bluuebunny/crossref_metadata_2025 huggingface dataset:
Noble‐Metal Nanocrystals with Concave Surfaces: Synthesis and Applications
Authors: Zhang Hui , Jin Mingshang , Xia Younan
Published: May 2012

Metal nanocrystals with concave surfaces are interesting for a wide variety of applications that are related to catalysis, plasmonics, and surface‐enhanced spectroscopy. This interest arises from their high‐index facets, surface cavities, and sharp corners/edges. Two major challenges are associated with this novel class of nanocrystals: 1) how to generate a concave surface with negative curvature, which is not favored by thermodynamics owing to its higher energy than the convex counterpart; and 2) how to stabilize the morphology of a nanocrystal with concave structures on the surface. Recently, a number of different procedures have been developed for the synthesis of noble‐metal nanocrystals with concave surfaces. This Review provides a brief account of these developments, with the aim of offering new insights into the growth mechanisms. We focus on methods based on two general strategies: 1) site‐specific dissolution through etching and galvanic replacement; and 2) directionally controlled overgrowth by facet‐selective capping, kinetic control, and template‐directed epitaxy. Their enhanced catalytic and electrocatalytic properties are also described.
Small and Medium‐Sized Enterprises and Sustainability: Managers' Values and Engagement with Environmental and Climate Change Issues
Authors: Williams Sarah , Schaefer Anja
Published: May 2012

This article reports on an in‐depth, qualitative study into the pro‐environmental engagement of small businesses in the east of England, with respect to climate change in particular. Managers of environmentally pro‐active small businesses were asked about the pro‐environmental measures they had implemented in their firms, their motivations for doing so, and their understanding of climate change. The managers in this study had a relatively good understanding of environmental issues in general and climate change in particular, and had implemented a range of pro‐environmental measures in their firms. Their understanding of climate change was a holistic one, which sat within their overall understanding of environmental and social issues. While economic arguments and external pressure played a role in their pro‐environmental engagement, perhaps the most notable motivation for managers in this study to engage with environmental and climate change issues was personal values and beliefs. Environmentally engaged managers exhibited an internal locus of control. Some of these findings contrast with the views of key informants in local government and business advice organisations, who tend to emphasise the business case and cost arguments when trying to encourage small businesses towards greater environmental engagement. These findings suggest that public policy and business advice in this area should perhaps focus more strongly on personal values and a sense of being able to contribute to environmental protection in their engagement with small businesses. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment.
Interactive coupling between a tree and raindrops
Authors: Yang Meng , Jiang Longsheng , Li Xiaosheng , Liu Youquan , Liu Xuehui , Wu Enhua
Published: May 2012

This paper presents a novel approach for simulating the dynamic coupling between a tree and raindrops based on physical deformation and fluid simulation. By the approach, tree animation in the rain can be simulated in a two‐resolution way: branch motion and leaf motion. The branch is represented by the Euler–Bernoulli beam model, and the leaf petiole is represented by the three‐prism elastic model. Interaction coupling liquid motion on the hydrophilic surface with a flexible petiole is well implemented by a special design. To simplify the computation process, instead of the computation‐intensive three‐dimensional Navier–Stokes equations, shallow water equations are used to simulate the water dynamics together with the whole leaf deformation. Simulation has been also made to various phenomena incurred from the interactive coupling. These include, among others, part of impacting raindrops splashing into the air with the remaining flowing along the slant of the leaf and merging into larger ones or hanging on the blade boundary, with the leaf rebounding and vibrating after the drops fall off the leaf. A level‐of‐detail approach is exploited to accelerate rendering in views of different distances. The experimental results illustrate that the approach can be applied to efficiently generate realistic details of the interactive coupling between a tree and raindrops. Copyright © 2012 John Wiley & Sons, Ltd.
Cellular Uptakes, Biostabilities and Anti‐miR‐210 Activities of Chiral Arginine‐PNAs in Leukaemic K562 Cells
Authors: Manicardi Alex , Fabbri Enrica , Tedeschi Tullia , Sforza Stefano , Bianchi Nicoletta , Brognara Eleonora , Gambari Roberto , Marchelli Rosangela , Corradini Roberto
Published: May 2012

