bluuebunny/crossref_metadata_2025 huggingface dataset:
Wavelets invariant under finite reflection groups
Authors: Bernardes G. , Bernstein S. , Cerejeiras P. , Kähler U.
Published: August 2009

In this paper we use approximate identities in the Dunkl setting in order to construct spherical Dunkl wavelets, which do not involve the knowledge of the intertwining operator, the Dunkl translation or of the Dunkl transform. The practicality of the proposed approach will be shown with the example of Abel‐Poisson wavelets. Copyright © 2009 John Wiley & Sons, Ltd.
Assessment of myocardial blood flow (MBF) in humans using arterial spin labeling (ASL): Feasibility and noise analysis
Authors: Zun Zungho , Wong Eric C. , Nayak Krishna S.
Published: August 2009

Arterial spin labeling (ASL) is a powerful tool for the quantitative measurement of tissue blood flow, and has been extensively applied to the brain, lungs, and kidneys. ASL has been recently applied to myocardial blood flow (MBF) measurement in small animals; however, its use in humans is limited by inadequate signal‐to‐noise ratio (SNR) efficiency and timing restrictions related to cardiac motion. We present preliminary results demonstrating MBF measurement in humans, using cardiac‐gated flow‐sensitive alternating inversion recovery (FAIR) tagging and balanced steady‐state free precession (SSFP) imaging at 3T, and present an analysis of thermal and physiological noise and their impact on MBF measurement error. Measured MBF values in healthy volunteers were 1.36 ± 0.40 ml/ml/min at rest, matching the published literature based on quantitative 13N‐ammonia positron emission tomography (PET), and increased by 30% and 29% with passive leg elevation and isometric handgrip stress, respectively. With thermal noise alone, MBF can be quantified to within ± 0.1 ml/ml/min with 85.5% confidence, for 3.09 cm3 regions averaged over 6 breath‐holds. This study demonstrates the feasibility of quantitative assessment of myocardial blood flow in humans using ASL, and identifies SNR improvement and the reduction of physiological noise as key areas for future development. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Spin‐locked balanced steady‐state free‐precession (slSSFP)
Authors: Witschey Walter R.T. , Borthakur Ari , Elliott Mark A. , Magland Jeremy , McArdle Erin L. , Wheaton Andrew , Reddy Ravinder
Published: August 2009

A spin‐locked balanced steady‐state free‐precession (slSSFP) pulse sequence is described that combines a balanced gradient‐echo acquisition with an off‐resonance spin‐lock pulse for fast MRI. The transient and steady‐state magnetization trajectory was solved numerically using the Bloch equations and was shown to be similar to balanced steady‐state free‐precession (bSSFP) for a range of T2/T1 and flip angles, although the slSSFP steady‐state could be maintained with considerably lower radio frequency (RF) power. In both simulations and brain scans performed at 7T, slSSFP was shown to exhibit similar contrast and signal‐to‐noise ratio (SNR) efficiency to bSSFP, but with significantly lower power. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Robust quantification of contrast agent (CA) concentration with magnetic field correlation (MFC) imaging
Authors: Patil Vishal , Johnson Glyn , Jensen Jens H.
Published: August 2009

Contrast‐enhanced perfusion studies of the brain by means magnetic resonance imaging (MRI) are used to estimate a number of important brain tissue parameters, including cerebral blood flow and volume. In order to calculate these parameters, the contrast agent (CA) concentration must first be estimated. This is usually accomplished by measurement of a nuclear magnetic resonance (NMR) relaxation rate with the assumption of a linear relationship between the rate and the CA concentration. However, such a linear relationship does not necessarily hold in biological tissues due to compartmentalization of the CA in either the intravascular or extracellular spaces. Here we propose an alternative MRI method of CA quantification based on measurement of the magnetic field correlation (MFC), which is theoretically predicted to have a robust quadratic dependence on the CA concentration even when the CA is compartmentalized. In this study, CA concentration estimation by means of MFC is shown to be more accurate than established methods based on relaxation rates in yeast cell suspensions. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
Inductively coupled helmholtz coil on a dedicated imaging platform for the in vivo1H‐MRS measurement of intramyocellular lipids in the hind leg of rats
Authors: Neumaier Michael , Niessen Heiko G. , Kaulisch Thomas , Stiller Detlef
Published: August 2009

Skeletal muscle triglycerides are markers for insulin resistance in type 2 diabetes. Recently, MR spectroscopy was adapted for in vivo measurement of triglycerides in animal models and for the characterization of new therapeutic approaches. Because of small MR spectroscopy voxel sizes used in skeletal muscles, surface coils are used for signal reception. Furthermore, to obtain well‐resolved and undistorted lipid spectra, muscle fibers must be aligned parallel to the magnetic field. Consequently, to achieve a high signal‐to‐noise ratio and spectral quality, a coil setup must combine high sensitivity with a reliable and reproducible positioning of muscle and voxel. These demands are difficult to match using surface coils. Here, a coil platform is described, which uses inductively coupled Helmholtz coil setup combined with a leg retainer system for rats. The new system allows for measurement of intramyocellular lipids with high signal‐to‐noise ratio and for significantly improved animal handling, positioning, and throughput. Magn Reson Med, 2009. © 2009 Wiley‐Liss, Inc.
A branch‐and‐price‐based large neighborhood search algorithm for the vehicle routing problem with time windows
Authors: Prescott‐Gagnon Eric , Desaulniers Guy , Rousseau Louis‐Martin
Published: August 2009

