bluuebunny/crossref_metadata_2025 huggingface dataset:
Capacity expansion under a service‐level constraint for uncertain demand with lead times
Authors: Marathe Rahul R. , Ryan Sarah M.
Published: January 2009

For a service provider facing stochastic demand growth, expansion lead times and economies of scale complicate the expansion timing and sizing decisions. We formulate a model to minimize the infinite horizon expected discounted expansion cost under a service‐level constraint. The service level is defined as the proportion of demand over an expansion cycle that is satisfied by available capacity. For demand that follows a geometric Brownian motion process, we impose a stationary policy under which expansions are triggered by a fixed ratio of demand to the capacity position, i.e., the capacity that will be available when any current expansion project is completed, and each expansion increases capacity by the same proportion. The risk of capacity shortage during a cycle is estimated analytically using the value of an up‐and‐out partial barrier call option. A cutting plane procedure identifies the optimal values of the two expansion policy parameters simultaneously. Numerical instances illustrate that if demand grows slowly with low volatility and the expansion lead times are short, then it is optimal to delay the start of expansion beyond when demand exceeds the capacity position. Delays in initiating expansions are coupled with larger expansion sizes. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009
Coordination of pricing and inventory control across products
Authors: Zhu Kaijie , Thonemann Ulrich W.
Published: January 2009

We consider the joint pricing and inventory‐control problem for a retailer who orders, stocks, and sells two products. Cross‐price effects exist between the two products, which means that the demand of each product depends on the prices of both products. We derive the optimal pricing and inventory‐control policy and show that this policy differs from the base‐stock list‐price policy, which is optimal for the one‐product problem. We find that the retailer can significantly improve profits by managing the two products jointly as opposed to independently, especially when the cross‐price demand elasticity is high. We also find that the retailer can considerably improve profits by using dynamic pricing as opposed to static pricing, especially when the demand is nonstationary. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009
Scheduling policies for an antiterrorist surveillance system
Authors: Lin Kyle Y. , Kress Moshe , Szechtman Roberto
Published: January 2009

This article concerns scheduling policies in a surveillance system aimed at detecting a terrorist attack in time. Terrorist suspects arriving at a public area are subject to continuous monitoring, while a surveillance team takes their biometric signatures and compares them with records stored in a terrorist database. Because the surveillance team can screen only one terrorist suspect at a time, the team faces a dynamic scheduling problem among the suspects. We build a model consisting of an M/G/1 queue with two types of customers—red and white—to study this problem. Both types of customers are impatient but the reneging time distributions are different. The server only receives a reward by serving a red customer and can use the time a customer has spent in the queue to deduce its likely type. In a few special cases, a simple service rule—such as first‐come‐first‐serve—is optimal. We explain why the problem is in general difficult and we develop a heuristic policy motivated by the fact that terrorist attacks tend to be rare events. © 2009 Wiley Periodicals, Inc. Naval Research Logistics, 2009
MRSI and DTI: a multimodal approach for improved detection of white matter abnormalities in alcohol and nicotine dependence
Authors: Wang Jean J. , Durazzo Timothy C. , Gazdzinski Stefan , Yeh Ping‐Hong , Mon Anderson , Meyerhoff Dieter J.
Published: January 2009

Our previous proton magnetic resonance spectroscopic imaging (1H MRSI) studies showed that the frontal lobe white matter (WM) in smoking recovering alcoholics (sRA) had lower concentrations of N‐acetylaspartate (NAA), a marker for neuron viability, compared to both nonsmoking recovering alcoholics (nsRA) and a control group of nonsmoking light drinkers (nsLD). Using diffusion tensor imaging (DTI) in a similar population, we found lower fractional anistropy (FA), a microstructural measure of WM fiber integrity, in regions of specific fiber bundles within frontal WM of recovering alcoholics compared to light drinkers. In this study, we hypothesized that in these regions of lower FA, NAA concentrations in the alcoholic groups are lower than in non‐alcoholic controls. We hypothesized further that sRA have lower regional NAA concentrations than nsRA. We retrospectively analyzed existing 1H MRSI data by quantitating metabolite concentrations from voxels that corresponded to previously identified WM regions of lower FA, and from a control region of normal FA in alcoholics. We found significant NAA concentration differences between groups in regions of abnormal FA. In particular, sRA had significantly lower NAA concentration than nsLD, but in no region was NAA significantly lower in nsRA than nsLD. Furthermore, no NAA group differences were detected in a frontal WM region of normal FA. These results indicate regionally localized NAA loss within the frontal WM, and specifically NAA loss in regions of low FA. Compared to our previous lobar analyses, DTI‐guided MRSI analysis allows the selective evaluation of small WM regions with microstructural injury, thereby increasing statistical power to detect relevant pathology and group differences. DTI‐guided MRSI analyses promise to contribute to a better understanding of brain injury in alcohol and nicotine dependence and, by extension, perhaps in other neurodegenerative diseases as well. Copyright © 2009 John Wiley & Sons, Ltd.
Gated dynamic 31P MRS shows reduced contractile phosphocreatine breakdown in mice deficient in cytosolic creatine kinase and adenylate kinase
Authors: Kan Hermien E. , Veltien Andor , Arnts Henk , Nabuurs Christine I. H. C. , Luijten Bart , de Haan Arnold , Wieringa Bé , Heerschap Arend
Published: January 2009

