bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic Kinetic Resolution of 2,3‐Dihydrobenzo[b]furans: Chemoenzymatic Synthesis of Analgesic Agent BRL 37959
Authors: Bongen Patrick , Pietruszka Jörg , Simon Robert Christian 
Published: July 2012

AbstractAn efficient asymmetric synthesis of (S)‐2,3‐dihydrobenzo[b]furan‐3‐carboxylic acid (8 a) and (S)‐5‐chloro‐2,3‐dihydrobenzo[b]furan‐3‐carboxylic acid (8 b) was established. Key to the success was the highly stereoselective enzymatic kinetic resolution of the corresponding methyl or ethyl esters that was further developed into a dynamic process. As a reliable and fast tool for analysing the enantiomeric excess, HPLC coupled with a CD detector was utilized. The route was completed by a Friedel–Crafts acylation of ethyl (S)‐5‐chloro‐2,3‐dihydrobenzo[b]furan‐3‐carboxylate (7 c) followed by saponification leading to (S)‐5‐chloro‐2,3‐dihydrobenzo[b]furan‐3‐carboxylic acid (2), an analgesic agent.
Control of Porosity by Using Isoreticular Zeolitic Imidazolate Frameworks (IRZIFs) as a Template for Porous Carbon Synthesis
Authors: Pachfule Pradip , Biswal Bishnu P. , Banerjee Rahul 
Published: July 2012

AbstractHerein, by using isoreticular zeolitic imidazolate frameworks (IRZIFs) as a template, we report the synthesis, morphology, and gas adsorption properties of porous carbon synthesized by a nanocasting method at 1000 °C, in which furfuryl alcohol (FA) was used as a carbon source. By using IRZIFs with variable porosity as templates, we could achieve control over the carbon porosity and H2 and CO2 uptake. The resultant microporous carbon C‐70, synthesized by using ZIF‐70 as the template, is the most porous (Brunauer–Emmett–Teller (BET) surface area 1510 m2 g−1). Carbon C‐68, synthesized by using ZIF‐68, has moderate porosity (BET surface area 1311 m2 g−1), and C‐69, synthesized by using ZIF‐69, has the lowest porosity in this series (BET surface area 1171 m2 g−1). The porous carbons C‐70, C‐68, and C‐69, which have graphitic texture, have promising H2 uptake capacities of 2.37, 2.15, and 1.96 wt %, respectively, at 77 K and 1 atm. Additionally, C‐70, C‐68, and C‐69 show CO2 uptake capacities of 5.45, 4.98, and 4.54 mmol g−1, respectively, at 273 K and 1 atm. The gas uptake trends shown by C‐70, C‐68, and C‐69 clearly indicate the dependence of carbon porosity on the host template. Moreover, the as‐synthesized carbons C‐70, C‐68, and C‐69 show variable conductivity.
Peptide Chirality Sensing by a Cyclodextrin–Polythiophene Conjugate
Authors: Fukuhara Gaku , Inoue Yoshihisa 
Published: July 2012

AbstractA new cyclodextrin–polythiophene conjugate (CDPT) has been prepared by attaching permethyl‐α‐cyclodextrins to polythiophene (PT) through a hexamethylene tether. Circular dichroism spectral examination of CDPT revealed that only a weak positive Cotton effect (Δε=0.1 M−1 cm−1) was induced at the main band of the PT in dimethyl sulfoxide and similarly weak bisignate signals in pure and aqueous methanol solutions, which indicates that the α‐cyclodextrins appended to PT with a long tether are ineffective in inducing a homochiral structure in the PT backbone. Nevertheless, enantiomeric amino acids and dipeptides added to an aqueous methanolic solution of CDPT caused chirality‐dependent hypochromic changes in the UV/Vis spectra, which enabled us to sense these species and quantitatively determine the enantioselectivity by observing the difference in absorbance upon interaction with pairs of enantiomers. Enantiomeric d,d/l,l‐dipeptide pairs rather than D/L‐amino acid pairs were better differentiated in general, the highest dd/ll selectivity of 13.7 being observed for Phe‐Phe.
Direct α‐Functionalization of Saturated Cyclic Amines
Authors: Mitchell Emily A. , Peschiulli Aldo , Lefevre Nicolas , Meerpoel Lieven , Maes Bert U. W. 
Published: July 2012

