bluuebunny/crossref_metadata_2025 huggingface dataset:
Photosensor Device Based on Few‐Layered WS2 Films
Authors: Perea‐López Néstor , Elías Ana Laura , Berkdemir Ayse , Castro‐Beltran Andres , Gutiérrez Humberto R. , Feng Simin , Lv Ruitao , Hayashi Takuya , López‐Urías Florentino , Ghosh Sujoy , Muchharla Baleeswaraiah , Talapatra Saikat , Terrones Humberto , Terrones Mauricio
Published: June 2013

Few‐layered films of WS2, synthesized by chemical vapor deposition on quartz, are successfully used as light sensors. The film samples are structurally characterized by Raman spectroscopy, atomic force microscopy, scanning electron microscopy, and high‐resolution transmission electron microscopy. The produced samples consist of few layered sheets possessing up to 10 layers. UV–visible absorbance spectra reveals absorption peaks at energies of 1.95 and 2.33 eV, consistent with the A and B excitons characteristic of WS2. Current–voltage (I–V) and photoresponse measurements carried out at room temperature are performed by connecting the WS2 layered material with Au/Ti contacts. The photocurrent measurements are carried out using five different laser lines ranging between 457 and 647 nm. The results indicate that the electrical response strongly depends on the photon energy from the excitation lasers. In addition, it is found that the photocurrent varies non‐linearly with the incident power, and the generated photocurrent in the WS2 samples varies as a squared root of the incident power. The excellent response of few‐layered WS2 to detect different photon wavelengths, over a wide range of intensities, makes it a strong candidate for constructing novel optoelectronic devices.
Tuning Molecular Self‐Assembly on Bulk Insulator Surfaces by Anchoring of the Organic Building Blocks
Authors: Rahe Philipp , Kittelmann Markus , Neff Julia L. , Nimmrich Markus , Reichling Michael , Maass Philipp , Kühnle Angelika
Published: June 2013

Molecular self‐assembly constitutes a versatile strategy for creating functional structures on surfaces. Tuning the subtle balance between intermolecular and molecule‐surface interactions allows structure formation to be tailored at the single‐molecule level. While metal surfaces usually exhibit interaction strengths in an energy range that favors molecular self‐assembly, dielectric surfaces having low surface energies often lack sufficient interactions with adsorbed molecules. As a consequence, application‐relevant, bulk insulating materials pose significant challenges when considering them as supporting substrates for molecular self‐assembly. Here, the current status of molecular self‐assembly on surfaces of wide‐bandgap dielectric crystals, investigated under ultrahigh vacuum conditions at room temperature, is reviewed. To address the major issues currently limiting the applicability of molecular self‐assembly principles in the case of dielectric surfaces, a systematic discussion of general strategies is provided for anchoring organic molecules to bulk insulating materials.
Nondestructive Verification of Gamma Irradiation Effectiveness for Securing Paper Originality
Authors: Bakr W. F. , Rohayem Said
Published: June 2013

The aim of this research is to verify and validate the gamma irradiation technology as a new technique for security paper's authenticity. Different techniques such as Fourier transform infrared and electron spin resonance are used to verify the procedures and to distinguish between papers. The paper handsheets were irradiated at National Center for Radiation Research and Technology using a 60Co gamma cell with five radiation doses, ranging from 3 to 15 kGy, at the dose rate of 0.817 Gy/s. The properties of paper handsheets were tested before and after irradiation. This study presents a new application of peaceful uses of atomic energy in authentication and avoidance of counterfeiting of security papers. © 2013 Wiley Periodicals, Inc. Adv Polym Technol 2013, 32, 21359; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.21359
Potential years of life lost (PYLL) caused by asbestos‐related diseases in the world
Authors: Diandini Rachmania , Takahashi Ken , Park Eun‐Kee , Jiang Ying , Movahed Mehrnoosh , Le Giang Vinh , Lee Lukas Jyuhn‐Hsiarn , Delgermaa Vanya , Kim Rokho
Published: June 2013

Background

We applied the well‐established, but rather under‐utilized, indicator of Potential Years of Life Lost (PYLL) to estimate the global burden of mesothelioma and asbestosis.

Methods

We analyzed all deaths caused by mesothelioma and asbestosis that were reported by 82 and 55 countries, respectively, to the World Health Organization (WHO) from 1994 to 2010.

Results

The 128,015 and 13,885 persons who died of mesothelioma and asbestosis, potentially lost a total of 2.18 million and 180,000 years of life (PYLL), or, an annual average PYLL of 201,000 years and 17,000 years, respectively. The average PYLL per decedent were 17.0 and 13.0 years for mesothelioma and asbestosis, respectively.

Conclusions

The current burden of asbestos‐related diseases (ARDs) in terms of PYLL is substantial. The future burden of ARDs can be eliminated by stopping the use of asbestos. Am. J. Ind. Med. 56:993–1000, 2013. © 2013 Wiley Periodicals, Inc.
Combining Spontaneous Polymerization and Click Reactions for the Synthesis of Polymer Brushes: A “Grafting Onto” Approach
Authors: Cappelli Andrea , Grisci Giorgio , Paolino Marco , Castriconi Federica , Giuliani Germano , Donati Alessandro , Lamponi Stefania , Mendichi Raniero , Boccia Antonella Caterina , Samperi Filippo , Battiato Salvatore , Paccagnini Eugenio , Gentile Mariangela , Licciardi Mariano , Giammona Gaetano , Vomero Salvatore
Published: June 2013

