bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pressure drop optimisation in design of multi‐stream plate‐fin heat exchangers, considering variable physical properties
Authors: Tahouni Nassim , Miryahyaie Samira , Joda Fatemeh , Fallahi Hamid Reza , Panjeshahi Mohammad Hassan 
Published: January 2013

AbstractA modified method for the design of multi‐stream plate‐fin heat exchangers that considers variable physical properties is proposed in this paper. The new method, based on Pinch Technology, exploits the dependency of physical properties (heat capacity, viscosity, density and thermal conductivity) on temperature variations. A set of temperature correction factors based on variable physical properties is derived for the hot and cold streams of a multi‐stream heat exchanger. This allows calculation of effective stream pressure drops, which can lead to a valid trade‐off between operating and capital cost in the targeting stage. Accordingly, composite curves are constructed; based on the enthalpy intervals, the multi‐stream heat exchanger is subdivided into a number of block sections. A plate‐fin heat exchanger is then designed for each section by maximising the allowable effective pressure drops. Next, using a Genetic Algorithm, the method is completed in order to optimise the pressure drop of streams. Therefore, fin types for each individual stream are considered as optimising variables. By taking the variable physical properties of each stream into account and using the best fin selection, one can achieve accurate results in the design stage.
Ice‐dependent winter survival of juvenile Atlantic salmon
Authors: Hedger R. D. , Næsje T. F. , Fiske P. , Ugedal O. , Finstad A. G. , Thorstad E. B. 
Published: January 2013

AbstractChanges in snow and ice conditions are some of the most distinctive impacts of global warming in cold temperate and Arctic regions, altering the environment during a critical period for survival for most animals. Laboratories studies have suggested that reduced ice cover may reduce the survival of stream dwelling fishes in Northern environments. This, however, has not been empirically investigated in natural populations in large rivers. Here, we examine how the winter survival of juvenile Atlantic salmon in a large natural river, the River Alta (Norway, 70°N), is affected by the presence or absence of surface ice. Apparent survival rates for size classes corresponding to parr and presmolts were estimated using capture‐mark‐recapture and Cormack‐Jolly‐Seber models for an ice‐covered and an ice‐free site. Apparent survival (Φ) in the ice‐covered site was greater than in the ice‐free site, but did not depend on size class (0.64 for both parr and presmolt). In contrast, apparent survival in the ice‐free site was lower for larger individuals (0.33) than smaller individuals (0.45). The over‐winter decline in storage energy was greater for the ice‐free site than the ice‐covered site, suggesting that environmental conditions in the ice‐free site caused a strong depletion in energy reserves likely affecting survival. Our findings highlight the importance of surface ice for the winter survival of juvenile fish, thus, underpinning that climate change, by reducing ice cover, may have a negative effect on the survival of fish adapted to ice‐covered habitats during winter.
Studies on the Total Synthesis of Hirtellanine A: Regioselective Synthesis of Benzopyran
Authors: Zheng Shu‐yan , Li Xiao‐ping , Tan Hong‐sheng , Yu Chun‐hui , Zhang Jing‐hua , Shen Zheng‐wu 
Published: January 2013

AbstractThe total synthesis of Hirtellanine A was accomplished by two different synthetic approaches. Hirtellanine A was assembled using a one‐pot, tandem acid‐mediated deprotection and tautomerization cascade starting from quinone derivative 23. The key features of the synthesis include a Houben–Hoesch reaction of aryl cyanide 3 with phloroglucinol, a one‐pot sequential boronation, a Suzuki–Miyaura cross‐coupling of aryl bromide 33 with aryl iodide 26, and a base‐mediated regioselective Claisen rearrangement for the benzopyran construction.
Indium‐Promoted Diastereo‐ and Regioselective Propargylation of Chiral Sulfinylimines
Authors: García‐Muñoz M. Jesús , Zacconi Flavia , Foubelo Francisco , Yus Miguel 
Published: January 2013

AbstractThe reaction of different chiral imines 3 derived from aldehydes or ketones with the silylated propargyl bromide 4b under sonication in the presence of indium metal led mainly or exclusively to the formation of protected homopropargylamines 5 in a diastereoselective manner. Of special interest are the ketimine derivatives because the new stereocenter has a quaternary configuration. The selective deprotection of the two protecting groups, the silicon and sulfinyl moieties, was easily achieved by conventional methodologies.
Label‐Free Electrochemical Immunoaffinity Sensor Based on Impedimetric Method for Pesticide Detection
Authors: Tran H. V. , Reisberg S. , Piro B. , Nguyen T. D. , Pham M. C. 
Published: January 2013

