bluuebunny/crossref_metadata_2025 huggingface dataset:
Synthesis and evaluation of chitosan‐vitamin C complexes
Authors: Xiaolin Tian , Dafeng Tian , Zhongyan Wang , Fengkui Mo
Published: July 2009

Chitosan (CS) is a biocompatible, biodegradable, and nontoxic polysaccharide polymer. It dissolves in water only if the pH is lower than 6.5. To extend its range of application, many water‐soluble derivatives have, therefore, been prepared. In this research, chitosan‐vitamin C complexes (CSVC) were synthesized and characterized with FTIR, DSC, and 1H‐NMR. The solubility of CSVC in distilled water was greatly improved. The •O2‐ scavenging activity of CSVC was compared with CS and vitamin C (VC) by measuring the auto‐oxidation rate of pyrogallic acid. Results showed that the scavenging activity on •O2− by CSVC was stronger than that by CS. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Highly stable hexamethylolmelamine microcapsules containing n‐octadecane prepared by in situ encapsulation
Authors: Palanikkumaran M. , Gupta Kishor K. , Agrawal Ashwini K. , Jassal Manjeet
Published: July 2009

A systematic study has been carried out to investigate the effect of formaldehyde‐to‐melamine molar ratio varying from 2.5 to 8, core‐to‐wall ratio from 1 to 4 and curing conditions used during the encapsulation process on the properties of microcapsules that contain n‐octadecane as the core material and melamine‐formaldehyde as the wall material. The microcapsules so obtained were characterized for their core content, encapsulation efficiency, thermal, and solvent stabilities. Using the modified encapsulation process with a formaldehyde‐ to‐melamine ratio of 8 and core‐to‐wall ratio of 2, microcapsules with a high core content of (70%) and a heat storage capacity of >160 J/g could be obtained. The capsules were found to be stable upto a temperature of 100°C and also stable to cyclohexane wash. A thermoregulated fabric was also prepared by coating the capsules on a cellulose‐polyester fabric to give a heat storage capacity of >100 J/g. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Mechanical and dielectric breakdown properties of PBT/TPE, PBT/PBT/PET, and PBT/antioxidant blends
Authors: Shin Hyeyoung , Park Eun‐Soo
Published: July 2009

To improve the thermal aging flexibility of poly(butylene terephthalate) (PBT), PBT was melt‐blended with three type thermoplastic elastomer [poly ether‐ester type (TPE1), polyester‐ester type (TPE2), and poly(buthylene 2,6‐naphthalate)/poly(tetramethylene glycol) block copolymer type (TPE3)], PBT/poly(ethylene terephthalate), (PET) alloy (Alloy), and phosphate type antioxidant (T1). The content of the three type TPEs and Alloy was fixed at 20 parts per 100 g of PBT. The morphology and thermal behavior of these blends have been investigated with scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetry (TG). In the case of PBT/Alloy‐20 and PBT/TPE3–20 blends show clean fractured surface, whereas for PBT/TPE1–20 and PBT/TPE2–20 blends, the elongated pieces or fiber can be seen abundantly which indicates a good compatibility. TG traces show a significant shift of the weight loss toward higher temperature for PBT/Alloy‐20, whereas PBT/TPE1–20, PBT/TPE2–20 and PBT/TPE3–20 blend decrease in thermal stability than PBT. To investigate the applicability for insulation material, the prepared blend samples were extruded an electric wire and flexibility and electric breakdown voltage (BDV) of wire after thermal aging were studied. For PBT/TPE1–20 and PBT/TPE2–20 blends did not show any cracks after flexibility test at 130°C for 6 h and 225°C for 30 min. In contrast PBT, PBT/Alloy‐20, PBT/TPE3–20, and PBT/T1–1 showed a partial crack in the insulation after flexibility test at 130°C for 6 h although its good flexibility at 225°C for 30 min. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and Characterization of Alkynyl Complexes of Groups 1 and 2
Authors: Stasch Andreas , Sarish Sankaranarayana Pillai , Roesky Herbert W. , Meindl Kathrin , Dall'Antonia Fabio , Schulz Thomas , Stalke Dietmar
Published: July 2009

The synthesis of N‐heterocyclic carbene adducts of alkynyl lithium and magnesium is achieved, and different degrees of association are observed. Reaction of strontium amide nacnacSrN(SiMe3)2(thf) (nacnac=CH(CMe2,6‐iPr2C6H3N)2) with PhC≡CH in THF yields the dimeric alkynyl complex [nacnacSr(thf)(μ‐C≡CPh)]2 which shows an interesting coordination geometry around the metal center. The compound retains the THF molecules, unlike its lighter congener, even in hydrocarbon solvents.
Hamiltonian particle‐mesh simulations for a non‐hydrostatic vertical slice model
Authors: Shin Seoleun , Reich Sebastian
Published: July 2009

