bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct Growth of CoFe2 Alloy Strongly Coupling and Oxygen‐Vacancy‐Rich CoFe2O4 Porous Hollow Nanofibers: an Efficient Electrocatalyst for Oxygen Evolution Reaction
Authors: Wu Liang , Shi Lei , Zhou Shiming , Zhao Jiyin , Miao Xianbing , Guo Jianhui 
Published: June 2018

AbstractEfficient electrocatalysts for the oxygen evolution reaction (OER) is crucial for improving the performance of metal−air batteries and water splitting. In this study, the CoFe2 alloy strongly coupling and oxygen‐vacancy‐rich CoFe2O4 (CoFe2 alloys/CoFe2O4) porous hollow complex nanofibers, as a highly efficient and stable electrocatalyst for OER, have been synthesized via a facile method of electrospinning combining with two‐step heat treatment. The obtained CoFe2 alloys/CoFe2O4 porous hollow complex nanofibers show high electrical conductivity with the smaller charge transfer resistance than that of the commercial RuO2, and even two orders of magnitude lower than that of the single CoFe2O4 porous hollow nanofibers. When used as an electrocatalyst for OER, it demonstrates a superior electrochemical performance with an over‐potential of 300 mV at the current density of 10 mA cm−2, which is comparable to that of the commercial RuO2 but obviously better than that of the single CoFe2O4 porous hollow nanofibers. Moreover, the CoFe2 alloys/CoFe2O4 porous hollow complex nanofibers exhibit remarkably stability with negligible potential increase of only 1.2 % at high current density of 100 mA cm−2 for 16 h. Meanwhile, the CoFe2 alloys/CoFe2O4 porous hollow complex nanofibers also show an excellent hydrogen evolution reaction (HER) activity, affording an over‐potential of 152 mV at the current density of 10 mA cm−2. When using for water splitting in 1 M KOH, the CoFe2 alloys/CoFe2O4 porous hollow complex nanofibers delivers a current density of 10 mA cm−2 at a cell voltage of 1.687 V. More important, the direct growth of CoFe2 alloys on the CoFe2O4 base of the porous hollow nanofibers can be an effective way to control the coupling of the CoFe2 alloys and CoFe2O4, the electronic conductivity and the active sites, and then the electrochemical performance of OER.
Transport of perfluorocarbon tracers in the Cranfield Geological Carbon Sequestration Project
Authors: Soltanian Mohamad Reza , Amooie Mohammad Amin , Cole David , Graham David , Pfiffner Susan , Phelps Tommy , Moortgat Joachim 
Published: June 2018

AbstractA field‐scale carbon dioxide (CO2) injection pilot project was conducted by the Southeast Regional Carbon Sequestration Partnership (SECARB) at Cranfield, Mississippi. Two associated campaigns in 2009 and 2010 were carried out to co‐inject perfluorocarbon tracers (PFTs) and sulfur hexafluoride (SF6) with CO2. Tracers in gas samples from two observation wells were analyzed to construct breakthrough curves. In this work, we present the field data and numerical modeling of the flow and transport of CO2, brine, and tracers. A high‐resolution static model of the formation geology in the detailed area study (DAS) was used to capture the impact of connected flow pathways created by fluvial channels on breakthrough curves and breakthrough times of PFTs and SF6 tracers. We use the cubic‐plus‐association (CPA) equation of state, which takes into account the polar nature of water molecules, to describe the phase behavior of CO2–brine‐tracer mixtures. Our simulated results show good agreement for the 2009 tracer campaign in Cranfield, while a larger discrepancy emerges by 2010. The combination of multiple tracer injection pulses with detailed numerical simulations proves to be a powerful tool in constraining both formation properties and how complex flow paths develop over time. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd.
Association of antidiabetic medication use, cognitive decline, and risk of cognitive impairment in older people with type 2 diabetes: Results from the population‐based Mayo Clinic Study of Aging
Authors: Wennberg Alexandra M.V. , Hagen Clinton E. , Edwards Kelly , Roberts Rosebud O. , Machulda Mary M. , Knopman David S. , Petersen Ronald C. , Mielke Michelle M. 
Published: June 2018

