bluuebunny/crossref_metadata_2025_split huggingface dataset:
Stereoselective Olefination and Regiospecific Vicinal Difunctionalization of Imines with α‐(Benzothiazol‐2‐ylsulfonyl) Carbonyl Compounds
Authors: Shao You‐Dong , Wu Xue‐Song , Tian Shi‐Kai 
Published: January 2012

AbstractDepending on their structures, imines are able to undergo either olefination or vicinal difunctionalization with various α‐(benzothiazol‐2‐ylsulfonyl) carbonyl compounds in the absence of external bases. The olefination reaction of aromatic imines with α‐(benzothiazol‐2‐ylsulfonyl) carbonyl compounds proceeds smoothly in tetrahydrofuran at 70 °C to give structurally diverse α,β‐unsaturated esters, amides, and ketones in good to excellent yields and with extremely high (E) selectivity. In contrast, the carbon–nitrogen double bonds of cyclic imines and the carbon–carbon double bonds of α,β‐unsaturated imines are subjected to regiospecific vicinal difunctionalization with α‐(benzothiazol‐2‐ylsulfonyl) carbonyl compounds under the same reaction conditions to give a variety of benzothiazole derivatives in good to excellent yields. It is noteworthy that the benzothiazole moiety is present in a number of antitumor agents and bioluminescent molecules. In addition, plausible reaction pathways have been proposed to account for these transformations, and these are substantially supported by ESI‐MS analysis of the reaction mixtures.
Stereocontrolled Synthesis of the cis‐Hydroxydecalin System: Towards Biologically Active 19‐nor‐Clerodanes
Authors: Mirzayans Paul Malek , Pouwer Rebecca H. , Williams Craig M. , Bernhardt Paul V. 
Published: January 2012

AbstractThe 19‐nor‐clerodanes are compact, densely functionalized diterpenes based on a stereocentre‐rich decalin scaffold. To date only a few examples of the 19‐nor‐clerodanes have been synthesized, hence new flexible strategies are required. We herein describe the stereocontrolled construction of the cis‐hydroxy decalin core in a concise fashion.
Modified Screen‐Printed Electrodes Based on Oxidized Graphene Nanoribbons for the Selective Electrochemical Detection of Several Molecules
Authors: Valentini F. , Romanazzo D. , Carbone M. , Palleschi G. 
Published: January 2012

AbstractAn electrochemical study of several molecules has been carried out, using novel graphene‐modified screen printed electrodes (GN‐SPEs). Different analytical parameters have been optimized, as: the graphene concentration for a homogeneous coating of the electrode surfaces, the scan rates and the potential window for the electrochemical detection of potassium ferricyanide, catechol, hexaammineruthenium(III) chloride, sodium hexachloroiridate‐(III) hydrate, dopamine, epinephrine, L‐tyrosine, 3,4‐dihydroxyphenylacetic acid (DOPAC), ascorbic acid, uric acid, 4‐acetamidophenol (acetaminophen), NADH, H2O2, caffeic acid, guanine, and serotonin (5‐HT) hydrochloride. In addition, different experimental conditions were tested, especially the solvents used to obtain a stable graphene nanoribbon dispersion. Among these various analytes, especially good results were obtained with NADH which was detected at an applied potential of +0.44 V, vs.Ag/AgCl, compared to the +0.55 V at pristine SWCNT paste electrodes, [7]), and with a detection limit (of 200 µM), good sensitivity (1.70 µA/mM mm2), and good reproducibility (RSD% ranging from 3 to 20 for different SPEs used for each single point of calibration plot). Also dopamine, has been successfully detected at GN‐ SPEs even in the presence of an electrochemical interfering compound. Results for dopamine showed a good detection limit (of 4 µM), sensitivity (17.70 µA/mM mm2) and reproducibility (RSD% ranging from 7 to 20 for different SPEs used for each single point of calibration plot).
Goal‐oriented space–time adaptivity in the finite element Galerkin method for the computation of nonstationary incompressible flow
Authors: Besier Michael , Rannacher Rolf 
Published: January 2012