Two novel benzofulvene monomers bearing propargyl or allyl groups have been synthesized by means of readily accessible reactions, and were found to polymerize spontaneously by solvent removal, in the apparent absence of catalysts or initiators, to give the corresponding polybenzofulvene derivatives bearing clickable propargyl or allyl moieties. The clickable propargyl and allyl groups were exploited in appropriate click reactions to develop a powerful and versatile “grafting onto” synthetic methodology for obtaining tailored polymer brushes.
Synthesis of Cationic R2P5+ Cages and Subsequent Chalcogenation Reactions
Authors: Holthausen Michael H. , Hepp Alexander , Weigand Jan J.
Published: June 2013

Cationic R2P5+ cage compounds (1+) have been synthesized by the stoichiometric reaction of R2PCl, GaCl3 and P4. The reaction conditions depend on the substituent R. Alkyl‐substituted derivatives (1 a–1 d[GaCl4]) are best synthesized under solvent‐free conditions, whereas aryl‐substituted derivatives (1 e–1 h[GaCl4]) are formed in C6H5F. All compounds have been prepared on a multi‐gram scale in good to excellent yields and have been fully characterized with an emphasis on 31P NMR spectroscopy in solution and single‐crystal structure determination. Subsequent chalcogenation reactions of cations R2P5+ (1 a+, 1 e+) and trication Ph6P73+ (33+) with elemental sulfur (α‐S8) or grey selenium (Segrey) yielded a series of unique polyphosphorus–chalcogen cations (4 a+, 4 e+, 5 a+, 62+ and 72+), possessing nortricyclane‐type molecular structures. An in‐depth study of the 31P{1H} and 77Se NMR spectroscopic parameters is presented, and correlations between the substitution pattern and the observed structural features have been investigated in detail.
Spatiotemporal Patterns of Pax3, Pax6, and Pax7 Expression in the Developing Brain of a Urodele Amphibian, Pleurodeles waltl
Authors: Joven Alberto , Morona Ruth , González Agustín , Moreno Nerea
Published: June 2013

The onset and developmental dynamics of Pax3, Pax6, and Pax7 expressions were analyzed by immunohistochemical techniques in the central nervous system (CNS) of embryos, larvae, and recently metamorphosed juveniles of the urodele amphibian Pleurodeles waltl. During the embryonic period, the Pax proteins start being detectable in neuroepithelial domains. Subsequently, they become restricted to subsets of cells in distinct brain regions, maintaining different degrees of expression in late larvae and juvenile brains. Specifically, Pax6 is broadly expressed all along the urodele CNS (olfactory bulbs, pallium, basal ganglia, diencephalon, mesencephalic tegmentum, rhombencephalon, and spinal cord) and the developing olfactory organ and retina. Pax3 and Pax7 are excluded from the rostral forebrain and were usually observed in overlapping regions during embryonic development, whereas Pax3 expression is highly downregulated as development proceeds. Thus, Pax3 is restricted to the roof plate of prosomere 2, pretectum, optic tectum, rhombencephalon, and spinal cord. Comparatively, Pax7 was more conspicuous in all these regions. Pax7 cells were also found in the paraphysis, intermediate lobe of the hypophysis, and basal plate of prosomere 3. Our data show that the expression patterns of the three Pax genes studied are overall evolutionarily conserved, and therefore could unequivocally be used to identify subdivisions in the urodele brain similar to other vertebrates, which are not clearly discernable with classical techniques. In addition, the spatiotemporal sequences of expression provide indirect evidence of putative migratory routes across neuromeric limits and the alar–basal boundary. J. Comp. Neurol. 521:3913–3953, 2013. © 2013 Wiley Periodicals, Inc.
Specmaster: an OpenCL‐based peptide search engine for tandem mass spectrometry
Authors: Weber Rick , Jenkins David D. , Peterson Gregory D.
Published: June 2013

Graphics processing units and multicore processors are now pervasive in computational sciences and high‐performance computing. Their high arithmetic throughput and memory bandwidth combined with their ever increasing programmability make them suitable for a widening variety of applications. We give a high level overview of Specmaster, a Myrimatch port that can use every open computing language device available in a machine to identify peptides in tandem mass spectrometry data. We then highlight device‐specific optimizations for multi‐core CPUs and graphics processing units as well as describe our framework for implementing these optimizations while still using a single code base. We also provide performance results of Specmaster running on four different architectures and compare these numbers with Myrimatch. Finally, we improve on our existing work by showing Specmaster dynamically load‐balancing on 3 Radeon 7970s and 32 Interlagos 6272 cores as well as comparing the quality of our search results with Myrimatch. Copyright © 2013 John Wiley & Sons, Ltd.
Cytometry, immunology, and HIV infection: Three decades of strong interactions
Authors: Cossarizza Andrea , De Biasi Sara , Gibellini Lara , Bianchini Elena , Bartolomeo Regina , Nasi Milena , Mussini Cristina , Pinti Marcello
Published: June 2013

Flow cytometry (FCM) has been extensively used to investigate immunological changes that occur from infection with the human immunodeficiency virus (HIV). This review describes some of the most relevant cellular and molecular changes in the immune system that can be detected by FCM during HIV infection. Finally, it will be discussed how this technology has facilitated the understanding not only of the biology of the virus but also of the mechanisms that the immune system activates to fight HIV and is allowing to monitor the efficacy of antiretroviral therapy. © 2013 International Society for Advancement of Cytometry
Modeling the Glutathione Peroxidase‐Like Activity of a Cyclic Seleninate by DFT and Solvent‐Assisted Proton Exchange
Authors: Bayse Craig A. , Ortwine Kristine N.
Published: June 2013

