bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of Visible‐Light Irradiation of Protoporphyrin IX on the Self‐Assembly of Tubulin Heterodimers
Authors: Vall‐Sagarra Alicia , McMicken Brady , Nonell Santi , Brancaleon Lorenzo 
Published: August 2016

AbstractThe formation and the effects of laser irradiation of the complex formed by protoporphyrin IX (PPIX) and tubulin was investigated. We have used tubulin as a model protein to investigate whether docked photoactive ligands can affect the structure and function of polypeptides upon exposure to visible light. We observed that laser irradiation in the Soret band prompts bleaching of the PPIX, which is accompanied by a sharp decrease in the intensity and average fluorescence lifetime of the protein (dominated by the four tryptophan residues of the tubulin monomer). The kinetics indicate non‐trivial effects and suggest that the photosensitization of the PPIX bound to tubulin prompts structural alterations of the protein. These modifications were also observed through changes in the energy transfer between Trp residues and PPIX. The results suggest that laser irradiation produces localized partial unfolding of tubulin and that the changes prompt modification of the formation of microtubules in vitro. Measurements of singlet oxygen formation were inconclusive in determining whether the changes are prompted by reactive oxygen species or other excited state mechanisms.
Monomer Dynamics of Alzheimer Peptides and Kinetic Control of Early Aggregation in Alzheimer's Disease
Authors: Acharya Srabasti , Srivastava Kinshuk R. , Nagarajan Sureshbabu , Lapidus Lisa J. 
Published: August 2016

AbstractThe rate of reconfiguration—or intramolecular diffusion—of monomeric Alzheimer (Aβ) peptides is measured and, under conditions that aggregation is more likely, peptide diffusion slows down significantly, which allows bimolecular associations to be initiated. By using the method of Trp–Cys contact quenching, the rate of reconfiguration is observed to be about five times faster for Aβ40, which aggregates slowly, than that for Aβ42, which aggregates quickly. Furthermore, the rate of reconfiguration for Aβ42 speeds up at higher pH, which slows aggregation, and in the presence of the aggregation inhibitor curcumin. The measured reconfiguration rates are able to predict the early aggregation behavior of the Aβ peptide and provide a kinetic basis for why Aβ42 is more prone to aggregation than Aβ40, despite a difference of only two amino acids.
Oral hygiene aspects in a study of children and young adults with the congenital and childhood forms of myotonic dystrophy type 1
Authors: Mårtensson Åsa , Ekström Anne‐Berit , Engvall Monica , Sjögreen Lotta 
Published: August 2016

AbstractThe primary aim was to study the interaction between oral hygiene, oral care, saliva production, and oral motor function in individuals with myotonic dystrophy type 1 (DM1). A secondary aim was to study how oral hygiene, oral care, and saliva flow rate are affected by gender, age, and subgroup of DM1 in this study population. The study comprised 52 individuals, seven to 29 years of age, divided into two subgroups of DM1, the congenital (N = 24) and childhood‐onset forms (N = 28). A combined dental and oral motor examination was performed and the participants or caregivers answered a questionnaire with questions about general health and disabilities, medication, dental care, and oral health. Sixteen individuals with a plaque‐, gingivitis‐, or calculus‐index score of 5–6 were considered to have poor oral hygiene. There were no significant differences between subgroups (age, gender, or form of DM1) in terms of the occurrence of calculus, gingivitis, plaque, or saliva flow rate. The mean value of the unstimulated whole saliva flow rate was 0.7(±0.44) mL/min. An open mouth at rest and oral motor dysfunction were frequent findings. The majority of Swedish children and young adults with the congenital or childhood form of DM1 have fair or poor oral hygiene, with a high occurrence of plaque and gingivitis. As a group, individuals with DM1 and poor oral hygiene have a higher frequency of caries and they report less satisfaction with their oral care at home and the quality of dental care received compared with those with good oral hygiene.
Effect of Halide Composition on the Photochemical Stability of Perovskite Photovoltaic Materials
Authors: Misra Ravi K. , Ciammaruchi Laura , Aharon Sigalit , Mogilyansky Dmitry , Etgar Lioz , Visoly‐Fisher Iris , Katz Eugene A. 
Published: August 2016