We developed a new dedicated measurement protocol for dynamic 31P MRS analysis in contracting calf muscles of the mouse, using minimally invasive assessment of the contractile force combined with the acquisition of spectroscopic data gated to muscle contraction and determination of phosphocreatine (PCr) recovery rate and ATP contractile cost. This protocol was applied in a comparative study of six wild type (WT) mice and six mice deficient in cytosolic creatine kinase and adenylate kinase isoform 1 (MAK−/− mice) using 70 repeated tetanic contractions at two contractions per minute. Force levels during single contractions, and metabolite levels and tissue pH during resting conditions were similar in muscles of MAK−/− and WT mice. Strikingly, muscle relaxation after contraction was significantly delayed in MAK−/− mice, but during repeated contractions, the decrease in the force was similar in both mouse types. Gated data acquisition showed a negligible PCr breakdown in MAK−/− immediately after contraction, without a concomitant decrease in ATP or tissue pH. This protocol enabled the determination of rapid PCr changes that would otherwise go unnoticed due to intrinsic low signal‐to‐noise ratio (SNR) in mouse skeletal muscles combined with an assessment of the PCr recovery rate. Our results suggest that MAK−/− mice use alternative energy sources to maintain force during repeated contractions when PCr breakdown is reduced. Furthermore, the absence of large increases in adenosine diphosphate (ADP) or differences in force compared to WT mice in our low‐intensity protocol indicate that creatine kinase (CK) and adenylate kinase (AK) are especially important in facilitating energy metabolism during very high energy demands. Copyright © 2009 John Wiley & Sons, Ltd.
A note on spectrum distribution of constraint preconditioned generalized saddle point matrices
Authors: Cao Zhi‐Hao
Published: January 2009

In this note, results concerning the eigenvalue distribution and form of the eigenvectors of the constraint preconditioned generalized saddle point matrix and its minimal polynomial are given. These results extend previous ones that appeared in the literature. Copyright © 2009 John Wiley & Sons, Ltd.
Reduced‐order modeling of parameterized PDEs using time–space‐parameter principal component analysis
Authors: Audouze C. , De Vuyst F. , Nair P. B.
Published: January 2009

This paper presents a methodology for constructing low‐order surrogate models of finite element/finite volume discrete solutions of parameterized steady‐state partial differential equations. The construction of proper orthogonal decomposition modes in both physical space and parameter space allows us to represent high‐dimensional discrete solutions using only a few coefficients. An incremental greedy approach is developed for efficiently tackling problems with high‐dimensional parameter spaces. For numerical experiments and validation, several non‐linear steady‐state convection–diffusion–reaction problems are considered: first in one spatial dimension with two parameters, and then in two spatial dimensions with two and five parameters. In the two‐dimensional spatial case with two parameters, it is shown that a 7 × 7 coefficient matrix is sufficient to accurately reproduce the expected solution, while in the five parameters problem, a 13 × 6 coefficient matrix is shown to reproduce the solution with sufficient accuracy. The proposed methodology is expected to find applications to parameter variation studies, uncertainty analysis, inverse problems and optimal design. Copyright © 2009 John Wiley & Sons, Ltd.
An error estimate of the proper orthogonal decomposition in model reduction and data compression
Authors: Wang A‐xia , Ma Yi‐Chen
Published: January 2009

A kind of the proper orthogonal decomposition (POD) is used for data compression of rugged surface and reduction of the Navier–Stokes equations. An error estimate of the POD in model reduction and data compression is discussed. The numerical examples show that the error between the POD approximate solution and reference solution is consistent with theoretical results, and also show that the proposed algorithm is feasible and efficient. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2009
A numerical approximation to the solution of an inverse heat conduction problem
Authors: Azari Hossein , Zhang Shuhua
Published: January 2009

The aim of this article is to study the parabolic inverse problem of determination of the leading coefficient in the heat equation with an extra condition at the terminal. After introducing a new variable, we reformulate the problem as a nonclassical parabolic equation along with the initial and boundary conditions. The uniqueness and continuous dependence of the solution upon the data are demonstrated, and then finite difference methods, backward Euler and Crank–Nicolson schemes are studied. The results of some numerical examples are presented to demonstrate the efficiency and the rapid convergence of the methods. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
Land conflicts, rural finance and capacity of the Chinese state
Authors: Yep Ray , Fong Carolin
Published: January 2009

This article evaluates the capacity of the Chinese state in maintaining stability by examining the merits and limitations of its responses to the dominant form of rural unrest in recent years: conflicts over land. The current response of the Chinese state that focusses on upward accountability of state agents is misguided. We argue that the ultimate solution hinges upon the success of the Chinese state in strengthening its capacity in engaging society and capability to reformulate a new fiscal order that provides adequate resources for effective governance at rural grass roots. Copyright © 2009 John Wiley & Sons, Ltd.
‘If You Can't Budget, How Can You Govern?’—A study of China's state capacity
Authors: Ma Jun
Published: January 2009