The mechanism of redox scavenging of a highly active cyclic seleninate was modeled by using density functional theory and solvent‐assisted proton exchange (SAPE), a method of microsolvation intended to mimic the role of the solvent in proton‐transfer reactions. Models of the proposed mechanism suggest that a pathway to a selenenyl sulfide, a possible dead‐end intermediate, is favored over regeneration of the seleninate catalyst. Alternate pathways through selenurane intermediates and a cyclic selenenate also appear to lead to the selenenyl sulfide. Based upon the DFT‐SAPE results, we suggest that the high level of catalysis shown by the cyclic seleninate may be attributed to experimental reaction conditions, in which the excess oxidant ensures that the catalytic cycle bypasses the selenenyl sulfide. Catalysis under less oxidizing conditions are proposed to occur through oxidation of the selenenyl sulfide to the seleninyl sulfide.
A Flexible Strategy Towards Thienyl‐, Oxazolyl‐ and Pyridyl‐Fused Fluorenones
Authors: Souibgui Amel , Gaucher Anne , Marrot Jérôme , Aloui Faouzi , Mahuteau‐Betzer Florence , Ben Hassine Bechir , Prim Damien
Published: June 2013

The preparation of new thienyl‐, oxazolyl‐, and pyridyl‐fused benzo[c]fluorenones has been developed from a unique and easily available common precursor. Starting from bromotetralone, a short sequence allowed the construction of various heterocycles followed by Suzuki coupling and final acid‐promoted formation of the central cyclopentanone unit. The flexible strategy allowed the selective preparation of fused penta‐ to hepta‐cyclic architectures. Fully aromatic targets have been obtained through the application of an oxidation process. The influence of structural modulations on the photophysical properties are described.
A soil quality index for reclaimed mine soils
Authors: Asensio Verónica , Guala S.D. , Vega Flora A. , Covelo Emma F.
Published: June 2013

The quality of soils found in mines is low if they do not receive any reclamation treatment; yet, to the authors' knowledge, there are still no equations to evaluate the quality of metal-contaminated mine soils after the application of the most widely used reclamation treatments (planting vegetation and amending with wastes). Therefore, the purposes of the present study were 1) to propose a method for developing soil quality indexes (SQIs); 2) to develop the SQIs for 2 types of mine soils (settling pond and mine tailing) reclaimed by planting trees, amending with wastes, or both; and 3) to assess the quality of these soils under field conditions. The results obtained after the use of an SQI developed for reclaimed mine soils through the selection of an SQI with a factor analysis and the totaling of the scores of the selected variables revealed that this method is a valid tool for developing SQIs. Applying this index with reclaimed mine soils showed that the untreated sites had a very low quality and that the treatment that most improved the soils was amending with wastes (sewage sludges and paper mill residues). The authors recommend the periodic addition of sewage sludges and paper mill residues to degraded sites as they increase the quality of soils, but the effects decrease over time. Environ Toxicol Chem 2013;32:2240–2248. © 2013 SETAC
The P and S wave velocity structure of the mantle beneath eastern Africa and the African superplume anomaly
Authors: Mulibo Gabriel D. , Nyblade Andrew A.
Published: June 2013

P and S relative arrival time residuals from teleseismic earthquakes recorded on over 60 temporary AfricaArray broadband seismic stations deployed in Uganda, Tanzania, and Zambia between 2007 and 2011 have been inverted, together with relative arrival time residuals from earthquakes recorded by previous deployments, for a tomographic image of mantle wave speed variations extending to a depth of 1200 km beneath eastern Africa. The image shows a low‐wave speed anomaly (LWA) well developed at shallow depths (100–200 km) beneath the Eastern and Western branches of the Cenozoic East African rift system and northwestern Zambia, and a fast wave speed anomaly at depths ≤ 350 km beneath the central and northern parts of the East African Plateau and the eastern and central parts of Zambia. At depths ≥350 km the LWA is most prominent under the central and southern parts of the East African Plateau and dips to the southwest beneath northern Zambia, extending to a depth of at least 900 km. The amplitude of the LWA is consistent with a ∼150–300 K thermal perturbation, and its depth extent indicates that the African superplume, originally identified as a lower mantle anomaly, is likely a whole mantle structure. A superplume extending from the core‐mantle boundary to the surface implies an origin for the Cenozoic extension, volcanism, and plateau uplift in eastern Africa rooted in the dynamics of the lower mantle.
Medium-chain chlorinated paraffins (MCCPs): A review of bioaccumulation potential in the aquatic environment
Authors: Thompson Roy , Vaughan Martin
Published: June 2013

Chlorinated paraffins (CPs) are high molecular weight organochlorine compounds that have been used in a variety of industrial applications for many years. Medium-chain chlorinated paraffins (MCCPs) (CAS 85535-85-9; Alkanes, C14–17, chloro) are currently under investigation as potential persistent bioaccumulative toxic (PBT) compounds. In this article, the bioaccumulation potential of MCCPs is assessed using a tiered framework proposed after a recent Society of Environmental Toxicology and Chemistry (SETAC) Pellston Workshop in 2008. The framework proposes the use of physicochemical properties and modeling assessment, bioconcentration/bioaccumulation (BCF/BAF) assessment, biomagnification (BMF) assessment, and trophic magnification factor (TMF) assessment. It is hoped that use of this framework could harmonize and improve the efficiency and effectiveness of the chemical substance evaluation screening process for PBT properties. When applied to MCCPs, the following conclusions were made: empirical physiochemical data is available negating the use of models; laboratory BCFs range from 1000 to 15 000 (growth-corrected lipid normalized values) for 2 MCCP structures; field BAFs were an order of magnitude higher than the trigger criterion for “B status possible”; although results may not meet acceptance criteria for field studies, laboratory-derived BMFs for a number of C14–17 chlorinated alkanes were less than the trigger value of 1 (based on whole-body concentrations) whereas field-derived BMFs were less than 1 (based on lipid corrected values [generally used for field data] excluding one measure for sculpin, [Cottus cognatus]-Diporeia that was based on only one detectable sample); and finally, TMFs were less than the trigger criterion value of 1, which are considered the most convincing evidence for bioaccumulative properties of a compound and the “Gold Standard” measure of bioaccumulation. This article also discusses the uncertainties surrounding the published data, especially concerning field data where limited sampling points are available and the difficulty in assessing the bioaccumulative potential of MCCPs as mixtures of different congeners. In conclusion, although some laboratory bioaccumulation values have a potential for concern, the majority of field values are more favorable when assessing the bioaccumulative potential of MCCPs. Definitive conclusions on the PBT assessment of MCCPs can be eased with further testing in both areas of P and B in the laboratory in conjunction with further monitoring of biota in the field to derive more robust field data. Integr Environ Assess Manag 2014;10:78–86. © 2013 SETAC
Spending more, doing more, or both? An alternative method for quantifying utilization during hospitalizations
Authors: Lagu Tara , Krumholz Harlan M. , Dharmarajan Kumar , Partovian Chohreh , Kim Nancy , Mody Purav S. , Li Shu‐Xia , Strait Kelly M. , Lindenauer Peter K.
Published: June 2013