A series of 18‐mer peptide nucleic acids (PNAs) targeted against micro‐RNA miR‐210 was synthesised and tested in a cellular system. Unmodified PNAs, R8‐conjugated PNAs and modified PNAs containing eight arginine residues on the backbone, either as C2‐modified (R) or C5‐modified (S) monomers, all with the same sequence, were compared. Two different models were used for the modified PNAs: one with alternated chiral and achiral monomers and one with a stretch of chiral monomers at the N terminus. The melting temperatures of these derivatives were found to be extremely high and 5 M urea was used to assess differences between the different structures. FACS analysis and qRT‐PCR on K562 chronic myelogenous leukaemic cells indicated that arginine‐conjugated and backbone‐modified PNAs display good cellular uptake, with best performances for the C2‐modified series. Resistance to enzymatic degradation was found to be higher for the backbone‐modified PNAs, thus enhancing the advantage of using these derivatives rather than conjugated PNAs in the cells in serum, and this effect is magnified in the presence of peptidases such as trypsin. Inhibition of miR‐210 activity led to changes in the erythroid differentiation pathway, which were more evident in mithramycin‐treated cells. Interestingly, the anti‐miR activities differed with use of different PNAs, thus suggesting a role of the substituents not only in the cellular uptake, but also in the mechanism of miR recognition and inactivation. This is the first report relating to the use of backbone‐modified PNAs as anti‐miR agents. The results clearly indicate that backbone‐modified PNAs are good candidates for the development of very efficient drugs based on anti‐miR activity, due to their enhanced bioavailabilities, and that overall anti‐miR performance is a combination of cellular uptake and RNA binding.
Species‐Specific Activity of Glycolipid Ligands for Invariant NKT Cells
Authors: Dangerfield Emma M. , Cheng Janice M. H. , Knight Deborah A. , Weinkove Robert , Dunbar P. Rod , Hermans Ian F. , Timmer Mattie S. M. , Stocker Bridget L.
Published: May 2012

The immunomodulatory glycolipid α‐galactosylceramide (α‐GalCer) binds to CD1d and exhibits potent activity as a ligand for invariant CD1d‐restricted natural killer‐like T cells (iNKT cells). Structural analogues of α‐GalCer have been synthesised to determine which components are required for CD1d presentation and iNKT cell activation, however, to date the importance of the phytosphingosine 4‐hydroxyl for iNKT cell activation has been disputed. To clarify this, we synthesised two 4‐deoxy α‐GalCer analogues (sphinganine and sphingosine) and investigated their ability to activate murine and human iNKT cells. Analysis revealed that the analogues possessed comparable activity to α‐GalCer in stimulating murine iNKT cells, but were severely compromised in their ability to stimulate human iNKT cells. Here we determined that species‐specific glycolipid activity was due to a lack of recognition of the analogues by the T‐cell receptors on human iNKT cells rather than insufficient presentation of the analogues on human CD1d molecules. From these results we suggest that glycolipids developed for potent iNKT cell activity in humans should contain a phytosphingosine base.
ChemInform Abstract: 2Mg(OH)2·MgCl2·2H2O and 2Mg(OH)2·MgCl2·4H2O, Two High Temperature Phases of the Magnesia Cement System.
Authors: Dinnebier Robert E. , Oestreich Melanie , Bette Sebastian , Freyer Daniela
Published: May 2012

The title materials exist as stable phases in the MgO—MgCl2—H2O system at 120 °C.
ChemInform Abstract: On the Rare Earth Metal Bismuthide Oxides RE2BiO2 (RE: Nd, Tb, Dy, Ho).
Authors: Nuss Juergen , Jansen Martin
Published: May 2012

The new dark grey metallic compounds Nd2BiO2, Tb2BiO2, Dy2BiO2, and Ho2BiO2 are synthesized in ≈1 g batches by solid state reaction of elemental Bi, LnBi (Ln: Nd, Tb, Dy, Ho), and Ln2O3 (sealed Ta ampules, 1770 K, 72 h).
ChemInform Abstract: Synthesis, Characterization, and Computational Study of WSF4·NC5H5.
Authors: Nieboer Jared , Yu Xin , Chaudhary Praveen , Mercier Helen P. A. , Gerken Michael
Published: May 2012

The new Lewis acid/base adduct of title is obtained from WSF4 and pyridine at room temperature (yield given in g) and characterized by single crystal XRD, Raman and NMR spectroscopy, and DFT calculations.
ChemInform Abstract: Direct Titanium‐Mediated Conversion of Ketones into Enamides with Ammonia and Acetic Anhydride.
Authors: Reeves Jonathan T. , et al. et al.
Published: May 2012

The method is performed with safe and inexpensive reagents, proceeds under mild conditions, and tolerates diverse functional groups.
ChemInform Abstract: Reactions of Sulfur‐ and Phosphorus‐Substituted Fluoroalkylating Silicon Reagents with Imines and Enamines under Acidic Conditions.
Authors: Kosobokov Mikhail D. , Dilman Alexander D. , Struchkova Marina I. , Belyakov Pavel A. , Hu Jinbo
Published: May 2012

The title reaction allows an effective access to diverse fluorinated amines of biological interest.
ChemInform Abstract: Aqueous and Biphasic Nitrile Hydration Catalyzed by a Recyclable Ru(II) Complex under Atmospheric Conditions.
Authors: Lee Wei‐Chih , Frost Biran J.
Published: May 2012

Aqueous phase nitrile hydration results in near quantitative conversion of aliphatic and aromatic nitriles (I) and (III) into amides (II) and (IV).
ChemInform Abstract: Chemoselective Deprotection of Aryl tert‐Butyldimethylsilyl Ethers Promoted by Phosphates.
Authors: Yan Lin , Zhao Fangli , Gan Yin , Zhao Jin , Jiang Zhiyong
Published: May 2012