State capacity matters. Using China as a case study, this essay contends that the capacity to budget is a general underpinning of state capacity regardless of how it is defined. For a state like China to enhance its capacity to budget, it must first concentrate on the issue of institutionalizing the basic controlling systems. Until this has been achieved, a move towards a more advanced budgetary system is unlikely to be successful. Copyright © 2009 John Wiley & Sons, Ltd.
Development and validation of a novel protein extraction methodology for quantitation of protein expression in formalin‐fixed paraffin‐embedded tissues using western blotting
Authors: Nirmalan Niroshini J , Harnden Patricia , Selby Peter J , Banks Rosamonde E
Published: January 2009

The development of efficient formaldehyde cross‐link reversal strategies will make the vast diagnostic tissue archives of pathology departments amenable to prospective and retrospective translational research, particularly in biomarker‐driven proteomic investigations. Heat‐induced antigen retrieval strategies (HIARs) have achieved varying degrees of cross‐link reversal, potentially enabling archival tissue usage for proteomic applications outside its current remit of immunohistochemistry (IHC). While most successes achieved so far have been based on retrieving tryptic peptide fragments using shot‐gun proteomic approaches, attempts at extracting full‐length, non‐degraded, immunoreactive proteins from archival tissue have proved challenging. We have developed a novel heat‐induced antigen retrieval strategy using SDS‐containing Laemmli buffer for efficient intact protein recovery from formalin‐fixed tissues for subsequent analysis by western blotting. Protocol optimization and comparison of extraction efficacies with frozen tissues and current leader methodology is presented. Quantitative validation of methodology was carried out in a cohort of matched tumour/normal, frozen/FFPE renal tissue samples from 10 patients, probed by western blotting for a selected panel of seven proteins known to be differentially expressed in renal cancer. Our data show that the protocol enables efficient extraction of non‐degraded, full‐length, immunoreactive protein, with tumour versus normal differential expression profiles for a majority of the panel of proteins tested being comparable to matched frozen tissue controls (rank correlation, r = 0.7292, p < 1.825e‐09). However, the variability observed in extraction efficacies for some membrane proteins emphasizes the need for cautious interpretation of quantitative data from this subset of proteins. The method provides a viable, cost‐effective quantitative option for the validation of potential biomarker panels through a range of clinical samples from existing diagnostic archives, provided that validation of the method is first carried out for the specific proteins under study. Copyright © 2008 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Gene expression profiling provides insights into the pathways involved in solid pseudopapillary neoplasm of the pancreas
Authors: Cavard Catherine , Audebourg Anne , Letourneur Franck , Audard Virginie , Beuvon Frédéric , Cagnard Nicolas , Radenen Brigitte , Varlet Pascale , Vacher‐Lavenu Marie‐Cécile , Perret Christine , Terris Benoit
Published: January 2009

Solid‐pseudopapillary neoplasms (SPNs) are rare human pancreatic neoplasms usually associated with a good prognosis. In contrast to other pancreatic tumours, aberrant activation of the Wnt–β‐catenin pathway appears to be a constant feature in SPN. Aside from activation of the Wnt–β‐catenin pathway, little is known about biological pathways deregulated in SPN. We carried out transcriptome profiling of SPN to gain insights into the pathogenesis of these tumours. As expected, the over‐expression of AXIN2, TBX3, SP5 and NOTUM demonstrated activation of the β‐catenin pathway. Members of the Notch pathway (HEY1, HEY2, NOTCH2) were also up‐regulated, relative to their expression in ductal adenocarcinomas (DAC) or pancreatic endocrine tumours (PET). Other genes, such as EDN3, HAND2, netrin‐G2 and the receptor netrin‐G1 ligand, involved in neural crest differentiation, were also identified as altered. Increased levels of SOX10 and TuJ‐1 proteins were also indicative of neural‐like differentiation. In conclusion, SPN display a complex expression profile, distinct from that observed in PET and DAC and involving both the β‐catenin and Notch pathways, together with expression of neural differentiation markers. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Disruption of tight junctions during polymicrobial sepsis in vivo
Authors: Li Qiurong , Zhang Qiang , Wang Chenyang , Liu Xiaoxiang , Li Ning , Li Jieshou
Published: January 2009

The disruption of intestinal epithelial tight junctions may result in barrier function dysfunction during polymicrobial sepsis. The pathophysiology of sepsis involves breakdown of barrier integrity, which correlates with adverse outcome during sepsis. However, the mechanisms underlying loss of barrier function in sepsis remain unknown. In the present study in mice, tight junction (TJ) structure was analysed by transmission electron microscopy; intestinal permeability was assessed using molecular tracer measurement; and the distribution of TJ proteins was investigated by immunofluorescence microscopy. The membrane microdomains of TJs were isolated using discontinuous sucrose density gradients and the expression of TJ proteins in these was determined by western blot. Immunofluorescence microscopy revealed that claudins 1, 3, 4, 5, and 8 were present predominantly in the microvillous surface of epithelial cells and along the lateral membranes of the cells; in sepsis, however, labelling of these proteins was present diffusely within cells and was no longer focused at the lateral cell boundaries. Moreover, the expression of claudin‐2 was markedly up‐regulated in sepsis. Using western blot analysis, we found that occludin and claudins were displaced from raft fractions to non‐raft fractions in membrane microdomains of TJs in sepsis. In addition, the disruption of TJ structure was accompanied by increased intestinal permeability. Our results demonstrate for the first time that redistribution of TJ proteins in TJ membrane microdomains and redistribution of claudins in epithelial cells of the colon lead to alteration of TJ architecture and TJ barrier dysfunction during the development of polymicrobial sepsis. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Contribution of fetal cerebral MRI for diagnosis of structural anomalies
Authors: Guibaud Laurent
Published: January 2009

