bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reactive oxygen species induce expression of vascular endothelial growth factor in chondrocytes and human articular cartilage explants
Authors: Fay Jakob , Varoga Deike , Wruck Christoph J , Kurz Bodo , Goldring Mary B , Pufe Thomas 
Published: December 2006

AbstractVascular endothelial growth factor (VEGF) promotes cartilage-degrading pathways, and there is evidence for the involvement of reactive oxygen species (ROS) in cartilage degeneration. However, a relationship between ROS and VEGF has not been reported. Here, we investigate whether the expression of VEGF is modulated by ROS.Aspirates of synovial fluid from patients with osteoarthritis (OA) were examined for intra-articular VEGF using ELISA. Immortalized C28/I2 chondrocytes and human knee cartilage explants were exposed to phorbol myristate acetate (PMA; 0–20 μg/ml), which is a ROS inducer, or 3-morpholino-sydnonimine hydrochloride (SIN-1; 0–20 μM), which is a ROS donor. The levels of VEGF protein and nitric oxide (NO) production were determined in the medium supernatant, using ELISA and Griess reagent, respectively. Gene expression of VEGF-121 and VEGF-165 was determined by splice variant RT-PCR. Expression of VEGF and VEGF receptors (VEGFR-1 and VEGFR-2) was quantified by real-time RT-PCR.Synovial fluid from OA patients revealed markedly elevated levels of VEGF. Common RT-PCR revealed that the splice variants were present in both immortalized chondrocytes and cartilage discs. In immortalized chondrocytes, stimulation with PMA or SIN-1 caused increases in the levels of VEGF, VEGFR-1 and VEGFR-2 mRNA expression. Cartilage explants produced similar results, but VEGFR-1 was only detectable after stimulation with SIN-1. Stimulation with PMA or SIN-1 resulted in a dose-dependent upregulation of the VEGF protein (as determined using ELISA) and an increase in the level of NO in the medium.Our findings indicate ROS-mediated induction of VEGF and VEGF receptors in chondrocytes and cartilage explants. These results demonstrate a relationship between ROS and VEGF as multiplex mediators in articular cartilage degeneration.
A Unified Framework for Numerically Inverting Laplace Transforms
Authors: Abate Joseph , Whitt Ward 
Published: December 2006

We introduce and investigate a framework for constructing algorithms to invert Laplace transforms numerically. Given a Laplace transform \hat{f} of a complex-valued function of a nonnegative real-variable, f, the function f is approximated by a finite linear combination of the transform values; i.e., we use the inversion formula f(t) \approx f_n (t) \equiv \frac{1}{t} \sum_{k = 0}^{n}\omega_{k}\hat{f}\biggl(\frac{\alpha_{k}}{t}\biggr),\quad 0 < t < \infty, where the weights ωk and nodes αk are complex numbers, which depend on n, but do not depend on the transform \hat{f} or the time argument t. Many different algorithms can be put into this framework, because it remains to specify the weights and nodes. We examine three one-dimensional inversion routines in this framework: the Gaver-Stehfest algorithm, a version of the Fourier-series method with Euler summation, and a version of the Talbot algorithm, which is based on deforming the contour in the Bromwich inversion integral. We show that these three building blocks can be combined to produce different algorithms for numerically inverting two-dimensional Laplace transforms, again all depending on the single parameter n. We show that it can be advantageous to use different one-dimensional algorithms in the inner and outer loops.
Book Reviews
Authors: Lev Benjamin 
Published: December 2006

The range of books reviewed is wide, covering theory and applications in operations research, statistics, management science, econometrics, mathematics, computers, and information systems (no software is reviewed). In addition, we include books in other fields that emphasize technical applications. Publishers who wish to have their books reviewed should send them to Professor Benjamin Lev. We list the books received; not all books received can be reviewed because space is limited. Those who would like to review books are urged to send me their names, addresses, and specific areas of expertise. We commission all reviews and do not accept unsolicited book reviews. Readers are encouraged to suggest books that might be reviewed or to ask publishers to send me copies of such books. The authors or editors of the books reviewed in this issue are Kenneth R. Baker, Wai-Ki Ching, Michael K. Ng, Manuel Laguna, Rafael Marti, J. Cole Smith, and Jan A. Snyman.
A Dynamic Lot-Sizing Model with Demand Time Windows
Authors: Lee Chung-Yee , Çetinkaya Sila , Wagelmans Albert P. M. 
Published: December 2006