Tbs functions at the aromatic moiety are deprotected selectively under conditions A).
ChemInform Abstract: Ruthenium‐Catalyzed Oxidative C—H Alkenylations of Anilides and Benzamides in Water.
Authors: Ackermann Lutz , Wang Lianhui , Wolfram Ratnakancana , Lygin Alexander V.
Published: May 2012

Starting from the fluorinated benzamide (X), the lactams (XI) and (XII) are obtained.
ChemInform Abstract: Synthesis and Cross‐Coupling Reactions of Imidomethyltrifluoroborates with Aryl Chlorides.
Authors: Devulapally Rammohan , Fleury‐Bregeot Nicolas , Molander Gary A. , Seapy Dave G.
Published: May 2012

The reaction is conveniently achieved by Suzuki—Miyaura‐like cross‐coupling with trifluoroborate (III), which is easily prepared by an optimized procedure.
ChemInform Abstract: Chiral Broensted Acid Catalyzed Enantioselective Propargylation of Aldehydes with Allenylboronate.
Authors: Reddy Leleti Rajender
Published: May 2012

The organocatalytic reaction is practical and quite general with a broad substrate scope covering aryl, polyaryl, heteroaryl, and aliphatic aldehydes.
ChemInform Abstract: A Cyclobutene‐1,2‐bis(imidazolium) Salt as Preligand for Palladium‐Catalyzed Cross‐Coupling Reactions: Properties and Applications.
Authors: Rahimi Alireza , Papai Imre , Madarasz Adam , Gjikaj Mimoza , Namyslo Jan C. , Schmidt Andreas
Published: May 2012

The title salt forms mono‐ and bis‐carbenes on treatment with bases, which serve as efficient ligands in room‐temperature Suzuki—Miyaura reactions, C—C couplings to form sterically extremely hindered biaryls, selective thiophene arylations and couplings with vinylic chlorides.
ChemInform Abstract: Aminoborylation/Suzuki—Miyaura Tandem Cross Coupling of Aryl Iodides as Efficient and Selective Synthesis of Unsymmetrical Biaryls.
Authors: Marciasini Ludovic , Richy Nicolas , Vaultier Michel , Pucheault Mathieu
Published: May 2012

Sequential borylation of a first aryl iodide (I) using a dialkylaminoborane followed by a Suzuki—Miyaura cross coupling of second aryl iodide (II) affords unsymmetrical biaryls, in an efficient and practical manner.
ChemInform Abstract: Synthesis of 3,3‐Disubstituted α‐Tetralones by Rhodium‐Catalyzed Reaction of 1‐(2‐Haloaryl)cyclobutanols.
Authors: Ishida Naoki , Sawano Shota , Murakami Masahiro
Published: May 2012

The asymmetric version of the title reaction affords chiral α‐tetralones bearing an asymmetric quaternary carbon at the 3‐position.
ChemInform Abstract: Effective Synthesis of 2,5‐Disubstituted Tetrahydrofurans from Glycerol by Catalytic Alkylation of Ketones.
Authors: Rueping Magnus , Phapale Vilas B.
Published: May 2012

The iridium‐catalyzed α‐alkylation of ketones (II) and (VI) followed by reduction and application of a Fe(III)‐mediated deprotection/cyclization methodology affords an isomeric mixture of tetrahydrofurans (IV)/(V) and (VIII).
ChemInform Abstract: A Simple Direct Phosgeneless Route to N‐Heteroaryl Unsymmetrical Ureas.
Authors: Carafa Marianna , Mele Valentina , Quaranta Eugenio
Published: May 2012

The approach to ureas (III), (V), and (VII) involves the direct reaction of N‐phenoxycarbonyl derivatives of pyrrole, indole, and carbazole, (I), (IV), and (VI), with amines (II) in the presence of an amidine base under very mild conditions.
ChemInform Abstract: Synthesis of 2‐Iminoindolines via Samarium Diiodide Mediated Reductive Cyclization of Carbodiimides.
Authors: Ishida Takayuki , Tsukano Chihiro , Takemoto Yoshiji
Published: May 2012

A synthetic method for the preparation of 2‐iminoindolines via SmI2‐mediated reductive cyclization of carbodiimides bearing unsaturated carbonyl groups such as lactams or esters (cyclic or acyclic) is described.
ChemInform Abstract: Synthesis and Bioevaluation of Novel 3,4,5‐Trimethoxybenzylbenzimidazole Derivatives that Inhibit Helicobacter pylori‐Induced Pathogenesis in Human Gastric Epithelial Cells.
Authors: Lai Chih‐Ho , et al. et al.
Published: May 2012