A Lagrangian particle method is developed for the simulation of atmospheric flows in a non‐hydrostatic vertical slice model. The proposed particle method is an extension of the Hamiltonian particle mesh (HPM) [Frank J, Gottwald G, Reich S. 2002. The Hamiltonian particle‐mesh method. In Meshfree Methods for Partial Differential Equations, Lecture Notes in Computational Science and Engineering, Vol. 26, Griebel M, Schweitzer M (eds). Springer‐Verlag: Berlin Heidelberg; 131–142] and provides preservation of mass, momentum, and energy. We tested the method for the gravity wave test in Skamarock W, Klemp J. 1994. Efficiency and accuracy of the Klemp‐Wilhelmson time‐splitting technique. Monthly Weather Review 122: 2623–2630 and the bubble experiments in Robert A. 1993. Bubble convection experiments with a semi‐implicit formulation of the Euler equations. Journal of the Atmospheric Sciences 50: 1865–1873. The accuracy of the solutions from the HPM simulation is comparable to those reported in these references. A particularly appealing aspect of the method is in its non‐diffusive transport of potential temperature. The solutions are maintained smooth largely due to a ‘regularization’ of pressure, which is controlled carefully to preserve the total energy and the time‐reversibility of the model. In case of the bubble experiments, one also needs to regularize the buoyancy contributions. The simulations demonstrate that particle methods are potentially applicable to non‐hydrostatic atmospheric flow regimes and that they lead to a highly accurate transport of materially conserved quantities such as potential temperature under adiabatic flow regimes. Copyright © 2009 Royal Meteorological Society
Variability in human embryonic development and its implications for the susceptibility to environmental teratogenesis
Authors: Shiota Kohei
Published: July 2009

Considerable variability is observed in the size and developmental stage among human embryos at a given gestational age, suggesting that prenatal development does not proceed at the same speed in every embryo. Such variability in embryonic development seems to occur in many (probably all) animal species, and is probably a normal “biologic” phenomenon to some extent. In the case of humans, some other factors (e.g., maternal memory bias, difficulty in assessing the timing of ovulation and fertilization) make it more difficult to assess the developmental stage of embryos in utero. Such facts related to human embryonic development should be taken into account when the teratogenic risk of a human embryo is considered. Birth Defects Research (Part A), 2009. © 2009 Wiley‐Liss, Inc.
Efficient synthesis of a long carbohydrate chain alkyl glycoside catalyzed by cyclodextrin glycosyltransferase (CGTase)
Authors: Svensson David , Ulvenlund Stefan , Adlercreutz Patrick
Published: July 2009

Alkyl glycosides with long carbohydrate groups are surfactants with attractive properties but they are very difficult to synthesize. Here, a method for extension of the carbohydrate group of commercially available dodecyl‐β‐d‐maltoside (DDM) is presented. DDM was converted to dodecyl‐β‐d‐maltooctaoside (DDMO) in a single step by using a CGTase as catalyst and α‐cyclodextrin (α‐CD) as glycosyl donor. The coupling reaction is under kinetic control and the maximum yield depends on the selectivity of the enzyme. The Bacillus macerans CGTase favored the coupling reaction while the Thermoanaerobacter enzyme also catalyzed disproportionation reactions leading to a broader product range. A high ratio α‐CD/DDM favored a high yield of DDMO and yields up to 80% were obtained using the B. macerans enzyme as catalyst. Biotechnol. Bioeng. 2009; 104: 854–861. © 2009 Wiley Periodicals, Inc.
A liquid chromatography/tandem mass spectrometry method for determination of aristolochic acid‐I in rat plasma
Authors: Liu Yiming , Lin Aihua , Wu Zhifeng , Ou Runmei , Huang Haiding
Published: July 2009

A sensitive, rapid and specific liquid chromatography–electrospray ionization–tandem mass spectrometry method was developed
and validated for the determination of aristolochic acid‐I (AA‐I) in rat plasma. Finasteride was used as the internal standard (IS). The analyte was separated on a Zorbax Eclipse XDB‐C18 column by isocratic elution with methanol‐10 mM ammonium acetate (75:25, v/v, pH = 7.3) at a flow rate of 0.25 mL/min, and analyzed by mass spectrometry in positive multiple reaction monitoring mode. The precursor‐to‐product ion transitions of m/z 359.0 → 298.2 and m/z 373.1 → 305.2 were used to detect AA‐I and IS, respectively. Good linearity was achieved over a range of 0.4–600 ng/mL. Intra‐ and inter‐day precisions measured as relative standard deviation were less than 13.5%, and accuracy ranged from 94.2 to 97.5%. The developed method was successfully applied in the pharmacokinetic study of AA‐I in rats. Copyright © 2009 John Wiley & Sons, Ltd.
Simultaneous assay of sildenafil and desmethylsildenafil in neonatal plasma by ultra‐performance liquid chromatography–tandem mass spectrometry
Authors: Witjes Bregje C. , Ahsman Maurice J. , van der Nagel Bart C. , Tibboel Dick , Mathot Ron A.
Published: July 2009

Sildenafil is used to treat pulmonary hypertension in neonatal and pediatric patients. Pharmacokinetic studies in these patients are complicated by the limited sample volume. We present the validation results of an assay method to quantitate sildenafil and desmethylsildenafil simultaneously in 50 µL of plasma. Deuterated sildenafil was used as an internal standard. After liquid–liquid extraction, analytes were separated on an ultra‐performance liquid chromatography (UPLC)‐column and quantified via tandem mass spectrometry. The calibration range was linear, with acceptable accuracy and a precision of <15% for both compounds. The lower limits of quantification were 1 ng/mL. Matrix effects were present, but inter‐plasma batch variability was under 12%. The method was successfully applied to samples from a pharmacokinetic study into sildenafil pharmacokinetics in neonates, making maximum use of the limited number and amount of plasma samples available. Copyright © 2009 John Wiley & Sons, Ltd.
Rapid and sensitive determination of strychnine and brucine in human urine by capillary electrophoresis with field‐amplified sample stacking
Authors: Li Junmei , Jiang Ye
Published: July 2009

