bluuebunny/crossref_metadata_2025 huggingface dataset:
High temporal and spatial resolution imaging of peripheral vascular malformations
Authors: Mostardi Petrice M. , Young Phillip M. , McKusick Michael A. , Riederer Stephen J.
Published: June 2012

Purpose:

To assess the performance of a recently developed 3D time‐resolved CE‐MRA technique, Cartesian Acquisition with Projection‐Reconstruction‐like sampling (CAPR), for accurate characterization and treatment planning of vascular malformations of the periphery.

Materials and Methods:

Twelve patient studies were performed (eight female, four male; average age, 33 years). The protocol consisted of three‐dimensional (3D) time‐resolved CE‐MRA followed by a single late phase T1‐weighted acquisition. Vascular malformations were imaged in the forearm, hand, thigh, and foot. Imaging evaluation was performed for accurate characterization of lesion type, identification of feeding and draining vessels, involvement with surrounding tissue, overall quality for diagnosis and treatment planning, and correlation with conventional angiography.

Results:

Time‐resolved CE‐MRA allowed for characterization of malformation flow and type. Feeding and draining vessels were identified in all cases. Overall quality for diagnosis and treatment planning was 3.58/4.0, and correlation with conventional angiography was scored as 3.89/4.0.

Conclusion:

The CAPR time series has been shown to portray the temporal dynamics and structure of vascular malformations as well as the normal vasculature with high quality. CAPR time‐resolved imaging is able to accurately characterize high and low flow lesions, allowing for pretreatment lesion assessment and treatment planning. Delayed imaging is important to capture complete filling of very slow flow vascular malformations. J. Magn. Reson. Imaging 2012;36:933–942. © 2012 Wiley Periodicals, Inc.
Selective reduction of nitroaromatic compounds on silver nanoparticles by visible light
Authors: Xia Lixin , Hu Xinhu , Sun Mengtao , Li Jushi , Yang Donghui , Wang Xiaofang , Xu Hongxing
Published: June 2012

For the first time, we report experimentally and theoretically that nitroaromatic compounds, 2,4‐dinitrobenzenethiol and 4‐chloro‐2‐nitrobenzenethiol, on silver sols can be selectively reduced to 2‐amino‐4‐nitrobenzenethiol and 2‐amino‐4‐chlorobenzenethiol simply by irradiating with a visible light in ambient conditions, and the selective photoreduction is a very facile process. The results of quantum chemical calculations are in good agreement with our experimental data. Copyright © 2012 John Wiley & Sons, Ltd.
Progression and management of Wegener's granulomatosis in the head and neck
Authors: Taylor Stanford C. , Clayburgh Daniel R. , Rosenbaum James T. , Schindler Joshua S.
Published: June 2012

Objectives/Hypothesis:

To describe the otolaryngologic presentation and natural history of granulomatosis with polyangiitis (GPA), previously known as Wegener's granulomatosis, and to compare otolaryngologic outcomes of patients with systemic GPA to those with a limited form of GPA confined to the head and neck.

Study Design:

Retrospective chart review.

Methods:

Review of GPA cases (identified by serology, biopsy, or clinical presentation) seen in the otolaryngology department of an academic medical center.

Results:

A total of 24 patients were identified; each patient was followed for an average 6.8 years. Sinusitis and subglottic stenosis were the most commonly observed head and neck manifestations at diagnosis, seen in 64% and 36%, respectively. Over time, disease spread to additional sites in more than half the cohort (n = 14), but only two of 13 patients with disease initially limited to the head and neck developed pulmonary disease, and none developed renal disease. Cumulatively, otitis media was more likely to be observed in patients with systemic disease (P = .04). Patients with localized (n = 12) and systemic (n = 12) GPA did not have significantly different rates of surgical interventions (0.55 vs. 0.72 surgical interventions/patient‐year of follow‐up, respectively, P = .19).

Conclusions:

GPA has a variety of head and neck manifestations, most commonly sinusitis, nasal disease, subglottic stenosis, and otitis media. GPA commonly progresses to involve additional sites, regardless of the extent of disease. These patients require frequent surgical intervention, and the clinician should remain vigilant for progression of disease.
A pilot study of segmental mandibulectomy with surgical navigation using fluorine‐18 fluorodeoxyglucose positron‐emission tomography/computed tomography
Authors: Chien Chih‐Yen , Chuang Hui‐Ching , Huang Shu‐Hua , Lin Wei‐Che , Huang Husan‐Ying
Published: June 2012

Objectives/Hypothesis:

To evaluate the efficacy of treating lower gum cancer using fluorine‐18 fluorodeoxyglucose positron‐emission tomography/computed tomography ([18] F‐FDG PET/CT) surgical navigation to control bony margins during segmental mandibulectomy.

Study Design:

This study was conducted between September 2010 and June 2011 in a tertiary referral center in southern Taiwan.

Methods:

Segmental mandibulectomy was performed using surgical navigation via [18] F‐FDG PET/CT. Bony margins after decalcification, the 1‐year survival rate, and local control rate were evaluated.

Results:

Ten cases of advanced lower gum cancer in male patients were treated by mandibulectomy, and the bony margins required to excise all neoplastic cells were negative in all cases by using surgical navigation. The minimal distance from the tumor border to the bony incision was 2 cm (2.0–2.9 cm). The mean follow‐up period was 15.2 months (range, 6–24 months) with a 1‐year survival rate of 90% and local control rate of 100%.

