bluuebunny/crossref_metadata_2025_split huggingface dataset:
An Efficient Route to Selective Bio‐oxidation Catalysts: an Iterative Approach Comprising Modeling, Diversification, and Screening, Based on CYP102A1
Authors: Seifert Alexander , Antonovici Mihaela , Hauer Bernhard , Pleiss Jürgen 
Published: May 2011

AbstractPerillyl alcohol is the terminal hydroxylation product of the cheap and readily available terpene, limonene. It has high potential as an anti‐tumor substance, but is of limited availability. In principle, cytochrome P450 monooxygenases, such as the self‐sufficient CYP102A1, are promising catalysts for the oxidation of limonene or other inert hydrocarbons. The wild‐type enzyme converts (4R)‐limonene to four different oxidation products; however, terminal hydroxylation at the allylic C7 is not observed. Here we describe a generic strategy to engineer this widely used enzyme to hydroxylate exclusively the exposed, but chemically less reactive, primary C7 in the presence of other reactive positions. The approach presented here turns CYP102A1 into a highly selective catalyst with a shifted product spectra by successive rounds of modeling, the design of small focused libraries, and screening. In the first round a minimal CYP102A1 mutant library was rationally designed. It contained variants with improved or strongly shifted regio‐, stereo‐ and chemoselectivity, compared to wild‐type. From this library the variant with the highest perillyl alcohol ratio was fine‐tuned by two additional rounds of molecular modeling, diversification, and screening. In total only 29 variants needed to be screened to identify the triple mutant A264V/A238V/L437F that converts (4R)‐limonene to perillyl alcohol with a selectivity of 97 %. Focusing mutagenesis on a small number of relevant positions identified by computational approaches is the key for efficient screening for enzyme selectivity.
A Facile and Specific Approach to New Liquid Chromatography Adsorbents Obtained by Ionic Self‐Assembly
Authors: Qiu Hongdeng , Mallik Abul K. , Takafuji Makoto , Ihara Hirotaka 
Published: May 2011

AbstractA new ionic‐liquid monomer, 1‐vinyl‐3‐octadecylimidazolium bromide ([C18VIm]Br), was prepared and polymerized on porous silica particles by means of a surface‐initiated radical chain‐transfer reaction. Further modification for functionalization was performed through the exchange of counteranions from bromide to methyl orange (MO). Two new silica–poly(octadecylimidazolium) (Sil‐PImC18) hybrid materials (Sil‐PImC18‐Br and Sil‐PImC18‐MO) were synthesized and characterized by elemental analysis, thermogravimetric analysis, diffuse reflectance infrared Fourier transform spectroscopy (DRIFT), and solid‐state 13C CP/MAS NMR spectroscopy. Sil‐PImC18‐MO presented ultra‐high shape selectivity for constrained isomers of polycyclic aromatic hydrocarbons (PAHs) both in reversed‐ and normal‐phase HPLC when used as the stationary phase. Fundamental aspects of the molecular shape selectivity were evaluated by using Standard Reference Material (SRM) 869b; the column selectivity test mixture for liquid chromatography. The impact of this phase was also demonstrated by the separation of SRM 1647e (16 priority pollutant PAHs) and several steroid isomers. Enhanced selectivity could be explained by the highly oriented arrangement between the octadecylimidazolium chain and a rigid segment of MO. These findings may open a new window of research for the design of materials used in chromatographic supports, solid extraction, catalysis, and electrolytes by simple modifications of the counterions in the poly(ionic liquid) analogous phase.
Reverse‐Flow Adsorption for Process‐Integrated Recycling of Homogeneous Transition‐Metal Catalysts
Authors: Marras Fabrizio , van Leeuwen Piet W. N. M. , Reek Joost N. H. 
Published: May 2011

AbstractSupramolecular strategies, based on hydrogen bonds and ionic interactions, were investigated as tools for the recovery and recycling of homogeneous transition‐metal catalysts by using reverse‐flow adsorption (RFA) technology. The association (in solution) and adsorption (on support) of new functionalized host materials and phosphine guest ligands, functionalized with the complementary binding motifs, were fine‐tuned for the application of these materials in a RFA reactor. The RFA technology for process‐integrated recycling of homogeneous catalysts using these tailor‐made phosphine ligands and silica‐supported host materials resulted in a stable, semicontinuous catalytic system. Rhodium‐catalyzed asymmetric hydrogenation of methyl acetamidoacrylate and asymmetric hydrosilylation of acetophenone were studied as test reactions. Depending on the catalytic process the metal complex could be recycled several times without significant loss in conversion.
Pyrrolo[3,2‐h]quinazolines as Photochemotherapeutic Agents
Authors: Barraja Paola , Caracausi Libero , Diana Patrizia , Montalbano Alessandra , Carbone Anna , Salvador Alessia , Brun Paola , Castagliuolo Ignazio , Tisi Silvia , Dall'Acqua Francesco , Vedaldi Daniela , Cirrincione Girolamo 
Published: May 2011

