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Search Results: 1 - 10 of 26082 matches for " Peng Shao "
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Uniform Sobolev Resolvent Estimates for the Laplace-Beltrami Operator on Compact Manifolds
Peng Shao,Xiaohua Yao
Mathematics , 2012,
Abstract: In this paper we continue the study on the resolvent estimates of the Laplace-Beltrami operator $\Delta_g$ on a compact manifolds $M$ with dimension $n\geq3$. On the Sobolev line $1/p-1/q=2/n$ we can prove that the resolvent $(\Delta_g+\zeta)^{-1}$ is uniformly bounded from $L^p$ to $L^q$ when $(p,q)$ are within the admissible range $p\leq2(n+1)/(n+3)$ and $q\geq2(n+1)/(n-1)$ and $\zeta$ is outside a parabola opening to the right and a small disk centered at the origin. This naturally generalizes the previous results in \cite{Kenig} and \cite{bssy} which addressed only the special case when $p=2n/(n+2), q=2n/(n-2)$. Using the shrinking spectral estimates between $L^p$ and $L^q$ we also show that when $(p,q)$ are within the interior of the admissible range, one can obtain a logarithmic improvement over the parabolic region for resolvent estimates on manifolds equipped with Riemannian metric of non-positive sectional curvature, and a power improvement depending on the exponent $(p,q)$ for flat torus. The latter therefore partially improves Shen's work in \cite{Shen} on the $L^p\to L^2$ uniform resolvent estimates on the torus. Similar to the case as proved in \cite{bssy} when $(p,q)=(2n/(n+2),2n/(n-2))$, the parabolic region is also optimal over the round sphere $S^n$ when $(p,q)$ are now in the admissible range. However, we may ask if the admissible range is sharp in the sense that it is the only possible range on the Sobolev line for which a compact manifold can have uniform resolvent estimate for $\zeta$ being ouside a parabola.
Metal Stenting with or without Endobiliary Radiofrequency Ablation for Unresectable Extrahepatic Cholangiocarcinoma  [PDF]
Huihong Liang, Zhenwei Peng, Liangqi Cao, Shikun Qian, Zili Shao
Journal of Cancer Therapy (JCT) , 2015, DOI: 10.4236/jct.2015.611106
Abstract: Background: Retrospective comparison of stent patency and survival of patients with unresectable extrahepatic cholangiocarcinoma (CCA) treated by placement of self-expanding metal stents (SEMS) with or without endobiliary radiofrequency ablation (ERFA). Methods: Between January 2010 and September 2014, 76 patients with biliary obstruction caused by unresectable extrahepatic CCA (27 patients with Bismuth type I hilar CCA and 49 patients with distal CCA) were recruited into this study. Patients either received ERFA with SEMS (n = 34) or SEMS only (n = 42). Stent patency and survival of both groups were compared and predictors for overall survival were analyzed. Results: Demographic data were not different between the two groups. Complication rates of both groups were similar. Thirty-day stent patency was obtained in all patients and the median stent patency in the ERFA + SEMS group (9.5 months, 4.5 - 14.0 months) was significantly longer than that in the SEMS group (8.4 months, 4.9 - 11 months) (P = 0.024). The overall survival curve in the ERFA + SEMS group was significantly better than that of the SEMS group (P = 0.036). Multivariate Cox proportional hazards regression analyses showed that ERFA, tumor AJCC stage, extrahepatic CCA type, serum albumin and adjuvant chemotherapy were significant prognostic factors for overall patient survival. Conclusions: ERFA is effective for unresectable extrahepatic CCA and may improve metal stent patency and patient survival for unresectable extrahepatic CCA with biliary obstruction. Prospective randomized trials will be needed to confirm these findings.
The ecological characteristics of Cryptocarya concinna population
黄果厚壳桂种群生态学特征

PENG Shao Lin,
彭少麟

生态学报 , 1999,
Abstract: Cryptocarya concinna is a dominant population in the zonal vegetation of south sub tropic evergreen forest.It appears in an extensive distribution in the low subtropical hills Cryptocarya concinna is a mesophytes which is early one to entry the succession community in a successional process.It has a higher photosynthesis rate,and it can develop rapidly when it got a fit site.The biomass and productivity of Cryptocarya concinna population are big in its community.It takes part in a very important position on the stability of the community structure and function.
Studies on edge effect of successional communities and restoration of forest fragmentation in low sub-tropics
南亚热带演替群落的边缘效应及其对森林片断化恢复的意义