AbstractThe photochemical stability of encapsulated films of mixed halide perovskites with a range of MAPb(I1−xBrx)3 (MA=methylammonium) compositions (solid solutions) was investigated under accelerated stressing using concentrated sunlight. The relevance of accelerated testing to standard operational conditions of solar cells was confirmed by comparison to degradation experiments under outdoor sunlight exposure. We found that MAPbBr3 films exhibited no degradation, while MAPbI3 and mixed halide MAPb(I1−xBrx)3 films decomposed yielding crystallization of inorganic PbI2 accompanied by degradation of the perovskite solar light absorption, with faster absorption degradation in mixed halide films. The crystal coherence length was found to correlate with the stability of the films. We postulate that the introduction of Br into the mixed halide solid solution stressed its structure and induced more structural defects and/or grain boundaries compared to pure halide perovskites, which might be responsible for the accelerated degradation. Hence, the cause for accelerated degradation may be the increased defect density rather than the chemical composition of the perovskite materials.
Potential breeding distributions of U.S. birds predicted with both short‐term variability and long‐term average climate data
Authors: Bateman Brooke L. , Pidgeon Anna M. , Radeloff Volker C. , Flather Curtis H. , VanDerWal Jeremy , Akçakaya H. Resit , Thogmartin Wayne E. , Albright Thomas P. , Vavrus Stephen J. , Heglund Patricia J. 
Published: August 2016

AbstractClimate conditions, such as temperature or precipitation, averaged over several decades strongly affect species distributions, as evidenced by experimental results and a plethora of models demonstrating statistical relations between species occurrences and long‐term climate averages. However, long‐term averages can conceal climate changes that have occurred in recent decades and may not capture actual species occurrence well because the distributions of species, especially at the edges of their range, are typically dynamic and may respond strongly to short‐term climate variability. Our goal here was to test whether bird occurrence models can be predicted by either covariates based on short‐term climate variability or on long‐term climate averages. We parameterized species distribution models (SDMs) based on either short‐term variability or long‐term average climate covariates for 320 bird species in the conterminous USA and tested whether any life‐history trait‐based guilds were particularly sensitive to short‐term conditions. Models including short‐term climate variability performed well based on their cross‐validated area‐under‐the‐curve AUC score (0.85), as did models based on long‐term climate averages (0.84). Similarly, both models performed well compared to independent presence/absence data from the North American Breeding Bird Survey (independent AUC of 0.89 and 0.90, respectively). However, models based on short‐term variability covariates more accurately classified true absences for most species (73% of true absences classified within the lowest quarter of environmental suitability vs. 68%). In addition, they have the advantage that they can reveal the dynamic relationship between species and their environment because they capture the spatial fluctuations of species potential breeding distributions. With this information, we can identify which species and guilds are sensitive to climate variability, identify sites of high conservation value where climate variability is low, and assess how species’ potential distributions may have already shifted due recent climate change. However, long‐term climate averages require less data and processing time and may be more readily available for some areas of interest. Where data on short‐term climate variability are not available, long‐term climate information is a sufficient predictor of species distributions in many cases. However, short‐term climate variability data may provide information not captured with long‐term climate data for use in SDMs.
Breeding phenology in Rana temporaria. Local variation is due to pond temperature and population size
Authors: Loman Jon 
Published: August 2016

AbstractFrog breeding phenology in temperate zones is usually compared to progress of spring temperatures at a regional scale. However, local populations may differ substantially in phenology. To understand this, local climate and other aspects must be studied. In this study, breeding phenology of the common frog, Rana temporaria, in a set of ponds in southern Sweden is analyzed. There was within year a variation of up to 3 weeks in start of breeding among local populations. Water temperature was measured in the ponds, and breeding tended to be earlier in warmer ponds (surprise!). Breeding was also earlier in ponds with a large breeding congregation. Alternative reasons for these patterns are suggested and discussed. There was a large residual variation. The common frog has a wide range of acceptable wintering sites, and I hypothesize that the particular choice by a local population may explain part of this residual variation.
Prioritizing individual genetic variants after kernel machine testing using variable selection
Authors: He Qianchuan , Cai Tianxi , Liu Yang , Zhao Ni , Harmon Quaker E. , Almli Lynn M. , Binder Elisabeth B. , Engel Stephanie M. , Ressler Kerry J. , Conneely Karen N. , Lin Xihong , Wu Michael C. 
Published: August 2016