One of the basic assumptions of the classical dynamic lot-sizing model is that the aggregate demand of a given period must be satisfied in that period. Under this assumption, if backlogging is not allowed, then the demand of a given period cannot be delivered earlier or later than the period. If backlogging is allowed, the demand of a given period cannot be delivered earlier than the period, but it can be delivered later at the expense of a backordering cost. Like most mathematical models, the classical dynamic lot-sizing model is a simplified paraphrase of what might actually happen in real life. In most real-life applications, the customer offers a grace period—we call it a demand time window—during which a particular demand can be satisfied with no penalty. That is, in association with each demand, the customer specifies an acceptable earliest and a latest delivery time. The time interval characterized by the earliest and latest delivery dates of a demand represents the corresponding time window. This paper studies the dynamic lot-sizing problem with demand time windows and provides polynomial time algorithms for computing its solution. If backlogging is not allowed, the complexity of the proposed algorithm is O(T2) where T is the length of the planning horizon. When backlogging is allowed, the complexity of the proposed algorithm is O(T3).
Repeated Games with Lack of Information on One Side: The Dual Differential Approach
Authors: Laraki Rida 
Published: December 2006

We introduce the dual differential game of a repeated game with lack of information on one side as the natural continuous time version of the dual game introduced by De Meyer (1996). A traditional way to study the value of differential games is through discrete time approximations. Here, we follow the opposite approach: We identify the limit value of a repeated game in discrete time as the value of a differential game. Namely, we use the recursive structure for the finitely repeated version of the dual game to construct a differential game for which the upper values of the uniform discretization satisfy precisely the same property. The value of the dual differential game exists and is the unique viscosity solution of a first-order derivative equation (which appears implicitely in De Meyer and Rosenberg 1999) with a limit condition. We identify the solution by translating viscosity properties in the primal.
Temporarily Divide to Conquer: Centralized, Decentralized, and Reintegrated Organizational Approaches to Exploration and Adaptation
Authors: Siggelkow Nicolaj , Levinthal Daniel A. 
Published: December 2006

To create a competitive advantage, firms need to find activity configurations that are not only internally consistent, but also appropriate given the firm's current environment. This challenge is particularly acute after firms have experienced an environmental change that has shifted the existing competitive landscape and created new, high-performing sets of activity choices. How should firms organize to explore and search such an altered performance landscape? While it has been noted that adaptive entities need to maintain a balance of exploration and exploitation, little is known about how different organizational structures moderate this balance. With the help of an agentbased simulation model, we study the value of three different organizational structures: a centralized organization, in which decisions are made only at the level of the firm as a whole; a decentralized organization, in which decisions are made independently in two divisions; and a temporarily decentralized firm, which starts out with a decentralized structure and later reintegrates.We find that if interactions among a firm's activities are pervasive, neither the centralized nor the permanently decentralized organizational structure leads to high performance. In this case, temporary decentralization—an organizational structure that has not found much attention in the literature—yields the highest long-term performance. This organizational structure allows the firm both to avoid low-performing activity configurations and to eventually coordinate across its divisions. Thus, even if the decision problem a .rm faces is not fully decomposable, a temporary bifurcation can lead to a higher long-term performance outcome. Initial decentralized exploration is, however, costly in the short run, as compared to centralized exploration. As a result, a tradeoff exists between the short-term costs of decentralized exploration and the longterm benefits of reaching higher performance. As interactions across and within divisions increase, the optimal length of decentralized exploration tends to grow.Paralleling our first result, we further show that even if a decision problem is decomposable, that is, can be perfectly modularized, it can be beneficial to create a temporary decision allocation that creates "unnecessary" interdependencies across the subsystems. This benefit arises in particular when the modules are complex by themselves. In both cases, an initial phase of exploration, enabled by an appropriate organizational structure, followed by refinement and coordination, enabled by a different structure, leads to high performance. To illustrate our general model, we focus on incumbent firms' responses to the Internet and discuss implications for the product design process.
Comparing dichotomous and trichotomous approaches to achievement goal theory: An example using motivational regulations as outcome variables
Authors: Barkoukis Vassilis. , Ntoumanis Nikos. , Nikitaras Nikitas. 
Published: December 2006

