bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrochemical evaluation of Ti‐13Nb‐13Zr, Ti‐6Al‐4V and Ti‐6Al‐7Nb alloys for biomedical application by long‐term immersion tests
Authors: Assis S. L. , Costa I. 
Published: May 2007

AbstractIn this investigation the electrochemical behaviour of the Ti‐13Nb‐13Zr, Ti‐6Al‐4V and Ti‐6Al‐7Nb alloys, for application as implant materials was evaluated in Hanks' solution by electrochemical techniques. The alloys were immersed in this solution for 410 days and periodically they were tested by electrochemical impedance spectroscopy. At the end of this period, polarization curves of the three titanium alloys were obtained. The electrochemical impedance experimental results were interpreted using an equivalent electrical circuit that simulates a duplex structure oxide composed of an inner compact layer, here called barrier layer, and an outer and porous layer. The results indicated that all the alloys present a very high corrosion resistance in the electrolyte used, typical of passive alloys, and that the corrosion resistance is mainly due to the barrier layer. The passive like behaviour was maintained during the whole period of test.
Corrosion resistance of steel with hot‐dipped galvanized zinc and zinc alloy coatings in seawater
Authors: Li Y. , Liu J. , Zhang J. , Chu S. 
Published: May 2007

AbstractHot‐dipped galvanized zinc and zinc alloy coatings were used as protective metallic coatings for steel structures in seawater in China. Corrosion of the two coatings immersed in sea water in Qingdao and Xiamen for 6 years were introduced and analyzed, which provides a basis for further development and applications of these coatings in China. Tests proved that the anti‐corrosion performance of the hot‐dipped low alloy zinc coatings (aluminum content less than or equal to 10 wt%) is equal to or even lower than that of the pure zinc sheet, while the performance of the hot‐dipped high alloy zinc coatings is higher than that of the pure zinc sheet. The hot‐dipped high alloy zinc coatings can be further developed for optimal performance in the future.
Gel Point Investigation of a Chitosan System Using Fourier Transform Rheometry and Multi‐Frequency Excitation
Authors: Cho Jaepyoung , Heuzey Marie‐Claude , Hamdine Mélina 
Published: May 2007

AbstractIn this study, the sol‐gel transition temperature of a thermosensitive chitosan system was measured using SAOS, in‐real time FTR and multi‐frequency SAOS excitation. From FT analysis, we found that the intensity of the harmonics stayed constant while the chitosan system remained in the solution state, while it increased passed the gelation point. Multi‐frequency SAOS excitation was also carried out using a summation function of sine waves that allowed performing the measurements in the LVR. This last technique could determine the unique (frequency independent) critical sol‐gel transition temperature, and was found to be less tedious than the application of the traditional Chambon and Winter's method.magnified image
Pulse doppler and M‐mode to assess viability of cardiac allografts using heterotopic femoral heart transplantation in rats
Authors: Gordon Chad R. , Lefebvre Daniel R. , Matthews Martha S. , Strande Louise F. , Marra Steven W. , Guglielmi Massimiliano , Skaf Jad , Hollenberg Steven M. , Hewitt Charles W. 
Published: May 2007

AbstractNoninvasive assessment of heterotopic heart transplants using Doppler echocardiography was first described in two patients by Allen at Stanford in 1981. Since then, numerous experiments studying heterotopic heart transplantation in humans and large animals have confirmed its utility by employing either an intra‐abdominal or cervical model. In rats, however, prior research investigating intra‐abdominal heterotopic hearts has showed echocardiography to be ineffective. We have recently developed a new technique for heterotopic femoral heart transplantation in rats, which employs the novel use of trans‐femoral echocardiography. Therefore, our goal was to re‐examine the efficacy of echocardiography for detection of graft rejection. © 2007 Wiley‐Liss, Inc. Microsurgery, 2007.
On the solutions of the linear integral equations of Volterra type
Authors: Özdemir İsmet , Temizer Ö. Faruk 
Published: May 2007