ABSTRACTKernel machine learning methods, such as the SNP‐set kernel association test (SKAT), have been widely used to test associations between traits and genetic polymorphisms. In contrast to traditional single‐SNP analysis methods, these methods are designed to examine the joint effect of a set of related SNPs (such as a group of SNPs within a gene or a pathway) and are able to identify sets of SNPs that are associated with the trait of interest. However, as with many multi‐SNP testing approaches, kernel machine testing can draw conclusion only at the SNP‐set level, and does not directly inform on which one(s) of the identified SNP set is actually driving the associations. A recently proposed procedure, KerNel Iterative Feature Extraction (KNIFE), provides a general framework for incorporating variable selection into kernel machine methods. In this article, we focus on quantitative traits and relatively common SNPs, and adapt the KNIFE procedure to genetic association studies and propose an approach to identify driver SNPs after the application of SKAT to gene set analysis. Our approach accommodates several kernels that are widely used in SNP analysis, such as the linear kernel and the Identity by State (IBS) kernel. The proposed approach provides practically useful utilities to prioritize SNPs, and fills the gap between SNP set analysis and biological functional studies. Both simulation studies and real data application are used to demonstrate the proposed approach.
Extracting patterns of morphometry distinguishing HIV associated neurodegeneration from mild cognitive impairment via group cardinality constrained classification
Authors: Zhang Yong , Kwon Dongjin , Esmaeili‐Firidouni Pardis , Pfefferbaum Adolf , Sullivan Edith V. , Javitz Harold , Valcour Victor , Pohl Kilian M. 
Published: August 2016

AbstractHIV‐Associated Neurocognitive Disorder (HAND) is the most common constellation of cognitive dysfunctions in chronic HIV infected patients age 60 or older in the U.S. Only few published methods assist in distinguishing HAND from other forms of age‐associated cognitive decline, such as Mild Cognitive Impairment (MCI). In this report, a data‐driven, nonparameteric model to identify morphometric patterns separating HAND from MCI due to non‐HIV conditions in this older age group was proposed. This model enhanced the potential for group separation by combining a smaller, longitudinal data set containing HAND samples with a larger, public data set including MCI cases. Using cross‐validation, a linear model on healthy controls to harmonize the volumetric scores extracted from MRIs for demographic and acquisition differences between the two independent, disease‐specific data sets was trained. Next, patterns distinguishing HAND from MCI via a group sparsity constrained logistic classifier were identified. Unlike existing approaches, our classifier directly solved the underlying minimization problem by decoupling the minimization of the logistic regression function from enforcing the group sparsity constraint. The extracted patterns consisted of eight regions that distinguished HAND from MCI on a significant level while being indifferent to differences in demographics and acquisition between the two sets. Individually selecting regions through conventional morphometric group analysis resulted in a larger number of regions that were less accurate. In conclusion, simultaneously analyzing all brain regions and time points for disease specific patterns contributed to distinguishing with high accuracy HAND‐related impairment from cognitive impairment found in the HIV uninfected, MCI cohort. Hum Brain Mapp 37:4523–4538, 2016. © 2016 Wiley Periodicals, Inc.
Angular default mode network connectivity across working memory load
Authors: Vatansever D. , Manktelow A.E. , Sahakian B.J. , Menon D.K. , Stamatakis E.A. 
Published: August 2016

AbstractInitially identified during no‐task, baseline conditions, it has now been suggested that the default mode network (DMN) engages during a variety of working memory paradigms through its flexible interactions with other large‐scale brain networks. Nevertheless, its contribution to whole‐brain connectivity dynamics across increasing working memory load has not been explicitly assessed. The aim of our study was to determine which DMN hubs relate to working memory task performance during an fMRI‐based n‐back paradigm with parametric increases in difficulty. Using a voxel‐wise metric, termed the intrinsic connectivity contrast (ICC), we found that the bilateral angular gyri (core DMN hubs) displayed the greatest change in global connectivity across three levels of n‐back task load. Subsequent seed‐based functional connectivity analysis revealed that the angular DMN regions robustly interact with other large‐scale brain networks, suggesting a potential involvement in the global integration of information. Further support for this hypothesis comes from the significant correlations we found between angular gyri connectivity and reaction times to correct responses. The implication from our study is that the DMN is actively involved during the n‐back task and thus plays an important role related to working memory, with its core angular regions contributing to the changes in global brain connectivity in response to increasing environmental demands. Hum Brain Mapp 38:41–52, 2017. © 2016 Wiley Periodicals, Inc.
Fragility Fracture Incidence in Chronic Obstructive Pulmonary Disease (COPD) Patients Associates With Nanoporosity, Mineral/Matrix Ratio, and Pyridinoline Content at Actively Bone-Forming Trabecular Surfaces
Authors: Paschalis Eleftherios P , Gamsjaeger Sonja , Dempster David , Jorgetti Vanda , Borba Victoria , Boguszewski Cesar L , Klaushofer Klaus , Moreira Carolina A 
Published: August 2016

