bluuebunny/crossref_metadata_2025_split huggingface dataset:
A novel synthesis of iminodiacetic acid: Biocatalysis by whole Alcaligenes faecalis ZJB‐09133 cells from iminodiacetonitrile
Authors: Liu Zhi‐Qiang , Li Fei‐Fei , Cheng Feng , Zhang Tao , You Zhong‐Yu , Xu Jian‐Miao , Xue Ya‐Ping , Zheng Yu‐Guo , Shen Yin‐Chu 
Published: March 2011

AbstractIminodiacetic acid (IDA) has been widely used as an important intermediate in the fine chemical industry. In this study, a novel synthesis route of IDA from iminodiacetonitrile by whole microorganisms was investigated. A strain with the capability of producing nitrilase, ZJB‐09133, was isolated and identified, and later named Alcaligenes faecalis ZJB‐09133. In addition, the detailed biocatalysis of iminodiacetonitrile to produce IDA using ZJB‐09133 was investigated. The results showed that the conversion reached 65.3% in Na2HPO4‐NaH2PO4 buffer of pH 8.0 under the following conditions: cells in the amount of 0.075‐g DCW/L, 1.5% substrate, conversion time of 8 h, and a reaction temperature of 35°C. To the best of our knowledge, this is the first time that the production of IDA using a biocatalysis method has been reported. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Integrated use of ultra scale‐down and financial modeling to identify optimal conditions for the precipitation and centrifugal recovery of milk proteins
Authors: Chhatre Sunil , Pampel Lars , Titchener‐Hooker Nigel J. 
Published: March 2011

AbstractThis article investigates the integrated application of ultra scale‐down (USD) techniques and economic modeling as a means for identifying optimal bioprocess operating conditions. The benefits of the approach are illustrated for the recovery of lactoperoxidase (LPO) from bovine milk. In the process, milk is skimmed to deplete its lipid content, before being subjected to low pH incubation with acetic acid in order to precipitate the primary impurity (casein). Following removal of the solids by disk stack centrifugation, pH adjustment and filtration, cation exchange chromatography is used as a positive mode column step to bind the LPO before it is polished and freeze dried. An economic model of this process was used to identify where greatest product loss occurs and hence where the largest opportunity cost was being incurred. Scale‐down analysis was used to characterize the influence of the critical steps, identified as precipitation and centrifugation, upon LPO recovery. A mathematical model was used to relate the centrifuge feed flowrate and discharge interval to the supernatant yield, and it was shown that increasing the centrifugal solids residence time achieved superior solids de‐watering and so higher product yield, although this also increased the overall processing time. To resolve this conflict, scale‐down data were used again in conjunction with an economic model to determine the most suitable conditions that maximized annual profit and minimized operating costs. The results demonstrate the power of combining USD data with models of economic and process performance in order to establish the best overall operating strategies for biopharmaceutical manufacture. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Mechanistic Study of the Pd/TOMPP‐Catalyzed Telomerization of 1,3‐Butadiene with Biomass‐Based Alcohols: On the Reversibility of Phosphine Alkylation
Authors: Hausoul Peter J. C. , Parvulescu Andrei N. , Lutz Martin , Spek Anthony L. , Bruijnincx Pieter C. A. , Klein Gebbink Robertus J. M. , Weckhuysen Bert M. 
Published: March 2011

AbstractLiquid‐chromatography electrospray‐ionisation mass spectrometry (LC‐ESI‐MS) studies on reaction mixtures of the telomerization of 1,3‐butadiene with biomass‐based polyols revealed that the TOMPP (TOMPP=tris(2‐methoxyphenyl)phosphine) ligand is converted towards the corresponding (2,7‐octadienyl)phosphonium species during catalysis. The extent of ligand alkylation is substrate dependent and was identified as the primary cause of deactivation for carbohydrate substrates with anomeric hydroxyl groups. Coordination studies of the phosphonium cation with [Pd(dba)2] (dba=dibenzylideneacetone) gave insight into the alkylation mechanism and showed that the formation of the phosphonium cation is fully reversible. The reaction yields the key cationic intermediate [Pd(1,2,3,7,8‐η5‐octa‐2,7‐dien‐1‐yl)(TOMPP)]+, which, in the presence of the iodide anion, results in the formation of [Pd(1,2,3‐η3‐octa‐2,7‐dien‐1‐yl)(I)(TOMPP)]. Both complexes were fully characterized by various techniques including single crystal X‐ray crystallography. Based on these results, an extension to the Pd/TOMPP‐catalyzed telomerization mechanism was formulated to include the 2,7‐octadienylphosphonium cation as a ligand reservoir. Catalytic tests show that the use of [Pd(dba)2] as precatalyst improves the telomerization of glucose and xylose.
Quantitative Investigation of a Hybrid Ziegler–Natta Catalyst Support Prepared by Grafting Di(n‐butyl)magnesium onto Partially Dehydroxylated Silica
Authors: Lee Ming‐Yung , Scott Susannah L. 
Published: March 2011

