bluuebunny/crossref_metadata_2025_split huggingface dataset:
Assimilation of point SWE data into a distributed snow cover model comparing two contrasting methods
Authors: Magnusson Jan , Gustafsson David , Hüsler Fabia , Jonas Tobias 
Published: September 2014

AbstractIn alpine and high‐latitude regions, water resource decision making often requires large‐scale estimates of snow amounts and melt rates. Such estimates are available through distributed snow models which in some situations can be improved by assimilation of remote sensing observations. However, in regions with frequent cloud cover, complex topography, or large snow amounts satellite observations may feature information of limited quality. In this study, we examine whether assimilation of snow water equivalent (SWE) data from ground observations can improve model simulations in a region largely lacking reliable remote sensing observations. We combine the model output with the point data using three‐dimensional sequential data assimilation methods, the ensemble Kalman filter, and statistical interpolation. The filter performance was assessed by comparing the simulation results against observed SWE and snow‐covered fraction. We find that a method which assimilates fluxes (snowfall and melt rates computed from SWE) showed higher model performance than a control simulation not utilizing the filter algorithms. However, an alternative approach for updating the model results using the SWE data directly did not show a significantly higher performance than the control simulation. The results show that three‐dimensional data assimilation methods can be useful for transferring information from point snow observations to the distributed snow model.
A new formulation for steady multiaquifer flow: An analytic element for piecewise constant infiltration
Authors: Strack O. D. L. , Namazi Taha 
Published: September 2014

AbstractThis paper contains a new formulation for infiltration inside domains bounded by polygons and its application to problems of steady multiaquifer flow, using the Dupuit‐Forchheimer approximation and assuming vertical flow in the separating layers. An alternative formulation is presented for leaky aquifer systems where infiltration or extraction is given. Existing formulations of multiaquifer flow involve a system of equations that must be solved for the heads in the aquifers. These formulations are abstract, and the relation between the parameters in the solution and physical quantities is hidden. The formulation in the paper aims at linking the system of equations to physical quantities; we have done this in two ways. First, we formulate the problem in terms of leakage potentials, related directly to the leakage through the leaky layers. Second, we introduce the concept of “equilibrated leakage,” leakage that is either the result of infiltration or of some disturbance in the flow pattern, such as that caused by a well. The leakage through the leaky layers tends to some constant value far from a disturbance, e.g., a well, or the boundary of an area of constant infiltration. This concept of equilibrated leakage is useful in practice and helps in understanding the distribution of leakage; we explain this in detail in the paper. The study of problems of steady flow in leaky aquifer systems is inspired by problems of groundwater sustainability, where the overall distribution of flow over long periods of time is important, rather than detailed information.
A Biocompatible “Split Luciferin” Reaction and Its Application for Non‐Invasive Bioluminescent Imaging of Protease Activity in Living Animals
Authors: Godinat Aurélien , Budin Ghyslain , Morales Alma R. , Park Hyo Min , Sanman Laura E. , Bogyo Matthew , Yu Allen , Stahl Andreas , Dubikovskaya Elena A. 
Published: September 2014

AbstractThe great complexity of many human pathologies, such as cancer, diabetes, and neurodegenerative diseases, requires new tools for studies of biological processes on the whole organism level. The discovery of novel biocompatible reactions has tremendously advanced our understanding of basic biology; however, no efficient tools exist for real‐time non‐invasive imaging of many human proteases that play very important roles in multiple human disorders. We recently reported that the “split luciferin” biocompatible reaction represents a valuable tool for evaluation of protease activity directly in living animals using bioluminescence imaging (BLI). Since BLI is the most sensitive in vivo imaging modality known to date, this method can be widely applied for the evaluation of the activity of multiple proteases, as well as identification of their new peptide‐specific substrates. In this unit, we describe several applications of this “split luciferin” reaction for quantification of protease activities in test tube assays and living animals. Curr. Protoc. Chem. Biol. 6:169‐189 © 2014 by John Wiley & Sons, Inc.
Evaluation of Compounds in Primary Human Islet Cell Culture
Authors: Walpita Deepika , Wagner Bridget K. 
Published: September 2014

