bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation, characterization, and protein loading properties of N‐acyl chitosan nanoparticles
Authors: Cho Youngjin , Kim Jun Tae , Park Hyun Jin
Published: October 2011

Various N‐acyl chitosans with propionyl‐, hexanoyl‐, nonanoyl‐, lauroyl‐, pentadecanoyl‐, and stearoyl‐groups were synthesized and self‐aggregated N‐acyl chitosan nanoparticles (CSNPs) were prepared by sonication. By the modification with N‐acyl groups, CSNPs increased their hydrophobic character and changed its structural features to be more suitable as a delivery carrier. The mean diameters of bovine serum albumin (BSA)‐loaded N‐acyl CSNPs ranged from 138 to 551 nm. Uniform particle size distribution of BSA‐loaded N‐acyl CSNPs was observed. The protein loading efficiency of N‐acyl CSNPs was about 94–95% with lower BSA concentration (0.1 mg/mL) and not significantly different with acyl chain length. With higher BSA concentration (1.0 mg/mL), however, the highest protein loading efficiency was observed with lauroyl and pentadecanoyl CSNPs. The results suggest that lauroyl and pentadecanoyl CSs are interesting candidates for protein delivery system. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Investigation of solid supported dendrimers for water disinfection
Authors: Gangadharan D. , Dhandhala Nirav , Dixit Dhara , Thakur Rajendra Singh , Popat Kiritkumar Mangaldas , Anand P. S.
Published: October 2011

Polystyrene copolymer beads supported dendrimer was synthesized and investigated for its biological applications. Macroporous cross‐linked polystyrene copolymer beads were synthesized using suspension polymerization. Two successive generations of di(chloroethyl) amine‐type end group functionality was formed on the polystyrene copolymer beads. Elemental analysis, Fourier transform infrared spectra, and solid state13C NMR spectra were employed to characterize the polymer bound dendrimer. The polymer bound dendrimer was tested for antibacterial action against both Gram‐positive and Gram‐negative bacteria. The activity against both types of organism increased with an increase in the nitrogen atoms in the polymer back bone. The dendritic structure containing both amino and di(chloroethyl) groups showed significant reduction in the bacterial count when kept in 20 mL autoclaved water with bacterial cultures having an initial count in the range of 12–83 × 106CFU/mL. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Mechanical properties and morphology of polypropylene‐calcium carbonate nanocomposites prepared by dynamic packing injection molding
Authors: Gao Xueqin , Deng Cong , Ren Chao , Zhang Jie , Li Zhongming , Shen Kaizhi
Published: October 2011

In this article, dynamic packing injection molding (DPIM) technology was used to prepare injection samples of Polypropylene‐Calcium Carbonate (PP/CaCO3) nanocomposites. Through DPIM, the mechanical properties of PP/nano‐CaCO3 samples were improved significantly. Compared with conventional injection molding (CIM), the enhancement of the tensile strength and impact strength of the samples molded by DPIM was 39 and 144%, respectively. In addition, the tensile strength and impact strength of the PP/nano‐CaCO3 composites molded by DPIM increase by 21 and 514%, respectively compared with those of pure PP through CIM. According to the SEM, WAXD, DSC measurement, it could be found that a much better dispersion of nano‐CaCO3 in samples was achieved by DPIM. Moreover, γcrystal is found in the shear layer of the DPIM samples. The crystallinity of PP matrix in DPIM sample increases by 22.76% compared with that of conventional sample. The improvement of mechanical properties of PP/nano‐CaCO3 composites prepared by DPIM attributes to the even distribution of nano‐CaCO3 particles and the morphology change of PP matrix under the influence of dynamic shear stress. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation of PE nanocomposites using pristine nano clay via alkyl ammonium solution injection in a twin‐screw extruder
Authors: Sarikhani K. , Abdollahi S. , Garmabi H.
Published: October 2011

In this study, saline water was used as a preintercalating agent for pristine clay surface to assist clay dispersion in one‐step melt state process. The solution contains dodecyl trimethyl ammonium chloride salt in distilled water and was injected into the twin‐screw extruder using a high pressure dosing pump. To investigate the effect of dissolution of alkyl salt on clay dispersion, two samples with the same compositions were prepared through both salt solution and pure water injection which was compared with organo‐modified prepared sample. The resultant compounds were characterized using x‐ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and dynamic rheological measurements (RMS). Tensile and notched‐Izod impact properties of the samples were measured as well. The XRD results showed no peak for the sample containing 2 wt % pristine clay, prepared via injection of salt solution representing exfoliated microstructure. In addition, TEM images showed proper dispersion and distribution of clay platelets in the matrix. Furthermore, RMS results showed that the slop of the storage modulus has been declined and for the sample using saline, the variation was prominent as a result of network structure formation. Tensile results also showed an increase of tensile modulus in the range of about 22% for the sample containing 2 wt % clay. Izod impact strength in the sample prepared via injection of salt solution showed fracture energy comparable to neat polyethylene. Additionally, the crystallization data in terms of degree of crystallinity, melting, and crystallization temperatures of samples represented no noticeable change compared to neat polyethylene. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Modification of cement with succinic anhydride‐based hyperbranched polyesteramide
Authors: Amin Amal , Darweesh Hassan M. , Ramadan Ahmed M. , Morsi Samir M. M. , Ayoub Magdy M. H.
Published: October 2011