Background. It is commonly assumed that there is conceptual equivalence between the task and ego achievement goals proposed by Nicholl's (1989) dichotomous achievement goal theory (Nicholls, 1989), and the mastery and performance approach goals advanced by Elliot's (1997) trichotomous hierarchical model of approach and avoidance achievement motivation.Aims. Our study examined whether this conceptual equivalence is reflected in measurement equivalence by examining the factorial structure and predictive validity of two established questionnaires that assess achievement goals based on Nicholl's and Elliot's approaches to achievement motivation.Sample. Greek adolescents (N=336, M age=13.45 years, SD=1.04).Measures. The participants completed the Task and Ego Orientation in Sport Questionnaire (Duda & Nicholls, 1992), the Approach – Avoidance Achievement Goals Questionnaire (Elliot & Church, 1997) and a Physical Education (PE) version of the Self‐Regulation Questionnaire (Goudas, Biddle, & Fox, 1994).Results. Confirmatory factor analyses of a number of competing models showed that a model with five correlated independent factors had the best fit. This finding suggests that the goals measured by the two achievement goal questionnaires are related, although independent constructs. However, hierarchical regression analyses predicting regulatory styles in PE showed quite a substantial overlap between the mastery and performance approach goals proposed by Elliot (1997), and the task and ego goals, respectively, advanced by Nicholls (1989).Conclusions. Taken together, our results indicate that the self‐referenced and comparative1 goals of the TEOSQ and AAGQ are substantially related, to the extent that they have minimal unique predictive validity; however, they are not identical constructs.
Process flow diagram of an ammonia plant as a complex network
Authors: Jiang Zhi‐Qiang , Zhou Wei‐Xing , Xu Bing , Yuan Wei‐Kang 
Published: January 2007

AbstractComplex networks have attracted increasing interests in almost all disciplines of natural and social sciences. However, few efforts have been afforded in the field of chemical engineering. An example of complex technological network, investigating the process flow of an ammonia plant (AP) is presented. The AP network is a small‐world network with scale‐free distribution of degrees. Adopting Newman's maximum modularity algorithm for the detection of communities in complex networks, evident modular structures are identified in the AP network, which stem from the modular sections in chemical plants. In addition, it is found that the resultant AP tree exhibits excellent allometric scaling. © 2007 American Institute of Chemical Engineers AIChE J 2007
Peopling of South Asia: investigating the caste–tribe continuum in India
Authors: Chaubey Gyaneshwer , Metspalu Mait , Kivisild Toomas , Villems Richard 
Published: December 2006

AbstractIn recent years, mtDNA and Y chromosome studies involving human populations from South Asia and the rest of the world have revealed new insights about the peopling of the world by anatomically modern humans during the late Pleistocene, some 40,000–60,000 years ago, over the southern coastal route from Africa. Molecular studies and archaeological record are both largely consistent with autochthonous differentiation of the genetic structure of the caste and tribal populations in South Asia. High level of endogamy created by numerous social boundaries within and between castes and tribes, along with the influence of several evolutionary forces such as genetic drift, fragmentation and long‐term isolation, has kept the Indian populations diverse and distant from each other as well as from other continental populations. This review attempts to summarize recent genetic studies on Indian caste and tribal populations with the focus on the information embedded in the socially defined structure of Indian populations. BioEssays 29: 91–100, 2007. © 2006 Wiley Periodicals, Inc.
A Fluorous, Pummerer Cyclative‐Capture Strategy for the Synthesis of N‐Heterocycles
Authors: McAllister Laura A. , McCormick Rosemary A. , James Karen M. , Brand Stephen , Willetts Nigel , Procter David J. 
Published: January 2007

