bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elucidation of π‐Conjugation Modes in Diarene‐Fused 1,2‐Dihydro‐1,2‐diborin Dianions
Authors: Araki Takafumi , Wakamiya Atsushi , Mori Kenji , Yamaguchi Shigehiro 
Published: April 2012

AbstractA series of diarene‐fused 1,2‐dihydro‐1,2‐diborins were prepared as a new BB‐bond‐embedded polycyclic π‐electron system. The reduction of these compounds with metals produced their corresponding dianions, the π‐conjugation modes of which varied from 6π‐conjugation within the central 1,2‐diborin skeleton to 14π peripheral conjugation over the tricyclic skeleton, depending on the nature of the reduced biaryl framework. Moreover, the countercation to the dianions had a significant effect on the absorption spectra, with a dramatic color change from yellow to deep blue, depending on the distance between the tricyclic dianion skeleton and the countercation.
CdS nanoparticles‐ enhanced chemiluminescence and determination of baicalin in pharmaceutical preparations
Authors: Chen Xiaolan , Tan Xinmei , Wang Jianxiu 
Published: April 2012

ABSTRACTCdS nanoparticles (CdS NPs) of different sizes were synthesized by the citrate reduction method. It was found that CdS NPs could enhance the chemiluminescence (CL) of the luminol‐potassium ferricyanide system and baicalin could inhibit CdS NPs‐enhanced luminol‐potassium ferricyanide CL signals in alkaline solution. Based on this inhibition, a flow‐injection CL method was established for determination of baicalin in pharmaceutical preparations and human urine samples. Under optimized conditions, the linear range for determination of baicalin was 5.0 x 10−6 to 1.0 x 10−3 g/L. The detection limit at a signal‐to‐noise ratio of 3 was 1.7 x 10 −6 g/L. CL spectra, UV‐visible spectra and transmission electron microscopy (TEM) were used to investigate the CL mechanism. The method described is simple, selective and obviates the need of extensive sample pretreatment. Copyright © 2012 John Wiley & Sons, Ltd.
Tools for characterizing the whole‐cell bio‐oxidation of alkanes at microscale
Authors: Grant Chris , da Silva Damas Pinto Ana Catarina , Lui Hai‐Po , Woodley John M. , Baganz Frank 
Published: April 2012

AbstractThis article describes the first reported microwell whole‐cell bioconversion using a water immiscible substrate that matches the specific activity and yield achieved in a 1.2 L stirred tank bioreactor. Maximum yields of 0.6 g/Ltotal 1‐dodecanol achieved in 24 h compare favorably to 0.28 g/Ltotal 1‐dodecanol after 48 h obtained in a stirred tank reactor. Using the microwell platform we present a rapid and systematic approach to identify the key bottlenecks in the bio‐oxidation of long‐chain alkanes using Escherichia coli expressing the alkane hydroxylase (alkB) complex. The results indicate that mass transfer rates limit productivity in the n‐dodecane bio‐oxidation system, rather than inherent enzyme activity. Furthermore, substrate solubility, oxygen availability and glucose concentration act cooperatively to affect the amount of by‐product, dodecanoic acid. Optimizing these factors using response surface methodology enabled specific yields of 1‐dodecanol to increase eightfold and overoxidation to dodecanoic acid to be reduced from 95% to 55%. This resulted in specific activities of 10.4 µmol/min/gdcw on n‐dodecane; approximately 50% of the 21 µmol/min/gdcw obtained with n‐octane. For the first time, this in vivo rate difference is within the range reported for the purified enzyme. Finally, the results obtained also provide strong evidence that the mechanism of E. coli interaction with alkanes is mainly via uptake of alkanes dissolved in the aqueous phase rather than by direct cell–droplet contact. Biotechnol. Bioeng. 2012;109: 2179–2189. © 2012 Wiley Periodicals, Inc.
(S)‐Naproxen as a platform to develop chiral derivatizing reagent for reversed‐phase high‐performance liquid chromatographic enantioseparation of analytes having a carbonyl functional group
Authors: Bhushan Ravi , Lal Manohar 
Published: April 2012

