bluuebunny/crossref_metadata_2025 huggingface dataset:
D‐ and L‐Mannose‐Containing glyco‐­Oligoamides Show Distinct Recognition Properties When Interacting with DNA
Authors: Blázquez‐Sánchez M. Teresa , Marcelo Filipa , Fernández‐Alonso María del Carmen , del Villar‐Guerra Rafael , Samadi Abdelouahid , Cañada F. Javier , Jiménez‐Barbero Jesús , Vicent Cristina
Published: August 2015

Mannose glyco‐oligoamide β‐D‐Man‐Py‐γ‐Py‐Ind (β‐D‐Man, 1) and two new glyco‐oligoamides, β‐L‐Man‐Py‐γ‐Py‐Ind (β‐L‐Man, 2) and 6‐deoxy‐β‐D‐Man‐Py‐γ‐Py‐Ind (6‐deoxy‐β‐D‐Man, 3), have been designed and synthesized to investigate the role of hydrogen‐bonding cooperative donor centres of carbohydrates in their recognition by DNA. The free‐ and bound‐state geometries were studied, as were the affinities of the D and L enantiomers of the mannose glyco‐oligoamides (1 and 2) for DNA polymers [ct‐DNA and poly(dA‐dT)2]. TR‐NOESY and DF‐STD experiments for the diastereomeric complexes formed with DNA allow the asymmetric centres of the sugar residue that are close to the inner and outer regions of the DNA minor grooves to be distinguished. A C→N hairpin folding in β‐L‐Man derivative 2 was observed, with the α face of the sugar close to the indole ring. The C‐2 and C‐3 centres are orientated towards the inner region of the DNA minor groove. The affinity data for poly(dA‐dT)2 indicate that there is a chiral discrimination process, with β‐L‐Man derivative 2 being the best ligand. 6‐Deoxy‐β‐D‐Man derivative 3 forms the least stable complexes with DNA. Molecular dynamics simulations of β‐L‐Man derivative 2 in complex with a double‐strand dodecamer d(AT)12 are in agreement with the experimental NMR spectroscopic data. Thus, the cooperative donor centre 2‐OH in the L‐mannose enantiomer is a key contributor to the stability of the 2·poly(dA‐dT)2 complex.
Prejudice in person memory: Self‐threat biases memories of stigmatized group members
Authors: Pica Gennaro , Bélanger Jocelyn J. , Pantaleo Giuseppe , Pierro Antonio , Kruglanski Arie W.
Published: August 2015

The present research investigated whether self‐threat biases memory via retrieval‐induced forgetting. Results show that people under self‐threat whose goal is to restore their self‐worth by making prejudicial judgments that deprecate others are more likely to exhibit an enhanced RIF effect for positive items and a reduced RIF for negative items ascribed to a stereotyped target (i.e., homosexual). Overall, the present findings are consistent with the view that motivation can affect the magnitude of RIF effects in person memory and that, in turn, they can serve as mechanisms for justifying desired conclusions.
Sequence Kernel Association Analysis of Rare Variant Set Based on the Marginal Regression Model for Binary Traits
Authors: Wu Baolin , Pankow James S. , Guan Weihua
Published: August 2015

Recent sequencing efforts have focused on exploring the influence of rare variants on the complex diseases. Gene level based tests by aggregating information across rare variants within a gene have become attractive to enrich the rare variant association signal. Among them, the sequence kernel association test (SKAT) has proved to be a very powerful method for jointly testing multiple rare variants within a gene. In this article, we explore an alternative SKAT. We propose to use the univariate likelihood ratio statistics from the marginal model for individual variants as input into the kernel association test. We show how to compute its significance P‐value efficiently based on the asymptotic chi‐square mixture distribution. We demonstrate through extensive numerical studies that the proposed method has competitive performance. Its usefulness is further illustrated with application to associations between rare exonic variants and type 2 diabetes (T2D) in the Atherosclerosis Risk in Communities (ARIC) study. We identified an exome‐wide significant rare variant set in the gene ZZZ3 worthy of further investigations.
A Novel Statistic for Global Association Testing Based on Penalized Regression
Authors: Austin Erin , Shen Xiaotong , Pan Wei
Published: August 2015

Natural genetic structures like genes may contain multiple variants that work as a group to determine a biologic outcome. The effect of rare variants, mutations occurring in less than 5% of samples, is hypothesized to be explained best as groups collectively associated with a biologic function. Therefore, it is important to develop powerful association tests to identify a true association between an outcome of interest and a group of variants, in particular a group with many rare variants. In this article we first delineate a novel penalized regression‐based global test for the association between sets of variants and a disease phenotype. Next, we use Genetic Analysis Workshop 18 (GAW18) data to assess the power of the new global association test to capture a relationship between an aggregated group of variants and a simulated hypertension status. Rare variant only, common variant only, and combined variant groups are studied. The power values are compared to those obtained from eight well‐regarded global tests (Score, Sum, SSU, SSUw, UminP, aSPU, aSPUw, and sequence kernel association test (SKAT)) that do not use penalized regression and a set of tests using either the SSU or score statistics and least absolute shrinkage and selection operator penalty (LASSO) logistic regression. Association testing of rare variants with our method was the top performer when there was low linkage disequilibrium (LD) between and within causal variants. This was similarly true when simultaneously testing rare and common variants in low LD scenarios. Finally, our method was able to provide meaningful variant‐specific association information.
Organochlorine insecticides DDT and chlordane in relation to survival following breast cancer
Authors: Parada Humberto , Wolff Mary S. , Engel Lawrence S. , White Alexandra J. , Eng Sybil M. , Cleveland Rebecca J. , Khankari Nikhil K. , Teitelbaum Susan L. , Neugut Alfred I. , Gammon Marilie D.
Published: August 2015

