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The Rieske 2Fe-2S protein is a distinguishing subunit of the photosynthetic electron transport cytochrome b6f complex in chloroplast and cyanobacterial thylakoid membranes. We have constructed plasmids for overproduction in Escherichia coli of fusion, full-length, and truncated forms of the Rieske (PetC) protein from the cyanobacterium Nostoc sp. PCC 7906. A glutathione S-transferase/Rieske fusion protein was used to prepare specific chicken egg-yolk antibodies against the Rieske protein. Expression of the nonfusion petC gene in a T7 RNA polymerase promoter vector produced copious quantities of the full-length Rieske protein predominantly as inclusion bodies. The highly enriched, Rieske protein from inclusion bodies has been denatured in guanidine hydrochloride and refolded and the characteristic 2Fe-2S cluster reconstituted in vitro by incubation with iron and sulfide under reducing conditions. Purification by chromatography on Whatman DE52 cellulose and ultrafiltration through a 30000 molecular weight cutoff membrane yielded pure and predominantly monomeric Rieske protein. Reconstituted Rieske preparations showed intense and highly characteristic gx = 1.74, gy = 1.89, and gz = 2.03 "Rieske-type" electron paramagnetic resonance signals at 15 K. Two methods of reconstitution yielded Rieske preparations in which 20-60% of the protein contained 2Fe-2S clusters as determined by EPR spin quantitation. The reconstituted Rieske protein was soluble and stable at 4 degrees C in buffers containing nonionic detergents and showed a redox midpoint potential of +321 mV at pH 7.0 as determined by optical circular dichroism (CD) spectroscopy. These data demonstrate the in vitro restoration of a Cys and His liganded 2Fe-2S cluster and provide the basis for mutational and structural analysis of a PetC Rieske protein of oxygenic photosynthesis.

In this Chapter, we will discuss that in order to find the value of an American style derivative, what kind of mathematical problems needs to be solved. When we have such discussions, we mainly take American options as examples. However the methods can be used for other American style derivatives.

In this chapter, we discuss the implicit ABCs for the exterior problem of 2-D and 3-D Poisson equations, the Helmholtz equation, and the Navier system, and for the wave equation on unbounded domains. By using artificial boundaries, the original problems are reduced to boundary or initial boundary value problems on bounded computational domains. Implicit boundary conditions on the artificial boundaries are obtained, and then the finite element or finite difference method is applied to solve the reduced problems. Some error estimates are also given.

In this chapter, we discuss the application of ABCs for some problems with singularity, including the modified Helmholtz equation with singularity, the interface problem, the linear elastic system with singularity, and the Stokes equations with singularity. By using artificial boundaries, the singular points are removed, and the original problems are reduced to boundary value problems on computational domains. Boundary conditions on the artificial boundaries are obtained, and then the finite element method is applied to solve the reduced problems. Some error estimates are also given.

In this chapter, we discuss the discrete ABCs for the exterior problem of 2-D Poisson equation, 2-D Navier-Stokes equations, and 2-D linear elastic system, and for the 1-D Klein-Gordon equation on unbounded domains. By using artificial boundaries, the original problems are reduced to boundary or initial boundary value problems on bounded computational domains. Discrete boundary conditions on the artificial boundaries are obtained, and then the finite element or finite difference method is applied to solve the reduced problems.

In this chapter, we discuss the local ABCs for the exterior problem of 2-D and 3-D Poisson equations, and for the wave equations on unbounded domains. By using artificial boundaries, the original problems are reduced to boundary or initial boundary value problems on bounded computational domains. Local boundary conditions on the artificial boundaries are obtained. Some error estimates are also given.

This chapter is devoted to interest rate derivatives. Interest rate derivatives are financial products derived from interest rates. There are various interest rates that will be mentioned in this chapter. Here we first give the meaning of each interest rate and derive some relations among them.

In this chapter, we discuss the ABCs for wave equations, Klein- Gordon equations, and linear KDV equation on unbounded domains. By using artificial boundaries, the original problems are reduced to initial boundary value problems on bounded computational domains. Absorbing boundary conditions on the artificial boundaries are obtained, and then the finite difference method is applied to solve the reduced problems. Some stability results are also given.

