bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structure–Activity Relationship of Formamides as Organocatalysts: The Significance of Formamide Structure and Conformation
Authors: Nguyen Dieu , Akhani Ravish K. , Sheppard Cody I. , Wiskur Sheryl L. 
Published: March 2013

AbstractThe impact of the structure and conformation of formamides as organocatalysts was investigated and reported herein as a structure–activity relationship. Selected formamides and some amides were evaluated for their ability to activate allyltrichlorosilane in the allylation of benzaldehyde. The results suggest that the reactive conformation of secondary formamides is the less‐favorable cis conformation, whereas tertiary formamides and most amides are less reactive or unreactive in the reaction. A trend is observed between the Charton value for the N‐substituent on the secondary formamides and the amount of product formed, with an increase in yield as the substituent becomes larger. This work highlights the effects of sterics and solvent polarity on the reactivity of formamides.
Palladium‐Catalyzed Formation of C=C Bonds: A Regioselective Strategy for the Synthesis of 2‐Vinylfurans by 1,2‐H Shift of Palladium–Carbene Complexes
Authors: Zhan Haiying , Lin Xiulian , Qiu Yanying , Du Zuodong , Li Peixian , Li Yongjian , Cao Hua 
Published: March 2013

AbstractA convenient method to synthesize vinylfurans through a palladium‐catalyzed cyclization/1,2‐H shift sequence under mild conditions is described. This is an efficient strategy to synthesize 2‐vinylfurans from ene–yne ketones, and the corresponding products are obtained in good yields.
Triclosan occurrence in freshwater systems in the United States (1999–2012): A meta-analysis
Authors: Perez Angela L. , De Sylor Marianna Anderle , Slocombe Andrew J. , Lew Mindy G. , Unice Ken M. , Donovan Ellen P. 
Published: March 2013

Abstract

Recently, concern has grown regarding the presence of triclosan (TCS) in waters because of its potential for causing ecological and human health effects. The authors present a statistical analysis of TCS concentrations reported between 1999 and 2012 in freshwater environments in the United States and provide a comparison with available health-based and aquatic guidance values. Data from 46 peer-reviewed and unpublished investigations from 45 states and 1 US territory were included in the meta-analysis, encompassing the following coded water types: untreated (raw wastewater), effluent (wastewater treatment plant effluent), effluent-impacted environmental, environmental, and finished drinking water (total n = 2305). Triclosan was most frequently detected in untreated waters (92% detection frequency; mean ± standard error, 11 270 ± 2925 ng/L; n = 237), but concentrations were significantly reduced in effluent waters (83% detection frequency 775 ± 311 ng/L; n = 192, α = 0.05). Triclosan concentration in effluent-impacted environmental waters (62% detection frequency; 130 ± 17 ng/L; n = 228) was not significantly reduced from effluent waters but was significantly greater than TCS in environmental waters not classified as effluent impacted (11% detection frequency; 13 ± 3 ng/L; n = 1195). In finished drinking water, TCS was largely undetected (1% detection frequency; 4 ± 2 ng/L n = 453), suggesting that for the United States, drinking water is not an appreciable source of TCS exposure. In posttreatment waters, average TCS concentrations were below part-per-billion levels. Although no US regulatory standard exists for TCS in aquatic systems, comparison of averages reported in the present study with a predicted-no-effect concentration (PNEC) of 500 ng/L showed that 5.3% of effluent-impacted environmental waters were above the PNEC for changes in algal biomass, while only 0.25% of environmental waters surpassed this value. Environ Toxicol Chem 2013;32:1479–1487. © 2013 SETAC
Chemical, mineral composition, and sensory acceptability of cocoyam‐based recipes enriched with cowpea flour
Authors: Olayiwola Ibiyemi , Folaranmi Funmi , Adebowale Abdul‐Rasaq A. , Oluseye Onabanjo , Ajoke Sanni , Wasiu Afolabi 
Published: March 2013