AbstractThe identification of novel small molecules that promote pancreatic beta‐cell proliferation is an important approach to therapeutic discovery for diabetes. Because human islets are not easy to culture, and attach poorly to plates, it had not been feasible to run high‐throughput phenotypic assays in these cells. Therefore, most laboratories have turned to rodent islets for ease of culture and accessibility. However, rodent islets are not physiologically similar to human islets, either in terms of islet architecture or endocrine cell interactions within the islet, and data generated in rodent islets do not typically translate to human islet biology. To address this challenge, we developed a human islet culture system for high‐throughput screening using a thymidine analog, EdU, to detect beta‐cell replication during screening. Simultaneous monitoring of EdU incorporation and beta cell numbers provides a robust assay for beta‐cell replication, and is now becoming a standard protocol enabling screening in human islets. Curr. Protoc. Chem. Biol. 6:157‐168 © 2014 by John Wiley & Sons, Inc.
Evaluating Thiourea Architecture for Intramolecular [2+2] Photocycloaddition of 4‐Alkenylcoumarins
Authors: Vallavoju Nandini , Selvakumar Sermadurai , Jockusch Steffen , Prabhakaran Manoj Thathamkulam , Sibi Mukund P. , Sivaguru Jayaraman 
Published: September 2014

AbstractThe efficiency of [2+2] photocycloadditions of 4‐alkenylcoumarins was evaluated with various thiourea skeletons to develop thiourea‐based catalysts for promoting photochemical reactions. Our results indicate that the excited state chemistry is dependent on the nature of the thiourea catalyst employed to activate the photoactive substrate.magnified image
Mother Diamine: A Universal Building Block for Making Chiral Ligands from Daughter Diamines to Binol, Binap and Monophos Analogues
Authors: Lee Ansoo , So Soon Mog , Lough Alan J. , Kim Hyunwoo , Chin Jik 
Published: September 2014

Abstract“Mother diamine” (MD) or 1,2‐bis(2‐hydroxy‐phenyl)ethylenediamine can be rapidly transformed to a wide variety of chiral ligands including vicinal diamines and analogs of binol (MDdiol), binap (MDdiphos), and monophos (MDphos). The reactivity and stereoselectivity of the MDphos ligands in Rh‐catalyzed hydrogenation are highly sensitive to the N,N′‐dialkyl substituents.
Endoscopic sinus surgery compared to continued medical therapy for patients with refractory chronic rhinosinusitis
Authors: Smith Kristine A. , Smith Timothy L. , Mace Jess C. , Rudmik Luke 
Published: September 2014

BackgroundThe decision to continue medical therapy or recommend endoscopic sinus surgery (ESS) can be challenging in patients with refractory chronic rhinosinusitis (CRS). The objective of this study was to evaluate continued medical therapy vs ESS for patients with refractory CRS who have severe reductions in baseline disease‐specific quality of life (QoL).MethodsThis was a prospective longitudinal crossover study between August 2011 and June 2013. All patients were >18 years old, diagnosed with CRS based on guideline recommendations, failed initial medical therapy and elected ESS. While waiting for ESS, all patients received continued medical therapy. The preoperative waiting period outcomes (continued medical therapy) were compared to the postoperative outcomes. The primary outcome was change in disease‐specific QoL (22‐item Sinonasal Outcome Test [SNOT‐22]). Secondary outcomes were change in endoscopic grading (Lund‐Kennedy score), medication consumption, and work days missed in the preceding 90 days.ResultsThirty‐one patients were enrolled. Mean baseline SNOT‐22 score was 57.6. After a mean of 7.1 months of continued medical therapy, there was a worsening in SNOT‐22 score (57.6 to 66.1; p = 0.006). After ESS, with a mean postoperative follow‐up of 14.6 months, there was a significant improvement in SNOT‐22 score (66.1 to 16.0; p < 0.001). There was also a significant improvement in endoscopic grading (p < 0.001) coupled with a reduction in both work days lost (p < 0.001) and medication consumption (p < 0.01).ConclusionResults from the study suggest that ESS is a more effective intervention compared to continued medical therapy for patients with refractory CRS who have severe reductions in their baseline disease‐specific QoL.
Synthesis of a Natural Product‐Like Compound Collection through Oxidative Cleavage and Cyclization of Linear Peptides
Authors: Petersen Rico , Le Quement Sebastian T. , Nielsen Thomas E. 
Published: September 2014

AbstractMassive efforts in molecular library synthesis have strived for the development of synthesis methodology which systematically delivers natural product‐like compounds of high spatial complexity. Herein, we present a conceptually simple approach that builds on the power of solid‐phase peptide synthesis to assemble precursor peptides (oligomers) designed to undergo oxidative cascade reactions. By harnessing the structural side‐chain diversity and inherent stereochemical features offered by readily available amino acids (monomers), a proof‐of‐concept collection of 54 skeletally and stereochemically diverse compounds was generated, and selected compounds were elaborated into isoform‐selective metalloprotease inhibitors.
Homogeneous Electrocatalytic Water Oxidation at Neutral pH by a Robust Macrocyclic Nickel(II) Complex
Authors: Zhang Mei , Zhang Ming‐Tian , Hou Cheng , Ke Zhuo‐Feng , Lu Tong‐Bu 
Published: September 2014

