bluuebunny/crossref_metadata_2025 huggingface dataset:
Band‐notched small square slot antenna for ultra‐wideband applications
Authors: Ojaroudi M. , Ojaroudi N.
Published: March 2012

In this article, a novel printed slot antenna for ultra wideband applications with variable frequency band‐notch characteristic is presented.The proposed antenna consists of a modified radiating stub with a pair of L‐shaped slits and a ground plane with two T‐shaped parasitic structures, which provides a wide usable fractional bandwidth of more than 135% (2.81–5.1 GHz) while showing the band rejection performance in the frequency band of 5 to 6 GHz. By cutting a pair of L‐shaped slits with variable dimensions on the radiating stub frequency band‐stop performance is generated and we can control its characteristics such as band‐notch frequency and its bandwidth. The designed antenna has a small size of 20 × 20 mm2. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behavior within the UWB frequency range. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1138–1143, 2012
Frequency reconfigurable zeroth‐order resonant antenna using RF MEMS switch
Authors: Jang Youngsoo , Choi Jaehyurk , Lim Sungjoon
Published: March 2012

In this article, a frequency reconfigurable zeroth‐order resonant (ZOR) antenna using RF micro‐electron‐mechanical‐system (MEMS) switch has been implemented. The ZOR characteristics of the proposed antenna are realized using the composite right‐ and left‐handed (CRLH) transmission line, which is realized by way of a rectangular slot on the ground plane of mushroom‐structured antenna to minimize the antenna size. In addition, the RF MEMS switches are introduced on the slotted ground plane to change operation frequency. Depending on the states of the RF MEMS switch on the slotted ground plane, a shunt inductance of the CRLH transmission line is changed, and its resonant frequency becomes tunable. From the experimental results, the resonant frequency of the proposed antenna is changed from 4.95 to 4.66 GHz. Additionally, the proposed antenna's size is reduced by 71.5% compared with the conventional half‐wavelength patch antenna. © 2012 Wiley Periodicals, Inc. Microwave Opt Technol Lett 54:1266–1269, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.26803
Using anchoring vignettes to assess the comparability of self‐rated feelings of sadness, lowness or depression in France and Vietnam
Authors: Guindon G. Emmanuel , Boyle Michael H.
Published: March 2012

General measures of self‐rated health are collected routinely in national health surveys and widely used in the analyses of determinants of health and health care utilization. However, these subjective assessments can be influenced by health expectations (contextualized beliefs about health) that may vary systematically across individuals and be associated with their socio‐demographic characteristics. Our objective is to contrast the impact of health expectations associated with respondent characteristics (reporting heterogeneity) on self‐rated feelings of sadness, lowness or depression obtained from general population samples in France and Vietnam. Based on self ratings and ratings in response to common anchoring vignettes depicting different levels of depression, we used nationally representative data from the World Health Survey conducted in France (2002) and Vietnam (2002–2003) and a modification of the standard probit model to test and adjust for reporting heterogeneity associated with individual characteristics. We find evidence of reporting heterogeneity within France and Vietnam and across the two countries. In particular we find that, when adjusted for reporting heterogeneity, sex is no longer significantly associated with self‐rated feelings of sadness, lowness or depression in France. Given the absence of clear biological markers in the definitions of depressive disorders and the substantial impact reporting heterogeneity is shown to have, measures of depressive disorders based on self‐reports should be interpreted with caution. Copyright © 2012 John Wiley & Sons, Ltd.
Benchmark calculations of 29Si–1H spin–spin coupling constants across double bond
Authors: Rusakov Yury Yu. , Krivdin Leonid B. , Nosova Valentina M. , Kisin Alexander V.
Published: March 2012

Benchmark calculations of geminal and vicinal 29Si–1H spin–spin coupling constants across double bond in three reference alkenylsilanes have been carried out at both DFT and SOPPA levels in comparison with experiment. At the former, four density functionals, B3LYP, B3PW91, PBE0 and KT3, were tested in combination with five representative basis sets. At the latter, three main SOPPA‐based methods, SOPPA, SOPPA(CC2) and SOPPA(CCSD), were examined in combination with the same series of basis sets. On the whole, the wavefunction methods showed much better results as compared to DFT, with the most efficient combination of SOPPA/cc‐pVTZ‐su2 characterized by a mean absolute error of only 0.4 Hz calculated for a set of nine coupling constants in three compounds with a sample span of around 40 Hz. Copyright © 2012 John Wiley & Sons, Ltd.
The Integrated Deconvolution Estimation Model: Effect of Inter‐Laboratory 13C NMR Analysis on IDEM Performance
Authors: Al‐Saleh Mohammad A. , Soares João B. P. , Duever Thomas A.
Published: March 2012

The IDEM estimates the reactivity ratios of multiple‐site‐type catalysts used to make ethylene/α‐olefin copolymers. Analytical data from high‐temperature GPC and 13C NMR are required in the estimation process. The CSLD information from the 13C NMR is a crucial step in the estimation method due to NMR sensitivity and probe efficiency. The effect of inter‐laboratory analysis on IDEM parameter estimation and model predictions is studied. The copolymer samples are analyzed at the University of Waterloo and Dow Chemical Research Center at Freeport, Texas without standardization. The results prove that the IDEM is a robust parameter estimation model for ethylene/α‐olefin copolymers made with multiple‐site‐type catalysts, even when the copolymer samples are analyzed in different laboratories.