In this chapter, we discuss the global ABCs for heat and Schrodinger equations on unbounded domains. By using artificial boundaries, the original problems are reduced to initial boundary value problems on bounded computational domains. Boundary conditions on the artificial boundaries are obtained, and then the finite difference method is applied to solve the reduced problems. Stability and error estimates are also discussed.

As we know, a problem of pricing an American-style derivative can be formulated as a linear complementarity problem, and for most cases, it can also be written as a free-boundary problem. In Chap. 8, we have discussed how to solve a linear complementarity problem. Here, we study how to solve a free-boundary problem numerically. Many derivative security problems have a final condition with discontinuous derivatives at some point. In this case, their solutions are not very smooth in the domain near this point, and their numerical solutions will have relatively large error. In Chap. 8, we have suggested to deal with this problem in the following way: instead of calculating the price of the derivative security, a difference between the price and an expression with the same or almost the same weak singularity is solved numerically. Because the difference is smooth, the error of numerical solution will be smaller. This method can still be used for free-boundary problems. For them there is another problem. On one side of the free boundary, the price of an American-style derivative satisfies a partial differential equation, and on the other side, it is equal to a given function. Because of this, the second derivative of the price is usually discontinuous on the free boundary. If we can follow the free boundary and use the partial differential equation only on the domain where the equation holds, then we can have less error. Hence, in Sect.9.1 we not only discuss how to separate the weak singularity caused by the discontinuous first derivative at expiry but also describe how to convert a free-boundary problem into a problem defined on a rectangular domain so that we can easily use the partial differential equation only on the domain where the equation holds. The method described in Sect.9.1 is referred to as the singularity-separating method (SSM) for free-boundary problems. The next two sections are devoted to discussing how to solve this problem using implicit schemes and pseudo-spectral methods for one-dimensional and two-dimensional cases. There, we also give some results on American vanilla, barrier, Asian, and lookback options, two-factor American vanilla options, and two-factor convertible bonds.

In this chapter, we discuss the global ABCs for the exterior problem of 2-D and 3-D Poisson equation, the modified Helmholtz equation, and the Helmholtz equation. By using artificial boundaries, the original problems are reduced to boundary value problems on bounded computational domains. Boundary conditions on the artificial boundaries are obtained, and then the finite element method is applied to solve the reduced problems. Some error estimates are also given.

This chapter is devoted to the basic numerical methods. We first discuss various approximations, solution of systems, and eigenvalue problems. Then, we describe how to determine the parameters in stochastic models.

As examples, in Figs.1.1–1.7 we showed how the prices of assets vary with time t. Figure 2.1 shows the stock price of Microsoft Inc. in the period March 30, 1999, to June 8, 2000. From these figures, we can see the following: the graphs are jagged, and the size of the jags changes all the time. This means that we cannot express S as a smooth function of t, and it is difficult to predict exactly the price at time t from the price before time t. It is natural to think of the price at time t as a random variable. Now let us give a model for such a random variable.

As pointed out in Sect. 2.3, when the short-term interest rate is considered as a random variable, there is an unknown function λ(r, t), called the market price of risk, in the governing equation.

Evaluation of European-style derivatives can be reduced to solving initial value or initial-boundary value problems of parabolic partial differential equations. This chapter discusses numerical methods for such problems. If an American option problem is formulated as a linear complementarity problem, then the only difference between solving a European option and an American option is that if the solution obtained by the partial differential equation does not satisfy the constraint at some point, then the solution of the PDE at the point should be replaced by the value determined from the constraint condition. Such methods are usually referred to as projected methods for American-style derivatives. Therefore, the two methods are very close, and we also study the projected methods in this chapter.

In this chapter, we discuss the nonlinear ABCs for Burgers equation, Kardar-Parisi-Zhang equation, and Schrodinger equation on unbounded domains. By using artificial boundaries, the original problems are reduced to initial boundary value problems on bounded computational domains. Nonlinear boundary conditions on the artificial boundaries are obtained, and then the finite difference method is applied to solve the reduced problems. Some stability results are also given.