Among the title compounds (VIII) (28 examples) synthesized, compound (VIIIf) is found to be the most potent one in the inhibition of H.pylori growth and pathogenesis of host cells.
ChemInform Abstract: Palladium(II)‐Catalyzed Enantioselective Synthesis of 2‐Vinyl Oxygen Heterocycles.
Authors: Cannon Jeffrey S. , Olson Angela C. , Overman Larry E. , Solomon Nicole S.
Published: May 2012

Catalysts (I) and (II) efficiently promote the enantioselective rearrangement of (E)‐alkenylated phenols to 2‐vinyl oxygen heterocycles.
ChemInform Abstract: Suzuki—Miyaura Reactions of the Bis(triflates) of 1,3‐ and 1,4‐Dihydroxythioxanthone. Electronic and Steric Effects on the Site‐Selectivity.
Authors: Zinad Dhafer Saber , Feist Holger , Villinger Alexander , Langer Peter
Published: May 2012

A convenient and regioselective method for the synthesis of a variety of arylated thioxanthones is presented.
ChemInform Abstract: Three‐Component Coupling Sequence for the Regiospecific Synthesis of Substituted Pyridines.
Authors: Chen Ming Z. , Micalizio Glenn C.
Published: May 2012

The de novo synthesis proceeds through the nucleophilic addition of a dithiane anion to an α,β‐unsaturated aldehyde or ketone, followed by the Ti‐mediated carbometalation of the lithium alkoxides derived from the resulting alcohols (III) with Tms‐imines (generated in situ by the low‐temperature reaction of LiN(Tms)2 with an aldehyde), and the Hg(II)‐ or Ag(I)‐mediated ring closure.
ChemInform Abstract: Synthesis of Polysubstituted Pyridines under Combined Microwave and Ultrasound Irradiation: K2CO3‐Promoted Tandem Addition/Cyclization/Hydrogen Shift Process.
Authors: Feng Huangdi , Li Yuan , Van der Eycken Erik V. , Peng Yanqing , Song Gonghua
Published: May 2012

The multicomponent reaction, efficiently achieved under optimized conditions A), allows an interesting access to pyridine structures of type (IV).
ChemInform Abstract: Construction of Dihydropyrimidine Skeleton Using 1,2,4‐Trisubstituted‐1,3‐diaza‐1,3‐butadienes.
Authors: Cho Hidetsura , Nishimura Yoshio , Yasui Yoshizumi , Yamaguchi Masahiko
Published: May 2012

Cyclization of substrates (I) with activated olefins results in formation of tetrahydropyrimidines together with varying ratios of 1,6‐dihydropyrimidines.
ChemInform Abstract: One‐Pot Synthesis of 2H‐Pyrano[2,3‐d]pyrimidine Derivatives.
Authors: Bayat Mohammad , Bayat Yadollah , Asayes Soheila Shafei
Published: May 2012

A new synthetic strategy for 2H‐pyrano[2,3‐d]pyrimidines (III) is described including proposal of a possible reaction mechanism.
ChemInform Abstract: Microwave‐Promoted Catalyst‐ and Solvent‐Free Aza‐Diels—Alder Reaction of Aldimines with 6‐[2‐(Dimethylamino)vinyl]‐1,3‐dimethyluracil.
Authors: Sarma Rupam , Sarmah Manas M. , Prajapati Dipak
Published: May 2012

The title reaction allows an efficient access to pyridopyrimidines of type (III) and (IV).
ChemInform Abstract: Synthesis of 6‐Substituted 6‐Nitroperhydro‐1,4‐diazepines via Novel Tandem Retro‐Henry and Mannich/Michael Reactions.
Authors: Martinelli Jonathan , Gugliotta Giuseppe , Tei Lorenzo
Published: May 2012

Reduction of the nitro group allows formation of the corresponding amino derivatives.
ChemInform Abstract: Two New Terpenoids from Endophytic Fungus Periconia sp. F‐31.
Authors: Ge Han‐Lin , Zhang De‐Wu , Li Li , Xie Dan , Zou Jian‐Hua , Si Yi‐Kang , Dai Jungui
Published: May 2012

The two new terpenoids, (+)‐periconone A (I) and (‐)‐2‐caren‐4,8‐olide (II), display low antitumor activities against six human tumor cell lines.
ChemInform Abstract: Larrealignans A and B, Novel Lignan Glycosides from the Aerial Parts of Larrea tridentata.
Authors: Yokosuka Akihito , Matsuo Yukiko , Jitsuno Maki , Adachi Kohei , Mimaki Yoshihiro
Published: May 2012

Title compounds (I) are found to show no cytotoxic activity.
ChemInform Abstract: Clickosomes — Using Triazole‐Linked Phospholipid Connectors to Fuse Vesicles.
Authors: Loosli Frederic , Doval David Alonso , Grassi David , Zaffalon Pierre‐Leonard , Favarger France , Zumbuehl Andreas
Published: May 2012