AbstractWe present a new approach using a conducting polymer to combine immunoaffinity and electrochemical impedance spectroscopy for atrazine detection. The system is based on a competitive complexation between anti‐atrazine antibody and either atrazine present in the analyzed sample or hydroxyatrazine immobilized on the sensor surface. The process allows to detect atrazine at a very low detection limit (0.2 ng L−1) in a true label‐free format (no redox probe added in solution) by following changes in the electrochemical impedance of the sensor.
The effect of wine closures on volatile sulfur and other compounds during post‐bottle ageing
Authors: He Juan , Zhou Qin , Peck Jim , Soles Rollin , Qian Michael C. 
Published: January 2013

ABSTRACTThe effect of wine closures on volatile composition during post‐bottle ageing was investigated for Pinot Noir and Chardonnay wines. Natural cork, synthetic cork and screw caps with Saran–tin, Saranex and low density polyethylene (LDPE) liners were investigated over 3 years of storage. Dissolved O2 and SO2 as well as colour were monitored. Volatile sulfur compounds, esters, terpene alcohols, and C13‐norisoprenoids were quantified every 6 months over 3 years. The results showed that the LDPE screw cap gave the highest dissolved oxygen, lowest free SO2 and total SO2 in both wines, while the Saran–tin screw cap gave the lowest dissolved oxygen and the highest free SO2 and total SO2. A decrease of H2S, methanethiol, and thioacetates were observed during the 3 year ageing process for both wines, and their concentrations decreased most in wines sealed with LDPE screw caps and synthetic closures. The decrease of thioacetates was independent of closure type. The accumulation of dimethyl disulfide during storage was not obvious in these two wines. For both wines, no elevated sulfur compounds under any closure were detected; neither dimethyl disulfide nor dimethyl trisulfide were found in any of the experimental wines. Other volatiles also changed with in bottle ageing. Ethyl esters decreased during ageing, whereas ethyl 2‐methylbutanoate and ethyl 3‐methylbutanoate increased during ageing. Terpene alcohols showed a decreasing trend with ageing, as was β‐damascenone, but β‐ionone remained unchanged in Pinot Noir wine during ageing. Both wines under LDPE closure had the highest acetaldehyde at 36 months of ageing. Wine closure affected the concentration of terpene alcohols and C13‐norisoprenoids. Closure had no impact on nerolidol and citronellol, but LDPE screw‐capped wine had lower concentrations of linalool at 36 months of storage. Both wines with LPDE screw cap closures had higher β‐damascenone. Closure had no effect on β‐ionone and other compounds. Copyright © 2013 John Wiley & Sons, Ltd.
Sparse element for shallow water wave equations on triangle meshes
Authors: Mewis Peter 
Published: January 2013

SUMMARYWithin the mixed FEM, the mini‐element that uses a bubble shape function for the solution of the shallow water wave equations on triangle meshes is simplified to a sparse element formulation. The new formulation has linear shape functions for water levels and constant shape functions for velocities inside each element. The suppression of decoupled spurious solutions is excellent with the new scheme.The linear dispersion relation of the new element has similar advantages as that of the wave equation scheme (generalised wave continuity scheme) proposed by Lynch and Gray. It is shown that the relation is monotonic over all wave numbers. In this paper, the time stepping scheme is included in the dispersion analysis. In case of a combined space–time staggering, the dispersion relation can be improved for the shortest waves.The sparse element is applied in the flow model Bubble that conserves mass exactly. At the same time, because of the limited number of degrees of freedom, the computational efficiency is high. The scheme is not restricted to orthogonal triangular meshes.Three test cases demonstrate the very good accuracy of the proposed scheme. The examples are the classical quarter annulus test case for the linearised shallow water equations, the hydraulic jump and the tide in the Elbe river mouth. Copyright © 2013 John Wiley & Sons, Ltd.
ONE SIZE DOES NOT FIT ALL: INVESTIGATING DOCTORS' STATED PREFERENCE HETEROGENEITY FOR JOB INCENTIVES TO INFORM POLICY IN THAILAND
Authors: Lagarde Mylene , Pagaiya Nonglak , Tangcharoensathian Viroj , Blaauw Duane 
Published: January 2013