Part I: Partial Differential Equations in Finance: Introduction Basic Options Exotic Options Interest Rate Derivative Securities.- Part II: Numerical Methods for Derivative Securities: Basic Numerical Methods Initial-Boundary Value and LC Problems Free Boundary Problems Interest Rate Modeling.- References.- Index.

In this chapter, we discuss the global ABCs for the exterior problem of 2-D and 3-D Navier system, and 2-D Stokes system. By using artificial boundaries, the original problems are reduced to boundary value problems on bounded computational domains. Boundary conditions on the artificial boundaries are obtained, and then the finite element method is applied to solve the reduced problems. Some error estimates are also given.

In this chapter, we deal with finite-difference methods for parabolic partial differential equations, including algorithms, stability and convergence analysis, and extrapolation techniques of numerical solutions.

Pigging is one of the basic measures used to guarantee long-term pipeline safety during transmission, and is often used after pressure testing and in normal working conditions. In China most of the natural gas pipelines are distributed in hills, mountains and other large areas, but terrain height has no effect. Due to the pipeline stress factors on pipe walls thought to be related to the cleaning process involved in the gas pipeline stress model, this paper offers an appropriate pigging transient model in order to simulate the stress on pipeline walls more accurately, analyze the effects of pigging for gas transmission pipeline quantitatively and offer guidance in the furtherance of pigging operation knowledge.

At present the gas transmission pipeline stress analysis is mainly aimed at ordinary buried pipe. Stress analysis is less for gas pipeline in tunnels, especially on the pressure testing condition. Usually testing pressure is greater than working pressure. It is necessary to know the stress distribution of passing-through gas pipeline on pressure testing condition. This paper established pipe stress analysis model for XX gas transmission pipeline in shaft of shield tunnel on pressure testing condition by CAESAR II software. This paper obtained the gas pipe stress distribution, clearly determined the stress key points, and checked the strength of the pipeline. This method provides guidance for gas pipeline stress analysis.

Tubular epithelial loss has been shown to be responsible for the formation of atubular glomeruli leading to nephron decomposition and interstitial fibrosis in obstructive uropathy. Cells undergoing apoptosis and autophagic cell death play an important role in this process, yet the mechanisms are not fully understood. In this study, we aimed to investigate whether autophagy cooperating with apoptosis is associated with mitochondrial damage and whether oxidative stress plays an important role in the loss of tubular epithelium following unilateral ureteral obstruction. In this model, we demonstrated that there is coexistence of autophagy and apoptosis with tubular atrophy in obstructed proximal tubules. After unilateral ureteral obstruction (UUO), autophagy in proximal tubular cells was enhanced steadily up to 7 days in the obstructed kidney and declined thereafter, while apoptosis was induced in a time-dependent manner from 3 to 14 days. Mitochondrial structure and number also changed during UUO. Lipid peroxidation products, NOX4, and NADPH oxidase activity were also increased in the obstructed renal cortex, and peaked at 7 days. In vitro, we showed that H2O2 induced mitochondrial injury leading to autophagy and apoptosis through the Beclin 1 pathway and interference with Bcl-2 expression. Thus, our data demonstrate that oxidative stress leading to mitochondrial damage and driven autophagy-dependent cell death and apoptosis are important mechanisms of tubular decomposition in obstructive nephropathy.

To investigate the relationship between nutritional status and acute radiotoxicity of patients with head and neck cancer.Nutritional status and acute radiotoxicities of 130 head and neck cancer patients were prospectively surveyed during the 4th week of radiotherapy. Relationships between nutritional status and acute radiotoxicities were analyzed by canonical correlation.The first canonical correlation coefficient was 0.653, statistically significant, which showed that some negative relationships were found between nutritional status (such as serum prealbumin, transferring, lymphocytes, lymphocyte percentage) and acute radiotoxicities (such as dry mouth, throat/sore throat, fatigue, radiation dermatitis) of head and neck cancer patients.When the detection value of serum prealbumin, transferrin, lymphocytes, lymphocyte percentage was below the normal, the appropriate nutritional support would be given to improve immunity and to relieve the acute radiotoxicitoes.