AbstractThe study was conducted to improve cocoyam‐based recipes (steamed cocoyam paste [ebiripo], ikokore, and fried cocoyam balls [ojojo]) using different blends of cocoyam and cowpea flours (100:0, 80:20, 70:30, 60:40, and 50:50). The proximate composition, mineral composition, and sensory qualities of the recipes were determined using standard analytical procedures. The recipes had significantly (P < 0.05) higher contents of protein, fat, crude fiber, iron, zinc, sodium, and phosphorus compared with the control recipe (100% cocoyam flour). The protein content was highest in all recipes containing 50:50 cocoyam: cowpea flour (10.79%, 10.56%, 10.36% for ojojo, ikokore, and ebiripo, respectively). However, ikokore had higher iron (2.5 mg), phosphorus (92.5 mg), and zinc (1.92 mg) contents than ebiripo and ojojo. While the 80:20 recipe for ebiripo had significantly (P < 0.05) higher flavor and overall acceptability scores compared with other recipes. In conclusion, enrichment of cocoyam‐based recipes with cowpea flour improved the proximate composition, mineral composition, and sensory acceptability of the foods.
Crossover from negative to positive shear rate dependence in granular friction
Authors: Kuwano Osamu , Ando Ryosuke , Hatano Takahiro 
Published: March 2013

AbstractThe frictional properties of granular matter are important for analyzing various phenomena in geosciences. Here, we conduct an experiment on the shear‐rate dependence of the friction coefficient, which determines the stability of granular flow. By changing the shear rate over four orders of magnitude, we find the characteristic rate at which the least friction is realized associated with the crossover from negative to positive shear rate dependence. The least friction is explained in terms of the competition between two very different physical processes, namely frictional healing and anelasticity. We determine the expression of the characteristic shear rate, which is proportional to the square root of the normal stress.
Prospective modelling of 3D hyporheic exchange based on high‐resolution topography and stream elevation
Authors: Käser Daniel H. , Binley Andrew , Krause Stefan , Heathwaite A. Louise 
Published: March 2013

AbstractRiver managers and scientists interested in hyporheic processes need adequate tools for characterizing hyporheic exchange flow (HEF) at local sites where only poor information on subsurface properties are available. This study evaluates a three‐dimensional modelling approach, on the basis of detailed surface parameterization and a simplified subsurface structure, for comparison of potential HEF characteristics at three experimental reaches at the channel‐unit scale. First, calibration is conducted to determine the best fit‐of‐heads given the model simplification, then the structure of residuals are used to evaluate the origin of the misfit, and finally, a sensitivity analysis is conducted to identify inter‐site differences in HEF. Results show that such an approach can highlight potential magnitude differences in HEF characteristics between reaches. The sensitivity analysis is successful in delineating the small area of exchange that remains under conditions of high groundwater discharge. In this case, however, the calibrated model performs poorly in representing the exchange pattern at the sediment–water interface, thus suggesting that the approach is less adequate for a deterministic simulation of observed heads. The summary statistics are in the range of similar published models, for which the reported indicator is the root mean square error on heads normalized by the head drop over the reach. We recommend, however, that modellers use a more comparable indicator, such as a measure of the residuals normalized by a measure of observed vertical head differences. Overall, when subsurface data are unavailable or sparse, a three‐dimensional groundwater model based on high‐resolution topographic data combined with a sensitivity analysis appears as a useful tool for a preliminary characterization of HEF. Copyright © 2013 John Wiley & Sons, Ltd.
Modelling discharge through artesian springs based on a high‐resolution piezometric network
Authors: Martínez‐Santos P. , Díaz‐Alcaide S. , Castaño‐Castaño S. , Hernández‐Espriú A. 
Published: March 2013