BACKGROUND

Because relative value unit (RVU)‐based costs vary across hospitals, it is difficult to use them to compare hospital utilization.

OBJECTIVE

To compare estimates of hospital utilization using RVU‐based costs and standardized costs.

DESIGN

Retrospective cohort.

SETTING AND PATIENTS

Years 2009 to 2010 heart failure hospitalizations in a large, detailed hospital billing database that contains an itemized log of costs incurred during hospitalization.

INTERVENTION

We assigned every item in the database with a standardized cost that was consistent for that item across all hospitals.

MEASUREMENTS

Standardized costs of hospitalization versus RVU‐based costs of hospitalization.

RESULTS

We identified 234 hospitals with 165,647 heart failure hospitalizations. We observed variation in the RVU‐based cost for a uniform “basket of goods” (10th percentile cost $1,552; 90th percentile cost of $3,967). The interquartile ratio (Q75/Q25) of the RVU‐based costs of a hospitalization was 1.35 but fell to 1.26 after costs were standardized, suggesting that the use of standardized costs can reduce the “noise” due to differences in overhead and other fixed costs. Forty‐six (20%) hospitals had reported costs of hospitalizations exceeding standardized costs (indicating that reported costs inflated apparent utilization); 42 hospitals (17%) had reported costs that were less than standardized costs (indicating that reported costs underestimated utilization).

CONCLUSIONS

Standardized costs are a novel method for comparing utilization across hospitals and reduce variation observed with RVU‐based costs. They have the potential to help hospitals understand how they use resources compared to their peers and will facilitate research comparing the effectiveness of higher and lower utilization. Journal of Hospital Medicine 2013;8:373–379. © 2013 Society of Hospital Medicine
SPE–HPLC–MS/MS method for the trace analysis of tobacco‐specific N‐nitrosamines and 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanol in rabbit plasma using tetraazacalix[2]arene[2]triazine‐modified silica as a sorbent
Authors: Wang Lei , Yang Chunqiang , Zhang Qidong , Wang Sheng , Lang Hailei , Zhang Shusheng , Zhao Wenjie , Zhang Jianxun
Published: June 2013

Tobacco‐specific N‐nitrosamines (TSNAs), including N′‐nitrosonornicotine, 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone, N′‐nitrosoanatabine, and N′‐nitrosoanabasine, have been implicated as a source of carcinogenicity in tobacco and cigarette smoke. We present a rapid and effective method comprising SPE based on tetraazacalix[2]arene[2]triazine‐modified silica as sorbent and analysis with HPLC–MS/MS for the determination of TSNAs and 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanol (NNAL), a metabolite of 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone, in rabbit plasma. The linear dynamic ranges were 10–2000 pg/mL for NNAL and 4–2000 pg/mL for the four TSNAs with good correlation coefficients (>0.9965). The LODs were in the range of 0.9–3.7 pg/mL, and the LOQs were between 2.9 and 12.3 pg/mL. The accuracies of the method were also evaluated and found to be in the range of 90.1–113.3%. This method is promising to be applied to the preconcentration and determination of TSNAs and NNAL in smoke and human body fluids.
Determination of abamectin in citrus fruits using SPE combined with dispersive liquid–liquid microextraction and HPLC–UV detection
Authors: Rezaee Mohammad , Mashayekhi Hossein Ali , Saleh Abolfazl , Abdollahzadeh Yaser , Naeeni Mohammad Hosein , Fattahi Nazir
Published: June 2013

A new pretreatment method, SPE combined with dispersive liquid–liquid microextraction, was proposed for the determination of abamectin in citrus fruit samples for the first time. In this method, fruit samples were extracted by ultrasound‐assisted extraction followed by SPE. Then, the SPE was used as a disperser solvent in the next dispersive liquid–liquid microextraction step for further purification and enrichment of abamectin. The effects of various parameters on the extraction efficiency of the proposed method were investigated and optimized. Good linearity of abamectin was obtained from 0.005 to 10.0 mg/kg for B1a and from 0.05 to 10.0 mg/kg for B1b with correlation coefficient (r2) of 0.998 for B1a and 0.991 for B1b, respectively. The LODs were 0.001 and 0.008 mg/kg (S/N = 3) for B1a and B1b, respectively. The relative recoveries at three spiked levels were ranged from 87 to 96% with the RSD less than 11% (n = 3). The method has been successfully applied to the determination of abamectin in citrus fruit samples.
Screening of aromatase inhibitors in traditional Chinese medicines by electrophoretically mediated microanalysis in a partially filled capillary
Authors: Zhao Haiyan , Chen Zilin
Published: June 2013