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Chronic pelvic pain syndrome/bladder pain syndrome: Taking stock, looking ahead: ICI‐RS 2011
Authors: Hanno Philip , Andersson Karl Eric , Birder Lori , Elneil Suzy , Kanai Anthony , Pontari Michel
Published: March 2012

This review reflects the presentations and subsequent discussions at the International consultation on Incontinence Research Society's annual meeting. It updates the current definitions and diagnostic and treatment algorithms for bladder pain syndrome and chronic pelvic pain syndrome (non‐bacterial prostatitis), highlights some specific basic research findings from discussion participants, looks at what we can hope to eventually learn from a large multicenter National Institutes of Health study, reviews future research pathways as articulated by the National Urologic Research Agenda of the American Urological Association and others, discusses recent therapeutic efforts, and concludes with discussion points from the ICI‐RS meeting. Neurourol. Urodynam. 31:375–383, 2012. © 2012 Wiley Periodicals, Inc.
Nocturia think tank: Focus on nocturnal polyuria: ICI‐RS 2011
Authors: Weiss Jeffrey P. , Ruud Bosch J.L.H. , Drake Marcus , Dmochowski Roger R. , Hashim Hashim , Hijaz Adonis , Johnson Theodore M. , Vinter Juul Kristian , Nørgaard Jens Peter , Norton Peggy , Robinson Dudley , Tikkinen Kari A.O. , Van Kerrebroeck Philip E.V. , Wein Alan J.
Published: March 2012

The following is a report of the proceedings of the Nocturia Think Tank sessions of the annual International Consultation on Incontinence‐Research Society, which took place June 13–15, 2011 in Bristol, UK. The report is organized into sections pertaining to the main topics of discussions having occurred at that meeting, centering on the relationship of nocturnal polyuria (NP) and nocturia but also synthesizing more current evidence advancing our knowledge of the diagnosis and management of nocturia. This article is not meant to be a comprehensive review on the subject of nocturia, a number of which are available in the recent literature. All authors were physically present during, or in a preliminary session just prior to, the meeting in Bristol. Neurourol. Urodynam. 31:330–339, 2012. © 2012 Wiley Periodicals, Inc.
Unintended? The effects of adoption of the Sarbanes‐Oxley Act on nonprofit organizations
Authors: Nezhina Tamara G. , Brudney Jeffrey L.
Published: March 2012

This article investigates the benefits and costs to nonprofit organizations emanating from the adoption of the Sarbanes‐Oxley Act (2002). The act was intended to stem financial malfeasance in the for‐profit sector; nevertheless the article finds that about half the surveyed nonprofits adopted provisions of the act and experienced effects in proportion to the level of adoption. About one in four of the nonprofits attributed benefits of better financial controls and reduced risk of accounting fraud to the adoption of the Sarbanes‐Oxley Act. More than one‐third of the nonprofit organizations reported increased fees for external audit, and about 15 percent cited “reallocation of resources from program to administrative expenses.” This article discusses the unintended positive and negative effects of public policy on nonprofit organizations.
Synthesis of well‐defined amphiphilic polymethylene‐b‐poly(ε‐caprolactone)‐b‐poly(acrylic acid) triblock copolymer via a combination of polyhomologation, ring‐opening polymerization, and atom transfer radical polymerization
Authors: Yuan Cong , Lu Hui‐Chao , Li Qi‐Zheng , Yang Sen , Zhao Qiao‐Ling , Huang Jin , Wei Liu‐He , Ma Zhi
Published: March 2012

Well‐defined amphiphilic polymethylene‐b‐poly(ε‐caprolactone)‐b‐poly(acrylic acid) (PM‐b‐PCL‐b‐PAA) triblock copolymers were synthesized via a combination of polyhomologation, ring‐opening polymerization (ROP), and atom transfer radical polymerization (ATRP). First, hydroxyl‐terminated polymethylenes (PM‐OH; Mn = 1100 g mol−1; Mw/Mn = 1.09) were produced by polyhomologation followed by oxidation. Then, the PM‐b‐PCL (Mn = 10,000 g mol−1; Mw/Mn = 1.27) diblock copolymers were synthesized via ROP of ε‐caprolactone using PM‐OH as macroinitiator and stannous octanoate (Sn(Oct)2) as a catalyst. Subsequently, the macroinitiator transformed from PM‐b‐PCL in high conversion initiated ATRPs of tert‐butyl acrylate (tBA) to construct PM‐b‐PCL‐b‐PtBA triblock copolymers (Mn = 11,000–14,000 g mol−1; Mw/Mn = 1.24–1.26). Finally, the PM‐b‐PCL‐b‐PAA triblock copolymers were obtained via the hydrolysis of the PtBA segment in PM‐b‐PCL‐b‐PtBA triblock copolymers. The chain structures of all the polymers were characterized by gel permeation chromatography, proton nuclear magnetic resonance, and Fourier transform infrared spectroscopy. Porous films of such triblock copolymers were fabricated by static breath‐figure method and observed by scanning electron microscope. The aggregates of PM‐b‐PCL‐b‐PAA triblock copolymer were studied by transmission electron microscope. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Insights into the Atmospheric Pressure Plasma‐Enhanced Chemical Vapor Deposition of Thin Films from Methyldisiloxane Precursors
Authors: Fanelli Fiorenza , Lovascio Sara , d'Agostino Riccardo , Fracassi Francesco
Published: March 2012