AbstractThe development of an earth‐abundant, first‐row water oxidation catalyst that operates at neutral pH and low overpotential remains a fundamental chemical challenge. Herein, we report the first nickel‐based robust homogeneous water oxidation catalyst, which can electrocatalyze water oxidation at neutral pH and low overpotential in phosphate buffer. The results of DFT calculations verify that the OO bond formation in catalytic water oxidation prefers a HOOH coupling mechanism from a cis‐isomer of the catalyst.
Enzymatische Polyketid‐Kettenverzweigung zur Bildung substituierter Lacton‐, Lactam‐ und Glutarimidheterocyclen
Authors: Heine Daniel , Bretschneider Tom , Sundaram Srividhya , Hertweck Christian 
Published: September 2014

AbstractPolyketide werden typischerweise über die Kopf‐Schwanz‐Kondensation von Acyl‐Thioestern gebildet, wobei hoch funktionalisierte lineare Ketten gebildet werden. Bei der Biosynthese des Phytotoxins Rhizoxin dagegen führt ein spezielles Polyketidsynthase(PKS)‐Modul über die Michael‐Addition einer Malonyleinheit an ein α,β‐ungesättigtes Intermediat eine δ‐Lacton‐Kettenverzweigung ein. Um die Substratspezifität des Moduls zu testen, haben wir verschiedene Polyketidmimetika synthetisiert und in einem In‐vitro‐Assay mit dem rekonstituierten PKS‐Modul aus dem Rhizopus‐Symbionten Burkholderia rhizoxinica untersucht. Wir haben den Einfluss der δ‐Substituenten und ihrer Konfiguration untersucht und festgestellt, dass aus Amino‐substituierten Polyketidmimetika die entsprechenden Lactame gebildet werden. Das analoge Carbonsäureamid hingegen wird in ein Glutarimid überführt, eine Struktureinheit, die in zahlreichen Naturstoffen zu finden ist.
Nucleation parameter and size distribution of critical nuclei for nonisothermal polymer crystallization: The influence of the cooling rate and filler
Authors: Kocic Nikola , Lederhofer Sara , Kretschmer Karsten , Bastian Martin , Heidemeyer Peter 
Published: September 2014

ABSTRACTThe nucleation parameter Kg of filled PP, HDPE, and PA6 is determined through nonisothermal DSC measurements. A novel method is proposed for the determination of the size distribution of critical nuclei, where the most commonly found fraction
was obtained as a peak value. The models are tested at different cooling rates and different filler loadings. Kg varies up to a certain cooling rate and afterwards remains constant. The introduction of talc in PP and HDPE facilitates nucleation and thus reduces Kg. An opposite trend occurs upon the addition of bentonite in PA6. The changes of Kg and
are reflected on sample morphology, as confirmed with SAXS. The ratio between the final crystal thickness and
amounts to approx. 2 and thus agrees well with the one listed in literature. The simple linear correlations of the obtained Kg are established with Young's modulus and yield stress. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41433.
[Fe(F20TPP)Cl]‐Catalyzed Amination with Arylamines and {[Fe(F20TPP)(NAr)](PhINAr)} Intermediate Assessed by High‐Resolution ESI‐MS and DFT Calculations
Authors: Liu Yungen , Chen Guo‐Qiang , Tse Chun‐Wai , Guan Xianguo , Xu Zheng‐Jiang , Huang Jie‐Sheng , Che Chi‐Ming 
Published: September 2014

AbstractAmination of CH bonds catalyzed by transition metal complexes via nitrene/imide insertion is an appealing strategy for CN bond formation, and the use of iminoiodinanes, or their in situ generated forms from ‘PhI(OAc)2+primary amides (such as sulfonamides, sulfamates, and carbamates)’, as nitrogen sources for the amination reaction has been well documented. In this work, a ‘metal catalyst+PhI(OAc)2+primary arylamines’ amination protocol has been developed using [Fe(F20TPP)Cl] (H2F20TPP=meso‐tetrakis(pentafluorophenyl)porphyrin) as a catalyst. This catalytic method is applicable for both intra‐ and intermolecular amination of sp2 and sp3 CH bonds (>27 examples), affording the amination products, including natural products such as rutaecarpine, in moderate‐to‐good yields. ESI‐MS analysis and DFT calculations lend support for the involvement of {[Fe(F20TPP)(NC6H4‐p‐NO2)](PhI=NC6H4‐p‐NO2)} intermediate in the catalysis.
Organocatalyzed Cascade Aza‐Michael/Michael Addition for the Asymmetric Construction of Highly Functionalized Spiropyrazolone Tetrahydroquinolines
Authors: Li Jun‐Hua , Du Da‐Ming 
Published: September 2014

