bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural durability criteria for commercial vehicle components from the self strengthening cast ausferrite nodular iron EN‐GJS‐800–8 (ADI) in comparison to the ferritic EN‐GJS‐400–15
Authors: Sonsino C. M. , Zinke R. , Heinrietz A. , Heim R. , Hanselka H. , Streicher M.
Published: October 2008

The structural durability of safety components in the chassis comprises not only the fatigue behaviour under cyclic variable amplitude service loading, but also its interaction with prestrains caused by special events and the rupture behaviour under impact loading due to misuse . From this background, the structural durability behaviour of Panhard rods made from ferritic cast nodular iron EN‐GJS‐400–15 was compared with the behaviour of rods made from the austempered EN‐GJS‐800–8.

The components investigated, Panhard rods and cast plugs, made from the austempered material revealed a higher impact resistance than the components made from the ferritic cast nodular iron. Due to their ausferrite microstructure, Panhard rods made from EN‐GJS‐800–8 display a significantly superior fatigue strength behaviour, especially under spectrum loading, and offer a potential for lightweight design. Prestrains do not affect the fatigue behaviour under variable amplitude loading and the plastic deformation of the component under impact loading can be increased by appropriate design reducing the stiffness in the shaft area and achieving a weight reduction by 15 %.
Material and fatigue life models for thermo‐mechanical loaded components
Authors: Eichlseder W. , Winter G. , Köberl H.
Published: October 2008

Today, specific material data, mainly from static material tests, are not sufficient to design parts of a product to assess lifetime behaviour, especially when local complex loading occurs like low cycle fatigue (LCF) and thermo mechanical fatigue (TMF). In this work, specimen tests are carried out under LCF and TMF loading with different materials, where mechanical and thermal properties are considered. The investigated materials are an aluminium alloy, cast iron, copper alloy and nickel. The TMF tests are performed by using a TMF test rig, designed by the Chair of Mechanical Engineering (AMB). The results of these tests allow a description of the material behaviour depending on the mechanical and thermal boundary conditions. Commercial Software for Finite Element Analysis (FEA) enables a fit with the test results to calculate stress and strain values for different loading conditions. These results are the input data for the final lifetime calculation. A number of approaches are given to determine the lifetime for the investigated materials. Finally, a special modified energy method – “unified energy approach” – is presented and compared with conventional approaches.
Tumor suppressor and oncogene actions of TGFβ1 occur early in skin carcinogenesis and are mediated by Smad3
Authors: Bae Dong‐Soon , Blazanin Nicholas , Licata Mathew , Lee Jessica , Glick Adam B.
Published: October 2008

Interactions between TGFβ1 and ras signaling pathways play an important role in cancer development. Here we show that in primary mouse keratinocytes, v‐rasHa does not block the early biochemical events of TGFβ1 signal transduction but does alter global TGFβ1 mediated gene expression in a gene specific manner. Expression of Smad3 dependent TGFβ1 early response genes and the TGFβ1 cytostatic gene expression response were not altered by v‐rasHa consistent with an intact TGFβ1 growth arrest. However, TGFβ1 and v‐rasHa cause significant alteration in genes regulating matrix remodeling as the TGFβ1 induction of extracellular matrix genes was blocked by v‐rasHa but specific matrix proteases associated with cancer progression were elevated. Smad3 deletion in keratinocytes repressed normal differentiation maker expression and caused expression of Keratin 8 a simple epithelial keratin and marker of malignant conversion. Smad3 was required for the TGFβ1 cytostatic response in v‐rasHa keratinocytes, but also for protease induction, keratinocyte attachment and migration. These results show that pro‐oncogenic activities of TGFβ1 can occur early in carcinogenesis before loss of its tumor suppressive function and that selective regulation rather than complete inactivation of Smad3 function may be crucial for tumor progression. © 2008 Wiley‐Liss, Inc.
A randomized controlled trial of movement strategies compared with exercise for people with Parkinson's disease
Authors: Morris Meg E. , Iansek Robert , Kirkwood Beth
Published: October 2008

This randomized controlled clinical trial was conducted to compare the effects of movement rehabilitation strategies and exercise therapy in hospitalized patients with idiopathic Parkinson's disease. Participants were randomly assigned to a group that received movement strategy training or musculoskeletal exercises during 2 consecutive weeks of hospitalization. The primary outcome was disability as measured by the Unified Parkinson's Disease Rating Scale, UPDRS (motor and ADL components). Secondary outcomes were balance, walking speed, endurance, and quality of life. Assessments were carried out by blinded testers at baseline, after the 2 weeks of treatment and 3 months after discharge. The movement strategy group showed improvements on several outcome measures from admission to discharge, including the UPDRS, 10 m walk, 2 minute walk, balance, and PDQ39. However, from discharge to follow up there was significant regression in performance on the 2 minute walk and PDQ39. For the exercise group, quality of life improved significantly during inpatient hospitalization and this was retained at follow‐up. Inpatient rehabilitation produces short term reductions in disability and improvements in quality of life in people with Parkinson's disease. © 2008 Movement Disorder Society
EPR studies of the dynamics and phase behaviour of dithiadiazolyl radicals derived from mesogenic precursors
Authors: Rawson Jeremy M. , Clarke Caroline S. , Bruce Duncan W.
Published: October 2008