ABSTRACTThis study investigates heterogeneity in Thai doctors' job preferences at the beginning of their career, with a view to inform the design of effective policies to retain them in rural areas. A discrete choice experiment was designed and administered to 198 young doctors. We analysed the data using several specifications of a random parameter model to account for various sources of preference heterogeneity. By modelling preference heterogeneity, we showed how sensitivity to different incentives varied in different sections of the population. In particular, doctors from rural backgrounds were more sensitive than others to a 45% salary increase and having a post near their home province, but they were less sensitive to a reduction in the number of on‐call nights. On the basis of the model results, the effects of two types of interventions were simulated: introducing various incentives and modifying the population structure. The results of the simulations provide multiple elements for consideration for policy‐makers interested in designing effective interventions. They also underline the interest of modelling preference heterogeneity carefully. Copyright © 2013 John Wiley & Sons, Ltd.
SIRT2 overexpression in hepatocellular carcinoma mediates epithelial to mesenchymal transition by protein kinase B/glycogen synthase kinase-3β/β-catenin signaling
Authors: Chen Juan , Chan Anthony W.H. , To Ka-Fai , Chen Weixian , Zhang Zhenzhen , Ren Jihua , Song Chunli , Cheung Yue-Sun , Lai Paul B.S. , Cheng Suk-Hang , Ng Margaret H.L. , Huang Ailong , Ko Ben C.B. 
Published: January 2013

Abstract

Sirtuin 1 (SIRT1) has been implicated in telomere maintenance and the growth of hepatocellular carcinoma (HCC). Nevertheless, the role of other sirtuins in the pathogenesis of HCC remains elusive. We found that sirtuin 2 (SIRT2), another member of the sirtuin family, also contributes to cell motility and invasiveness of HCC. SIRT2 is up-regulated in HCC cell lines and in a subset of human HCC tissues (23/45). Up-regulations of SIRT2 in primary HCC tumors were significantly correlated with the presence of microscopic vascular invasion (

P

= 0.001), a more advanced tumor stage (

P

= 0.004), and shorter overall survival (

P

= 0.0499). Functional studies by short hairpin RNA–mediated suppression of SIRT2 expression in HCC cell lines revealed significant inhibition of motility and invasiveness. Depletion of SIRT2 also led to the regression of epithelial-mesenchymal transition (EMT) phenotypes, whereas the ectopic expression of SIRT2 in the immortalized hepatocyte cell line L02 promoted cell motility and invasiveness. Mechanistic studies revealed that SIRT2 regulates the deacetylation and activation of protein kinase B, which subsequently impinges on the glycogen synthase kinase-3β/β-catenin signaling pathway to regulate EMT.

Conclusions:

Our findings have uncovered a novel role for SIRT2 in HCC metastasis, and provide a rationale to explore the use of sirtuin inhibitors in HCC therapy.
Leadership, Creative Problem‐Solving Capacity, and Creative Performance: The Importance of Knowledge Sharing
Authors: Carmeli Abraham , Gelbard Roy , Reiter‐Palmon Roni 
Published: January 2013

AbstractThis article presents two studies that examine whether leader supportive behaviors facilitate knowledge sharing and employee creative problem‐solving capacity, thereby enhancing creative performance. The findings from both studies indicate that leader supportive behaviors are directly and indirectly related, through both internal and external knowledge sharing, to employee creative problem‐solving capacity. In addition, creative problem solving was related to the two dimensions of creative performance—fluency and originality. However, a test of the mediation model indicated that creative problem solving only mediated the relationship between internal knowledge sharing creative performance and originality. These findings highlight the complex process by which leaders facilitate both internal and external knowledge sharing and employee creative problem‐solving capacity, thereby improving employee creative performance.
The Identification of MicroRNAs in Calcisponges: Independent Evolution of MicroRNAs in Basal Metazoans
Authors: Robinson Jeffrey M. , Sperling Erik A. , Bergum Brith , Adamski Marcin , Nichols Scott A. , Adamska Maja , Peterson Kevin J. 
Published: January 2013