Given a fleet of vehicles assigned to a single depot, the vehicle routing problem with time windows (VRPTW) consists of determining a set of feasible vehicle routes to deliver goods to a set of customers while minimizing, first, the number of vehicles used and, second, total distance traveled. A large number of heuristic approaches for the VRPTW have been proposed in the literature. In this article, we present a large neighborhood search algorithm that takes advantage of the power of branch‐and‐price which is the leading methodology for the exact solution of the VRPTW. To ensure diversification during the search, this approach uses different procedures for defining the neighborhood explored at each iteration. Computational results on the Solomo's and the Gehring and Homberge's benchmark instances are reported. Compared to the best known methods, the proposed algorithm produces better solutions, especially on the largest instances where the number of vehicles used is significantly reduced. © 2009 Wiley Periodicals, Inc. NETWORKS, 2009
Edge assembly‐based memetic algorithm for the capacitated vehicle routing problem
Authors: Nagata Yuichi , Bräysy Olli
Published: August 2009

Vehicle routing problems are at the heart of most decision support systems for real‐life distribution problems. In vehicle routing problem a set of routes must be determined at lowest total cost for a number of resources (i.e., fleet of vehicles) located at one or several points (e.g., depots, warehouses) to efficiently service a number of demand or supply points. In this article a new memetic algorithm is suggested for the standard capacitated vehicle routing problem. The proposed algorithm combines the edge assembly (EAX) crossover with well‐known local searches and allows for infeasible solutions with respect to capacity and route duration constraints after invoking the crossover. To address the constraint violation, an efficient modification algorithm is also suggested. Experimental tests on 47 standard benchmarks demonstrate that the suggested method is robust and competitive, finding new best‐known solution to 20 well‐studied instances and repeating the existing best‐known solution for 24 problems in a reasonable computing time. © 2009 Wiley Periodicals, Inc. NETWORKS, 2009
Computational methods for delay parabolic and time‐fractional partial differential equations
Authors: Rihan Fathalla A.
Published: August 2009

This article is concerned with ϑ‐methods for delay parabolic partial differential equations. The methodology is extended to time‐fractional‐order parabolic partial differential equations in the sense of Caputo. The fully implicit scheme preserves delay‐independent asymptotic stability and the solution continuously depends on the time‐fractional order. Several numerical examples of interest are included to demonstrate the effectiveness of the method. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
Pointwise supercloseness of pentahedral finite elements
Authors: Liu Jinghong , Zhu Qiding
Published: August 2009

This article derives the weak estimate of the first type for pentahedral finite elements over uniform partitions of the domain for the Poisson equation. The estimate for the W1,1‐seminorm of the discrete derivative Green's function is also given. Using these two estimates, we obtain the pointwise supercloseness of derivatives of the pentahedral finite element approximation and the interpolant to the true solution. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
Comparison between variational iteration method and homotopy perturbation method for linear and nonlinear partial differential equations with the nonhomogeneous initial conditions
Authors: Ateş İnan , Yıldırım Ahmet
Published: August 2009

In this study, linear and nonlinear partial differential equations with the nonhomogeneous initial conditions are considered. We used Variational iteration method (VIM) and Homotopy perturbation method (HPM) for solving these equations. Both methods are used to obtain analytic solutions for different types of differential equations. Four examples are presented to show the application of the present techniques. In these schemes, the solution takes the form of a convergent series with easily computable components. The present methods perform extremely well in terms of efficiency and simplicity. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
Approximating solutions to the Dirichlet problem in Rn using one analytic function
Authors: Whitley R.J. , Hromadka T.V. , Horton S.B.
Published: August 2009

A simpler proof is given of the result of (Whitley and Hromadka II, Numer Methods Partial Differential Eq 21 (2005) 905–917) that, under very mild conditions, any solution to a Dirichlet problem with given continuous boundary data can be approximated by a sum involving a single function of one complex variable; any analytic function not a polynomial can be used. This can be applied to give a method for the numerical solution of potential problems in dimension three or higher. © 2009 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 2010
A qualitative investigation into the donor lapsing experience
Authors: Nathan Amber , Hallam Leslie
Published: August 2009

Donor attrition is costing charities a fortune. Previous research has examined the relative importance of the antecedents to donor loyalty versus lapsing. This study qualitatively builds on this. It reports the results of workshops and interviews that took lapsers and donors back through their donor and lapser journeys. It drills down into and unpacks their experiences—inclusive of the (previously undocumented) lapsing experience itself. It reveals striking similarities between the cancellation of a direct debit and other more conventional purchase decisions. Most worryingly, it seems that most people stop supporting a given charity because they had never really had any loyalty to it in the first place. Charities are not meeting people's needs as donors. There is a distinct lack of understanding between charities and their donors, and donors are lapsing because charities give them little reason to stay. The authors conclude with practical recommendations for the management of attrition.