A series of liquid‐crystalline materials based on 4‐substituted cyanobiphenyls, RC6H4C6H4CN (R = C5H11, C6H13, C7H15, C8H17 and C12H25, commonly referred to as 5CB, 6CB, 7CB, 8CB and 12CB, respectively) were functionalised to give the corresponding dithiadiazolyl organic radicals RC6H4C6H4CNSSN• (compounds 1•, 2•, 3•, 4• and 5•, respectively). EPR spectra of n‐C12H25C6H4C6H4CNSSN• (5•) reveal that it adopts a dimeric diamagnetic structure in the solid state with a small number of paramagnetic defect sites. Variable temperature electron paramagnetic resonance (EPR) studies reveal a thermally activated rotation about the molecular long axis at temperatures above 314 K. The energy barrier to rotation about the phenylene–dithiadiazolyl bond was estimated as 25 kJ mol−1 using density functional theory (DFT). At elevated temperatures thermal annealing was also observed, quenching the sample's paramagnetism. Copyright © 2008 John Wiley & Sons, Ltd.
Dynamic evacuation routes for personnel on a naval ship
Authors: Pérez‐Villalonga Francisco , Salmerón Javier , Wood Kevin
Published: October 2008

We propose a dynamic escape route system for emergency evacuation of a naval ship. The system employs signals that adapt to the causative contingency and the crew's physical distribution about the ship. A mixed‐integer nonlinear programming model, with underlying network structure, optimizes the evacuation process. The network's nodes represent compartments, closures (e.g., doors and hatches) and intersections, while arcs represent various types of passageways. The objective function integrates two potentially conflicting factors: average evacuation time and the watertight and airtight integrity of the ship after evacuation. A heuristic solves the model approximately using a sequence of mixed‐integer linear approximating problems. Using data for a Spanish frigate, with standard static routes specified by the ship's designers, computational tests show that the dynamic system can reduce average evacuation times, nearly 23%, and can improve a combined measure of ship integrity by up to 50%. In addition, plausible design changes to the frigate yield further, substantial improvements. Published 2008 Wiley Periodicals, Inc. Naval Research Logistics 2008
A new outranking‐based approach for assigning alternatives to ordered classes
Authors: Köksalan Murat , Mousseau Vincent , Özpeynirci Özgür , Özpeynirci Selin Bilgin
Published: October 2008

We consider the problem of assigning alternatives evaluated on several criteria into ordered categories C1,C2,…,Cp. This problem is known as the multi‐criteria sorting problem and arises in many situations such as classifying countries into different risk levels based on economical and socio‐political criteria, evaluating credit applications of bank customers. We are interested in sorting methods that are grounded on the construction of outranking relations. Among these, the Electre Tri method requires defining multidimensional profiles that represent the “frontier” separating consecutive categories Ch and Ch+1, and assigns an alternative to categories according to how it compares to each of the profiles. The explicit specification of the profiles of consecutive categories can be difficult for decision makers. We develop a new outranking based sorting method that does not require the explicit definition of profiles. We instead require the decision maker to assign a subset of reference alternatives to the categories. To assign the remaining alternatives, each such alternative is compared to reference alternatives, and assigned to categories accordingly. © 2008 Wiley Periodicals, Inc. Naval Research Logistics 2009
Optimizing the US Navy's combat logistics force
Authors: Brown Gerald G. , Carlyle W. Matthew
Published: October 2008

We study how changes to the composition and employment of the US Navy combat logistic force (CLF) influence our ability to supply our navy worldwide. The CLF consists of about 30 special transport ships that carry ship and aircraft fuel, ordnance, dry stores, and food, and deliver these to client combatant ships underway, making it possible for our naval forces to operate at sea for extended periods. We have modeled CLF operations to evaluate a number of transforming initiatives that simplify its operation while supporting an even larger number of client ships for a greater variety of missions. Our input is an employment schedule for navy battle groups of ships operating worldwide, extending over a planning horizon of 90–180 days. We show how we use optimization to advise how to sustain these ships. We have used this model to evaluate new CLF ship designs, advise what number of ships in a new ship class would be needed, test concepts for forward at‐sea logistics bases in lieu of conventional ports, demonstrate the effects of changes to operating policy, and generally try to show whether and how the CLF can support planned naval operations. Published 2008 Wiley Periodicals, Inc. Naval Research Logistics 2008
Noncooperative cost spanning tree games with budget restrictions
Authors: Bergantiños Gustavo , Lorenzo Leticia
Published: October 2008

We extend the noncooperative game associated with the cost spanning tree problem introduced by Bergantiños and Lorenzo (Math Method Oper Res 59(2004), 393–403) to situations where agents have budget restrictions. We study the Nash equilibria, subgame perfect Nash equilibria, and strong Nash equilibria of this game. © 2008 Wiley Periodicals, Inc. Naval Research Logistics 2008
A selective newsvendor approach to order management
Authors: Taaffe Kevin , Romeijn Edwin , Tirumalasetty Deepak
Published: October 2008