An electrophoretically mediated microanalysis method with partial filling technique was developed for screening aromatase inhibitors in traditional Chinese medicine. The in‐capillary enzymatic reaction was performed in 20 mM sodium phosphate buffer (pH 7.4), and sodium phosphate buffer (20 mM, pH 8.0) was used as a background electrolyte. A long plug of coenzyme reduced β‐nicotinamide adenine dinucleotide 2′‐phosphate hydrate dissolved in the reaction buffer was hydrodynamically injected into a fused silica capillary followed by the injection of reaction buffer, enzyme, and substrate solution. The reaction was initiated with a voltage of 5 kV applied to the capillary for 40 s. The voltage was turned off for 20 min to increase the product amount and again turned on at a constant voltage of 20 kV to separate all the components. Direct detection was performed at 260 nm. The enzyme activity was directly assayed by measuring the peak area of the produced β‐nicotinamide adenine dinucleotide phosphate and the decreased peak area indicated the aromatase inhibition. Using the Lineweaver–Burk equation, the Michaelis–Menten constant was calculated to be 50 ± 4.5 nM. The method was applied to the screening of aromatase inhibitors from 15 natural products. Seven compounds were found to have potent AR inhibitory activity.
Enhancing the Superhydrophobic State Stability of Chitosan‐Based Coatings for Textiles
Authors: Ivanova Nina A. , Rutberg Galina I. , Philipchenko Anatoly B.
Published: June 2013

A superhydrophobic textile for biomedical applications is designed using chitosan‐based hydrophobic nanoparticles. The fabrication of nanoparticles is based on the electrostatic interaction between the amine group of chitosan and the negatively charged fluoroanion. The coating is formed by spraying the nanoparticles dispersion over the textile surface, while the complementary hydrophobization by functionalized perfluorodecylsilane leads to substitution of hydrophilic surface groups by hydrophobic ones. The crucial role of the relative number of fluoroanions per elementary unit of chitosan in both surface wettability and durability of coatings in contact with aqueous media is demonstrated.

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Interaction of polymorphisms in mitotic regulator genes with cigarette smoking and pancreatic cancer risk
Authors: Jang Ji‐Hyun , Cotterchio Michelle , Borgida Ayelet , Liu Geoffrey , Gallinger Steven , Cleary Sean P.
Published: June 2013

Mitotic regulator genes have been associated with several cancers, however little is known about their possible association with pancreatic cancer. Smoking and family history are the strongest risk factors for this highly fatal disease. The main purpose of this study was to determine if polymorphisms of mitotic regulator genes are associated with pancreatic cancer and whether they modify the association between cigarette smoking and pancreatic cancer risk. A population‐based case‐control study was conducted in Ontario with 455 pathology‐confirmed pancreatic cancer cases and 893 controls. Cigarette smoking history was collected using questionnaires and DNA obtained from blood samples. Genotypes were determined by mass‐spectrometry. Odds ratio estimates were obtained using multivariate logistic regression. Interactions between genetic variant and smoking were assessed using stratified analyses and the likelihood ratio statistic (significance P < 0.05). Variants of MCPH1, FYN, APC, PRKCA, NIN, TopBP1, RIPK1, and SNW1 were not independently associated with pancreatic cancer risk. A significant interaction was observed between pack‐years and MCPH1‐2550‐C > T (P = 0.02). Compared to never smokers, individuals with 10–27 pack‐years and MCPH1‐2550‐CC genotype were at increased risk for pancreatic cancer (MVOR = 2.49, 95% confidence interval [95% CI]: 1.55, 4.00) as were those with >27 pack‐years and MCPH1‐2550‐TC genotype (MVOR = 2.42, 95% CI: 1.45, 4.05). A significant interaction was observed between smoking status and TopBP1‐3257‐A > G (P = 0.04) using a dominant model. Current smokers with the TopBP1‐3257 A allele were at increased risk for pancreatic cancer (MVOR = 2.55, 95% CI: 1.77, 3.67). MCPH1‐2550‐C > T and TopBP1‐3257‐A > G modify the association between smoking and pancreatic cancer. These findings provide insights into the potential molecular mechanisms behind smoking‐associated pancreatic cancer. © 2013 Wiley Periodicals, Inc.
Robust shortest path problems with two uncertain multiplicative cost coefficients
Authors: Kwon Changhyun , Lee Taehan , Berglund Paul
Published: June 2013

We consider a robust shortest path problem when the cost coefficient is the product of two uncertain factors. We first show that the robust problem can be solved in polynomial time by a dual‐variable enumeration with shortest path problems as subproblems. We also propose a path enumeration approach using a K ‐shortest paths finding algorithm that may be efficient in many real cases. An application in hazardous materials transportation is discussed, and the solution methods are illustrated by numerical examples. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013
Multigrid transfers for nonsymmetric systems based on Schur complements and Galerkin projections
Authors: Wiesner T. A. , Tuminaro R. S. , Wall W. A. , Gee M. W.
Published: June 2013

A framework is proposed for constructing algebraic multigrid transfer operators suitable for nonsymmetric positive definite linear systems. This framework follows a Schur complement perspective as this is suitable for both symmetric and nonsymmetric systems. In particular, a connection between algebraic multigrid and approximate block factorizations is explored. This connection demonstrates that the convergence rate of a two‐level model multigrid iteration is completely governed by how well the coarse discretization approximates a Schur complement operator. The new grid transfer algorithm is then based on computing a Schur complement but restricting the solution space of the corresponding grid transfers in a Galerkin‐style so that a far less expensive approximation is obtained. The final algorithm corresponds to a Richardson‐type iteration that is used to improve a simple initial prolongator or a simple initial restrictor. Numerical results are presented illustrating the performance of the resulting algebraic multigrid method on highly nonsymmetric systems. Copyright © 2013 John Wiley & Sons, Ltd.
A path towards a better characterisation of silicon thin‐film solar cells: depth profile analysis by pulsed radiofrequency glow discharge optical emission spectrometry
Authors: Sanchez Pascal , Fernández Beatriz , Menéndez Armando , Gómez David , Pereiro Rosario , Sanz‐Medel Alfredo
Published: June 2013