Copyright © 2009 John Wiley & Sons, Ltd.
Methoxy poly (ethylene glycol) thiosulfonate: new activated polymer derivatives for thiol‐specific modification
Authors: Zhao Yong‐Jiang , Zhai Yan‐qin , Su Zhi‐Guo , Ma Guang‐Hui
Published: August 2009

Thiol‐reactive methoxy poly (ethylene glycol) (mPEG) derivatives, mPEG methanethiosulfonate (mPEG‐MTS) and mPEG phenylthiosulfonate (mPEG‐PTS), were synthesized by one‐step S‐alkylation of mPEG‐halide with the corresponding sodium thiosulfonate. These functionalized polymers were fully characterized by 1H NMR, 13C NMR, GPC as well as MALDI‐TOF. To demonstrate the potential application of mPEG‐MTS and mPEG‐PTS, papain and recombinant human granulocyte colony‐stimulating factor (rhG‐CSF) were used as prototype protein for thiol‐selective PEGylation. The PEGylated products were verified by one or more of the following methods: SDS‐PAGE, HPLC, HPSEC as well as MALDI‐TOF. Compared with native rhG‐CSF, the PEGylated rhG‐CSF was further characterized by in vitro cell proliferative assay and preserved 59% biological activity. Furthermore, mPEG20k‐MTS was used to modify BSA nanoparticles coated with thiol groups. FT‐IR and ζ‐potential assay demonstrated that mPEG thiosulfonate can be effectively immobilized at the nanoparticles' surface via disulfide linkage to form hydrophilic and neutral corona. Therefore, we have demonstrated thiol‐selective PEG derivatives, endowed with unusual versatility, for practical use and potential exploitation. Copyright © 2009 John Wiley & Sons, Ltd.
Müller cell‐derived VEGF is a significant contributor to retinal neovascularization
Authors: Bai Yanyan , Ma Jian‐xing , Guo Junjing , Wang Juanjuan , Zhu Meili , Chen Ying , Le Yun‐Zheng
Published: August 2009

Vascular endothelial growth factor (VEGF‐A) is a major pathogenic factor and a therapeutic target for age‐related macular degeneration, diabetic retinopathy, and retinopathy of prematurity. Despite intensive effort in the field, the cellular mechanisms of VEGF action remain virtually uninvestigated. This situation makes it difficult to design cellular target‐based therapeutics for these diseases. In light of the recent finding that VEGF is a potential neurotrophic factor, revealing the cellular mechanisms of VEGF action becomes necessary to preserve its beneficial effect and inhibit its pathological function in long‐term anti‐VEGF therapeutics for ocular vascular diseases. We therefore generated conditional VEGF knockout mice with an inducible Cre/lox system and determined the significance of Müller cell‐derived VEGF in retinal development and maintenance and ischaemia‐induced neovascularizartion and vascular leakage. Retinal development in the conditional VEGF knockout mice was analysed by examining retinal and choroidal vasculatures and retinal morphology and function. Ischaemia‐induced retinal neovascularization and vascular leakage in the conditional VEGF knockout mice were analysed with fluorescein angiography, quantification of proliferative neovascular cells, immunohistochemistry, and immunoblotting using an oxygen‐induced retinopathy model. Our results demonstrated that disruption of Müller cell‐derived VEGF resulted in no apparent defects in retinal and choroidal vasculatures and retinal morphology and function, significant inhibition of the ischaemia‐induced retinal neovascularization and vascular leakage, and attenuation of the ischaemia‐induced breakdown of the blood‐retina barrier. These results suggest that the retinal Müller cell‐derived VEGF is a major contributor to ischaemia‐induced retinal vascular leakage and pre‐retinal and intra‐retinal neovascularization. The observation that a significant, but not complete, reduction of VEGF in the retina does not cause detectable retinal degeneration suggests that appropriate doses of anti‐VEGF agents may be important to the safe treatment of retinal vascular diseases. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
The p53‐mediated sensitivity of cancer cells to chemotherapeutic agents is conditioned by the status of the retinoblastoma protein
Authors: Derenzini Massimo , Brighenti Elisa , Donati Giulio , Vici Manuela , Ceccarelli Claudio , Santini Donatella , Taffurelli Mario , Montanaro Lorenzo , Treré Davide
Published: August 2009

Despite the well‐established function of p53 in determining cell cycle arrest and/or apoptosis in response to cytostatic/cytotoxic stresses, the role of the p53 status in the response to chemotherapeutic agents in human cancers has been not clearly defined. We wondered whether this was due to the fact that the p53‐mediated response to chemotherapy drugs might be conditioned by the status of the retinoblastoma protein (pRb), a downstream factor of the pathway activated by p53 stabilization, which is frequently disrupted in cancer. The dependence of p53‐mediated chemosensitivity on pRb status was first investigated in a prospective study on the prognostic relevance of p53 in breast cancer patients treated with adjuvant chemotherapy (5‐fluorouracil, methotrexate and cyclophosphamide). Univariate analysis of disease‐free survival (DFS) indicated that the p53 status, immunohistochemically evaluated, had no predictive value if considered independently of the pRb status. However, in patients with cancer with pRb neither lost nor hyperphosphorylated, p53 was significantly associated with the prognosis and, in a multivariate analysis of DFS including the established clinical and histopathological prognostic parameters, was found to be the only factor predicting the progression of the disease. We then studied the role of pRb status in the p53‐mediated response to 5‐fluorouracil and methotrexate or doxorubicin treatment in three human cancer cell lines. We found that in these cells the chemosensitivity was strictly dependent on the p53 status. However, either RB1 silencing or pRb hyperphosphorylation, caused by p16(INK4a) silencing, strongly reduced the p53‐mediated response to chemotherapeutic agents. These results demonstrated that: (a) the p53‐mediated response to chemotherapeutic agents induces a cytostatic/cytotoxic effect only in cancers with unaltered pRb pathway; and (b) the p53 status can actually predict the clinical outcome in this group of cancer patients. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Cholinergic switch associated with morphological differentiation in neuroblastoma
Authors: Bourdeaut Franck , Janoueix‐Lerosey Isabelle , Lucchesi Carlo , Paris Régine , Ribeiro Agnès , de Pontual Loïc , Amiel Jeanne , Lyonnet Stanislas , Pierron Gaëlle , Michon Jean , Peuchmaur Michel , Delattre Olivier
Published: August 2009