Two hyperbranched polyesteramides (HYP1 and HYP2) were prepared by reacting succinic anhydride (ScAn) with both of diisopropanolamine (DiPA) and diethanolamine, respectively, via one‐pot polycondensation reaction. The prepared polymers were analyzed using gel permeation chromatography, infrared spectra, and 1HNMR. The resulting hydroxyl‐ended resins have been successfully applied as polymeric admixtures in two types of cements such as Ordinary Portland cement and Portland limestone cement. The water of consistency decreased by addition of the hyperbranched polymers in both types of cements. Better hydration was observed by incorporation of small amounts of polymers. The infrared spectra and scanning electron microscopy photos of Ordinary Portland cement and Portland limestone cement pastes premixed with HYP1 and HYP2 showed no effect on the chemical composition of the cement hydrates where only the morphology and the crystallinity of the formed hydrates were changed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
A study on nanofiller effects of serpentine in polypropylene matrix
Authors: Tan Semra , Tinçer Teoman
Published: October 2011

The nanocomposite materials were prepared using serpentine as filler and polypropylene (PP) as the matrix in the presence of maleic anhydride grafted polypropylene (PP‐g‐MA) compatibilizer. The melt intercalation was carried out following serpentine modification with a quaternary salt of cetyl‐trimethyl‐ammonium bromide. The structure of nanocomposites was shown by X‐ray diffraction (XRD) and transmission electron microscopy (TEM) studies. Thermal analysis performed by differential scanning calorimetry (DSC) demonstrated that the nanocomposites have higher percentage crystallinity when compared to neat PP. Dynamic mechanical analysis (DMA) revealed that the storage and loss moduli values of the nanocomposites are better than those of the matrix resin. Tensile properties of nanocomposites are significantly different from PP, e.g., the Young's modulus of the nanocomposite with 2 wt % serpentine and 6 wt % PP‐g‐MA (PP‐2,6Q) was found to be 2065 MPa, i.e., nearly 190.8% increase over the PP matrix. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Comparative Structural Analysis of α‐Glucosidase Inhibitors on Difference Species: A Computational Study
Authors: Narayana Moorthy N. S. Hari , Ramos Maria J. , Fernandes Pedro A.
Published: October 2011

Structural feature analysis of chlorogenic acid derivatives made up of varying lengths of alkyl groups as α‐glucosidases inhibitors were performed by QSAR techniques. The statistically significant models derived from the study were validated by leave one out, Y‐randomization and test set methods. The predictive capacity of the models was assessed by its validation parameters such as crossvalidated correlation coefficients (Q2), predictive residual analysis and other correlation parameters. The results obtained from the study show that the models were constructed with vsurf like properties (vsurf_ID4, vsurf_ID7 and vsurf_CW8), partial charge (Q_VSA_FNEG) and conformation dependent charged (dipoleX) descriptors. The integy moments of hydrophobicity descriptors (ID4 and ID7) are contributed for the inhibitory activity of the α‐glucosidases enzymes of both the species. The vsurf_ID7 descriptor has contributed significantly (negatively) for the inhibitory activity prediction of α‐glucosidases enzymes of S. cerevisiae. The partial negative charge on the surface of the molecules is detrimental for the activity, which reveals that the active site of the enzymes may have negatively charged groups. The pharmacophore analysis results also confirm the presence of hydrophilic properties on the vdW surface of the molecules. These results explain that the active sites of α‐glucosidase enzymes of both the species have the same environment for the interaction. The alkyl side chain on the molecules is important for the pharmacokinetic behavior of the molecules and reduces the interaction energy of the molecules with the water. Hence, these results will be useful for designing novel molecules with multiple activities.
Synthesis and Anticholinesterase Activity and Cytotoxicity of Novel Amide Derivatives
Authors: Altintop Mehlika Dilek , Kaplancikli Zafer Asim , Ozdemir Ahmet , Turan‐Zitouni Gülhan , Temel Halide Edip , Akalın Gülşen
Published: October 2011

In the present study, some amide derivatives were synthesized and their potential anticholinesterase properties were investigated. N‐(Benzothiazol‐2‐yl)‐2‐[(5‐amino/methyl‐1,3,4‐thiadiazol‐2‐yl)thio]acetamide derivatives were obtained by nucleophilic substitution of 2‐chloro‐N‐(benzothiazole‐2‐yl)acetamide derivatives with appropriate 1,3,4‐thiadiazole‐2‐thioles. The chemical structures of the compounds were elucidated by 1H‐NMR, 13C‐NMR and FAB+‐MS spectral data and elemental analyses. Each amide derivative was evaluated for its ability to inhibit AChE and BuChE using a modification of Ellman's spectrophotometric method. The compounds were also investigated for their cytotoxic properties using MTT assay. 2‐(5‐Amino‐1,3,4‐thiadiazol‐2‐yl)thio‐N‐(benzothiazol‐2‐yl)acetamide derivatives have anticholinesterase activity, whereas 2‐(5‐methyl‐1,3,4‐thiadiazol‐2‐yl)thio‐N‐(benzothiazol‐2‐yl)acetamide derivatives have no inhibitory effect on enzyme activity. Among these compounds, it is clear that compound IIh is the most potent derivative.
Solutions of the generalized Sylvester matrix equation and the application in eigenstructure assignment
Authors: Yang Chunlei , Liu Jianzhou , Liu Yu
Published: October 2011

In this paper, a numerical solution to the problem of eigenstructure assignment for descriptor systems is investigated. To this end, we obtain numerical solutions of the generalized Sylvester matrix equation AV + BW = EVF using an iterative method. Based on the presented solution of this equation, an approach using a generalized inverse matrix for eigenstructure assignment in continuous descriptor system via descriptor variable feedback u = Kx is proposed. Finally, some numerical results show the effectiveness of the proposed approach.

Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
A novel in situ probe for oxygen uptake rate measurement in mammalian cell cultures
Authors: Behr Larissa , Joeris Klaus , Burnett Mark , Scheper Thomas
Published: October 2011

The newly developed in situ oxygen uptake rate (in situ OUR) probe presented in this article is based on the in situ microscope technology platform. It is designed to measure the oxygen uptake rate (OUR) of mammalian cells, an important parameter for metabolic flux analysis, inside a reactor (in situ) and in real‐time. The system isolates a known volume of cell culture from the bulk inside the bioreactor, monitors the oxygen consumption over time, and releases the sample again. The sample is mixed during the measurement with a new agitation system to keep the cells in suspension and prevent oxygen concentration gradients. The OUR measurement system also doubles as a standard dissolved oxygen (DO) probe for process monitoring when it is not performing OUR measurements. It can be equipped with two different types of optical sensors (i.e., DO, pH) simultaneously or a conventional polarographic DO‐probe (Clark type). This new probe was successfully tested in baby hamster kidney perfusion cell cultures. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Adenovirus‐mediated expression of hypoxia‐inducible factor 1α double mutant converts neonatal cardiac fibroblasts into (cardio)myocyte phenotype
Authors: Wang Yesong , Sun Aijiao , Xue Jiaojie , Jiang Yi
Published: October 2011

Adenovirus‐mediated expression of hypoxia‐inducible factor 1α double mutant (pAd‐HIF‐1α‐Ala564‐Ala803) can be effectively transfected into bone marrow stem cells (MSCs) in the MSCs and cardiomyocytes co‐culture system at normoxia to regulate the expression of downstream target genes of hypoxia‐inducible factor 1α (HIF‐1α), which in turn can promote MSC differentiation into cardiomyocytes. Fibroblasts share common characteristics with MSCs such as the morphology, phenotype and differentiation potential. Therefore, we further studied whether the pAd‐HIF‐1α‐Ala564‐Ala803 also can convert neonatal rat cardiac fibroblasts (NCFs) into (cardio)myocyte phenotype via regulating the downstream target genes of HIF‐1α at normoxia. The immunostaining analysis showed that NCFs treated with pAd‐HIF‐1α‐Ala564‐Ala803 exhibited higher protein expression levels of smooth muscle α‐actin (SMA, myocyte marker) and cardiac troponin T (cTnT, cardiomyocyte marker), compared with phosphate‐buffered saline and pAd‐LacZ treatments. The reverse transcription‐polymerase chain reaction results showed that NCFs transfected with pAd‐HIF‐1α‐Ala564‐Ala803 augmented messenger RNA (mRNA) expression of transforming growth factor‐β1 (TGF‐β1), Smad4, NKx2.5, GATA4, myocardin, SMA and cTnT. The effects of HIF‐1α‐Ala564‐Ala803 on NCFs were attenuated by pre‐transfection of TGF‐β1 or myocardin small interference RNAs. Adult CFs transfected with pAd‐HIF‐1α‐Ala564‐Ala803 showed a lower protein expression of SMA but not cTnT without any change in the mRNA expression level of NKx2.5, myocardin. Therefore, NCFs but not adult CFs possess a similar differentiation potential to MSCs as evidenced by the fact that pAd‐HIF‐1α‐Ala564‐Ala803 can convert NCFs into (cardio)myocyte phenotype via regulating its downstream target genes. Copyright © 2011 John Wiley & Sons, Ltd.
Multivariate quality control solved by one‐class partial least squares regression: identification of adulterated peanut oils by mid‐infrared spectroscopy
Authors: Xu Lu , Cai Chen‐Bo , Deng De‐Hua
Published: October 2011

The Partial least squares class model (PLSCM) was recently proposed for multivariate quality control based on a partial least squares (PLS) regression procedure. This paper presents a case study of quality control of peanut oils based on mid‐infrared (MIR) spectroscopy and class models, focusing mainly on the following aspects: (i) to explain the meanings of PLSCM components and make comparisons between PLSCM and soft independent modeling of class analogy (SIMCA); (ii) to correct the estimation of the original PLSCM confidence interval by considering a nonzero intercept term for center estimation; (iii) to investigate the potential of MIR spectroscopy combined with class models for identifying peanut oils with low doping concentrations of other edible oils.

It is demonstrated that PLSCM is actually different from the ordinary PLS procedure, but it estimates the class center and class dispersion in the framework of a latent variable projection model. While SIMCA projects the original variables onto a few dimensions explaining most of the data variances, PLSCM components consider simultaneously the explained variances and the compactness of samples belonging to the same class. The analysis results indicate PLSCM is an intuitive and easy‐to‐use tool to tackle one‐class problems and has comparable performance with SIMCA. The advantages of PLSCM might be attributed to the great success and well‐established foundations of PLS. For PLSCM, the optimization of model complexity and estimation of decision region can be performed as in multivariate calibration routines. Copyright © 2011 John Wiley & Sons, Ltd.
Transformation of the {Fe(NO)2}9 Dinitrosyl Iron Complexes (DNICs) into S‐Nitrosothiols (RSNOs) Triggered by Acid–Base Pairs
Authors: Tsou Chih‐Chin , Liaw Wen‐Feng
Published: October 2011