ObjectiveTo determine the cross‐sectional and longitudinal associations between diabetes treatment type and cognitive outcomes among type II diabetics.MethodsWe examined the association between metformin use, as compared to other diabetic treatment (ie, insulin, other oral medications, and diet/exercise) and cognitive test performance and mild cognitive impairment (MCI) diagnosis among 508 cognitively unimpaired at baseline type II diabetics enrolled in the Mayo Clinic Study of Aging. We created propensity scores to adjust for treatment effects. We used multivariate linear and logistic regression models to investigate the cross‐sectional association between treatment type and cognitive test z scores, respectively. Mixed effects models and competing risk regression models were used to determine the longitudinal association between treatment type and change in cognitive test z scores and risk of developing incident MCI.ResultsIn linear regression analyses adjusted for age, sex, education, body mass index, APOE ε4, insulin treatment, medical comorbidities, number of medications, duration of diabetes, and propensity score, we did not observe an association between metformin use and cognitive test performance. Additionally, we did not observe an association between metformin use and cognitive test performance over time (median = 3.7‐year follow‐up). Metformin was associated with an increased risk of MCI (subhazard ratio (SHR) = 2.75; 95% CI = 1.64, 4.63, P < .001). Similarly, other oral medications (SHR = 1.96; 95% CI = 1.19, 3.25; P = .009) and insulin (SHR = 3.17; 95% CI = 1.27, 7.92; P = .014) use were also associated with risk of MCI diagnosis.ConclusionsThese findings suggest that metformin use, as compared to management of diabetes with other treatments, is not associated with cognitive test performance. However, metformin was associated with incident MCI diagnosis.
New Method for Synthesis of Multi‐substituted Imidazoles
Authors: Marzouk Adel A. , Mohamed Shaaban K. , Aljohani Enas T. , Abdelhamid Antar A. 
Published: June 2018

Here, we reported two methods for the synthesis of multi‐substituted imidazoles, firstly via four‐component cyclocondensation reaction of benzil, aliphatic amines (allylamine or pentylamine), and aromatic aldehyde and ammonium acetate. Using an ionic liquid catalyst namely, diethyl ammonium hydrogen sulfate, and under solvent‐free conditions. Secondly, via the alkylation of synthesized NH imidazoles with alkyl halide (allyl bromide and pentyl bromide) gave 8a–c in high yield (average 90%), the products can be purified by a non‐chromatographic method, and these newly synthesized compounds have been characterized by spectral data: FTIR, IR, 1H, 13C nuclear magnetic resonance, the elemental analysis, and the X‐ray structure.
A variation of pigmentation in the glabrous skin of dogs
Authors: Elofsson Rolf , Kröger Ronald H. H. 
Published: June 2018

AbstractThe usual pigmentation pattern in mammalian skin consists of fixed melanocytes in the basal layer of the epidermis, supplying keratinocytes with melanosomes. We observed that the glabrous skin (rhinaria and footpads) of dogs deviates from this pattern. In dogs, melanocytes are found in both the dermis and epidermis. The epidermal melanocytes are situated in the intercellular spaces of the basal and spinous layers. They are characterized by a quantity of cytoplasm containing a centriole, also developing melanosomes, and in some cases annulate lamellae. There is a high frequency of closely apposed melanocytes in the epidermis. Melanosomes in different stages of formation are also abundant. The morphology of the glabrous skin of dogs suggests transport of melanocytes from the dermis into the epidermis and formation of melanosomes in the epidermis. A distributed and intense pigment formation may be necessary to achieve the black noses of many dog breeds and wild canids, as well as dark footpads despite heavy abrasion and rapid skin renewal.
Discovery of biomarkers to identify peri‐implant osteolysis before radiographic diagnosis
Authors: Ross Ryan D. , Deng Youping , Fang Rui , Frisch Nicholas B. , Jacobs Joshua J. , Sumner Dale R. 
Published: June 2018