The morphology of malignant cells distinguishes between undifferentiated, poorly differentiated and differentiating neuroblastomas and constitutes a strong prognostic factor. Spontaneous or treatment‐induced maturation characterizes a subset of neuroblastomas. It constitutes the basis of retinoic acid treatment to improve survival in aggressive neuroblastomas. However, the molecular events that drive differentiation are poorly understood. In the present study we have investigated the relationships between gene expression profiles and differentiation criteria in stroma‐poor neuroblastomas. This study included three undifferentiated (UN), 20 poorly differentiated (PDN) and 11 differentiating (DN) neuroblastomas. These groups could be clearly separated using unsupervised clustering methods, which further enabled a major classification impact of genes involved in neural development, differentiation and function to be identified. UNs are characterized by highASCL1, highPHOX2B, lowGATA2, lowTHand lowDBHexpressions. Most PDNs harbour a clear adrenergic phenotype, even in the presence of missensePHOX2Bmutations. Finally, all DN tumours demonstrate cholinergic features. Depending upon their association with adrenergic characteristics, this enables dual ‘cholinergic/adrenergic’ and ‘fully cholinergic’ neuroblastomas to be defined. This suggests that the cholinergic switch, a final specification process that occurs physiologically in a minority of sympathetic neurons, is a critical step of differentiation in some neuroblastic tumours. This switch is associated with a down regulation ofDBHthat is apparently not strictly dependent uponPHOX2B. Conversely,GATA2andTFAP2Bmay play critical roles in maintaining adrenergic features in poorly differentiated tumours. Copyright © 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.
Veno‐occlusive disease as a complication of preoperative chemotherapy for Wilms tumor: A clinico‐pathological analysis
Authors: Jagt Charissa T. , Zuckermann Michelle , Ten Kate Fibo , Taminiau Jan A.J.M. , Dijkgraaf Marcel G.W. , Heij Hugo , De Kraker Jan , Verschuur Arnauld C.
Published: August 2009

Background

Vincristine (VCR) and actinomycin D (ACD) form the backbone of chemotherapeutic regimens of Wilms tumor treatment. Veno‐occlusive disease (VOD) is a potentially life‐threatening complication of ACD.

Objectives

To investigate the incidence of VOD after preoperative chemotherapy and assess the effect of dose and frequency of administrating ACD on the occurrence of VOD.

Methods

A single‐center retrospective study of patients where liver biopsies were performed after 4 or 8 weeks of preoperative chemotherapy. Patients had localized or metastatic Wilms tumor and were treated according to SIOP 9, 93‐1, or 2001 protocol. A correlation was analyzed between histologically confirmed VOD, laboratory parameters, and mode and frequency of ACD administration. Long‐term hepatic toxicity was assessed 5 years after the end of therapy.

Results

Ninety‐one patients were included in this analysis. Forty‐one patients (45.1%) had histological evidence of VOD. The incidence of histologically proven VOD was significantly correlated with single administration of 45 µg/kg ACD (SIOP 2001 protocol) as compared to repeated dosing of l5 µg/kg (P = 0.003). Fifty‐two percent of all patients had mild‐to‐severe abnormal liver enzymes 5 years after accomplishing therapy.

Conclusion

Despite short‐course preoperative chemotherapy regimen, patients are at risk of developing histological VOD. This risk is higher when ACD is administered in a 1‐day 45 µg/kg regimen as compared to 3 days l5 µg/kg. Pediatr Blood Cancer 2009; 53:1211–1215. © 2009 Wiley‐Liss, Inc.
mRNA expression profile of multidrug resistance genes in childhood acute lymphoblastic leukemia. Low expression levels associated with a higher risk of toxic death
Authors: Cortez Maria A.A. , Scrideli Carlos A. , Yunes José A. , Valera Elvis T. , Toledo Sílvia R.C. , Pavoni‐Ferreira Patrícia C.B. , Lee Maria L.M. , Petrilli Antônio S. , Brandalise Silvia R. , Tone Luiz G.
Published: August 2009

Background

Increased activity of multidrug resistance (MDR) genes has been associated with treatment failure in acute leukemias, although with controversial reports. The objective of the present study was to assess the expression profile of the genes related to MDR: ABCB1, ABCC1, ABCC3, ABCG2, and LRP/MVP in terms of the clinical and biological variable and the survival of children with acute lymphoblastic leukemia (ALL).

Procedure

The levels of mRNA expression of the drug resistance genes ABCB1, ABCC1, ABCC3, ABCG2, and LRP/MVP were analyzed by quantitative real‐time PCR using the median values as cut‐off points, in consecutive samples from 140 children with ALL at diagnosis.

Results

Expression levels of the ABCG2 gene in the patient group as a whole (P = 0.05) and of the ABCG2 and ABCC1 genes in patients classified as being at high risk were associated with higher rates of 5‐year event‐free survival (EFS) (P = 0.04 and P = 0.01). Expression levels of the ABCG2 gene below the median were associated with a greater chance of death related to treatment toxicity for the patient group as a whole (P = 0.009) and expression levels below the median of the ABCG2 and ABCC1 genes were associated with a greater chance of death due to treatment toxicity for the high‐risk group (P = 0.02 and P = 0.03, respectively).