This work describes the plasma‐enhanced chemical vapor deposition of thin films at atmospheric pressure using dielectric barrier discharges fed with argon, oxygen and different methyldisiloxanes, i.e., hexamethyldisiloxane, pentamethyldisiloxane, and 1,1,3,3‐tetramethyldisiloxane. The influence of the methyldisiloxane chemical structure and of the oxygen/methyldisiloxane feed ratio is investigated in order to provide insights into the organosilicon plasma chemistry at atmospheric pressure. As expected the FT‐IR and XPS analyses show that the carbon content of the coatings depends on the number of methyl groups in the precursor molecule; in the case of coatings obtained with PMDSO and TMDSO carbon removal seems to be further enhanced by the presence of SiH bonds. Gaschromatography‐mass spectrometry analyses of the exhaust gas allow to assess the precursor depletion and to perform the quali‐quantitative determination of by‐products (e.g., silanes, siloxanes, silanols) formed by plasma activation. The results are exploited to rise hypotheses on the contribution of the different reaction pathways on the deposition mechanism.

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Superior herniation of the mediastinum presenting as an anterior neck mass on straining
Authors: McDougall Catherine M. , Culham Gordon , Seear Michael D. , Chilvers Mark A.
Published: March 2012

We report an infant with an anterior neck mass present only on straining. Airway fluoroscopy revealed this to be due to superior mediastinal herniation. Neck masses apparent only during Valsalva maneuver are rare and awareness of the differential diagnosis is important to avoid unnecessary investigation or surgery. Pediatr Pulmonol. 2012; 47:710–712. © 2012 Wiley Periodicals, Inc.
The identification and internal validation of a preoperative serum biomarker panel to determine extracapsular extension in patients with prostate cancer
Authors: Oon Sheng F. , Fanning Deirdre M. , Fan Yue , Boyce Susie , Murphy T. Brendan , Fitzpatrick John M. , Watson R. William
Published: March 2012

BACKGROUND

Accurate preoperative staging of prostate cancer (PCa) is important but current diagnostic methods cannot accurately determine extracapsular extension (ECE), resulting in the possible triage of patients towards a less appropriate arm of therapy. This has consequences to patient care and better methods of preoperatively determining ECE are required.

METHODS

We followed a biomarker development pathway and compared the preoperative serum expressions of VEGF‐D, PEDF, IGF‐I, IGFBP3, and CD14 in patients from the Irish Prostate Cancer Research Consortium (PCRC) with radical prostatectomy determined ECE against patients with nonECE.

RESULTS

The expression measurements of five proteins were fitted into a logistic regression model and backwards variable elimination methods were applied which resulted in a model with IGFBP3 and CD14 as the best combination biomarker panel. This panel was tested in an independent cohort of patients using an optimized multiplex electrochemiluminescence assay. Receiver operating characteristic curves were generated and the areas under the curve (AUC) were calculated as an estimation of prediction accuracy. The biomarker panel was validated with an AUC of 76.6%, and a sensitivity and specificity of 80% and 75% was obtained.

CONCLUSIONS

This is the first internally validated, preoperative serum biomarker panel that identifies ECE in patients with Gleason score 7 PCa with AUC 76.6%. The panel surpasses the routinely used diagnostic standards in accuracy and may help to improve preoperative cancer staging, better inform treatment options, and improve the referral patterns of patients with urgently treatable cancers towards more appropriate arms of therapy. Prostate 72:1523–1531, 2012. © 2012 Wiley Periodicals, Inc.
Epigenetic down regulation of RASSF10 and its possible clinical implication in prostate carcinoma
Authors: Dansranjavin Temuujin , Wagenlehner Florian , Gattenloehner Stefan , Steger Klaus , Weidner Wolfgang , Dammann Reinhard , Schagdarsurengin Undraga
Published: March 2012

BACKGROUND

Ras association domain family (RASSF) comprises several tumor suppressor genes, which are often epigenetically inactivated in human tumors. Here, we aim to analyze the relevance of the recently identified member RASSF10 in prostate carcinogenesis.

METHODS

RASSF10 promoter methylation and mRNA expression were investigated by bisulfite‐pyrosequencing and qRT‐PCR, respectively, in prostate carcinoma (PCa) cell lines (LNCaP, 22Rv1, DU‐145) and in 83 primary PCa and 53 primary benign prostatic hyperplasia (BPH) tissues obtained after radical prostatectomy. Histological localization of RASSF10 was done by in situ hybridization. To prove the epigenetic nature of RASSF10 down regulation, PCa cell lines were treated with 5‐aza‐2‐deoxycytidine and trichostatin A. Potential function of RASSF10 was analyzed in LNCaP by colony formation and apoptosis assays.

RESULTS

RASSF10 mRNA was localized to cells of the basal layer of the prostatic gland. Absence (LNCaP) and decrease (22Rv1, DU‐145) of RASSF10 expression was associated with promoter methylation and could be restored by demethylating agents. A link between RASSF10 mRNA reduction and promoter methylation was also detected in primary prostate tissues (P = 0.006), where PCa showed more frequently reduced RASSF10 levels when compared with BPH (33.7% vs. 13.2%, P = 0.009). RASSF10 methylation could be further associated with advanced tumor stage and advanced age (P‐values < 0.05). Our preliminary functional assays revealed the ability of RASSF10 to inhibit colony formation (P = 0.018) and to increase apoptosis (P = 0.035).