AbstractHeteroanalogues of angelicin, pyrrolo[3,2‐h]quinazolines, were synthesized with the aim of obtaining new potent photochemotherapeutic agents. Many derivatives caused a significant decrease in cell proliferation in several human tumor cell lines after irradiation with UVA light (GI50=15.2–0.2 μM). Their phototoxicity effected apoptosis in Jurkat cells with the involvement of mitochondria (as determined by the loss of mitochondrial membrane potential and production of reactive oxygen species) and lysosomes. The phototoxicity of these compounds could be explained by lipid peroxidation.
Low temperature pulsed electron deposition and characterization of ZnS films for application in solar cells
Authors: Zanettini S. , Bissoli F. , Nasi L. , Ranzieri P. , Gilioli E. 
Published: May 2011

AbstractZinc Sulphide films were grown by pulsed electron deposition (PED) from room temperature to 350 °C to investigate the possibility of its application in solar cells, in particular as an alternative buffer layer deposited at low temperature. The films were characterized by X‐ray diffraction, TEM, AFM, optical absorption and electrical measurements. ZnS films display crystalline structure and columnar growth at room temperature on amorphous substrate; the crystallization improves with the substrate temperature and is predominantly related to the cubic (111) orientation, while the thicker films show coexistence of hexagonal and cubic structures. All the samples have transparencies exceeding 70% in the range 400‐1000 nm, energy band gap between 3.25 and 3.65 eV increasing with temperature and resistivity in the range of 104‐106 Ωcm. The optimization of the growth rate as a function of the growth parameters (substrate temperature and electron gun voltage) is also discussed. The reported results indicate that ZnS might be a suitable material for photovoltaic applications, specifically in process requiring low deposition temperature. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tracing of islet graft survival by way of in vivo fluorescence imaging
Authors: Kahraman Sevim , Dirice Ercument , Hapil Fatma Z. , Ertosun Mustafa G. , Ozturk Saffet , Griffith Thomas S. , Sanlioglu Salih , Sanlioglu Ahter D. 
Published: May 2011

AbstractBackgroundTo increase the success rate in xenogeneic islet transplantation, proper assessment of graft mass is required following transplantation. For this reason, we aimed to develop a suitable fluorescence imaging system to monitor islet xenograft survival in diabetic mice.MethodsAdenovirus vector encoding enhanced green fluorescent protein‐transduced rat pancreatic islets were transplanted under the renal capsule of streptozotocin‐induced diabetic mice and the fluorescence signal was quantified over time using a cooled charge‐coupled device. Non‐fasting blood glucose levels were recorded during the same period. Insulin release from transduced and control islets was detected via enzyme‐linked immunosorbent assay.ResultsAdenovirus vector encoding enhanced green fluorescent protein infection did not alter the function or survival of pancreatic islets post transduction. A direct correlation was found between the number of islets (250–750) transplanted under the kidney capsule and the blood glucose recovery.ConclusionsFluorescence imaging appears to be a useful tool for quantitative assessment of islet cell viability post transplantation and could permit earlier detection of graft rejection. Copyright © 2011 John Wiley & Sons, Ltd.
Benefits of a simple glycaemic protocol in an orthopaedic surgery ward: a randomized prospective study
Authors: Schroeder Josh E. , Liebergall M. , Raz I. , Egleston R. , Ben Sussan G. , Peyser A. , Eldor R. 
Published: May 2011

