM) treatment of Hongyou Ointment and Shengji Powder on diabetic ulcers, and to observe the influence of CM treatment on the expressions of proteins associated with the Wnt signaling pathway, such as β-catenin, c-myc and K6.
sixty-two patients fitting the registration standards were randomly divided into the CM group (31 patients) and the Western medicine (WM) group (31 patients) by a random number table. The patients in the CM group were treated with Hongyou Ointment and Shengji Powder externally. The patients in the WM group were treated with mupirocin ointment, growth factor (bFGF), and Vaseline gauze for external use and with basic therapies. Wound-healing time and four-week healing rate were recorded. The wounds were measured by digital photography and ImageJ software. Skin biopsies were obtained from 24 patients before CM treatment and 20 patients after CM treatment. Immunohistochemical tests and semi-quantitative imaging with NIH ImageJ 1.42 software were used to analyze the changes in protein expression of β-catenin, c-myc, and K6.
Fifty-three patients completed the trial; four patients in the CM treatment group and five patients in the WM group dropped out. Among them, four were dissatisfied with the treatment process, two could not continue because of their jobs, two failed to complete the course of follow-up appointments, and one was diagnosed with squamous cell carcinoma during treatment. The comparison of ulcer healing rates between the two groups showed insignificant differences (P=0.77). The ulcer healing rates were 33.33% (9/27) in the CM group and 26.92% (7/26) in the WM group. However, the effective rate was significantly higher in the CM group (81.48%, 22/27) than in the WM group (57.69%, 15/26, P=0.04). The mean wound healing time was shorter in the CM group (22.71 ±5.46 days) than in the WM group (26.56 ±7.56 days, P=0.04). CM treatment was well tolerated, and there was no withdrawal due to adverse reactions. Immunohistochemical analysis in the refractory wound indicated higher expressions of β-catenin, c-myc and K6 compared with the normal skin. β-catenin was abnormally expressed in the nuclei of the keratinocytes and fibroblasts at the wound margins, and the expressions of c-myc and K6 were highly expressed in the full hyperplastic epidermis, especially in the granular layer (P<0.05). The expressions of these proteins decreased after CM treatment. The expression levels of β-catenin, c-myc, and K6 proteins before and after the treatment were 101.88 ± 10.76 vs. 140.42 ±8.45; 113.27 ± 16.75 vs. 153.79 ±8.32; 90.39 ±11.07 vs. 151.29 ±7.39, respectively.
CM treatment using Hongyou Ointment and Shengji Powder was efficient in the management of diabetic skin ulcers. The mechanism of action might be related to the inhibition of the Wnt signaling pathway.
Chinese Journal of Integrative Medicine 04/2011; 17(4):261-6. · 0.80 Impact Factor
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Progress in Photovoltaics Research and Applications 11/2010; 19(7):851 - 857. · 5.79 Impact Factor
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ABSTRACT: To study the effects of resolving stagnation and promoting granulation therapy on expressions of Bax and Bcl-2 in granulation tissue of diabetic rats during wound healing.
Seventy-two male SD diabetic rats with full-thickness skin lesion were randomly divided into 3 groups: SJHYR 1-treated group, SJHYR 2-treated group and normal saline (NS) control group. SJHYR 1 was prepared with Shengji Recipe (SJR, a compound traditional Chinese herbal medicine for promoting granulation) and Huayu Recipe (HYR, a compound traditional Chinese herbal medicine for resolving stagnation) at a ratio of 1:2, while SJHYR 2 was prepared with SJR and HYR at a ratio of 1:1. Immunohistochemical method was used to assess Bax and Bcl-2 protein levels in granulation tissue.
SJHYR 1 could accelerate wound healing as compared with SJHYR 2 and NS (P<0.05). On the third day in experiment, Bax and Bcl-2 proteins were not found in any groups, but on the seventh and eleventh day in experiment, Bax and Bcl-2 proteins in SJHYR 1-treated group were much higher than those in the other two groups (P<0.05).
SJR and HYR in different ratios may all have a role in regulating Bax and Bcl-2 expression in granulation tissue of diabetic rats during wound healing.
Journal of Chinese Integrative Medicine 11/2007; 5(6):661-4.
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ABSTRACT: In this paper, we propose to model the dynamics of BitTorrent (BT) P2P file sharing systems using the stochastic differential equation method. Unlike previous approach, our method can capture more realistic network environment and peers behavior. Closed-form solutions of various performance measures such as the average number of downloaders, seeders, the system throughput and file downloading time are derived. We also validate our mathematical results via simulation and show that not only our mathematical model can closely track the dynamics of BT-like systems, but the model has a much higher accuracy than previous proposed methods. Also, many important properties can be derived from the close-form solution such as performance scalability, sensitivity of the measurements to various system parameters. We believe the proposed method can provide better understanding in the design and analysis of BT-like P2P systems.