AbstractWe present the discovery of microRNAs (miRNAs) in the calcisponges Sycon and Leucosolenia (phylum Calcarea), and potential miRNAs in the homoscleromorph Oscarella carmela (Phylum Homoscleromorpha), expanding the complement of poriferan miRNAs previously known only from the siliceous sponges (demosponges and hexactinellids). Comparison of these miRNAs with those previously described from silicisponges and eumetazoans reveals that these newly described miRNAs are novel, with each metazoan lineage (Silicea, Calcarea, Homoscleromorpha, and Eumetazoa) characterized by a unique and non‐overlapping repertoire of miRNAs (or potential miRNAs as in the case of the homoscleromorphs). Because each group is characterized by a unique repertoire of miRNAs, miRNAs cannot be used to help resolve the contentious issue of sponge mono‐ versus paraphyly. Further, because all sponges are characterized by a similar repertoire of tissue types and body plan organisation, we hypothesize that the lack of conserved miRNAs amongst the three primary sponge lineages is evidence that cellular differentiation and cell type specificity in sponges are not dependent upon conserved miRNAs, contrary to many known cases in eumetazoans. Finally, we suggest that miRNAs evolved multiple times independently not only among eukaryotes, but even within animals, independently evolved miRNAs representing molecular exaptations of RNAi machinery into pre‐existing gene regulatory networks. The role(s) miRNAs play though in sponge biology and evolution remains an open question. J. Exp. Zool. (Mol. Dev. Evol.) 320B:84–93, 2013. © 2013 Wiley Periodicals, Inc.
Crowd Flight in Response to Police Dispersal Techniques: A Momentary Lapse of Reason?
Authors: Cocking Chris 
Published: January 2013

AbstractThere has been much debate about the use of certain public order policing tactics in Britain in response to the disorder seen in recent years. This paper explored the use of an indiscriminate public order tactic that has received comparatively less attention, that of crowd dispersal techniques. More specifically, the use of police charges (either by mounted police or on foot) and subsequent collective flight was investigated. An interview study was conducted with 20 participants who experienced such charges at protests in English cities. Thematic analysis of the data found that although participants reported fear and initial crowd scattering, these instinctive responses were quickly replaced by more socialised reactions, such as co‐operation with others and an increased sense of collective unity. Furthermore, participants reported greater determination to resist what were considered as illegitimate attacks by the police. This increased collective unity was explained in terms of a shared sense of experience that was similar to that found in previous crowd behaviour research. It was concluded that rather than fragmenting crowds, the tactic of crowd dispersal can unite previously heterogeneous groups to resist further police charges and so may be counter‐productive as a public order policing strategy. Copyright © 2013 John Wiley & Sons, Ltd.
Isometric handgrip exercise during cardiovascular magnetic resonance imaging: Set‐up and cardiovascular effects
Authors: von Knobelsdorff‐Brenkenhoff Florian , Dieringer Matthias A. , Fuchs Katharina , Hezel Fabian , Niendorf Thoralf , Schulz‐Menger Jeanette 
Published: January 2013

AbstractPurpose:To establish a suitable setup for combining isometric handgrip exercise with cardiovascular magnetic resonance (CMR) imaging and to assess cardiovascular effects.Materials and Methods:Fifty‐three healthy volunteers (31 males, mean age 45 ± 17 years) underwent handgrip exercise in a 3T scanner using a prototype handgrip system and a custom‐made feedback system that displayed the force. Handgrip was sustained at 30% of the maximal contraction for 6–8 minutes. Heart rate, blood pressure (BP), and double product were determined sequentially. Stroke volume was quantified in a subgroup (n = 21) at rest and stress using phase contrast acquisitions.Results:Heart rate increased significantly between rest and stress by 20 ± 13%, systolic / diastolic / mean BP by 15 ± 11% / 20 ± 18% / 17 ± 13%, double product by 37 ± 21%, and cardiac output by 27 ± 16% (each P < 0.001). Stroke volume did not significantly increase (3 ± 9%; P = 0.215). Higher age was associated with reduced increase of stroke volume (P = 0.022) and cardiac output (P < 0.001). Overweight subjects showed less increases in heart rate (P = 0.021) and cardiac output (P = 0.002).Conclusion:The handgrip exercise during CMR with the presented set‐up leads to considerable hemodynamic changes in healthy volunteers. J. Magn. Reson. Imaging 2013;37:1342–1350. © 2013 Wiley Periodicals, Inc.
Optimizing MRI scan time in the computation of pharmacokinetic parameters (Ktrans) in breast cancer diagnosis
Authors: Jena Amarnath , Mehta Shashi Bhushan , Taneja Sangeeta 
Published: January 2013

