bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fluorescence‐based analysis of enzymes at the single‐molecule level
Authors: Blank Kerstin , De Cremer Gert , Hofkens Johan 
Published: February 2009

AbstractEnzymes, and proteins in general, consist of a dynamic ensemble of different conformations, which fluctuate around an average structure. Single‐molecule experiments are a powerful tool to obtain information about these conformations and their contributions to the catalytic reaction. In contrast to classical ensemble measurements, which average over the whole population, singlemolecule experiments are able to detect conformational heterogeneities, to identify transient or rare conformations, to follow the time series of conformational changes and to reveal parallel reaction pathways. A number of single‐molecule studies with enzymes have proven this potential showing that the activity of individual enzymes varies between different molecules and that the catalytic rate constants fluctuate over time. From a practical point of view this review focuses on fluorescence‐based methods that have been used to study enzymes at the single‐molecule level. Since the first proof‐of‐principle experiments a wide range of different methods have been developed over the last 10 years and the methodology now needs to be applied to answer questions of biological relevance, for example about conformational changes induced by allosteric effectors or mutations.
Research regarding the implementation of an interactive application for educational improvement of engineering drawing
Authors: Pando Cerra Pablo , Alvarez Peñin Pedro , Perez Morales Maximo , Higuera Garrido Alberto 
Published: February 2009

AbstractIn the current European university reform teacher‐based education is replaced by another form of teaching, which is more focused on the students. To facilitate this task, a self‐learning‐oriented application called AIMEC‐DT was developed. This article discusses, by means of an educational experience, the advantages of using these types of interactive tools adapted to achieve that goal. The results obtained allow us to conclude that their use can be a significant improvement in teaching in engineering. © 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 183–192, 2011
Gating Characteristics of Thermo‐Responsive Membranes with Grafted Linear and Crosslinked Poly(N‐isopropylacrylamide) Gates
Authors: Chen Y.‐C. , Xie R. , Yang M. , Li P.‐F. , Zhu X.‐L. , Chu L.‐Y. 
Published: February 2009

AbstractThermo‐responsive porous membranes with grafted linear and crosslinked poly(N‐isopropylacrylamide) (PNIPAM) gates are successfully prepared at temperatures above and below the lower critical solution temperature (LCST) of PNIPAM by using a plasma‐induced grafting polymerization method, and the effects of operation pressure and grafting temperature on the thermo‐responsive gating characteristics of the prepared membranes are investigated systematically. The fluxes of water through the grafted membranes increase simply with increasing the operation pressure no matter whether the environmental temperature is 40 °C or 25 °C. Under high operation pressure (e.g., higher than 0.14 MPa), the grafted linear PNIPAM gates deform to a certain extent, whereas the grafted crosslinked PNIPAM gates do not deform. For both membranes with grafted linear and crosslinked PNIPAM gates, the membranes prepared at 25 °C (below the LCST of PNIPAM) show larger thermo‐responsive gating coefficients than those prepared at 40 °C (above the LCST of PNIPAM), which results from different distributions of grafted PNIPAM gates in the membrane pores. When the PNIPAM gates are grafted at 25 °C, the grafted layer near the membrane surface is much thicker than that inside the membrane pores; on the other hand, when the PNIPAM gates are grafted at 40 °C, the grafted layer is homogeneously formed throughout the whole pore length. Both linear and crosslinked grafted PNIPAM gates in the membrane pores exhibit stable and repeatable thermo‐responsive “open‐close” switch performances under the operation pressure of 0.26 MPa. The results in this study provide valuable guidance for designing, fabricating, and operating thermo‐responsive gating membranes with desirable performances.
On‐line Statistical Process Monitoring and Fault Diagnosis in Batch Baker's Yeast Fermentation
Authors: Berber R. , Atasoy I. , Yuceer M. , Deniz G. 
Published: February 2009