More than 20 years after its introduction, magnetic resonance imaging (MRI) is now considered a useful complementary tool in the imaging work‐up of fetal brain structural anomalies, but its real contribution in neuro‐fetal imaging is still controversial. Our purpose is to present an overview of the most valuable indications of fetal cerebral MRI in current practice as guided by dedicated ultrasound analysis. On the basis of a review of the literature and our personal experience, we underline herein the real complementarities between these two techniques in different clinical or imaging settings and show how MRI adds significant information compared with ultrasound, especially in the late second and third trimesters. We assess the interest of using MRI from a technical point of view (complete and extensive anatomical analysis, analysis of developmental and pathological processes) and from a practical point of view in different imaging and clinical settings. Copyright © 2009 John Wiley & Sons, Ltd.
Onset and relapse of psychiatric disorders following early breast cancer: a case–control study
Authors: Gandubert Catherine , Carrière Isabelle , Escot Chantal , Soulier Maryvonne , Hermès Aziz , Boulet Patrick , Ritchie Karen , Chaudieu Isabelle
Published: January 2009

Objective: Our objective is to evaluate the mental status of primary early breast cancer survivors according to DSM‐IV criteria, distinguishing new psychiatric diagnosis, which started after the cancer diagnosis from relapse.

Methods: A comparative study of 144 breast cancer survivors and 125 women without previous history of cancer was carried out. Neuropsychiatric symptomatology was assessed retrospectively using standardized psychiatric examinations (Mini International Neuropsychiatric Interview, Watson's Post‐Traumatic Stress Disorder Inventory) over three successive periods, ‘before cancer’ (from childhood to 3 years before the interview), ‘around the cancer event’ (the last 3 years including the time of diagnosis and treatment), and ‘currently’ (the last 2 weeks).

Results: Increased rates of anxiety and mood disorders were observed following a diagnosis of breast cancer compared with controls (generalized anxiety disorder (GAD) and major depressive disorder (MDD); 10.4 vs 1.6% and 19.4 vs 8.8%, respectively). The cancer disease promoted the development of dysthymia (n=4 new cases/6 two‐year prevalent cases) and PTSD (7/7) and the re‐emergence of MDD (n=21 relapses/28 three‐year prevalent cases) and GAD (10/15). No improvement in serious mood disorders such as MDD (16.0 vs 7.2%) and dysthymia (4.2 vs 0%) was reported at the time of interview, more than 1.75 years (median time) after the cancer surgery, the prevalence being 2–4 times greater in breast cancer survivors than in controls.

Conclusion: Despite significant advances in treatment, a diagnosis of breast cancer is highly associated with various forms of psychopathology, regardless of psychiatric history, with symptoms persisting after treatment. These results may assist clinicians in planning mental healthcare for women with breast cancer. Copyright © 2009 John Wiley & Sons, Ltd.
Strain effects in GaN/AlN short‐period superlattices for intersubband optoelectronics
Authors: Kandaswamy Prem Kumar , Jalabert Denis , Bougerol Catherine , Bellet‐Amalric Edith , Lahourcade Lise , Monroy Eva
Published: January 2009

In this work we report on the strain relaxation processes in GaN/AlN short‐period superlattices (SLs) displaying intersubband transitions at 1.55 μm. The growth process was tuned to minimize the strain relaxation in the superlattices either by plastic or elastic channels. X‐ray diffraction measurements show that the SL final strain state is substrate independent. The relaxation path followed by the SLs was traced in situ with reflection high‐energy electron diffraction, which reveals an initial transient strain state of about 12 periods to accommodate the lattice mismatch. Once steady‐state conditions are attained, we observe a periodic relaxation process with generation of misfit dislocations at the GaN/AlN interface. The relaxation process in the SLs has been confirmed by various characterization tools. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Off‐angle dependence of void formation and defect behavior in a ‐plane MOVPE‐GaN on r ‐plane sapphire substrate
Authors: Kuwano Noriyuki , Fukushima Atsuhito , Kugiyama Yuta , Ezaki Tetsuya , Minami Masahiro , Araki Masahiko , Hoshino Katsuyuki , Tadatomo Kazuyuki
Published: January 2009

Transmission electron microscope (TEM) observation was performed to analyze microstructures in a (11$ \bar 2 $0)‐plane GaN thin films grown by metal‐organic vapor‐phase epitaxy (MOVPE) on a r (1$ \bar 1 $02)‐plane sapphire substrate Special attention was paid to an influence of small off‐angle of the substrate plane to morphology of defects in the thin films. From the TEM observation, the following results were drawn. (1) The crystallographic orientation relationship between GaN and sapphire substrate is (11$ \bar 2 $0)[0001][$ \bar 1 $100]GaN // (1$ \bar 1 $02)[$ \bar 1 $101][11$ \bar 2 $0]sapphire. The direction of +c ‐polarity coincides with that reported previously. (2) The pits on the surface are formed on the grain boundaries of GaN. (3) The density of pits is related with the density of nucleation of GaN‐islands on the substrate. The increase in density of pits with the off‐angle can be explained by the increase of nucleation sites provided by atomic steps on the substrate. (4) The side‐wall planes of pits and voids are considered to be closed to ±(0001), ±(11$ \bar 2 $4), and (11$ \bar 2 $2). (5) The formation of pits and voids are attributable to the trend that such inclining planes as (11$ \bar 2 $2) and (11$ \bar 2 $4) are stable compared with +c (0001). A possible technique for reduction of defects is also discussed. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Possibility of AlN vapor phase epitaxy using Li3N as a nitrogen source
Authors: Kangawa Y. , Nagano T. , Kakimoto K.
Published: January 2009