ABSTRACT(S)‐Naproxen was used to synthesize a chiral reagent, (S)‐2‐(6‐methoxynaphthalen‐2‐yl)propanehydrazide, by itsreaction with hydrazine hydrate in the presence of dicyclohexylcarbodiimide as coupling agent. The reagent was characterized and its chiral purity was established. It was used as a chiral derivatizing reagent for the synthesis of hydrazone diastereomers, under microwave irradiation, of certain chiral aldehydes and ketones. The respective diastereomers were separated by reversed‐phase high‐performance liquid chromatography using a binary solvent combination containing trifluoroacetic acid. The diastereomers were detected at 231 nm. The method was validated for accuracy, precision, and limit of detection (LOD). For a series of hydrazones the LOD was found to be in the range 1.62–1.65 pmol/mL. Copyright © 2012 John Wiley & Sons, Ltd.
Estimation of raw material performance in mammalian cell culture using near infrared spectra combined with chemometrics approaches
Authors: Lee Hae Woo , Christie Andrew , Liu Jun Jay , Yoon Seongkyu 
Published: April 2012

AbstractUnderstanding variability in raw materials and their impacts on product quality is of critical importance in the biopharmaceutical manufacturing processes. For this purpose, several spectroscopic techniques have been studied for raw material characterization, providing fast and nondestructive ways to measure quality of raw materials. However, investigations of correlation between spectra of raw materials and cell culture performance have been scarce due to their complexity and uncertainty. In this study, near‐infrared spectra and bioassays of multiple soy hydrolysate lots manufactured by different vendors were analyzed using chemometrics approaches in order to address variability of raw materials as well as correlation between raw material properties and corresponding cell culture performance. Principal component analysis revealed that near‐infrared spectra of different soy lots contain enough physicochemical information about soy hydrolysates to allow identification of lot‐to‐lot variability as well as vendor‐to‐vendor differences. The identified compositional variability was further analyzed in order to estimate cell growth and protein production of two mammalian cell lines under the condition of varying soy dosages using partial least square regression combined with optimal variable selection. The performance of the resulting models demonstrates the potential of near‐infrared spectroscopy as a robust lot selection tool for raw materials while providing a biological link between chemical composition of raw materials and cell culture performance. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012
A combinatorial approach for directing the amount of fibronectin fibrils assembled by cells that uses surfaces derivatized with mixtures of fibronectin and cell binding domains
Authors: Kshatriya Pradnya P. , Karuri Stella W. , Chiang Chunyi , Karuri Nancy W. 
Published: April 2012

AbstractFibrillar fibronectin (FN) has the crucial role of attracting and attaching cells as well as molecules that mediate tissue repair during wound healing. A previous study demonstrated higher extracellular staining of FN fibrils in cells cultured on surfaces tethered with an equimolar mixture of a FN binding domain and FN's cell binding domain, III1‐2 and III9‐10 respectively, than on surfaces with III9‐10 alone. The effect of varying surface amounts of III1‐2 and III9‐10 on the quantity of FN fibrils formed by NIH‐3T3 fibroblasts was examined. GST tagged III1‐2 and III9‐10 were conjugated to polyurethane surfaces and ELISAs were used to identify the experimental design space or the range of concentrations of GST‐III1‐2 and GST‐III9‐10 that demarcated the limits of protein loading on the surface. When GST‐III1‐2 was fixed and GST‐III9‐10 varied within the design space, the amount of FN fibrils measured by immunoblotting detergent insoluble cell lysates was dependent on the ratio of III9‐10 to III1‐2. When the total protein concentration was fixed and the mixture composition of GST‐III1‐2 and GST‐III9‐10 varied such that it optimally covered the design space, a parabolic relationship between FN fibril amount and the ratio of III9‐10 to III1‐2 was obtained. This relationship had a maximum value when the surface was bonded to equal amounts of III1‐2 and III9‐10 (P < 0.05). Thus the ratio of III9‐10 to III1‐2 can be utilized to direct the quantity of FN fibrils formed on surfaces. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Retracted: Notch activation is regulated by an interaction between hCLP46 and chaperone protein calnexin
Authors: Feng Xiaoqin , Liu Lixin 
Published: April 2012

Retraction: The following article from Cell Biochemistry and Function, “Notch activation Is regulated by interaction between hCLP46 and the chaperone protein calnexin” by Xiaoqin Feng and Lixin Liu, published online on 3 April 2012 in Wiley Online Library (www.wileyonlinelibrary.com), has been retracted with agreement from the authors, the journal Editor, Nigel Loveridge, and John Wiley & Sons Ltd. The retraction has been agreed because the paper was submitted without approval from the co‐author, Lixin Liu, and contains data that requires further experimentation in order to support the conclusions fully.ReferenceFeng, X. and Liu, L. (2012), Notch activation is regulated by an interaction between hCLP46 and chaperone protein calnexin. Cell Biochem. Funct. doi: 10.1002/cbf.2825
Characterization and Quantification of Reduced Sites on Supported Vanadium Oxide Catalysts by Using High‐Frequency Electron Paramagnetic Resonance
Authors: Dinse Arne , Carrero Carlos , Ozarowski Andrzej , Schomäcker Reinhard , Schlögl Robert , Dinse Klaus‐Peter 
Published: April 2012