AbstractRecent advances in synthetic methods for the direct α‐functionalization of saturated cyclic amines are described. Methods are categorized according to the in situ formed reactive intermediate (α‐amino cation, α‐amino anion, and α‐amino radical). Transition‐metal‐catalyzed reactions involving other intermediates have been treated as a separate and fourth class.
Dendritic Metalloporphyrin–Fullerene Conjugates: Changing the Microenvironment around Redox‐Active Centers and its Impact on Charge‐Transfer Reactions
Authors: Krokos Evangelos , Spänig Fabian , Ruppert Michaela , Hirsch Andreas , Guldi Dirk M. 
Published: July 2012

AbstractPhotophysical investigations on a series of (2,4,6)‐tris‐substituted metalloporphyrin‐fullerene conjugates revealed the effects of an electron‐rich microenvironment surrounding the electron‐donating porphyrin as a function of the metal center. On one hand, for all conjugates—water‐soluble and non‐water‐soluble—ultrafast charge separation was observed upon photoexcitation. On the other hand, when examining the charge recombination dynamics for the non‐water‐soluble conjugates it becomes obvious that the (2,4,6)‐tris‐substitution stabilizes the radical‐ion‐pair state relative to the mono‐substitution in the ortho‐, meta‐, and para‐position. The more efficient protection of the electron‐donating porphyrin from solvation is thought to be the major cause for this impact. Nevertheless, the situation is slightly different for the water‐soluble conjugates. At first glance, the radical‐ion‐pair state lifetimes are, also in the case of the (2,4,6)‐tris‐substitution, longer than for the mono‐substituted ortho‐, meta‐ and para‐conjugates. Upon closer inspection, they fail, however, to exhibit any metal dependence. Competing with the protection from solvation of the dendrons, dipole‐charge interactions impact the stabilization in the polar aqueous environment and, in turn, become the dominant force governing the electron‐transfer dynamics.
Potential Occurrence of MTBE and BTEX in Groundwater Resources of Amman–Zarqa Basin, Jordan
Authors: Al Kuisi Mustafa , Saffarini Ghazi , Yaseen Najal , Alawi Mahmoud 
Published: July 2012

AbstractThis study investigates potential occurrence, distribution, and sources of the newly added gasoline oxygenate, methyl‐tert‐butyl ether (MTBE) and the petroleum derivatives benzene, toluene, ethylbenzene, and xylenes called collectively, BTEX, in Jordan's heavily populated Amman–Zarqa Basin (AZB). It presents the first data on the levels of MTBE and BTEX in the aquifers of this basin. One hundred and seventy‐nine (179) groundwater wells were sampled near petrol service stations, oil refinery storage tanks, car wrecks, bus stations, and chemical industries at different locations in the basin. Headspace GC and purge and trap GC–MS were utilized to determine the target substances in the samples. Concentrations of BTEX varied between no‐detection (minimum) for all of them to 6.6 µg/L (maximum) for ethylbenzene. MTBE was found in few samples but none has exceeded the regulated levels; its concentrations ranged between no‐detection to 4.1 µg/L. However, though the contamination levels are very low they should be considered alarming.
Dramatic Fluorescence Enhancement of Bare Carbon Dots through Facile Reduction Chemistry
Authors: Shen Ran , Song Kai , Liu Huarong , Li Yuesheng , Liu Hewen 
Published: July 2012