This paper describes the geographic information system (GIS) concepts, basic principles and the status of research and application at home and abroad. The paper proposed the specific functions of GIS application in the gas pipeline: the search query, data processing, spatial analysis, cartographic output, business analysis, system maintenance of all kinds of underground gas pipeline. Thereby increasing the efficiency and effectiveness of the gas company, the positioning of the place of an sudden event and the occurrence of disasters in time, and to propose effective solutions to minimize the accident loss. Finally, the GIS accident analysis module was introduced and applied in gas network leakage analysis. That provides the basis for the gas consequences and reduces the accident loss.

Recently, the perforation leakage accidents of gas pipeline which are caused by corrosion occur frequently and bring great economic losses. It is particularly important to located the leakage of the buried gas pipeline in order to take measures to reduce the potential unsafe factors immediately and nip in the bud. In this article, the constraint space model of geological environment where buried gas pipeline located was first constructed and implemented a three-dimensional testing and real-time monitoring and are then referenced to the back-calculation methods of the sources intensity theory to accurately predict or determine the leakage point and improve the pipeline operating efficiency.

Most of China's natural gas pipeline passed through a variety of geological environment. The pipeline accidents happen frequently and are caused by landslides and collapse. The reliability of the current research on mountain pipe buried natural gas pipeline is limited to defects, almost empty, and on the judgment of the hazard is confined to the traditional reliability evaluation method. This paper uses D-S evidence theory to the mountain pipe for reliability analysis, references fuzzy data theory, establishes the model of geological disasters in natural gas pipeline, deals with the inconsistency for the same evaluation objects, makes evaluation and has more unity, and avoids the expertise and experience of the one-sided and subjective judgments resulting in bias.

The heavy oil, of Fengcheng Oilfield in Xinjiang, is a typical oil which is mainly composed of resin and asphaltene. Because of its high viscosity, density and poor mobility, the heavy oil has to be transferred by pipeline after mixed light oil and heated. This paper states the research on the pipeline transportation technology of heavy oil of Fengcheng Oilfield and proposes six transmission solutions. From the viewpoint of economy, safety and reliability, and by contrast, the optimal solutions of the pipeline material selection, the pipeline design pressure, operating pressure, station distance, the pipeline diameter, in-station temperature and out-station temperature are determined.

Background It has been reported that ischemic postconditioning (IPO) or mesenchymal stem cell (MSC) engraftment could protect organs from ischemia/reperfusion (I/R) injury. We investigated the synergetic effects of combined treatment on lung injury induced by I/R. Methods Adult Sprague-Dawley rats were randomly assigned to one of the following groups: sham-operated control, I/R, IPO, MSC engraftment, and IPO plus MSC engraftment. Lung injury was assessed by arterial blood gas analysis, the wet/dry lung weight ratio, superoxide dismutase level, malondialdehyde content, myeloperoxidase activity, and tissue histologic changes. Cytokine expression was detected using real-time polymerase chain reaction, Western blotting, and enzyme-linked immunosorbent assay. Cell apoptosis was determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end assay and annexin V staining. Results MSC engraftment or IPO alone markedly attenuated the lung wet/dry weight ratio, malondialdehyde and myeloperoxidase production, and lung pathologic injury and enhanced arterial partial oxygen pressure, superoxide dismutase content, inhibited pro-inflammatory cytokine levels, and decreased cell apoptosis in lung tissue, compared with the I/R group. In contrast, IPO pretreatment enhanced the protective effects of MSC on I/R-induced lung injury compared with treatment alone. Moreover, in the combined treatment group, the number of MSC engraftments in the lung tissue was increased, associated with enhanced survival of MSCs compared with MSC treatment alone. Additional investigation showed that IPO treatment increased expression of vascular endothelial growth factor and stromal cell-derived factor-1 in I/R lung tissue. Conclusions IPO might contribute to the homing and survival of transplanted MSCs and enhance their therapeutic effects through improvement of the microenvironment of I/R injury.