Conclusions:

The segmental mandibulectomy aided by surgical navigation with [18] F‐FDG PET/CT guidance is simple and feasible to ensure adequate bony margins intraoperatively, but more patients are necessary to support these findings.
Intrinsically Fluorescent Microspheres with Superior Thermal Stability and Broad Ultraviolet‐Visible Absorption Based on Hybrid Polyphosphazene Material
Authors: Pan Tingjun , Huang Xiaobin , Wei Hao , Wei Wei , Tang Xiaozhen
Published: June 2012

More and more attention is focused on monodispersed, functionalized microspheres with tunable size. In this article, a facile, efficient self‐assembly process is successfully developed to fabricate novel monodispersed microspheres based on hybrid polyphosphazene, and the size of the microspheres is proven to be easily tailorable. The polymer exhibits excellent thermal and intrinsically fluorescent properties which make up the deficiency of generally fluorescent material prepared by embedding with quantum dots or dyes in some special domains. In addition, a broad ultraviolet‐visible absorption is observed from 300 to 450 nm, and all these superior properties may result in potential applications in ablation‐resistant materials, solar energy photoelectric materials and biomaterials.
Highly Defined Multiblock Copolypeptoids: Pushing the Limits of Living Nucleophilic Ring‐Opening Polymerization
Authors: Fetsch Corinna , Luxenhofer Robert
Published: June 2012

Advanced macromolecular engineering requires excellent control over the polymerization reaction. Living polymerization methods are notoriously sensitive to impurities, which makes a practical realization of such control very challenging. Reversible‐deactivation radical polymerization methods are typically more robust, but have other limitations. Here, we demonstrate by repeated (≥10 times) chain extension the extraordinary robustness of the living nucleophilic ring‐opening polymerization of N‐substituted glycine N‐carboxyanhydrides, which yields polypeptoids. We observe essentially quantitative end‐group fidelity under experimental conditions that are comparatively easily managed. This is employed to synthesize a pentablock quinquiespolymer with high definition.
Partial regularity of suitable weak solutions to the four‐dimensional incompressible magneto‐hydrodynamic equations
Authors: Han Pigong , He Cheng
Published: June 2012

In this paper, we study the partial regularity of suitable weak solutions to the incompressible magneto‐hydrodynamic equations in dimension four by borrowing and improving the arguments given by Caffarelli, Kohn, and Nirenberg for incompressible Navier–Stokes equations. The so‐called ε‐regularity criteria are established for suitable weak solutions. As an application, an estimate on Hausdorff dimension of the possible singular points set for a suitable weak solution is given. Finally, we present further information on distribution of the possible singular points if the given initial data decay sufficiently rapidly or are not too singular at the origin, in some sense. Copyright © 2012 John Wiley & Sons, Ltd.
Does patient age impact outcomes of neuromodulation?
Authors: Peters Kenneth M. , Killinger Kim A. , Gilleran Jason , Boura Judith A.
Published: June 2012

Aims

We evaluated whether patients stratified by age have the same level of risks/benefits after a staged neuromodulation procedure for refractory voiding symptoms.

Methods

Urologic diagnosis, complications, and revisions were collected from medical records of adults enrolled in our prospective observational study. Symptoms were assessed over 2 years with diaries, Interstitial Symptom‐Problem Indices (ICSI‐PI), and the Overactive Bladder Questionnaire‐SF (OAB‐q SF). 12‐item Short‐Form Health Survey (SF‐12v2®) mental (MCS) and physical (PCS) component summaries evaluated quality of life. Data were examined with Pearson Chi‐square or Fisher's Exact test, Kruskal‐Wallis tests, and repeated measures analyses.

Results

Patients (83% female) were grouped by age (years): <40 (n = 46), 40–64 (n = 146), and ≥65 (n = 136). Urge incontinence was predominant in the older groups and more patients <40 had interstitial cystitis/painful bladder syndrome (IC/PBS). In the <40, 40–64, and ≥65 groups, respectively, generator implant (91%, 88%, and 89%) and explant (15%, 12%, and 10%) rates were similar. Complications (24%, 14%, and 9%; P = 0.031) and revisions (20%, 5%, and 6%; P = 0.0025) differed. For the three respective groups, urinary frequency (P < 0.0001 for all), nocturia (P < 0.0001 for all), incontinence episodes (P < 0.0001 for all), urgency (P = 0.0474, P < 0.0001, P = 0.0020), ICSI‐PI (P = 0.0015, P < 0.0001, P < 0.0001), and OAB‐q scores improved over time. Incontinence severity improved in those >65 (P = 0.0015). SF‐12 PCS improved in those 40–64 (P = 0.0482) and MCS scores improved in the <40 and 40–64 age groups (P = 0.013 and P = 0.0440, respectively).

Conclusions

These data suggest that neuromodulation success is not age dependent, however continued study is needed to confirm findings. Neurourol. Urodynam. 32: 30–36, 2013. © 2012 Wiley Periodicals, Inc.
Tramadol enhances urethral continence function through µ‐opioid receptors in rats
Authors: Oyama Tatsuya , Kawai Yuko , Oka Michiko
Published: June 2012

Aims

(±)‐Tramadol hydrochloride (tramadol) is a widely used analgesic that stimulates the µ‐opioid receptor and inhibits the reuptake of serotonin and noradrenalin. Although tramadol is also known to inhibit the micturition reflex in rats, its effects on urethral continence function have not been reported. We therefore examined whether intravenous tramadol (1, 3, and 10 mg/kg) affects intraurethral pressure, bladder leak point pressure, and leak volume in urethane‐anesthetized female rats.