AbstractBackgroundHyperglycaemia and diabetes mellitus are common in patients hospitalized in the orthopaedic surgery ward. However, glycaemic control obtained during hospitalization is often suboptimal. No method for achieving adequate glycaemic control in this population has been validated in an in‐hospital setting.InterventionAn intervention including an intensive subcutaneous insulin protocol in the orthopaedic department.MethodsAll diabetic patients admitted to the Department of Orthopaedic Surgery were prospectively randomized during a 6‐month period. One group (n = 30) received standard care with sliding scale insulin and the other group (n = 35) received the intervention protocol. During the intervention period, the staff was briefed on the importance of glucose monitoring and control. An intensive multiple‐injection protocol consisting of four daily regular/neutral protamine hagedorn (NPH) insulin injections was initiated in diabetic patients. The programme was followed up by a consulting diabetologist.ResultsMean blood glucose levels throughout the hospitalization were 161.48 ± 3.8 mg/dL in the intervention group versus 175.29 ± 2.3 mg/dL in the control group (p < 0.0005). Hospitalization was shorter by 2 days in the intervention group (p < 0.05). The number of severe hyperglycaemic events (blood glucose level above 400 mg%) was significantly lower (p < 0.05) in the intervention group. There was no significant difference in the number of hypoglycaemic events.ConclusionsThe suggested four‐step intervention regimen improved glycaemic control of hospitalized patients in the orthopaedic department and simplified the ‘in‐house’ treatment of the diabetic patient. Hospital stays were reduced on average by two days (p < 0.05). Copyright © 2011 John Wiley & Sons, Ltd.
Prevalence, risk factors and complications associated with type 2 diabetes in migrant South Asians
Authors: Garduño‐Diaz Sara D. , Khokhar Santosh 
Published: May 2011

AbstractIt is estimated that type 2 diabetes (T2D) currently affects about 246 million people worldwide, with South Asians, especially Indians, having both the largest number of cases and the fastest growing prevalence. South Asian ethnicity has been identified as a major risk factor for the development of T2D with central adiposity, insulin resistance and an unfavourable lipid profile being identified as predominant signals of alarm. Leading databases, including Web of Science, Medline, PubMed and Science Direct, were consulted and manual searches were conducted for cited references in leading diabetes‐related journals. In all, 152 articles were included for the final assessment reported in this review. Genetic predisposition, central adiposity and unfavourable lifestyle, including physical inactivity and an unhealthy diet, were associated with the prevalence of T2D in migrant South Asians. ‘Westernization’, acculturation, socio‐economic factors and lack of knowledge about the disease have also been identified as contributors to the development of T2D in this population. Higher prevalence of T2D in migrant South Asians may not be entirely attributed to genetic predisposition; hence, ethnicity and associated modifiable risk factors need further investigation. Preventive measures and appropriate interventions are currently limited by the lack of ethnic‐specific cut‐off points for anthropometric and biological markers, as well as by the absence of reliable methods for dietary and physical activity assessment. This article describes the prevalence rate, risk factors and complications associated with T2D in migrant South Asians living in different countries. Copyright © 2011 John Wiley & Sons, Ltd.
NKG2D performs two functions in invariant NKT cells: Direct TCR‐independent activation of NK‐like cytolysis and co‐stimulation of activation by CD1d
Authors: Kuylenstierna Carlotta , Björkström Niklas K. , Andersson Sofia K. , Sahlström Peter , Bosnjak Lidija , Paquin‐Proulx Dominic , Malmberg Karl‐Johan , Ljunggren Hans‐Gustaf , Moll Markus , Sandberg Johan K. 
Published: May 2011

AbstractInvariant NKT cells are important in the activation and regulation of immune responses. They can also function as CD1d‐restricted killer cells. However, the role of activating innate NK‐cell receptors expressed on NKT cells in triggering cytolytic function is poorly characterized. Here, we initially confirmed that the cellular stress‐ligand receptor NKG2D is expressed on CD4− NKT cells, whereas most CD4+ NKT cells lack this receptor. Interestingly, NKG2D+ NKT cells frequently expressed perforin, and both NKG2D and perforin localized at the site of contact with NKG2D ligand‐expressing target cells. CD4− NKT cells degranulated in response to NKG2D engagement in a redirected activation assay independent of stimulation via their invariant TCR. NKT cells killed P815 cells coated with anti‐NKG2D mAb and CD1d‐negative K562 tumor target cells in an NKG2D‐dependent manner. Furthermore, NKG2D engagement co‐stimulated TCR‐mediated NKT‐cell activation in response to endogenous CD1d‐presented ligands or suboptimal levels of anti‐CD3 triggering. These data indicate that the CD4− subset of human NKT cells can mediate direct lysis of target cells via NKG2D engagement independent of CD1d, and that NKG2D also functions as a co‐stimulatory receptor in these cells. NKG2D thus plays both a direct and a co‐stimulatory role in the activation of NKT cells.
Selection of T‐cell receptors with a recurrent CDR3β peptide‐contact motif within the repertoire of alloreactive CD8+ T cells
Authors: Scifo Caroline , Mekaelian Laura , Munyazesa Elisaphane , Schmitt‐Verhulst Anne‐Marie , Guimezanes Annick 
Published: May 2011