A simple, rapid, sensitive and low‐cost method using capillary electrophoresis (CE) coupled with field‐amplified sample stacking (FASS) has been developed and validated for the simultaneous determination of strychnine and brucine residues in human urine. Before sample loading, a water plug (3.5 kPa, 3 s) was injected to contain sample cations and to permit FASS. Electrokinetic injection at a voltage (20 kV, 25 s) was then used to introduce cations. Separation was performed using 20 mMacetate buffer (pH 3.8) with an applied voltage of 20 kV. The calibration curves were linear over a range of 8.00–2.56 ∞ 102 ng/mL (r= 0.9995) for strychnine and 10.0–3.20 × 102 ng/mL (r= 0.9999) for brucine. Extraction recoveries in urine were greater than 79.6 and 82.8% for strychnine and brucine, respectively, with an RSD of less than 4.9%. The detection limits (signal‐to‐noise ratio 3) for strychnine and brucine were 2.00 and 2.50 ng/mL, respectively. A urine sample from one healthy female volunteer (26 years old, 50 kg) was pretreated and analyzed. Strychnine and brucine levels in urine could be detected 24 h after administration. On these grounds, this method was feasible for application to preliminary screening of trace levels of abused drugs for both doping control and forensic analysis. Copyright © 2009 John Wiley & Sons, Ltd.
Liquid chromatography–mass spectrometry for analysis of a novel β2‐adrenoceptor agonist trantinterol and its metabolites in beagle dog urine
Authors: Wang Yanjuan , Lu Xiumei , Jiang Kun , Xiong Zhili , Cheng Maosheng , Li Famei
Published: July 2009

A liquid chromatography–tandem mass spectrometry method was developed for the identification of metabolites of trantinterol, a novel β2‐adrenoceptor agonist, in beagle dog urine. The separation of metabolites was performed on a reversed‐phase C8 column using 0.1% formic acid in water and methanol (70 : 30, v/v) as the mobile phase. The structural information and elemental information of metabolites were acquired by an electrospray ionization tandem mass spectrometer and a quadrupole time‐of‐flight mass spectrometer, respectively. A total of 13 metabolites were detected and characterized on the basis of their tandem MS/MS fragmentation patterns. The accurate masses of nine metabolites were determined and two metabolites were further confirmed by comparing with reference standards. The metabolic pathways of trantinterol in beagle dog are proposed. Copyright © 2009 John Wiley & Sons, Ltd.
A wheat embryo cell‐free protein synthesis system not requiring an exogenous supply of GTP
Authors: Koga Hirohisa , Misawa Satoru , Shibui Tatsuro
Published: July 2009

Most in vitro protein synthesis systems require a supply of GTP for the formation of translation initiation complexes, with two GTP molecules per amino acid needed as an energy source for a peptide elongation reaction. In order to optimize protein synthesis reactions in a continuous‐flow wheat embryo cell‐free system, we have examined the influence of adding GTP and found that the system does not require any supply of GTP. We report here the preparation of a wheat embryo extract from which endogenous GTP was removed by gel filtration, and the influence of adding GTP to the system on protein synthesis reactions. Using Green Fluorescent Protein (GFP) as a reporter, higher levels of production were observed at lower concentrations of GTP, with the optimal level of production obtained with no supply of GTP. A HPLC‐based analysis of the extract and the translation mixture containing only ATP as an energy source revealed that GTP was not detectable in the extract, however, 35 μM of GTP was found in the translation mixture. This result suggests that GTP could be generated from other compounds, such as GDP and GMP, using ATP. A similar experiment with a C‐terminally truncated form of human protein tyrosine phosphatase 1B (hPTP1B1‐320) gave almost the same result. The wheat embryo cell‐free translation system worked most efficiently without exogenous GTP, producing 3.5 mg/mL of translation mixture over a 48‐h period at 26°C. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
HERC1 polymorphisms: population‐specific variations in haplotype composition
Authors: Yuasa Isao , Umetsu Kazuo , Nishimukai Hiroaki , Fukumori Yasuo , Harihara Shinji , Saitou Naruya , Jin Feng , Chattopadhyay Prasanta K. , Henke Lotte , Henke Jürgen
Published: July 2009