AbstractReduction of bare carbon dots (CDs) in aqueous NaBH4 solution is a facile and effective approach to enhance their fluorescence without any surface coverage. CDs are treated with dilute aqueous NaBH4 solutions, enhancing their quantum yields (QYs) successfully from 1.6 % to 16 % which is comparable to semiconductive QDs in aqueous environments. If pristine CDs are treated hydrothermally prior to reduction by NaBH4, QYs reach 40.5 %. This value is among the highest QYs reported for bare CDs in the literature. The approach to enhance fluorescence through chemical reduction is generally applicable to other kinds of CDs synthesized by various methods. Alteration of the chemical structure of the CDs by NaBH4‐reduction is analyzed by 13C NMR, X‐ray photoelectron spectroscopy (XPS) and Raman spectroscopy, which demonstrate that the carbonyl group content is decreased after NaBH4‐reduction, whereas the number of sp3‐type carbon defects is increased. The valence‐band maxima (VBM) near the surface related to the surface energy bands of the CDs are estimated by XPS. VBM data show a semiconducting layer on the surface of the CDs, and the VBM of the CDs decrease with increasing NaBH4‐reduction time. The layered graphite structures in the cores of the CDs are clearly observed by transmission electron microscopy (TEM). CDs could perhaps be regarded as semiconductive surface defect layers formed by chemical erosion over conductive graphite cores. Chemical reduction by NaBH4 changes the surface‐energy bands of the CDs, thus, enhances their fluorescence. The fluorescence properties of aqueous NaBH4‐reduced CDs are also studied for possible biological applications.
On‐Bead Screens Sample Narrower Affinity Ranges of Protein–Ligand Interactions Compared to Equivalent Solution Assays
Authors: Hintersteiner Martin , Buehler Christof , Auer Manfred 
Published: July 2012

AbstractConceptually, on‐bead screening is one of the most efficient high‐throughput screening (HTS) methods. One of its inherent advantages is that the solid support has a dual function: it serves as a synthesis platform and as a screening compartment. Compound purification, cleavage and storage and extensive liquid handling are not necessary in bead‐based HTS. Since the establishment of one‐bead one‐compound library synthesis, the properties of polymer beads in chemical reactions have been thoroughly investigated. However, the characterization of the kinetics and thermodynamics of protein–ligand interactions on the beads used for screening has received much less attention. Consequently, the majority of reported on‐bead screens are based on empirically derived procedures, independent of measured equilibrium constants and rate constants of protein binding to ligands on beads. More often than not, on‐bead screens reveal apparent high affinity binders through strong protein complexation on the matrix of the solid support. After decoding, resynthesis, and solution testing the primary hits turn out to be unexpectedly weak binders, or may even fall out of the detection limit of the solution assay. Only a quantitative comparison of on‐bead binding and solution binding events will allow systematically investigating affinity differences as function of protein and small molecule properties. This will open up routes for optimized bead materials, blocking conditions and other improved assay procedures. By making use of the unique features of our previously introduced confocal nanoscanning (CONA) method, we investigated the kinetic and thermodynamic properties of protein–ligand interactions on TentaGel beads, a popular solid support for on‐bead screening. The data obtained from these experiments allowed us to determine dissociation constants for the interaction of bead‐immobilized ligands with soluble proteins. Our results therefore provide, for the first time, a comparison of on‐bead versus solution binding thermodynamics. Our data indicate that affinity ranges found in on‐bead screening are indeed narrower compared to equivalent interactions in homogeneous solution. A thorough physico‐chemical understanding of the molecular recognition between proteins and surface bound ligands will further strengthen the role of on‐bead screening as an ultimately cost‐effective method in hit and lead finding.
Phosphorylation of CRMP2 is involved in proper bifurcation of the apical dendrite of hippocampal CA1 pyramidal neurons
Authors: Niisato Emi , Nagai Jun , Yamashita Naoya , Nakamura Fumio , Goshima Yoshio , Ohshima Toshio 
Published: July 2012

AbstractThe neural circuit in the hippocampus is important for higher brain functions. Dendrites of CA1 pyramidal neurons mainly receive input from the axons of CA3 pyramidal neurons in this neural circuit. A CA1 pyramidal neuron has a single apical dendrite and multiple basal dendrites. In wild‐type mice, most of CA1 pyramidal neurons extend a single trunk, or alternatively, the apical dendrite bifurcates into two daughter trunks at the stratum radiatum layer. We previously reported the proximal bifurcation phenotype in Sema3A−/−, p35−/−, and CRMP4−/− mice. Cdk5/p35 phosphorylates CRMP2 at Ser522, and inhibition of this phosphorylation suppressed Sema3A‐induced growth cone collapse. In this study, we analyzed the bifurcation points of the apical dendrites of hippocampal CA1 pyramidal neurons in CRMP2KI/KI mice in which the Cdk5/p35‐phosphorylation site Ser522 was mutated into an Ala residue. The proximal bifurcation phenotype was not observed in CRMP2KI/KI mice; however, severe proximal bifurcation of apical dendrites was found in CRMP2KI/KI;CRMP4−/− mice. Cultured hippocampal neurons from CRMP2KI/KI and CRMP2KI/KI;CRMP4−/− embryos showed an increased number of dendritic branching points compared to those from wild‐type embryos. Sema3A increased the number of branching points and the total length of dendrites in wild‐type hippocampal neurons, but these effects of Sema3A for dendrites were notobserved in CRMP2KI/KI and CRMP2KI/KI;CRMP4−/−hippocampal neurons. Binding of CRMP2 to tubulin increased in both CRMP2KI/KI and CRMP2KI/KI:CRMP4−/− brain lysates. These results suggest that CRMP2 and CRMP4 synergistically regulate dendritic development, and CRMP2 phosphorylation is critical for proper bifurcation of apical dendrite of CA1 pyramidal neurons. © 2012 Wiley Periodicals, Inc. Develop Neurobiol, 2013
Sequence polymorphisms in wild, weedy, and cultivated rice suggest seed‐shattering locus sh4 played a minor role in Asian rice domestication
Authors: Zhu Yongqing , Ellstrand Norman C. , Lu Bao‐Rong 
Published: July 2012