CONCLUSIONS

This is the first study, which demonstrates the frequent epigenetic inactivation of RASSF10 in PCa and its implication in clinical symptoms of PCa. Prostate 72:1550–1558, 2012. © 2012 Wiley Periodicals, Inc.
Mimicking the action of folding chaperones by Hamiltonian replica‐exchange molecular dynamics simulations: Application in the refinement of de novo models
Authors: Fan Hao , Periole Xavier , Mark Alan E.
Published: March 2012

The efficiency of using a variant of Hamiltonian replica‐exchange molecular dynamics (Chaperone H‐replica‐exchange molecular dynamics [CH‐REMD]) for the refinement of protein structural models generated de novo is investigated. In CH‐REMD, the interaction between the protein and its environment, specifically, the electrostatic interaction between the protein and the solvating water, is varied leading to cycles of partial unfolding and refolding mimicking some aspects of folding chaperones. In 10 of the 15 cases examined, the CH‐REMD approach sampled structures in which the root‐mean‐square deviation (RMSD) of secondary structure elements (SSE‐RMSD) with respect to the experimental structure was more than 1.0 Å lower than the initial de novo model. In 14 of the 15 cases, the improvement was more than 0.5 Å. The ability of three different statistical potentials to identify near‐native conformations was also examined. Little correlation between the SSE‐RMSD of the sampled structures with respect to the experimental structure and any of the scoring functions tested was found. The most effective scoring function tested was the DFIRE potential. Using the DFIRE potential, the SSE‐RMSD of the best scoring structures was on average 0.3 Å lower than the initial model. Overall the work demonstrates that targeted enhanced‐sampling techniques such as CH‐REMD can lead to the systematic refinement of protein structural models generated de novo but that improved potentials for the identification of near‐native structures are still needed. Proteins 2012; © 2012 Wiley Periodicals, Inc.
Growth and characterization of self‐assembled low‐indium composition InGaN nanodots by alternate admittance of precursors
Authors: Zhao Wei , Wang Lai , Wang Jiaxing , Lv Wenbin , Hao Zhibiao , Luo Yi
Published: March 2012

Low‐indium composition InGaN nanodots are grown on GaN/Al2O3 by alternate admittance of triethylgallium (TEGa), trimethylindium (TMIn), and ammonia (NH3) using metalorganic vapor phase epitaxy. Since the lattice mismatch between metal (Ga, In) and GaN is large during the admittance of group III precursors and the alternate admittance of precursors can enhance the surface diffusion of adatoms, it is believed that the growth mode of InGaN nanodots is the Volmer–Weber mode. The admittance time is optimized and injecting TMIn with NH3 can increase indium composition. The ultraviolet photoluminescence spectra exhibit small temperature‐dependent redshift and a sensitive intensity change dependent on indium composition.
Synthesis of a new donor, MOET‐TTP, and the crystal structure, electrical, and magnetic properties of (MOET‐TTP)2MCl4 (M = Fe and Ga)
Authors: Shirahata Takashi , Ito Tetsuya , Toki Shinya , Misaki Yohji
Published: March 2012

A new 2,5‐bis(1,3‐dithiol‐2‐ylidene)‐1,3,4,6‐tetrathiapentalene (BDT‐TTP) type donor, 2‐(4,5‐dimethoxy‐1,3‐dithiol‐2‐ylidene)‐5‐(4,5‐ethylenedithio‐1,3‐dithiol‐2‐ylidene)‐1,3,4,6‐tetrathiapentalene (MOET‐TTP) was synthesized and its magnetic and non‐magnetic anion salts (MOET‐TTP)2MCl4 (M = Fe and Ga), were prepared. These salts are isostructural and belong to the space group of P1. They show metal‐like behavior down to 200 K for the FeCl4 salt and 20 K for the GaCl4 salt. The band structures of these salts are two‐dimensional. The MCl4 anions are located between the donor columns and close to the ethylenedithio and methoxy groups of the donor molecules. The magnetic susceptibilities of the FeCl4 salts follow the Curie–Weiss law with Curie constant of 4.3 emu K mol−1 and Weiss temperature of θ = −1.8 K, revealing a weak antiferromagnetic interaction of 3d spins of the FeCl4 anions. The ${\rm Fe}\cdots {\rm Fe}$ (6.508(3) Å) and ${\rm Cl}\cdots {\rm Cl}$ (3.78–4.69 Å) distances in the crystal structure of the salt are significantly long. Therefore, the direct magnetic interaction between the 3d spins of the nearest neighboring Fe3+ ions does not seem readily accessible.
Properties of crystalline coronene: Dispersion forces leading to a larger van der Waals radius for carbon
Authors: Fedorov Igor , Zhuravlev Yurii , Berveno Victor
Published: March 2012

We investigated the electronic structure of crystalline coronene within the framework of the dispersion corrected density‐functional theory (DFT‐D). We use the DFT‐D2 and DFT‐D3 methods. Utilization of the DFT‐D3 leads to a correct account of the dispersion forces, which results in a good agreement of the computed lattice parameters and cohesive energy. In the framework of DFT‐D3 the cohesive energy of crystalline coronene is 1.483 eV. Computed lattice constants and cohesive energy show good agreement with experimental data if larger van der Waals (vdW) radius for carbon is used. Based on the relaxed crystal structures, we have computed the band structure, total and deformation electron density.
Properties of nitride‐based photovoltaic cells under concentrated light illumination
Authors: Yamamoto Shota , Mori Mikiko , Kuwahara Yosuke , Fujii Takahiro , Nakao Tatsuo , Kondo Shinichiro , Iwaya Motoaki , Takeuchi Tetsuya , Kamiyama Satoshi , Akasaki Isamu , Amano Hiroshi
Published: March 2012