Consider a supplier offering a product to several potential demand sources, each with a unique revenue, size, and probability that it will materialize. Given a long procurement lead time, the supplier must choose the orders to pursue and the total quantity to procure prior to the selling season. We model this as a selective newsvendor problem of maximizing profits where the total (random) demand is given by the set of pursued orders. Given that the dimensionality of a mixed‐integer linear programming formulation of the problem increases exponentially with the number of potential orders, we develop both a tailored exact algorithm based on the L‐shaped method for two‐stage stochastic programming as well as a heuristic method. We also extend our solution approach to account for piecewise‐linear cost and revenue functions as well as a multiperiod setting. Extensive experimentation indicates that our exact approach rapidly finds optimal solutions with three times as many orders as a state‐of‐the‐art commercial solver. In addition, our heuristic approach provides average gaps of less than 1% for the largest problems that can be solved exactly. Observing that the gaps decrease as problem size grows, we expect the heuristic approach to work well for large problem instances. © 2008 Wiley Periodicals, Inc. Naval Research Logistics 2008
Dynamic inventory management with cash flow constraints
Authors: Chao Xiuli , Chen Jia , Wang Shouyang
Published: October 2008

In this article, we consider a classic dynamic inventory control problem of a self‐financing retailer who periodically replenishes its stock from a supplier and sells it to the market. The replenishment decisions of the retailer are constrained by cash flow, which is updated periodically following purchasing and sales in each period. Excess demand in each period is lost when insufficient inventory is in stock. The retailer's objective is to maximize its expected terminal wealth at the end of the planning horizon. We characterize the optimal inventory control policy and present a simple algorithm for computing the optimal policies for each period. Conditions are identified under which the optimal control policies are identical across periods. We also present comparative statics results on the optimal control policy. © 2008 Wiley Periodicals, Inc. Naval Research Logistics 2008
Ventricular cerebrospinal fluid lactate is increased in chronic fatigue syndrome compared with generalized anxiety disorder: an in vivo 3.0 T 1H MRS imaging study
Authors: Mathew Sanjay J. , Mao Xiangling , Keegan Kathryn A. , Levine Susan M. , Smith Eric L. P. , Heier Linda A. , Otcheretko Viktor , Coplan Jeremy D. , Shungu Dikoma C.
Published: October 2008

Chronic fatigue syndrome (CFS) is a controversial diagnosis because of the lack of biomarkers for the illness and its symptom overlap with neuropsychiatric, infectious, and rheumatological disorders. We compared lateral ventricular volumes derived from tissue‐segmented T1‐weighted volumetric MRI data and cerebrospinal fluid (CSF) lactate concentrations measured by proton MRS imaging (1H MRSI) in 16 subjects with CFS (modified US Centers for Disease Control and Prevention criteria) with those in 14 patients with generalized anxiety disorder (GAD) and in 15 healthy volunteers, matched group‐wise for age, sex, body mass index, handedness, and IQ. Mean lateral ventricular lactate concentrations measured by 1H MRSI in CFS were increased by 297% compared with those in GAD (P < 0.001) and by 348% compared with those in healthy volunteers (P < 0.001), even after controlling for ventricular volume, which did not differ significantly between the groups. Regression analysis revealed that diagnosis accounted for 43% of the variance in ventricular lactate. CFS is associated with significantly raised concentrations of ventricular lactate, potentially consistent with recent evidence of decreased cortical blood flow, secondary mitochondrial dysfunction, and/or oxidative stress abnormalities in the disorder. Copyright © 2008 John Wiley & Sons, Ltd.
Probing the viscoelastic properties of brominated isobutylene‐co‐p‐methylstyrene rubber/tackifier blends using a rubber process analyzer
Authors: Kumar K. Dinesh , Gupta Sanjiv , Sharma B.B. , Tsou Andy H. , Bhowmick Anil K.
Published: October 2008

The viscoelastic behavior of brominated isobutylene‐co‐p‐methylstyrene (BIMS) rubber/hydrocarbon resin blends and BIMS/phenol formaldehyde resin blends was studied with the use of a rubber process analyzer. Dynamic mechanical analysis and scanning electron microscopy were used to evaluate the compatibility between the BIMS/tackifier blends. Strain sweep tests at temperature below the softening point of the tackifiers showed the formation of resin–resin networks in the incompatible BIMS/phenolic resin blends. However, resin–resin network was not prominent in the case of the compatible BIMS/hydrocarbon resin blends. Frequency sweep tests were performed at the strain amplitude within the linear region at several temperatures and the variations of shear storage modulus, G′ and complex viscosity, η* against frequency were recorded. The tackifying resins modified the viscoelastic properties of the BIMS rubber by reducing the storage modulus at lower frequency and by increasing the storage modulus at higher frequencies. However, this action was found to be highly dependent on (a) rubber‐tackifier compatibility, (b) blend proportions, and (c) test temperature. Furthermore, stress relaxation measurements of the BIMS/tackifier blends at temperature below the softening point of the tackifiers showed longer period of relaxation for the incompatible BIMS/phenolic resin blends. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
Shunting problems due to sub‐micron pinholes in evaporated solid‐phase crystallised poly‐Si thin‐film solar cells on glass
Authors: Kunz O. , Wong J. , Janssens J. , Bauer J. , Breitenstein O. , Aberle A.G.
Published: October 2008