ABSTRACTPeri‐implant osteolysis is commonly diagnosed after substantial bone loss has occurred, making revision surgery more challenging. The goal of the current study was to identify urinary biomarkers that differentiate total hip replacement patients who eventually develop osteolysis from patients who do not. We used a repository of 24‐h urine samples collected prior to surgery and annually thereafter in 26 patients, 16 who developed osteolysis, and 10 who did not. We examined the markers at radiographic diagnosis, annually for 6 years preceding diagnosis, at the first post‐operative sampling point, and pre‐operatively. Patients in the osteolysis and non‐osteolysis groups were matched according to time post‐surgery and did not differ in the male:female ratio or age at surgery. Seven candidate biomarkers were measured, including free deoxypyridinoline (DPD), cross‐linked N‐telopeptides (NTX), interleukin‐6 (IL‐6), interleukin‐8 (IL‐8), osteoprotegerin (OPG), α‐crosslaps (α‐CTX), and β‐crosslaps (β‐CTX). As an individual biomarker, DPD demonstrated the highest ability to predict osteolysis, with an area under the curve (AUC) in Receiver Operating Characteristic (ROC) analyses of 0.844 at 6 years prior to diagnosis. A panel of α‐CTX and IL‐6 was able to identify at‐risk patients with an AUC of 0.941 or greater at all post‐operative time points and an AUC of 1.000 pre‐operatively. The results demonstrate the potential of using non‐invasive biomarkers to identify patients at risk for peri‐implant osteolysis long before the emergence of radiographic signs. Further, the high accuracy of the pre‐operative biomarker levels demonstrates the potential importance of pre‐existing, patient‐specific factors driving subsequent osteolysis. Study Design © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:2754–2761, 2018.
Immunohistopathologic evaluation of Drynaria fortunei rhizome extract in the management of Class II furcation defects in a canine model
Authors: Afifi Marwa M. , Kotry Gehan S. , El‐Kimary Gillan I. , Youssef Hayat A. 
Published: June 2018

AbstractBackgroundManagement of furcation defects is still a challenging subject in periodontal therapy. Drynaria fortunei (Df) is a common type of traditional Chinese herb in the area of orthopedics and traumatology. In vitro and tissue engineering studies have shown that Df induces osteoblastic proliferation and promotes the differentiation of human periodontal ligament cells. This study investigated the management of Class II furcation defects in dogs using guided tissue regeneration (GTR) and Df granules mixed with β‐tricalcium phosphate (β‐ TCP) alloplast.MethodsSixteen Class II critical‐sized furcation defects were surgically created in four mongrel dogs: Eight defects were treated with GTR and Df granules mixed with (β‐TCP) alloplast served as the experimental group, while the other eight were managed with GTR and alloplast, served as control. Dogs were sacrificed at 4 and 8 weeks and the premolars were processed for the evaluation of treatment outcome including; osteoblastic count (OC), cementum layer thickness (CLT), percentage of collagen in bone matrix (CBM), and alkaline phosphatase (ALP) immunoreaction.ResultsExperimental group treated with Df showed a significant increase (P < 0.001) in the values of OC, CLT, CBM, and ALP immunoreactivity when compared with control at 4 and 8 weeks after treatment.ConclusionDrynaria fortunei demonstrated increased regeneration and bone formation when used in the treatment of furcation defects in a canine model.
Simultaneous derivatization and lighter‐than‐water air‐assisted liquid–liquid microextraction using a homemade device for the extraction and preconcentration of some parabens in different samples
Authors: Farajzadeh Mir Ali , Bakhshizadeh Aghdam Mehri , Afshar Mogaddam Mohammad Reza , Alizadeh Nabil Ali Akbar 
Published: June 2018

AbstractSimultaneous derivatization and air‐assisted liquid–liquid microextraction using an organic that is solvent lighter than water has been developed for the extraction of some parabens in different samples with the aid of a newly designed device for collecting the extractant. For this purpose, the sample solution is transferred into a glass test tube and a few microliters of acetic anhydride (as a derivatization agent) and p‐xylene (as an extraction solvent) are added to the solution. After performing the procedure, the homemade device consists of an inverse funnel with a capillary tube placed into the tube. In this step, the collected extraction solvent and a part of the aqueous solution are transferred into the device and the organic phase indwells in the capillary tube of the device. Under the optimal conditions, limits of detection and quantification for the analytes were obtained in the ranges of 0.90–2.7 and 3.0–6.1 ng/mL, respectively. The enrichment and enhancement factors were in the ranges of 370–430 and 489–660, respectively. The method precision, expressed as the relative standard deviation, was within the range of 4–6% (n = 6) and 4–9% (n = 4) for intra‐ and interday precisions, respectively. The proposed method was successfully used for the determination of methyl‐, ethyl‐, and propyl parabens in cosmetic, hygiene and food samples, and personal care products.
Monolith affinity chromatography for the rapid quantification of a single‐chain variable fragment immunotoxin
Authors: Satzer Peter , Sommer Ralf , Paulsson Johanna , Rodler Agnes , Zehetner Romana , Hofstädter Klaus , Klade Christoph , Jungbauer Alois 
Published: June 2018