We investigated the properties of nitride‐based solar cells under concentrated light illumination from 1 to 200 suns. The conversion efficiency of our solar cells increased with increasing concentration up to 200 suns. The short‐circuit cur‐ rent density, open‐circuit voltage, fill factor, and conversion efficiency were 510 mA/cm2, 1.9 V, 70%, and 3.4%, respectively, under an air mass filter of 1.5G at 200 suns and room temperature. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Escalation strategies for combination therapy Phase I trials
Authors: Sweeting Michael J. , Mander Adrian P.
Published: March 2012

Phase I clinical trials aim to identify a maximum tolerated dose (MTD), the highest possible dose that does not cause an unacceptable amount of toxicity in the patients. In trials of combination therapies, however, many different dose combinations may have a similar probability of causing a dose‐limiting toxicity, and hence, a number of MTDs may exist. Furthermore, escalation strategies in combination trials are more complex, with possible escalation/de‐escalation of either or both drugs. This paper investigates the properties of two existing proposed Bayesian adaptive models for combination therapy dose‐escalation when a number of different escalation strategies are applied. We assess operating characteristics through a series of simulation studies and show that strategies that only allow ‘non‐diagonal’ moves in the escalation process (that is, both drugs cannot increase simultaneously) are inefficient and identify fewer MTDs for Phase II comparisons. Such strategies tend to escalate a single agent first while keeping the other agent fixed, which can be a severe restriction when exploring dose surfaces using a limited sample size. Meanwhile, escalation designs based on Bayesian D‐optimality allow more varied experimentation around the dose space and, consequently, are better at identifying more MTDs. We argue that for Phase I combination trials it is sensible to take forward a number of identified MTDs for Phase II experimentation so that their efficacy can be directly compared. Researchers, therefore, need to carefully consider the escalation strategy and model that best allows the identification of these MTDs. Copyright © 2012 John Wiley & Sons, Ltd.
Rank‐based estimate of four‐parameter logistic model
Authors: Crimin Kimberly S. , McKean Joseph W. , Vidmar Thomas J.
Published: March 2012

During drug development, the calculation of inhibitory concentration that results in a response of 50% (IC50) is performed thousands of times every day. The nonlinear model most often used to perform this calculation is a four‐parameter logistic, suitably parameterized to estimate the IC50 directly. When performing these calculations in a high‐throughput mode, each and every curve cannot be studied in detail, and outliers in the responses are a common problem. A robust estimation procedure to perform this calculation is desirable. In this paper, a rank‐based estimate of the four‐parameter logistic model that is analogous to least squares is proposed. The rank‐based estimate is based on the Wilcoxon norm. The robust procedure is illustrated with several examples from the pharmaceutical industry. When no outliers are present in the data, the robust estimate of IC50 is comparable with the least squares estimate, and when outliers are present in the data, the robust estimate is more accurate. A robust goodness‐of‐fit test is also proposed. To investigate the impact of outliers on the traditional and robust estimates, a small simulation study was conducted. Copyright © 2012 John Wiley & Sons, Ltd.
From deflection function to potential energy: A Firsov approach critical analysis
Authors: Alves Márcio Oliveira , Oliveira Jessé Moreira , Lemes Nelson Henrique Teixeira , Braga João Pedro
Published: March 2012

The Firsov inverse method was used to retrieve potential energy for helium–helium system from deflection function. Using a combination of accurate simulated data for large deflection function and a Lennard–Jones type potential for smaller values, it was possible to recover the short‐range potential in excellent agreement with the theoretical results. Errors in the deflection function ranged from 1 to 10% with a collision energy from 2 × 10−3 to 2 eV. Inverted potential were obtained with a precision from 2 to 8%. This study explores the possibility to use Firsov approach for small collision energy, unlike the previous work on the subject. The method was proved to be robust, stable against experimental error, and very easy to be implemented numerically. © 2012 Wiley Periodicals, Inc.
Atoms‐in‐molecules analysis of the effect of intermolecular interactions on dielectric properties in hydrogen‐bonded material 5‐bromo‐9‐hydroxyphenalenone
Authors: Otaki Hiroki , Ando Koji
Published: March 2012

Intermolecular interactions in molecular crystal of 5‐bromo‐9‐hydroxyphenalenone are analyzed by means of Bader's theory of atoms in molecules. A set of criteria to ascertain the presence of a hydrogen bond is applied to two candidates of intermolecular contacts suggested by our previous work [Otaki and Ando,Phys. Chem. Chem. Phys.2011,13, 10719]. It is shown that they almost satisfy the criteria to confirm the existence of intermolecular CH···O hydrogen bond. In addition to the hydrogen bonding, other types of interactions, such as H···H and H···Br, are found in one of the candidates. The discussions are extended to explain how the molecular dipole moment is induced by surrounding molecules. It is also found that the bias in the atomic charges due to the electrophilicity of the oxygen atom is strongly correlated with the induced dipole moment. © 2012 Wiley Periodicals, Inc.
Likelihood‐based methods for regression analysis with binary exposure status assessed by pooling
Authors: Lyles Robert H. , Tang Li , Lin Ji , Zhang Zhiwei , Mukherjee Bhramar
Published: March 2012