AbstractSome boundaries about the solution of the linear Volterra integral equations of the form f(t)=1−K*f were obtained as |f(t)|⩽1, |f(t)|⩽2 and |f(t)|⩽4 in (J. Math. Anal. Appl. 1978; 64:381–397; Int. J. Math. Math. Sci. 1982; 5(1):123–131). The boundary of the solution function of an equation in this type was found as |f(t)|⩽2n in (Integr. Equ. Oper. Theory 2002; 43:466–479), where t∈[0, ∞) and n is a natural number such that n⩾2. In (Math. Comp. 2006; 75:1175–1199), it is shown that the boundary of the solution function of an equation in the same form can also be derived as that of (Integr. Equ. Oper. Theory 2002; 43:466–479) under different conditions than those of (Integr. Equ. Oper. Theory 2002; 43:466–479).In the present paper, the sufficient conditions for the boundedness of functions f, f′, f′′, …, f(n+3), (n∈ℕ) defined on the infinite interval [0, ∞) are given by our method, where f is the solution of the equation f(t)=1−K*f. Copyright © 2007 John Wiley & Sons, Ltd.
Berry phytochemicals, genomic stability and cancer: Evidence for chemoprotection at several stages in the carcinogenic process
Authors: Duthie Susan J. 
Published: May 2007

AbstractConsumption of a diet high in plant‐based foods is associated with a decreased risk of epithelial cell cancers at several sites. Cytoprotectants in fruits and vegetables include vitamins, minerals and numerous micronutrients. While there is little evidence uniquely linking berry consumption with lower cancer risk, berries contain high levels of compounds believed to reduce malignant transformation, including the polyphenol flavonoids and anthocyanins. There is strong and convincing evidence that berry extracts and berry phytochemicals modulate biomarkers of DNA damage and indicators of malignant transformation in vitro and in vivo. Data from numerous cell culture and animal models indicate that berry components such as the anthocyanins are potent anticarcinogenic agents and are protective against genomic instability at several sites in the carcinogenic pathway. Anticarcinogenic mechanisms include modulation of carcinogen activation and detoxification, decreased DNA binding of the carcinogen, inhibition of oxidative DNA damage, alteration in cell signalling and malignant transformation and inhibition of cell invasiveness and metastasis. Exactly which berry constituents are cytoprotective remains uncertain and in the majority of in vitro and in vivo studies the concentration of extract or phytochemical employed is non‐nutritional. Evidence for an anticarcinogenic effect in human studies is weak.
Cranberry cocktail juice, cranberry concentrates, and proanthocyanidins reduce reovirus infectivity titers in African green monkey kidney epithelial cell cultures
Authors: Lipson Steven M. , Cohen Patrice , Zhou Juliana , Burdowski Allan , Stotzky Guenther 
Published: May 2007

AbstractStudies were performed to investigate the effect of several cranberry and grape juice extracts on the inhibition of reovirus infectivity following cell culture inoculation. Infectivity testing was performed utilizing cranberry juice extracts NutriCran‐100TM and NutriCran‐90TM. At 5% extract concentrations, titers were reduced by ca. 50%. Cranberry cocktail juice caused an infectivity loss of ca. 10%. We ascribe these data to higher concentrations of proanthocyanidins (PACs) in the cranberry extracts. Further testing was performed utilizing purified high and low molecular weight cranberry PAC fractions (CB HMW and CB LMW, respectively), a cranberry flavonol glycoside (CB EToAc), cranberry anthocyanins (CB CA), and a grape PAC extract. Reovirus titers were reduced to undetectable levels at PAC concentrations ≤0.2%. CB CA had no effect on the inhibition of infectivity titers. Loss of infectivity titers was in the order: GP PAC>CB HMW>CB LMW>CB EToAc. Probe homogenization of CB HMW enhanced the extract to efficacy levels equal to that of grape PAC. Reovirus dsRNA segments were undetectable 96‐h postcranberry cocktail juice pretreatment of MA‐104 cell cultures. This study indicates an inhibition of reovirus infectivity titers by cranberry or grape juices or their purified PAC extracts. Viral inhibition probably occurs at the host cell surface.
Availability of blueberry phenolics for microbial metabolism in the colon and the potential inflammatory implications
Authors: Russell Wendy R. , Labat Aurélie , Scobbie Lorraine , Duncan Sylvia H. 
Published: May 2007