ABSTRACT

Chronic obstructive pulmonary disease (COPD) is associated with low areal bone mineral density (aBMD) by dual-energy X-ray absorptiometry (DXA) and altered microstructure by bone histomorphometry and micro-computed tomography. Nevertheless, not all COPD patients sustain fragility fractures. In the present study, we used Raman microspectroscopic analysis to determine bone compositional properties at actively forming trabecular surfaces (based on double fluorescent labels) in iliac crest biopsies from 19 postmenopausal COPD patients (aged 62.1 ± 7.3 years). Additionally, we analyzed trabecular geometrical centers, representing tissue much older than the forming surfaces. Eight of the patients had sustained fragility fractures, and 13 had received treatment with inhaled glucocorticoids. None of the patients had taken oral glucocorticoids. The monitored parameters were mineral/matrix ratio (MM), nanoporosity, and relative glycosaminoglycan (GAG), lipid, and pyridinoline contents (PYD). There were no significant differences between the glucocorticoid-treated patients and those who did not receive any. On the other hand, COPD patients sustaining fragility fractures had significantly lower nanoporosity and higher MM and PYD values compared with COPD patients without fragility fractures. To the best of our knowledge, this is the first study to discriminate between fracture and non-fracture COPD patients based on differences in the material properties of bone matrix. Given that these bone material compositional differences are evident close to the cement line (a major bone interface), they may contribute to the inferior bone toughness and coupled with the lower lumbar spine bone mineral density values result in the fragility fractures prevalent in these patients. © 2016 American Society for Bone and Mineral Research.
Hyperargininemia and renal oxidative stress: Prevention by antioxidants and NG‐nitro‐l‐arginine methyl ester
Authors: Delwing‐de Lima Daniela , Delwing‐Dal Magro Débora , Vieira Cindy Laís Pett , Grola Gislaine Maria Marestoni , Fischer Débora Adriana , de Souza Wyse Angela Terezinha 
Published: August 2016

AbstractWe investigated the in vitro and in vivo effects of arginine (Arg) on thiobarbituric acid‐reactive substances (TBA‐RS) and on the activities of catalase (CAT), glutathione peroxidase (GSH‐Px), and superoxide dismutase (SOD) in renal tissues of rats. We also studied the influence of antioxidants (α‐tocopherol plus ascorbic acid) and nitric oxide synthase inhibitor NG‐nitro‐l‐arginine methyl ester (l‐NAME) on the effects elicited by Arg. Results showed that Arg in vitro (1.5 mM) decreased SOD activity and increased the levels of TBA‐RS in the renal medulla. Acute administration of Arg [0.8 g/kg, intraperitoneal injection] decreased CAT activity, increased SOD activity and TBA‐RS levels in the renal medulla, and decreased CAT activity in the renal cortex of rats. Most results were prevented by antioxidants and/or l‐NAME. Data indicate that Arg causes an oxidative imbalance in the renal tissues studied; however, in the presence of antioxidants and l‐NAME, some of these alterations in oxidative stress were prevented.
On the Distances between Latin Squares and the Smallest Defining Set Size
Authors: Cavenagh Nicholas , Ramadurai Reshma 
Published: August 2016

AbstractIn this note, we show that for each Latin square L of order , there exists a Latin square of order n such that L and differ in at most cells. Equivalently, each Latin square of order n contains a Latin trade of size at most . We also show that the size of the smallest defining set in a Latin square is .
One step separation of Aureobasidium pullulans from β‐poly(L‐malic acid) fermentation broth by membranes technology
Authors: Cui Jiandong , Li Hongbao , Luo Jianquan , Cao Weifeng , Qiao Changsheng , Wan Yinhua 
Published: August 2016