The need for resource‐intensive laboratory assays to assess exposures in many epidemiologic studies provides ample motivation to consider study designs that incorporate pooled samples. In this paper, we consider the case in which specimens are combined for the purpose of determining the presence or absence of a pool‐wise exposure, in lieu of assessing the actual binary exposure status for each member of the pool. We presume a primary logistic regression model for an observed binary outcome, together with a secondary regression model for exposure. We facilitate maximum likelihood analysis by complete enumeration of the possible implications of a positive pool, and we discuss the applicability of this approach under both cross‐sectional and case‐control sampling. We also provide a maximum likelihood approach for longitudinal or repeated measures studies where the binary outcome and exposure are assessed on multiple occasions and within‐subject pooling is conducted for exposure assessment. Simulation studies illustrate the performance of the proposed approaches along with their computational feasibility using widely available software. We apply the methods to investigate gene–disease association in a population‐based case‐control study of colorectal cancer. Copyright © 2012 John Wiley & Sons, Ltd.
Efficient use of longitudinal CD4 counts and viral load measures in survival analysis
Authors: Holte S. E. , Randolph T. W. , Ding J. , Tien J. , McClelland R. S. , Baeten J. M. , Overbaugh J.
Published: March 2012

CD4 counts and viral loads are dynamic quantities that change with time in HIV‐infected persons. Commonly used single summary measures, such as viral load set point or early CD4 count, do not explicitly account for changes in viral load or CD4 counts or other features of the overall time course of these measures. However, the efficient use of all repeated measurements within each subject is often a challenge made more difficult by sparse and irregular sampling over time. Here, we illustrate how functional principal component (FPC) analysis provides an effective statistical approach for exploiting the patterns in CD4 count and viral load data over time. We demonstrate the method by using data from Kenyan women who acquired HIV‐1 during follow‐up in a cohort that practices high‐risk activities and were subsequently followed up prospectively from early infection. The FPC scores for each woman obtained using this method served as informative summary statistics for the CD4 count and viral load trajectories. Similar to baseline CD4 count or viral set point, the first FPC score can be interpreted as a single‐value summary measure of an individual's overall CD4 count or viral load. However, unlike most single‐value summaries of CD4 count or viral load trajectories, the first FPC score summarizes the dynamics of these quantities and is seen to reveal specific features of the trajectories associated with mortality in this cohort. Moreover, the FPC scores are shown to be a more powerful prognostic factor than other common summaries when used in survival analysis. Copyright © 2012 John Wiley & Sons, Ltd.
Using factor mixture analysis to model heterogeneity, cognitive structure, and determinants of dementia: an application to the Aging, Demographics, and Memory Study
Authors: Viroli C.
Published: March 2012

The Aging, Demographics, and Memory Study is the first extensive study of cognitive impairment and dementia of population in the USA. A large sample of participants with ages 71 years or older has answered an in‐depth questionnaire which included an extensive cognitive assessment. One of the principal aims of the study was to assign a diagnosis of dementia, cognitive impairment but not demented, or normal to the respondents. Because of this heterogeneity, we apply factor mixture model to the set of neuropsychological measures of the study in order to perform clustering of subjects and dimension reduction simultaneously. Moreover, we consider an extended variant of the model by incorporating a set of demographics and clinical covariates which directly affect the latent variables of the factor mixture model. The interest of the analysis is to investigate whether respondents exhibit the same association of overall cognitive functioning with the covariates or whether groups of respondents exist that exhibit different association with the covariates, indicating different determinants of overall cognitive functioning. Copyright © 2012 John Wiley & Sons, Ltd.
Misuse of DeLong test to compare AUCs for nested models
Authors: Demler Olga V. , Pencina Michael J. , D'Agostino Ralph B.
Published: March 2012

The area under the receiver operating characteristics curve (AUC of ROC) is a widely used measure of discrimination in risk prediction models. Routinely, the Mann–Whitney statistics is used as an estimator of AUC, while the change in AUC is tested by the DeLong test. However, very often, in settings where the model is developed and tested on the same dataset, the added predictor is statistically significantly associated with the outcome but fails to produce a significant improvement in the AUC. No conclusive resolution exists to explain this finding. In this paper, we will show that the reason lies in the inappropriate application of the DeLong test in the setting of nested models. Using numerical simulations and a theoretical argument based on generalized U‐statistics, we show that if the added predictor is not statistically significantly associated with the outcome, the null distribution is non‐normal, contrary to the assumption of DeLong test. Our simulations of different scenarios show that the loss of power because of such a misuse of the DeLong test leads to a conservative test for small and moderate effect sizes. This problem does not exist in cases of predictors that are associated with the outcome and for non‐nested models. We suggest that for nested models, only the test of association be performed for the new predictors, and if the result is significant, change in AUC be estimated with an appropriate confidence interval, which can be based on the DeLong approach. Copyright © 2012 John Wiley & Sons, Ltd.
Pooled‐testing procedures for screening high volume clinical specimens in heterogeneous populations
Authors: Bilder Christopher R. , Tebbs Joshua M.
Published: March 2012

Pooled testing is a procedure commonly used to reduce the cost of screening a large number of individuals for infectious diseases. In its simplest form, pooled testing works by compositing a set of individual specimens (e.g., blood or urine) into a common pool. If the pool tests negative, all individuals within it are diagnosed as negative. If the pool tests positive, retesting is needed to decode the positive individuals from the negative individuals. Traditionally, pooled testing has assumed that each individual has the same probability of being positive. However, this assumption is often unrealistic, especially when known risk factors can be used to measure distinct probabilities of positivity for each individual. In this paper, we investigate new pooled‐testing algorithms that exploit the heterogeneity among individual probabilities and subsequently reduce the total number of tests needed, while maintaining accuracy levels similar to standard algorithms that do not account for heterogeneity. We apply these algorithms to data from the Infertility Prevention Project, a nationally implemented program supported by the Centers for Disease Control and Prevention. Copyright © 2012 John Wiley & Sons, Ltd.
On the 40th anniversary of the journal X‐Ray Spectrometry
Authors: Revenko A. G.
Published: March 2012