Two complementary artificial diether phospholipids are synthesized and subjected to the Huisgen‐Sharpless click reaction.
ChemInform Abstract: Polyphenols from Sophora yunnanensis, and Their Inhibitory Effects on Nitric Oxide Production.
Authors: Daikonya Akihiro , Kitanaka Susumu
Published: May 2012

Sophorayunnanol (I) is isolated from the roots of Sophora yunnanensis along with eight known polyphenols.
ChemInform Abstract: Constituents of Lagochilus leiacanthus (Labiatae).
Authors: Furukawa Megumi , Suzuki Hideya , Makino Mitsuko , Ogawa Shoujiro , Iida Takashi , Fujimoto Yasuo
Published: May 2012

Two new flavones (Ia), (Ib), their 2′‐O‐β‐D‐glucosides and 15‐demethoxyscupolin (II) are isolated from the whole title herb.
ChemInform Abstract: Morphology Controlled Synthesis of LiV2O5/Ag Nanocomposite Nanotubes with Enhanced Electrochemical Performance.
Authors: Diggikar Rahul S. , Dhavale Vishal M. , Shinde Dhanraj B. , Kanbargi Nihal S. , Kulkarni Milind V. , Kale Bharat B.
Published: May 2012

Uniformly embedded Ag nanoparticles in orthorhombic nanotubes of LiV2O5 are hydrothermally synthesized from aqueous mixtures of LiNO3, AgNO3, NH4VO3, and HNO3 (autoclave, 80 °C, 24 h).
ChemInform Abstract: Dienamine Catalysis: An Emerging Technology in Organic Synthesis
Authors: Ramachary Dhevalapally B. , Reddy Y. Vijayendar
Published: May 2012

Review: 114 refs.
ChemInform Abstract: Vinyl Carbonates, Vinyl Carbamates, and Related Monomers: Synthesis, Polymerization, and Application
Authors: Husar Branislav , Liska Robert
Published: May 2012

Review: 88 refs.
ChemInform Abstract: Mononuclear Cyclophanes
Authors: Shinmyozu T. , Shibahara M.
Published: May 2012

Review: 93 refs.
Structural Variations in Copper(II) Complexes of a Bitopic Bis(pyrazolyl)methane Ligand
Authors: Reger Daniel L. , Pascui Andrea E. , Smith Mark D.
Published: May 2012

The equal molar reaction of Cu(BF4)2·3H2O with the ditopic, bis(pyrazolyl)methane ligand p‐[CH(pz)2]2C6H4 (Lp) where pz is a pyrazolyl ring, in methanol produces [Cu(μ‐Lp)(CH3OH)](BF4)2·(CH3OH)0.62 (1) and a similar reaction in water/methanol yields [Cu(μ‐Lp)(CH3OH)]2(SiF6)(BF4)2·(CH3OH)2 (2). The water/ethanol solvent system yields both [Cu2(μ‐Lp)(H2O)6](SiF6)2·(H2O)4 (3) and [Cu(μ‐Lp)(H2O)](BF4)2·(CH3CH2OH)2 (4), and if the ratio of Cu(BF4)2·3H2O and Lp is changed to 2:1, only 3 forms. Recrystallization of the solid formed from the reaction of THF solutions of Cu(BF4)2·3H2O with Lp from DMSO yields [Cu2(μ‐Lp)(DMSO)6](BF4)4·(DMSO)2·C6H6·(H2O)0.5 (5) and a recrystallization of compound 1 from DMSO yields [Cu2(μ‐Lp)(DMSO)6](BF4)4·(DMSO)2·C6H6 (6). Complexes 1, 2, and 4 are coordination polymers in which the N4O‐coordinated, square‐pyramidal copper(II) ions are oriented in an anti conformation withrespect to the phenylene spacer of Lp. Complexes 3, 5 and 6 are dinuclear with N2O3‐coordinated, square‐pyramidal copper(II) ions again oriented in an anti configuration with respect to the bridging Lp. The square pyramidal geometries show axial elongation, a result of pseudo Jahn–Teller electronic effects. In the cases of the coordination polymers, the axially coordinated solvent molecule is lost at low temperatures upon heating of the crystals. The three compounds in each structural type have nearly the same overall configurations. Cooperative effects of O–H···F, O–H···O and C–H···F hydrogen bonding interactions organize the supramolecular structures and influence the crystal packing of complexes 1–4. The C–H···F interactions have metrics that indicate they are unusually strong, due to the enhanced polarization of the C–H bond and charge assistance from the anionic fluorine atom.
Tissue-based risk assessment of cyclic volatile methyl siloxanes
Authors: Redman Aaron D. , Mihaich Ellen , Woodburn Kent , Paquin Paul , Powell David , McGrath Joy A. , Di Toro Dominic M.
Published: May 2012