Communications, 2006. ICC '06. IEEE International Conference on; 07/2006
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ABSTRACT: To study the effects of Shengji Huayu Recipe (a traditional Chinese medicine compound recipe for resolving stagnation and promoting granulation) and its decomposed formulas (Huayu Recipe for resolving stagnation and Shengji Recipe for promoting granulation) on the synthesis of collagen types I and III in granulation tissue of rats in early wound healing.
Twenty-four male Sprague-Dawley (SD) rats with full-thickness skin lesion were randomized into 4 groups: Shengji Huayu Recipe-treated group, Shengji Recipe-treated group, Huayu Recipe-treated group and untreated group. Collagen types I and III in granulation tissue of the rats were tested with immunohistochemical methods and image analysis.
On the third day of wound healing, collagen I of the rats in both Shengji Huayu Recipe-treated group and Shengji Recipe-treated group was higher than that in the untreated group, and collagen I of the rats in Huayu Recipe-treated group was lower than that in the untreated group (P<0.05). Collagen III of the rats in the three treated groups were lower than that in the untreated group (P<0.05). On the seventh day of wound healing, Collagen I of the rats in both Shengji Huayu Recipe-treated group and Shengji Recipe-treated group was higher than that in the untreated group (P<0.05), and collagen III of the rats in both Shengji Recipe-treated group and Huayu Recipe-treated group was higher than that in the untreated group (P<0.05).
Resolving stagnation and promoting granulation therapy can promote the wound healing in rats.
Journal of Chinese Integrative Medicine 06/2005; 3(3):216-9.
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ABSTRACT: To observe the clinical effect of escin on patients with cutaneous pruritus caused by blood stasis and wind-dryness and to prove the theory that "wind should be treated by regulating blood disorder, and wind disappears after activating blood" in traditional Chinese medicine (TCM).
Fifty-one patients were randomly divided into escin-treated group (n=30) and loratadine-treated group (n=21). The patients in the escin-treated group were treated with escin for 4 weeks (300 mg, b.i.d.), and the patients in the loratadine-treated group were treated with loratadine (10 mg, q.d.). Symptom score reducing index (SSRI) was used to assess the pruritus degree, lesion range and lesion shape before the treatment, 2 weeks and 4 weeks after the treatment, respectively.
Two weeks after the treatment, the effective rate of the escin-treated group was 63.3%, and the effective rate of the loratadine-treated group was 67.0%. Four weeks after the treatment, the effective rates were 86.7% and 80.0% in escin- and loratadine-treated groups respectively. There was no statistical difference in total scores of SSRI in two groups (P>0.05), and the scores of pruritus degree and lesion shape also had no statistical difference (P>0.05), while the score of lesion range of the escin-treated group was lower than that of the loratadine-treated group (P<0.05).
Escin has satisfactory effect in treating pruritus caused by blood stasis and wind-dryness. The study confirms the TCM theory that "wind should be treated by regulating blood disorder, and wind disappears after activating blood".
Journal of Chinese Integrative Medicine 11/2004; 2(6):426-8.
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ABSTRACT: A scratch-resistant improvement of sol-gel derived nano-porous silica films by a base/acid two-step catalysis is reported. The silica films were prepared with the two-step catalytic sol-gel process and a dip-coating method, and then post annealed in air and a mixed gas atmosphere. The films were characterized with FE-SEM, AFM, TEM, XPS, FTIR, an ellipsometer, and an abrasion test. With the post annealing, the frequency shift of the FTIR absorption ω4(TO3) peak of the films to a lower wavenumber results from a decrease in the average Si-O-Si bridging angle. An increase in the full-width at half-maximum of the ω4 peak is ascribed to a wide distribution of the bridging angle because of formation of strained Si-O-Si bonds caused by the post annealing. XPS analysis shows that the effect of the mixed gas annealing on the binding energy and full-width at half-maximum (FWHM) for Si (2p) and O (1s) peaks is attributed to the further condensation reaction of the films resulting from the disappearance of the OH groups. The abrasion and adhesion tests indicate that the two-step catalysis obviously improves the scratch resistance and adhesion of the films, and that the mixed gas treatment further strengthens the silica network. The increase in strength is attributed to more Si-O-Si bond cross-linkages between silica particles formed by the two-step catalysis and the mixed gas treatment.
Journal of Physics D Applied Physics 04/2001; 34(9):1301. · 2.54 Impact Factor
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ABSTRACT: Scratch-resistance of sol-gel derived nano porous silica films were studied. The thin films were prepared with a dip-coating method from both one-step and two-step catalyzed silica sols, and treated in a mixture gas of ammonia and water vapour afterwards. The thin films were characterized by using Atomic Force Microscope (AFM), ellipsometer, Fourier-transform Infrared Spectroscope (FTIR), respectively. Experimental results have shown that the two-step catalysis remarkably improves strength of the films, and abrasion-resistance and adhesion of the silica films were further increased after the mixture gas treatment. It is attributed to the cross-linking of silica particles in the sols by randomly branched or/and entangled linear chains and more Si–O–Si bonds formed by the mixture gas treatment.