AbstractBACKGROUNDβ‐Poly (L‐malic acid) (PMLA) can be used as a pro‐drug or for a drug‐delivery system, while the separation of PMLA producer cells of Aureobasidium pullulans from its fermentation broth is a challenge. This paper reports the separation of A. pullulans from PMLA fermentation broth by membranes technology.RESULTSThe best separation efficiency was obtained by the membrane with a molecular weight cut off of 300 kDa, an initial feed volume of 1300 mL, a volume reduction ratio (VRR) of 7.2, a cross‐flow velocity of 6 m s−1, a trans‐membrane pressure (TMP) of 0.2 MPa, and a temperature of 40°C. The average flux reached 55.97 L m−2 h−1 with a VRR of 7.2. The main fouling mechanism during the filtration of cell suspension solution was cake layer formation, while it was pore blocking for fermentation broth and cell free broth. Since the cake layer induced by cells would reject some macromolecular substances (i.e. reduce the pore blocking and enhance the fluxes), one step separation of A. pullulans with a 300 kDa membrane was better than that with centrifugation followed by membrane filtration.CONCLUSIONOne step separation of A. pullulans by membranes technology would be beneficial for PMLA bio‐refinery. © 2016 Society of Chemical Industry
Impact of clinical training on supra‐aortic duplex and transcranial doppler examination concordance
Authors: Egido Jose A. , Garcia Ana M. , del Prado‐Gonzalez Náyade , Fuentes‐Ferrer Manuel , Lopez‐Herranz Marta , Simal‐Hernández Patricia , Fernández‐Pérez Cristina 
Published: August 2016

ABSTRACTSonographic tests are observer‐dependent. With 1,527 consecutive patients, 22 trainees were assessed at baseline and after a hands‐on 1:1 program, with a pre‐examination median of 76 studies/trainee. We evaluated the required number of supervised examinations to reach a 0.80 kappa index (ki). Statistics included linear and exponential generalized estimating equation models. In the exponential model, 76 studies for carotid‐duplex and >102 for vertebral‐duplex and transcranial Doppler were needed for a 0.80 ki. “Relevant‐categories” after‐training ki was 0.80 in carotid‐duplex and transcranial Doppler but 0.60 in vertebral‐duplex. A fixed training does not guarantee a high ki. Measuring the acquired skills of every trainee would improve quality. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 44:571–579, 2016
Morphological and dynamic contrast enhanced MR imaging features for the differentiation of chordoma and giant cell tumors in the Axial Skeleton
Authors: Lang Ning , Su Min‐Ying , Xing Xiaoying , Yu Hon J. , Yuan Huishu 
Published: August 2016

PurposeTo characterize the morphological and dynamic‐contrast‐enhanced (DCE) MRI features of chordoma and giant cell tumor (GCT) of bone occurring in the axial skeleton.Materials and MethodsA total of 13 patients with chordoma and 26 patients with GCT who received conventional T1, T2, and DCE‐MRI on 3 Tesla MR scanners were retrospectively identified and analyzed. Two radiologists evaluated morphological features independently, including the lesion location, expansile bone changes, vertebral compression, presence of paraspinal soft tissue mass, fibrous septa, and the signal intensity on T1WI and T2WI. The inter‐observer agreement was evaluated by kappa test. The DCE kinetics was measured to obtain the initial area under curve (IAUC) and the wash‐out slope; also the two‐compartmental pharmacokinetic model was applied to obtain Ktrans and kep. The diagnostic accuracy was evaluated by CHAID decision tree and ROC analysis.ResultsChordomas were more likely to show soft tissue mass than GCTs (13/13 = 100% versus 15/26 = 58%; P = 0.007), as well as fibrous septa (9/13 = 69% versus 0; P < 0.001). In decision tree analysis, presence of fibrous septa and lesion location yield 31/39 = 79% accuracy. The DCE‐MRI pharmacokinetic parameters Ktrans and kep of GCTs were significantly higher than those of chordomas, 0.13 ± 0.65 versus 0.06 ± 0.04 (1/min) for Ktrans, 0.62 ± 0.22 versus 0.17 ± 0.12 (1/min) for kep, P < 0.001 for both. If using kep = 0.43/min as the cut‐off value, it achieved 100% sensitivity and 92% specificity to differentiate chordoma from GCT, with an overall accuracy of 37/39 = 95%. The IAUC was highly correlated with Ktrans (r = 0.94), and the slope was highly correlated with kep (r = 0.95).ConclusionSeveral morphological features were significantly different between chordoma and GCT, but their diagnostic performance was inferior to that of DCE‐MRI.Level of Evidence: 4J. Magn. Reson. Imaging 2017;45:1068–1075