Cyclic volatile methyl siloxanes (cVMS) are important consumer materials that are used in personal care products and industrial applications. These compounds have gained increased attention in recent years following the implementation of chemical legislation programs worldwide. Industry-wide research programs are being conducted to characterize the persistence, bioaccumulation, and toxicity (PBT) properties of cVMS materials. As part of this larger effort, a tissue-based risk assessment was performed to further inform the regulatory decision-making process. Measured tissue concentrations of cVMS compounds in fish and benthic invertebrates are compared with critical target lipid body burdens (CTLBBs) as estimated with the target lipid model (TLM) to evaluate risk. Acute and chronic toxicity data for cVMS compounds are compared with data for nonpolar organic chemicals to validate application of the TLM in this effort. The analysis was extended to estimate the contribution from metabolites to the overall cVMS-derived tissue residues using a food chain model calibrated to laboratory and field data. Concentrations of cVMS materials in biota from several trophic levels (e.g., invertebrates, fish) are well below the estimated CTLBBs associated with acute and chronic effects. This analysis, when combined with the limited biomagnification potential for cVMS compounds that was observed in the field, suggests that there is little risk of adverse effects from cVMS materials under present-day emission levels. Environ. Toxicol. Chem. 2012; 31: 1911–1919. © 2012 SETAC
Hybrid grid generation for viscous flow analysis
Authors: Park Seyoun , Jeong Byungduk , Lee Jin Gyu , Shin Hayong
Published: May 2012

Cartesian grid with cut‐cell method has drawn attention of CFD researchers owing to its simplicity. However, it suffers from the accuracy near the boundary of objects especially when applied to viscous flow analysis. Hybrid grid consisting of Cartesian grid in the background, body‐fitted layer near the object, and transition layer connecting the two is an interesting alternative. In this paper, we propose a robust method to generate hybrid grid in two‐dimensional (2D) and three‐dimensional (3D) space for viscous flow analysis. In the first step, body‐fitted layer made of quadrangles (in 2D) or prisms (in 3D) is created near the object's boundary by extruding front nodes with a speed function depending on the minimum normal curvature obtained by quadric surface fitting. To solve global interferences effectively, a level set method is used to find candidates of colliding cells. Then, axis‐aligned Cartesian grid (quadtree in 2D or octree in 3D) is filled in the rest of the domain. Finally, the gap between body‐fitted layer and Cartesian grid is connected by transition layer composed of triangles (in 2D) or tetrahedrons (in 3D). Mesh in transition layer is initially generated by constrained Delaunay triangulation from sampled points based on size function and is further optimized to provide smooth connection. Our approach to automatic hybrid grid generation has been tested with many models including complex geometry and multi‐body cases, showing robust results in reasonable time. Copyright © 2012 John Wiley & Sons, Ltd.
Coupling of finite and hierarchical infinite elements: application to a non‐homogeneous cross‐anisotropic half‐space subjected to a non‐uniform circular loading
Authors: Houmat Abderrahim
Published: May 2012

A method is presented for coupling cubic‐order quadrilateral finite elements with the finite side of a new coordinate ascent hierarchical infinite element. At a common side shared by a hierarchical infinite element and an arbitrary number of finite elements, the displacements are minimized in the least square sense with respect to the degrees‐of‐freedom of the finite elements. This leads to a set of equations that relate the degrees‐of‐freedom of the finite and hierarchical infinite elements on the shared side. The method is applied to a non‐homogeneous cross‐anisotropic half‐space subjected to a non‐uniform circular loading with Young's and shear moduli varying with depth according to the power law. A constant mesh constructed from coupled finite and hierarchical infinite elements is used and convergence is sought simply by increasing the degree of the interpolating polynomial. The displacements and stresses produced by conical and parabolic circular loads applied on the surface are obtained. The efficiency of the proposed method is demonstrated through convergence and comparison studies. New results produced by a frusto‐conical circular load applied on the surface of a half‐space made up of heavily consolidated London clay are provided. The non‐homogeneity parameter and degree of anisotropy are shown to influence the soil response. Copyright © 2012 John Wiley & Sons, Ltd.
Growing Stem Cells: The Impact of Federal Funding Policy on the U.S. Scientific Frontier
Authors: Furman Jeffrey L. , Murray Fiona , Stern Scott
Published: May 2012

This paper articulates a citation‐based approach to science policy evaluation and employs that approach to investigate the impact of the United States’ 2001 policy regarding the federal funding of human embryonic stem cell (hESC) research. We evaluate the impact of the policy on the level of U.S. hESC research, the U.S. position at the knowledge frontier, and the strategic response of U.S. scientists. Consistent with recent research on the science of science and innovation policy, we employ a difference‐in‐differences approach using bibliometric data with the aim of analyzing the causal impact of the policy on cumulative research. Our estimates suggest that in the aftermath of the 2001 policy, U.S. production of hESC research lagged 35 to 40 percent behind anticipated levels. However, this relative decline was largely concentrated in the years 2001 to 2003 and ameliorated over time. The rebound in U.S. hESC research after 2003 was driven by contributions by researchers at elite U.S. institutions and U.S. researchers who collaborated with international partners. The results suggest that scientists respond strategically to research funding restrictions and that modest science policy shifts can have a significant influence on the within‐country composition of research and the pattern of global research collaboration.
Synthesis and application of modified poly (styrene‐alt‐maleic anhydride) networks as a nano chelating resin for uptake of heavy metal ions
Authors: Hasanzadeh Reza , Najafi Moghadam Peyman , Samadi Naser
Published: May 2012