Possibility of AlN vapor phase epitaxy using Al and Li3N as source materials was investigated. Grown product on sapphire substrate was identified by XRD and Micro‐Raman measurements. The results suggest that AlON was formed under Li‐N‐rich condition though AlN was formed under Al‐rich condition. This is because Li3N corroded surface of sapphire and oxygen, which is a constituent element of substrate, was incorporated in the product. Moreover, it is found that AlN nano‐wire was formed when excessive Al was supplied during growth. These results imply that it is possible to grow AlN by choosing proper conditions especially Li‐N/Al ratio. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Improved capping layer growth towards increased stability of InGaN quantum dots
Authors: Tessarek Christian , Yamaguchi Tomohiro , Figge Stephan , Hommel Detlef
Published: January 2009

Improvements in GaN capping layer growth towards increased stability of InGaN quantum dots (QDs) will be presented. Surface quality is enhanced with changing the carrier gas during GaN capping layer growth from nitrogen to hydrogen. Without a dissolution of QDs it is possible to increase the temperature to 1050 °C applying a temperature ramp during growth of GaN.

Dot stacks with an uniform and up to room temperature bright photoluminescence emission spectra is reported qualifying the structure to be incorporated into LED and laser structures. Finally, the evolution of the nucleation layer into flat and broad island‐like structures will be explained by the spinodal decomposition model (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth mode of InGaN on GaN (0001) in MOVPE
Authors: Pristovsek M. , Stellmach J. , Leyer M. , Kneissl M.
Published: January 2009

We investigated the growth of InGaN films of 10 nm and thicker on GaN at different temperatures with insitu ellipsometry, ex‐situ X‐ray diffraction and atomic force microscopy. Depending on growth temperature all layers showed at least one distinct growth mode transition either to a coherently strained lateral decomposed rough layer or to a relaxed layer. Indium incorporation on the relaxed layer was much higher, with an activation energy of ≈ 0.6 eV compared to the strained layer (EA ≈ 2.1 eV).

The growth apparently proceeds first as a smooth homogeneous layer in the Stranski‐Krastanov growth mode. After the onset of 3D growth the layer is still fully strained but lateral decomposition sets on, because the heighest areas can expand horizontally more easily and thus incorporate more indium. Finally the critical thickness is reached and the layer starts to relax. The critical thickness for Stranski‐Krastanov is proportional to xIn –1 and the critical thickness for relaxation is proportional xIn –2 (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Near band‐gap photoluminescence of InN due to Mahan excitons
Authors: Feneberg Martin , Däubler Jürgen , Thonke Klaus , Sauer Rolf , Schley Pascal , Goldhahn Rüdiger
Published: January 2009

The luminescence spectrum of degenerately n‐type doped hexagonal InN extends to energies significantly higher than the renormalized band edge of the material. The line shape cannot be explained by simple band‐filling. Reflectivity spectra reveal at low temperatures a strongly enhanced intensity at the Fermi energy which we ascribe to a Fermi edge singularity of the electrons interacting with holes to form so‐called Mahan excitons. High k ‐values of the holes recombining with Fermi edge electrons are provided by localization at acceptors. A weak binding energy for a Mahan exciton is expected due to screening of the electron liquid in the conduction band. The concept of Mahan excitons allows us to understand the observed near band gap photoluminescence spectra (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Molecular mechanisms of cervical carcinogenesis by high‐risk human papillomaviruses: novel functions of E6 and E7 oncoproteins
Authors: Yugawa Takashi , Kiyono Tohru
Published: January 2009

Over the last two decades, since the initial discovery of human papillomavirus (HPV) type 16 and 18 DNAs in cervical cancers by Dr. Harald zur Hausen (winner of the Nobel Prize in Physiology or Medicine, 2008), the HPVs have been well characterised as causative agents for cervical cancer. Viral DNA from a specific group of HPVs can be detected in at least 90% of all cervical cancers and two viral genes, E6 and E7, are invariably expressed in HPV‐positive cervical cancer cells. Their gene products are known to inactivate the major tumour suppressors, p53 and retinoblastoma protein (pRB), respectively. In addition, one function of E6 is to activate telomerase, and E6 and E7 cooperate to effectively immortalise human primary epithelial cells. Though expression of E6 and E7 is itself not sufficient for cancer development, it seems to be either directly or indirectly involved in every stage of multi‐step carcinogenesis. Epidemiological and biological studies suggest the potential efficacy of prophylactic vaccines to prevent genital HPV infection as an anti‐cancer strategy. However, given the widespread nature of HPV infection and unresolved issues about the duration and type specificity of the currently available HPV vaccines, it is crucial that molecular details of the natural history of HPV infection as well as the biological activities of the viral oncoproteins be elucidated in order to provide the basis for development of new therapeutic strategies against HPV‐associated malignancies. This review highlights novel functions of E6 and E7 as well as the molecular mechanisms of HPV‐induced carcinogenesis. Copyright © 2009 John Wiley & Sons, Ltd.
Interfacial studies on the ozone and air‐oxidation‐modified carbon fiber reinforced PEEK composites
Authors: Li J.
Published: January 2009