AbstractBlueberries are a rich source of phenylpropanoid‐derived phytochemicals, widely studied for their potential health benefits. Of particular interest for colonic health are the lower molecular weight phenolic acids and their derivatives, as these are the predominant phenolic compounds detected in the colon. Blueberries contained a wide variety of phenolic acids, the majority of which (3371.14 ± 422.30 mg/kg compared to 205.06 ± 45.34 mg/kg for the free phenolic acids) were attached to other plant cell‐wall components and therefore, likely to become available in the colon. Cytokine‐induced stimulation of the inflammatory pathways in colon cells was four‐fold up‐regulated in the presence of the free phenolic acid fraction. Incubation of the bound phenolic acids with human faecal slurries resulted in qualitative and quantitative differences in the phenolic compounds recovered. The metabolites obtained by incubation with faecal slurries from one volunteer significantly decreased (1.67 ± 0.69 ng/cm3) prostanoid production, whereas an increase (10.78 ± 5.54 ng/cm3) was obtained with faecal slurries from another volunteer. These results suggest that any potential protective effect of blueberry phenolics as anti‐inflammatory agents in the colon is a likely result of microbial metabolism. Studies addressing a wide‐range of well‐characterised human volunteers will be required before such health claims can be fully established.
Optimum sequential search with discrete locations and random acceptance errors
Authors: Smith Mark W. , Walsh John E. 
Published: May 2007

AbstractMuch work has been done in search theory; however, very little effort has occurred where an object's presence at a location can be accepted when no object is present there. The case analyzed is of this type. The number of locations is finite, a single object is stationary at one location, and only one location is observed each step of the search. The object's location has a known prior probability distribution. Also known are the conditional probability of acceptance given the object's absence (small) and the conditional probability of rejection given the object's presence (not too large); these Probabilities remain fixed for all searching and locations. The class of sequential search policies which terminate the search at the first acceptance is assumed. A single two‐part optimization criterion is considered. The search sequence is found which (i) minimizes the probability of obtaining n rejections in the first n steps for all n, and (ii) maximizes the probability that the first acceptance occurs within the first n steps and occurs at the object's location for all n. The optimum sequential search policy specifies that the next location observed is one with the largest posterior probability of the object's presence (evaluated after each step from Bayes Rule) and that the object is at the first location where acceptance occurs. Placement at the first acceptance seems appropriate when the conditional probability of acceptance given the object's absence is sufficiently small. Search always terminates (with probability one). Optimum truncated sequential policies are also considered. Methods are given for evaluating some pertinent properties and for investigating the possibility that no object occurs at any location.
Information in two‐stage programming under uncertainty
Authors: Baron David P. 
Published: May 2007

AbstractThe random variables in two‐stage programming under uncertainty are generally treated in a passive manner in that no information regarding the random variables or the process generating the random variables may be obtained. This paper develops the economics of information for the case in which the probability distributions are discrete. A multinomial process is assumed to generate the random variables, and the parameter vector of that process is assumed to be unknown. A Dirichlet prior distribution on the parameter vector is used, and the computation of the value of information thus involves a Dirichlet‐multinomial distribution on the random variables. An example involving producing to meet uncertain demands is presented.
Extended iterative weighted least squares: Estimation of a linear model in the presence of complications
Authors: Goodman A. F. 
Published: May 2007