PENG Shao Lin,
彭少麟

生态学报 , 2000,
Abstract: The dynamics of the ecotone of Pinus forest community and mixed forest community was studied with 16 years' permanent quadrat analysis and with comparing it to its adjacent communities. Species richness, diversity, organization level, leaf area index, biomass and productivity as well as comparative ordination and cluster techniques were used to analyze edge effect. The results showed that ecotonal community had developed into mixed forest, and it was near pine forest in the characteristics in 16 years ago. Its adjacent communities, pine forest and mixed forest had been their base states with some change in 16 years. The edge had moved over 100 m into pine forest. Time of edge affection lasted about 20 years in this type. The direction of edge effect was same as succession, and it speed up succession in ecotonal community more. It's a vary good case that edge effect is usefull for patch elimination after fragmentation.
Advances in Plant Population Viability Analysis
植物种群生存力分析研究进展

PENG Shao Lin,
彭少麟

生态学报 , 2002,
Abstract: Studies on plant population viability analysis(PVA) since 1990s have been reviewed in this paper, which discusses: factors affecting plant population viability; methods and steps of plant PVA; plant PVA models; and challenges to plant PVAs. In addition, the accuracy and effectiveness of plant PVAs in management or conservation strategies, as well as their limitations and future development have been discussed. The factors affecting plant population viability can be divided into stochastic factors and deterministic factors. Stochastic factors include environmental stochasticity, demographic stochasticity, genetic stochasticity and natural catastrophes. Environmental stochasticity is the most common stochastic factor being incorporated into plant PVA models. Demographic stochasticity and natural catastrophes have been simulated in some plant PVA models. Though genetic stochasticity rarely appears in PVA models, it is an important factor in long term. Different from animals, a plant population is always associated with certain type of community, and influenced by some deterministic factors such as interspecific competitions, herbivores, mutualisms. For endangered plant populations, the loss or deterioration of habitat can be a fatal deterministic factor, which is irreversible. Methods and steps of plant PVA have been summarized in this paper, based on published plant PVAs. First step is the assessment of population growth trajectories, and identification of life history stages. Life history stages of a population can be classified into seed, seedling, juvenile and adult. Second step is to record demographic parameters, and measure and estimate stochastic factors. In third step, a population dynamic model will be built on project matrices. Then, the model is parameterized with transition matrices. In following step, the correlation of parameters is analyzed, the effect of factors is examined, and the model is developed. Finally, the model is simulated on computer. Results will be persistence probability of population and minimum viable population at a given time. Stochastic simulation models, and metapopulation dynamics models have been found in plant PVAs. They are built on transition matrices, and different from animal Vortex model based on Monte Carlo simulations. The stochastic simulation model, incorporating stochastic factors, is often applied in a single population, and considered a valuable method. The metapopulation dynamics model, which is mainly used in populations with turnovers, has great potential for plant PVA. Some plant characters are different from those of animals. Unique plant characters include seed dormancy, diverse mating systems, periodic recruitment, clonal growth and so on. All these characters make it difficult to survey demographic parameters, which are indispensable for plant PVA. Besides predicting extinction time and extinction probability of a population over a given period, PVA has been applied in assessing the effect
Millimeter wave therapy for abdominal incision wound: A clinical study
Meena Pradhan, Yong Shao, Yun Peng Luo
Asian Journal of Medical Sciences , 2015, DOI: 10.3126/ajms.v6i1.10311
Abstract: Background: This case-control study, conducted in 2012, was performed to determine if MMWT, a non invasive therapeutic treatment modality, could reduce postoperative pain and infection in patients who had abdominal sections. Methods: The study group (30 patients) incision sites were exposed to MMWT within 24 hour of cesarean and the control group (90 patients) was not exposed to MMWT. Millimeter wave apparatus with intensity of 38 GHz and power flux output density of 40 mW/cm 2 was used for subjecting the cesarean incision site to MMWT. The first exposure to MMWT was done for 30 minutes within 24 hour of cesarean section. In total, they were exposed for 30 minutes daily for 3 days. Wound healing was assessed every day. Results: Pain intensity score in the exposure group reduced significantly compared to the control group. The mean pain intensity score of the study group on the 3rd postoperative day was 3.3±1.8 (95% CI 2.6-3.9) compared to 4.2±1.6 (95% CI 3.8-4.5) of the control group (P< 0.01). Pain reduction rate on day 3 was significantly higher than day 1 in the study group compared to the control group (P = 0.0024). Routine white blood cell (WBC) count was significantly lower in the MMWT treated patients (11.3±1.8×10 9 ; 95% CI 10.6-12) compared to the control group (12.3±2.9×10 9 ; 95% CI 11.7-12.9)(P<0.03). Conclusions: The results of our study verified that MMWT can relieve post operative pain, decrease post operative morbidities, enhance early mobilization, and can serve as an alternative tool to suppress pain and cure infection. DOI: http://dx.doi.org/10.3126/ajms.v6i1.10311 Asian Journal of Medical Sciences Vol.6(1) 2015 43-48