AbstractArtesian springs are localized aquifer outlets that originate when pressurized ground water is allowed to rise to the surface. Computing artesian discharge directly is often subject to practical difficulties such as restricted accessibility, abundant vegetation or slow flow rates. These circumstances call for indirect approaches to quantify flow. This paper presents a method to estimate ground water discharge through an upwelling spring by means of a three‐layer steady‐state groundwater flow model. Model inputs include on‐site measurements of vertical sediment permeability, sediment temperatures and hydraulic gradients. About 70 spring bed piezometers were used to carry out permeability tests within the spring sediments, as well as to quantify the hydraulic head at different depths below the discharge point. Sediment temperatures were measured at different depths and correlated to permeabilities in order to demonstrate the potential of temperature as a substitute for cumbersome slug tests. Results show that the spatial distribution of discharge through the spring bottom is highly heterogeneous, as sediment permeability varies by several orders of magnitude within centimetres. Sensitivity analyses imply that geostatistical interpolation is irrelevant to the results if field datasets come from a sufficiently high resolution of piezometric records. Copyright © 2013 John Wiley & Sons, Ltd.
A coupled surface resistance model to estimate crop evapotranspiration in arid region of northwest China
Authors: Li Sien , Hao Xingmei , Du Taisheng , Tong Ling , Zhang Jianhua , Kang Shaozhong 
Published: March 2013

AbstractThe Penman–Monteith (PM) model has been widely used to estimate crop evapotranspiration (ET), but it performs poorly with sparse vegetation. By combining the Jarvis canopy resistance model and the soil resistance model, we have developed a coupled surface resistance model to address this issue. Maize field and vineyard ET, measured by the eddy covariance method during 2007 and 2008, were used to test the estimations produced by the PM model combined with our coupled surface resistance model and Jarvis model, respectively. Results indicate that PM model combined with the coupled surface resistance model produces higher determination coefficient and lower root mean square error when compared with the PM–Jarvis method, either for maize field or for the sparse vineyard, on half‐hourly or daily time scales. Our study confirms that the coupled surface resistance model produces higher accuracy than the Jarvis model and provides a method to calculate resistance parameters for using the PM model to simulate the ET of sparse vegetation. Copyright © 2013 John Wiley & Sons, Ltd.
Rating curve uncertainty and change detection in discharge time series: case study with 44‐year historic data from the Nyangores River, Kenya
Authors: Juston John , Jansson Per‐Erik , Gustafsson David 
Published: March 2013

AbstractThe intersection of the developing topic of rating curve and discharge series uncertainty with the topic of hydrological change detection (e.g., in response to land cover or climatic change) has not yet been well studied. The work herein explores this intersection, with consideration of a long‐term discharge response (1964–2007) for a ~650‐km2 headwater basin of the Mara River in west Kenya, starting with stream rating and daily gauge height data. A rating model was calibrated using Bayesian methods to quantify uncertainty intervals in model parameters and predictions. There was an unknown balance of random and systemic error in rating data scatter (a scenario not likely unique to this basin), which led to an unknown balance of noise and information in the calibrated statistical error model. This had implications on testing for hydrological change. Overall, indications were that shifts in basin's discharge response were rather subtle over the 44‐year period. A null hypothesis for change using flow duration curves (FDCs) from four different 8‐year data intervals could be either accepted or rejected over much of the net flow domain depending on different applications of the statistical error model (each with precedence in the literature). The only unambiguous indication of change in FDC comparisons appeared to be a reduction in lowest baseflow in recent years (flows with >98% exceedance probability). We defined a subjective uncertainty interval based on an intermediate balance of random and systematic error in the rating model that suggested a possibility of more prevalent impacts. These results have relevance to management in the Mara basin and to future studies that might establish linkages to historic land use and climatic factors. The concern about uncertain uncertainty intervals (uncertainty2) extends beyond the Mara and is relevant to testing change where non‐random rating errors may be important and subtle responses are investigated. Copyright © 2013 John Wiley & Sons, Ltd.
Multiple Mediation of Trauma and Parenting Stress in Mothers in Home Visiting
Authors: Ammerman Robert T. , Shenk Chad E. , Teeters Angelique R. , Noll Jennie G. , Putnam Frank W. , Van Ginkel Judith B. 
Published: March 2013