AbstractThis study involves real‐time monitoring and fault diagnosis in batch baker's yeast fermentation. A specific Real Time Statistical Process Analysis and Control (RT‐SPAC) program was developed to monitor instantaneous reaction conditions. The air flow rate fed to the reactor, temperature, pH, and dissolved oxygen concentration in a laboratory‐size fermenter were monitored and recorded by means of on‐line sensors. Under control of the RT‐SPAC program, 22 batch baker's yeast fermentation operations were carried out. In the first 20 operations, an ordinary process was followed under previously defined nominal operating conditions. Historical data collected from these batches were then used for on‐line Dynamic Principal Component Analysis (DPCA) in the course of the following two batches. The last two batches were implemented such that some deliberate faults (in temperature and pH) were introduced during the operation. The results indicated that the software was capable of capturing the process faults, and furthermore the possible causes of these faults were identified by contribution plots.
Reactivities of the Prism‐Shaped Diamondoids [1(2)3]Tetramantane and [12312]Hexamantane (Cyclohexamantane)
Authors: Fokin Andrey A. , Tkachenko Boryslav A. , Fokina Natalie A. , Hausmann Heike , Serafin Michael , Dahl Jeremy E. P. , Carlson Robert M. K. , Schreiner Peter R. 
Published: February 2009

AbstractFunctionalized nanodiamonds: Various functional groups have been incorporated into the structures of the naturally occurring diamondoids [1(2)3]tetramantane and [12312]hexamantane (cyclohexamantane), which represent hydrogen‐terminated prism‐shaped nanodiamonds (see picture). The attachment points define the use of these diamond‐like molecules as geometric building blocks for a variety of applications.magnified imageVarious functional groups have been incorporated into the structures of the naturally occurring diamondoids [1(2)3]tetramantane and [12312]hexamantane (cyclohexamantane), which represent hydrogen‐terminated prism‐shaped nanodiamonds. The selectivities of the CH substitutions in [1(2)3]tetramantane depend on the reagent employed and give products substituted at either central (through bromination) or peripheral (through nitroxylation and photo‐oxidation) positions. The hydrogen‐coupled electron‐transfer mechanism of CH nitroxylation with the model electrophile NO2+⋅⋅⋅HNO3 was verified computationally at the B3PW91 and MP2 levels of theory by utilizing the 6‐31G(d) and cc‐pVDZ basis sets. The thermodynamically controlled nitroxylation/isomerization of [1(2)3]tetramantane allows the preparation of peripherally trisubstituted derivatives, which were transformed into tripod‐like nanodiamond building blocks. The bromination of cyclohexamantane selectively gives the 2‐bromo derivative, reproducing the chemical behavior of the {111} surface of the hydrogen‐terminated diamond.
Palladium‐Catalyzed Heck Reaction of Polyoxometalate‐Functionalised Aryl Iodides and Bromides with Olefins
Authors: Zhu Yulin , Wang Longsheng , Hao Jian , Yin Panchao , Zhang Jin , Li Qiang , Zhu Li , Wei Yongge 
Published: February 2009

AbstractOrganically derivatised polyoxometalate (POM) clusters containing bromo or iodo groups can undergo ligand‐free, Pd‐catalysed Heck carbon–carbon coupling reactions with alkenes, with bromomagnesium phenylamide as a base (see scheme). This protocol offers a new route to organic–inorganic hybrid molecular materials in which POM clusters are covalently bonded with organic conjugated segments.magnified image
Synthesis and Resolution of Planar–Chiral Ruthenium–Palladium Complexes with ECE′ Pincer Ligands
Authors: Bonnet Sylvestre , Li Jie , Siegler Maxime A. , von Chrzanowski Lars S. , Spek Anthony L. , van Koten Gerard , Klein Gebbink Robertus J. M. 
Published: February 2009

AbstractFeel the pinch! Planar–chiral, cationic, ruthenium–palladium complexes based on η6,η1‐coordinated ECE′ pincer ligands are synthesized as racemic mixtures by reacting ECE′–palladium complexes and [Ru(C5R5)(MeCN)3]+ arenophiles (R=H or Me). Chiral resolution of the cationic complexes was achieved by using the chiral counterion [Δ‐TRISPHAT]−, and solving the X‐ray crystal structure of one diastereoisomer (shown here).magnified image
A N,N′‐Dioxide–Copper(II) Complex as an Efficient Catalyst for the Enantioselective and Diastereoselective Mannich‐Type Reaction of Glycine Schiff Bases with Aldimines
Authors: Shang Deju , Liu Yanling , Zhou Xin , Liu Xiaohua , Feng Xiaoming 
Published: February 2009