AbstractAn organocatalyzed diastereo‐ and enantioselective cascade aza‐Michael/Michael addition of 2‐tosylaminoenones to unsaturated pyrazolones has been developed to afford novel chiral spiropyrazolone tetrahydroquinolines containing three contiguous stereocenters. This cascade reaction proceeded well with 2 mol % chiral bifunctional tertiary amine squaramide catalyst to give the desired products in excellent yields (up to 99 %) with excellent diastereoselectivity (up to >25:1 diastereomeric ratio) and high enantioselectivity (up to 91 % enantiomeric excess).
Mechanistic Origin of Chemoselectivity in Thiolate‐Catalyzed Tishchenko Reactions
Authors: Yu Hai‐Zhu , Tian Xue‐Jiao , Lin Xiang , Hu Guo‐Hua , Dang Zhi‐Min 
Published: September 2014

AbstractThe thiolate‐catalyzed Tishchenko reaction has shown high chemoselectivity for the formation of double aromatic‐substituted esters. In the present study, the detailed reaction mechanism and, in particular, the origin of the observed high chemoselectivity, have been studied with DFT calculations. The catalytic cycle mainly consisted of three steps: 1,2‐addition, hydride transfer, and acyl transfer steps. The calculation results reproduce the experimental observations that 4‐chlorobenzaldehyde acts as the hydrogen donor (carbonyl part in the ester product), while 2‐methoxybenzaldehyde acts as the hydrogen acceptor (alcohol part in the product). The two main factors are responsible for such chemoselectivity: 1) in the rate‐determining hydride transfer step, the para‐chloride substituent facilitates the hydride‐donating process by weakening the steric hindrance, and 2) the ortho‐methoxy substituent facilitates the hydride‐accepting process by stabilizing the magnesium center (by compensating for the electron deficiency).
Output Feedback Control of a Dual‐Excenter Vibration Actuator via qLPV Model and TP Model Transformation
Authors: Kuti József , Galambos Péter , Miklós Ákos 
Published: September 2014

AbstractVibration actuators are widely used in handheld devices to provide vibrotactile feedback or silent notification to the users. In most cases, miniature DC motors with eccentric rotors or the so‐called coin‐type shaftless vibration motors are utilized. The common disadvantage of the single rotor designs is that the frequency and the intensity of the generated vibration cannot be adjusted separately. The construction composed of two independently driven coaxial eccentric rotors – which makes a strongly coupled nonlinear system – allows for the separate control of the frequency and amplitude by the adjustment of the angular speed and the total eccentricity. This paper presents a complete control design approach based on quasi‐linear parameter varying (qLPV) modelling and linear matrix inequality (LMI)‐based synthesis utilizing the tensor product (TP) model transformation to determine the convex polytopic representation of the parameter dependent nonlinear system. The design approach is demonstrated via a concrete numerical example using the parameters of a real dual‐excenter prototype device. The control performance is validated through numerical simulations. This case study goes through a complete nonlinear control problem from the modelling phase to the implementation‐ready controller, while drawing generalizable conclusions for qLPV modelling.
Influences of the MJO on intraseasonal rainfall variability over southern Iran
Authors: Pourasghar Farnaz , Tozuka Tomoki , Ghaemi Hooshang , Oettli Pascal , Jahanbakhsh Saeed , Yamagata Toshio 
Published: September 2014

AbstractUsing daily rainfall data from 183 stations, influences of the Madden‐Julian Oscillation (MJO) on precipitation over southern Iran are examined. When composites of daily rainfall anomalies are constructed by introducing eight phases in the time evolution, wet conditions are observed in MJO phases 1–2 and 7–8. During these phases, atmospheric circulation anomalies favor moisture advection from the western Indian Ocean to southern Iran. In contrast, dry conditions during MJO phases 3 to 6 are associated with advection of drier air from the north.
Effect of sintering temperature on the luminescence properties of Ca0.8Ba0.2TiO3:Pr3+ red‐emitting phosphor
Authors: Mu Yannan , Qiu Min , Zhou Xiaoming , Li Qian , Sun Meiling , Yang Haibin , Fu Wuyou , Yang Lihua , Ma Jinwen 
Published: September 2014