Organochlorine insecticides have been studied extensively in relation to breast cancer incidence, and results from two meta‐analyses have been null for late‐life residues, possibly due to measurement error. Whether these compounds influence survival remains to be fully explored. We examined associations between organochlorine insecticides [p,p′‐DDT (dichlorodiphenyltrichloroethane), its primary metabolite, p,p′‐DDE, and chlordane] assessed shortly after diagnosis and survival among women with breast cancer. A population‐based sample of women diagnosed with a first primary invasive or in situ breast cancer in 1996–1997 and with available organochlorine blood measures (n = 633) were followed for vital status through 2011. After follow‐up of 5 and 15 years, we identified 55 and 189 deaths, of which 36 and 74, respectively, were breast cancer‐related. Using Cox regression models, we estimated the multivariable‐adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for lipid‐adjusted organochlorine concentrations with all‐cause and breast cancer‐specific mortality. At 5 years after diagnosis, the highest tertile of DDT concentration was associated with all‐cause (HR = 2.19; 95% CI: 1.02, 4.67) and breast cancer‐specific (HR = 2.72; 95% CI: 1.04, 7.13) mortality. At 15 years, middle tertile concentrations of DDT (HR = 1.42; 95% CI 0.99, 2.06) and chlordane (HR = 1.42; 95% CI: 0.94, 2.12) were modestly associated with all‐cause and breast cancer‐specific mortality. Third tertile DDE concentrations were inversely associated with 15‐year all‐cause mortality (HR = 0.66; 95% CI: 0.44, 0.99). This is the first population‐based study in the United States to show that DDT may adversely impact survival following breast cancer diagnosis. Further studies are warranted given the high breast cancer burden and the ubiquity of these chemicals.
Aryl hydrocarbon receptor knockout rats are insensitive to the pathological effects of repeated oral exposure to 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin
Authors: Harrill Joshua A. , Layko Debra , Nyska Abraham , Hukkanen Renee R. , Manno Rosa Anna , Grassetti Andrea , Lawson Marie , Martin Greg , Budinsky Robert A. , Rowlands J. Craig , Thomas Russell S.
Published: August 2015

Sustained activation of the aryl hydrocarbon receptor (AHR) is believed to be the initial key event in AHR receptor‐mediated tumorigenesis in the rat liver. The role of AHR in mediating pathological changes in the liver prior to tumor formation was investigated in a 4‐week, repeated‐dose study using adult female wild‐type (WT) and AHR knockout (AHR‐KO) rats treated with 2,3,7,8‐tetrachlorodibenzo‐p‐dioxin (TCDD). Beginning at 8 weeks of age, AHR‐KO and WT rats were dosed by oral gavage with varying concentrations of TCDD (0, 3, 22, 100, 300 and 1000 ng kg−1 day−1). Lung, liver and thymus histopathology, hematology, serum chemistry and the distribution of TCDD in liver and adipose tissue were examined. Treatment‐related increases in the severity of liver and thymus pathology were observed in WT, but not AHR‐KO rats. In the liver, these included hepatocellular hypertrophy, bile duct hyperplasia, multinucleated hepatocytes and inflammatory cell foci. A loss of cellularity in the thymic cortex and thymic atrophy was observed. Treatment‐related changes in serum chemistry parameters were also observed in WT, but not AHR‐KO rats. Finally, dose‐dependent accumulation of TCDD was observed primarily in the liver of WT rats and primarily in the adipose tissue of AHR‐KO rats. The results suggest that AHR activation is the initial key event underlying the progression of histological effects leading to liver tumorigenesis following TCDD treatment. Copyright © 2015 John Wiley & Sons, Ltd.
Sensitive periods for 17β‐estradiol exposure during immune system development in sea bass head kidney
Authors: Seemann Frauke , Knigge Thomas , Duflot Aurélie , Marie Sabine , Olivier Stéphanie , Minier Christophe , Monsinjon Tiphaine
Published: August 2015

An increasing body of evidence suggests that sex steroids play an important role in the development and regulation of vertebrate immune defense. Therefore, compounds with estrogenic activity may influence the immune system via receptor‐mediated pathways. The presence of estrogen receptors in immune cells and organs during the early stages of development may indicate that female steroid hormones are involved in the maturation of the fish immune system. This is of particular importance, as some marine fish are probably exposed to sources of exogenous estrogens while they reside in their estuarine nursery grounds. In this study, the influence of 17β‐estradiol (E2) on estrogen receptor and cytokine gene expression was assessed in juvenile sea bass (Dicentrarchus labrax) together with characterization of the head kidney leukocyte populations and corresponding phagocytic activity during organ regionalization from 98 to 239 dph. E2 exposure, beginning at 90 dph resulted in indirect and delayed modifications of interleukin 1β and estrogen receptor α gene expression, which may affect B‐lymphocyte proliferation in the sea bass head kidney. The E2 treatment of 120 dph fish led to an increase in estrogen receptor β2 and a decrease in transforming growth factor β1 gene expression, which coincided with decreased phagocytic activity of head kidney lymphocytes and monocytes/macrophages. Additionally, these changes were observed during developmental periods described as critical phases for B‐lymphocyte development in mammals. Consequently, exogenous estrogens have the potential to modify the innate immune response in juvenile sea bass and to exert detrimental effects on head kidney development. Copyright © 2015 John Wiley & Sons, Ltd.
Aromaticity, quantum multimolecular polyhedra, and quantum QSPR fundamental equation
Authors: Carbó‐Dorca Ramon
Published: August 2015