Methods

(1) The intraurethral pressure was recorded with a microtip pressure transducer placed at the maximum pressure zone of the intrinsic urethral sphincter. (2) Gentle pressure was directly applied to the saline‐filled bladder with a cotton bud until leakage occurred, and the bladder pressure at the moment of leakage was taken as the bladder leak point pressure. (3) The leak volume was measured as the amount of fluid leakage from the urethral orifice after electrical stimulation of abdominal muscles.

Results

Tramadol significantly increased the intraurethral pressure. Both tramadol and morphine increased the bladder leak point pressure and decreased the leak volume. These changes were reversed by subcutaneous pretreatment with naloxone.

Conclusions

Tramadol improved urethral function and inhibited urinary incontinence through µ‐opioid receptors. Neurourol. Urodynam. 32: 98–103, 2013. © 2012 Wiley Periodicals, Inc.
The association between overactive bladder and fibromyalgia syndrome: A community survey
Authors: Chung Jae Hoon , Kim Shin Ah , Choi Bo Youl , Lee Hye‐Soon , Lee Seung Wook , Kim Yong Tae , Lee Tchun Yong , Moon Hong Sang
Published: June 2012

Aims

Fibromyalgia syndrome (FMS) is the most common disease causing chronic generalized pain, and FMS patients often complain of urinary symptoms such as frequency or urgency. This study focuses on the association of overactive bladder (OAB) and FMS in adults aged 40 and over.

Methods

A survey of adults aged 40s and over was conducted in the Guri and Yangpyeong areas of South Korea. The response rate was 74.2% (940/1,266). After excluding subjects with incomplete questionnaires (n = 20), 920 were included in the final analysis. The association of FMS and OAB was analyzed by univariate and multivariate logistic regression analysis.

Results

Individuals with FMS had a significantly increased symptoms of OAB after adjustment for gender, age group, and area of residence (odds ratio (OR) 3.39, 95% confidence interval (CI) 1.82–6.31). The association between FMS and severity of OAB was statistical significant (P for trend <0.0001).

Conclusions

OAB is associated with FMS. Moreover FMS increases with severity of OAB. Neurourol. Urodynam. 32: 66–69, 2013. © 2012 Wiley Periodicals, Inc.
Pudendal neuromodulation improves voiding efficiency in diabetic rats
Authors: Chen Shih‐Ching , Lai Chien‐Hung , Fan Wen‐Jia , Peng Chih‐Wei
Published: June 2012

Aims

Diabetic cystopathy is typically manifested as bladder voiding dysfunction, and numerous patients are refractory to standard therapy. In this study, we determined whether electrical stimulation (ES) of the sensory branch of the pudendal nerve could engage an augmenting reflex and thereby improve bladder emptying in a diabetic animal model with cystopathy.

Methods

The efficiency of bladder emptying with ES of the sensory branch of the pudendal nerve at different stimulation intensities was measured in rats at 8 or 18 weeks after the induction of diabetes with streptozotocin.

Results

The voiding efficiency (VE) was reduced from 74 ± 4% to 30 ± 8% in rats with diabetes for 8 weeks and from 73 ± 6% to 20 ± 6% in rats with diabetes for 18 weeks. ES at lower intensities (0.025–0.05 mA) applied to the pudendal sensory nerve did not affect the VE in rats with diabetes for 18 weeks but increased the VE in rats with diabetes for 8 weeks. Subsequently, when the stimulation intensity was elevated to 0.1–0.3 mA, the VEs in rats with diabetes for both 8 and 18 weeks increased to 40–50%.

Conclusions

The results of the present study are consistent with the essential role for pudendal sensory feedback in efficient bladder emptying, and electrical activation of the sensory branch of the pudendal nerve was efficient restoring the voiding function in diabetic animals with cystopathy. This could provide an approach to improve bladder emptying in diabetic patients with voiding dysfunction. Neurourol. Urodynam. 32: 293–300, 2013. © 2012 Wiley Periodicals, Inc.
Static, free vibration, and buckling analysis of laminated composite Reissner–Mindlin plates using NURBS‐based isogeometric approach
Authors: Thai Chien H. , Nguyen‐Xuan H. , Nguyen‐Thanh N. , Le T‐H. , Nguyen‐Thoi T. , Rabczuk T.
Published: June 2012

This paper presents a novel numerical procedure based on the framework of isogeometric analysis for static, free vibration, and buckling analysis of laminated composite plates using the first‐order shear deformation theory. The isogeometric approach utilizes non‐uniform rational B‐splines to implement for the quadratic, cubic, and quartic elements. Shear locking problem still exists in the stiffness formulation, and hence, it can be significantly alleviated by a stabilization technique. Several numerical examples are presented to show the performance of the method, and the results obtained are compared with other available ones. Copyright © 2012 John Wiley & Sons, Ltd.
Unilever's strategic response to sustainable development and its implications for public affairs professionals
Authors: Lingard Thomas
Published: June 2012

Unilever is often cited as one of the organisations that is most sophisticated in thinking about and responding strategically to the range of global trends we tend to put under the heading ‘sustainable development’. This paper explores the rationale in Unilever for doing this and looks at the implications it has for Public Affairs. Taking a step back from this and thinking about the historical role of the public affairs professional, and about what Unilever and others are beginning to do, the changing role of the public affairs professional is discussed.