S‐Nitrosation of the coordinated thiolate of dinitrosyl iron complexes (DNICs) to generate S‐nitrosothiols (RSNOs) was demonstrated. Transformation of [{(NO)2Fe(μ‐StBu)}2] (1‐tBuS) into the {Fe(NO)2}9 DNIC [(NO)2Fe(StBu)(MeIm)] (2‐MeIm) occurs under addition of 20 equiv of 1‐methylimidazole (MeIm) into a solution of 1‐tBuS in THF. The dynamic interconversion between {Fe(NO)2}9 [(NO)2Fe(S‐NAP)(dmso)] (2‐dmso) (NAP=N‐acetyl‐D‐penicillamine) and [{(NO)2Fe(μ‐S‐NAP)}2] (1‐NAP) was also observed in a solution of complex 1‐NAP in DMSO. In contrast to the reaction of complex 2‐MeIm and bis(dimethylthiocarbamoyl) disulfide ((DTC)2) to yield {Fe(NO)}7 [(NO)Fe(DTC)2] (3) (DTC=S2CNMe2) accompanied by (tBuS)2 and NO(g), transformation of {Fe(NO)2}9 2‐MeIm (2‐dmso) into RSNOs (RS=tBuS, NAP‐S) along with complex 3 induced by the Brønsted acid solution of (DTC)2 demonstrated that Brønsted acid may play a critical role in triggering S‐nitrosation of the coordinated thiolate of DNICs 2‐MeIm (or 2‐dmso) to produce RSNOs. That is, DNIC‐mediated S‐nitrosation requires a Brønsted acid–Lewis base pair to produce RSNO. Transformation of DNICs into RSNOs may only occur on the one‐thiolate‐containing {Fe(NO)2}9 DNICs, in contrast to protonation of the two‐thiolate‐containing DNICs [(NO)2Fe(SR)2]− by Brønsted acid to yield [{(NO)2Fe(μ‐SR)}2]. These results might rationalize that the known protein‐Cys‐SNO sites derived from DNICs were located adjacent to acid and base motifs, and no protein‐bound SNO characterized to date has been directly derived from [protein–(cysteine)2Fe(NO)2] in biology.
Invasion triangle: an organizational framework for species invasion
Authors: Perkins Lora B. , Leger Elizabeth A. , Nowak Robert S.
Published: October 2011

Species invasion is a complex, multifactor process. To encapsulate this complexity into an intuitively appealing, simple, and straightforward manner, we present an organizational framework in the form of an invasion triangle. The invasion triangle is an adaptation of the disease triangle used by plant pathologists to help envision and evaluate interactions among a host, a pathogen, and an environment. Our modification of this framework for invasive species incorporates the major processes that result in invasion as the three sides of the triangle: (1) attributes of the potential invader; (2) biotic characteristics of a potentially invaded site; and (3) environmental conditions of the site. The invasion triangle also includes the impact of external influences on each side of the triangle, such as climate and land use change. This paper introduces the invasion triangle, discusses how accepted invasion hypotheses are integrated in this framework, describes how the invasion triangle can be used to focus research and management, and provides examples of application. The framework provided by the invasion triangle is easy to use by both researchers and managers and also applicable at any level of data intensity, from expert opinion to highly controlled experiments. The organizational framework provided by the invasion triangle is beneficial for understanding and predicting why species are invasive in specific environments, for identifying knowledge gaps, for facilitating communication, and for directing management in regard to invasive species.
CD8α+ and CD8α− DC subsets from BCG‐infected mice inhibit allergic Th2‐cell responses by enhancing Th1‐cell and Treg‐cell activity respectively
Authors: Gao Xiaoling , Bai Hong , Cheng Jianjun , Fan Yijun , Wang Shuhe , Jiao Lei , Xiu Nan , Yang Xi
Published: October 2011

The hygiene hypothesis has suggested an inhibitory effect of infections on allergic diseases, but the related mechanism remains unclear. We recently reported that DCs played a critical role in Mycobacterium bovis Bacille Calmette–Guérin (BCG)‐mediated inhibition of allergy, which depended on IL‐12 and IL‐10‐related mechanisms. Here, we tested the hypothesis that BCG infection could modulate the function of DC subsets, which might in turn inhibit allergic responses through different mechanisms. We sorted CD8α+ and CD8α− DCs from BCG‐infected mice and tested their ability to modulate Th2‐cell responses to ovalbumin (OVA) using in vitro and in vivo approaches. We found that both DC subsets could inhibit the allergic Th2‐cell response in both a DC:T‐cell co‐culture system and after adoptive transfer. These subsets exhibited different co‐stimulatory marker expression and cytokine production patterns and were different in inducing Th1 and Treg cells. Specifically, we found that CD8α+ DCs produced higher IL‐12, inducing higher Th1 cell response, while CD8α− DCs expressed higher ICOS‐L and produced higher IL‐10, inducing CD4+CD25+FoxP3+Treg cells with IL‐10 production and membrane‐bound TGF‐β expression. The finding suggests that one infection may inhibit allergy by both immune deviation and regulation mechanisms through modulation of DC subsets.
Synthesis of Hydrogen Polyoxides H2O4 and H2O3 and Their Characterization by Raman Spectroscopy
Authors: Levanov Alexander V. , Sakharov Dmitri V. , Dashkova Anna V. , Antipenko Ewald E. , Lunin Valeri V.
Published: October 2011