SUMMARYThis paper presents a general strategy for designing adaptive space–time finite element discretizations of the nonstationary Navier–Stokes equations. The underlying framework is that of the dual weighted residual method for goal‐oriented a posteriori error estimation and automatic mesh adaptation. In this approach, the error in the approximation of certain quantities of physical interest, such as the drag coefficient, is estimated in terms of local residuals of the computed solution multiplied by sensitivity factors, which are obtained by numerically solving an associated dual problem. In the resulting local error indicators, the effects of spatial and temporal discretization are separated, which allows for the simultaneous adjustment of time step and spatial mesh size. The efficiency of the proposed method for the construction of economical meshes and the quantitative assessment of the error is illustrated by several test examples. Copyright © 2012 John Wiley & Sons, Ltd.
Rab4 and Rab5 GTPase are required for directional mobility of endocytic vesicles in astrocytes
Authors: Potokar Maja , Lacovich Valentina , Chowdhury Helena H. , Kreft Marko , Zorec Robert 
Published: January 2012

AbstractRab4 and Rab5 GTPases are key players in the regulation of endocytosis. Although their role has been studied intensively in the past, it is still unclear how they regulate vesicle mobility. In particular, in astrocytes, the most abundant glial cells in the brain, vesicles have been shown to exhibit nondirectional and directional mobility, which can be intermittent, but the underlying switching mechanisms are not known. By using quantitative imaging, we studied the dynamics of single vesicle movements in astrocytes in real time, by transfecting them with different GDP‐ and GTP‐locked mutants of Rab4 and Rab5. Along with the localization of Rab4 and Rab5 on early and late endocytic compartments, we measured the apparent vesicle size by monitoring the area of fluorescent puncta and determined the patterns of vesicle mobility in the presence of wild‐type and Rab mutants. Dominant‐negative and dominant‐positive mutants, Rab4 S22N, Rab5 S34N and Rab4 Q67L, Rab5 Q79L, induced an increase in the apparent vesicle size, especially Rab5 mutants. These mutants also significantly reduced vesicle mobility in terms of vesicle track length, maximal displacement, and speed. In addition, significant reductions in the fraction of vesicles exhibiting directional mobility were observed in cells expressing Rab4 S22N, Rab4 Q67L, Rab5 S34N, and Rab5 Q79L. Our data indicate that changes in the GDP‐GTP switch apparently not only affect fusion events in endocytosis and recycling, as already proposed, but also affect the molecular interactions determining directional vesicle mobility, likely involving motor proteins and the cytoskeleton. © 2012 Wiley Periodicals, Inc.
The moderating effects of organizational context on the relationship between voluntary turnover and organizational performance: Evidence from Korea
Authors: Kwon Kiwook , Chung Kweontaek , Roh Hyuntak , Chadwick Clint , Lawler John J. 
Published: January 2012

AbstractScholars have suggested that the relationship between voluntary turnover and organizational performance can be moderated by the organizational context in which turnover occurs. However, there are few empirical studies that examine such moderating effects. Using a sample of 161 firms in South Korea, this study investigates how the relationship between voluntary turnover and organizational performance is moderated by three context variables: (1) the degree of organizational usage of employee involvement practices, (2) the degree of organizational investment in employee training and development, and (3) the availability of potential workers. The results demonstrate that employee involvement practices significantly amplify the negative relationship between voluntary turnover and organizational performance, give marginal support for moderation from the availability of potential workers, and provide no support for moderation from the degree of organizational investment in employee training and development. We discuss theoretical and practical implications of this study for enriching our understanding of the relationship between voluntary turnover and organizational performance. © 2012 Wiley Periodicals, Inc.
Theory‐driven development of a comprehensive turnover‐attachment motive survey
Authors: Maertz Carl P. , Boyar Scott L. 
Published: January 2012

AbstractRecent studies propose a theoretical framework of “eight forces” that purportedly captures all the distinct motives causing voluntary turnover decisions. Based on this framework, we develop the Turnover‐Attachment Motive Survey (TAMS) consisting of 18 scales, the most comprehensive model‐based turnover antecedent survey to date, facilitating more fully specified research models and more systematic diagnoses of turnover causes. Moreover, findings support behavioral inertia against quitting, psychological dissonance costs of quitting, supervisor continuance attachment, and coworker continuance attachment as significant predictors of turnover behavior for the first time in the literature. Overall, findings do suggest that our 18‐scale survey demonstrated adequate psychometric properties to justify its further use and development. We finally discuss the many uses of the TAMS for both turnover researchers and practitioners. © 2012 Wiley Periodicals, Inc.
Small is beautiful: Implications of reliability and statistical power for testing the efficacy of HR interventions
Authors: Horwitz Sujin K. , Horwitz Irwin B. 
Published: January 2012