A causal relation connecting aromaticity with the current aromaticity descriptors used in the literature and compliant with a quantum mechanics theoretical background is described. © 2015 Wiley Periodicals, Inc.
Parametrization of macrolide antibiotics using the force field toolkit
Authors: Pavlova Anna , Gumbart James C
Published: August 2015

Macrolides are an important class of antibiotics that target the bacterial ribosome. Computer simulations of macrolides are limited as specific force field parameters have not been previously developed for them. Here, we determine CHARMM‐compatible force field parameters for erythromycin, azithromycin, and telithromycin, using the force field toolkit (ffTK) plugin in VMD. Because of their large size, novel approaches for parametrizing them had to be developed. Two methods for determining partial atomic charges, from interactions with TIP3P water and from the electrostatic potential, as well as several approaches for fitting the dihedral parameters were tested. The performance of the different parameter sets was evaluated by molecular dynamics simulations of the macrolides in ribosome, with a distinct improvement in maintenance of key interactions observed after refinement of the initial parameters. Based on the results of the macrolide tests, recommended procedures for parametrizing very large molecules using ffTK are given. © 2015 Wiley Periodicals, Inc.
Alternatives to Development: The Contribution of Indigenous Community Enterprises in Chiapas
Authors: Giovannini Michela
Published: August 2015

The interest in the potential role of community enterprises in sustaining self‐managed development strategies stems from the analysis of the scarce results provided by top‐down development interventions in indigenous settings. This paper reports on an ethnographic study carried out in the Mexican state of Chiapas, where 16 community enterprises managed by local indigenous communities have been analysed. The focus of the analysis was to identify the main needs of local indigenous communities and the contribution that community enterprises could give to addressing these needs. The main findings pinpoint some enabling factors for the emergence of community enterprises and some specific characteristics that explain the contribution of community enterprises in supporting alternative approaches to development, where local communities are actors of their own development processes. Copyright © 2015 John Wiley & Sons, Ltd.
Factors associated with false‐negative cardiovascular magnetic resonance perfusion studies: A Clinical evaluation of magnetic resonance imaging in coronary artery disease (CE‐MARC) substudy
Authors: Kidambi Ananth , Sourbron Steven , Maredia Neil , Motwani Manish , Brown Julia M. , Nixon Jane , Everett Colin C. , Plein Sven , Greenwood John P.
Published: August 2015

Purpose

To examine factors associated with false‐negative cardiovascular magnetic resonance (MR) perfusion studies within the large prospective Clinical Evaluation of MR imaging in Coronary artery disease (CE‐MARC) study population. Myocardial perfusion MR has excellent diagnostic accuracy to detect coronary heart disease (CHD). However, causes of false‐negative MR perfusion studies are not well understood.

Materials and Methods

CE‐MARC prospectively recruited patients with suspected CHD and mandated MR, myocardial perfusion scintigraphy, and invasive angiography. This subanalysis identified all patients with significant coronary stenosis by quantitative coronary angiography (QCA) and MR perfusion (1.5T, T1‐weighted gradient echo), using the original blinded image read. We explored patient and imaging characteristics related to false‐negative or true‐positive MR perfusion results, with reference to QCA. Multivariate regression analysis assessed the likelihood of false‐negative MR perfusion according to four characteristics: poor image quality, triple‐vessel disease, inadequate hemodynamic response to adenosine, and Duke jeopardy score (angiographic myocardium‐at‐risk score).

Results

In all, 265 (39%) patients had significant angiographic disease (mean age 62, 79% male). Thirty‐five (5%) had false‐negative and 230 (34%) true‐positive MR perfusion. Poor MR perfusion image quality, triple‐vessel disease, and inadequate hemodynamic response were similar between false‐negative and true‐positive groups (odds ratio, OR [95% confidence interval, CI]: 4.1 (0.82–21.0), P = 0.09; 1.2 (0.20–7.1), P = 0.85, and 1.6 (0.65–3.8), P = 0.31, respectively). Mean Duke jeopardy score was significantly lower in the false‐negative group (2.6 ± 1.7 vs. 5.4 ± 3.0, OR 0.34 (0.21–0.53), P < 0.0001).

Conclusion

False‐negative cardiovascular MR perfusion studies are uncommon, and more common in patients with lower angiographic myocardium‐at‐risk. In CE‐MARC, poor image quality, triple‐vessel disease, and inadequate hemodynamic response were not significantly associated with false‐negative MR perfusion. J. MAGN. RESON. IMAGING 2016;43:566–573.
Hypervalent radical formation probed by electron transfer dissociation of zwitterionic tryptophan and tryptophan‐containing dipeptides complexed with Ca2+ and 18‐crown‐6 in the gas phase
Authors: Fujihara Akimasa , Matsuo Sou , Tajiri Michiko , Wada Yoshinao , Hayakawa Shigeo
Published: August 2015