Hydrogen tetroxide (H2O4) and hydrogen trioxide (H2O3) have been prepared in relatively large quantities as components of peroxy radical condensates. The polyoxides were characterized by the Raman spectra of the oxygen framework. Lines at 500, 756, and 878 cm–1 correspond to skeletal oscillations of H2O3 in the condensate (OOO bend, asymmetric OO stretch, symmetric OO stretch). Lines at 449, 589, 624, 827, and 865 cm–1 match the skeletal vibrations of H2O4 (OOO bend 1, OOO bend 2, center OO stretch, asymmetric OO stretch, symmetric OO stretch). The line of the O4 torsion vibration of hydrogen tetroxide was not observed experimentally. The assignment was confirmed by B3LYP/6‐31+G(d,p) calculations of the vibrational spectra. According to the information available in the literature, this work is the only report of the preparation of H2O4 in significant concentrations and its Raman spectrum. For the first time convincing evidence is provided for the existence of hydrogen tetroxide (in low‐temperature solids).
Duodenal availability of conjugated linoleic acids after supplementation to dairy cow diets
Authors: Pappritz Julia , Lebzien Peter , Meyer Ulrich , Jahreis Gerhard , Kramer Ronny , Flachowsky Gerhard , Dänicke Sven
Published: October 2011

The objective of the present study was to investigate the effects of a lipid‐encapsulated CLA preparation on rumen metabolism and the actual post‐ruminal bioavailability of the applied CLA isomers. In the rumen, the CLA supplementation modified the molar proportions of VFA. In period CLA‐1 the rumen fermentation shifted toward more butyric acid at the expense of acetic acid. The highest CLA supplementation resulted in increased amounts of isobutyric, isovaleric, and valeric acid. The apparent ruminal digestibility of starch increased in period CLA‐2. The ruminal protein degradation was higher after CLA supplementation, while the efficiency of the use of the RDP for microbial protein synthesis declined. The duodenal flow of trans‐10,cis‐12 CLA amounted to 16 and 5% of the intake in periods CLA‐1 and CLA‐2, respectively. The transfer of trans‐10,cis‐12 CLA from duodenum into milk was 36 and 48% in periods CLA‐1 and CLA‐2, respectively. Overall, the observed effects of the supplementation of lipid‐encapsulated CLA on the parameters of rumen metabolism were negligible. The actual low post‐ruminal bioavailability of trans‐10,cis‐12 CLA suggest that most of the applied fat supplement was biohydrogenated.
Enantioselective Synthesis of Benzyl tert‐Butyl Sulfoxides
Authors: Syed Majid Khalil , Casey Mike
Published: October 2011

Enantiomerically pure benzyl sulfoxides are effective tools for the formation of new C–C bonds with control of configuration at new stereogenic centres. The reaction of enantioenriched tert‐butyl tert‐butanethiosulfinate with benzyllithium derivatives, obtained by deprotonation of the corresponding toluene derivatives, gave a wide variety of benzyl tert‐butyl sulfoxides with complete inversion of configuration. The benzyl sulfoxides were deprotonated in situ, and addition of the electrophiles gave α‐substituted products with good diastereoselectivity.
Synthesis of Thiazoline–Oxazoline Ligands and Their Application in Asymmetric Catalysis
Authors: McKeon Seán C. , Müller‐Bunz Helge , Guiry Patrick J.
Published: October 2011

A series of novel ligands incorporating oxazoline and thiazoline units were synthesized in high yield by employing a convergent route, in which the key step is a microwave‐assisted palladium‐catalyzed aryl amination. The new ligands were tested in the zinc‐catalyzed Friedel–Crafts alkylation of indole with trans‐β‐nitrostyrene, inducing enantiomeric excess values of up to 69 %. The complete series of these ligands was also applied to the chromium‐catalyzed Nozaki–Hiyama–Kishi (NHK) allylation of benzaldehyde, affording enantiomeric excess values of up to 85 %. A crystal structure of the most successful ligand in this transformation bound to iron(III) was obtained and demonstrated a tridentate binding mode of the ligand. A transition state is proposed to account for the preferential formation of the (R)‐enantiomer in the NHK reaction.
Reduced Graphene Sheets Modified Electrodes for Electrochemical Detection of Sulfide
Authors: Qi Peng , Wan Yi , Zhang Dun , Wu Jiajia
Published: October 2011

This paper describes a new electrochemical sensor based on reduced graphene sheets (RGSs) modified glassy carbon electrodes for rapid detection of sulfide. The morphology and electrochemical properties of the RGSs are characterized by atomic force microscopy and cyclic voltammetry. The effects of the scan rates and pH are investigated to evaluate the oxidation processes. Analytical performances of RGSs modified electrodes for direct determination of sulfide in phosphate buffer solutions (PBSs) are also assessed. The RGSs are shown to be viable potential material for sulfide detection as shown by their electrochemical performance.
Ultrafast, efficient separations of large‐sized dsDNA in a blended polymer matrix by microfluidic chip electrophoresis: A design of experiments approach
Authors: Sun Mingyun , Lin Jennifer S. , Barron Annelise E.
Published: October 2011

Double‐stranded (ds) DNA fragments over a wide size range were successfully separated in blended polymer matrices by microfluidic chip electrophoresis. Novel blended polymer matrices composed of two types of polymers with three different molar masses were developed to provide improved separations of large dsDNA without negatively impacting the separation of small dsDNA. Hydroxyethyl celluloses with average molar masses of ∼27 kDa and ∼1 MDa were blended with a second class of polymer, high‐molar mass (∼7 MDa) linear polyacrylamide. Fast and highly efficient separations of commercially available DNA ladders were achieved on a borosilicate glass microchip. A distinct separation of a 1‐kb DNA extension ladder (200–40 000 bp) was completed in 2 min. An orthogonal design of experiments was used to optimize experimental parameters for DNA separations over a wide size range. We find that the two dominant factors are the applied electric field strength and the inclusion of a high concentration of low‐molar mass polymer in the matrix solution. These two factors exerted different effects on the separations of small dsDNA fragments below 1 kbp, medium dsDNA fragments between 1 and 10 kbp, and large dsDNA fragments above 10 kbp.
An Examination of the Ravello Profile — A Neuropsychological Test Battery for Anorexia Nervosa
Authors: Stedal Kristin , Frampton Ian , Landrø Nils Inge , Lask Bryan
Published: October 2011