AbstractThe predominant view regarding Asian rice domestication is that the initial origin of nonshattering involved a single gene of large effect, specifically, the sh4 locus via the evolutionary replacement of a dominant allele for shattering with a recessive allele for reduced shattering. Data have accumulated to challenge this hypothesis. Specifically, a few studies have reported occasional seed‐shattering plants from populations of the wild progenitor of cultivated rice (Oryza rufipogon complex) being homozygous for the putative “nonshattering” sh4 alleles. We tested the sh4 hypothesis for the domestication of cultivated rice by obtaining genotypes and phenotypes for a diverse set of samples of wild, weedy, and cultivated rice accessions. The cultivars were fixed for the putative “nonshattering” allele and nonshattering phenotype, but wild rice accessions are highly polymorphic for the putative “nonshattering” allele (frequency ~26%) with shattering phenotype. All weedy rice accessions are the “nonshattering” genotype at the sh4 locus but with shattering phenotype. These data challenge the widely accepted hypothesis that a single nucleotide mutation (“G”/“T”) of the sh4 locus is the major driving force for rice domestication. Instead, we hypothesize that unidentified shattering loci are responsible for the initial domestication of cultivated rice through reduced seed shattering.
Population structure of the butternut canker fungus, Ophiognomonia clavigignenti‐juglandacearum, in North American forests
Authors: Broders K. D. , Boraks A. , Sanchez A. M. , Boland G. J. 
Published: July 2012

AbstractThe occurrence of multiple introduction events, or sudden emergence from a host jump, of forest pathogens may be an important factor in successful establishment in a novel environment or on a new host; however, few studies have focused on the introduction and emergence of fungal pathogens in forest ecosystems. While Ophiognomonia clavigignenti‐juglandacearum (Oc‐j), the butternut canker fungus, has caused range‐wide mortality of butternut trees in North America since its first observation in 1967, the history of its emergence and spread across the United States and Canada remains unresolved. Using 17 single nucleotide polymorphic loci, we investigated the genetic population structure of 101 isolates of Oc‐j from across North America. Clustering analysis revealed that the Oc‐j population in North America is made up of three differentiated genetic clusters of isolates, and these genetic clusters were found to have a strong clonal structure. These results, in combination with the geographic distribution of the populations, suggest that Oc‐j was introduced or has emerged in North America on more than one occasion, and these clonal lineages have since proliferated across much of the range of butternut. No evidence of genetic recombination was observed in the linkage analysis, and conservation of the distinct genetic clusters in regions where isolates from two or more genetic clusters are present, would indicate a very minimal or non‐existent role of sexual recombination in populations of Oc‐j in North America.
Investigation and improvement of torque response of control system based on direct torque control in interior permanent magnet synchronous motors
Authors: Inoue Yukinori , Morimoto Shigeo , Sanada Masayuki 
Published: July 2012