Conclusion

The present data suggest a low participation of the drug efflux genes in treatment failure in patients with childhood ALL. However, the low expression of some of these genes may be associated with a higher death risk related to treatment toxicity. Pediatr Blood Cancer 2009;53:996–1004. © 2009 Wiley‐Liss, Inc.
Improvement of neurological status and quality of life in children with opsoclonus myoclonus syndrome at long‐term follow‐up
Authors: Catsman‐Berrevoets Coriene E. , Aarsen Femke K. , van Hemsbergen Marloes L.C. , van Noesel Max M. , Hakvoort‐Cammel Frederique G.A.J. , van den Heuvel‐Eibrink Marry M.
Published: August 2009

Background

Kinsbourne syndrome or opsoclonus myoclonus syndrome (OMS) is characterized by rapid, involuntary, irregular conjugate eye movements (opsoclonus), myoclonic jerking of the limbs and trunk, ataxia, and behavioral disturbances. In general, the outcome of neurologic and behavioral symptoms is poor. Studies on quality of life (Qol) and recovery after very long‐term follow‐up of children with OMS are lacking.

Methods

We studied long‐term cancer survival, neurologic recovery, and Qol of a consecutive series of eight patients with OMS that were treated in our center. Two cross‐sectional follow‐up evaluations were conducted at a 3‐year interval (T1 and T2).

Results

In four out of eight children with OMS a neuroblastoma (NBL) was diagnosed and surgically removed completely. All children received immuno‐modulatory therapy, consisting of prednisone (three children), prednisone and ACTH (four children), or prednisone, ACTH, and gammaglobulin (one child). At T1, median follow‐up time was 9.5 years (range 3–14 years) after OMS onset and at T2, 11.6 years (range 6–17 years). Neurologic functioning improved in all children, reflected by a significant improvement of the mean Z‐score in the motor domain of the Qol questionnaire at T2 as compared to T1. In contrast, seven children continued to have a severe developmental delay at T2. No significant difference in any of the variables was found between NBL survivors and OMS patients without NBL.

Conclusion

Cognitive and behavioral impairments and not a motor impairment, such as ataxia, appear to be predominant at long‐term in children with OMS. Pediatr Blood Cancer 2009;53:1048–1053. © 2009 Wiley‐Liss, Inc.
Alexander disease: An important mimicker of focal brainstem glioma
Authors: Van Poppel Katherine , Broniscer Alberto , Patay Zoltan , Morris E. Brannon
Published: August 2009

We report the case of a 6‐year‐old male who was referred to a tertiary oncology center with a focal brainstem lesion which was presumed to be neoplastic. Due to the symmetric nature of the lesion on magnetic resonance imaging, the evaluation was expanded to investigate other possible causes and eventual diagnosis of Alexander's disease (AD) was made. AD is a neurodegenerative disease which must be included in the differential for tumor‐like lesions within the posterior fossa. Pediatr Blood Cancer 2009; 53:1355–1356. © 2009 Wiley‐Liss, Inc.
Structural, electrical and percolation threshold of Al/polymethylmethacrylate nanocomposites
Authors: Álvarez M.P. , Poblete V.H. , Rojas P.A.
Published: August 2009

Aluminum‐embedded polymethylmethacrylate (PMMA) composites were produced by using different aluminum concentrations in the polymer matrix. The aluminum particles were spherical with a particle size of 80 nm. The hot compression molding method in inert atmosphere for all the composites was used in their preparation. The PMMA matrix was analyzed using solution viscosimetry analysis and it did not evidence degradation of the PMMA matrix. The microstructure of the composites was examined with scanning electron microscopy (SEM). The electrical conductivity was measured as a function of the aluminum content and the composite fabricated with 10 vol.% aluminum presented a conductivity three order of magnitude higher than that of pure PMMA. The enhancement in conductivity can be explained by means of segregated percolation path theory and the experimental results are in agreement with the theoretical law. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers
Validity of computerized diagnoses, procedures, and drugs for inflammatory bowel disease in a northern California managed care organization
Authors: Liu Liyan , Allison James E. , Herrinton Lisa J.
Published: August 2009

Purpose

Resources for studying inflammatory bowel disease (IBD) are needed in evaluations of drug safety including traditional drugs and new biologics agents. We developed an IBD registry, with ascertainment from computerized visit information.

Objective

We sought to characterize the positive predictive value (PPV) of IBD case‐finding using computerized data compared with chart review.

Methods

We identified 2906 persons aged 89 years or younger with one or more IBD diagnoses in computerized visit data during the period of 1996–2002. The diagnosis of IBD was confirmed through chart review. Adopting chart review as the gold standard, the validity of computerized encounter data to determine IBD was estimated.

Results

Among the 2906 study subjects with one or more ICD‐9 diagnosis codes of 555 or 556 in computerized data, 81% were confirmed as having IBD by chart review. Defining cases as those who underwent two or more visits without regard to diagnostic procedures or drug utilization maximized the correct classification of cases (PPV, 95%).