The relationship between peptide structure and electron transfer dissociation (ETD) is important for structural analysis by mass spectrometry. In the present study, the formation, structure and reactivity of the reaction intermediate in the ETD process were examined using a quadrupole ion trap mass spectrometer equipped with an electrospray ionization source. ETD product ions of zwitterionic tryptophan (Trp) and Trp‐containing dipeptides (Trp‐Gly and Gly‐Trp) were detected without reionization using non‐covalent analyte complexes with Ca2+ and 18‐crown‐6 (18C6). In the collision‐induced dissociation, NH3 loss was the main dissociation pathway, and loss related to the dissociation of the carboxyl group was not observed. This indicated that Trp and its dipeptides on Ca2+(18C6) adopted a zwitterionic structure with an NH3+ group and bonded to Ca2+(18C6) through the COO− group. Hydrogen atom loss observed in the ETD spectra indicated that intermolecular electron transfer from a molecular anion to the NH3+ group formed a hypervalent ammonium radical, R‐NH3, as a reaction intermediate, which was unstable and dissociated rapidly through N–H bond cleavage. In addition, N–Cα bond cleavage forming the z1 ion was observed in the ETD spectra of Trp‐GlyCa2+(18C6) and Gly‐TrpCa2+(18C6). This dissociation was induced by transfer of a hydrogen atom in the cluster formed via an N–H bond cleavage of the hypervalent ammonium radical and was in competition with the hydrogen atom loss. The results showed that a hypervalent radical intermediate, forming a delocalized hydrogen atom, contributes to the backbone cleavages of peptides in ETD. Copyright © 2015 John Wiley & Sons, Ltd.
A multilevel study of group‐focused and individual‐focused transformational leadership, social exchange relationships, and performance in teams
Authors: Chun Jae Uk , Cho Kyoungmin , Sosik John J.
Published: August 2015

Using matched reports from 73 team leaders and 359 of their members across 23 companies in Korea, we examined a multilevel model where group‐ and individual‐focused transformational leadership and their influence processes operate at the team and dyadic levels independently and interactively to be associated with team and member performance. Results indicated that group‐focused transformational leadership was positively associated with team performance through team member exchange (TMX), whereas individual‐focused transformational leadership positively related to team members' in‐role and extra‐role performance through leader–member exchange (LMX). TMX not only positively mediated the relationships between group‐focused transformational leadership and member performance after controlling for LMX but also positively moderated LMX–performance relationships. Moreover, the indirect effect of individual‐focused transformational leadership through LMX on member performance was contingent upon the level of TMX. Theoretical and applied implications are discussed. Copyright © 2015 John Wiley & Sons, Ltd.
Spaceflight‐induced bone loss alters failure mode and reduces bending strength in murine spinal segments
Authors: Berg‐Johansen Britta , Liebenberg Ellen C. , Li Alfred , Macias Brandon R. , Hargens Alan R. , Lotz Jeffrey C.
Published: August 2015

Intervertebral disc herniation rates are quadrupled in astronauts following spaceflight. While bending motions are main contributors to herniation, the effects of microgravity on the bending properties of spinal discs are unknown. Consequently, the goal of this study was to quantify the bending properties of tail discs from mice with or without microgravity exposure. Caudal motion segments from six mice returned from a 30‐day Bion M1 mission and eight vivarium controls were loaded to failure in four‐point bending. After testing, specimens were processed using histology to determine the location of failure, and adjacent motion segments were scanned with micro‐computed tomography (μCT) to quantify bone properties. We observed that spaceflight significantly shortened the nonlinear toe region of the force‐displacement curve by 32% and reduced the bending strength by 17%. Flight mouse spinal segments tended to fail within the growth plate and epiphyseal bone, while controls tended to fail at the disc‐vertebra junction. Spaceflight significantly reduced vertebral bone volume fraction, bone mineral density, and trabecular thickness, which may explain the tendency of flight specimens to fail within the epiphyseal bone. Together, these results indicate that vertebral bone loss during spaceflight may degrade spine bending properties and contribute to increased disc herniation risk in astronauts. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:48–57, 2016.
Voice disorders in the elderly: A national database study
Authors: Roy Nelson , Kim Jaewhan , Courey Mark , Cohen Seth M.
Published: August 2015

Objectives/Hypothesis

To determine the type, frequency, and factors associated with voice disorders in the elderly.

Study Design

Retrospective analysis of data from a large national administrative US claims database.

Methods

Elderly outpatients (>65 years old) with a laryngeal/voice disorder (LVD) diagnosis based on International Classification of Diseases, Ninth Revision, Clinical Modification codes from January 1, 2004 to December 31, 2008, seen by an otolaryngologist or primary care physician (PCP) were included. Data regarding age, gender, comorbid conditions, geographic location, employment history, and type of physician providing the diagnosis were collected, and multiple logistic regression was used to determine the influence of these factors in otolaryngologist‐determined LVD diagnoses.

Results

Of the almost 55 million individuals in the database, 60,773 unique patients (mean age = 74.9 years, standard deviation = 6.6 years, range = 65–105 years) had an encounter with a PCP or otolaryngologist and received an LVD diagnosis. The most frequent diagnoses overall were acute and chronic laryngitis, nonspecific dysphonia, and benign vocal fold lesions. PCPs more commonly diagnosed acute laryngitis, whereas otolaryngologists more commonly diagnosed nonspecific dysphonia and laryngeal changes/lesions. In the otolaryngology group, odds of nonspecific dysphonia and vocal fold paralysis/paresis diagnoses increased with advancing age, whereas benign laryngeal pathology, and acute and chronic laryngitis decreased. As compared to men, women had lower odds of paralysis/paresis and laryngeal cancer but higher odds of acute laryngitis and nonspecific dysphonia. Odds of specific LVDs also varied depending upon comorbid conditions and geographic location.