In this article, Thomas Lingard talks to JPA SI guest editor Matthew Gitsham. Copyright © 2012 John Wiley & Sons, Ltd.
Dynamic viscoelasticity behaviors of magnesium dimethacrylate/natural rubber composites with different cure extent
Authors: Xu Chuanhui , Chen Yukun , Cao Liming , Zeng Xingrong
Published: June 2012

In this article, the dynamic viscoelasticity characteristics of the natural rubber (NR)/magnesium dimethacrylate (MDMA) composites with different cure extent are investigated using a Rubber Process Analyzer 2000 (RPA2000). A weak filler–filler network of MDMA is formed in the uncured compounds. MDMA polymerize during peroxide curing and change to the polymerized MDMA (PMDMA), which can aggregate to form strong filler network in the lightly cured composite. The ionic crosslinks and NR crosslinks influence the dynamic viscoelasticity characteristics of the MDMA/NR composites with different cure extent significantly. Although the PMDMA aggregates have strong attraction with each other to form filler network, the ionic crosslinks are not favorable to rebuild the PMDMA network when the NR crosslink network is mature. Finally, the torque verifies that the ionic crosslinks can be influenced by small strain magnitudes (<0.1°) whereas the NR crosslink network is not influenced. POLYM. COMPOS., 2012. © 2012 Society of Plastics Engineers
Use of magnetic resonance imaging in prenatal prognosis of the fetus with isolated left congenital diaphragmatic hernia
Authors: Victoria Teresa , Bebbington Michael W. , Danzer Enrico , Flake Alan W. , Johnson Mark P. , Dinan David , Adzick N. Scott , Hedrick Holly L.
Published: June 2012

Objectives

To investigate the prognostic value of magnetic resonance‐calculated fetal lung volumes (FLV) in fetuses with isolated left congenital diaphragmatic hernia (L‐CDH) who receive standardized prenatal and postnatal care at a single institution.

Materials and methods

A retrospective review was undertaken to identify fetuses with isolated L‐CDH between 2001 and 2010.

Results

Eighty‐five cases of isolated L‐CDH were identified. The overall survival was 65% (55/85). Survival was 45% if there was ‘liver up’ (23/51) and 94% if there was ‘liver down’ (32/34). Univariate statistical analysis showed that ‘liver up’ (p = 0.001), lung‐to‐head ratio (LHR) at diagnosis (p = 0.009), observed/expected (O/E) LHR (p = 0.01), total FLV (p = 0.03), right LV (p = 0.04), magnetic resonance imaging (MRI) observed versus expected (O/E) FLV (p = 0.002), intrathoracic versus intraabdominal stomach (p = 0.002), percentage of herniated liver (p = 0.004), and postnatal extracorporeal membrane oxygenation use (p = 0.001) are predictive of postnatal survival. Multivariate analysis of only prenatal factors showed that the most important determinants of postnatal outcome are percentage of herniated liver, presence of liver up, and MRI O/E FLV.

Conclusion

Herniated intrathoracic liver expressed as ‘liver up’ or as percent herniated liver and MRI measurement of FLV expressed as a O/E ratio are strong prenatal indicators of postnatal survival. © 2012 John Wiley & Sons, Ltd.
Avalanche breakdown in multicrystalline solar cells due to preferred phosphorous diffusion at extended defects
Authors: Bauer Jan , Lausch Dominik , Blumtritt Horst , Zakharov Nikolai , Breitenstein Otwin
Published: June 2012

Multicrystalline solar cells break down strongly at reverse voltages well below the theoretical limit. Previous explanations were based on assuming a constant depth of the junction below the surface. In this work, preferred phosphorous diffusion at special line defects in grain boundaries is shown to lead to spikes in the p–n junctions even below flat surfaces. The curvature radii of the spherical p–n junction bending are measured by electron beam‐induced current to be in the range of 300–500 nm, leading to the observed type III avalanche breakdown voltages. Copyright © 2012 John Wiley & Sons, Ltd.
Rational basis for the combination of PCA3 and TMPRSS2:ERG gene fusion for prostate cancer diagnosis
Authors: Robert Grégoire , Jannink Sander , Smit Frank , Aalders Tilly , Hessels Daphne , Cremers Ruben , Mulders Peter F. , Schalken Jack A.
Published: June 2012

BACKGROUND

The prostate cancer gene 3 (PCA3) and TMPRSS2:ERG gene fusion are promising prostate cancer (PCa) specific biomarkers. Our aim was to simultaneously quantify the expression levels of PCA3 and TMPRSS2:ERG in a panel of benign prostatic hyperplasia (BPH), normal prostate adjacent to PCa (NP) and PCa tissue samples, to provide a rational basis for the understanding of the false‐positive and false‐negative results of the urine assays.

METHODS

The tissue samples were carefully histopathologically characterized to obtain homogeneous groups. The mRNA was isolated, transcribed into cDNA and the relative expressions of PCA3 and TMPRSS2:ERG were measured using a quantitative real‐time polymerase chain reaction. The expression levels of PCA3 and TMPRSS2:ERG were compared between the different groups.