Human HERC1 is one of six HERC proteins and may play an important role in intracellular membrane trafficking. The human HERC1 gene is suggested to have been affected by local positive selection. To assess the global frequency distributions of coding and non‐coding single nucleotide polymorphisms (SNPs) in the HERC1 gene, we developed a new simultaneous genotyping method for four SNPs, and applied this method to investigate 1213 individuals from 12 global populations. The results confirmed remarked differences in the allele and haplotype frequencies between East Asian and non‐East Asian populations. One of the three common haplotypes observed was found to be characteristic of East Asians, who showed a relatively uniform distribution of haplotypes. Information on haplotypes would be useful for testing the function of polymorphisms in the HERC1 gene. This is the first study to investigate the distribution of HERC1 polymorphisms in various populations. Copyright © 2009 John Wiley & Sons, Ltd.
Development of Selective Bisubstrate‐Based Inhibitors Against Protein Kinase C (PKC) Isozymes By Using Dynamic Peptide Microarrays
Authors: Poot Alex J. , van Ameijde Jeroen , Slijper Monique , van den Berg Adriënne , Hilhorst Riet , Ruijtenbeek Rob , Rijkers Dirk T. S. , Liskamp Rob M. J.
Published: July 2009

Kinase inhibitors are increasingly important in drug development. Because the majority of current inhibitors target the conserved ATP‐binding site, selectivity might become an important issue. This could be particularly problematic for the potential drug target protein kinase C (PKC), of which twelve isoforms with high homology exist in humans. A strategy to increase selectivity is to prepare bisubstrate‐based inhibitors that target the more selective peptide‐binding site in addition to the ATP‐binding site. In this paper a generally applicable, rapid methodology is presented to discover such bisubstrate‐based leads. Dynamic peptide microarrays were used to find peptide‐binding site inhibitors. These were linked with chemoselective click chemistry to an ATP‐binding site inhibitor, and this led to novel bisubstrate structures. The peptide microarrays were used to evaluate the resulting inhibitors. Thus, novel bisubstrate‐based inhibitors were obtained that were both more potent and selective compared to their constituent parts. The most promising inhibitor has nanomolar affinity and selectivity towards PKCθ amongst three isozymes.
Characterization of the Rv3377c Gene Product, a Type‐B Diterpene Cyclase, from the Mycobacterium tuberculosis H37 Genome
Authors: Nakano Chiaki , Hoshino Tsutomu
Published: July 2009

The Rv3377c gene from the Mycobacterium tuberculosis H37 genome is specifically limited to those Mycobacterium species that cause tuberculosis. We have demonstrated that the gene product of Rv3377c is a diterpene cyclase that catalyzes the formation of tuberculosinol from geranylgeranyl diphosphate (GGPP). However, the characteristics of this enzyme had not previously been studied in detail with homogeneously purified enzyme. The purified enzyme catalyzed the synthesis of tuberculosinyl diphosphate from GGPP, but it did not bring about the synthesis of tuberculosinol. Optimal conditions for the highest activity were found to be as follows: pH 7.5, 30 °C, MgII (0.1 mM), and Triton X‐100 (0.1 %). Under these conditions, the kinetic values of KM and kcat were determined to be 11.7±1.9 μM for GGPP and 12.7±0.7 min−1, respectively, whereas the specific activity was 186 nmol min−1 mg−1. The enzyme activity was inhibited at substrate concentrations higher than 50 μM. The catalytic activity was strongly inhibited by 15‐aza‐dihydrogeranylgeraniol and 5‐isopropyl‐N,N,N,2‐tetramethyl‐4‐(piperidine‐1‐carbonyloxy)benzenaminium chloride (Amo‐1618). The DXDTT293–297 motif, corresponding to the DXDDTA motif conserved among terpene cyclases, was mutated in order to investigate its function. The middle D295 was found to be the most crucial entity for the catalysis. D293 and two threonine residues function synergistically to enhance the acidity of D295, possibly through hydrogen‐bonding networks. The Rv3377c enzyme could also react with (14R/S)‐14,15‐oxidoGGPP to generate 3α‐ and 3β‐hydroxytuberculosinyl diphosphate. Conformational analyses were carried out with deuterium‐labeled GGPP and oxidoGGPP. We found that GGPP and (14R)‐oxidoGGPP adopted a chair/chair conformation, but (14S)‐oxidoGGPP adopted a boat/chair conformation. Interestingly, the conformations of oxidoGGPP for the A‐ring formation are the opposite of those of oxidosqualene when it is used as a substrate by squalene cyclases for the biosynthesis of hopene and tetrahymanol. (3R)‐Oxidosqualene is folded in a boat conformation, whereas (3S)‐2,3‐oxidosqualene folds into a chair conformation, for the formation of the A‐rings of the hopene and tetrahymanol skeletons, respectively.
Clinical safety and efficacy of a novel thin‐strut cobalt–chromium coronary stent system: Results of the real world Coroflex Blue Registry
Authors: Bocksch Wolfgang , Pomar Francisco , Dziarmaga Mieczyslaw , Tresukosol Damras , Ismail Omar , Janek Bronislav , Carlsson Joerg , Simon Jean‐Philippe
Published: July 2009