AbstractVOx (1.4–1.7 V nm−2) supported on SBA‐15, Al2O3, or TiO2 was studied before and after exposure to oxidative dehydrogenation of propane (ODP), and pure hydrogen or propane. After treatment, samples were quenched and frozen in quartz vials and characterized by using high‐frequency electron paramagnetic resonance (HF‐EPR). For SBA‐15‐ and Al2O3‐supported vanadia, V4+ sites were the most abundant paramagnetic species, whereas Ti3+ was dominant in TiO2‐supported V2O5. For the quantification of paramagnetic reduced sites, Mn2+ was used as reference. The maximum relative numbers of reduced V4+ or Ti3+ sites were found to increase in the sequence SBA‐15 (11 % V4+/V)<Al2O3 (16 % V4+/V)<TiO2 (21 % Ti3+/V) if hydrogen was used as a reducing agent. Using propane as a reductant, the percentage ratios were found to be SBA‐15 (8 % V4+/V), Al2O3 (18 % V4+/V), and TiO2 (27 % Ti3+/V). The corresponding V4+/V or Ti3+/V percentage ratios for samples exposed to ODP were lower, at 0.08, 9, and 17 %, respectively. The number of paramagnetic non‐V4+ or non‐Ti3+ sites was negligible for Al2O3 and SBA‐15 and in the range of 12–37 % for TiO2‐supported vanadia. The number of reduced sites after oxidation in air and storage in sealed vials is negligible, which indicates that all reduced sites can generally be reoxidized. After reaction in an oxygen‐lean ODP atmosphere, a structureless HF‐EPR pattern was observed for SBA‐15‐supported vanadia, which is tentatively attributed to the formation of two‐dimensional polymeric structures of vanadia. For Al2O3‐supported vanadia, this loss of spectral resolution was less pronounced, which indicates a more defined environment of V4+ sites. The results are discussed in terms of a two‐parameter model, rationalizing the dual influences of reducibility and local structure of redox‐active sites on the ODP reaction.
PEPPSI‐Type Palladium Complexes Containing Basic 1,2,3‐Triazolylidene Ligands and Their Role in Suzuki–Miyaura Catalysis
Authors: Canseco‐Gonzalez Daniel , Gniewek Andrzej , Szulmanowicz Michal , Müller‐Bunz Helge , Trzeciak Anna M. , Albrecht Martin 
Published: April 2012

AbstractA series of PEPPSI‐type palladium(II) complexes was synthesized that contain 3‐chloropyridine as an easily removable ligand and a triazolylidene as a strongly donating mesoionic spectator ligand. Catalytic tests in Suzuki–Miyaura cross‐coupling reactions revealed the activity of these complexes towards aryl bromides and aryl chlorides at moderate temperatures (50 °C). However, the impact of steric shielding was the inverse of that observed with related normal Nheterocyclic carbenes (imidazol‐2‐ylidenes) and sterically congested mesityl substituents induced lower activity than small alkyl groups. Mechanistic investigations, including mercury poisoning experiments, TEM analyses, and ESI mass spectrometry, provide evidence for ligand dissociation and the formation of nanoparticles as a catalyst resting state. These heterogeneous particles provide a reservoir for soluble palladium atoms or clusters as operationally homogeneous catalysts for the arylation of aryl halides. Clearly, the substitution of a normal N‐heterocyclic carbene for a more basic triazolylidene ligand in the precatalyst has a profound impact on the mode of action of the catalytic system.
Resource Efficiency from Today to Beyond Tomorrow
Authors: Woidasky Jörg , Hirth Thomas 
Published: April 2012

AbstractNatürliche Ressourcen sind vor allem Rohstoffe, Boden, Wasser, Luft,, Nahrung und Energie. Weltweit werden jährlich ca. 60 Mrd. t Ressourcen verbraucht – mit steigender Tendenz. Ressourceneffizienz ist daher einer der wichtigsten Schlüssel für nachhaltige Entwicklung. Als Teil des Nachhaltigkeitskonzepts wird sie dabei von der Ebene der Vereinten Nationen über die Europäische Union bis in konkrete F&E‐Inhalte von Unternehmen und Forschungseinrichtungen übersetzt. Der Beitrag zeigt dies beispielhaft an einem neuen Forschungsschwerpunkt: „Molecular Sorting”︁ soll die Wieder‐ und Weiterverwertung von Werkstoffen durch leistungsfähige Trennprozesse bis auf molekulare Ebene ermöglichen.
Removal of lead (II) and cadmium (II) from aqueous solutions using spent Agaricus bisporus
Authors: Xu Heng , Chen Yuxia , Huang Haiyan , Liu Yingyi , Yang Zhirong 
Published: April 2012