In this work, ozone modification method and air‐oxidationwere used for the surface treatment of polyacrylonitrile(PAN)‐based carbon fiber. The surface characteristics of carbon fibers were characterized by XPS. The interfacial properties of carbon fiber‐reinforced (polyetheretherketone) PEEK (CF/PEEK) composites were investigated by means of the single fiber pull‐out tests. As a result, it was found that IFSS (interfacial shear strength) values of the composites with ozone‐treated carbon fiber are increased by 60% compared to that without treatment. XPS results show that ozone treatment increases the amount of carboxyl groups on carbon fiber surface, thus the interfacial adhesion between carbon fiber and PEEK matrix is effectively promoted. The effect of surface treatment of carbon fibers on the tribological properties of CF/PEEKcomposites was comparativelyinvestigated. Experimental results revealed that surface treatment can effectively improve the interfacial adhesion between carbon fiber and PEEK matrix. Thus the wear resistance was significantly improved. Copyright © 2009 John Wiley & Sons, Ltd.
Photoelectron spectroscopy on organic surfaces: X‐ray degradation of oxygen‐plasma‐treated and chemically reduced poly(propylene) surfaces in comparison to conventional polymers
Authors: Gross Thomas , Kühn Gerhard , Unger Wolfgang E. S.
Published: January 2009

The X‐ray‐induced sample damage during mono XPS analysis of an oxygen‐plasma‐oxidized and subsequently wet‐chemically reduced poly(propylene) film was investigated as a showcase for plasma‐modified or plasma‐deposited samples. By doing this, the degradation index approach as introduced by Beamson and Briggs in the Scienta ESCA300 high‐resolution XPS database of organic polymers has been adopted. As to be expected, the sample degrades by loosing oxygen as revealed by observation of decreasing O/C and COR/Csum ratios. However, the X‐ray degradation indices are definitely higher than those of conventional reference polymers. Moreover, the COR/Csum degradation index is significantly higher in comparison with one obtained for the O/C ratio. In that context, there is no difference between the plasma sample and a conventional poly(vinyl alcohol) polymer. It is concluded that for reliable quantitative surface chemical analysis, the quality of spectra in terms of acquisition times must be optimized aimed to a minimization of X‐ray degradation. Finally, it is proposed to describe the photon flux of an X‐ray gun in an XPS experiment, which defines the degradation rate at the end, by using the sample current simply measured with a carefully grounded sputter‐cleaned reference silver sample. Copyright © 2009 John Wiley & Sons, Ltd.
How to evaluate the calibration of a disease risk prediction tool
Authors: Viallon Vivian , Ragusa Stéphane , Clavel‐Chapelon Françoise , Bénichou Jacques
Published: January 2009

To evaluate the calibration of a disease risk prediction tool, the quantity E/O, i.e. the ratio of the expected to the observed number of events, is usually computed. However, because of censoring, or more precisely because of individuals who drop out before the termination of the study, this quantity is generally unavailable for the complete population study and an alternative estimate has to be computed. In this paper, we present and compare four methods to do this. We show that two of the most commonly used methods generally lead to biased estimates. Our arguments are first based on some theoretic considerations. Then, we perform a simulation study to highlight the magnitude of biases. As a concluding example, we evaluate the calibration of an existing predictive model for breast cancer on the E3N–EPIC cohort. Copyright © 2009 John Wiley & Sons, Ltd.
A comparison of tests for restricted orderings in the three‐class case
Authors: Alonzo Todd A. , Nakas Christos T. , Yiannoutsos Constantin T. , Bucher Sherri
Published: January 2009

A variety of methods for comparing three distributions have been proposed in the literature. These methods assess the same null hypothesis of equal distributions but differ in the alternative hypothesis they consider. The alternative hypothesis can be that measurements from the three classes are distributed according to unequal distributions or that measurements between the three classes follow a specific monotone ordering, an inverse‐U‐shaped (umbrella) ordering, or a U‐shaped (tree) ordering. This paper compares these tests with respect to power and test size under different simulation scenarios. In addition, the methods are illustrated in two applications generated by different research questions with data from three classes suggesting monotone and umbrella orders. Additionally, proposals for the appropriate application of these tests are provided. Copyright © 2009 John Wiley & Sons, Ltd.
FLORA: a framework for decomposing software architecture to introduce local recovery
Authors: Sözer Hasan , Tekinerdoğan Bedir , Akşit Mehmet
Published: January 2009

The decomposition of software architecture into modular units is usually driven by the required quality concerns. In this paper we focus on the impact of local recovery concern on the decomposition of the software system. For achieving local recovery, the system needs to be decomposed into separate units that can be recovered in isolation. However, it appears that this required decomposition for recovery is usually not aligned with the decomposition based on functional concerns. Moreover, introducing local recovery to a software system, while preserving the existing decomposition, is not trivial and requires substantial development and maintenance effort. To reduce this effort we propose a framework that supports the decomposition and implementation of software architecture for local recovery. The framework provides reusable abstractions for defining recoverable units and the necessary coordination and communication protocols for recovery. We discuss our experiences in the application and evaluation of the framework for introducing local recovery to the open‐source media player called MPlayer. Copyright © 2009 John Wiley & Sons, Ltd.
Extreme winds from the NCEP/NCAR reanalysis data
Authors: Larsén Xiaoli Guo , Mann Jakob
Published: January 2009