RESULTS

We included 48 BPH, 32 NP, and 48 PCa. The PCA3 expression levels progressively increased from BPH to NP (3 times) and finally to PCa (30 times). There were one false‐positive sample and seven false‐negative samples. The TMPRSS2:ERG gene fusion was found in 8.3% of the BPH, 15.6% of the NP, and 50% of the PCa samples. The use of TMPRSS2:ERG in the PCA3 negative cases allowed diagnosis of four of the seven false‐negative samples and added one false‐positive, but we had to define a cut‐off value to avoid eight false‐positive results.

CONCLUSIONS

Considering tissue expression of the markers, most of the false‐negative results of the PCA3 test were corrected by TMPRSS2:ERG (57%) and the combination of both had a higher sensitivity for PCa diagnosis. Some of the control samples did express TMPRSS2:ERG and a cut‐off value had to be defined to avoid false‐positive results. Prostate 73: 113–120, 2013. © 2012 Wiley Periodicals, Inc.
Global and local quantitative structure–property relationship models to predict the impact sensitivity of nitro compounds
Authors: Fayet Guillaume , Rotureau Patricia , Prana Vinca , Adamo Carlo
Published: June 2012

New quantitative structure–property relationships were developed to predict accurately the impact sensitivity of nitro compounds from their molecular structures. Such predictive approaches represent good alternative to complete experimental testing in development process or for regulatory issues (e.g., within the European REACH regulation).

To achieve highly predictive models, two approaches were used to explore the whole diversity of nitro compounds included in a dataset of 161 molecules. In the first step, local models, dedicated to nitramines, nitroaliphatics, and nitroaromatics, were proposed. After that, a global model was developed to be applicable for the whole range of the nitro compounds of the dataset.

In both cases, large series of molecular descriptors were calculated from quantum chemically calculated molecular structures, and multilinear regressions were computed to correlate them with experimental impact sensitivities. Both the global and local models could predict nitramines and nitroaliphatics in high accuracy whereas nitroaromatics were more difficult to be predicted due to their complex decomposition mechanisms.

The proposed models were validated in the perspective of potential regulatory use according to the OECD principles, including internal, external validation, and the definition of their applicability domain. So, they could then be used for prediction either separately or in a consensus approach. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012
Low‐temperature synthesis of single‐domain Sr‐hexaferrite particles by solid‐state reaction route
Authors: Sözeri Hüseyin , Baykal Abdülhadi , Ünal Bayram
Published: June 2012

Sr‐hexaferrite particles have been synthesized by conventional solid‐state reaction route at low temperatures by boron addition that is used as an inhibitor for crystal growth. The effect of boron concentration on the structural, magnetic and electrical properties of Sr‐hexaferrite particles are investigated by X‐ray crystallography, scanning electron microscopy, magnetization and conductivity measurements. Saturation magnetization of Sr‐hexaferrite increases up to 1 wt% boron addition, while coercivity becomes maximum with a boron amount of 2 wt%. Then, both magnetic parameters start to decrease with higher boron concentrations. Single‐domain and single‐phase powders have been obtained in the sample containing 1 wt% of boron that is sintered at 1050 °C. Impedance spectroscopies reveal that the dc conductivity increases tremendously with boron addition, while the ac conductivity increases with elevated temperature. The ac conductivity obeys roughly the power law of angular frequency in which tendencies change with temperature at low and medium temperature. Furthermore, higher contents of the dopant over approximately 2.0 wt% cause its temperature independency at higher frequencies. These are due to the grain size and secondary phase of hexaferrites that increases with the increase in boron amount.
Polybenzimidazole‐decorated carbon nanotube: A high‐performance proton conductor
Authors: Majedi Fatemeh Sadat , Hasani‐Sadrabadi Mohammad Mahdi , Dashtimoghadam Erfan , Haghighi Amir Hossein , Bertsch Arnaud , Moaddel Homayoun , Renaud Philippe
Published: June 2012

Interaction between negatively charged Nafion® and a positively charged polybenzimidazole‐decorated carbon nanotube leads to the formation of an ionic complex with high charge density for proton conduction, which can lead to an improvement in transport properties. Here we investigate the high‐temperature and low‐humidity proton conductivity of this nanocomposite membrane as a potential membrane for fuel cell applications.

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(© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Hydrogen bonds between acetylene and formic acid: An ab initio study
Authors: Belarmino M. K. D. L. , Lima N. B. D. , Ramos M. N.
Published: June 2012

Theoretical calculations using both the second‐order Møller–Plesset and B3LYP levels of calculation with the 6‐31++G(d,p) and 6‐311++G(3df,3pd) basis sets were performed to determine stable structures, binding energies, and molecular properties for the H‐bonded complexes involving acetylene and formic acid. Three complexes were characterized as minima because no imaginary frequency was found. The calculations indicate that the most stable complex presents two H‐bonds forming a quasi‐cyclic structure. As expected, the HO stretching frequency of the formic acid is shifted downward after complexation, whereas its IR intensity is enormously increased. Finally, we have also studied the R1C2HHOOCR2 H‐bonded complexes with R1 and R2CH3 and C6H5 to compare their binding energies with that obtained to the HCOOHC2H2 complex. In this procedure, we have considered the most stable structure obtained to this latter using the B3LYP theoretical calculations with the 6‐31++G(d,p) basis set. © 2012 Wiley Periodicals, Inc.
Beyond Wigner's theorems: The role of symmetry equivalences in quantum systems
Authors: Zicovich‐Wilson Claudio M. , Erba Alessandro
Published: June 2012