AbstractA fluorous, cyclative‐capture strategy based on a new Pummerer cyclization process allows rapid access to tagged, heterocyclic frameworks. Convenient modification of the fluorous, heterocyclic scaffolds by using a variety of approaches including Pd‐catalyzed cross‐couplings is possible. Traceless, reductive cleavage of the fluorous‐phase tag or oxidative cleavage and further elaboration, completes a strategy for the high‐throughput, fluorous‐phase synthesis of a diverse range of N‐heterocycles.
Environmental deterioration and human agency in ancient Macedonia: A case study
Authors: Wiseman James 
Published: December 2006

AbstractStobi, a city inhabited from at least the 4th century B.C. to the late 6th century A.D., is at the confluence of the Vardar and Crna Rivers, now in the former Yugoslav Republic of Macedonia. Archaeological and geologic evidence was used in the 1970s by R. L. Folk to develop a scenario of local environmental degradation, resulting from a postulated widespread climate change (4th–8th centuries A.D.), as a major cause of the decline and eventual abandonment of Stobi. The data for increasingly xeric conditions, catastrophic floods, and mudslides along the Crna River are reviewed and other paleoenvironmental evidence is considered. Subsequent archaeological investigations and a refined chronology reveal repeated episodes of rebuilding along the Crna between periods of flooding. After that portion of the city was abandoned in the mid‐5th century, Stobi achieved new prosperity as reflected in the construction of large‐scale ecclesiastical architecture and houses outside the south city wall. Human agency and periodic extreme weather are proposed as causes of environmental degradation at Stobi. The city's demise is attributed mainly to hostile invasions, plague, earthquake, and the collapse of imperial administrative and economic networks. © 2007 Wiley Periodicals, Inc.
The geographies of ancient ephesus and the Artemision in Anatolia
Authors: Kraft John C. , Bückner Helmut , Kayan Ilhan , Engelmann Helmut 
Published: December 2006

AbstractThis study is a sedimentologic and geomorphologic analysis of ancient geographies of the floodplains and delta of the Küçük Menderes (ancient Cayster River) around the city of Ephesus and the Artemision in Aegean coastal Anatolia. The authors emphasize the interrelationship of archaeological dating and structure, and historical comment in interdisciplinary analysis of ancient geographies and their paleoenvironments. In some cases, the historical literature is specific and factual. In other cases, legend from prehistory may provide important clues to the reconstruction of ancient environments as related to archaeological and historical settings. Ephesus and the closely related Artemision, or Temple of Diana of the Ephesians, offer a chance to link the disciplines of geology, physical geography, archaeology, history, and epigraphy in a composite of paleoenvironmental/paleogeographical interpretations of geomorphology over the past three millennia. Holocene sea‐level rise and marine transgression provide the raised paralic settings of the harbors of Ephesus and the Artemision. The settings of the harbors were altered by continuing progradation of the ancient Cayster River delta‐floodplain over the past three millennia. This research shows how interdisciplinary research greatly enhances our understanding of the ancient geographies of Ephesus and the Artemision.© 2007 Wiley Periodicals, Inc.
A convenient synthesis of 2‐alkoxy‐2‐oxo‐1,4,2‐oxazaphosphinanes
Authors: Wang Bin , Miao Zhiwei , Huang You , Chen Ruyu 
Published: January 2007

AbstractA study on the synthesis of the novel cyclic α‐aminophosphonates and 2‐alkoxy‐2‐oxo‐1,4,2‐oxazaphosphinanes 4a‐r has been carried out. The title compounds were obtained in good yields by one‐pot procedure using o‐aminophenol, alkyl dichlorophosphinite, and ketones or benzaldehyde. One of their geometric stereoisomers was isolated and characterized. Configurations of 4k and one isomer of 4r have been established by X‐ray diffraction analysis. The synthetic methods provide an easy access to the organophosphorus heterocycles with the ring system mentioned above. The abnormal chemical shifts of alkyl‐substitute protons in 1H NMR spectra were given reasonable explanation. © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:65–69, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20258
The immunosuppressant FTY720 inhibits tumor angiogenesis via the sphingosine 1‐phosphate receptor 1
Authors: Schmid Gerald , Guba Markus , Ischenko Ivan , Papyan Armine , Joka Mareile , Schrepfer Sabine , Bruns Christiane J. , Jauch Karl‐Walter , Heeschen Christopher , Graeb Christian 
Published: January 2007