A chelating resin based on modified poly (styrene‐alt‐maleic anhydride) with 3‐aminobenzoic acid was synthesized. This modified resin was further reacted by 1,2‐diaminoethane or 1,3‐diaminopropane in the presence of ultrasonic irradiation to prepare tridimensional chelating resin for the removal of heavy metal ions from aqueous solutions. The adsorption behavior of Fe(II), Cu(II), Zn(II) and Pb(II) ions was investigated by synthesized chelating resins in various pH. Among the synthesized resins, CSMA‐AB1 and CSMA‐AB2 demonstrated a high affinity for the selected metal ions compared to SMA‐AB, and the order of removal percentage changes as follow: Fe(II) > Cu(II) > Zn(II) > Pb(II). The adsorption of all metal ions in acidic medium was moderate, and it was favored at the pH value of 6 and 7. Also, the prepared resins were examined for removal of metal ions from industrial wastewater and were shown to have a very efficient adsorption in the case of Cu(II), Fe(II) and Pb(II); however, the adsorption of Zn(II) was lower than others. The resin was characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, X‐ray diffraction analysis and thermogravimetric analysis/derivative thermogravimetry. Copyright © 2012 John Wiley & Sons, Ltd.
Evolution of metal plating for silicon solar cell metallisation
Authors: Lennon Alison , Yao Yu , Wenham Stuart
Published: May 2012

Increasing silver prices and reducing silicon wafer thicknesses provide incentives for silicon solar cell manufacturing to develop new metallisation strategies that do not rely on screen printing and preferably reduce silver usage. Recently, metal plating has re‐emerged as a metallisation process that may address these future requirements. This paper reports on the evolution of metal plating techniques, from their use in early silicon solar cells, to current light‐induced plating processes. Unlike screen‐printed metallisation, metal plating typically requires an initial patterning step to create openings in a masking layer for the subsequent self‐aligned metallisation. Consequently, relevant recently‐developed dielectric patterning methods are also reviewed because, in many cases, the plating process must be adapted to the properties of the patterning method used. The potential of new light‐induced plating processes to form cost‐effective copper metallisation is supported by the recent activity in the development of metal plating tools for commercial silicon solar cell manufacture. Copyright © 2012 John Wiley & Sons, Ltd.
Functional aliphatic polyesters and nanoparticles prepared by organocatalysis and orthogonal grafting chemistry
Authors: Silvers Angela L. , Chang Chia‐Chih , Emrick Todd
Published: May 2012

We describe the use of organic catalysis for the ring‐opening polymerization of functionalized lactones and conversion of the resulting aliphatic polyesters into crosslinked nanoparticles that carry additional functional groups amenable to further modification. Specifically, highly functional aliphatic polyester homopolymers, as well as random and block copolymers, were prepared by 1,5,7‐triazabicyclo[4.4.0]dec‐5‐ene catalysis, giving polyesters with pendent alkene and alkyne groups. Azide‐alkyne click and thiol‐ene chemistries were used for postpolymerization modification of diblock copolymers possessing alkene groups on one block and alkyne groups on the other block. The polyesters were crosslinked using azide/alkyne cycloaddition, by reaction of α,ω‐diazides with the pendent alkynes on the polyester backbone. This gave polyester nanoparticles possessing alkene functionality, which were subjected to further modification using thiol‐ene reactions to introduce additional functionality. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Copolymers of methyl methacrylate with N‐trifluorophenyl maleimides: High glass transition temperature and low birefringence polymers
Authors: Lou Liping , Tagaya Akihiro , Ide Yoko , Koike Yasuhiro , Okamoto Yoshiyuki
Published: May 2012

Copolymers of methyl methacrylate (MMA) with 2,3,4‐ and 2,4,6‐trifluorophenyl maleimides (TFPMIs) were synthesized by a free radical initiator, azobisisobutyronitrile, in 1,4‐dioxane and also in bulk. The refractive indexes of the copolymers were in the range of 1.49–1.52 at 532 nm. The Tgs were 133–195 °C depending on copolymer compositions. In addition, the copolymers were thermally stable, Td > 350 °C. The orientational and photoelastic birefringence of the copolymers were also investigated. As both of the orientational and photoelastic birefringences of PMMA are negative, whereas those of poly(TFPMI)s are positive, we could obtain nearly zero orientational and photoelastic birefringence polymers when the ratios of 2,3,4‐TFPMI/MMA were 15/85 and 5/95 mol %, respectively. For 2,4,6‐TFPMI, zero orientational and photoelastic birefringences could be obtained when the ratios of 2,4,6‐TFPMI/MMA were 12/88 and 3/97 mol %, respectively. The Tgs of those copolymers with zero birefringences were in the range of 135–140 °C. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Synthesis and polymerizability of CN monomers
Authors: Hall H. K. , Padias Anne Buyle , Kamachi M. , Hashidzume A.
Published: May 2012