AbstractThe sorption of Pb and Cd from aqueous solutions by spent Agaricus bisporus was investigated. The effects of contact time, pH, ionic medium, initial metal concentration, other metal ions presence and ligands were studied in batch experiments at 25°C. Maximum sorption for both metals was found to occur at an initial pH of around 5.5. The equilibrium process was well described by the Langmuir isotherm model, with maximum sorption capacities of 0.2345 and 0.1273 mmol g−1 for Pb and Cd respectively. Kinetic data followed the pseudo‐second‐order kinetic model. The presence of NaCl and NaClO4 caused a reduction in Cd sorption, while Pb sorption was not remarkably affected. The presence of other metals did not affect Pb removal, while the Cd removal was much reduced. HCl or EDTA solutions were able to desorb Cd from the spent Agaricus bisporus (SAB) completely, while an approximately 60% and 15% desorption yield was obtained for Pb when HCl 0.01 mol L−1 or EDTA 0.001 mol L−1 were used, respectively. The results of FTIR, SEM and EDX analysis indicated that other mechanisms, such as surface complexation and electrostatic interactions, must be involved in the metal sorption in addition to ion exchange. © 2012 Canadian Society for Chemical Engineering
Energy‐efficient beaconless geographic routing in energy harvested wireless sensor networks
Authors: Jumira Oswald , Wolhuter Riaan , Zeadally Sherali 
Published: April 2012

SUMMARYWe propose a routing scheme called energy‐efficient beaconless geographic routing with energy supply (EBGRES) for wireless sensor networks. EBGRES provides loop‐free, fully stateless, energy‐efficient source‐to‐sink routing with minimal communication overhead without the help of prior neighborhood knowledge. It locally determines the duty‐cycle of each node, based on an estimated energy budget for each period, which includes the currently available energy, the predicted energy consumption and the energy expected from the harvesting device. In EBGRES, each node sends out the data packet first rather than a control message. By sending a data packet first, EBGRES performs the neighbor selection only among those neighbors that successfully received the data packet. EBGRES uses a three‐way (DATA/ACK/SELECT) handshake and a timer‐assignment function, the Discrete Dynamic Forwarding Delay (DDFD). We investigate the lower and upper bounds on hop count and the upper bound on energy consumption under EBGRES for source‐to‐sink routing. We further demonstrate the expected total energy consumption along a route toward the sink with the proposed EBGRES approach including a lower bound on energy consumption when the node density increases. Copyright © 2012 John Wiley & Sons, Ltd.
Energetic Ionic Compounds Based on the 2‐Tetrazenium Cation
Authors: Miró Sabaté Carles , Jeanneau Erwann , Delalu Henri 
Published: April 2012

AbstractOxidation of 1,1‐dimethylhydrazine leads to the formation of (E)‐1,1,4,4‐tetramethyl‐2‐tetrazene (1). Compound 1 undergoes oxidative addition with chloramine (Cl–NH2) to form the (E)‐1‐aminomethylidene‐1,4,4‐trimethyl‐2‐tetrazenium cation (TAT+) as its chloride salt 2. Metathesis reactions of salt 2 with energetic anion‐transfer reagents lead to the formation of ionic compounds based on the TAT+ cation and the following anions: nitrate 3, perchlorate 4, 5,5′‐azobis(tetrazolate) 5·6H2O, picrate 6, and azide 7. The water of crystallization in compound 5·6H2O can be removed to form the anhydrous material 5. All compounds were characterized by analytical and spectroscopic methods, and the solid‐state structures of salts 2, 3, 4, 5·6H2O, and 6 were determined by low‐temperature X‐ray crystallography. We used preliminary energetic testing to gain insight into the sensitivities of the materials towards impact and friction and we assessed their thermal stability by differential scanning calorimetry (DSC) measurements. Additionally, the heats of formation of the energetic compounds were computed by using quantum mechanical methods (CBS‐4M) and these values were used to determine some performance parameters of interest for the pure compounds and for their formulations with an oxidizer. Lastly, we calculated the expected decomposition gases of the pure compounds as well as those of the mixtures with an oxidizer.
A C2‐Symmetric Pool Based Flexible Strategy: An Enantioconvergent Synthesis of (+)‐Valiolamine and (+)‐Valienamine
Authors: Lo Hong‐Jay , Chen Cheng‐Yih , Zheng Wei‐Lin , Yeh Shang‐Ming , Yan Tu‐Hsin 
Published: April 2012