Objectives: The aim of this registry was to evaluate the clinical efficacy and safety of the Coroflex Blue cobalt–chromium stent in real‐world practice. Background: The development of cobalt–chromium bare‐metal stents (BMS) with thinner struts has lead to better deliverability and lower target‐lesion revascularization rates compared with stainless steel BMS. Methods: The Coroflex Blue Registry was an international, prospective, multicenter registry enrolling patients with symptomatic ischemic heart disease attributable to single de novo or restenotic nonstented lesions of a single vessel amenable for percutaneous stenting. The primary end point was clinically driven target‐lesion revascularisation (TLR) 6 months after enrolment, secondary endpoints were technical/procedural success, in‐hospital outcome, definite stent thrombosis and major adverse cardiac events (death, myocardial infarction, or TLR) after 6 months. Results: The registry included 2,315 patients (mean age 64.3 ± 11.1 years, 19.8% diabetes, 37.3% acute myocardial infarction). Although a complex lesion cohort with 60.3% Typ B2/C‐lesions, the technical success rate was 99.1% and the procedural success rate 98.5%. The incidence of TLR after 6 months was 5.5% and the cumulative 6‐month acute/subacute stent thrombosis rate was 1.6%. After 6 months cumulative event‐free survival was 90.8% in all patients and 87% in patients with acute PCI for acute myocardial infarction. Conclusions: This registry demonstrates the safety and efficacy of the Coroflex Blue cobalt–chromium stent platform in real‐world practice. In the era of drug‐eluting stents (DES), these results raise the serious question if the use of DES for primary prevention of restenosis and TLR is really justified.
Real case virtual reality training prior to carotid artery stenting
Authors: Roguin Ariel , Beyar Rafael
Published: July 2009

Background: The majority of procedural training especially in interventional cardiology, still occurs on patients with direct mentoring by experienced physicians during an actual clinical procedure. In recent years there is an increase use of simulators especially for carotid artery stenting. However, most simulators use “generic” predefined cases. Methods and Result: We report here a simulation done on data of a real patient prior to intervention. The patient's specific carotid anatomy was modeled using CTA on an endovascular simulator. Pre‐procedure patient‐specific case rehearsal accurately predicted procedure experience. Conclusions: A case rehearsal prior to an intervention may be useful in the planning and execution of carotid artery stenting. The use of patient specific simulation helps with planning of procedure and device selection, and may lead to use of less contrast and radiation, and shorter procedure duration. These may benefit the patient with increased success and lower complication rates. © 2009 Wiley‐Liss, Inc.
Drug‐eluting stent fracture: Incidence, contributing factors, and clinical implications
Authors: Canan Timothy , Lee Michael S.
Published: July 2009

Stent fracture has been observed in noncoronary vessels, especially in the superficial femoral and popliteal arteries and with bare metal stents in saphenous vein grafts of coronary arteries. Since the introduction of drug‐eluting stents, stent fractures have also been reported in small studies and case reports. We reviewed these publications to assess what is known regarding the incidence, contributing factors, and clinical implications of drug‐eluting stent fracture in coronary arteries. The reported rate of drug‐eluting stent fracture in coronary arteries ranges from 1 to 8%, although much of the available literature is derived from single‐center studies that are heterogeneous in their study methods. A higher risk of stent fracture may be associated with the right coronary artery location, excessive tortuosity or angulation of the vessel, overlapping stents, and longer stents. The closed‐cell design of the Cypher stent has been associated with increased rigidity that may increase the risk of stent fracture, although these studies did not assess the overall outcomes between the Cypher and Taxus stents in a head‐to‐head comparison. Stent fracture has been shown by most studies to be associated with a statistically increased incidence of focal in‐stent restenosis, and some have shown an increased risk of target lesion revascularization. Other complications observed with stent fracture include stent thrombosis, coronary aneurysms, myocardial infarction, and sudden death. © 2009 Wiley‐Liss, Inc.
X‐Ray Photoelectron Spectroscopy and Reactivity Studies of a Series of Ruthenium Catalysts
Authors: Jarzembska Katarzyna , Seal Sudipta , Woźniak Krzysztof , Szadkowska Anna , Bieniek Michał , Grela Karol
Published: July 2009

X‐Ray photoelectron spectroscopy (XPS) was applied to six selected ruthenium precatalysts. The XPS data obtained were compared against reactivity and structural results. The XPS data confirmed some dependencies such as the electron‐donor properties of the substituents at the ruthenium center. Additionally, the data combined with structural and reactivity results explain the differences between the character of Grubbs and Hoveyda catalysts. It was found that changing the PCy3 ligand to OiPr (PCy3=tricyclohexylphosphane, OiPr=isopropoxy) has a major influence on relative electron‐donating properties of the N‐heterocyclic carbene ligand (NHC) and PCy3 groups, which was supported by the relative charges on the Ru center for the examined compounds. Moreover, the turnover frequency (TOF) of a selected example reaction decreased when introducing a NHC group in the case of Grubbs catalysts, but increased in the case of Hoveyda‐type catalysts. The XPS data also explained the relative activity values of some catalysts (higher reactivity of nitro‐Hoveyda than Hoveyda second‐generation catalysts). However, the binding energies do not predict TOFs. Sole examination of the XPS data does not provide a base for reaching unambiguous and binding conclusions as to the relative reactivity of all the investigated systems.
Alkene Polymerization Catalysts Bearing Tridentate Phenoxyamine Ligands with sp3 C Donors
Authors: Edson Joseph B. , Keresztes Ivan , Lobkovsky Emil B. , Coates Geoffrey W.
Published: July 2009