This journal, X‐Ray Spectrometry, celebrates its 40th anniversary this year. The state of the publications on X‐ray spectral analysis from 1972 onward is considered. The distribution of materials over countries is presented, as published in X‐Ray Spectrometry for 40 years, in 5‐year time intervals: 1972–1976, 1977–1981, and so on. The participation of Russian scientists contributing to the publications in this journal is discussed. Copyright © 2012 John Wiley & Sons, Ltd.
Identification of Risk Factors for Esophagojejunal Anastomotic Leakage after Gastric Surgery
Authors: Deguchi Yasunori , Fukagawa Takeo , Morita Shinji , Ohashi Masaki , Saka Makoto , Katai Hitoshi
Published: March 2012

Background

Despite the development of the surgical technique and improvements in perioperative management, anastomotic leakage still occurs at esophagojejunal anastomoses after total or proximal gastrectomy. Anastomotic leakage is one of the major complications of concern, chiefly because it can lead to death. The objective of the present study was to identify the risk factors for esophagojejunal anastomotic leakage.

Methods

The study was based on retrospective analysis of the data of a total of 1,640 consecutive patients who underwent total, proximal, or completion gastrectomy, including esophagojejunal anastomosis, between 1999 and 2008.

Results

Thirty‐five patients (2.1 %) developed anastomotic leakage. Univariate analysis revealed patient age, pulmonary insufficiency, lymph node dissection, combined resection of other organs, omental resection, operative time, blood loss, intraoperative blood transfusion, and postoperative creatinine level were the significant factors influencing anastomotic leakage. Multivariate analysis identified pulmonary insufficiency and the duration of the operation as the predictors of anastomotic leakage.

Conclusions

To avoid leakage, surgeons should take care in creating the anastomosis in gastrectomy patients, particularly in cases of poor pulmonary function or when the procedure requires a longer operation.
Oral Supplementation with Dihomo‐γ‐Linolenic Acid (DGLA)‐Enriched Oil Increases Serum DGLA Content in Healthy Adults
Authors: Tanaka Takao , Kakutani Saki , Horikawa Chika , Kawashima Hiroshi , Kiso Yoshinobu
Published: March 2012

Dihomo‐γ‐linolenic acid (DGLA) is one of the polyunsaturated fatty acids, and is expected to show anti‐allergic activity. We examined the effects of supplementation with DGLA‐enriched oil (450 mg as free DGLA) for 4 weeks in healthy adults in a randomized controlled study. The DGLA composition in the total fatty acids of serum phospholipids increased from 2.0 to 3.4 %, and returned to the initial level after a 4‐week washout. No side effects or changes in blood biochemical parameters were observed. These results indicate that serum DGLA content can be safely increased by supplementation with 450 mg DGLA under these conditions.
Kinetic Study of Hydroperoxide Degradation in Edible Oils Using Electron Spin Resonance Spectroscopy
Authors: Roman Olesea , Courtois Francis , Maillard Marie‐Noëlle , Riquet Anne‐Marie
Published: March 2012

Lipid oxidation is a complex phenomenon involving free radicals which are highly reactive molecular species. The life‐time of these radical species is extremely short and their detection is therefore difficult. Several electron spin resonance (ESR) spectroscopy methodologies make it possible to identify, quantify and measure the reactivity of radical species formed during oxidation–reduction reactions. In this study we took advantage of the specificity of ESR spectroscopy to detect radical compounds in order to determine the rate constants of hydroperoxide degradation, a key reaction involved in lipid oxidation. The interaction of 5‐doxyl stearic acid and lipid‐derived radicals was studied by following the intensity of ESR spectra. A kinetic model was developed to simulate data analysis obtained by ESR and values of rate constants for hydroperoxide degradation were determined at 100 and 110 °C. This quantitative approach of ESR spectroscopy has produced useful information about new rate estimates for hydroperoxide degradation in edible oils.
Explaining educational differences in adolescent substance use and early sexual debut: The role of parents and peers
Authors: de Looze Margaretha , Harakeh Zeena , van Dorsselaer Saskia A.F.M. , Raaijmakers Quinten A.W. , Vollebergh Wilma A.M. , ter Bogt Tom F.M.
Published: March 2012

Previous studies from a wide variety of European countries have demonstrated that low educated adolescents engage more frequently in health risk behaviors compared to high educated adolescents. The present study investigates the mediating roles of parental knowledge and time spent with peers in this relationship. Data were retrieved from a nationally representative sample of 12‐ to 16‐year old Dutch adolescents (N = 5422). Risk behaviors were measured by adolescents’ report of daily smoking, binge drinking and cannabis use in the previous month, and sexual debut before age 17. Low educated adolescents indicated that their parents had less knowledge on their whereabouts and reported spending more time with peers than high educated adolescents. Both factors mediated the relationship with health risk behaviors. These results hint to parenting practices and adolescent peer relations as points of reference for prevention and intervention work aiming to reduce educational inequalities in adolescent health risk behaviors.
Esre: A novel essential non‐coding RNA in Escherichia coli
Authors: Chen Zhichao , Wang Yi , Li Yarong , Li Yue , Fu Nan , Ye Jiang , Zhang Huizhan
Published: March 2012