Conclusions

Age, gender, comorbid conditions, geographic location, and physician type were significantly associated with specific LVD diagnoses within the elderly.

Level of Evidence

4 Laryngoscope, 126:421–428, 2016
Initial investigation of a novel noninvasive weight loss therapy using MRI‐Guided high intensity focused ultrasound (MR‐HIFU) of visceral fat
Authors: Winter Patrick M. , Lanier Matthew , Partanen Ari , Dumoulin Charles
Published: August 2015

Purpose

MRI‐guided high intensity focused ultrasound (MR‐HIFU) allows noninvasive heating of deep tissues. Specifically targeting visceral fat deposits with MR‐HIFU could offer an effective therapy for reversing the development of obesity, diabetes, and metabolic syndrome.

Methods

Overweight rats received either MR‐HIFU of visceral fat, sham treatment, no treatment, or ex vivo temperature calibration. Conventional MR thermometry methods are not effective in fat tissue. Therefore, the T2 of fat was used to estimate heating in adipose tissue.

Results

HIFU treated rats lost 7.5% of their body weight 10 days after HIFU, compared with 1.9% weight loss in sham animals (P = 0.008) and 1.3% weight increase in untreated animals (P = 0.004). Additionally, the abdominal fat volume in treated animals decreased by 8.2 mL 7 days after treatment (P = 0.002). The T2 of fat at 1.5 Tesla increased by 3.3 ms per °C. The fat T2 was 103.3 ms before HIFU, but increased to 128.7 ms (P = 0.0005) after HIFU at 70 watts for 16 s and to 131.9 ms (P = 0.0005) after HIFU at 100 watts for 16 s.

Conclusion

These experiments demonstrate that MR‐HIFU of visceral fat could provide a safe, effective, and noninvasive weight loss therapy for combating obesity and the subsequent medical complications. Magn Reson Med 76:282–289, 2016. © 2015 Wiley Periodicals, Inc.
Fetal anemia caused by the Guadalajara variant of G6PD deficiency
Authors: Keller Caroline C. , Joosten Marieke , Middeldorp Annemieke M. , Knapen Maarten F. C. M.
Published: August 2015

What's already known about this topic?

The rare Guadalajara variant of G6PD deficiency is known for causing severe hemolytic anemia.

What does this study add?

This is the first published case of a diagnosed and treated fetal anemia, caused by the Guadalajara variant of G6PD deficiency.

It is important to note that non‐invasive fetal Doppler screening can be performed for pregnant women who are carriers of this X‐linked recessive disorder.
Integration‐by‐parts identities in FDR
Authors: Pittau Roberto
Published: August 2015

Four‐Dimensionally Regularized/Renormalized (FDR) integrals play an increasingly important role in perturbative loop calculations. Thanks to them, loop computations can be performed directly in four dimensions and with no ultraviolet counterterms. In this paper I prove that integration‐by‐parts (IBP) identities based on simple integrand differentiation can be used to find relations among multi‐loop FDR integrals. Since algorithms based on IBP are widely applied beyond one loop, this result represents a decisive step forward towards the use of the FDR approach in multi‐loop calculations.
Localized magnetic moments in a Dirac semimetal as a spin model with long‐range interactions
Authors: Kogan E. , Kaveh M.
Published: August 2015

Abstractauthoren We connect between the problem of thermodynamics of localized magnetic moments in a Dirac semimetal, the interaction with relativistic electrons leading to the effective ferromagnetic exchange between the moments, and the existing theories dealing with long‐range exchange interaction. We point out that the results of high‐temperature expansion for the free energy of a dilute ensemble of magnetic impurities in the semimetal performed by V. Cheianov et al. [Phys. Rev. B 86, 054424 (2012)] give an indication to the existence of a new disordered fixed point in such model.
New perspectives on the collective risk of extratropical cyclones
Authors: Hunter Alasdair , Stephenson David B. , Economou Theo , Holland Mark , Cook Ian
Published: August 2015

In this study, the relationship between the frequency and intensity of extratropical cyclones over the North Atlantic is investigated. A cyclone track database of extended October–March winters was obtained from the National Centers for Environmental Prediction and National Center for Atmospheric Research (NCEP–NCAR) reanalysis. A large positive correlation is found between winter cyclone counts and local sample mean vorticity over the exit region of the North Atlantic storm track in this cyclone track database. Conversely, a negative correlation is found over the Gulf Stream. Possible causes for the dependence are investigated by regressing winter cyclone counts and local sample mean vorticity on teleconnection indices with Poisson and linear models. The indices for the Scandinavian pattern, North Atlantic Oscillation and East Atlantic Pattern are able to account for most of the observed positive correlation over the North Atlantic. To consider the implications of frequency intensity dependence for the insurance industry, an aggregate risk metric was used as a proxy for the annual aggregate insured loss. Here, the aggregate risk is defined as the sum of the intensities of all events occurring within a season. Assuming independence between the frequency and intensity results in large biases in the variance and the extremes of the aggregate risk, especially over Scandinavia. Therefore including frequency intensity dependence in extratropical cyclone loss models is necessary to model the risk of extreme losses.
Comparison of Gaussian, logarithmic transform and mixed Gaussian–log‐normal distribution based 1DVAR microwave temperature–water‐vapour mixing ratio retrievals
Authors: Kliewer A. J. , Fletcher S. J. , Jones A. S. , Forsythe J. M.
Published: August 2015