The reaction of vinyl‐appended phenoxyamine 2 with tetrabenzyltitanium provided the phenoxyaminetitanium(II) alkene complex [rac‐Lig2TiBn], arising from intramolecular vinyl‐group insertion followed by toluene elimination. Whereas [rac‐Lig2TiBn] was inactive for olefin polymerization upon benzyl abstraction, treatment with ethylene led to the formation of stable titanacyclopentane complex [rac‐Lig2(CH2)2TiBn]. Alternatively, six‐membered metallacyclic complexes [rac‐Lig1ZrBn2‐a/b] and [rac‐Lig1HfBn2‐a/b] were obtained from reaction of vinyl‐appended phenoxyamine 1 with tetrabenzylzirconium or tetrabenzylhafnium in a further rare example of intramolecular vinyl‐group insertion into neutral tribenzyl group IV precursors. Living and isoselective polymerization of 1‐hexene was promoted by [rac‐Lig1HfBn2‐a/b]/B(C6F5)3 at 0 °C, whereas [rac‐Lig1ZrBn2‐a/b]/B(C6F5)3 catalyzed the living and isoselective polymerization of propylene ([m4]=0.76) at 0 °C. This catalyst system was employed for the synthesis of a diblock copolymer featuring an isotactic polypropylene semicrystalline block and poly(ethylene‐co‐propylene) amorphous block.
A nonlinear partial least squares algorithm using quadratic fuzzy inference system
Authors: Abdel‐Rahman Araby I. , Lim Gino J.
Published: July 2009

We introduce a new nonlinear partial least squares algorithm ‘Quadratic Fuzzy PLS (QFPLS)’ that combines the outer linear Partial Least Squares (PLS) framework and the Takagi–Sugeno–Kang (TSK) fuzzy inference system. The inner relation between the input and the output PLS score vectors is modeled by a quadratic TSK fuzzy inference system. The performance of the proposed QFPLS method is tested and compared against four other well‐known partial least squares methods (Linear PLS (LPLS), Quadratic PLS (QPLS), Linear Fuzzy PLS (LFPLS), and Neural Network PLS (NNPLS)) on various different types of randomly generated test data. QFPLS outperformed competitors based on two comparison measures: the output variables cumulative per cent variance captured by the PLS latent variables and the root mean‐square error of prediction (RMSEP). Copyright © 2009 John Wiley & Sons, Ltd.
Ligand Recognition Processes in the Formation of Homochiral C3‐Symmetric LnL3 Complexes of a Chiral Alkoxide
Authors: Arnold Polly L. , Buffet Jean‐Charles , Blaudeck Robert , Sujecki Slawomir , Wilson Claire
Published: July 2009

The reaction of a chiral racemic bidentate ligand HL1 (tBu2P(O)CH2CH(tBu)OH) with mid to late trivalent lanthanide cations affords predominantly homochiral lanthanide complexes (RRR)‐[Ln(L1)3] and (SSS)‐[Ln(L1)3]. A series of reactions are reported that demonstrate that the syntheses are under thermodynamic control, and driven by a ligand ‘self‐recognition’ process, in which the large asymmetric bidentate L1 ligands pack most favourably in a C3 geometry around the lanthanide cation. The synthesis of bis(L1) adducts [Ln(L1)2X] (X=N(SiMe3)2, OC6H3tBu‐2,6) is also reported. Analysis of the diastereomer mixtures shows that homochiral (L1)2 complexes are favoured but to a lesser extent. The complexes Ln(L1)3 and [Ln(L1)2(OC6H3tBu‐2,6)] have been studied as initiators for the polymerization of ε‐caprolactone and its copolymer with lactide, glycolide and its copolymer with lactide, and ε‐caprolactam.
The Formation of Large‐Area Conducting Graphene‐Like Platelets
Authors: Salvio Riccardo , Krabbenborg Sven , Naber Wouter J. M. , Velders Aldrik H. , Reinhoudt David N. , van der Wiel Wilfred G.
Published: July 2009

The treatment of a suspension of graphite oxide (GO) with sodium azide leads to a material that, after reduction, features amino groups at the top and bottom of the sheets. These groups react through microcontact printing with an isothiocyanate monolayer on a silicon oxide substrate to form covalent bonds that strongly attach to the particles on the surface. With ultrasonication it is possible to obtain exfoliation of the sheets that are not covalently bound to the surface leaving single‐layer platelets attached to the substrate. The azido derivative can be also used to functionalize the graphene oxide with long alkylic chains through a click chemistry approach. This functionalization results in the exfoliation of this material in dimethylformamide. The novel materials were fully characterized by different techniques including IR spectroscopy, thermogravimetric analysis (TGA), scanning and transmission electron microscopy (SEM and TEM), X‐Ray photoelectron spectroscopy (XPS), and solid state NMR spectroscopy. The material with amino groups, after the reduction step, is conductive with a resistivity only approximately seven times larger than that of unprocessed graphite. This implies that after reduction of the GO, the conjugated sp2 network is largely restored. We consider this to be an important step towards a chemical approach for forming conducting large‐area platelet films of single‐layer graphene.
Seeking the Chemical Roots of Darwinism: Bridging between Chemistry and Biology
Authors: Pross Addy
Published: July 2009