AbstractWe developed a novel analytical method for concentration determination of tandem single‐chain antibody diphtheria toxin (immunotoxin). The method is based on polymethacrylate monoliths with Protein L ligands as the binding moiety. Different buffers were tested for elution of the Protein L‐bound immunotoxin and 4.5 M guanidinium hydrochloride performed best. We optimized the elution conditions and the method sequence resulting in a fast and robust method with a runtime <10 min. Fast determination of immunotoxin is critical if any process decisions rely on this data. We determined method performance and a lower limit of detection of 27 μg/mL and a lower limit of quantification of 90 μg/mL was achieved. The validity of the method in terms of residual analysis, precision, and repeatability was proven in a range from 100 to 375 μg/mL. The short runtime and ease of use of a high‐performance liquid chromatography method is especially useful for a process analytical tool approach. Bioprocesses related to immunotoxin where fermentation or other process parameters can be adjusted in accordance to the immunotoxin levels will be benefited from this method to achieve the highest possible purity and productivity.
An integrated demand and supply conceptual framework: Investigating agritourism services
Authors: Brandano Maria Giovanna , Osti Linda , Pulina Manuela 
Published: June 2018

AbstractThe present paper offers an integrated conceptual framework to jointly analyze demand and supply of agritourism firms and aims to identify motivations along with perceptions of externalities that influence the choice of a firm over another. On the supply side, a cluster analysis identifies homogenous groups of agritourism firms. On the demand side, a factor analysis is run on a set of motivations and environmental externalities and a probabilistic model estimates the determinants that influence the likelihood to choose 1 type of firm over the other. The results show that traditional and genuine food, culture, and authenticity are elements that determine the choice of 1 firm over another. A further contribution of this paper is the identification of environmental externalities as determinants of the attractiveness of a firm. From a marketing perspective, linking demand to supply is essential to determine product development strategies capable of satisfying actual and potential customers. Several strategies are proposed to different types of agritourism firms to attract and retain customers.
An experimental and theoretical study on the kinetics of the reaction between 4‐hydroxy‐3‐hexanone CH3CH2C(O)CH(OH)CH2CH3 and OH radicals
Authors: Dib Gisèle El , Aazaad Basheer , Lakshmipathi Senthilkumar , Laversin Hélène , Roth Estelle , Chakir Abdelkhaleq 
Published: June 2018

AbstractExperimental and theoretical rate coefficients are determined for the first time for the reaction of 4‐hydroxy‐3‐hexanone (CH3CH2C(O)CH(OH)CH2CH3) with OH radicals as a function of temperature. Experimental studies were carried out using two techniques. Absolute rate coefficients were measured using a cryogenically cooled cell coupled to the pulsed laser photolysis‐laser‐induced fluorescence technique with temperature and pressure ranges of 280‐365 K and 5‐80 Torr, respectively. Relative values of the studied reaction were measured under atmospheric pressure in the range of 298‐354 K by using a simulation chamber coupled to a FT‐IR spectrometer. In addition, the reaction of 4H3H with OH radicals was studied theoretically by using the density functional theory method over the range of 278‐350 K. Results show that H‐atom abstraction occurs more favorably from the C–H bound adjacent to the hydroxyl group with small barrier height. Theoretical rate coefficients are in good agreement with the experimental data. A slight negative temperature dependence was observed in both theoretical and experimental works. Overall, the results are deliberated in terms of structure–reactivity relationship and atmospheric implications.
Quantum mechanics investigation on initial decomposition of ammonia borane in glyme
Authors: Chatterjee Tanusree , Thynell Stefan T. 
Published: June 2018