The assumption of a Gaussian distribution is widely used in remote sensing retrievals and data assimilation for numerical weather prediction. Since many geophysical variables follow a log‐normal distribution rather than a Gaussian distribution, a mixed log‐normal and Gaussian distribution data assimilation scheme is implemented in the Cooperative Institute for Research in the Atmosphere (CIRA) one‐dimensional optimal estimation (C1DOE) retrieval system to model the background errors associated with the temperature as a Gaussian and those with respect to the mixing ratio as log‐normal. The new mixed distribution is compared against the traditional Gaussian configuration and a logarithmic transformation for the water‐vapour mixing ratio for two situations: (i) synthetic brightness temperatures generated from a log‐normal distribution and (ii) Advanced Microwave Sounding Unit (AMSU) observations from the month of September 2005 over the west Pacific, where a log‐normal signal for moisture had previously been detected. It is shown for Case 1 that, given a consistent a priori state for a log‐normal distribution, the log‐normal distribution based retrieval is the best at inverting the true state back. For Case 2, the final innovations are smallest for the mixed distribution scheme. The retrieval values are compared against the Microwave Surface and Precipitation Products System (MSPPS) and the log‐normal approach is consistently closer to the values compared with these other two approaches.
Single interval shortwave radiation scheme with parameterized optical saturation and spectral overlaps
Authors: Mašek J. , Geleyn J.‐F. , Brožková R. , Giot O. , Achom H. O. , Kuma P.
Published: August 2015

Spectral integration is the most time consuming part of solar radiative transfer codes used in numerical weather prediction. Routinely used approaches usually incline to one of two extremes – expensive and very accurate correlated k‐distribution method made affordable by doing radiative transfer calculations with reduced temporal and/or spatial resolution, or cheaper but less accurate broadband approach affordable at every grid‐point and time‐step. Both approaches have their pros and cons, but hybrid solutions do not seem very promising. The presented work improves accuracy of full spectrum broadband approach by parameterizing secondary saturation of gaseous absorption, optical saturation of Rayleigh scattering and of cloud absorption as well as non‐random gas‐cloud spectral overlap. In order to isolate the problem of spectral integration from other approximations, one builds a narrowband reference using the same delta‐two stream framework as the broadband scheme. Using this reference reveals the surprising fact that saturation effect of cloud absorption for one single layer and for the whole solar spectrum can be parameterized in a rather compact way, with one simple formula for liquid clouds and one for ice clouds. One then introduces the concept of effective cloud optical depth, which extends the applicability of parameterized cloud optical saturation to multi‐layer cases, accommodating also effects of gas‐cloud spectral overlap in the near‐infrared. A scheme with all the above parameterizations indeed pushes accuracy limits of broadband approach to the level where a single shortwave interval can be used. This opens the possibility to reduce costs by using selective intermittency, where slowly evolving gaseous transmissions are updated on the timescale of hours, while quickly varying cloud optical properties are recomputed at every model time‐step. In a companion article it will be demonstrated that the above core strategy is applicable also to thermal radiative transfer, with perhaps even better cost effectiveness there.
Dynamic path analysis – a useful tool to investigate mediation processes in clinical survival trials
Authors: Strohmaier Susanne , Røysland Kjetil , Hoff Rune , Borgan Ørnulf , Pedersen Terje R. , Aalen Odd O.
Published: August 2015

When it comes to clinical survival trials, regulatory restrictions usually require the application of methods that solely utilize baseline covariates and the intention‐to‐treat principle. Thereby, much potentially useful information is lost, as collection of time‐to‐event data often goes hand in hand with collection of information on biomarkers and other internal time‐dependent covariates. However, there are tools to incorporate information from repeated measurements in a useful manner that can help to shed more light on the underlying treatment mechanisms. We consider dynamic path analysis, a model for mediation analysis in the presence of a time‐to‐event outcome and time‐dependent covariates to investigate direct and indirect effects in a study of different lipid‐lowering treatments in patients with previous myocardial infarctions. Further, we address the question whether survival in itself may produce associations between the treatment and the mediator in dynamic path analysis and give an argument that because of linearity of the assumed additive hazard model, this is not the case. We further elaborate on our view that, when studying mediation, we are actually dealing with underlying processes rather than single variables measured only once during the study period. This becomes apparent in results from various models applied to the study of lipid‐lowering treatments as well as our additionally conducted simulation study, where we clearly observe that discarding information on repeated measurements can lead to potentially erroneous conclusions. Copyright © 2015 John Wiley & Sons, Ltd.
Inference on cancer screening exam accuracy using population‐level administrative data
Authors: Jiang H. , Brown P. E. , Walter S.D.
Published: August 2015

This paper develops a model for cancer screening and cancer incidence data, accommodating the partially unobserved disease status, clustered data structures, general covariate effects, and dependence between exams. The true unobserved cancer and detection status of screening participants are treated as latent variables, and a Markov Chain Monte Carlo algorithm is used to estimate the Bayesian posterior distributions of the diagnostic error rates and disease prevalence. We show how the Bayesian approach can be used to draw inferences about screening exam properties and disease prevalence while allowing for the possibility of conditional dependence between two exams. The techniques are applied to the estimation of the diagnostic accuracy of mammography and clinical breast examination using data from the Ontario Breast Screening Program in Canada. Copyright © 2015 John Wiley & Sons, Ltd.
Terminating observation within matched pairs of subjects in a matched cohort analysis: a Monte Carlo simulation study
Authors: Sutradhar Rinku , Baxter Nancy N. , Austin Peter C.
Published: August 2015