The numerical solution of the nonlinear wave equation on unbounded spatial domain is considered. The artificial boundary method is introduced to reduce the nonlinear problem on unbounded spatial domain to an initial boundary value problem on a bounded domain. Using the unified approach, which is based on the operator splitting method, we construct the efficient nonlinear local absorbing boundary conditions for the nonlinear wave equation, and give the stability analysis of the resulting boundary conditions. Finally, several numerical examples are given to demonstrate the effectiveness of our method.

A novel three level linearized difference scheme is proposed for the semilinear parabolic equation with nonlinear absorbing boundary conditions. The solution of this problem will blow up in finite time. Hence this difference scheme is coupled with an adaptive time step size, i.e., when the solution tends to infinity, the time step size will be smaller and smaller. Furthermore, the solvability, stability and convergence of the difference scheme are proved by the energy method. Numerical experiments are also given to demonstrate the theoretical second order convergence both in time and in space in L ∞ -norm.

Evolving cooperation by evolutionary algorithms is impossible without introducing extra mechanisms. Group selection theory in biology is a good candidate as it explains the evolution of cooperation in nature. Two biological models, Wilson's trait group selection model and Traulsen's group selection model are investigated and compared in evolutionary computation. Three evolutionary algorithms were designed and tested on an n-player prisoner's dilemma problem; two EAs implement the original Wilson and Traulsen models respectively, and one EA extends Traulsen's model. Experimental results show that the latter model introduces high between-group variance, leading to more robustness than the other two in response to parameter changes such as group size, the fraction of cooperators and selection pressure.

A large proportion of interstitial fibroblasts actually originate from tubular epithelial cells via the epithelial-to-mesenchymal transition (EMT) in renal fibrogenesis. Transforming growth factor-beta1 (TGF-beta1) is capable of initiating and completing the entire EMT course. Bone morphogenetic protein-7 (BMP-7) is a member of the TGF-beta superfamily. Recent studies indicate that BMP-7 could reverse established renal fibrosis in mice, primarily through counteracting TGF-beta1-mediated EMT. Therefore, we tested the hypothesis that BMP-7 functions by antagonizing profibrogenic events that are induced by TGF-beta1 in cultured human renal proximal tubular epithelial (HK-2) cells.Cultured HK-2 cells were treated with TGF-beta1 (3 ng/mL) or a combination of TGF-beta1 and BMP-7 (100-400 ng/mL) for 48 hours. Morphological changes were assessed by phase contrast microscopy. The expression of alpha-smooth muscle actin (alpha-SMA), E-cadherin, fibronectin, collagen I and connective tissue growth factor (CTGF) was analyzed by immunofluorescence, reverse transcriptase polymerase chain reaction and Western blotting.Incubation of HK-2 cells with 3 ng/mL TGF-beta1 for 48 hours induced EMT, in association with decreased E-cadherin expression, increased alpha-SMA, fibronectin, collagen I and CTGF expression, and loss of epithelial morphology. BMP-7 inhibited all these effects in a dose-dependent manner. In addition, 200 ng/mL BMP-7 reversed TGF-beta1-induced EMT, in association with reexpression of endogenous E-cadherin.These data suggest that BMP-7 attenuates progressive loss of kidney function and renal fibrosis through counteracting TGF-beta1-mediated EMT.