The analytical potential of radiofrequency pulsed glow discharge optical emission spectrometry (rf‐PGD‐OES) is investigated for quantitative depth profiling analysis of thin‐film solar cells (TFSC) based on hydrogenated amorphous silicon (a‐Si:H). This method does not require sampling at ultra‐high‐vacuum conditions, and so it facilitates higher sample throughput than do reference techniques. In this paper, the determination of compositional depth profiles of a‐Si:H TFSC was performed by resorting to a multi‐matrix calibration procedure. For this purpose, certified reference materials, as well as laboratory standards based on individual layers of doped a‐Si:H, were simultaneously employed to build the analytical calibration curves. Results show that rf‐PGD‐OES allows us to discriminate the different layers of photovoltaic devices: the front contact composed by ZnO:Al2O3 (AZO), the a‐Si:H layer (the B‐doped, intrinsic a‐Si:H and P‐doped films), the AZO/Al back contact and substrate. A good agreement with the nominal values for element concentrations (e.g. 0.4% of H, 1.5% of B and 3.7% of P) and layer thicknesses (in the range of 950 nm for the front contact and 13 nm for the P‐doped a‐Si:H layer) was obtained, demonstrating the ability of rf‐PGD‐OES for a direct, sensitive and high‐depth‐resolution analysis of photovoltaic devices. Moreover, diffusion processes between the coating layers, which could have an important influence on the final efficiency of TFSC, can be identified as well. Hence, the findings support the use of rf‐PGD‐OES as an analysis method in the development of photovoltaic thin films. Copyright © 2013 John Wiley & Sons, Ltd.
Air‐stable copper derivatives as efficient catalysts for controlled lactide polymerization: Facile synthesis and characterization of well‐defined benzotriazole phenoxide copper complexes
Authors: Li Chen‐Yu , Hsu Shi‐Jie , Lin Chin‐lung , Tsai Chen‐Yen , Wang Jun‐Han , Ko Bao‐Tsan , Lin Chia‐Her , Huang Hsi‐Ya
Published: June 2013

Air‐stable copper catalysts supported by bis‐BTP ligands (BTP = N,O‐bidentate benzotriazole phenoxide) were synthesized and structurally characterized. The reactions of Cu(OAc)2·H2O with 2.0 molar equivalents of sterically bulky 2‐(2H‐benzotriazol‐2‐yl)‐4,6‐bis(1‐methyl‐1‐phenylethyl)phenol (CMe2PhBTP‐H) and 2‐(2H‐benzotriazol‐2‐yl)‐4,6‐di‐tert‐butylphenol (t‐BuBTP‐H) in refluxing ethanol solution afforded monomeric copper complexes [(CMe2PhBTP)2Cu] (1) and [(t‐BuBTP)2Cu] (2), respectively. The four‐coordinated copper analogue [(TMClBTP)2Cu] (3) resulted from treatment of 2‐tert‐butyl‐6‐(5‐chloro‐2H‐benzotriazol‐2‐yl)‐4‐methylphenol (TMClBTP‐H) as the ligand under the same synthetic method with ligand to metal precursor ratio of 2:1, but treatment of complex 3 in acetone gave five‐coordinated monomeric complex [(TMClBTP)2Cu(Me2CO)] (4). X‐ray diffraction of single crystals indicates that Cu complex 4 assumes a distorted square pyramidal geometry, penta‐coordinated by two BTP ligands, and one Me2CO molecule. Catalysis for lactide (LA) polymerization of BTP‐containing Cu complexes in the presence of various alcohol initiators was investigated. Complex 3 initiated by 9‐anthracenemethanol catalyzes the ring‐opening polymerization effectively not only in a “living” fashion but also in an “immortal” manner, yielding polymers with the predictable molecular weights and narrow molecular weight distributions. Initiations from multifunctional alcohols were able to produce PLLAs with two‐arm linear and three‐arm star‐shaped molecular architectures. The controlled character of Cu complex 3 also enabled us to synthesize the PEG‐b‐PLLA copolymer. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 3840–3849
Calibrations for measurement of manganese and zinc in nail clippings using portable XRF
Authors: Fleming David E. B. , Gherase Mihai R. , Anthonisen Madeleine
Published: June 2013

A calibration method was developed to assess elemental concentrations in nail clippings, using a portable X‐ray fluorescence (XRF) device. Specifically, manganese and zinc were investigated in this study. Two sets of phantom nail clipping samples were prepared, one set containing manganese and one set containing zinc. In both sets, elemental concentrations in the phantom clippings were varied from 10 to 50 µg/g, in increments of 10 µg/g. Additionally, for each concentration, five distinct masses of sample were prepared ranging from 20 to 100 mg, in increments of 20 mg. XRF spectrometry was performed with the various samples using a portable X‐ray tube and detector system.