Conclusions

The quality of IBD diagnoses in computerized data is adequate to meet the aims of a wide range of research studies. Copyright © 2009 John Wiley & Sons, Ltd.
The psychological impact of a specialist referral and telephone intervention on male cancer patients: a randomised controlled trial
Authors: Livingston Patricia M. , White Victoria M. , Hayman Jane , Maunsell Elizabeth , Dunn Stewart M. , Hill David
Published: August 2009

Objective: To examine the psychological impact of a referral and telephone intervention, involving information and support, among men with colorectal cancer (CRC) and prostate cancer.

Methods: 571 newly diagnosed male CRC (N=182) and prostate (N=389) cancer patients were block‐randomised into three arms. In the two intervention arms, the specialist actively referred men to a Cancer Helpline. In Active Referral—4 outcalls, men received calls from the Helpline within 1 week of diagnosis, and at 6 weeks, 3 months and 6 months post‐diagnosis. In Active Referral—1 outcall, men received one call within 1 week of diagnosis. In the control arm, Passive Referral, patients were referred to the Helpline, with contact at their initiative. Participants completed scales measuring cancer‐specific distress, anxiety and depression at study entry, then 4, 7 and 12 months post‐diagnosis. Random effects regression models compared rates of change in these outcomes between study arms.

Results: At the first outcall, over 85% of participants in both intervention arms discussed treatment management and psychological/emotional issues. Among the Active Referral—4 outcalls arm, over 80% of participants discussed psychological/emotional issues at each call. Mean changes over time in cancer‐specific distress, anxiety and depression were similar between study arms.

Conclusion: Although men were willing to discuss psychosocial issues via the telephone, we found no psychological impact. Further research is required to determine whether the intervention is more effective for patients who do not have psychosocial support or have unmet information needs. Copyright © 2009 John Wiley & Sons, Ltd.
Regional ventilation distribution in non‐sedated spontaneously breathing newborns and adults is not different
Authors: Schibler Andreas , Yuill Margaret , Parsley Chloe , Pham Trang , Gilshenan Kristen , Dakin Carolyn
Published: August 2009

Background:

In adults, ventilation is preferentially distributed towards the dependent lung. A reversal of the adult pattern has been observed in infants using radionuclide ventilation scanning. But these results have been obtained in infants and children with lung disease. In this study we investigate whether healthy infants have a similar reverse pattern of ventilation distribution.

Study Design:

Measurement of regional ventilation distribution in healthy newborn infants during non‐REM sleep in comparison to adults.

Methods:

Twenty‐four healthy newborns and 13 adults were investigated with electrical impedance tomography (EIT) in supine and prone position. Regional ventilation distribution was assessed with profiles of relative impedance change. The phase lag between dependent and non‐dependent ventilation was calculated as a measure of asynchronous ventilation.

Results:

In newborns and adults the geometric center of ventilation was centrally located in the lung at 52.2 ± 6.2% from anterior to posterior and at 50.5 ± 14.7%, respectively. Using impedance profiles, ventilation was equally distributed to the dependent and non‐dependent lung regions in newborns. Ventilation distribution in adults was similar. Phase lag characteristics of the impedance signal showed that infants had slower emptying of the dependent lung than adults.

Conclusion:

The speculated reverse pattern of regional ventilation distribution in healthy infants compared to adults could not be demonstrated. Gravity had little effect on ventilation distribution in both infants and adults measured in supine and prone position. Pediatr Pulmonol. 2009; 44:851–858. © 2009 Wiley‐Liss, Inc.
A case of localized adrenergic urticaria mimicking an allergic reaction to a sweat chloride test
Authors: Klebanova Y. , LeGrys V. , Cooper D. , Levy D. , Santora D. , Schwindt C.
Published: August 2009

Adrenergic urticaria (AU) is a rare type of physical urticaria triggered by stress. It is frequently confused with IgE‐mediated urticaria or other physical urticarias. This report describes a case of localized adrenergic urticaria triggered by a sweat chloride test in an adolescent male with multiple atopic disorders. A pruritic papular rash at the site of a sweat chloride test prompted an evaluation for allergic and physical urticarias using multiple skin test methods. A positive intradermal skin test to noradrenaline, which reproduced the rash observed during the sweat test, lead to the diagnosis of adrenergic urticaria. This is the first case report describing an immediate adrenergic urticarial reaction to sweat chloride testing in a patient with other atopic disorders. Pediatr Pulmonol. 2009; 44:935–938. © 2009 Wiley‐Liss, Inc.
Thermoelectric properties of rapid hot pressed polycrystalline Ag1−xPb18SbTe20synthesized from doping PbTe nanocrystals
Authors: Xin Xingliang , Jiang Yang , Kong Daxing , Zhong Honghai , Chen Lei , Yu Dabin
Published: August 2009

Polycrystalline thermoelectric (TE) materials of n‐type and with compositions of Ag1−xPb18SbTe20(x = 0, 0.1, 0.2) were prepared by rapid hot pressing from alloy powders, which were obtained by ball milling crystalline ingots. The ingots were synthesized from PbTe nanoparticles, made by solvothermal reactions, and Ag, Sb and Te powders via vacuum‐sealed melting in quartz ampoules. Through rapid hot pressing at 748 K for 15 min under 80 MPa, the polycrystalline samples possessed 95% relative densities with the average grain size of 5 µm. The electrical resistivity, Seebeck coefficient and thermal conductivity of the Ag1−xPb18SbTe20(x = 0, 0.1, 0.2) samples were measured in the range from room temperature (RT) to 673 K. The thermal conductivity was dramatically decreased, caused by scattering of phonons from grain boundaries and interfaces. By optimizing the values of carrier concentration and carrier transference, the Ag1−xPb18SbTe20(x = 0.2) sample achieved a maximumZTvalue of 1.019 at 673 K.
Influence of admixtures on the properties of biferroic Pb(Fe0.5Nb0.5)O3 ceramic
Authors: Bochenek Dariusz , Surowiak Zygmunt
Published: August 2009