AbstractMgCl2‐modified silica is an important component of some Ziegler–Natta catalysts used in the manufacture of polyethylene. Information about the structure of the dispersed magnesium sites formed by the reaction of di‐n‐butylmagnesium (nBu2Mg) with silica was sought to provide a basis for understanding their subsequent interactions with transition‐metal or co‐catalyst components. From infrared spectra and elemental analysis, we deduced that nBu2Mg reacts with porous silica in two ways: about half (47 %, 0.99 mmol g−1) is grafted through protonolysis by surface hydroxyl groups (SiOH), whereas the other half (53 %, 1.11 mmol g−1) reacts directly with siloxane bonds (SiOSi). In the 29Si and 13C CP/MAS NMR spectra of Sylopol‐2100 silica pretreated at 500 °C then modified with nBu2Mg at room temperature, both alkylsilicon and alkylmagnesium sites are evident. The alkylmagnesium‐modified silica surface is proposed to contain dimers and/or tetramers with the empirical formula [SiOMg(nBu)]n. Upon exposure of nBu2Mg‐modified silica to anhydrous HCl, alkanes are liberated, hydroxyl groups are regenerated, and water is formed. The appearance of water suggests condensation of hydroxyl group pairs, induced by the coordinatively unsaturated nanoclusters (MgCl2)n that arise by ligand exchange on the silica‐supported n‐butylmagnesium oligomers.
Bioinspired Catalyst Design and Artificial Metalloenzymes
Authors: Deuss Peter J. , den Heeten René , Laan Wouter , Kamer Paul C. J. 
Published: March 2011

AbstractMany bioinspired transition‐metal catalysts have been developed over the recent years. In this review the progress in the design and application of ligand systems based on peptides and DNA and the development of artificial metalloenzymes are reviewed with a particular emphasis on the combination of phosphane ligands with powerful molecular recognition and shape selectivity of biomolecules. The various approaches for the assembly of these catalytic systems will be highlighted, and the possibilities that the use of the building blocks of Nature provide for catalyst optimisation strategies are discussed.
NMR enantiodiscrimination by pentafluorophenylcarbamoyl derivatives of quinine: C10 versus C9derivatization
Authors: Uccello‐Barretta Gloria , Vanni Letizia , Berni Margherita Giulia , Balzano Federica 
Published: March 2011

Abstract9‐O‐(Pentafluorophenylcarbamoyl)quinine and 10‐(pentafluorophenylcarbamoyloxy)‐6′‐methoxy‐11‐norcinchonan‐9‐ol, obtained by derivatization of alkaloid double bond, were compared in NMR enantiodiscrimination experiments of selected chiral substrates. Chirality 2011. © 2011 Wiley‐Liss, Inc.
Melamin – Bedeutende Industriechemikalie und toxischer Milchzusatz
Authors: Salzner Jens , Sgoff Dieter , Bader Hans Joachim 
Published: March 2011

AbstractEin wichtiges Bildungsziel des Chemieunterrichts ist es, ungerechtfertigte Ängste gegenüber der Chemie abzubauen. Da eine ablehnende Haltung oft mit der Angst vor einer Gefährdung verbunden ist, sollte im Unterricht sowohl behandelt werden, welchen Nutzen Chemikalien haben als auch, unter welchen Umständen Gefahren von ihnen ausgehen. Am Beispiel des Melamins kann gezeigt werden, wie ein sachgemäßer Umgang mit dieser Substanz zu wertvollen und sicheren Produkten führt, die gleiche Chemikalie aber bei missbräuchlicher Anwendung zur Gefahr für Menschen und Tiere werden kann. Im Folgenden werden sowohl die fachlichen Zusammenhänge erläutert als auch einfache Schulversuche zum Thema Melamin vorgestellt. Diese umfassen zum einen Experimente, die die industrielle Nutzung am Beispiel der Herstellung von Lackharzen zeigen, zum anderen Modellversuche zur Ausfällung von Melamin‐Addukten in der Niere.
Development of Intravascular Contrast Agents for MRI Using Gadolinium Chelates
Authors: Kittigowittana Krisada , Yang Chang‐Tong , Cheah Wai Ching , Chuang Kai‐Hsiang , Tuang Chew‐Yuan , Chang Young‐Tae , Golay Xavier , Bates Roderick W. 
Published: March 2011