AbstractThe development of optimal human resource practices is often contingent on the accurate statistical testing of potential interventions. Testing the efficacy of HR interventions can be enhanced by taking additional measures to improve statistical power, but the traditional means of increasing power through sample size are often beyond the cost and ability of HR professionals to pursue. This article, therefore, focuses on measurement procedures as an alternative way to increase statistical power for detecting HR intervention effects. Selection of reliable and appropriate measures and subsequent instrumentation are examined as efficacious and cost‐beneficial techniques that can be employed during the planning and designing stage of a study for augmenting statistical power to optimize business decision making. © 2012 Wiley Periodicals, Inc.
Shocks and final straws: Using exit‐interview data to examine the unfolding model's decision paths
Authors: Kulik Carol T. , Treuren Gerry , Bordia Prashant 
Published: January 2012

AbstractThe unfolding model emphasizes the role of shocks (jarring events that initiate exit cognitions) in the turnover process. In contrast to earlier survey‐based research, we used exit interviews to classify organizational leavers along the model's paths. The data provide support for the model but highlight several aspects of shocks not addressed by previous research. Employees on the same path may experience distinctly different shock subgroups (e.g., work or nonwork), some employees require shock combinations (e.g., push and pull shocks) to motivate leaving, and some dissatisfied employees experience shock‐like events (final straws) that confirm previous exit cognitions rather than initiate them. The research demonstrates how organizations can use exit interviews to better understand their employee exit patterns. © 2012 Wiley Periodicals, Inc.
Increasing HR's strategic participation: The effect of HR service quality and contribution expectations
Authors: Uen Jin Feng , Ahlstrom David , Chen Shu‐Yuan , Tseng Pai‐Wei 
Published: January 2012

AbstractStrategic participation is important for HR professionals who wish to have increased influence in their organizations. While a number of previous studies have suggested a link between strategic human resource management and firm performance, few have explored the specific factors enabling HR strategic participation. This study examines the impact of HR service quality and expectations of HR contributions on HR strategic participation. A total of 244 survey responses were received from 42 companies in Taiwan. All hypotheses were supported, thus signifying significant relationships between HR service quality, expectations of HR contributions, and HR strategic participation. The study results also indicate that HR professionals are able to proactively increase the value of HR in organizations by enhancing HR service quality and addressing potential internal customers' needs accordingly. © 2012 Wiley Periodicals, Inc.
Why does firm reputation in human resource policies influence college students? The mechanisms underlying job pursuit intentions
Authors: Wayne Julie Holliday , Casper Wendy J. 
Published: January 2012

AbstractBusiness periodicals, such as Fortune magazine, rank organizations in lists such as the “Best Companies to Work For,” providing applicants with information about firms' human resource practices, including pay, benefits, work‐life, and diversity practices. It is not clear what influence this reputational information about HR practices has on applicant interest in pursuing employment or, more important, why it does so. Given that firms invest substantial resources in HR practices to vie for positions on these lists, the current study sought to fill these gaps in the literature. In the 2 (compensation) × 2 (work‐family) × 2 (diversity) factorial design, 232 college students read about magazine rankings in which a firm's reputation in each HR practice was manipulated as ranking either high or low relative to competitors. We examined perceptions of organizational prestige, anticipated organizational support, and anticipated role performance as mechanisms that explain the influence of HR practice reputation on job pursuit intentions. Our results indicate that a firm's reputation in compensation, work‐family, and diversity efforts increase college students' intentions to pursue employment with a firm. They do so because college students perceive that the organization is prestigious, will be supportive, and will foster their job performance. Our results suggest that a strong employer brand derived from employee‐centered HR practices is important for recruiting college students. © 2012 Wiley Periodicals, Inc.
EFFECTS OF IRRIGATION ON SOIL PHYSICO‐CHEMISTRY: A CASE STUDY OF THE TRIFFA PLAIN (MOROCCO)
Authors: Bendra Brahim , Fetouani Sanaa , Laffray Xavier , Vanclooster Marnik , Sbaa Mohamed , Aleya Lotfi 
Published: January 2012