The ferroelectromagnetic Pb(Fe0.5Nb0.5)O3 (PFN) ceramic was synthesized by a powder calcining method. The aim of this work was to decrease the electric conduction of the biferroic PFN ceramic as a result of admixing it with metal oxides or carbonates. Investigation results concerning the influence of admixtures of manganese, chromium and lanthanum oxides and potassium and strontium carbonates on direct current electric conduction and dielectric parameters of the PFN ceramic are presented. Crystallographic and morphological studies were carried out using X‐ray diffraction and scanning microscopy techniques. The specimens obtained were subjected to dielectric, electric direct current conductivity, hysteresis loop and electromechanical tests. By adding small amounts of admixtures it was possible to decrease (admixtures of manganese or chromium) or increase (admixtures of lanthanum, strontium or potassium) the area of the phase transition of the PFN ceramic. It was found that admixtures of manganese and potassium decreased the electric conduction of the PFN ceramic. PFN admixed with elements of small ions, manganese and chromium, is characterized by a better set of dielectric parameters and lower dielectric losses compared to the PFN ceramic without admixtures.
Device characteristics and metal–dielectric high reflectivity coating analysis of λ ∼ 1.3 µm InGaAsP/InGaAsP MQW PBH lasers
Authors: Leem J. W. , Yu J. S.
Published: August 2009

The cavity length‐dependent characteristics of compressively strained InGaAsP/InGaAsP multiple quantum well planar buried heterostructure lasers operating at λ ∼ 1.3 µm were investigated under continuous‐wave mode. The uncoated 600 µm long laser exhibits Pmax = 33.6 mW and Ith = 12.9 mA at 25 °C with dλ/dT = 0.35 nm/K and dλ/dPe = 0.044 nm/mW, leading to stable beam characteristics of 19.7° (parallel) × 24.1° (perpendicular). From the inverse slope efficiency versus cavity length plot, the loss parameters of internal differential efficiency (ηi) and internal optical loss (αi) were extracted, i.e., ηi = 78% and αi = 10.6 cm−1. The transparent current density of Jtr = 0.12 kA/cm2 and modal gain of G = 49.5 cm−1 were also estimated from cavity length‐dependent threshold current density measurements. Metal–dielectric Au/Ti/SiO2 layers for high reflectivity (HR) coating were analyzed using theoretical calculations and experimental results. For the HR‐coated 600 µm long laser with Au (150 nm)/Ti (5 nm)/SiO2 (250 nm), Pmax increased up to 61 mW at 25 °C with a reduced Ith of 10.6 mA compared to the uncoated laser, providing an HR of about 94%.
Amorphous films of tris(8‐hydroxyquinolinato)aluminium: Force‐field, morphology, and charge transport
Authors: Lukyanov Alexander , Lennartz Christian , Andrienko Denis
Published: August 2009

The effect of the force‐field parameters on the morphology and charge dynamics is assessed for amorphous films of tris(8‐hydroxyquinolinato)aluminium. Two force‐fields are used for non‐bonded parameters, OPLS and Williams 99, whereas bonded interactions are obtained from first‐principles calculations. By comparing densities and glass transition temperatures we conclude that the OPLS‐based force field provides a better description of the amorphous morphology. At the same time, the difference in molecular packing does not significantly affect the distribution of charge hopping rates or charge carrier mobility.
Conductive diamond tips with sub‐nanometer electrical resolution for characterization of nanoelectronics device structures
Authors: Hantschel T. , Demeulemeester C. , Eyben P. , Schulz V. , Richard O. , Bender H. , Vandervorst W.
Published: August 2009

Over the past decade, boron‐doped diamond tips have become the ultimate choice for electrically characterizing microelectronics devices using scanning probe methods such as scanning spreading resistance microscopy (SSRM). Although nanometer‐scale electrical resolution has been demonstrated, the development of a reliable probe process remained a challenge. Therefore, we did develop in this work solid diamond tips with sub‐nanometer electrical resolution and integrated them into metal cantilevers using a peel‐off approach. It is shown that the ultra‐high tip resolution is achieved by diamond nanocrystals protruding from the apex of the diamond pyramid. The yield for sub‐nanometer probes is 20–30% in air and 40–60% in vacuum. This paper describes the fabrication scheme, discusses probe characterization, and shows SSRM measurements obtained with these probes. Our probes are routinely used for SSRM measurements and current efforts are focusing on increasing the yield for sub‐nanometer tips further.
Aharonov–Bohm interference in single‐walled carbon nanotube electron resonators
Authors: Zhang Yong , Han Mei , Zheng Hongbo
Published: August 2009

Using the π orbital tight‐binding model and the multi‐channel Laudauer–Büttiker formula, both the effects of the Aharonov–Bohm effect and the curvature on quantum conductance oscillations of the electron resonators composed of armchair and primary zigzag single‐walled carbon nanotubes (SWNTs) in an axial magnetic field have been studied. It is found that the rapid and slow conductance oscillation periods of the armchair SWNTs depend on both the magnetic field and gate voltage in addition to the sample length. More interestingly, for the case of the primary zigzag SWNTs, one or two conductance oscillations in two different ranges of gate voltages was found for the first time, which would not exist without the curvature effect and should be observed in future experiments.
The polaron properties in GaAs and CdSe quantum‐well wires under an applied electric field
Authors: Vartanian Arshak L.
Published: August 2009