AbstractTwo MRI contrast agents (CAs) composed of Gd‐DO3A conjugated to amino acid building blocks derived from glutamic acid (CA1) and lysine (CA2) have been synthesized by using novel alkyne and propionate linkers, and subsequently characterized. In vitro cell viability assays showed insignificant cytotoxicity of both CAs at low concentrations up to 0.2 mM. The longitudinal relaxivities (r1) of CA1 and CA2 measured at 9.4 T are 6.4 and 5.4 mM−1 s−1 in H2O at 25 °C, respectively. Both r1 values are higher than those of CAs in clinical use: Gd‐DTPA (Magnevist, Bayer Schering, Germany) and Gd‐DOTA (Dotarem, Guerbet, France). In vivo imaging in Wistar rats demonstrated considerable signal enhancement (∼50 %) in the brain artery by CA2, but lower signal enhancement (∼30 %) by CA1. In contrast to Dotarem, which showed a similar signal enhancement as CA2, the enhancement by CA2 remained high (∼30 %), even at 52 min post‐injection. This demonstrates that CA2 has a much longer blood half‐life (68.1 min), which could be advantageous for angiography and tissue targeting.
On the identity anonymization of high‐dimensional rating data
Authors: Sun Xiaoxun , Wang Hua , Zhang Yanchun 
Published: March 2011

SUMMARYWe study the challenges of protecting the privacy of individuals in a large public survey rating data. The survey rating data usually contains both ratings of sensitive and non‐sensitive issues. The ratings of sensitive issues involve personal privacy. Although the survey participants do not reveal any of their ratings, their survey records are potentially identifiable by using information from other public sources. None of the existing anonymization principles (e.g. k‐anonymity, l‐diversity, etc.) can effectively prevent such breaches in large survey rating data sets. In this paper, we tackle the problem by defining a principle called (k, epsilon, l)‐anonymity. The principle requires that, for each transaction t in the given survey rating data T, at least (k − 1) other transactions in T must have ratings similar to t, where the similarity is controlled by ε and the standard deviation of sensitive ratings is at least l. We propose a greedy approach to anonymize the survey rating data that scales almost linearly with the input size, and we apply the method to two real‐life data sets to demonstrate their efficiency and practical utility. Copyright © 2011 John Wiley & Sons, Ltd.
A power‐efficient access method by polling for wireless mesh networks
Authors: Hatauchi Takaaki , Fukuyama Yoshikazu , Ishii Misato , Shikura Tatuyuki 
Published: March 2011

AbstractThis paper proposes a power‐efficient access method by polling for wireless mesh networks, which is robust to channel variation due to movement in the surrounding communication environment. In the proposed method, all intermittent nodes periodically repeat ID transmission and a succeeding short period of the receiving state. A node having a packet to transmit goes into a continuous receiving state. Right after receiving an ID transmission from an arbitrary node, it transmits the packet to the node of the preceding ID transmission. In the conventional access method for wireless mesh network, a transmitting node specifies a receiving node well ahead of transmission, leading to a possible change in the wireless link quality at the time of packet transmission from the time of receiving node determination. The proposed access method is robust to wireless channel variation, in the sense that a transmitting node chooses a receiving node just before transmitting the packet. Simulation results show its robustness to wireless channel variations. In the proposed access method, an entire network consumes about one‐sixth the power of a network using the conventional method. © 2011 Wiley Periodicals, Inc. Electron Comm Jpn, 94(4): 20–27, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/ecj.10309
Discotic Nickel Bis(dithiolene) Complexes – Synthesis, Optoelectrochemical and Mesomorphic Properties
Authors: Bui Thanh‐Tuan , Thiebaut Olivier , Grelet Eric , Achard Marie‐France , Garreau‐de Bonneval Bénédicte , Moineau‐Chane Ching Kathleen I. 
Published: March 2011

AbstractFifteen neutral long‐chain‐substituted discotic nickel bis(1,2‐diphenyl‐1,2‐ethenedithiolene) complexes [Ni(dpedt)2], including thirteen new compounds, have been synthesized by new short and efficient synthetic pathways. Physical investigations show that these complexes are thermally stable, possess good electron‐accepting properties, and absorb light strongly in the near‐infrared spectral region. Electrochemical and optical properties of [Ni(dpedt)2] depend moderately on the functionalities attached to the phenyl rings of the complexes. Their LUMO and HOMO energy levels are in the range –4.7 to –5.0 and –5.7 to –6.0 eV, respectively. Two octa(n‐alkoxy)‐substituted complexes exhibit a columnar liquid crystalline phase with hexagonal symmetry. These highly soluble complexes are potential candidates for use as electron‐accepting and electron‐transporting materials for active layers in organic electronic applications, such as field‐effect transistors or photovoltaic devices.
Enantioselective Synthesis of Deoxymannojirimycin Based on Sharpless Asymmetric Epoxidation of a Highly Functionalized Allylic Alcohol
Authors: Lamas Marie‐Céline , Malacria Max , Thorimbert Serge 
Published: March 2011