AbstractNanoparticles with the nominal composition Ca0.8Ba0.2Ti03:Pr3+ were prepared using the sol–gel process. Barium nitrate, 4‐hydrated calcium nitrate and praseodymium oxide were used as raw materials. The structural evolution and decomposition processes of the precursors were investigated by powder X‐ray diffraction, differential thermal analysis and thermogravimetric analysis. Crystalline Ca0.8Ba0.2Ti03:Pr3+ could be obtained at 700°C. The photoluminescence properties of the samples were investigated using excitation and emission spectra. Ca0.8Ba0.2Ti03:Pr3+ nanoparticles showed strong red emission, which could be assigned to the typical 1D2→3H4 transition of Pr3+. Furthermore, the study found that sintering temperature and the introduction of Ba2+ influence the decay time of persistent luminescence. Copyright © 2014 John Wiley & Sons, Ltd.
Revisiting size‐exclusion chromatography for measuring structural changes in raw and pretreated mixed hardwoods and switchgrass
Authors: Yang Dong , Parlange Jean‐Yves , Walker Larry P. 
Published: September 2014

ABSTRACTThe study of the biomass porous structure and its role in defining the accessibility of cell‐wall‐degrading enzymes (CWDEs) to the substrate is very important for understanding the cellulase‐cellulose reaction system. Specific pore volume and specific surface area are two important measures of accessibility and a variety of methods have been used to make these measurements. For this study a size exclusion chromatography system was developed to measure specific pore volume and specific surface areas for raw and pretreated mixed‐hardwood and switchgrass. Polyethylene glycol (PEG) probes of known molecular diameter (1.8–13 nm) were allowed to diffuse into the pore structure of the various biomass substrate packed in the column and subsequently eluted to generate high resolution concentration measurements with excellent reproducibility. Replicate measurements of probe concentrations from this system consistently yielded coefficient of variance of less than 1.5%. Our results showed that particle size reduction had a smaller influence on the specific pore volume distribution of raw mixed‐hardwoods, whereas for switchgrass the larger particles yielded a significantly lower estimate for the pore volume distribution compared to the smaller particles. Our results also clearly showed that our bi‐phasic pretreatment yielded the largest increase in pore volume accessibility for mixed‐hardwoods relative to switchgrass. From these results a pore size change mechanism was proposed that could explain the influence of size reduction and pretreatment on pore volume measurements. Biotechnol. Bioeng. 2015;112: 549–559. © 2014 Wiley Periodicals, Inc.
Reversible Amyloid Fiber Formation in the N Terminus of Androgen Receptor
Authors: Asencio‐Hernández Julia , Ruhlmann Christine , McEwen Alastair , Eberling Pascal , Nominé Yves , Céraline Jocelyn , Starck Jean‐Philippe , Delsuc Marc‐André 
Published: September 2014

AbstractMost of the biological effects of androgen hormones are mediated through an intracellular transcription factor, the androgen receptor (AR). This protein presents a long disordered N‐terminal domain (NTD), known to aggregates into amyloid fibers.1 This aggregation property is usually associated with the presence of a poly‐glutamine tract (polyQ), known to be involved in several pathologies.2 The NTD has gain interest recently because potential anti‐prostate‐cancer molecules could target this domain.3 Here, we characterize a conserved region of the NTD (distal from polyQ); it promotes the formation of amyloid fibers under mild oxidative conditions. Unlike most fibrils, which are irreversibly aggregated, the free peptides can be restored from the fibril by the addition of a reducing agent.
Continuous Nanofiltration and Recycle of a Metathesis Catalyst in a Microflow System
Authors: O'Neal Everett J. , Jensen Klavs F. 
Published: September 2014

AbstractContinuous‐flow nanofiltration and recycle of a metathesis catalyst is demonstrated in a small‐scale continuous‐flow system using less than 2 mg of catalyst in 50 h of operation. This length of time corresponds to an average of approximately 70 recycle experiments, where catalyst is partially removed and replaced during each cycle. The small‐scale (2.9 mL total system volume) continuous‐flow catalyst recycle system includes the first fully functional microfluidic organic solvent nanofiltration module using polyimide membranes, a stirred holding tank (<1 mL volume) with a liquid‐level control system to respond to membrane‐flux decline, a membrane reactor using Teflon AF for permeation of the ethylene byproduct, and automated sampling. A turnover number of 935 is obtained for the Hoveyda–Grubbs catalyst. Ruthenium contamination in the product remains less than 1 ppm throughout each experimental run.