The Ravello Profile test battery was developed to ensure a consistent methodology when researching neuropsychological functioning in anorexia nervosa (AN). To date, 157 patients with AN have been assessed with the full Ravello Profile. The present review is the first study to systematically investigate the tests included in the battery. Fifteen experimental studies, comparing AN patients with healthy control participants on at least one of the Ravello Profile tests, were identified, and effect sizes were calculated. Three of the tests, Verbal Fluency Test (VFT), Rey Complex Figure Test (RCFT) and Trail Making Test (TMT), were meta‐analysed, and the pooled standardized effect size was significant for all three tests (0.25, −0.68 and 0.49, respectively). Patients with AN performed significantly better than healthy control participants on assessment of verbal fluency (VFT) and worse on tests of visual memory (RCFT) and set‐shifting (TMT). The Ravello Profile test battery appears to consist of tests that are appropriate for assessing characteristic neuropsychological profiles specific in AN. Copyright © 2011 John Wiley & Sons, Ltd and Eating Disorders Association.
The problem of control and the role of home–host ties in explaining multinationals' foreign operations, competitiveness, and performance
Authors: Rangan Subramanian , Drummond Aldemir
Published: October 2011

The existing multinational enterprise (MNE) literature has focused on capabilities and value creation challenges, including related to cultural and other distance. To better understand heterogeneity in the foreign country performance of MNEs, however, we need to go beyond the global strategy challenges of capabilities and coordination. Specifically, we need to explore MNEs' value capture challenges abroad and attend to control as a chronic dilemma that is inadequately addressed by internalization. In operating in foreign host countries, MNEs are chronically exposed to two types of largely uninsurable discretion: sovereign discretion of host governments and delegated discretion of host country employees, partners, suppliers, and such. The problem in the first case relates to power; and in the second it relates to information. Power and information are the sine qua non of effective control. Control is a prerequisite for anticipated value capture, which influences the extent of MNEs' capability transfer, input localization, and output adaptation in a given host country. Transfer, localization, and adpatation are the essence of host country value creation, which influences competitiveness and performance there. Accordingly, beyond differences in MNE capabilities, heterogeneity in access to credible power and reliable information in a focal host country predicts heterogeneity in MNEs' competitiveness and relative performance there. This is why and how heterogeneity in macro‐level home–host ties (HHTs) explains durable performance differences among foreign MNEs operating in a focal host country. In terms of global strategy research and practice, this turns the spotlight on macro‐level HHTs, nonmarket strategy, and, eventually, focused internationalization. It also argues for more microfoundations research on the limits and actual control benefits of internalization.
Permeability to inter‐ and intrafirm knowledge flows: the role of coordination and hierarchy in MNEs
Authors: Anand Jaideep
Published: October 2011

Multinational enterprises (MNEs) actively participate in both inter‐ and intrafirm knowledge flows. But what distinguishes intrafirm knowledge flows from those across firms? Are they essentially the same with ‘more of it’ going on intrafirm, or is there a fundamental qualitative difference between the two? This research sheds light on this issue by empirically comparing the evolution of intra– and interfirm knowledge flows using patent citations. Specifically, I study the integration of greenfield and acquired subsidiaries in the external and internal contexts of the firm over time. Not only is the development of intrafirm knowledge flows affected by the greater coordination within the firm, the existence of hierarchy enables asymmetric knowledge flows within the firm. Consequently intrafirm knowledge flows in contrast to interfirm flows, can be one‐sided and not conditioned by reciprocity. In terms of practical implications, these results reveal that acquired subsidiaries become less connected with external knowledge over time, indicating that they achieve greater internal integration at the expense of their external integration. The evolution of greenfield units does not reveal such an internal‐external trade‐off. This study suggests major differences between the mechanisms of intra‐ and interfirm knowledge flows, and highlights the role of coordination and hierarchy as key determinants of intrafirm knowledge flows, MNE strategies, and innovation.
Internationalization revisited: the big step hypothesis
Authors: Pedersen Torben , Shaver J. Myles
Published: October 2011

We refine internationalization theory by hypothesizing that international expansion is a discontinuous process characterized by an initial ‘big step.’ Firms have to build an infrastructure (e.g., architecture, management systems, and mind‐set) to support international operations the first time they venture abroad, and subsequent international operations are able to leverage this infrastructure. Thus, we hypothesize that the internationalization process is characterized by: (1) firms taking a long period to make their first international investment; and (2) firms taking shorter but constant periods for subsequent investments. We examine the international expansion activities of 176 Danish firms and find support for these arguments.
Global strategy and the collaboration of MNEs, NGOs, and governments for the provisioning of collective goods in emerging markets
Authors: Boddewyn Jean , Doh Jonathan
Published: October 2011