Kα characteristic X‐rays were detected for both manganese and zinc. Intensities of detection were plotted against added concentration, resulting in linear relationships for both manganese and zinc. The slopes of these calibration lines were then examined as a function of sample mass. An empirical function was fit to the slope–mass relationship and compared with those obtained previously from other elements. By using this XRF calibration approach, it is possible to estimate elemental concentrations in human nail clippings for a variety of elements of medical interest. Copyright © 2013 John Wiley & Sons, Ltd.
Synthesis, Crystal Structures, and Magnetic Properties of Two Tetrahedral MnIIMnIII3 Complexes
Authors: Yang Pei‐Pei , Zhu Li‐Li , Xu Yun , Shao Cong‐Ying
Published: June 2013

Two tetranuclear manganese complexes, [NaMnIIMn3III(μ4‐O2–)(HL)3(SCN)4] (1) and [NaMnIIMn3III(μ4‐O2–)(HL)3Cl4][NaMnIIMn3III(μ4‐O2–)(HL)3Cl3(H2O)]ClO4·3.5H2O (2) were obtained from the reaction of manganese perchlorate with a quadridentate Schiff base ligand, 3‐(2‐hydroxybenzylideneamino)propane‐1, 2‐diol (H3L) derived from condensation of 2‐hydroxybenzaldehyde with 3‐amino‐1, 2‐propanediol, as well as the coligand KSCN or NaCl under basic conditions. Single‐crystal X‐ray studies reveal that those two complexes all have a mixed‐valent tetrahedral core, which contains an apical MnII ion and three basal MnIII ions situated in the [Mn3(μ4‐O2–)]7+ equilateral triangle plane. Fitting of the magnetic susceptibility data to the theoretical χmT vs. T expression, revealed that the presence of only antiferromagnetic interactions between the central metal atoms in 1, while both antiferromagnetic and ferromagnetic interactions are present in 2.
Cobalt(II)‐Terephthalate Frameworks Containing Bis(benz­imidazole) Derivative Co‐ligands: Syntheses, Crystal Structures, Catalytic and Fluorescence Properties
Authors: Xiao Shu‐Lin , Qin Li , Ma Pei‐Juan , Cui Guang‐Hua
Published: June 2013

Two metal‐organic coordination polymers of CoII with the molecular formulae [Co(L1)(tp)(H2O)2]n (1) and [Co(L2)(tp)·H2O]n (2) [L1 = 1, 4‐bis(benzimidazole‐1‐ylmethyl)‐ benzene; L2 = 1, 1‐(1, 4‐butanediyl)bis(5, 6‐dimethylbenzimidazole); tp = terephthalate] were synthesized and characterized by single‐crystal X‐ray diffraction studies, infrared spectroscopy (IR), thermogravimetric analysis (TGA), X‐ray powder diffraction (XRPD), and elemental analysis. The structure determination of complex 1 reveals a 2D layer with (4, 4) topology, with CoII ions at the nodes connected through tp and L1 co‐ligands. Complex 2 is the first example of a four‐connected SrAl2 structure type (sra, 42638 topology) with threefold interpenetration in CoII coordination frameworks, forming by bridging L2 and tp co‐ligands. In addition, the fluorescence and catalytic performances of the complexes for the degradation of methyl orange were investigated.
Subcortical Neural Synchrony and Absolute Thresholds Predict Frequency Discrimination Independently
Authors: Marmel F. , Linley D. , Carlyon R. P. , Gockel H. E. , Hopkins K. , Plack C. J.
Published: June 2013

The neural mechanisms of pitch coding have been debated for more than a century. The two main mechanisms are coding based on the profiles of neural firing rates across auditory nerve fibers with different characteristic frequencies (place-rate coding), and coding based on the phase-locked temporal pattern of neural firing (temporal coding). Phase locking precision can be partly assessed by recording the frequency-following response (FFR), a scalp-recorded electrophysiological response that reflects synchronous activity in subcortical neurons. Although features of the FFR have been widely used as indices of pitch coding acuity, only a handful of studies have directly investigated the relation between the FFR and behavioral pitch judgments. Furthermore, the contribution of degraded neural synchrony (as indexed by the FFR) to the pitch perception impairments of older listeners and those with hearing loss is not well known. Here, the relation between the FFR and pure-tone frequency discrimination was investigated in listeners with a wide range of ages and absolute thresholds, to assess the respective contributions of subcortical neural synchrony and other age-related and hearing loss-related mechanisms to frequency discrimination performance. FFR measures of neural synchrony and absolute thresholds independently contributed to frequency discrimination performance. Age alone, i.e., once the effect of subcortical neural synchrony measures or absolute thresholds had been partialed out, did not contribute to frequency discrimination. Overall, the results suggest that frequency discrimination of pure tones may depend both on phase locking precision and on separate mechanisms affected in hearing loss.
Niemann‐Pick type C Suspicion Index tool: analyses by age and association of manifestations
Authors: Wraith James E. , Sedel Frédéric , Pineda Mercèdes , Wijburg Frits A. , Hendriksz Christian J. , Fahey Michael , Walterfang Mark , Patterson Marc C. , Chadha‐Boreham Harbajan , Kolb Stefan A.
Published: June 2013

Objective

The Suspicion Index (SI) screening tool was developed to identify patients suspected of having Niemann‐Pick disease type C (NP‐C). The SI provides a risk prediction score (RPS) based on NP‐C manifestations within and across domains (visceral, neurological, and psychiatric). The aim of these subanalyses was to further examine the discriminatory power of the SI by age and manifestation–associations by NP‐C suspicion‐level and leading manifestations.

Methods

The original retrospectively collected data were split into three patient age groups, where NP‐C‐positive cases were >16 years (n = 30), 4–16 years (n = 18), and <4 years (n = 23), and patients’ RPS were analyzed by logistic regression. Co‐occurrence of manifestations within groups of suspicion level (low, medium, high) and leading manifestations (presence/absence of ataxia, cognitive decline, psychosis, and splenomegaly) were analyzed descriptively.