AbstractAn efficient enantioselective synthesis of deoxymannojirimicin is reported. It is based on the unusual Sharpless asymmetric epoxidation of a silyl‐substituted allylic 1,4‐amino alcohol coupled with a further highly stereoselective intramolecular aldolization. Both enantiomers of deoxymannojirimicin are available. An orthogonally protected polyhydroxylated piperidine was prepared, which could formally lead to other members of this piperidine family.
Graphene‐Modified Carbon Fiber Microelectrode for the Detection of Dopamine in Mice Hippocampus Tissue
Authors: Zhu Mingfang , Zeng Changqing , Ye Jianshan 
Published: March 2011

AbstractWe developed a novel graphene‐modified carbon fiber microelectrode (GCFME) to determine dopamine in mice hippocampus tissue. The electrochemical behavior of GCFME is characterized by potassium ferricyanide, dopamine (DA), ascorbic acid (AA) and uric acid (UA) by cyclic voltammetry (CV). Graphene makes a favorable electron transfer process for the oxidation of DA, AA, UA, and provides well‐resolved oxidative peaks of the three. The microsensor for DA shows good sensitivity and selectivity, with a linear range from 1.0×10−8 M to 1.0×10−4 M and a detection limit of 1.0×10−8 M. This graphene‐based microelectrode successfully monitored the release of dopamine in vitro.
Seawater scrubbing desulfurization: A model for SO2 absorption in fall‐down droplets
Authors: Caiazzo Giuseppe , Di Nardo Antonio , Langella Giuseppe , Scala Fabrizio 
Published: March 2011

AbstractAn unsteady model of SO2 absorption in fall‐down spherical seawater droplets is presented, focused on marine diesel engine exhaust gas scrubbing. The model evaluates the amount of sulfur dioxide absorbed by a single droplet, with given initial velocity, diameter, and alkalinity, falling counter‐flow with respect to the exhaust gas stream. Kinematics of the droplet, heat exchange, and evaporation has been considered, taking into account internal circulation. Neutralization of absorbed sulfur species in the droplet has been modeled with a global and fast reaction mechanism. Transport equations for species inside the droplet have been solved on a nonuniform computational grid, which is regenerated at every time step to account for droplet diameter reduction. The single‐droplet model has been incorporated in a simple scrubber plug‐flow model, to evaluate the desulfurization efficiency and the seawater supply rate under realistic marine engine exhaust gas desulfurization conditions. The influence of flue gas inlet temperature, flue gas velocity, initial droplet size, and velocity on the scrubbing process were investigated. Results of this model are valuable for judging the feasibility and operating costs of this SO2 scrubbing technique compared with alternative methods. © 2011 American Institute of Chemical Engineers Environ Prog, 2011
A study on the Kabachnik–Fields reaction of benzaldehyde, propylamine, and diethyl phosphite by in situ Fourier transform IR spectroscopy
Authors: Keglevich György , Fehérvári András , Csontos István 
Published: March 2011

AbstractThe phospha‐Mannich condensation of benzaldehyde, n‐propylamine, and diethyl phosphite carried out at 80°C in acetonitrile takes place via the imine (PhCNPr) intermediate as suggested by in situ FT‐IR spectroscopy. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:599–604, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20676
Flow perfusion culture of human mesenchymal stem cells on coralline hydroxyapatite scaffolds with various pore sizes
Authors: Bjerre Lea , Bünger Cody , Baatrup Anette , Kassem Moustapha , Mygind Tina 
Published: March 2011