Purpose:To assess the effects of reduced scan time in dynamic contrast‐enhanced magnetic resonance imaging (DCE‐MRI) of breast for the evaluation of pharmacokinetic parameters (Ktrans, ve, and kep).Materials and Methods:High temporal resolution DCE‐MRI was performed for calculation of pharmacokinetic parameters (Ktrans, ve, and kep) at different timepoints using an in‐house developed computation scheme adopting the standard model (SM).Results:The receiver operating characteristic (ROC) curve analysis revealed an area under the ROC curve (AUC) of 0.994 for Ktrans at 90 seconds and 0.987 for Ktrans at 60 seconds with a significant decrease in the AUC for Ktrans at 30 seconds (0.669). While ve showed a consistently higher AUC (>0.9) at timepoints ≥40 seconds, the AUC for kep showed a consistent decline with reduced acquisition times.Conclusion:Reducing the acquisition time for the Ktrans and ve measurement up to 60 seconds yields reasonable accuracy for both and can be incorporated in the routine DCE‐MRI protocol for evaluation of enhancing breast lesions. J. Magn. Reson. Imaging 2013;38:573–579. © 2013 Wiley Periodicals, Inc.
Pulmonary perfusion MRI using interleaved variable density sampling and HighlY constrained cartesian reconstruction (HYCR)
Authors: Wang Kang , Schiebler Mark L. , Francois Christopher J. , Del Rio A. Munoz , Cornejo Ma. Daniela , Bell Laura C. , Korosec Frank R. , Brittain Jean H. , Holmes James H. , Nagle Scott K. 
Published: January 2013

Purpose:To demonstrate the feasibility of performing single breathhold, noncardiac gated, ultrafast, high spatial‐temporal resolution whole chest MR pulmonary perfusion imaging in humans.Materials and Methods:Eight subjects (five male, three female) were scanned with the proposed method on a 3 Tesla clinical scanner using a 32‐channel phased‐array coil. Seven (88%) were healthy volunteers, and one was a patient volunteer with sarcoidosis. The peak lung enhancement phase for each subject was scored for gravitational effect, peak parenchymal enhancement and severity of artifacts by three cardiothoracic radiologists independently.Results:All studies were successfully performed by MR technologists without any additional training. Mean parenchymal signal was very good, measuring 0.78 ± 0.13 (continuous scale, 0 = “none” → 1 = “excellent”). Mean level of motion artifacts was low, measuring 0.13 ± 0.08 (continuous scale, 0 = “none” → 1 = “severe”).Conclusion:It is feasible to perform single breathhold, noncardiac gated, ultrafast, high spatial‐temporal resolution whole chest MR pulmonary perfusion imaging in humans. J. Magn. Reson. Imaging 2013;38:751–756. © 2013 Wiley Periodicals, Inc.
Preparation of Reactive Three‐Dimensional Microstructures via Direct Laser Writing and Thiol‐ene Chemistry
Authors: Quick Alexander S. , Fischer Joachim , Richter Benjamin , Pauloehrl Thomas , Trouillet Vanessa , Wegener Martin , Barner‐Kowollik Christopher 
Published: January 2013

AbstractThree‐dimensional microstructures are fabricated employing the direct laser writing process and radical thiol‐ene polymerization. The resin system consists of a two‐photon photoinitiator and multifunctional thiols and olefins. Woodpile photonic crystals with 22 layers and a rod distance of 2 μm are fabricated. The structures are characterized via scanning electron microscopy and focused ion beam milling. The thiol‐ene polymerization during fabrication is verified via infrared spectroscopy. The structures are grafted in a subsequent thiol‐Michael addition reaction with different functional maleimides. The success of the grafting reaction is evaluated via laser scanning microscopy and X‐ray photoelectron spectroscopy. The grafting density is calculated to be close to 200 molecules μm−2.