AbstractFTY720, a sphingosine 1‐phosphate (S1P) analog, acts as an immunosuppressant through trapping of T cells in secondary lymphoid tissues. FTY720 was also shown to prevent tumor growth and to inhibit vascular permeability. The MTT proliferation assay illustrated that endothelial cells are more susceptible to the anti‐proliferative effect of FTY720 than Lewis lung carcinoma (LLC1) cells. In a spheroid angiogenesis model, FTY720 potently inhibited the sprouting activity of VEGF‐A‐stimulated endothelial cells even at concentrations that apparently had no anti‐proliferative effect. Mechanistically, the anti‐angiogenic effect of the general S1P receptor agonist FTY720 was mimicked by the specific S1P1 receptor agonist SEW2871. Moreover, the anti‐angiogenic effect of FTY720 was abrogated in the presence of CXCR4‐neutralizing antibodies. This indicates that the effect was at least in part mediated by the S1P1 receptor and involved transactivation of the CXCR4 chemokine receptor. Additionally, we could illustrate in a coculture spheroid model, employing endothelial and smooth muscle cells (SMCs), that the latter confer a strong protective effect regarding the action of FTY720 upon the endothelial cells. In a subcutaneous LLC1 tumor model, the anti‐angiogenic capacity translated into a reduced tumor size in syngeneic C57BL/6 mice. Consistently, in the Matrigel™ plug in vivo assay, 10 mg/kg/d FTY720 resulted in a strong inhibition of angiogenesis as demonstrated by a reduced capillary density. Thus, in organ transplant patients, FTY720 may prove efficacious in preventing graft rejection as well as tumor development. J. Cell. Biochem. 101: 259–270, 2007. © 2007 Wiley‐Liss, Inc.
Sharing experience, conveying hope: Egalitarian relations as the essential method of Alcoholics Anonymous
Authors: Borkman Thomasina 
Published: December 2006

AbstractThe predictions of Max Weber's “iron cage” of bureaucracy and Michels's “iron law of oligarchy” failed to materialize in Alcoholics Anonymous. AA has maintained an alternative form of collectivistic‐democratic voluntary organization for more than seventy years. Its organizational form was developed within its first five years and articulated in its foundational text,Alcoholics Anonymous, published in 1939. Based on detailed histories of its early years, an analysis of AA's crucial ingredients suggests that six factors interacted to avoid the temptations of power, money, and professionalization that would have resulted in a bureaucratic form of organization or oligarchic leadership. In order to avoid death and to obtain or maintain abstinence, the desperate cofounders stumbled on the essential method: egalitarian peers share their lived experiences, conveying hope and strength to one another. In the context of the essential method, the two cofounders, from the Midwest and New York City, held similar spiritual beliefs and practiced a self‐re?exive mode of social experiential learning gained from the Oxford Group, a nondenominational group that advocated healing through personal spiritual change; they downplayed their charismatic authority in favor of consulting with and abiding by the consensus of the group.
Latin America's philanthropic traditions
Authors: Wagner Lilya 
Published: December 2006

AbstractPhilanthropy and Social Change in Latin America, edited by Cynthia Sanborn and Felipe Portocarrero. Cambridge, Mass.: Harvard University Press, 2006. 480 pp., $24.95 paper. New Patterns for Mexico: Observations on Remittances, Philanthropic Giving, and Equitable Development, edited by Barbara J. Merz. Cambridge, Mass.: Harvard University Press, 2006. 312 pp., $19.95 paper.
Hybrid ZnO/III‐nitride light‐emitting diodes: modelling analysis of operation
Authors: Bulashevich K. A. , Evstratov I. Yu. , Karpov S. Yu. 
Published: January 2007

AbstractUsing simulations, we have analysed basic mechanisms of hybrid II–O/III–N light‐emitting diode operation. Factors largely affecting the internal quantum efficiency of hybrid single‐ and double heterostructures, including operation temperature, are examined in detail. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)