Recent progress in the metallisation of poly‐silicon thin‐film solar cells on glass, created by solid phase crystallisation (SPC) of evaporated amorphous silicon (EVA), revealed that shunting through sub‐micron holes (density 100–200 mm−2) in the films causes severe shunting problems when the air‐side metal contact is deposited onto these diodes, by creating effective shunting paths between the two highly doped layers of EVA cells. We present evidence of these pinholes by optical transmission and focussed ion beam (FIB) microscopic images and confirm the point‐like pinhole shunts using lock‐in thermographic images. The latter revealed that the Al rear electrode induces strong ohmic shunts below the grid lines and a high density of weak non‐linear shunts away from the grid lines. Two distinctly different approaches are shown to reduce the shunting problem to a negligible level: (i) to contact only a small fraction of the rear Si surface via a point contacting scheme, whereby the metal layer needs to be thin (<1 µm) and the fractional area coverage small (<5%), and (ii) to deposit line contacts in a bifacial interdigitated scheme, whereby a thick layer of metal is deposited followed by a wet‐chemical etching step that effectively reduces shunting by preferentially etching away the shunting paths. Test devices with an area of 1 cm2achieve pseudo fill factors (pFF) of above 75% and diode ideality factors of below 1·3, demonstrating that the proposed methods are well suited for the metallisation of the rear surface of EVA solar cells. Copyright © 2008 John Wiley & Sons, Ltd.
Are psychedelic drug treatments seeing a comeback in psychiatry?
Authors: St John Sessa Benjamin
Published: October 2008

After a hiatus of nearly 40 years, psychedelic drugs (or hallucinogens) are being increasingly researched as possible adjuncts to psychotherapy for treatment‐resistant anxiety disorders and addictions.This research offers an exciting future for this class of drugs whose image has been tarnished by recreational use since the 1960s.Through cautious and evidence‐based studies, these medications could be finding their way back to where they began their lives: as valid and effective tools for clinical medicine and neuroscientific research. Copyright © 2008 Wiley Interface Ltd
Circadin: a new option in sleep disorders
Authors: Greener Mark
Published: October 2008

Circadin ‐ a prolonged‐release formulation containing 2mg melatonin ‐ offers a promising short‐term treatment for primary insomnia that is characterised by poor sleep quality in patients aged 55 years or over. Medical writer, Mark Greener, reviews this new addition to the sleep treatment armamentarium. Copyright © 2008 Wiley Interface Ltd
Advances and frustrations in paediatric psychiatry ‐ Interview with Professor Sir Michael Rutter
Authors: Greener Mark
Published: October 2008

Rutter's Child and Adolescent Psychiatry is one of the best‐established and highly regarded textbooks covering paediatric psychiatry. To mark the publication of the 5th edition of this influential volume, Progress talked to chief editor Professor Sir Michael Rutter, from the Institute of Psychiatry. Professor Rutter discussed some of the advances that prompted the new edition;his concerns regarding the disconnect between science and service provision, and his belief that clinicians and bureaucrats need to view mental disorders from a life course perspective. Copyright © 2008 Wiley Interface Ltd
British Association for Psychopharmacology Summer meeting: Can't sleep, won't sleep – But why not?
Authors: Anaokar Maya
Published: October 2008

Circadian rhythm is no longer an unknown black box but an increasingly well‐understood aspect of human biology that plays a crucial role in sleep. Medical writer, Maya Anaokar, reports from a satellite symposium organised by Lundbeck at the British Association for Psychopharmacology's Summer meeting in July. Copyright © 2008 Wiley Interface Ltd
Predictive QSPR modeling of the acidic dissociation constant (pKa) of phenols in different solvents
Authors: Roy Kunal , Popelier Paul L. A.
Published: October 2008

Given the importance of ionization constant (pKa) of phenols in explaining the mechanism of their toxicity, it is of interest to develop theoretical models for the prediction of pKa values of phenols in different solvent systems. In the present communication, we developed predictive QSPR models for pKa values of substituted phenols in seven different solvent systems such as water, dimethyl sulfoxide (DMSO), methanol, dimethylformamide (DMF), acetonitrile (AN), isopropanol, and tert‐butanol using quantum topological molecular similarity (QTMS) descriptors. The data set was divided into training and test sets, and models were developed using partial least squares (PLS) regression from the training set. The predictive potential of the developed models was assessed by the prediction of pKa values of the test set compounds. Root mean square error of prediction (RMSEP) values were used as objective function for selection of the best models in different solvent systems. Good predictive models were developed in all solvent systems except isopropanol. Considering all seven solvent systems, distance descriptors give consistently good results whereas ellipticity descriptors are of less importance. Moreover, plots of ‘variable importance in the projection’ (VIP) for the best models highlight the importance of the bond connecting the phenolic oxygen to the aromatic ring. This suggests the diagnostic nature of QTMS descriptors in identifying the reaction center in acidic dissociation of phenols. Copyright © 2008 John Wiley & Sons, Ltd.
A [‐2]proPSA‐based artificial neural network significantly improves differentiation between prostate cancer and benign prostatic diseases
Authors: Stephan Carsten , Kahrs Anna‐Maria , Cammann Henning , Lein Michael , Schrader Mark , Deger Serdar , Miller Kurt , Jung Klaus
Published: October 2008

Background

The aim of this study was to combine the new automated Access [‐2]proPSA (p2PSA) assay with a percent free PSA (%fPSA) based artificial neural network (ANN) or logistic regression (LR) model to enhance discrimination between patients with prostate cancer (PCa) and with no evidence of malignancy (NEM) and to detect aggressive PCa.