Cellular responding kinetics based on a model of gene regulatory networks under radiotherapy  [PDF]
Jin-Peng Qi, Yong-Sheng Ding, Shi-Huang Shao, Xian-Hui Zeng, Kuo-Chen Chou
Health (Health) , 2010, DOI: 10.4236/health.2010.22021
Abstract: Radiotherapy can cause DNA damage into cells, triggering the cell cycle arrest and cell apop-tosis through complicated interactions among vital genes and their signal pathways. In order to in-depth study the complicated cellular res- ponses under such a circumstance, a novel mo- del for P53 stress response networks is pro- posed. It can be successfully used to simulate the dynamic processes of DNA damage trans-ferring, ATM and ARF activation, regulations of P53-MDM2 feedback loop, as well as the toxins degradation. Particularly, it has become feasible to predict the outcomes of cellular response in fighting against genome stresses. Consequently, the new model has provided a reasonable framework for analyzing the complicated regu-lations of P53 stress response networks, as well as investigating the mechanisms of the cellular self-defense under radiotherapy.
Cryptanalysis of a Chaotic Communication Scheme Using Parameter Observer
Haipeng Peng,Yan Shao,Lixiang Li,Yixian Yang
Mathematical Problems in Engineering , 2010, DOI: 10.1155/2010/361860
Abstract: This paper addresses the cryptanalysis of a secure communication scheme proposed by Wu (2006), where the information signal is modulated into a system parameter of a unified chaotic system. It is demonstrated that a parameter observer can be designed to identify the parameter determined by the transmitted information and then the transmitted information can be obtained. Compared with the existing analysis using adaptive observer, the cryptanalysis based on parameter observer is much simpler and needs less structure information of the transmitter system. With numerical simulations, it is shown that the parameter observer has stronger practicality and robustness. Furthermore, it is still possible to obtain the transmitted information, even if the derivative of the transmitted signal is unknown.
An Approach to the Production of Soluble Protein from a Fungal Gene Encoding an Aggregation-Prone Xylanase in Escherichia coli
Yilin Le,Jingjing Peng,Huawei Wu,Jianzhong Sun,Weilan Shao
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0018489
Abstract: The development of new procedures and protocols that allow researchers to obtain recombinant proteins is of fundamental importance in the biotechnology field. A strategy was explored to overcome inclusion-body formation observed when expressing an aggregation-prone fungal xylanase in Escherichia coli. pHsh is an expression plasmid that uses a synthetic heat-shock (Hsh) promoter, in which gene expression is regulated by an alternative sigma factor (σ32). A derivative of pHsh was constructed by fusing a signal peptide to xynA2 gene to facilitate export of the recombinant protein to the periplasm. The xylanase was produced in a soluble form. Three factors were essential to achieving such soluble expression of the xylanase: 1) the target gene was under the control of the Hsh promoter, 2) the gene product was exported into the periplasm, and 3) gene expression was induced by a temperature upshift. For the first time we report the expression of periplasmic proteins under the control of an Hsh promoter regulated by σ32. One unique feature of this approach was that over 200 copies of the Hsh promoter in an E. coli cell significantly increased the concentration of σ32. The growth inhibition of the recombinant cells corresponded to an increase in the levels of soluble periplasmic protein. Therefore, an alternative protocol was designed to induce gene expression from pHsh-ex to obtain high levels of active soluble enzymes.
Some key points of restoration ecology
恢复生态学焦点问题

PENG Shao-Lin,
彭少麟

生态学报 , 2003,
Abstract: Five key points of restoration ecology was discussed in this paper, which are the concept of restoration ecology, the current trends of restoration ecology, the application of traditional ecology theory in the practice of ecological restoration and the social characteristic of restoration ecology. Restoration ecology still has no general definition, as a young subject. There are mainly three schools about it. The fist school emphasizes that the degraded ecosystem should be restored into ideal state. The se...
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