AbstractMild mannered! A highly diastereo‐ and enantioselective Mannich‐type reaction of glycine Schiff base 1 has been developed by using the N,N′‐dioxide L‐CuII complex as a catalyst. Various optically active anti‐α,β‐diamino acid esters were obtained in good yields with up to 96:4 d.r. and 97 % ee. This straightforward method features a low catalyst loading and mild reaction conditions.magnified image
ChemInform Abstract: Efficient Copper‐Catalyzed Coupling of 2‐Haloacetanilides with Phosphine Oxides and Phosphites under Mild Conditions.
Authors: Jiang Deshou , Jiang Qun , Fu Hua , Jiang Yuyang , Zhao Yufen 
Published: February 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Isolation, Structure Determination, and Synthesis of Galaxamide, a Rare Cytotoxic Cyclic Pentapeptide from a Marine Algae Galaxaura filamentosa.
Authors: Xu Wen‐Jie , Liao Xiao‐Jian , Xu Shi‐Hai , Diao Jian‐Zhong , Du Bin , Zhou Xu‐Long , Pan Shan‐Shan 
Published: February 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract: Cebulactams A1 and A2, New Macrolactams Isolated from Saccharopolyspora cebuensis, the First Obligate Marine Strain of the Genus Saccharopolyspora.
Authors: Pimentel‐Elardo Sheila Marie , Gulder Tobias A. M. , Hentschel Ute , Bringmann Gerhard 
Published: February 2009

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
Lanthanide (III) salt complexes: Arrayed acid‐base networks for enantioselective catalysis. The nitroaldol reaction upon aldehydes and trifluoromethylketones
Authors: Saá José M. , Tur Fernando , González José 
Published: February 2009

AbstractShelf stable, chiral‐at‐metal, D3 symmetric, 3:1 complexes of lanthanide (III) triflate salts are easily available by complexation with binolam (3,3′‐diethylaminomethyl‐2,2′‐dihydroxy‐1,1′‐dinaphthalene) 1 or binolamo (3,3′‐diethylaminooxymethyl‐2,2′‐dihydroxy‐1,1′‐dinaphthalene) 2 ligands. The resulting compounds 3Ln and 4Ln are isostructural, as demonstrated by their spectroscopic data, and possess an arrayed acid‐base LABABB network. Complexes are kinetically labile, and in solution undergo hydrolysis by water. The lanthanum complex derived from binolam, i.e., (Δ,S,S,S)‐ (binolam)3.la(OTf)33La was found to be the most active catalyst in promoting direct nitroaldol reactions upon aldehydes and trifluoromethyl ketones, thereby giving rise to secondary nitroalcohols and tertiary α‐trifluoromethyl‐β‐nitroalcohols, respectively, with high ee in both cases. Enantiomerically enriched tertiary nitroalcohols were easily reduced to the corresponding aminoalcohols having a quaternary asymmetric carbon without loss of enantiomeric purity. Chirality 2009. © 2009 Wiley‐Liss, Inc.
Enantiopure cyclic O‐substituted phenylphosphonothioic acid: Synthesis and chirality‐recognition ability
Authors: Ribeiro Nigel , Kobayashi Yuka , Maeda Jin , Saigo Kazuhiko 
Published: February 2009

AbstractAs a new acidic selector (resolving agent), we synthesized an enantiopure O‐alkyl phenylphosphonothioic acid with a seven‐membered ring ((R)‐5), which was designed on the basis of the results for the enantioseparation of 1‐arylethylamine derivatives with acyclic O‐ethyl phenylphosphonothioic acid (I). The phosphonothioic acid (R)‐5 showed unique chirality‐recognition ability in the enantioseparation of 1‐naphthylethylamine derivatives, aliphatic secondary amines, and amino alcohols; the ability was complementary to that of I. The X‐ray crystallographic analyses of the less‐ and more‐soluble diastereomeric salts showed that hydrogen‐bonding networks in the salt crystals are 21‐column‐type with a single exception which is cluster‐type. In the cases of the 21‐column‐type crystals, stability of the crystals is firstly governed by hydrogen bonds to form a 21‐column and secondly determined by intra‐columnar T‐shaped CH/π interaction(s), intra‐columnar hydrogen bond(s), inter‐columnar van der Waals interaction and/or inter‐columnar T‐shaped CH/π interaction(s). In contrast, the cluster‐type salt crystal is stabilized by the assistance of inter‐cluster T‐shaped CH/π and van der Waals interactions. To realize still more numbers of intra‐ and inter‐columnar and ‐cluster T‐shaped CH/π interactions, the seven‐membered ring of (R)‐5 plays a considerable role. Chirality 23:438–448, 2011. © 2009 Wiley‐Liss, Inc.
Effects of solvent on chiral and enantiomeric separation of Koga bases using derivatized amylose chiral stationary phase
Authors: Guo Hong‐Xun , Wu Steven , Nadeau Kelly , Moniz George A. , Caille Sebastian 
Published: February 2009