ABSTRACTParenting stress is associated with poor maternal and child outcomes. Multiple contributors to parenting stress have been proposed, but disaggregation of distinct pathways has been relatively unexplored. In addition, the contribution of maternal experience of childhood trauma has been inadequately considered. Childhood trauma and parenting stress are common in mothers in home visiting programs. Understanding the relation between childhood trauma and parenting stress holds promise for improvement of home visiting approaches. This study examined the relation between childhood trauma and parenting stress, with a focus on the mediating roles of depression and social support. Participants consisted of 208 first‐time mothers enrolled in a home visiting program who were assessed at about 5 months’ postpartum. Measures of maternal childhood trauma, depression, social support, and parenting stress were administered. A multiple mediator model revealed that childhood trauma was related to parenting stress, and the relation between childhood trauma and parenting stress was separately mediated by both depression and social support. Depression and social support uniquely and distinctly accounted for the association between childhood trauma and parenting stress. Home visiting programs may improve their impact on parenting stress by augmenting or modifying strategies to more effectively address maternal depression and social support.
Properties of spinal lamina III GABAergic neurons in naïve and in neuropathic mice
Authors: Gassner M. , Leitner J. , Gruber‐Schoffnegger D. , Forsthuber L. , Sandkühler J. 
Published: March 2013

AbstractBackgroundNerve injury leads to Aβ‐fibre‐mediated mechanical allodynia that is in part due to an impaired GABAergic inhibition in the spinal cord dorsal horn. The properties and function of GABAergic neurons in spinal cord lamina III, an area where low‐threshold mechanosensitive Aβ‐fibres terminate are, however, largely unknown.MethodsWe used transgenic mice, which express enhanced green fluorescent protein (EGFP) under control of the promoter GAD67. The morphology and neurochemical characteristics of GABAergic, EGFP‐expressing neurons were characterized. We assessed active and passive membrane properties of spinal lamina III GABAergic neurons in naïve animals and animals with a chronic constriction injury (CCI) of the sciatic nerve.ResultsEGFP‐expressing neurons in lamina III were predominantly islet cells (47%), whereas non‐EGFP‐expressing neurons were largely inverted stalked cells (40%). EGFP‐expressing neurons accounted for about 25% of GABAergic neurons in lamina III. Forty‐four percent co‐expressed glycine, 10% neuronal nitric oxide synthase and 3% co‐expressed parvalbumin. We found costaining with protein kinase CβII in 42% of EGFP‐expressing neurons but no expression of protein kinase Cγ. Membrane properties and excitability of EGFP‐and non‐EGFP‐expressing neurons from naïve and neuropathic animals were indistinguishable. The most frequent firing pattern was tonic firing (naïve: 35%, neuropathic: 37%) followed by gap firing (naïve: 33%, neuropathic: 25%). Delayed, initial burst and single‐spike firing patterns made up the remainder in both groups.ConclusionA change in membrane excitability or discharge pattern of this group of lamina III GABAergic neurons is unlikely the cause for mechanical allodynia in animals with CCI.
Transforming pain medicine: Adapting to science and society
Authors: Borsook D. , Kalso E. 
Published: March 2013