Chemistry and biology are intimately connected sciences yet the chemistry–biology interface remains problematic and central issues regarding the very essence of living systems remain unresolved. In this essay we build on a kinetic theory of replicating systems that encompasses the idea that there are two distinct kinds of stability in nature—thermodynamic stability, associated with “regular” chemical systems, and dynamic kinetic stability, associated with replicating systems. That fundamental distinction is utilized to bridge between chemistry and biology by demonstrating that within the parallel world of replicating systems there is a second law analogue to the second law of thermodynamics, and that Darwinian theory may, through scientific reductionism, be related to that second law analogue. Possible implications of these ideas to the origin of life problem and the relationship between chemical emergence and biological evolution are discussed.
Regio‐ and Stereoselectivity in the Decatungstate Photocatalyzed Alkylation of Alkenes by Alkylcyclohexanes
Authors: Dondi Daniele , Ravelli Davide , Fagnoni Maurizio , Mella Mariella , Molinari Alessandra , Maldotti Andrea , Albini Angelo
Published: July 2009

Tetrabutylammonium decatungstate (WO) photocatalyzes radical alkylation reactions starting directly from alkanes. When using tert‐butylcyclohexane and methylcyclohexane as the radical precursors, the addition to electrophilic alkenes (β,β‐dialkylmethylenemalononitriles, acrylonitrile, methyl acrylate, methyl vinyl ketone) is regioselective and exclusively gives 3‐ and 4‐substituted cyclohexyl adducts, with no significant functionalization of the other positions. Furthermore, when a β,β‐disubstituted alkene is used, the reaction is stereoselective (cis stereochemistry for the 1,3‐cyclohexane derivatives and trans for the 1,4 isomers). Some of the reactions have also been carried out by using benzophenone as the photocatalyst, giving the same product distribution. However, the decatungstate anion is a superior catalyst from a preparative point of view, because it is efficient at low concentrations (0.002 m, 2 mol %) and allows for a simple work up. From a mechanistic point of view, the role of both the alkyl radicals and the radical adducts has been assessed by trapping experiments in the presence of suitable additives (α‐phenyl‐N‐tert‐butylnitrone, PBN, and 2‐methyl‐2‐nitrosopropane, MNP) and by EPR spectroscopic detection of the resulting nitroxides in solution. Furthermore, trapping by the nitroxide TEMPO (TEMPO=2,2,6,6‐tetramethylpiperidine N‐oxide) gives O‐(tert‐butylcyclohexyl)hydroxylamines, again as only the 3‐ and the 4‐substituted isomers. We conclude that the observed regioselective activation originates from the initial hydrogen abstraction step (the statistically corrected ratio for positions 3 and 4 ranges from 1.1 to 1.35 for all of the trapping products). The selectivity is mainly due to steric hinderence.
Electrochemical Properties and Computations of Stable Radicals of the Heavy Group 14 Elements (Si, Ge, and Sn)
Authors: Becker James Y. , Lee Vladimir Ya. , Nakamoto Masaaki , Sekiguchi Akira , Chrostowska Anna , Dargelos Alain
Published: July 2009

A series of stable radicals centered on persilyl‐substituted heavy Group 14 elements, (tBu2MeSi)3E. (E=Si, Ge, Sn), was studied by cyclic voltammetry in different solvents to determine their first oxidation and reduction potentials and to compare their ease of oxidation and reduction with known experimental and computed ionization energies (Ei) and electron affinities (Eea), respectively. It has been observed that all of the first oxidation and reduction potentials for the three radicals studied are irreversible in o‐dichlorobenzene (o‐DCB), whereas the reduction waves are quasi‐reversible in THF. A good correlation has been found between measured oxidation potentials and ionization energy values, but no correlation between reduction potentials and electron affinity values was found, probably due to kinetic and surface effects.
ChemInform Abstract: Incompressibility and Hardness of Solid Solution Transition Metal Diborides: Os1‐xRuxB2.
Authors: Weinberger Michelle B. , Levine Jonathan B. , Chung Hsiu‐Ying , Cumberland Robert W. , Rasool Haider I. , Yang Jenn‐Ming , Kaner Richard B. , Tolbert Sarah H.
Published: July 2009

ChemInform 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: Theoretical Investigation of the Electronic and Optical Properties of Zn2OX (X: S, Se, Te) in Chalcopyrite Phase by Full Potential Methods
Authors: Ramasubramanian S. , Thangavel R. , Rajagopalan M. , Kumar J.
Published: July 2009

ChemInform 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: Three Redox States of Nitrosyl: NO+, NO·, and NO‐/HNO Interconvert Reversibly on the Same Pentacyanoferrate(II) Platform.
Authors: Montenegro Andrea C. , Amorebieta Valentin T. , Slep Leonardo D. , Martin Diego F. , Roncaroli Federico , Murgida Daniel H. , Bari Sara E. , Olabe Jose A.
Published: July 2009

ChemInform 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: The First Structure with Isolated Carbon‐Centered Tetrahedra of Rare‐Earth Metals — The New Compound Ce4CCl8.
Authors: Schaloske Manuel C. , Kienle Lorenz , Hoch Constantin , Mattausch Hansjuergen , Kremer Reinhard K. , Simon Arndt
Published: July 2009

ChemInform 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: High‐Pressure — High‐Temperature Synthesis of Na6MnO4.
Authors: Pfeiffer Steffen , Jansen Martin
Published: July 2009