AbstractPeptide/MHC complexes recognized by alloreactive T lymphocytes (TLs) have been identified, but their contribution to in vivo allo‐rejection is not known. We previously characterized the peptide pBM1, highly represented among endogenous H‐2Kb (Kb)‐associated peptides and critically required to induce full activation of H‐2k monoclonal CD8+ TLs expressing the cognate TCR‐BM3.3. Here, we asked whether a pBM1/Kb‐specific TL subset could be detected within a polyclonal TL population rejecting allogeneic cells in vivo. We show that the proportion of pBM1/Kb‐binding CD8+ TLs increased from <0.04% in naïve mice to 3% of activated CD44+ CD8+ TLs in H‐2k mice rejecting Kb‐expressing cells. Among these, TCR‐Vβ2 usage was greatly enriched, and 75% of them shared a TCR‐Vβ2 CDR3β motif with the prototype TCR‐BM3.3. Fewer than 5% of Kb‐reactive CD44+ CD8+ TLs not binding pBM1/Kb displayed this CDR3β motif. We found that the recurrent CDR3β motif of pBM1/Kb‐binding TLs was assembled from distinct V/D/J recombination events, suggesting that it is recruited upon immunization for its optimal TCR‐peptide/MHC fit. Thus, a CDR3β motif generated by a process akin to “convergent recombination” accounts for a sizable fraction of the alloreactive anti‐Kb TCR repertoire.
Expeditious Construction of Spiro‐Pyrrolidines by an Autocatalytic One‐Pot, Five‐Component, 1,3‐Dipolar Cycloaddition of in situ Generated Azomethine Ylides and Olefinic Dipolarophiles
Authors: Li Ming , Gong Fu‐Meng , Wen Li‐Rong , Li Zhao‐Rui 
Published: May 2011

AbstractTwo series of previously unknown spiro‐pyrrolidine derivatives were prepared by a five‐component reaction that employed ninhydrin, 1,2‐phenylenediamine, sarcosine, aldehydes, and malononitrile or cyanoacetic ester in a solvothermal synthesis. This is the first report of an autocatalytic five‐component reaction involving a classical Huisgen reaction, in which the dipole – an azomethine ylide – and the dipolarophile were simultaneously generated in situ. The 1,3‐dipolar cycloaddition reaction was found to proceed in a highly regio‐ and diastereoselective manner. The methodology for the preparation of the spiro‐pyrrolidines could be an ideal tool for green chemistry and the synthesis of alkaloids.
A Tandem Isomerization–Mannich Reaction for the Enantioselective Synthesis of β‐Amino Ketones and β‐Amino Alcohols with Applications as Key Intermediates for ent‐Nikkomycins and ent‐Funebrine
Authors: Cao Hai Thuong , Roisnel Thierry , Valleix Alain , Grée René 
Published: May 2011

Abstractβ‐Amino ketones, with a primary amino group, are easily obtained in good yields and excellent enantioselectivities through a short sequence that involves, as a key step, a tandem isomerization–Mannich reaction from allylic alcohols with N‐tert‐butanesulfinimines. This method was used for the enantioselective synthesis of corresponding β‐amino alcohols and also for key intermediates in the preparation of ent‐nikkomycins or ent‐funebrine.
A Practical, One‐Pot Multicomponent Synthesis of α‐Amidosulfides and Their Application as Latent N‐Acylimines in the Friedel–Crafts Reaction
Authors: George Nicolas , Bekkaye Mathieu , Masson Géraldine , Zhu Jieping 
Published: May 2011

AbstractA novel one‐pot, three‐component synthesis of N‐acyl or N‐carbamoyl‐α‐amidosulfides 4 is described. The three‐component reaction of aldehydes 1, primary carbamates (or amides) 2 and phenylsulfinic acid (6a) afforded α‐amidosulfones 7, which after addition of sodium thiolate were in situ transformed into stable α‐amidosulfides 4 in good to excellent yields. We demonstrated that silver salts or Brønsted acids were able to promote the formation of aliphatic and aromatic N‐acylimines from 4 in quantitative yield under mild conditions. The phosphoric acid catalyzed Friedel–Crafts alkylation of 3‐substituted indoles with α‐amidosulfides 4 leading to 2,3‐disubstitued indoles was also documented.
Fabrication of Au‐Nanoparticle/TiO2‐Nanotubes Electrodes Using Electrochemical Methods and Their Application for Electrocatalytic Oxidation of Hydroquinone
Authors: Hosseini Mir Ghasem , Momeni Mohamad Mohsen , Faraji Masoud 
Published: May 2011