Methods

Sera from 311 PCa patients and 275 NEM patients were measured with the p2PSA, total PSA (tPSA) and free PSA (fPSA) assays on Access immunoassay technology (Beckman Coulter, Fullerton, CA) within the 0–30 ng/ml tPSA range. Four hundred seventy‐five patients (264 PCa, 211 NEM) had a tPSA of 2–10 ng/ml. LR models and leave‐one‐out (LOO) ANN models with Bayesian regularization by using tPSA, %fPSA, p2PSA/fPSA (%p2PSA), age and prostate volume were constructed and compared by receiver‐operating characteristic (ROC) curve analysis.

Results

The ANN and LR model each utilizing %p2PSA, %fPSA, tPSA and age, but without prostate volume, reached the highest AUCs (0.85 and 0.84) and best specificities (ANN: 62.1% and 45.5%; LR: 53.1% and 41.2%) compared with tPSA (22.7% and 11.4%) and %fPSA (45.5% and 26.1%) at 90% and 95% sensitivity. The %p2PSA furthermore distinguished better than tPSA and %fPSA between pT2 and pT3, and Gleason sum <7 and ≥7 PCa.

Conclusions

The automated p2PSA assay offers a new tool to improve PCa detection, and especially aggressive PCa detection. Incorporation of %p2PSA into an ANN and LR model further enhances the diagnostic accuracy to differentiate between malignant and non‐malignant prostate diseases. Prostate 69: 198–207, 2009. © 2008 Wiley–Liss, Inc.
Dihydrotestosterone sensitises LNCaP cells to death induced by epigallocatechin‐3‐gallate (EGCG) or an IGF‐i receptor inhibitor
Authors: Thomas Francis , Patel Suril , Holly Jeff M.P. , Persad Raj , Bahl Amit , Perks Claire M.
Published: October 2008

BACKGROUND

Compelling evidence has accumulated for chemopreventive effects for the active component of green tea Epigallocatechin‐3‐Gallate (EGCG) particularly for prostate cancer (CaP).

METHODS

We have assessed interactions between the effects of EGCG and two main regulators of prostate cell function, dihydrotestosterone (DHT) and insulin‐like growth factor‐1 (IGF‐I). Using LNCaP (androgen‐sensitive), PC3 and DU145 (androgen‐resistant) CaP cell lines, we assessed the effect of EGCG alone on growth (0–200 µM) and on cell death (0–50 µM).

RESULTS

EGCG decreased the proliferation of all the CaP cancer cells in a dose‐dependent manner with an increase in apoptosis from 30 to 50 µM. With DU145 cells, a sub‐apoptotic dose of EGCG (10–20 µM) reduced IGF‐induced growth. With LNCaP cells, a sub‐apoptotic dose of EGCG (8 µM) switched DHT from a growth promoter to a growth inhibitor. A similar reversal of DHT effect was seen in the presence of an IGF‐I receptor inhibitor, AG1024 (1 µM). These responses appeared to be due to DHT sensitizing the cells to apoptosis by EGCG and AG1024 (P < 0.01 and P < 0.001 respectively).

CONCLUSIONS

Our data suggests that both green tea and AG1024 are effective in inhibiting cell growth and inducing death in CaP cells but the effects of both are more effective in the presence of androgen. Prostate 69: 219–224, 2009. © 2008 Wiley–Liss, Inc.
G protein inactive and active forms investigated by simulation methods
Authors: Khafizov Kamil , Lattanzi Gianluca , Carloni Paolo
Published: October 2008

Molecular dynamics and computational alanine scanning techniques have been used to investigate G proteins in their inactive state (the Gαi1β1γ2 heterotrimer) as well as in their empty and monomeric active states (Gαi1 subunit). We find that: (i) the residue Q204 of Gαi1 plays a key role for binding Gβ1γ2 and is classified among the most relevant in the interaction with a key cellular partner, the so‐called regulator of G protein signaling protein. The mutation of this residue to L, which is observed in a variety of diseases, provides still fair stability to the inactive state because of the formation of van der Waals interactions. (ii) The empty state turns out to adopt some structural features of the active one, including a previously unrecognized rearrangement of a key residue (K46). (iii) The so‐called Switch IV region increases its mobility on passing from the empty to the active state, and, even more, to the inactive state. Such change in mobility could be important for its several structural and functional roles. (iv) A large scale motion of the helical domain in the inactive state might be important for GDP release upon activation by GPCR, consistently with experimental data. Proteins 2009. © 2008 Wiley‐Liss, Inc.
Fullerene solubility–current density relationship in polymer solar cells
Authors: Renz Joachim A. , Troshin Pavel A. , Gobsch Gerhard , Razumov V. F. , Hoppe Harald
Published: October 2008

During the last decade polymer solar cells have undergone a steady increase in overall device efficiency. To date, essential efficiency improvements of polymer–fullerene solar cells require the development of new materials. Whilst most research efforts aim at an improved or spectrally extended absorption of the donor polymer, not so much attention has been paid to the fullerene properties themselves. We have investigated a number of structurally related fullerenes, in order to study the relationship between chemical structure and resulting polymer–fullerene bulk heterojunction photovoltaic properties. Our study reveals a clear connection between the fullerene solubility as material property on one hand and the solar cells short circuit photocurrent on the other hand. The tendency of the less soluble fullerene derivates to aggregate was accounted for smaller current densities in the respective solar cells. Once a minimum solubility of approx. 25 mg/ml in chlorobenzene was overcome by the fullerene derivative, the short circuit current density reached a plateau, of about 8–10 mA/cm2. Thus the solubility of the fullerene derivative directly influences the blend morphology and displays an important parameter for efficient polymer–fullerene bulk heterojunction solar cell operation. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The relationship between geomorphic river adjustment and management actions over the last 50 years in the Upper Hunter Catchment, NSW, Australia
Authors: Spink Alexandra , Fryirs Kirstie , Brierley Gary
Published: October 2008