In this study, we test a method to estimate the extreme winds by using the NCEP/NCAR reanalysis data. From the reanalysis pressure or geopotential height records, the geostrophic wind is first calculated, and then extrapolated to 10 m height over a homogeneous surface with roughness length of 0.05 m, i.e. the so‐called standard wind. The software Wind Analysis and Application Program will then use this standard wind in a flow model, with the roughness, orography and obstacles around the turbine site to obtain the site‐specific wind. The ‘annual maximum method’ is used to calculate the 50 year wind. We examined extreme winds in different places where the strongest wind events are weather phenomena of different scales, including the mid‐latitude lows in Denmark, channelling winds in the Gulf of Suez, typhoons in the western North Pacific, cyclones in the Caribbean Sea, local strong winds: the Mistral in the Gulf of Lions and the Bora in the north Adriatic Sea. It was found that the method introduced here can be applied to places where the extreme wind events are synoptic weather phenomena like in north‐western Europe, but a more complicated downscaling, e.g. based on a mesoscale model, is needed for places where the extreme wind events are of mesoscale origin. Copyright © 2009 John Wiley & Sons, Ltd.
Tetrahedral [Tt4]4– Zintl Anions Through Solution Chemistry: Syntheses and Crystal Structures of the Ammoniates Rb4Sn4·2NH3, Cs4Sn4·2NH3, and Rb4Pb4·2NH3
Authors: Wiesler Katharina , Brandl Karoline , Fleischmann Andrea , Korber Nikolaus
Published: January 2009

The crystalline isotypic solvates Rb4Sn4·2NH3, Cs4Sn4·2NH3, and Rb4Pb4·2NH3 have been synthesized using the direct reduction of elemental tin or tetraphenyltin, respectively, with heavier alkali metals or the dissolution of the binary phase RbPb in liquid ammonia. These compounds contain the cluster ions [Sn4]4– or [Pb4]4– respectively. This is the first time that[Tt4]4– ions (Tt = tetrels) are detected as result of a solution reaction. The accommodation of the ammonia molecules, which build up ion‐dipole interactions to alkali metal cations, requires some modifications of the crystal structures compared to the binary phases RbSn, CsSn, and RbPb. The tetrahedral [Tt4]4– anions have a slightly lower coordination by Rb+ or Cs+ cations and, furthermore, the intercluster distances show a remarkable increase.
Neuropathy After Herniorrhaphy: Indication for Surgical Treatment and Outcome
Authors: Vuilleumier Henri , Hübner Martin , Demartines Nicolas
Published: January 2009

Background

Chronic neuropathy after hernia repair is a neglected problem as very few patients are referred for surgical treatment. The aim of the present study was to assess the outcome of standardized surgical revision for neuropathic pain after hernia repair.

Methods

In a prospective cohort study we evaluated all patients admitted to our tertiary referral center for surgical treatment of persistent neuropathic pain after primary herniorrhaphy between 2001 and 2006. Diagnosis of neuropathic pain was based on clinical findings and a positive Tinel’s sign. Postoperative pain was evaluated by a visual analogue scale (VAS) and a pain questionnaire up to 12 months after revision surgery.

Results

Forty‐three consecutive patients (39 male, median age 35 years) underwent surgical revision, mesh removal, and radical neurectomy. The median operative time was 58 min (range: 45–95 min). Histological examination revealed nerve entrapment, complete transection, or traumatic neuroma in all patients. The ilioinguinal nerve was affected in 35 patients (81%); the iliohypogastric nerve, in 10 patients (23%). Overall pain (median VAS) decreased permanently after surgery within a follow‐up period of 12 months (preoperative 74 [range: 53–87] months versus 0 [range: 0–34] months; p < 0.0001).

Conclusions

The results of this cohort study suggest that surgical mesh removal with ilioinguinal and iliohypogastric neurectomy is a successful treatment in patients with neuropathic pain after hernia repair.
Estimation of the Nonlinear Random Coefficient Model when Some Random Effects Are Separable
Authors: du Toit Stephen H. C. , Cudeck Robert
Published: January 2009

A method is presented for marginal maximum likelihood estimation of the nonlinear random coefficient model when the response function has some linear parameters. This is done by writing the marginal distribution of the repeated measures as a conditional distribution of the response given the nonlinear random effects. The resulting distribution then requires an integral equation that is of dimension equal to the number of nonlinear terms. For nonlinear functions that have linear coefficients, the improvement in computational speed and accuracy using the new algorithm can be dramatic. An illustration of the method with repeated measures data from a learning experiment is presented.
Dislocation of the Carpometacarpal Joint of the Thumb Associated with Trapezium and Bennett's Fractures
Authors: Ibrahimi A. El , Amar F. , Chbani B. , Daoudi A. , Elmrini A. , Boutayeb F.
Published: January 2009