Results

NP‐C‐positive cases versus controls showed strong discriminatory power of RPS. Area under the receiver operating characteristic curve was 0.964 (>16 years) and 0.981 (4–16 years) but weaker 0.562 for infants (<4 years). Patients with RPS <70 were characterized by a lack of psychiatric manifestations and low levels of neurological involvement, suggestive of a preneurological phase of the disease. In patients >4 years, prominent leading manifestation–associations were ataxia with dystonia, dysarthria/dysphagia, and cognitive decline. Psychosis was associated with dysarthria/dysphagia but also with cognitive decline and treatment‐resistant psychiatric symptoms.

Conclusions

The SI tool maintains strong discriminatory power in patients >4 years but is not as useful for infants <4 years. The SI is also informative regarding the association and co‐occurrence of manifestations in patients with NP‐C.
Bio-friction
Authors: Jin Zhongmin , Dowson Duncan
Published: June 2013

Friction studies in biological systems are reviewed, including synovial joints (cartilage, meniscus), eye, pleurae, fat pad, skin, and oral cavity as well as daily activities associated with shaving, brushing, slip, etc. Both natural systems and medical interventions in terms of diagnoses and artificial replacements are considered. Important relevant biomechanical, physiological, and anatomical factors are reviewed in conjunction with friction studies in terms of both methodologies and friction coefficients. Important underlying tribological mechanisms related to friction are briefly discussed. A unified view on the lubrication mechanism responsible for the low friction in most soft biological tissues is presented.
Improved production of membrane proteins in Escherichia coli by selective codon substitutions
Authors: Nørholm Morten H.H. , Toddo Stephen , Virkki Minttu T.I. , Light Sara , von Heijne Gunnar , Daley Daniel O.
Published: June 2013

Membrane proteins are extremely challenging to produce in sufficient quantities for biochemical and structural analysis and there is a growing demand for solutions to this problem. In this study we attempted to improve expression of two difficult‐to‐express coding sequences (araH and narK) for membrane transporters. For both coding sequences, synonymous codon substitutions in the region adjacent to the AUG start led to significant improvements in expression, whereas multi‐parameter sequence optimization of codons throughout the coding sequence failed. We conclude that coding sequences can be re‐wired for high‐level protein expression by selective engineering of the 5′ coding sequence with synonymous codons, thus circumventing the need to consider whole sequence optimization.
The impact of inventory dynamics on long‐term stock returns – An empirical investigation of U.S. manufacturing companies
Authors: Steinker Sebastian , Hoberg Kai
Published: June 2013

This paper investigates the relationship between the inventory dynamics and long‐term stock returns of a large panel of U.S. manufacturing firms over the time period from 1991 to 2010. We propose two measures of inventory dynamics: one metric to assess the fluctuations of quarterly inventories within the year and a second metric to quantify relative year‐over‐year inventory growth. Our results indicate that within‐year inventory volatility (IV) and abnormal year‐over‐year inventory growth (ABI) are associated with abnormal stock returns. Both metrics cannot be entirely explained by common risk factors. We find that firms with high IV and low ABI have the best long‐term stock returns, and that stock performance decreases monotonically with higher ABI values. Our results are robust to various control variables including size, book‐to‐market value, industry and prior performance. We therefore conclude that changes in inventory levels provide valuable insights into the risks and opportunities faced by a company.
IMPROVED UPPER BOUNDS FOR ODD MULTIPERFECT NUMBERS
Authors: CHEN YONG-GAO , TANG CUI-E
Published: June 2013

In this paper, we prove that, if $N$ is a positive odd number with $r$ distinct prime factors such that $N\mid \sigma (N)$, then $N\lt {2}^{{4}^{r} - {2}^{r} } $ and $N{\mathop{\prod }\nolimits}_{p\mid N} p\lt {2}^{{4}^{r} } $, where $\sigma (N)$ is the sum of all positive divisors of $N$. In particular, these bounds hold if $N$ is an odd perfect number.
Long-chain SFA at thesn-1, 3 positions of TAG reduce body fat deposition in C57BL/6 mice
Authors: Gouk Shiou Wah , Cheng Sit Foon , Mok Josephine Shiueh Lian , Ong Augustine Soon Hock , Chuah Cheng Hock
Published: June 2013

The present study aimed to determine the effect of positional distribution of long-chain SFA in TAG, especially at thesn-1, 3 positions, on fat deposition using the C57BL/6 mouse model. Throughout the 15 weeks of the study, mice were fed with diets fortified with palm olein (POo), chemically interesterified POo (IPOo) and soyabean oil (SOY). Mice receiving the SOY-enriched diet gained significantly higher amounts of subcutaneous fat (P= 0·011) and total fat (P= 0·013) compared with the POo group, despite similar body mass gain being recorded. During normalisation with food consumption to obtain the fat:feed ratio, mice fed with the POo-enriched diet exhibited significantly lower visceral (P= 0·044), subcutaneous (P= 0·006) and total (P= 0·003) fat:feed than those fed with the SOY-enriched diet. It is noteworthy that mice fed with the IPOo-enriched diet gained 14·3 % more fat per food consumed when compared with the POo group (P= 0·013), despite their identical total fatty acid compositions. This was mainly attributed to the higher content of long-chain SFA at thesn-1, 3 positions of TAG in POo, which results in delayed absorption after deacylation as evidenced by the higher amounts of long-chain SFA excreted in the faeces of mice fed with the POo-enriched diet. Negative correlations were found between the subcutaneous, visceral as well as total fat accretion per food consumption and the total SFA content at thesn-1, 3 positions, while no relationships were found for MUFA and PUFA. The present results show that the positional distribution of long-chain SFA exerts a more profound effect on body fat accretion than the total SFA content.