A generalization of the concept of Wigner's symmetrical operator, i.e., of the operator invariant under symmetry transformations forming a group, namely
${\cal G}$, is proposed here. Symmetrical operators in the present general sense do constitute a set whose elements are mutually commuting and equivalent to each other under transformations
${S_i} \in {\cal G}$. A generalization of a well known theorem attributed to Wigner is established: for a given operator Â and its equivalent ones Â[i] = Ŝ
ÂŜi, symmetrical as previously defined, it is always possible to find a complete set of common eigenfunctions that form canonical basis sets for representations of
${\cal G}$
induced by the largest subgroup
${\cal H} \subseteq {\cal G}$
whose elements keep Â invariant (the particular case
${\cal H} \equiv {\cal G}$
reduces to Wigner's theorem itself). The formal generalization presented here opens the possibility of describing and exploiting two complementary aspects of symmetry: invariance and equivalence, within a unified theoretical approach. It is also shown that the symmetry properties of the stationary solutions of Boys' localization functional obey a straightforward extension of this theorem. A few examples are provided to highlight the implications of this alternative way to look at symmetry in quantum systems. © 2012 Wiley Periodicals, Inc.
Density functional study on the geometric features and growing pattern of BnPm clusters with n = 1–4, m = 1–4, n + m ≤ 5
Authors: Curotto Verónica Ferraresi , Diez Reinaldo Pis
Published: June 2012

The bonding features of BnPm clusters (n = 1–4, m = 1–4, n + m ≤ 5) are studied within the framework of the density functional theory following a systematic growing mechanism. Some stable geometries are found to agree well with results reported previously in the literature. Other geometries are found to be more stable than structures reported elsewhere for small B/P aggregates. To the best of our knowledge, stable geometries for BP4 are reported for the first time. It is found that small B/P clusters with up to five atoms tend to grow mainly toward nonlinear bidimensional structures. The existence of BB and BP bonds seems to be of importance for the relative stability of clusters as they grow. The growing patterns could be explained mainly in terms of electrophilic attacks of B atoms to BB and BP bonds. It is found that the growing is in general accompanied by geometry reorganization and atomic charge rearrangements. Electrophilic attacks of P atoms to BB bonds seems to be a good alternative to grow for aggregates with many B atoms. Atomic charges derived from molecular electrostatic potentials are useful to understand the growing paths followed in terms of electrophilic or nucleophilic attacks. © 2012 Wiley Periodicals, Inc.
Inverse virtual screening studies of selected natural compounds from cerrado
Authors: Carregal Ana Paula , Comar Moacyr , Alves Stênio Nunes , Siqueira João Máximo de , Lima Luciana A. , Taranto Alex Gutterres
Published: June 2012

Several medicinal plants have been studied in recent years in Brazil. However, despite many efforts, the pharmacological mechanisms of many natural products are still unknown. Several biological assays in vivo and in vitro are needed to further address this issue, which increases the cost of these studies. The main goal of this study was to apply the methodology of inverse virtual screening (IVS), followed by docking studies, and refinement by molecular dynamics (MD) simulation and quantum mechanical/molecular mechanical to determine the pharmacological receptors for five selected natural products with the exception of the benzoxazinone isolated from the exudate of the radicle of the crop species which were mainly isolated from the Cerrado species, obtained from Cerrado, a typical Brazilian biome. Initially, the structures of the natural compounds were generated using the online software program sc‐PDB, which searches for molecular targets deposited in the protein data bank. The ligands were docked against target proteins found in IVS step‐forming complexes, which were refined again using MD simulations by ff03 force field for 1 ns. Finally, the binding energy for each complex was obtained by the ONIOM (PM6:UFF) method. As a result, these calculations suggested possible molecular targets for these natural compounds. Among the targets found were 1EH4, 2A4Z, 1H49, 1JT2, 2BNJ, and 3FW9, which are involved in cancer and rheumatoid arthritis pathologies, indicating that they are promising molecular targets. In this study, we proposed a biological assay for these natural compounds. The results indicate that structural changes may be proposed to generate compounds that are able to bind more strongly to the receptor and become new drug candidates, thus optimizing the search for lead natural compounds. © 2012 Wiley Periodicals, Inc.
Insights into the yield enhancement and ion emission process in metal‐assisted SIMS
Authors: Nittler L. , Delcorte A. , Bertrand P. , Migeon H.‐N.
Published: June 2012

Although nowadays the use of cluster ion sources seems to enhance the secondary ion emission for nearly all materials, the technique of metal‐assisted SIMS can still give further insights in the secondary ion emission process. In this study, the metallization for static SIMS analysis was performed in situ. The combination of a detailed morphology study by SEM, TEM and the secondary yield enhancements in time‐of‐flight SIMS allows to develop a model explaining the secondary yield enhancement in metal‐assisted SIMS. Copyright © 2012 John Wiley & Sons, Ltd.
Organic depth profiling of C60 and C60/phthalocyanine layers using argon clusters
Authors: Mouhib T. , Poleunis C. , Möllers R. , Niehuis E. , Defrance P. , Bertrand P. , Delcorte A.
Published: June 2012