AbstractThe chemical kinetics of ammonia borane (AB) in glyme solution is studied using quantum mechanics (QM) based calculations along with experimental results available in the literature. The primary objective of this study is to propose a detailed reaction mechanism that explains the formation of species observed during AB decomposition for temperatures ranging from 323 to 368 K. The quantum mechanics investigation uses transition state theory to identify the relevant reaction pathways. Intrinsic reaction coordinate calculations use the identified transition‐state structure to link the reactants to the products. These calculations were performed using the Gaussian 09 program package, including the solvation model based on density (SMD) with acetonitrile as the solvent. Thermodynamic properties of species at equilibrium or at transition states were computed using the G4(MP2) compound method. Sensitivity analysis was performed using a species conservation model to identify reactions and species that play a critical role. This study confirms the previous experimental observation regarding the initiation of decomposition of AB in glyme. It also elucidates the role of DADB, ammonium borohydride salt ([BH4]−[NH4]+) and BH2NH2 in hydrogen release and intermediates formed during initial phase of AB decomposition. This work shows how QM calculations along with experimental results can contribute to our understanding of the complex chemical kinetics involved during AB dehydrogenation.
Knowledge sharing behavior in online discussion communities: Examining behavior motivation from social and individual perspectives
Authors: Kumi Richard , Sabherwal Rajiv 
Published: June 2018

BackgroundPrior research has advanced several reasons, using various perspectives, to explain user participation in online discussion communities. Nonetheless, relatively few studies have explored personal and social factors together in the same study to explain knowledge seeking and sharing behaviors in online discussion communities; additionally, relatively few studies have examined the outcomes of these behaviors.Research questionUsing social identity and personal motivation theories, this study examines the following research questions. First, how do social identity and extrinsic and intrinsic motivations influence knowledge seeking and sharing behaviors in online discussion communities? Second, how do knowledge seeking and sharing behaviors affect satisfaction with a community?MethodologyTo address these two research questions, we collected data from 144 users from two online communities and analyze the data using seemingly unrelated regression.ResultsThe results indicate that intrinsic and extrinsic motivations have different impacts on knowledge seeking and sharing behaviors. Only one of the dimensions of social identity, affective social identity, has a significant impact on knowledge seeking and sharing behaviors.ConclusionsKnowledge sharing and seeking behaviors are not driven by the same personal motivations. We discuss practical implications on online discussion communities, including insights into motivations, behaviors, and outcomes.
Inverse problems for first‐order differential systems with periodic 2 × 2 matrix potentials and quasi‐periodic boundary conditions
Authors: Currie Sonja , Roth Thomas T. , Watson Bruce A. 
Published: June 2018

A generalisation is given of the inverse problem considered in S. Currie, B.A. Watson, and T.T. Roth. First‐order systems in
on
with periodic matrix potentials and vanishing instability intervals, Math. Meth. Appl. Sci.38 (2015), 4435‐4447. In particular, the self‐adjoint first‐order system, JY ′ + QY = λY, with integrable, real, symmetric, and π‐periodic, 2 × 2 matrix potential Q is considered, where
. It is shown that all eigenvalues to the above equation with boundary conditions Y(π) = ±R(θ)Y(0), where R(θ) is the rotation matrix
, are double eigenvalues if and only if Q = rI for some real scalar valued integrable function r.
Clinicians have several therapeutic relationships and patients only one: The effect on their assessments of relationships
Authors: Greenberg Lauren , Bremner Stephen , Carr Catherine , Priebe Stefan 
Published: June 2018

AbstractObjectivesLittle attention has been given to the common assessment problem that clinicians assess outcomes of several patients and may rate them in comparison to one another, whereas patients assess only their own outcomes without any comparison. We explored empirically whether this would lead to a greater variability of clinician ratings as compared to patient ratings.MethodsData from two independent samples in which clinicians and patients, using consistent instruments, rated their therapeutic relationships. We present descriptive statistics of variability and intracluster correlation coefficients.ResultsThe Helping Alliance Scale was completed at baseline and follow‐up by 20 clinicians and 103 patients in an observational study and by 88 clinicians and 431 patients in a trial. Patients tended to rate their relationship 5–10% more highly than their clinicians, but with 50–100% more variability. Intraclinician Helping Alliance Scale ratings were more correlated than those by patients (intracluster correlation coefficients 0.3–0.7 vs. 0.0–0.2).ConclusionContrary to our assumption, clinicians' ratings of therapeutic relationships were in both samples less variable than those of their patients. When clinicians rate outcomes of several patients, a cluster effect of ratings may have to be considered in the design and analysis.