AbstractThis paper introduces an extended iterative weighted least squares procedure, denoted by EIWLS, for solution of a classical problem in analysis of scientific and technical information: estimation in the presence of complications, of the coefficients for linearly independent component signals in a linear model, from observations on the component signals and a composite signal containing the linear model plus noise which is nonstationary and/or correlated with unknown covariance matrix. An iterative weighted least squares procedure, denoted by IWLS, is developed for estimation in the absence of complications. Then IWLS is extended to perform the estimation subject to: (1) estimators being consistent with a priori information describing the random variation of coefficients over all possible states of nature (e. g., all systems of a specified type from a production process); (2) utilization of data from all pertinent channels in the estimation of coefficients which appear in the linear models for more than one data channel; and (3) replacment of the linear model by a new linear model containing only representative component signals which are highly‐descriptive, but not highly‐related, when there is a large number of component signals in the linear model and some of them are highly‐related. FORTRAN computer programs have been written to implement IWLS and EIWLS on the IBM 7094 for the case of nonstationary and uncorrelated noise.
Control variable methods in the simulation of a model of a multiprogrammed computer system
Authors: Gaver D. P. , Shedler G. S. 
Published: May 2007

AbstractOne approach to the evaluation of the performance of multiprogranmed computer systems includes the development of Monte Carlo simulations of transitions of programs within such systems, and their strengthening by control variable and concomitant variable methods. An application of such a combination of analytical, numerical, and Monte Carlo approaches to a model of system overhead in a paging machine is presented.
Models for multi‐item continuous review inventory policies subject to constraints
Authors: Schrady D. A. , Choe U. C. 
Published: May 2007

AbstractModels are formulated for determining continuous review (Q, r) policies for a multiitem inventory subject to constraints. The objective function is the minimization of total time‐weighted shortages. The constraints apply to inventory investment and reorder workload. The formulations are thus independent of the normal ordering, holding, and shortage costs. Two models are presented, each representing a convex programming problem. Lagrangian techniques are employed with the first, simplified model in which only the reorder points are optimized. In the second model both the reorder points and the reorder quantities are optimized utilizing penalty function methods. An example problem is solved for each model. The final section deals with the implementation of these models in very large inventory systems.
Optimal location of a single service center of certain types
Authors: Nair K. P. K. , Chandrasekaran R. 
Published: May 2007

AbstractHakimi has considered the problem of finding an optimal location for a single service center, such as a hospital or a police station. He used a graph theoretic model to represent the region being serviced. The communities are represented by the nodes while the road network is represented by the ares of the graph. In his work, the objective is one of minimizing the maximum of the shortest distances between the vertices and the service center. In the present work, the region being serviced is represented by a convex polygon and communities are spread over the entire region. The objective is to minimize the maximum of Euclidian distances between the service center and any point in the polygon. Two methods of solution presented are (i) a geometric method, and (ii) a quadratic programming formulation. Of these, the geometric method is simpler and more efficient. It is seen that for a class of problems, the geometric method is well suited and very efficient while the graph theoretic method, in general, will give only approximate solutions in spite of the increased efforts involved. But, for a different class of problems, the graph theoretic approach will be more appropriate while the geometric method will provide only approximate solutions though with ease. Finally, some feasible applications of importance are outlined and a few meaningful extensions are indicated.
Large deviation probabilities for order statistics
Authors: Book Stephen A. 
Published: May 2007

AbstractAsymptotic representations are found for the large deviation probabilities that the nα‐th order statistic exceeds δ, where δ>α. The probabilities are first expressed in terms of the empirical distribution function, and then the 1960 theorem of Bahadur and Ranga Rao is applied. The result is then shown to be more precise than a logarithmic statement in a 1969 paper of Sievers dealing with the asymptotic relative efficiency of the sample median test.
On the use of standard tables to obtain Dodge‐Romig LTPD sampling inspection plans
Authors: Guenther William C. 
Published: May 2007

AbstractProcedures are described which yield single and double sample Dodge‐Romig [1] lot tolerance percent defective (LTPD) rectifying inspection plans. For the determination of such plans only a desk calculator and standard tables of the discrete probability distributions are required. Some advantages gained by using these procedures rather than the Dodge‐Romig table include: (a) The Consumer's Risk is not limited to 0.10. (b) More choices of LTPD are available. (c) Smaller average total inspection is achieved by using a plan designed for specific “process average” and lot size rather than a compromise plan designed to cover intervals on these two parameters.
A model for manpower productivity during organization growth
Authors: Rau John G. 
Published: May 2007