Matched cohort analyses are becoming increasingly popular for estimating treatment effects in observational studies. However, in the applied biomedical literature, analysts and authors are inconsistent regarding whether to terminate follow‐up among members of a matched set once one member is no longer under observation. This paper focused on time‐to‐event outcomes and used Monte Carlo simulation methods to determine the optimal approach. We found that the bias of the estimated treatment effect estimate was negligible under both approaches and that the percentage of censoring had no discernible effect on the magnitude of bias. The mean model‐based standard error of the treatment estimate was consistently higher when we terminated observation within matched pairs. Furthermore, the type 1 error rate was consistently lower when we did not terminate follow‐up within matched pairs. In conclusion, when the focus was on time‐to‐event outcomes, we demonstrated that there was no advantage to terminating follow‐up within matched pairs. Continuing follow‐up on each subject until their observation was naturally complete was superior compared with terminating a subject's observation time once its matched pair had ceased to be under observation. Given the frequency with which these analyses are conducted in the applied literature, our results provide important guidance to analysts and applied researchers as to the preferred analytic approach. Copyright © 2015 John Wiley & Sons, Ltd.
The limits of multiplexing
Authors: Shen Dan , Dittmer D. P. , Marron J. S.
Published: August 2015

We were motivated by three novel technologies, which exemplify a new design paradigm in high throughput genomics: nanostring TM, DNA‐mediated Annealing, Selection, extension, and Ligation DASL TM, and multiplex real‐time quantitative polymerase chain reaction (QPCR). All three are solution hybridization based, and all three employ on 10–1000 DNA sequence probes in a small volume, each probe specific for a particular sequence in a different human gene. nanostring TM uses 50‐mer, DASL and multiplex QPCR use ∼20‐mer probes. Assuming a 1‐nM probe concentration in a 1 μL volume, there are 10− 9 × 10− 9 × 6.23 × 1023 or 6.23 × 105 molecules of each probe present in the reaction compared to 10–1000 target molecules. Excess probe drives the sensitivity of the reaction. We are interested in the limits of multiplexing, i.e., the probability that in such a design a particular probe would bind to any other, sequence‐related probe rather than the intended, specific target. If this were to happen with appreciable frequency, this would result in much reduced sensitivity and potential failure of this design. We established upper and lower bounds for the probability that in a multiplex assay at least one probe would bind to another sequence‐related probe rather than its cognate target. These bounds are reassuring, because for reasonable degrees of multiplexing (103 probes) the probability for such an event is practically negligible. As the degree of multiplexing increases to ∼106 probes, our theoretical boundaries gain practical importance and establish a principal upper limit for the use of highly multiplexed solution‐based assays vis‐‐a‐vis solid‐support anchored designs. WIREs Comput Stat 2015, 7:394–399. doi: 10.1002/wics.1364

This article is categorized under:

Applications of Computational Statistics > Genomics/Proteomics/Genetics

Data: Types and Structure > Microarrays
Connecting Collegiate Recreation and Athletics to Leadership
Authors: McFadden Cara W. , Stenta Donald A.
Published: August 2015

Collegiate recreation and intercollegiate athletics have an impact on individual, group, and community development of students who are participants, employees, and athletes and learn leadership within these environments. This chapter explores and applies leadership frameworks in recreation and athletics.
Trinuclear Complexes of Nickel(II) and 4‐Amino‐1,2,4‐triazole
Authors: Bräunlich Irene , Medvedev Michael , Dshemuchadse Julia , Wörle Michael , Caseri Walter
Published: August 2015

Nickel(II) tetrafluoroborate is capable of forming a variety of complexes with 4‐amino‐1,2,4‐triazole (NH2trz), as NH2trz can coordinate to one, two, or three Ni2+ ions and thus can give rise in particular to polynuclear compounds of “infinite” dimensions. From rather concentrated solutions in the presence of an excess of Ni2+, however, crystallization of the trinuclear compound [Ni3(NH2trz)6(H2O)6](BF4)6·4H2O is observed. In this complex, adjacent nickel ions are connected with three bridging NH2trz ligands, and three water molecules are bound to each of the terminal nickel atoms. The Ni–N distances at the central Ni2+ ion were found to exceed those at the terminal Ni2+ ions, in account with the trans influence of the involved ligands. The distances between the nickel atoms (3.72–3.73 Å) are too large to enable considerable Ni–Ni bonds. Remarkably, over longer periods hydrolyzed BF4– reacted with the glass vessel, in which the synthesis was conducted, to yield SiF62– ions. In the resulting mixture, a BF4–/SiF62– complex developed reproducibly, of the structure [Ni3(NH2trz)6(H2O)6](BF4)4(SiF6)·4H2O. Although both the BF4– and the BF4–/SiF62– complexes are characterized by trinuclear units and exhibit similar Ni–N and Ni–O bond lengths as well as Ni–Ni distances, in the BF4– crystal there are two symmetrically inequivalent trinuclear units, while in the BF4–/SiF62– crystal the two Ni–Ni subunits in a trinuclear unit differ from each other, in particular with respect to the angles between mean planes of the triazole molecules.
Widespread intra-specific genetic homogeneity of coastal Antarctic benthic foraminifera
Authors: Majewski Wojciech , Bowser Samuel S. , Pawlowski Jan
Published: August 2015