AbstractIn this study, we investigate the torque response of a control system that is based on the direct torque control (DTC) principle for an interior permanent magnet synchronous motor (IPMSM). We also propose a gain‐scheduling method for improving the torque response. Reference flux vector calculation (RFVC) DTC is used in this study. In RFVC DTC, a PI controller is used for torque control; this is in contrast to the use of the hysteresis comparator and switching table in basic DTC. In this paper, we present the relationship between the torque response and the gain of the PI controller. This relationship is derived by using the transfer function of the torque control loop. We also examine the difference between the torque responses of two motors that have different machine parameters. The proposed method can be used to realize a torque response that is independent of the operating torque. The simulation results and experimental results presented in this paper show the validity of the derived relationship as well as the effectiveness of the proposed method. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(2): 55–65, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21198
A small‐size self‐propelled Stewart platform
Authors: Torii Akihiro , Banno Masaaki , Ueda Akiteru , Doki Kae 
Published: July 2012

AbstractThis paper describes a self‐propelled Stewart platform. The Stewart platform usually consists of a base platform, a moving platform, and linear actuators connecting the platforms. We use six stacked‐type piezoelectric actuators as linear actuators. Mechanical joints connected the linear actuators and both of the platforms. We inserted electromagnets between the linear actuators and the base platform instead of the mechanical joints. This structure enables the Stewart platform to move on a surface by using the principle of inchworm motion. While the electromagnets fix the linear actuators on the base platform, the proposed Stewart platform realizes a precise 6‐DOF motion. Control signals are designed for small displacement based on inverse kinematics, and for a wide working area based on the principle of inchworm motion. The position and orientation of the moving platform are measured, and experimental results indicate the feasibility of the proposed mechanism. The mechanism is effective for a precise position system which has unlimited working space. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(2): 37–46, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21261
Influence of surface‐conductivity nonuniformity on charge accumulation of GIS downsized model spacer under DC field application
Authors: Iwabuchi Hiroyuki , Donen Taiki , Matsuoka Shigeyasu , Kumada Akiko , Hidaka Kunihiko , Hoshina Yoshikazu , Takei Masafumi 
Published: July 2012

AbstractWhen a DC voltage is applied to an insulating spacer, the electric field distribution around it is determined by the resistivity of the material. Consequently, charges are accumulated on the surface of the insulator, and its breakdown voltage may become low. In this paper, the charge density distribution of the insulator is measured. The measured data indicate that the surface conductance is the main factor in charge accumulation. Therefore, the conductivity of the insulator is also measured, and the influence of the surface conductivity on charge accumulation is examined both experimentally and by numerical computation. It is confirmed that nonuniformity of surface conductivity is responsible for charge accumulation and the conductivity of the insulator in atmospheric‐pressure SF6 is estimated to be $\sigma = 1 \times 10^{-18} \Omega^{-1}$. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(2): 29–36, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22272
A multiagent‐based cooperative voltage and reactive power control
Authors: Ishida Masato , Nagata Takeshi , Saiki Hiroshi , Shimada Ikuhiko , Hatano Ryousuke 
Published: July 2012

AbstractIn order to maintain the system voltage within the optimal range and to prevent voltage instability phenomena before they occur, a variety of phase modifying equipment are installed in optimal locations throughout the power system network and a variety of methods of voltage reactive control are employed. The proposed system divides the traditional method of controlling voltage and reactive power into two subproblems: “voltage control” to adjust the secondary bus voltage of substations, and “reactive power control” to adjust the primary bus voltage. In this system, two types of agents are installed in substations in order to coordinate voltage control and reactive power control. In order to verify the performance of the proposed method, it was applied to a model network system. The results confirm that our proposed method is able to control violent fluctuations in load. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(2): 20–28, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22286
System identification of power network for coordinated setting of PSSs
Authors: Murayama Dai , Mitsumoto Kenji , Takagi Yasuo , Uemura Youichi , Sato Koji , Shirasaki Takashi , Sakamoto Kunio 
Published: July 2012

AbstractThe PSS is a reasonable controller to stabilize the intertie and local oscillations of power networks. PSSs are usually set with the one‐machine infinite‐bus system model. The coordinated setting of the multiple PSSs considering the characteristics of the network is expected to improve stability. For this purpose, the Modal Performance Measure method is used to adjust the PSS parameters. The model is identified by the N4SID identification method. In this paper, the conditions of identification and validation of identification are presented. Identified models are validated by comparison of vector diagrams, impulse response, and so on. Identification of a power network that consists of many generators is successful. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(2): 10–19, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.22287