The installation of 517 river works in the upper Hunter catchment, New South Wales over the last 50 years is linked to geomorphic river adjustment and flood history at catchment and reach scales. Nineteen types of works are classified into three categories consisting of engineering, heavy machinery and vegetation works. Since 1952, a transition in techniques has been detected from engineering‐based approaches, to river training/maintenance, to more ecosystem‐based approaches. From the 1950s to the mid‐1980s extensive river engineering was undertaken. Projects were concentrated along laterally unconfined rivers and were generally implemented after major phases of geomorphic river adjustment. Neither the type of river nor the type of river adjustment guided the implementation of differing management techniques or their distribution in the catchment. A blanket approach was adopted, applying the same types of works across all types of river. Emphasis was placed upon concerns for bank instability rather than bed instability. Hence in many cases, river works addressed the symptoms (i.e. bank erosion) rather than the underlying causes of river change (i.e. bed incision). Since the mid 1980s, techniques have evolved towards vegetation‐based procedures. The development of more effective river rehabilitation programmes requires that greater consideration is given to proactive strategies which build upon an understanding of geomorphic river adjustments at the catchment scale. Copyright © 2008 John Wiley & Sons, Ltd.
Carrier phase recovery for turbo‐coded systems with pre‐coded GMSK modulation
Authors: Wu Zhuo , Zhou Liang , Burr Alister G.
Published: October 2008

A carrier phase recovery scheme suited for turbo‐coded systems with pre‐coded Gaussian minimum shift keying (GMSK) modulation is proposed and evaluated in terms of bit‐error‐rate (BER) performance. This scheme involves utilizing the extrinsic information obtained from the turbo‐decoder to aid an iterative carrier phase estimation process, based on a maximum‐likelihood (ML) strategy. The phase estimator works jointly with the turbo‐decoder, using the updated extrinsic information from the turbo‐decoder in every iterative decoding. A pre‐coder is used to remove the inherent differential encoding of the GMSK modulation. Two bandwidths of GMSK signals are considered: BT=0.5 and 0.25, which are recommended by the European Cooperation for Space Standardization (ECSS). It is shown that the performance of this technique is quite close to the perfect synchronized system within a wide range of phase errors. This technique is further developed to recover nearly any phase error in [−π,+π] by increasing the number of phase estimators and joint decoding units. This, however, will increase the complexity of the system. Copyright © 2008 John Wiley & Sons, Ltd.
Opportunity discovery, entrepreneurial action, and economic organization
Authors: Klein Peter G.
Published: October 2008

This article reviews and critiques the opportunity discovery approach to entrepreneurship and argues that entrepreneurship can be more thoroughly grounded, and more closely linked to more general problems of economic organization by adopting the Cantillon‐Knight‐Mises understanding of entrepreneurship as judgment. The article begins by distinguishing among occupational, structural, and functional approaches to entrepreneurship and distinguishing among two influential interpretations of the entrepreneurial function—discovery and judgment. It turns next to the contemporary literature on opportunity identification and argues that this literature misinterprets Kirzner's instrumental use of the discovery metaphor and mistakenly makes opportunities the unit of analysis. The article then describes an alternative approach in which investment is the unit of analysis and link this approach to Austrian capital theory. I close with some applications to organizational form and entrepreneurial teams. Copyright © 2008 Strategic Management Society.
A Bayesian multilevel model for estimating the diet/disease relationship in a multicenter study with exposures measured with error: The EPIC study
Authors: Ferrari Pietro , Carroll Raymond J. , Gustafson Paul , Riboli Elio
Published: October 2008

In a multicenter study, the overall relationship between diet and cancer risk can be broken down into: (a) within‐center relationships, which reflect the relationships at the individual level in each of the centers, and (b) a between‐center relationship, which captures the association between exposure and disease risk at the aggregate level. In this work, we propose the use of a Bayesian multilevel model that takes into account the within‐ and between‐center levels of evidence, using information at the individual and aggregate level. Correction for measurement error is performed in order to correct for systematic between‐center measurement error in dietary exposure, and for attenuation biases in relative risk estimates within centers. The estimation of the parameters is carried out in a Bayesian framework using Gibbs sampling. The model entails a measurement, an exposure, and a disease component. Within the European Prospective Investigation into Cancer and Nutrition (EPIC) the association between lipid intake, assessed through dietary questionnaire and 24‐hour dietary recall, and breast cancer incidence was evaluated. This analysis involved 21 534 women and 334 incident breast cancer cases from the EPIC calibration study. In this study, total energy intake was positively associated with breast cancer incidence at the aggregate level, whereas no effect was observed for fat. At the individual level, height was positively related to breast cancer incidence, whereas a weaker association was observed for fat. The use of multilevel models, which constitute a very powerful approach to estimating individual vs aggregate levels of evidence should be considered in multicenter studies. Copyright © 2008 John Wiley & Sons, Ltd.
Modelling of viral dynamics in hepatitis B and hepatitis C clinical trials
Authors: Sypsa Vana , Hatzakis Angelos
Published: October 2008