AbstractThe field of chronic pain medicine is currently facing enormous challenges. The incidence of chronic pain is increasing worldwide, particularly in the developed world. As a result, chronic pain is imposing a growing burden on Western societies in terms of cost of medical care and lost productivity. This burden is exacerbated by the fact that despite research efforts and a huge expenditure on treatment for chronic pain, clinicians have no highly effective treatments or definitive diagnostic measures for patients. The lack of an objective measure for pain impedes basic research into the biological and psychological mechanisms of chronic pain and clinical research into treatment efficacy. The development of objective measurements of pain and ability to predict treatment responses in the individual patient is critical to improving pain management. Finally, pain medicine must embrace the development of a new evidence‐based therapeutic model that recognizes the highly individual nature of responsiveness to pain treatments, integrates bio‐psycho‐behavioural approaches, and requires proof of clinical effectiveness for the various treatments we offer our patients. In the long‐term these approaches will contribute to providing better diagnoses and more effective treatments to lessen the current challenges in pain medicine.
Physiotherapy and Lumbar Facet Joint Injections as a Combination Treatment for Chronic Low Back Pain. A Narrative Review of Lumbar Facet Joint Injections, Lumbar Spinal Mobilizations, Soft Tissue Massage and Lower Back Mobility Exercises
Authors: Chambers Hannah 
Published: March 2013

AbstractObjectivesThe aim of this study was to summarize the available evidence on lumbar facet joint injections and the physiotherapy treatments, land‐based lower back mobility exercise, soft tissue massage and lumbar spinal mobilizations for chronic low back pain (CLBP). The plausibility of physiotherapy and lumbar facet joint injections as a combination treatment is discussed.MethodsUsing a systematic process, an online electronic search was performed using key words utilizing all available databases and hand searching reference lists. Using a critical appraisal tool from the Critical Appraisal Skills Programme (CASP), the literature was screened to include primary research. The main aspects of the research were summarized.ResultsThe evidence for lumbar facet joint injections suggests an overall short‐term positive effect on CLBP. Land‐based lower back mobility exercise and soft tissue massage appear to have a positive effect on CLBP in the short term and possibly in the longer term. There is insufficient evidence to draw conclusions for lumbar spinal mobilizations.ConclusionThe review indicates that lumbar facet joint injections create a short period when pain is reduced. Physiotherapy treatments including land‐based lower back mobility exercise and soft tissue massage may be of benefit during this time to improve the longer‐term outcomes of patients with CLBP. It is not possible to make generalizations or firm conclusions. The current review highlights the need for further research. A randomized controlled trial is recommended to assess the impact of physiotherapy in combination with lumbar facet joint injections on CLBP. Copyright © 2013 John Wiley & Sons, Ltd. Copyright © 2013 John Wiley & Sons, Ltd.
Recent Progress (2007–2012) in Permafrost Isotope Geochemistry
Authors: Lacelle Denis , Vasil'chuk Yurij K. 
Published: March 2013

ABSTRACTThis paper reviews contributions to permafrost isotope geochemistry published between 2007 and 2012 and proposes future research directions. It focuses on: (1) the origin and age of ground ice; (2) geochemistry and water movement in the active and transient layers; and (3) geochemistry and water movement in deep permafrost. The use of isotope geochemistry to study permafrost‐related processes has grown significantly over the last few years. These processes have been elucidated by combining geochemical and isotope measurements from different components of permafrost. Such combination has yielded new insights, for example, into the water source and transfer processes that lead to the formation of ground ice, as well as groundwater movement and residence time in permafrost. Permafrost isotope geochemistry has a promising future and should provide valuable tools for the study of a rapidly changing permafrost environment. Copyright © 2013 John Wiley & Sons, Ltd.
Effect of MoO3‐doped PTCDA as buffer layer on the performance of CuPc/C60 solar cells
Authors: Guan Min , Cao Guohua , Chu Xinbo , Zhang Yang , Liu Xingfang , Zeng Yiping 
Published: March 2013

AbstractThe long‐term performance stability of organic solar cells (OSCs), as well as their high power‐conversion efficiency, is necessary for their practical use. A stable OSC with the structure of ITO/buffer/donor/acceptor/cathode is presented. A thin layer of MoO3‐doped PTCDA (molar ratio 1:1) is adopted as the buffer in CuPc/C60 organic heterojunction photovoltaic (PV) solar cells, resulting in four to five times longer lifetime. The CT complex of buffer layer plays a decisive role in improving the stability and abnormal efficiency changes.