ABSTRACTThe Triffa Plain is the most productive irrigated agricultural zone in north‐eastern Morocco. Irrigated agriculture in (semi‐)arid regions may exert different pressures on soil resources, but in northern Africa these are often poorly documented. A field survey conducted in 2005 to assess soil quality in the region focuses on the soil's physico‐chemical parameters and analyses their spatial dependency on a regional scale. As most of the soils are light‐textured, with poor organic matter content and slightly basic pH, they are vulnerable to soil nutrient depletion. Multivariate analysis shows that organic matter content is well correlated to the soil's P and K content, while the total and active lime correlate well with the alkalinity and pH, which in turn correlate negatively with nitrate content and soil electrical conductivity. The spatial structure of the soil parameters can be modelled using Gaussian semi‐variograms, suggesting consistent spatial structuring of the parameters. The low nutritional status of the soils is compensated by important fertiliser supplements, leading to nutrient imbalances and further environmental deterioration. Copyright © 2012 John Wiley & Sons, Ltd.
Block copolymer arrangement and composition effects on protein conformation using atomic force microscope‐based antigen–antibody adhesion
Authors: Palacio M. L. B. , Schricker S. R. , Bhushan B. 
Published: January 2012

AbstractThe conformational changes of fibronectin (FN) deposited on various block copolymers where one block is composed of poly(methyl methacrylate) (PMMA) and the other block is either poly(acrylic acid) (PAA) or poly(2‐hydroxyethyl methacrylate) (PHEMA) were investigated using a functionalized atomic force microscope (AFM) tip. The tip was modified with an antibody sensitive to the exposure of the arginine–glycine–aspartic acid (RGD) groups in FN. By studying the adhesive interactions between the antibody and the proteins adsorbed on the block copolymer surface and phase imaging, it was found that the triblock copolymers PAA‐b‐PMMA‐b‐PAA and PMMA‐b‐PHEMA‐b‐PMMA, which both have large domain sizes, are conducive to the exposure of the FN RGD groups on the surface. On the basis of these results, it is concluded that the surface chemistry as well as the nanomorphology dictated by the block copolymer arrangement could both tune protein conformation and orientation and optimize cell adhesion to the biomaterial surface. © 2012 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2012.
Downstream of downstream processing: development of recycling strategies for biopharmaceutical processes
Authors: Grote Florian , Ditz Reinhard , Strube Jochen 
Published: January 2012

AbstractBACKGROUND: Downstream processing plays a crucial role in biotechnological production processes. Product concentration and purification require complex, multi‐step operations, using significant amounts of chemical and auxiliary material. Today, design and optimization is important because the process development of biotechnological products is becoming more and more expensive. It is of great importance to improve sustainable development of eco‐efficient products and processes. Integrated process and product development leads to more efficient use of raw materials.RESULTS: A new stepwise approach is proposed to develop recycling strategies for biopharmaceutical products, which can be implemented within an existing and approved process environment. This article describes the approach in detail and exemplifies the methodical procedure for characteristic reference processes. The theoretical recycling and separation tasks as well as possible strategies are defined and evaluated experimentally. An experimental model parameter determination in small scale is shown. In addition, concrete solutions are discussed due to solving regulatory constraints addressing comparability studies.CONCLUSION: It is shown that development with the aim of intensification and full integration of the individual steps of bioprocess production (modules, unit operations) leads to an improvement in every single step at the same time. It follows clearly that consistent implementation represents a meaningful contribution to next generation bioproduction design. Copyright © 2012 Society of Chemical Industry
Improved B1 homogeneity of 3 tesla breast MRI using dual‐source parallel radiofrequency excitation
Authors: Rahbar Habib , Partridge Savannah C. , DeMartini Wendy B. , Gutierrez Robert L. , Parsian Sana , Lehman Constance D. 
Published: January 2012