AbstractThe separation of R,R‐, S,S‐, and meso‐Koga bases on derivatized amylose chiral stationary phases (CSP) has been studied using different alcohol and alcohol‐hexane mixtures as eluant. Straight‐chain and branched alcohols with carbon numbers from one to four were investigated. The carbon number and geometry of the alcohol impacts the separation of Koga bases. The optimal separations were obtained using a mixture of methanol with linear or branched alcohol. Also, the elution order of meso‐ and R,R‐Koga base was switched as content of branched alcohol increases in cosolvent. The study of acidic and basic additive effects demonstrated that maintaining analytes in the free base state is crucial in order to achieve retention and separation. TEA alone or TEA and TFA mixture were used in the studies. Chirality 2010. © 2009 Wiley‐Liss, Inc.
A reformulation of the Lesaint–Raviart discontinuous Galerkin method for advection equations
Authors: Fortin M. , Fortin A. , Benmoussa K. , Tibirna C. 
Published: February 2009

AbstractThe Lesaint–Raviart method was introduced in 1974 for the numerical solution of the neutron transport equation. It is probably the first discontinuous Galerkin (DG) method ever introduced. In this paper, we propose an equivalent formulation of this DG‐type method for advection problems that can be easily implemented into existing finite element codes. The proposed formulation also presents some advantages in domains where there is no inflow boundary such as those encountered in the tire industry. Copyright © 2009 John Wiley & Sons, Ltd.
ONIOM Study of Isomerization Reactions of Aromatic Hydrocarbons in Acidic Mordenite Zeolite
Authors: Yang Jing 
Published: February 2009

AbstractTwo different mechanisms: Shift 1,2‐isomerization and isomerization via the disproportionation reaction are investigated for aromatic hydrocarbons over acidic mordenite zeolite by using our own n‐layered integrated molecular orbital and molecular mechanics (ONIOM) scheme. The picture shows a schematic energy profile for the isomerization of toluene catalyzed by acidic mordenite.magnified imageThe geometrical structures and energies of isomerization reactions of aromatic hydrocarbons catalyzed by the 128T cluster model of acidic mordenite zeolite are studied by using our own n‐layered integrated molecular orbital and molecular mechanics (ONIOM) scheme. The aromatic hydrocarbons investigated are toluene, xylenes, and trimethylbenzenes. Two proposed intramolecular reaction mechanisms, that is, shift 1,2‐isomerization and isomerization via the disproportionation reaction, are studied and discussed in detail. Both of the mechanisms firstly proceed by protonation of aromatic hydrocarbons to form the aromatic‐based carbenium ions. Attempts to determine the prevailing reaction mechanism of the isomerization are evaluated. In most cases, the isomerization reactivity sequence is: trimethylbenzenes>xylenes>toluene. The conclusions obtained using the ONIOM scheme agree with the available periodic DFT and experimental results on acidic mordenite zeolite.
Biosurfactants from Urban Green Waste
Authors: Montoneri Enzo , Boffa Vittorio , Savarino Piero , Perrone Daniele G. , Musso Giorgia , Mendichi Raniero , Chierotti Michele R. , Gobetto Roberto 
Published: February 2009

AbstractFrom waste came forth surfactants: Humic acid like substances isolated from 0–60 day‐old compost display excellent surface activity and solvent properties. These biosurfactants were used to solubilize a dye in water below and above their critical micellar concentration. The biosurfactant unimers appear to have higher dye‐solubilizing power than the corresponding micelles.magnified imageHumic acid like substances isolated from compost show potential as chemical auxiliaries. In the present study, three surfactant samples were obtained from green waste composted for 0–60 days to assess aging effects of the source on the properties of the products. The surface activity, dye solubility enhancement, and chemical nature of these substances were compared. No differences in performance were established among the samples. They lower water surface tension and enhance the dye solubility upon increasing their concentration. However, the ratio of soluble dye to added surfactant is higher in the premicellar than in the postmicellar concentration region. Structural investigations indicated the humic acid like substances to be amphiphiles with molecular weights in the range of 1–3×105 g mol−1. The surfactant samples were also compared to sodium dodecylbenzenesulfonate, polyacrylic acid, and soil and water humic substances. The results encourage the application of compost as a source of low‐cost biosurfactant.
Plasma‐Enhanced Atomic Layer Deposition of Semiconductor Grade ZnO Using Dimethyl Zinc
Authors: Rowlette Pieter C. , Allen Cary G. , Bromley Olivia B. , Dubetz Amy E. , Wolden Colin A. 
Published: February 2009