AbstractBone grafts are widely used in orthopaedic reconstructive surgery, but harvesting of autologous grafts is limited due to donor site complications. Bone tissue engineering is a possible alternative source for substitutes, and to date, mainly small scaffold sizes have been evaluated. The aim of this study was to obtain a clinically relevant substitute size using a direct perfusion culture system. Human bone marrowderived mesenchymal stem cells were seeded on coralline hydroxyapatite scaffolds with 200 μm or 500 μm pores, and resulting constructs were cultured in a perfusion bioreactor or in static culture for up to 21 days and analysed for cell distribution and osteogenic differentiation using histological stainings, alkaline phosphatase activity assay, and real‐time RT‐PCR on bone markers. We found that the number of cells was higher during static culture at most time points and that the final number of cells was higher in 500 μm constructs as compared with 200 μm constructs. Alkaline phosphatase enzyme activity assays and real time RT‐PCR on seven osteogenic markers showed that differentiation occurred primarily and earlier in statically cultured constructs with 200 μm pores compared with 500 μm ones. Adhesion and proliferation of the cells was seen on both scaffold sizes, but the vitality and morphology of cells changed unfavorably during perfusion culture. In contrast to previous studies using spinner flask that show increased cellularity and osteogenic properties of cells when cultured dynamically, the perfusion culture in our study did not enhance the osteogenic properties of cell/scaffold constructs. The statically cultured constructs showed increasing cell numbers and abundant osteogenic differentiation probably because of weak initial cell adhesion due to the surface morphology of scaffolds. Our conclusion is that the specific scaffold surface microstructure and culturing system flow dynamics has a great impact on cell distribution and proliferation and on osteogenic differentiation, and the data presented warrant careful selection ofin vitroculture settings to meet the specific requirements of the scaffolds and cells, especially when natural biomaterials with varying morphology are used. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Fabrication and characterization of porous EH scaffolds and EH‐PEG bilayers
Authors: Falco Erin E. , Coates Emily E. , Li Erik , Roth J. Scott , Fisher John P. 
Published: March 2011

AbstractBiomaterials made from synthetic polymers are becoming more pervasive in the medical field. Synthetic polymers are particularly advantageous as their chemical and mechanical properties can be easily tailored to a specific application. This work characterizes polymer scaffolds derived from the cyclic acetal monomer 5‐ethyl‐5‐(hydroxymethyl)‐β,β‐dimethyl‐1,3‐dioxane‐2‐ethanol diacrylate (EHD). Both porous scaffolds and bilayer scaffolds based upon the EHD monomer were fabricated, and the resulting scaffolds' degradation and mechanical properties were studied. The results showed that by modifying the architecture of an EH scaffold, either by adding a porous network or a poly(ethylene glycol) (PEG) coating, the degradation and Young's modulus of the biomaterial can be significant altered. However, results also indicated that these architectural modifications can be accomplished without a significant loss in the flexural strength of the scaffold. Therefore, we suggest that porous EH scaffolds, and particularly porous EH‐PEG bilayers, may be especially useful in dynamic tissue environments due to their advantageous architectural and mechanical properties. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part A:, 2011.
Books Versus triangles
Authors: Mubayi Dhruv 
Published: March 2011

AbstractA book of size b in a graph is an edge that lies in b triangles. Consider a graph G with n vertices and ⌋n2/4⌋; + 1 edges. Rademacher proved that G contains at least ⌋n/2⌋; triangles, and several authors proved that G contains a book of size at least n/6. We prove the following “linear combination” of these two results. Suppose that and the maximum size of a book in G is less than αn/2. Then G contains at least

urn:x-wiley:03649024:jgt20607:equation:jgt20607-math-0002

triangles as n→Ȟ. This is asymptotically sharp. On the other hand, for every , there exists β>0 such that G contains at least βn3 triangles. It remains an open problem to determine the largest possible β in terms of α. Our short proof uses the triangle removal lemma, although there is another approach which avoids this. © 2011 Wiley Periodicals, Inc. J Graph Theory
Measuring state–business relations within developing countries: An application to Indian states
Authors: Calì Massimiliano , Mitra Siddhartha , Purohit Purnima 
Published: March 2011

AbstractEffective relations between states and business have been increasingly identified as an important institution for sustaining economic development. This paper constructs quantitative indices measuring the quality of state–business relations (SBRs) across Indian states in the 1985–2008 period. It represents the first effort to systematically characterise SBRs across sub‐national units within a country without resorting to subjective surveys. We discuss the possible sensitivity of the indices to minor and major definitional changes and examine the evolution of SBRs across Indian states and at the national level through the study of cross‐sectional and secular trends in these indices. The results suggest that SBRs have improved over time in all states barring Bihar. Rankings of states in terms of the SBR index show varying time trends—stable and high ranks for states like Andhra Pradesh, Karnataka, and Tamil Nadu, stable and low ranks for states like Uttar Pradesh and West Bengal, rapidly improving ranks for states like Haryana, Punjab and Rajasthan and swift deterioration in ranks for states like Bihar and Madhya Pradesh. Copyright © 2011 John Wiley & Sons, Ltd.