Journal of Sol-Gel Science and Technology 07/2000; 18(3):219-224. · 1.63 Impact Factor
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ABSTRACT: File swarming (or file sharing) is one of the most important applications in P2P networks. In this paper, we propose a stochastic framework to analyze a file-swarming system under realistic setting: constraints in upload/download capacity, collaboration among peers and incentive for chunk exchange. We first extend the results in the coupon system [L. Massoulie, M. Vojnovic, Coupon replication systems, in: Proc. ACM SIGMETRICS, Banff, Alberta, Canada, 2005] by providing a tighter performance bound. Then we generalize the coupon system by considering peers with limited upload and download capacity. We illustrate the last-piece problem and show the effectiveness of using forward error-correction (FEC) code and/or multiple requests to improve the performance. Lastly, we propose a framework to analyze an incentive-based file-swarming system. The stochastic framework we propose can serve as a basis for other researchers to analyze and design more advanced features of file-swarming systems.
Performance Evaluation.
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ABSTRACT: We report a polythiophene/fullerene (C60) bulk heterojunction solar cell fabricated via electrochemical co-deposition of polythiophene (PTh) and fullerene on an indium tin oxide (ITO) glass electrode modified with a thin layer of poly (3,4-ethylenedioxylthiophene) (PEDOT). Although the amount of C60 incorporated into the film was relatively low, the photovoltaic performance of the cell based on the polythiophene/fullerene (PTh/C60) composite film was remarkably improved.
Solar Energy Materials and Solar Cells.
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ABSTRACT: Wireless networks contain an inherent distributed spatial diversity that can be exploited by relays. Relay networks can take advantage of the broadcast-oriented nature of wireless transmission, but require more radio resource to transmit data for their multi-hop traits. Fortunately, incremental relaying technique, which can choose direct or multi-hop transmission adaptively, can efficiently utilize resource. In this article, the incremental transmission with amplify-and-forward (AF) relays is focused on. A practical hybrid-automatic retransmission request (HARQ) protocol is designed, and the related optimal relay selection strategy is proposed. To analyze the cooperative diversity of system with the proposed protocol, the capacity lower bound is deduced. Simulation and analytical results indicate that by adopting the optimal relay selection strategy, the system with the proposed HARQ protocol can achieve an order of cooperative diversity that equals the aggregated number of the relay and source nodes.
The Journal of China Universities of Posts and Telecommunications.
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ABSTRACT: The performance of heterojunction organic solar cells is critically dependent on the morphology of the donor and acceptor components in the active film. We report results of photovoltaic devices consisting of bilayers and bulk heterojunctions using poly(3-hexylthiophene) (P3HT) and Buckminsterfullerene C60. White light power efficiencies of η∼2.2% (bulk heterojunction) and 2.6% (bilayer) were measured after a thermal annealing step on completed devices. Optical and structural investigations on non-annealed bilayer thin films indicated a distinct porosity of the spin-coated polymer, which allows C60 to penetrate the P3HT layer and to touch the anode. This resulted for these bilayer solar cells in the experimental observation that electrons were collected predominantly at the cathode after photo-excitation of P3HT, but predominantly at the anode after C60 excitation. A morphological model to explain the ambipolar charge collection phenomenon is proposed.
Solar Energy Materials and Solar Cells.
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ABSTRACT: To control structure of nano-porous silica films effectively, a base/acid two-step catalytic sol-gel process was investigated. The nano-porous structure and IR absorption of the thin films were characterized by means of FE-SEM, AFM, SEM, FTIR, and ellipsometry, respectively. The experimental results have shown that the base/acid two-step catalysis can adjust the refractive index of the films from 1.18 to 1.41 rapidly and continuously. With a change of the experimental conditions, the frequency shift of the ω4 (TO3) peak of FTIR absorption to a lower wave number indicates a decrease in the average Si-O-Si bridging angle. A reduction of FWHM of the ω4 peak reveals a narrow distribution of the Si-O-Si bridging angle. These results suggest that influence of the experimental conditions on the FTIR absorption of the nano-porous silica films is attributed to a change of silica particle shape and state of aggregation of the particles in the films.
Materials Research Bulletin.
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ABSTRACT: A relatively new method to adjust refractive index of nano-porous silica films rapidly and continuously is reported. The thin films were prepared with the base/acid two-step catalytic sol-gel process and the dip-coating method. The structure, reflective spectra and refractive index of the films were analyzed with TEM, AFM, SEM, spectrophotometer, and ellipsometery, respectively. The experimental results have shown that the base/acid two-step catalysis can adjust the refractive index of the nano-porous silica films from 1.18 to 1.42 rapidly and continuously. And a broadband antireflective coating made with the method has very low reflectance. The average reflectance of the coated glass in the solar energy spectrum decreases to 1.5% from ∼7% of the glass.
Materials Science and Engineering: B.