Aims: The nephrotoxic side effects of cyclosporine A (CsA) are partly due to induction of the epithelial-to-mesenchymal transition (EMT), possibly through upregulation of connective tissue growth factor (CTGF). Bone morphogenetic protein (BMP-7) has been reported to protect against and reverse renal injury via its renotropic and antifibrotic effects. We therefore designed a method to investigate the mechanism by which BMP-7 inhibits CSA-induced EMT in cultured human renal proximal tubular epithelial (HK-2) cells and whether BMP-7 can antagonize CsA-induced profibrogenic effects. Methods: Cultured HK-2 cells were treated with CsA or a combination of CsA and BMP-7 for 72 h. Morphological changes were assessed by phase-contrast microscopy. The expression of α-smooth muscle actin (α-SMA), E-cadherin, collagen type I and CTGF was analyzed by immunofluorescence, RT-PCR, and Western blot. Additionally, the effect of CTGF silencing on CsA-mediated gene expression was assessed. Results: CsA-induced EMT was associated with decreased expression of E-cadherin, increased expression of α-SMA, collagen type I and CTGF, and loss of epithelial morphology. BMP-7 inhibited these effects in a dose-dependent manner. Using siRNA, CTGF knock-down also attenuated EMT-associated phenotypic changes induced by CsA. Conclusion: These data suggest that BMP-7 can block CsA-induced EMT by downregulating the expression of CTGF, a downstream mediator of EMT.

This paper aims to design local absorbing boundary conditions (LABCs) for the two-dimensional nonlinear Schrodinger equations on a rectangle by extending the unified approach. Based on the time-splitting idea, the main process of the unified approach is to approximate the kinetic energy part by a one-way equation, unite it with the potential energy equation, and then obtain the well-posed and accurate LABCs on the artificial boundaries. In the corners, we use the (1,1)-Pade approximation to the kinetic term and also unite it with the nonlinear term to give some local corner boundary conditions. Numerical tests are given to verify the stable and tractable advantages of the method.

An efficient method is proposed for numerical solutions of nonlinear Schr\"{o}dinger equations in an unbounded domain. Through approximating the kinetic energy term by a one-way equation and uniting it with the potential energy equation, absorbing boundary conditions are designed to truncate the unbounded domain, which are in nonlinear form and can perfectly absorb the waves outgoing from the truncated domain. We examine the stability of the induced initial boundary value problems defined on the computational domain with the boundary conditions by a normal mode analysis. Numerical examples are given to illustrate the stable and tractable advantages of the method., Comment: 17 pages, 6 figures, 40 conferences

This study was aimed at assessing physicians' and physician assistants' knowledge and attitudes toward HIV/AIDS and identifying determinants of willingness to care for infected individuals in Southeast China. From May to June 2004, 454 physicians and physician assistants from 5 different medical facility levels in Fujian Province, China, undertook a survey on knowledge, attitude, behavior, and practice (KABP). Only 40.4% (95% confidence intervals: 35.9, 44.9) were willing to provide healthcare services for people living with HIV/AIDS (PLWHAs). Knowledge (p0.001) and attitude scores (p = 0.01) as well as the proportion of those willing to provide care (p0.001) significantly differed by facility level. Multivariate analysis identified supportive attitudes toward PLWHAs (p0.001), self-confidence in providing care (p0.001), and facility level as significant predictors of willingness to care for infected individuals. Village medical stations showed the most unfavorable outcomes. Enhanced education as well as specific programs promoting supportive attitudes and willingness to care is therefore required, especially among those working at lower facility levels in remote areas.

We propose an adaptive approach in picking the wave-number parameter of absorbing boundary conditions for Schr\"{o}dinger-type equations. Based on the Gabor transform which captures local frequency information in the vicinity of artificial boundaries, the parameter is determined by an energy-weighted method and yields a quasi-optimal absorbing boundary conditions. It is shown that this approach can minimize reflected waves even when the wave function is composed of waves with different group velocities. We also extend the split local absorbing boundary (SLAB) method [Z. Xu and H. Han, {\it Phys. Rev. E}, 74(2006), pp. 037704] to problems in multidimensional nonlinear cases by coupling the adaptive approach. Numerical examples of nonlinear Schr\"{o}dinger equations in one- and two dimensions are presented to demonstrate the properties of the discussed absorbing boundary conditions., Comment: 18 pages; 12 figures. A short movie for the 2D NLS equation with absorbing boundary conditions can be downloaded at http://home.ustc.edu.cn/~xuzl/movie.avi. To appear in Journal of Computational Physics