AbstractA new enantioconvergent strategy directed toward the synthesis of glucosidase inhibitors was developed by using a C2‐symmetric element within the chiral pool and by applying an iodine‐promoted cyclization of an unsaturated carbonimidothioate for the regio‐ and diastereocontrolled installation of amino and hydroxy units. Not only does this simple flexible strategy provide a convergent concise approach to (+)‐valiolamine (1), but it can also be readily adopted for the synthesis of (+)‐valienamine (2). Commercially available and cheap C2‐symmetric D‐tartaric acid served as the chiral building block.
Photo‐ and Thermal‐Induced Isomerization of Diels–Alder Adducts of Pentacene and TCNE
Authors: Johns Valentine K. , Shi Zheng , Hu Wenfang , Johns Jaime B. , Zou Shengli , Liao Yi 
Published: April 2012

AbstractHerein we report the formation of the second‐ring Diels–Alder adduct together with the central‐ring adduct in a reaction of pentacene and tetracyanoethylene at room temperature. DFT calculations showed that the difference between the free energy of the two isomers is about 3.9 kcal/mol. Photo‐ and thermal‐induced isomerization between the central‐ring adduct and the second‐ring adduct were studied in solution and in polymer films. In solution, the less‐stable second‐ring adduct can be converted into the more‐stable central‐ring adduct either thermally or photochemically, but the reverse transformation does not occur. In a polymer matrix, isomerization can be photochemically induced in both directions at different wavelengths, which results in a photoswitchable system. Formation of pentacene in the photochemical experiments was also observed, which supports an isomerization process involving a photo‐retro‐Diels–Alder reaction.
Effort in the face of difference: Feeling like a non‐prototypical group member motivates effort
Authors: Okimoto Tyler G. , Wrzesniewski Amy 
Published: April 2012

AbstractThree studies examined the relationship between individuals' perceived “prototypicality” in a group, their subsequent self‐presentation goals, and individual effort in that group. Consistent with the finding that feelings of marginal ingroup membership status elicit a desire to seek stronger social connections within ingroups, we predicted that non‐prototypical group members will have more salient self‐presentation goals than prototypical members, and as such will exert more individual effort to exhibit the value of their membership to the group. Correlational Study 1 confirmed that non‐prototypical group members may be more likely than prototypical members to volunteer for activities that would benefit their group. Two experimental studies were then conducted to test the causal influence of feelings of prototypicality while also identifying theoretically relevant moderating conditions of perceived task efficacy (Study 2) and public versus private task performance (Study 3). These findings suggest that effortful performance in groups is partly motivated by the desire to foster social ties. Copyright © 2012 John Wiley & Sons, Ltd.
A nonlinear impact model for simulating the use of rubber shock absorbers for mitigating the effects of structural pounding during earthquakes
Authors: Polycarpou Panayiotis C. , Komodromos Petros , Polycarpou Anastasis C. 
Published: April 2012

SUMMARYDuring strong earthquakes, structural poundings may occur between adjacent buildings because of the limited separation distance and the deformations of their stories. A potential mitigation measure for this problem is the incorporation of layers of soft material, such as rubber, which can act as collision bumpers, in order to prevent the sudden impact pulses. In an effort to investigate the effectiveness of such an impact mitigation measure, relevant numerical simulations and parametric studies can be performed. However, none of the known impact models, which are available in the literature, is able to represent the usage of rubber bumpers with sufficient accuracy. The current study presents a simple but efficient methodology that can be used to simulate the incorporation of rubber layers between neighboring structures with relatively narrow seismic gaps. Such methodology will enable us to numerically investigate the effectiveness of using rubber bumpers to mitigate potential earthquake‐induced pounding. In particular, a new nonlinear inelastic force‐based impact model, able to appropriately describe the behavior of rubber under impact loading, taking also into account the limited thickness of the bumper, is introduced. Finally, a numerical example of simulating earthquake‐induced pounding between two multistory buildings with the consideration of rubber bumpers at impact locations is presented. Copyright © 2012 John Wiley & Sons, Ltd.