YigP gene (GeneID: 948915) locates between ubiquinone biosynthetic genes ubiE and ubiB in Escherichia coli. GeneBank annotates yigP as a putative protein‐coding gene. In this study, we found a new essential sRNA gene, esre, locates within the region of yigP. The E. coli strain with inactive esre must rely on a complementary plasmid to survive. Moreover, RACE experiments showed esre encodes an RNA molecule of 252 nt. Further experiments revealed esre gene is immune to frame shift mutations and the function of esre depends mostly on the RNA secondary structure, which are typical traits of sRNA. Since it is difficult to predict the target of an essential sRNA, more research is needed to reveal the function and mechanism of esre.
Current and emerging concepts on the role of peripheral signals in the control of food intake and development of obesity
Authors: Duca F. A. , Covasa M.
Published: March 2012

The gastrointestinal peptides are classically known as short-term signals, primarily inducing satiation and/or satiety. However, accumulating evidence has broadened this view, and their role in long-term energy homeostasis and the development of obesity has been increasingly recognised. In the present review, the recent research involving the role of satiation signals, especially ghrelin, cholecystokinin, glucagon-like peptide 1 and peptide YY, in the development and treatment of obesity will be discussed. Their activity, interactions and release profile vary constantly with changes in dietary and energy influences, intestinal luminal environment, body weight and metabolic status. Manipulation of gut peptides and nutrient sensors in the oral and postoral compartments through diet and/or changes in gut microflora or using multi-hormone ‘cocktail’ therapy are among promising approaches aimed at reducing excess food consumption and body-weight gain.
Cold-water corals landed by bottom longline fisheries in the Azores (north-eastern Atlantic)
Authors: Sampaio Í. , Braga-Henriques A. , Pham C. , Ocaña O. , de Matos V. , Morato T. , Porteiro F.M.
Published: March 2012

The impact of bottom trawling on cold-water corals (CWC) has been thoroughly studied and shown to be long-lasting; however the effects of bottom longlining on CWC ecosystems have received little attention. The present paper identifies the principal CWC species landed by bottom longlining in Faial (Azores) from 150 to 600 m depth. Data were obtained from a survey of 297 landings during four months coupled with 16 interviews with fishermen. A distinction was made among corals brought on deck directly entangled in the fishing gear (primary by-catch) from corals brought up associated with other larger CWC species or rocks (secondary by-catch). Forty-five (15.2%) of 297 fishing trips surveyed landed coral specimens. The survey recorded 39 different CWC taxa in the by-catch, belonging to five different orders (Scleractinia, Alcyonacea, Antipatharia, Zoanthidea and Anthoathecata). Secondary by-catch included a larger number of species but the total number of corals was in the same order of magnitude for both groups. The taxa most frequently encountered wereLeiopathesspp., Errina dabneyiand Dendrophyllia sp. CWC taxa in the by-catch were mostly medium size (10–60 cm), 3-dimensional and branched colonies. Local ecological knowledge of fishermen confirmed that the corals recorded were representative of their past experience and also revealed a general agreement that there has been a decrease of CWC by-catch on traditional fishing grounds. Corals are common by-catch in bottom longline fisheries around the Azores and so conservation measures may be required.
Effects of CH foam preplasma on fast ignition
Authors: Hata M. , Sakagami H. , Sunahara A. , Johzaki T. , Nagatomo H.
Published: March 2012

Creation of a preformed plasma (preplasma) by heating laser prepulse is crucial to fast ignition. Because it is difficult to control the prepulse and preplasma, control of fast electron beam generation by low-density foam was recently reported. However, this simulation study ignored the foam preplasma. Therefore, we calculated foam preplasma formation using a hydrodynamic code and investigated the effects of the preplasma on fast ignition by using integrated simulations, including radiation hydrodynamic, Particle-In-Cell (PIC) and Fokker–Planck simulations. We conclude that the average core temperature decreased by approximately 10% in the integrated simulations of the foam preplasma case.
Effects of dielectric discontinuity on the dispersion characteristics of the tape helix slow-wave structure with two metal shields
Authors: Zhang Yu , Liu Jinliang , Wang Shiwen , Fan Xuliang , Zhang Hongbo , Feng Jiahuai
Published: March 2012

In the tape helix slow-wave system, discontinuous dielectrics have great effects on the dispersion characteristics. In this paper, the tape helix slow-wave system, including an inner and an outer metal shield, tape helix, nylon support, and de-ionized water as filling dielectric, was analyzed. Effects of dielectric discontinuity caused by the support dielectric and filling dielectric on the dispersion characteristics were studied in detail. The dispersion relations, phase velocities, slow-wave coefficients, and electric lengths of the spatial harmonics in the system were calculated. Results showed that, if the permittivity of support dielectric was smaller than that of the filling dielectric, frequencies of the spatial harmonics in the system rose, phase velocities and slow-wave coefficients increased, the slow-wave effect of the system was weakened so that the previous electric length was shortened. The reverse condition corresponded to the reverse results, and the electromagnetic simulation also proved it. By use of the helical pulse forming line of accelerator based on the studied tape helix slow-wave system, the electric lengths of the system were tested as 188.5 ns and 200 ns in experiments where the thicknesses of nylon support were 6 mm and 3 mm, respectively. The theoretical calculation results 198 ns and 211 ns basically corresponded to experimental results, which only had relative errors as 5 and 5.5%, respectively.