We report a case of a 30-year-old man with a carpometacarpal joint dislocation of the thumb associated with trapezium and Bennett's fractures. This combined injury pattern appears to be very rare. Since, to our knowledge a similar case was not found in the literature. The lesion was managed with closed reduction and percutaneous pining, resulting in good functional outcome.
Thermally Induced Nano-Structural and Optical Changes of nc-Si:H Deposited by Hot-Wire CVD
Authors: Arendse CJ , Malgas GF , Muller TFG , Knoesen D , Oliphant CJ , Motaung DE , Halindintwali S , Mwakikunga BW
Published: January 2009

We report on the thermally induced changes of the nano-structural and optical properties of hydrogenated nanocrystalline silicon in the temperature range 200–700 °C. The as-deposited sample has a high crystalline volume fraction of 53% with an average crystallite size of ~3.9 nm, where 66% of the total hydrogen is bonded as ≡Si–H monohydrides on the nano-crystallite surface. A growth in the native crystallite size and crystalline volume fraction occurs at annealing temperatures ≥400 °C, where hydrogen is initially removed from the crystallite grain boundaries followed by its removal from the amorphous network. The nucleation of smaller nano-crystallites at higher temperatures accounts for the enhanced porous structure and the increase in the optical band gap and average gap.
Credit Access, the Costs of Credit and Credit Market Discrimination
Authors: Weller Christian E.
Published: January 2009

Since the early 1990s, credit expanded relative to income, especially after 2001. It is hypothesized that traditionally uneven credit access and gaps in the costs of credit by demographic characteristics shrank during this period. Relying on data from the Federal Reserve's Survey of Consumer Finance, this study looks at financial constraints, the costs of credit and a number of contributions to the costs of credit, including sources and types of loans. The results indicate that taste-based discrimination and structural discrimination may have persisted and possibly increased over time. Gaps in credit access and costs of credit have widened by race, remained high by income, but shrank by ethnicity. Part of the overall differences in credit access was a varying reliance on professional information when making decisions on debt.
Effect of chitooligosaccharide on neuronal differentiation of PC‐12 cells
Authors: Yang Yumin , Liu Mei , Gu Yun , Lin Sheyu , Ding Fei , Gu Xiaosong
Published: January 2009

Chitosan is now being widely used biomaterial in the tissue engineering field, and has great potential as a candidate material for preparing nerve guidance conduits due to its various favorable properties, especially that of good nerve cell affinity. Chitosan can be degraded in vivo into chitooligosaccharide. We have investigated the in vitro effects of chitooligosaccharide on neuronal differentiation of PC‐12 cells to see what effects chitooligosaccharide have on certain functions in the regenerating neurons. The morphologic observation and assessment using the specific reagent of tetrazolium salt WST‐8 indicated that neurite outgrowths from PC‐12 cells and the viability of PC‐12 cells were enhanced by treatment of chitooligosaccharide. The real‐time quantitative RT‐PCR and Western blot analysis revealed showed that chitooligosaccharide could upregulate the expression of neurofilament‐H mRNA or protein and N‐cadherin protein in PC‐12 cells. The maximum effect of 0.1 mg/ml chitooligosaccharide was obtained after 2 week culture. All the data suggest that chitooligosaccharide possesses good nerve cell affinity by supporting nerve cell adhesion and promoting neuronal differentiation and neurite outgrowth.
Human bone marrow mesenchymal stem cells are resistant to HBV infection during differentiation into hepatocytes in vivo and in vitro
Authors: Xie Chan , Zheng Yu‐Bao , Zhu Hai‐Peng , Peng Liang , Gao Zhi‐Liang
Published: January 2009

Hepatocyte‐like cells induced from bone marrow mesenchymal stem cells (BMSCs) recover liver function in animal models with liver failure. Our initial findings revealed that human BMSCs improved liver function in hepatitis B patients with end stage liver disease. However, the susceptibility of BMSCs to HBV infection during induction toward hepatocytes remains unknown. We have assessed whether BMSCs‐derived hepatocyte‐like cells can function like liver cells and be infected by HBV. A new and efficient way to direct the differentiation of BMSCs into functional hepatocytes was developed. BMSCs obtained from hepatitis B patients were induced to differentiate into hepatocytes through exposure to HGF, FGF‐4, and EGF. After 6 days of exposure, BMSCs‐derived hepatocyte‐like cells that expressed a subset of hepatic genes and showed hepatic functions were obtained. HBV was used to infect the differentiated cells, and subsequently these cells were assayed for the presence of HBeAg, HBsAg, and HBV DNA. BMSCs proved resistant to HBV infection, both in vitro and during differentiation into hepatocytes in vitro. This demonstrates that BMSCs are resistant to HBV infection. BMSCs are viable for transplantation and should facilitate further research exploring the in vivo HBV‐resistance of the hepatocytes derived from BMSCs after transplantation, a characteristic that could form the basis for hepatocyte transplantation.
Women, gender equality, and diabetes
Authors: Hannan Carolyn
Published: January 2009

Discussion of women, gender equality, and diabetes should be placed in the context of United Nations mandates on women's health which highlight the need for equal access to information, prevention activities, services, and care across the life cycle. Gender differences and inequalities have been identified in relation to causes and consequences of diabetes and access to services and support between women and men, and among different groups of women. Appropriate gender‐sensitive policy responses, including research and data collection, need to be developed. The recent United Nations resolution on diabetes provides an opportunity to strengthen the focus on women and diabetes.