AbstractGold nanoparticle (Au‐NPs)‐Titanium oxide nanotube (TiO2‐NTs) electrodes are prepared by using galvanic deposition of gold nanoparticles on TiO2‐NTs electrodes as support. Scanning electron microscopy and energy‐dispersive X‐ray spectroscopy results indicate that nanotubular TiO2 layers consist of individual tubes of about 60–90 nm diameters and gold nanoparticles are well‐dispersed on the surface of TiO2‐NTs support. The electrooxidation of hydroquinone of Au‐NPs/TiO2‐NTs electrodes is investigated by different electrochemical methods. Au‐NPs/TiO2‐NTs electrode can be used repeatedly and exhibits stable electrocatalytic activity for the hydroquinone oxidation. Also, determination of hydroquinone in skin cream using this electrode was evaluated. Results were found to be satisfactory and no matrix effects are observed during the determination of hydroquinone content of the “skin cream” samples.
A Combination Bismuth Bulk Electrode and Its Use in Adsorptive Constant‐Current Stripping Chronopotentiometry for Iron Using Solochrome Violet RS
Authors: Pimrote Wachirawan , Ratana‐Ohpas Roongroje , Renman Lars 
Published: May 2011

AbstractA new combination bismuth bulk electrode allowing potentiostatic control to be maintained in a suspended sample drop is described. The electrode was tested by adsorptive constant‐current stripping chronopotentiometry for iron(III) using Solochrome Violet RS. Optimum conditions were similar to those established with mercury‐based electrodes. With an electropolishing scheme, a reproducibility better than 2 % (n=54) was attainable. The limit of detection was 0.6 µg L−1 in deoxygenated samples. A partial least squares calibration gave a result of 972±78 µg L−1 (95 %, n=5) for a 1000±5 µg L−1 iron reference solution.
Extension of the Adaptive Huber Method for Solving Integral Equations Occurring in Electroanalysis, onto Kernel Function Representing Fractional Diffusion
Authors: Bieniasz Lesław K. 
Published: May 2011

AbstractElectroanalytical transient experiments performed under conditions of anomalous diffusion have recently attracted some attention. In order to enable automatic simulation of such experiments in the framework of the formalism of integral equations, the adaptive Huber method, recently elaborated by the present author, is extended onto integral transformation kernel function K(t,τ)=(t−τ)α/2−1 (where 0<α≤1), representing fractional diffusion. The extended method is tested on a model integral equation describing cyclic voltammetry for a reversible charge transfer reaction. The performance of the method is found similar to the case of ordinary diffusion.
Graphite Electrode Coated with a 7,16‐Dibenzyl‐1,4,10,13‐tetraoxa‐7,16‐diazacyclooctadecane‐Multiwalled Carbon Nanotube Composite as Sensor For Detection of Samarium
Authors: Agrahari Sunil K. , Srivastava Ashwini K. 
Published: May 2011

AbstractA composite multiwalled carbon nanotube polyvinyl chloride electrode based on 7,16‐dibenzyl‐1,4,10,13‐tetraoxa‐7,16‐diazacyclooctadecane (DBDA18C6) as Sm3+ ionophore is reported. This potentiometric sensor showed a wide linear working range, 1×10−2–1×10−8 M, Nernstian slope, 20.2±0.48 mV per decade and a limit of detection, 6.3±0.36×10−9 M. It works in the pH range 2.5–8.5 and shows a good selectivity over a number of metal ions. It has been found suitable for the analysis of ores and industrial effluents. The electrode surface is characterized by FRA and AFM.
Nanobioelectroanalysis Based on Carbon/Inorganic Hybrid Nanoarchitectures
Authors: Campuzano Susana , Wang Joseph 
Published: May 2011

AbstractThe emergence of nanotechnology has opened new horizons for electrochemical biosensors. This review highlights new concepts for electrochemical biosensors based on different carbon/inorganic hybrid nanoarchitectures. Particular attention will be given to hybrid nanostructures involving 1‐ or 2‐dimensional carbon nanotubes or graphene along with inorganic nanoparticles (gold, platinum, quantum dot (QD), metal oxide). Latest advances (from 2007 onwards) in electrochemical biosensors based on such hybrids of carbon/inorganic‐nanomaterial heterostructures are discussed and illustrated in connection to enzyme electrodes for blood glucose or immunoassays of cancer markers. Several strategies for using carbon/inorganic nanohybrids in such bioaffinity and biocatalytic sensing are described, including the use of hybrid nanostructures for tagging or modifying electrode transducers, use of inorganic nanomaterials as surface modifiers along with carbon nanomaterial label carriers, and carbon nanostructure‐based electrode transducers along with inorganic amplification tags. The implications of these nanoscale bioconjugated hybrid materials on the development of modern electrochemical biosensors are discussed along with future prospects and challenges.