In the recent years, studies of hepatitis B (HBV) and hepatitis C virus (HCV) dynamics have drawn great attention as they provide insight into the process of virus elimination/production and of infected cells decay during antiviral treatment. Estimates of viral dynamic parameters may be used to determine the lifetime of HCV/HBV virions and of infected cells, to estimate how long patients need to be treated and to evaluate antiviral therapies. The implementation of viral dynamics studies is difficult because they involve an intensive blood‐sampling schedule and subsequent viral load quantification. In the majority of these studies, a model proposed by Neumann et al. (Science 1998; 282:103–107) is used under various assumptions, such as ignoring the delay in initial viral load decay, assuming time‐constant treatment efficacy in reducing virion production and/or complete blocking of new infections, etc. However, only recently the effect of some of these assumptions on the estimated parameters has been evaluated. In this paper we provide a detailed review of the model, its underlying assumptions as well as the assumptions usually made by researchers during the design and analysis of viral dynamics studies. Then, we investigate the effect of these assumptions on the estimated parameters using simulations and draw useful conclusions concerning the analysis of these studies. Real data examples from a clinical trial on hepatitis B are provided as illustrations. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of Sago Starch Addition and Steaming Time on Making Cassava Cracker (Keropok)
Authors: Tongdang Taewee , Meenun Mutita , Chainui Janphen
Published: October 2008

This work was aimed at investigating the effects of steaming time and different fractions of sago starch (0, 6, 12, 18 and 24%) in mixtures with cassava starch on the properties of crackers as compared to cassava crackers. In the hydrothermal process, the steaming period was varied from 25 to 120 min. The properties of raw starches, half‐finished crackers (HFC) and puffed crackers (PC) were determined. Raw cassava starch had lower amylose content, smaller granule size, lower gelatinization and lower swelling power than sago starch. The properties of the raw starch mixtures varied according to the mixing proportions. Both sago starch content and steaming time influenced cracker quality, especially its expansion, which was related to the degree of gelatinization (DG). Increasing sago starch content caused decreased DG of HFC and hence decreased cracker expansion. Two groups of HFC were obtained; low DG (55–65%, 25‐45 min steaming time) and high DG (>80%, 60‐120 min steaming time) HFC. Generally the expansion increased as the DG increased – however, a too long steaming period (>75 min) again reduced expansion, apparently the thinner starch gel allowed collapse of the air cells. No treatment gave complete gelatinization; which could be due to insufficient water for starch to gelatinize.
Composition and Film Properties of Temperature Responsive, Hydrophobically Modified Potato Starch
Authors: Andersson Caisa , Jonhed Anna , Järnström Lars
Published: October 2008

The film‐forming properties of hydrophobically modified potato starch were studied to optimize coating and surface sizing formulations for improvement of barrier properties of paper and paperboard. The spontaneous fractionation of a potato starch hydrophobically modified with a quaternary dodecylammonium chloride resulted in an amylose‐rich precipitate with properties differing from those of the original starch. Film formation was investigated in the presence of glycerol and poly(vinyl alcohol) plasticizers. Anti‐plasticization was found to occur at low and intermediate plasticizer levels but highly flexible, continuous films were obtained when 30 parts of plasticizer were added to 100 parts of dry starch. The highest transparency and greatest flexibility were obtained with glycerol, while the hydrophobic film properties were maintained with poly(vinyl alcohol). A study of the glass transition temperatures and melting behavior of starch‐plasticizer films by differential scanning calorimetry gave useful information about the crystallinity of the films.
Influence of Chain Length on α‐1,4‐D‐Glucan Recrystallization and Slowly Digestible Starch Formation
Authors: Robin Frédéric , Mérinat Sylvie , Simon Agnès , Lehmann Undine
Published: October 2008

Short‐chain α‐(1,4)‐D‐glucan samples were generated by debranching of potato amylopectin and fractionation on gel permeation chromatography. The collected fractions were gathered to generate two samples with an average DPn of 32 and 42, respectively. The samples were recrystallized at −80 and 1°C for three days (10%, w/w) and the resulting structures and related digestibility were assessed. The results revealed that the slowly digestible starch (SDS) content was affected by both chain length and recrystallization temperature. The highest SDS level (49%) was obtained at −80°C from the sample with the lowest average DPn. Its structure showed B‐type polymorphic crystallites with a substantial amorphous part and a melting temperature of 85°C. Such a melting temperature was close to that already reported in the literature and appears characteristic of recrystallized SDS structures.
Physical and Mechanical Properties of Durum Wheat (Triticum durum) Starch Films Prepared with A‐ and B‐type Granules
Authors: Montaño‐Leyva Beatriz , Torres‐Chávez Patricia , Ramírez‐Wong Benjamín , Plascencia‐Jatomea Maribel , Brown‐Bojórquez Francisco
Published: October 2008