AbstractA mathematical model is developed that enables organization and manpower planners to quantify the inefficiencies involved in rapid buildups of organizations, such as is frequently found in the aerospace industry shortly after the award of a major contract. Consideration is given to the time required to train, indoctrinate, and familiarize new workers with their jobs and the general program aspects. Once trained, workers are assumed to be productive. If the ratio of untrained to trained workers exceeds a critical value, called the buildup threshold, then the performance of the trained workers is degraded to the extent that they are no longer 100 percent efficient until this ratio returns to a value less than the threshold. The model is sufficiently general to consider an arbitrary manpower plan with more than one peak or valley. The model outputs are functions of real time and consist of the fraction of the total labor force which is productive, the fraction of the total labor units expended for nonproductive effort, the cumulative labor costs for productive effort, and the cumulative labor cost for all effort.
The reliability of multicomponent systems subject to cannibalization
Authors: Simon Richard M. 
Published: May 2007

AbstractA reliability model for multicomponent multistate systems is presented. This is a generalization of a model previously studied by Hirsch, Meisner, and Boll. In the earlier model, when a failure occurs for which no replacement spare is available, the locations using the same type of part as that having failed are “cannibalized” so as to allocate the shortages to locations where they are least detrimental to system performance. Here, we permit certain restrictions to be imposed upon the cannibalization procedure, and develop effective techniques for relating the probability laws governing the level of system performance to the system structure, cannibalization policy, kit of spare parts, and part reliabilities.
An extension of the (szwarc) truck assignment problem
Authors: Bellmore Mandell , Liebman Jon C. , Marks David H. 
Published: May 2007

AbstractIn this journal in 1967. Szware presented an algorithm for the optimal routing of a common vehicle fleet between m sources and n sinks with p different types of commodities. The main premise of the formulation is that a truck may carry only one commodity at a time and must deliver the entire load to one demand area. This eliminates the problem of routing vehicles between sources or between sinks and limits the problem to the routing of loaded trucks between sources and sinks and empty trucks making the return trip. Szwarc considered only the transportation aspect of the problem (i. e., no intermediate points) and presented a very efficient algorithm for solution of the case he described. If the total supply is greater than the total demand, Szwarc shows that the problem is equivalent to a (mp + n) by (np + m) Hitchcock transportation problem. Digital computer codes for this algorithm require rapid access storage for a matrix of size (mp + n) by (np + m); therefore, computer storage required grows proportionally to p2. This paper offers an extension of his work to a more general form: a transshipment network with capacity constraints on all arcs and facilities. The problem is shown to be solvable directly by Fulkerson's out‐of‐kilter algorithm. Digital computer codes for this formulation require rapid access storage proportional to p instead of p2. Computational results indicate that, in addition to handling the extensions, the out‐of‐kilter algorithm is more efficient in the solution of the original problem when there is a mad, rate number of commodities and a computer of limited storage capacity.
Incremental approximation of optimal allocations
Authors: Stone Lawrence D. 
Published: May 2007

AbstractThis paper concerns the approximation of optimal allocations by δ allocations. δ allocations are obtained by fixing an increment δ of effort and deciding at each step upon a single cell in which to allocate the entire increment. It is shown that δ allocations may be used as a simple method of approximating optimal allocations of effort resulting from constrained separable optimization problems involving a finite number of cells. The results are applied to find δ allocations (called δ plans) which approximate optimal search plans. δ plans have the property that as δ → 0, the mean time to find the target using a δ plan approaches the mean time when using the optimal plan. δ plans have the advantage that. they are easily computed and more easily realized in practice than optimal plans which tend to be difficult to calculate and to call for spreading impractically small amounts of effort over large areas.
Generalized implicit enumeration using bounds on variables for solving linear programs with zero‐one variables
Authors: Zionts Stanley 
Published: May 2007

AbstractIn an earlier paper [1] we put forth a framework that helps to tie together a number of approaches for solving integer programming problems. We outlined there how Balas' Additive Algorithm can be explained and generalized in terms of the framework. In the present paper we review Balas' algorithm, and our earlier framework, and present an algorithm generalizing Balas' scheme. In addition, some examples are presented and future research to be done is discussed.