AbstractZinc oxide films are deposited over the temperature range 25–120 °C by plasma‐enhanced atomic layer deposition (PEALD) using dimethyl zinc (DMZ, Zn(CH3)2) as the metal precursor. DMZ is unreactive with molecular oxygen under process conditions, facilitating its utility for PEALD. The deposition rate is independent of plasma exposure (1–5 s) and saturates for DMZ exposures ≥75 mTorr s. The saturated growth per cycle increases from 1.6 to 2.9 Å per cycle as the temperature is increased from 25 to 85 °C, and remains constant in the range 85–120 °C. Over the narrow range explored, substrate temperature has a dramatic impact on film structure and properties. Polycrystalline films with a (100) texture are obtained at room temperature, with the preferred orientation evolving to the (002) direction as the temperature increases. The electrical resistivity decreases exponentially from 270 at room temperature to values of ∼5 Ω cm within the ALD window. Compositional analysis shows that films at low temperature are contaminated by carbon and hydroxyl impurities, however these defects are attenuated with temperature and not detected in films deposited within the ALD window. Room temperature photoluminescence is dominated by strong emission from ZnO defects in most films, however these signals are attenuated and strong band edge emission is observed for films deposited at 120 °C.
Imprint cytology of pancreatoblastoma: A case report and review of the literature
Authors: Sahu Kausalya Kumari , Rau Aarathi R. , Bhat Narayana , Kini Jyoti R. , Mathai Alka Mary 
Published: February 2009

AbstractPancreatoblastoma is a rare tumor with ∼60 cases described in the English literature and only five case reports illustrating the cytologic findings, four by fine‐needle aspiration cytology and one by imprint cytology. We herein report the sixth case diagnosed by imprint cytology. Both the cytologic and histopathologic literatures are reviewed, and the pathologic variations observed in our case are also documented. Diagn. Cytopathol. 2009. © 2009 Wiley‐Liss, Inc.
Synthesis, Characterization, Thermodynamic and Kinetic Properties of a New Series of Dinuclear PtII Complexes
Authors: Ertürk Hakan , Puchta Ralph , van Eldik Rudi 
Published: February 2009

AbstractThe dinuclear PtII complexes bis{[(1R,2R)‐(–)‐1,2‐diaminocyclohexane]chloroplatinum(II)}(μ‐1,8‐octanediamine), bis{[(1R,2R)‐(–)‐1,2‐diaminocyclohexane]chloroplatinum(II)}(μ‐1,10‐decanediamine) and bis{[(1R,2R)‐(–)‐1,2‐diaminocyclohexane]chloroplatin(II)}[μ‐1,4‐bis(3‐pyridyl)buta‐1,3‐diyne] were synthesized. Acid‐base titrations and concentration and temperature dependent measurements of the reactions with chloride and thiourea were performed to study the influence of the nature of the bridging ligand on the thermodynamic and kinetic properties of the complexes. The reactions with chloride and thiourea were followed under pseudo‐first‐order conditions by stopped‐flow and UV/Vis spectrophotometry. The results indicate that the bridging ligand has an influence on the reactivity and stability of the complexes towards nucleophiles as well as on possible electronic interactions between the two PtII centres. The experimental results are discussed in reference to structures obtained by DFT (BP86/LACVP*) calculations. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Species identification in mammals from mixed biological samples based on mitochondrial DNA control region length polymorphism
Authors: Pun Ka‐Man , Albrecht Catherine , Castella Vincent , Fumagalli Luca 
Published: February 2009

AbstractThe ability to identify the species origin of an unknown biological sample is relevant in the fields of human and wildlife forensics. However, the detection of several species mixed in the same sample still remains a challenge. We developed and tested a new approach for mammal DNA identification in mixtures of two or three species, based on the analysis of mitochondrial DNA control region interspecific length polymorphism followed by direct sequencing. Contrary to other published methods dealing with species mixtures, our protocol requires a single universal primer pair and is not based on a pre‐defined panel of species. Amplicons can be separated either on agarose gels or using CE. The advantages and limitations of the assay are discussed under different conditions, such as variable template concentration, amplicon sizes and size difference among the amplicons present in the mixture. For the first time, this protocol provides a simple, reliable and flexible method for simultaneous identification of multiple mammalian species from mixtures, without any prior knowledge of the species involved.