Molecular semiconductor devices, such as light‐emitting diodes and photovoltaic cells, have recently received considerable attention because of their compatibility with flexible substrates and large‐area applications. Because of the importance of the interfacial properties for the performance of the devices, these organic (multi)layers constitute an important field of application for molecular depth profiling by SIMS. In this contribution, we investigate the use of C60n+ and Ar1000–2000+ cluster projectiles at different energies (ranging from 2.5 to 20 keV) as sputter ions for the organic depth profiling of fullerene‐based films and heterojunctions. The bilayers consist of C60 fullerenes on tin phthalocyanine (SnPc), deposited on silicon substrates. Our preliminary results showed that C60 films could not be successfully profiled using C60n+ ions in regular analysis conditions (room temperature). In contrast, with Ar clusters, the depth profiling is successful (except for 20 keV Ar1000) and the sputtered volume shows a linear relationship with the Ar cluster energy. Surprisingly, for a given total energy of the projectiles, Ar2000 sputters approximately two times more than Ar1000. The observations are tentatively explained as being the result of a balance between the sputtering and the cross‐linking efficiency for the different bombardment conditions, larger clusters being expected to naturally induce less cross‐linking than smaller clusters with the same total energy. Copyright © 2012 John Wiley & Sons, Ltd.
The role of operational flexibility in the expansion of international production networks
Authors: Fisch Jan Hendrik , Zschoche Miriam
Published: June 2012

Volatile factor cost developments urge manufacturing firms to increase production efficiency by building up facilities in multiple countries. Differing from previous work that examines the quality of individual locations for investment, the study evaluates the net present value, the growth option value, and the operational flexibility value of the existing production network to predict the establishment of a new site. The results on a sample of 352 German manufacturing firms suggest that the direction, uncertainty, and diversity of labor cost movements in the extant locations influence the propensity to set up a new production subsidiary. Analyzing the international production network after the expansion shows that the new location increases the value of the network regarding these dimensions. Copyright © 2012 John Wiley & Sons, Ltd.
Toxicity of CdTe Quantum Dots on Yeast Saccharomyces Cerevisiae
Authors: Han Xiaole , Lai Lu , Tian Fangfang , Jiang Feng‐Lei , Xiao Qi , Li Yong , Yu Qiuliyang , Li Dongwei , Wang Jia , Zhang Qiumeng , Zhu Bofan , Li Ran , Liu Yi
Published: June 2012

Along with the widespread development of their bioapplications, concerns about the biosafety of quantum dots (QDs) have increasingly attracted intensive attention. This study examines the toxic effect and subcellular location of cadmium telluride (CdTe) QDs with different sizes against yeast Saccharomyces cerevisiae. The innovative approach is based on the combination of microcalorimetric, spectroscopic, electrochemical, and microscopic methods, which allows analysis of the toxic effect of CdTe QDs on S. cerevisiae and its mechanism. According to the values of the half inhibitory concentration (IC50), CdTe QDs exhibit marked cytotoxicity in yeast cells at concentrations as low as 80.81 nmol L−1 for green‐emitting CdTe QDs and 17.07 nmol L−1 for orange‐emitting CdTe QDs. QD‐induced cell death is characterized by cell wall breakage and cytoplasm blebbing. These findings suggest that QDs with sizes ranging from 4.1 to 5.8 nm can be internalized into yeast cells, which then leads to QD‐induced cytotoxicity. These studies provide valuable information for the design and development of aqueous QDs for biological applications.
Evidence of Plasmonic Coupling in Gallium Nanoparticles/Graphene/SiC
Authors: Yi Congwen , Kim Tong‐Ho , Jiao Wenyuan , Yang Yang , Lazarides Anne , Hingerl Kurt , Bruno Giovanni , Brown April , Losurdo Maria
Published: June 2012

Graphene is emerging as a promising material for plasmonics applications due to its strong light–matter interactions, most of which are theoretically predicted but not yet experimentally realized. Therefore, the integration of plasmonic nanoparticles to create metal nanoparticle/graphene composites enables numerous phenomena important for a range of applications from photonics to catalysis. For these applications it is important to articulate the coupling of photon‐based excitations such as the interaction between plasmons in each of the material components, as well as their charge‐based interactions dependent upon the energy alignment at the metal/graphene interface. These coupled phenomena underpin an active application area in graphene‐based composites due to nanoparticle‐dependent surface‐enhanced Raman scattering (SERS) of graphene phonon modes. This study reveals the coupling of a graphene/SiC support with Ga‐nanoparticle‐localized surface plasmon resonance, which is of particular interest due to its ability to be tuned across the UV into the near‐IR region. This work is the first demonstration of the evolving plasmon resonance on graphene during the synthesis of surface‐supported metal nanoparticles, thus providing evidence for the theoretically predicted screening revealed by a damped resonance with little energy shift. Therefore, the role of the graphene/substrate heterojunction in tailoring the plasmon resonance for nanoplasmonic applications is shown. Additionally, the coupled phenomena between the graphene–Ga plasmon properties, charge transfer, and SERS of graphene vibrational modes are explored.
Options for increasing biomass output from long‐rotation forestry
Authors: Egnell Gustaf , Björheden Rolf
Published: June 2012

Forests managed by long‐rotation forestry already play an important role as a source for renewable biomass and energy. The biomass output from these forests may be increased through higher harvest levels, but to be sustainable over time, harvest levels cannot exceed forest growth. A large proportion of the tree biomass (tops, foliage, branches, stumps, and small and unmerchantable trees) is left on the logging site in conventional stemwood harvest, representing a considerable amount of available biomass. The realizable biomass potential is lower, due to environmental and techno‐economic constraints. If more technically adapted, efficient, and environmentally friendly biomass harvest and transport systems are developed, the realized biomass potential can be considerably increased. By complementing current stemwood harvesting technologies with systems that include logging residues, stumps, and small trees, a larger proportion of the potential will be available. In a longer term, increased forest growth can raise the biomass output. Many silvicultural treatments are available, including improved site preparation, vegetation control, insect control, browser control, genetically improved seedlings, fast growing tree species, fertilization, irrigation, denser stands, and so on. Inexpensive silvicultural measures that can be applied on large areas at a fast rate, such as using genetically improved seedling stock, have the highest potential to increase total forest production. Because of the long‐rotation periods, it will take decades to make a difference in forest production and thereby in the biomass output potential. In addition, a more efficient use of biomass in both forest and energy industries and in biorefineries of the future holds potential. © 2012 John Wiley & Sons, Ltd.