The effect of an electric field on the polaron properties in GaAs and CdSe quantum‐well wires embedded in a polar matrix are studied theoretically. By using the Lee, Low, and Pines (LLP) variational method, the analytical expressions for the quasi‐one‐dimensional Fröhlich polaron self‐energy (PSA), effective mass (PEM), and mean number of virtual phonons are obtained as functions of the wire sizes and the strength of the electric field applied along the growth direction.
Clustering of functional molecules on a single‐walled carbon‐nanotube surface and its effect on hydrogen storage
Authors: Iyakutti K. , Surya V. J. , Rajarajeswari M. , Venkataramanan N. S. , Kawazoe Y.
Published: August 2009

This first‐principles study deals with the effect of clustering of different functional molecules adsorbed on the surface of the single‐walled carbon nanotubes (SWCNTs) (5, 5). Here we report the results of our investigation on the effect of clustering on storage capacity, the nature of H2 bonding and strength of H2 binding. The investigation is carried out for (5, 5) SWCNT functionalized with different types of hydrogen‐rich molecules such as AlH3, NH3, BH3 and NiH2. In the case of AlH3, the clustering turns into dimerization with the adsorption of H2. This is distinctly different from the other three cases. Weak clustering is observed for full coverage of NH3 molecules. The clustering starts with higher coverage of H2 molecules in the case of SWCNT functionalized with BH3 molecules. The clusters of NiH2 molecules, chemisorbed on the surface of carbon nanotube, are observed. Our study indicates that depending upon the materials used for the functionalization, the clustering pattern is different and the effect on the above‐mentioned factors is also different.
On the properties of auxetic rotating stretching squares
Authors: Attard Daphne , Manicaro Elaine , Gatt Ruben , Grima Joseph N.
Published: August 2009

Auxeticity (i.e. negative Poisson's ratios) is associated with particular geometrical features and deformation mechanisms occurring within a system. Among the models which have been shown to exhibit such behaviour are the ‘rotating rigid unit’ models, in particular two‐dimensional systems constructed from connected squares. In this work, we consider such a system which deforms through simultaneous stretching and rotation of the squares. We derive the analytical model describing its mechanical behaviour to show that the mechanical properties depend on the relative magnitude of the stretching and hinging constants, the square dimensions and the angle between the squares. In particular we show that the mechanical properties of the combined model are dependent on the relative contribution of the individual mechanisms and that by changing the relative magnitude of the force constants and/or the geometric parameters describing the system, the contribution from each of the two mechanisms, and thus the Poisson's ratio, can be set to predesired values.
Associations between the plant communities of floodplain wetlands, water regime and wetland type
Authors: Barrett Rose , Nielsen Daryl L. , Croome Roger
Published: August 2009

Understanding how floodplain wetland vegetation is influenced by water regimes can inform the management of regulated river systems by targeting appropriate environmental water allocations. In this study, we examined plant community structure in 21 floodplain wetlands adjacent to the Murray River between Hume Reservoir and Tocumwal, south‐eastern Australia. Correlations between the water regime of the previous 25 years, and wetland type were investigated. We found the structure of plant communities, as assessed by the richness and percentage cover of plants, to be related to water regime, with clear differences between the communities of wetlands with historical ‘Wet’, ‘Dry’ and ‘Intermediate’ water regimes. Plant community structure was also related to wetland type, with differences being found between the communities of floodplain depressions, flood‐runners and cut‐off meanders. Managers of riverine/floodplain ecosystems need to consider both wetland type and water regime when planning strategies for the restoration or conservation of floodplain wetland vegetation in regulated river systems. Copyright © 2009 John Wiley & Sons, Ltd.
Practical application of the vanishing tetrad test for causal indicator measurement models: An example from Health Related Quality of Life
Authors: Bollen Kenneth A. , Lennox Richard D. , Dahly Darren L.
Published: August 2009

The authors acknowledge Eli Lilly and Company for providing funding and data for this project and Mark E. Boye, PhD, for review of the manuscript.
Revisited: The future of general systems research: Update on obstacles, potentials, case studies
Authors: Troncale Len
Published: August 2009

This paper updates observations made 25 years ago on more than 33 impediments, possibilities, and developments relative to the development of systems awareness. It briefly describes three new ‘generations’ of systems awareness that were only partly anticipated at that time, but spontaneously appeared since the original article. These three new ‘movements’ include “complex systems” research and tools from the hard sciences, systems science approaches in the descriptive sciences of geology and biology, and the computer simulation or systems engineering approaches of the new ‘system of systems’ (SOS) movement. Some trends in developments in systems education are cited. The article emphasizes the continuing need for stronger coupling of systems theories and systems applications as well as faster transfer from science to application. It ends with one sentence updates on each of the original 33 needs including information on how 4 have been substantially answered while 14 have shown only very limited progress, and 15 no progress at all. The paper also cites appearance of a significant new obstacle, namely incompatibility of systems modeling tools for hybrid system of systems problems. Overall, the conclusion is that this field devoted to synthesis and integration is actually becoming more fragmented and unintegrated while the information and tools for its eventual synthesis multiply in a healthy manner. Copyright © 2009 John Wiley & Sons, Ltd.