AbstractPurpose:To compare breast MRI B1 homogeneity at 3 Tesla (T) with and without dual‐source parallel radiofrequency (RF) excitation.Materials and Methods:After institutional review board approval, we evaluated 14 consecutive breast MR examinations performed at 3T that included three‐dimensional B1 maps created separately with conventional single‐source and dual‐source parallel RF excitation techniques. We measured B1 values (expressed as % of intended B1) on each B1 map at nipple level in multiple bilateral locations: anterior, lateral, central, medial, and posterior. Mean whole breast and location specific B1 values were calculated and compared between right and left breasts using paired t‐test.Results:Mean whole breast B1 values differed significantly between right and left breasts with standard single‐source RF excitation (difference L‐R, Δ = 9.2%; P < 0.001) but not with dual‐source parallel RF excitation (Δ = 2.3%; P = 0.085). Location specific B1 values differed significantly between right and left on single‐source in the lateral (P = 0.014), central (P = 0.0001), medial (P = 0.0013), and posterior (P < 0.0001) locations. Conversely, mean B1 values differed significantly on dual‐source parallel RF excitation for only the anterior (P = 0.030) and lateral (P = 0.0003) locations.Conclusion:B1 homogeneity is improved with dual‐source parallel RF excitation on 3T breast MRI when compared with standard single‐source RF excitation technique. J. Magn. Reson. Imaging 2012;35:1222‐1226. © 2012 Wiley Periodicals, Inc.
Four‐dimensional phase contrast MRI with accelerated dual velocity encoding
Authors: Nett Elizabeth J. , Johnson Kevin M. , Frydrychowicz Alex , Del Rio Alejandro Munoz , Schrauben Eric , Francois Christopher J. , Wieben Oliver 
Published: January 2012

AbstractPurpose:To validate a novel approach for accelerated four‐dimensional phase contrast MR imaging (4D PC‐MRI) with an extended range of velocity sensitivity.Materials and Methods:4D PC‐MRI data were acquired with a radially undersampled trajectory (PC‐VIPR). A dual Venc (dVenc) processing algorithm was implemented to investigate the potential for scan time savings while providing an improved velocity‐to‐noise ratio. Flow and velocity measurements were compared with a flow pump, conventional 2D PC MR, and single Venc 4D PC‐MRI in the chest of 10 volunteers.Results:Phantom measurements showed excellent agreement between accelerated dVenc 4D PC‐MRI and the pump flow rate (R2 ≥ 0.97) with a three‐fold increase in measured velocity‐to‐noise ratio (VNR) and a 5% increase in scan time. In volunteers, reasonable agreement was found when combining 100% of data acquired with Venc = 80 cm/s and 25% of the high Venc data, providing the VNR of a 80 cm/s acquisition with a wider velocity range of 160 cm/s at the expense of a 25% longer scan.Conclusion:Accelerated dual Venc 4D PC‐MRI was demonstrated in vitro and in vivo. This acquisition scheme is well suited for vascular territories with wide ranges of flow velocities such as congenital heart disease, the hepatic vasculature, and others. J. Magn. Reson. Imaging 2012;35:1462–1471. © 2012 Wiley Periodicals, Inc.
Quantification of holmium‐166 loaded microspheres: Estimating high local concentrations using a conventional multiple gradient echo sequence with S0‐fitting
Authors: van de Maat Gerrit H. , Seevinck Peter R. , Bos Clemens , Bakker Chris J.G. 
Published: January 2012

AbstractPurpose:To provide a best estimate of the R value and hence of the local concentration of highly paramagnetic holmium‐166 loaded microspheres (HoMS) in voxels for which R cannot be characterized by conventional fitting of multigradient echo (MGE) data because of fast signal decay due to high local concentrations.Materials and Methods:A postprocessing method, S0‐fitting, was implemented in a conventional R fitting method that is used for quantification of HoMS. S0‐fitting incorporates the estimated initial amplitude of the free induction decay (FID) curve, S0, of neighboring voxels into the fitting procedure for voxels for which the conventional algorithm failed. The method was applied to HoMS in vitro and ex vivo in a rabbit liver. The performance of the S0‐fitting method was evaluated by comparing results qualitatively and quantitatively with results obtained with quantitative ultrashort TE imaging (qUTE).Results:Applying S0‐fitting provided a best estimate for R up to a value of about 2300 s−1 compared with a maximum value of about 1000 s−1 that could be characterized using conventional fitting. A good agreement was observed both qualitatively and quantitatively for in vitro experiments as well as for ex vivo rabbit liver experiments between results obtained with S0‐fitting and results obtained with qUTE imaging.Conclusion:S0‐fitting is a postprocessing method that can provide a best estimate of high R values that cannot be characterized by conventional relaxometry. The method can be applied to conventional MGE datasets and was shown to be beneficial for quantification of high local concentrations of holmium‐loaded microspheres. J. Magn. Reson. Imaging 2012;35:1453–1461. © 2012 Wiley Periodicals, Inc.