This article is categorized under:

Bioenergy > Science and Materials

Bioenergy > Economics and Policy

Bioenergy > Systems and Infrastructure
The messenger sector of SUSY flavour models and radiative breaking of flavour universality
Authors: Calibbi Lorenzo , Lalak Zygmunt , Pokorski Stefan , Ziegler Robert
Published: June 2012

Abstract

The flavour messenger sectors and their impact on the soft SUSY breaking terms are investigated in SUSY flavour models. In the case when the flavour scale M is below the SUSY breaking mediation scale M
S , the universality of soft terms, even if assumed at M
S , is radiatively broken. We estimate this effect in a broad class of models. In the CKM basis that effect gives flavour off-diagonal soft masses comparable to the tree-level estimate based on the flavour symmetry.
Daily energy expenditure in precocial shorebird chicks: smaller species perform at higher levels
Authors: Krijgsveld Karen L. , Ricklefs Robert E. , Visser G. Henk
Published: June 2012

We measured daily energy expenditure (DEE) during the development periods of precocial chicks of five species of Arctic shorebirds spanning a broad range in size, in order to investigate the relationships between DEE, body size, and growth rate. We also quantified the effect of weather conditions on the energy expenditure of chicks to establish the impact of cold arctic weather on their time and energy budgets. We used the doubly labeled water method to measure DEE at ambient temperatures in an outside enclosure on the subarctic tundra at Churchill, Manitoba, Canada. Growth rate was highest in the smallest species, and in general decreased with adult size, as shown by the decrease in growth rate constant and later inflection point with increasing adult body mass. DEE ranged from 14 kJ day−1in young chicks of the smaller species to 365 kJ day−1in older chicks of the larger species. From hatching onward, DEE of shorebirds was high compared to DEE of chicks of altricial species, reflecting the high costs of locomotion and thermoregulation, and mass-specific DEE increased rapidly to adult levels. Chicks of smaller species metabolized more energy per unit mass and functioned at higher multiples of resting metabolic rate than chicks of larger species. As chicks of smaller species also had higher growth rates, and thus simultaneously invested in growth and mature function, it seems that shorebird chicks can adjust total metabolizable energy as well as its relative allocation between investment in growth and mature function. DEE was similar to cold-induced peak metabolic rates achieved by shivering thermogenesis. Because chicks were motionless during laboratory metabolism measurements, the relatively high level of DEE compared to these metabolic rates suggests that locomotion produces similar amounts of heat as shivering. Ambient temperature did not affect DEE in outdoor pens, although higher wind speed resulted in slightly increased energy expenditure. Heat produced by locomotion is possibly sufficient to sustain thermoregulation under local environments. Furthermore, when ambient temperatures are low, chicks spend more time brooding and less time foraging, which presumably counters the tendency to increase thermogenesis in response to cold.
Polygyny, Partnership Concurrency, and HIV Transmission in Sub-Saharan Africa
Authors: Reniers Georges , Tfaily Rania
Published: June 2012

We study the relationship between polygyny and HIV infection using nationally representative survey data with linked serostatus information from 20 African countries. Our results indicate that junior wives in polygynous unions are more likely to be HIV positive than spouses of monogamous men, but also that HIV prevalence is lower in populations with more polygyny. With these results in mind, we investigate four explanations for the contrasting individual- and ecological-level associations. These relate to (1) the adverse selection of HIV-positive women into polygynous unions, (2) the sexual network structure characteristic of polygyny, (3) the relatively low coital frequency in conjugal dyads of polygynous marriages (coital dilution), and (4) the restricted access to sexual partners for younger men in populations where polygynous men presumably monopolize the women in their community (monopolizing polygynists). We find evidence for some of these mechanisms, and together they support the proposition that polygynous marriage systems impede the spread of HIV. We relate these results to the debate about partnership concurrency as a primary behavioral driver for the fast propagation of HIV in some parts of sub-Saharan Africa.
Mortality From the Influenza Pandemic of 1918–1919: The Case of India
Authors: Chandra Siddharth , Kuljanin Goran , Wray Jennifer
Published: June 2012

Estimates of worldwide mortality from the influenza pandemic of 1918–1919 vary widely, from 15 million to 100 million. In terms of loss of life, India was the focal point of this profound demographic event. In this article, we calculate mortality from the influenza pandemic in India using panel data models and data from the Census of India. The new estimates suggest that for the districts included in the sample, mortality was at most 13.88 million, compared with 17.21 million when calculated using the assumptions of Davis (1951). We conclude that Davis’ influential estimate of mortality from influenza in British India is overstated by at least 24%. Future analyses of the effects of the pandemic on demographic change in India and worldwide will need to account for this significant downward revision.