The global business environment is increasingly characterized by dynamic collaborations among public as well as private for‐profit and not‐for‐profit actors for the provision in emerging markets of such local public goods as health, education, transportation, and utilities whose supply has received scant attention in international business research. Drawing from, and expanding on, transaction‐cost economics and institutional theory, we analyze the choice of collaborative arrangements among the three parties for the local supply of these public goods—here, called a ‘collective goods’ via contracting, alliance, internationalization or assistance—the latter a governance mode hitherto overlooked in transaction‐cost economics but essential in dealing with collective goods and nonmarket actors. We discuss the implications of these arrangements for multinational enterprise nonmarket strategies within the realm of global strategy.
Cell of origin fails to predict survival in patients with diffuse large B‐cell lymphoma treated with autologous hematopoietic stem cell transplantation
Authors: Gu Keni , Weisenburger Dennis D , Fu Kai , Chan Wing C , Greiner Timothy C , Aoun Patricia , Smith Lynette M , Bast Martin , Liu Zhongfen , Bociek R. Gregory , Bierman Philip J , Armitage James O , Vose Julie M
Published: October 2011

Diffuse large B‐cell lymphoma (DLBCL) includes two prognostically important subtypes, the germinal center B‐cell (GCB) and the non‐GCB types. The aim of this study was to evaluate immunohistochemical approaches for predicting the survival of patients with DLBCL following autologous hematopoietic stem cell transplantation (AHSCT). We identified 62 patients with DLBCL who either had an initial complete remission (17 patients) or received salvage chemotherapy for relapsed or refractory disease (45 patients), followed by AHSCT. Tissue microarrays were immunostained with monoclonal antibodies against GCET1, CD10, BCL6, MUM1, FOXP1 and LMO2. Using the Hans algorithm, we classified 50% of the cases as GCB type, whereas the Choi algorithm classified 58% as GCB type and LMO2 was positive in 69%. However, no significant differences were found in the 5‐year overall or event‐free survivals using any of these approaches. In conclusion, cell of origin fails to predict survival of DLBCL patients treated with AHSCT. Copyright © 2011 John Wiley & Sons, Ltd.
Weaknesses and Challenges of Primary Healthcare System in Iran: A Review
Authors: Moghadam Mahmoud Nekoei , Sadeghi Vahideh , Parva Sahar
Published: October 2011

While the primary healthcare (PHC) services in Iran were appropriate to the needs of the population in the late 1970s and 1980s, the changing burden of disease and shifting demand patterns have rendered the existing PHC system no longer suitable for meeting current and emergent needs. This has serious implications for the PHC system in Iran, which has clearly succeeded in addressing high levels of communicable diseases, maternal deaths and infant mortality, but appears less well prepared to address the emerging challenges of noncommunicable diseases (NCD).

We conducted a systematic review of the available literature in the past 10 years related to the PHC system in Iran to assess its weaknesses and challenges.

This paper categorizes PHC system weaknesses from the studied articles into two groups: (i) those related to the key functions of PHC, and (ii) others, which refer to health system weaknesses existing with the current PHC model.

Iran can draw on international experience and evidence regarding interventions, which can be used to develop an effective and responsive PHC system designed to address current and emerging needs, in particular the NCD burden. Copyright © 2011 John Wiley & Sons, Ltd.
A novel synthesis of [2‐14C]2,5‐dichloropyrimidine
Authors: Tran Scott B. , Maxwell Brad D. , Wu Hong , Bonacorsi Samuel J.
Published: October 2011

[2‐14 C]2,5‐dichloropyrimidine is a useful reagent for labeling biologically active compounds for use in hepatocyte transport studies, protein covalent binding, and metabolic profiling. This paper describes a novel five‐step synthesis of [2‐14 C]2,5‐dichloropyrimidine from readily available [14C]urea by way of a boronic acid intermediate. A total of 4.34 mCi of [2‐14 C]2,5‐dichloropyrimidine was obtained with a specific activity of 226.0 μCi/mg (33.7 mCi/mmol). The radiochemical purity was 95.8%, and the overall radiochemical yield was 22% based on 20 mCi of [14C]urea starting material. Copyright © 2011 John Wiley & Sons, Ltd.
Characterization of the volatile profile of Antarctic bacteria by using solid‐phase microextraction‐gas chromatography‐mass spectrometry
Authors: Romoli Riccardo , Papaleo Maria Cristiana , de Pascale Donatella , Tutino Maria Luisa , Michaud Luigi , LoGiudice Angelina , Fani Renato , Bartolucci Gianluca
Published: October 2011

Bacteria belonging to the Burkholderia cepacia complex (Bcc) are significant pathogens in Cystic Fibrosis (CF) patients and are resistant to a plethora of antibiotics. In this context, microorganisms from Antarctica are interesting because they produce antimicrobial compounds inhibiting the growth of other bacteria. This is particularly true for bacteria isolated from Antarctic sponges. The aim of this work was to characterize a set of Antarctic bacteria for their ability to produce new natural drugs that could be exploited in the control of infections in CF patients by Bcc bacteria. Hence, 11 bacterial strains allocated to different genera (e.g., Pseudoalteromonas, Arthrobacter and Psychrobacter) were tested for their ability to inhibit the growth of 21 Bcc strains and some other human pathogens. All these bacteria completely inhibited the growth of most, if not all, Bcc strains, suggesting a highly specific activity toward Bcc strains. Experimental evidences showed that the antimicrobial compounds are small volatile organic compounds, and are constitutively produced via an unknown pathway. The microbial volatile profile was obtained by SPME‐GC‐MS within the m/z interval of 40–450. Solid phase micro extraction technique affords the possibility to extract the volatile compounds in head space with a minimal sample perturbation. Principal component analysis and successive cluster discriminant analysis was applied to evaluate the relationships among the volatile organic compounds with the aim of classifying the microorganisms by their volatile profile. These data highlight the potentiality of Antarctic bacteria as novel sources of antibacterial substances to face Bcc infections in CF patients. Copyright © 2011 John Wiley & Sons, Ltd.
Enzymatic large‐scale production of biodiesel
Authors: Nielsen Per Munk , Rancke‐Madsen Anders
Published: October 2011