ChemInform 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: New Types of o‐Carborane‐Based Chiral Phosphinooxazoline (Cab‐PHOX) Ligand Systems: Synthesis and Characterization of Chiral Cab‐PHOX Ligands and Their Application to Asymmetric Hydrogenation.
Authors: Lee Jong‐Dae , Co Thanh Thien , Kim Tae‐Jeong , Kang Sang Ook
Published: July 2009

ChemInform 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: Palladium‐Catalyzed Heck and Suzuki Coupling in Glycerol.
Authors: Wolfson A. , Dlugy C.
Published: July 2009

ChemInform 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: Nickel‐Catalyzed Cross‐Coupling of Nonactivated and Functionalized Alkyl Halides with Alkyl Grignard Reagents.
Authors: Vechorkin Oleg , Hu Xile
Published: July 2009

ChemInform 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: A Broadly Applicable Mild Method for the Synthesis of gem‐Diperoxides from Corresponding Ketones or 1,3‐Dioxolanes.
Authors: Li Yun , Hao Hong‐Dong , Zhang Qi , Wu Yikang
Published: July 2009

ChemInform 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: Rhodium(I)‐Catalyzed Reductive Cyclocarbonylation of Internal Alkynes: Atom‐Economic Process for Synthesis of 2‐Cyclopenten‐1‐ones, 5‐Alkylidenefuran‐2(5H)‐ones and Indan‐1‐ones.
Authors: Huang Qiufeng , Hua Ruimao
Published: July 2009

ChemInform 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: Push—Pull Alkenes by Reacting N,N′‐Dimethyl Cyclic Ketene N,N′‐Acetals with Isocyanates: Synthesis, Structures, and Reactivities.
Authors: Ye Guozhong , Henry William P. , Chen Chunlong , Zhou Aihua , Pittman Charles U. Jr.
Published: July 2009

ChemInform 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: One‐Pot Synthesis of Phenacyl Esters from Acetophenone, [Bmim]Br3, and Potassium Salts of Carboxylic Acids under Solvent‐Free Conditions.
Authors: Le Zhang‐Gao , Xie Zong‐Bo , Xu Jian‐Ping
Published: July 2009

ChemInform 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: Organocatalytic Asymmetric Sulfa‐Michael Additions to α,β‐Unsaturated Sulfonates.
Authors: Enders Dieter , Hoffman Krzysztof
Published: July 2009

ChemInform 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: p‐Phenylene Sulfide Oligomers and Their Properties. Ar—S Couplings Mediated by Copper or by Fluorine Substitutions.
Authors: Goyot Olivier , Gingras Marc
Published: July 2009

ChemInform 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: meta‐ and para‐Difunctionalization of Arenes via an ortho‐Magnesiation and a Subsequent Sulfoxide—Magnesium Exchange.
Authors: Melzig Laurin , Rauhut Christian B. , Knochel Paul
Published: July 2009

ChemInform 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: Microwave‐Assisted Mannich Reaction of 2‐Hydroxy‐chalcones.
Authors: Dong Xiaowu , Liu Tao , Chen Jing , Ying Huazhou , Hu Yongzhou
Published: July 2009

ChemInform 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: Triflic Acid Promoted Synthesis of Polycyclic Aromatic Compounds.
Authors: Li Ang , DeSchepper Daniel J. , Klumpp Douglas A.
Published: July 2009

ChemInform 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: Efficient Chirality Switching in the Asymmetric Addition of Indole to N‐Tosylarylimines in the Presence of Axially Chiral Cyclometalated Bidentate N‐Heterocyclic Carbene Palladium(II) Complexes.
Authors: Liu Zhen , Shi Min
Published: July 2009

ChemInform 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: A Practical, Clean and Green Synthesis of Vibrindole and Bis(indolyl)methanes Catalyzed by Alum [KAl(SO4)2·12H2O] in Water.
Authors: Kumar Sanjay , Grover Inderpreet S. , Sandhu Jagir S.
Published: July 2009

ChemInform 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: Copper‐Catalyzed Selective S‐Arylation of 1,2‐Bis(o‐Amino‐1H‐pyrazolyl) Disulfides with Arylboronic Acids.
Authors: Luo Pei‐Song , Wang Feng , Li Jin‐Heng , Tang Ri‐Yuan , Zhong Ping
Published: July 2009

ChemInform 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: Derivatives of α,β‐Dehydroamino Acids. Part 5. Intramolecular Cyclization of 2‐{2‐[(Z)‐1‐Benzamido‐2‐phenylvinyl]acetamidomethyl}benzimidazole.
Authors: Topuzyan V. O. , Kazandzhyan M. M. , Tamazyan R. A. , Aivazyan A. G.
Published: July 2009

ChemInform 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: Conjugate Addition of Sodium Methanesulfinate to Vinyl Pyridines and Diazines for the Synthesis of Aliphatic Sulfones.
Authors: Schaaf Gregory M. , Mukherjee Sabuj , Waterson Alex G.
Published: July 2009

ChemInform 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: Efficient Synthesis of 1,2,4‐Triazolo[4,3‐a][1,8]naphthyridines under Microwave Irradiation.
Authors: Mogilaiah K. , Swamy T. Kumara , Kumar K. Shiva
Published: July 2009

ChemInform 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.