The use of starch for the production of biodegradable materials has been increasing. Wheat is an important source, however, durum wheat starch and its separated granular components had not been evaluated for this purpose. The aim of this study was to evaluate the physical and mechanical properties of durum wheat starch films when prepared with a distribution of different granular‐sized starches (A‐ and B‐type). Starch was isolated, and the A and B populations of granules were separated. Films were prepared by casting. Glycerol (G) was used as a plasticizer in concentrations of 25% and 40%, respectively. Starch films were evaluated using scanning electron microscopy (SEM), mechanical properties (tensile strength, TS, elongation at break, E, elastic modulus, EM), solubility, and X‐ray diffraction (XRD). Durum wheat starch films were transparent, flexible, and, according to SEM, highly homogeneous. Films prepared with 25% G showed brittle material behavior (TS = 42–50 MPa, E = 1.4–2.7%, and EM = 31–34 MPa), whereas those prepared with 40% G had ductile material characteristics (TS = 11–17 MPa, E = 4–41%, and EM = 4–11.3 MPa). These mechanical properties of the films were significantly affected by the glycerol concentration and the starch granule type used. The film solubility was low when compared to those reported in other studies. It increased with increasing plasticizer concentration. According to the XRD, the films showed a semi‐crystalline structure.
The future of zoo biology
Authors: Wharton Dan
Published: October 2008

The science of zoo biology and the journal of the same name are appropriately perceived as central to the issues that zoological gardens must address in managing large collections of hundreds of different species of animals. However, zoos are also cultural institutions that are seeking relevance in wildlife conservation by reaching out to their enormous audiences collectively numbered in the hundreds of millions worldwide. This article suggests that if zoos are to be effective in realizing significant conservation outcomes, they will need to engage the much broader range of sciences in developing institutionally compatible conservation agendas that do not rest on untested assumptions. Some of the research questions that zoos might ask themselves are provided as examples. Zoo Biol 27:498–504, 2008. © 2008 Wiley‐Liss, Inc.
Prolonged Hospital Stay After Parathyroidectomy for Secondary Hyperparathyroidism
Authors: Cheng Shih‐Ping , Liu Chien‐Liang , Chen Han‐Hsiang , Lee Jie‐Jen , Liu Tsang‐Pai , Yang Tsen‐Long
Published: October 2008

Background

Protracted hypocalcemia is the most common complication after parathyroidectomy for secondary hyperparathyroidism. Several parameters have been identified to predict the degree of postoperative hypocalcemia. The purpose of this study was to determine whether there were any factors associated with prolonged hospitalization in these patients.

Methods

A total of 81 consecutive patients with end‐stage renal disease and advanced secondary hyperparathyroidism who underwent parathyroidectomy between January 2004 and December 2006 were studied. The postoperative calcium infusion protocol and discharge criteria were standardized. Clinical variables were compared between patients with a shorter or longer postoperative stay.

Results

The mean postoperative hospital stay was 5.6 days. Preoperative alkaline phosphatase levels were significantly higher in patients with a longer stay (p = 0.035). In a linear regression model, the postoperative length of stay was moderately but significantly correlated with preoperative alkaline phosphatase levels (R2 = 0.254; p < 0.001). Receiver operating characteristic analysis showed a significant area under the curve (0.678; 95% confidence interval 0.550–0.805; p = 0.014). With a cutoff of preoperative alkaline phosphatase levels at 200 IU/L, the sensitivity was 0.57 and the specificity was 0.59 for predicting a prolonged stay.

Conclusions

A high preoperative alkaline phosphatase level is significantly associated with prolonged hospital stay in patients undergoing parathyroidectomy for secondary hyperparathyroidism.
Neighborhood Effects Examined Through the Lens of Residential Mobility Programs
Authors: Keels Micere
Published: October 2008

Although researchers have consistently found that neighborhoods matter, relatively little is known about the processes through which neighborhood‐level characteristics influence individual outcomes, and whether interventions targeting improving neighborhood characteristics will be beneficial for children. I examine whether relocating from high‐ to low‐poverty neighborhoods affected low‐income Black children's exposure to promotive developmental experiences. Participating families voluntarily relocated from high‐poverty, minority segregated, inner‐city Chicago neighborhoods to mostly White, low‐poverty, suburban and Chicago neighborhoods. Data come from retrospective qualitative interviews with 22 Gautreaux One families an average of 15 years after initial relocation, and from interviews with 43 Gautreaux Two families as they relocated into their new communities. I find that children primarily benefited from the institutional versus the social interaction resources in their new neighborhoods. Furthermore, suburban placement was key in facilitating children's access to higher quality resources.
Locating the Extrema of Fungible Regression Weights
Authors: Waller Niels G. , Jones Jeff A.
Published: October 2008

In a multiple regression analysis with three or more predictors, every set of alternate weights belongs to an infinite class of “fungible weights” (Waller, Psychometrica, in press) that yields identical SSE (sum of squared errors) and R2 values. When the R2 using the alternate weights is a fixed value, fungible weights (ai) that yield the maximum or minimum cosine with an OLS weight vector (b) are called “fungible extrema.” We describe two methods for locating fungible extrema and we report R code (R Development Core Team, 2007) for one of the methods. We then describe a new approach for populating a class of fungible weights that is derived from the geometry of alternate regression weights. Finally, we illustrate how fungible weights can be profitably used to gauge parameter sensitivity in linear models by locating the fungible extrema of a regression model of executive compensation (Horton & Guerard, Commun. Stat. Simul. Comput. 14:441–448, 1985).