Enzymatic production of biodiesel has been the subject of intensive research over the last 5‐10 years. When comparing the economy of enzymatic and chemical produced biodiesel important factors include yield, flexibility in feedstock, value of by‐products, recovery costs for alcohol as well as the cost of enzyme, enzyme lifetime, reaction time are important factors. By 2009 large‐scale enzymatic biodiesel was considered to be cost effective [1]. Since then development work has further improved the technology which is now ready for the market. We have developed a full enzymatic two‐step process for converting oils to biodiesel, and a pretreatment unit which can be installed in an existing chemical biodiesel plant to enable it to process high free fatty acid feedstocks.
Oligo(glycerol) Methacrylate Macromonomers
Authors: Thomas Anja , Wolf Florian K. , Frey Holger
Published: October 2011

Linear, protected ω‐methoxy oligo(glycerol) methacrylate (OGlyPMA) macromonomers are synthesized via anionic ring‐opening polymerization of ethoxyethyl glycidyl ether (EEGE) followed by termination with methacrylic acid anhydride ( = 3–11, PDI < 1.30). The covalently bound methacrylate moiety allows the homopolymerization of OGlyPMA as well as copolymerization with low molecular weight comonomers. In homopolymerizations, macromonomers are polymerized by atom transfer radical polymerization (ATRP) yielding well‐defined graft polymers ( = 20 000–30 000 g mol−1). Acidic hydrolysis of the protecting groups releases water‐soluble polyhydroxy‐functional structures. First results on the copolymerization with 2‐hydroxyethyl methacrylate (HEMA) are given in the final part of this work.
Bounding reward measures of Markov models using the Markov decision processes
Authors: Buchholz Peter
Published: October 2011

For a Markov reward process, where upper and lower bounds for the transition rates and rewards are known, a new approach to bound the expected reward is presented. Based on a previous paper where sharp bounds have been defined for the problem, but only an inefficient and unstable algorithm is proposed, this paper presents algorithms to compute the bounds by interpreting the problem as a Markov Decision Process. In this way, the well known value and policy iteration algorithms can be adopted to compute reward bounds in a stable and fairly efficient way. Different numerical techniques are presented for computing the reward bounds. Copyright © 2011 John Wiley & Sons, Ltd.
Fast multilevel methods for Markov chains
Authors: Sterck Hans De , Miller Killian , Treister Eran , Yavneh Irad
Published: October 2011

This paper describes multilevel methods for the calculation of the stationary probability vector of large, sparse, irreducible Markov chains. In particular, several recently proposed significant improvements to the multilevel aggregation method of Horton and Leutenegger are described and compared. Furthermore, we propose a very simple improvement of that method using an over‐correction mechanism. We also compare with more traditional iterative methods for Markov chains such as weighted Jacobi, two‐level aggregation/disaggregation, and preconditioned stabilized biconjugate gradient and generalized minimal residual method. Numerical experiments confirm that our improvements lead to significant speedup, and result in multilevel methods that are competitive with leading iterative solvers for Markov chains. Copyright © 2011 John Wiley & Sons, Ltd.
On eigenvalue distribution of constraint‐preconditioned symmetric saddle point matrices
Authors: Bergamaschi Luca
Published: October 2011

This paper is devoted to the analysis of the eigenvalue distribution of two classes of block preconditioners for the generalized saddle point problem. Most of the bounds developed improve those appeared in previously published works. Numerical results onto a realistic test problem give evidence of the effectiveness of the estimates on the spectrum of preconditioned matrices. Copyright © 2011 John Wiley & Sons, Ltd.
Numerical Solution of Markov Chains
Authors: Benzi Michele
Published: October 2011

This special issue contains a selection of papers from the Sixth International Workshop on the Numerical Solution of Markov Chains, held in Williamsburg, Virginia on September 16–17, 2010. The papers cover a broad range of topics including perturbation theory for absorbing chains, bounding techniques, steady‐state and transient solution methods, multilevel algorithms, preconditioning, and applications. Copyright © 2011 John Wiley & Sons, Ltd.
Comment on ‘Preconditioning of matrices partitioned in 2 Œ 2 block form: Eigenvalue estimates and Schwarz DD for mixed FEM’ by Owe Axelsson, Radim Blaheta
Authors: Cao Zhi‐Hao
Published: October 2011

In this note, we discuss the inverse representations of regularized saddle point matrices and point out that some conclusions given by Axelsson and Blaheta in [Numerical Linear Algebra with Applications, 2010,17:787–810 ] are not true.Copyright © 2011 John Wiley & Sons, Ltd.
Preconditioning for partial differential equation constrained optimization with control constraints
Authors: Stoll Martin , Wathen Andy
Published: October 2011

Optimal control problems with partial differential equations play an important role in many applications. The inclusion of bound constraints for the control poses a significant additional challenge for optimization methods. In this paper, we propose preconditioners for the saddle point problems that arise when a primal–dual active set method is used. We also show for this method that the same saddle point system can be derived when the method is considered as a semismooth Newton method. In addition, the projected gradient method can be employed to solve optimization problems with simple bounds, and we discuss the efficient solution of the linear systems in question. In the case when an acceleration technique is employed for the projected gradient method, this again yields a semismooth Newton method that is equivalent to the primal–dual active set method. We also consider the Moreau–Yosida regularization method for control constraints and efficient preconditioners for this technique. Numerical results illustrate the competitiveness of these approaches. Copyright © 2011 John Wiley & Sons, Ltd.