Benthic foraminifera are a major component of the Antarctic biota. Coastal foraminiferal morphospecies are widely distributed in Antarctic waters. The question is whether these morphotypes are genetically identical or, rather, they represent a cohort of cryptic species. Here, we compared genetically nine benthic foraminiferal morphospecies from Admiralty Bay (South Shetlands) and the western Ross Sea (McMurdo Sound, Terra Nova Bay), separated by a distance of ~4500 km. Additionally, for three of these morphospecies, we included specimens from Rothera (Marguerite Bay), which is located between the two main areas of interest. Our study, based on SSU and ITS rDNA sequence data, shows that all examined morphospecies share the same genotypes despite the presence of considerable intra-individual genetic variability.
Rheological Properties of Wormlike Micelles Formed in Aqueous Systems of 3‐Alkoxy‐2‐hydroxypropyl Trimethyl Ammonium Bromides in the Presence of Sodium Octanoate
Authors: Ping Ali , Geng Peipei , Wei Xilian , Liu Jie , Zhang Junhong , Sun Dezhi , Guo Xiaodong , Yang Min
Published: August 2015

The rheological properties of aqueous systems composed of each of the four homologous cationic surfactants (3‐alkoxy‐2‐hydroxypropyl trimethyl ammonium bromides, CnHTAB, n = 12, 14, 16 and 18) in the presence of an anionic surfactant, sodium octanoate (SO), have been studied by using steady state and frequency sweep rheological measurements. The effects of surfactant concentration, hydrophobic chain length and temperature were investigated. In C14HTAB solution, the viscosity shows shear thinning in the concentration range of CC14HTAB >320 mmol/kg. Addition of SO promotes the micellar growth and results in the generation of wormlike micelles. Zero‐shear viscosity (η0) of the binary surfactant system exhibits a maximum point in the investigated concentration range, suggesting the interaction between C14HTAB and SO molecules is strongest at the optimal ratio of C14HTAB with SO. The decrease in viscosity was attributed to be the transition from entangled wormlike micelles to branching micelles after the maximum point, cryo‐TEM images revealed the changes in the structure of the wormlike micelles.
Vertical scapular osteotomy in congenital high scapula
Authors: Abdelaziz Tarek Hassan , Samir Shady
Published: August 2015

Purpose

Children with congenital high scapula (CHS) have a cosmetic and functional problem due to limited shoulder abduction. Treatment options include excision of the prominent superior angle, scapular relocation procedures and subtotal scapulectomy. Excision of the superomedial angle results only in cosmetic improvement. Subtotal scapulectomy and relocation procedures are associated with ugly scars, extensive bleeding and high incidence of brachial plexus injuries. Vertical scapular osteotomy (VSO) is another surgical option that provides cosmetic and functional improvement. The aim of this study is to assess medium to long term results of VSO in treatment of CHS.

Methods

This is a prospective case series study. Seven children with CHS were treated at our unit. Age ranged from 5–13 years with an average of 8.4 years. All children were females with unilateral affection. All children underwent a VSO as described by Campbell. We used the Cavendish grading system together with combined shoulder abduction for assessment. Follow up averaged 4.6 years.

Results

All children and parents were extremely satisfied with the results of surgery. All patients experienced an improvement in global shoulder abduction with an average gain in abduction of 52.9°. All patients experienced an improvement in cosmetic appearance with better shoulder levelling. The Cavendish grade improved in all patients.

Conclusion

This study emphasizes the results of previous authors demonstrating that CHS can be treated successfully with a VSO. The procedure is simple and its results are reproducible.
Mice doubly‐deficient in the Arf GAPs SMAP1 and SMAP2 exhibit embryonic lethality
Authors: Sumiyoshi Mami , Masuda Narumi , Tanuma Nobuhiro , Ogoh Honami , Imai Eri , Otsuka Mizuki , Hayakawa Natsuki , Ohno Kinuyo , Matsui Yasuhisa , Hara Kanae , Gotoh Risa , Suzuki Mai , Rai Shinya , Tanaka Hirokazu , Matsumura Itaru , Shima Hiroshi , Watanabe Toshio
Published: August 2015

In mammals, the small Arf GTPase‐activating protein (SMAP) subfamily of Arf GTPase‐activating proteins consists of closely related members, SMAP1 and SMAP2. These factors reportedly exert distinct functions in membrane trafficking, as manifested by different phenotypes seen in single knockout mice. The present study investigated whether SMAP proteins interact genetically. We report for the first time that simultaneous loss ofSMAP1 andSMAP2 promotes apoptosis in the distal region of E7.5 mouse embryos, likely resulting in embryonic lethality. Thus, at least oneSMAP gene, eitherSMAP1 orSMAP2, is required for proper embryogenesis.
Chromatin, DNA structure and alternative splicing
Authors: Nieto Moreno Nicolás , Giono Luciana E. , Cambindo Botto Adrián E. , Muñoz Manuel J. , Kornblihtt Alberto R.
Published: August 2015

Coupling of transcription and alternative splicing via regulation of the transcriptional elongation rate is a well‐studied phenomenon. Template features that act as roadblocks for the progression of RNA polymerase II comprise histone modifications and variants, DNA‐interacting proteins and chromatin compaction. These may affect alternative splicing decisions by inducing pauses or decreasing elongation rate that change the time‐window for splicing regulatory sequences to be recognized. Herein we discuss the evidence supporting the influence of template structural modifications on transcription and splicing, and provide insights about possible roles of non‐B DNA conformations on the regulation of alternative splicing.