The synthesis and polymerizability of imine CN monomers is surveyed. The investigated imines were either far more reactive than similarly substituted CC or CO monomers, or too stable to polymerize. Imines with electron‐attracting substituents on N favor polymerization by anionic mechanism, but led only to low molecular weight polymers. Imines with a donor substituent on N, such as N‐arylmethyleneimines, polymerized by cationic or anionic mechanism. 1‐ and 2‐Aza‐1,3‐butadienes were also rather unstable and polymerized to oligomers. The symmetrically substituted 2,3‐diaza‐1,3‐butadienes could be purified and polymerized successfully using anionic initiators, resulting in both 1,4‐ and 1,2‐structures in the polymer backbone, depending on the substituents. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Hydrogen‐bonded supramolecular polymers containing dimethylsilane groups: Synthesis, crystal structure, and characterization
Authors: Zaltariov Mirela‐Fernanda , Cazacu Maria , Shova Sergiu , Vlad Angelica , Stoica Iuliana , Hamciuc Elena
Published: May 2012

Bis[N‐(4‐carboxyphenyl)phtalimidyl]dimethylsilane prepared by the reaction between bis(3,4‐dicarboxyphenyl)dimethylsilane anhydride and p‐aminobenzoic acid has been used to built three novel hydrogen‐bonded supramolecular polymers as a result of cocrystallization with pyridine derivatives: 4,4′‐bipyridyl (SP1), 1,2‐bis(4‐pyridyl)ethylene (SP2), and 4,4′‐azopyridine (SP3). The structures of the dianhydride, diacid, and derived supramolecular polymers were investigated by Fourier transform infrared (FTIR) and proton magnetic resonance (1H NMR) spectroscopy. Self‐assembling was proved by the presence of the IR absorption bands around 1900 and 2400 cm−1 specific for hydrogen bond. The association constant values were estimated by using FTIR spectroscopy in solid state. According to X‐ray diffraction study, the bis(3,4‐dicarboxyphenyl)dimethylsilane anhydride (1) has an isolated molecular structure. Bis[N‐(4‐carboxyphenyl)phtalimidyl]dimethylsilane (2) molecules are associated in the crystal structure via dimeric OH…O hydrogen bonds resulting in the wavy 1D supramolecular chain. The main packing motif for SP1 and SP3 is represented by wavy chain formed by alternating sequences of 4,4′‐bipyridyl or 4,4′‐azopyridine and bis[N(4‐carboxyphenyl)phtalimidyl]dimethylsilane molecules linked by OH…N hydrogen bonds. Thermal behavior was studied by differential scanning calorimetry and thermogravimetric analysis. The ability for the structuration in film was emphasized by atomic force microscopy. The molecular transport ability of the reversible associations was estimated by dynamic water vapor sorption (DVS) analysis. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Spectroscopic Characterization of Lycopene Extract from Lycopersicum esculentum (Tomato) and Its Evaluation as a Chemopreventive Agent Against Experimental Hepatocarcinogenesis in Mice
Authors: Gupta Prachi , Bansal Mohinder Pal , Koul Ashwani
Published: May 2012

The present study was designed to characterize the lycopene extract (LycT) prepared from tomatoes (Lycopersicum esculentum) and then to evaluate its chemopreventive efficacy in N‐diethylnitrosamine (NDEA)‐induced experimental hepatocarcinogenesis in female Balb/c mice. The extraction of lycopene was carried out using hexane/acetone/ethanol as an extracting medium and then characterized by ultraviolet–visible, nuclear magnetic resonance and Fourier transform infrared spectroscopy. Chemopreventive efficacy of characterized LycT in vivo was evaluated in terms of hepatic tumour incidence, multiplicity, burden, hepatosomatic index and animal survival rate. Results indicated that average lycopene content of the tomato was 11.6–14 mg/kg tomato weight. Spectroscopic data confirmed the structural characteristics of lycopene in the extract. In the animal study, reduction in tumour incidence (42.05%), tumour burden (1.39) and tumour multiplicity (3.42) was observed upon LycT pretreatment to NDEA‐treated animals. Histopathological analysis unravelled that the increased survival rate in LycT + NDEA‐treated animals was due to the delay in the formation of aggressive tumour nodules. These observations indicate that lycopene seems to be an able candidate for chemoprevention in hepatocarcinogenesis resulting from NDEA insults. Copyright © 2012 John Wiley & Sons, Ltd.
Asiaticoside Induces Type I Collagen Synthesis and Osteogenic Differentiation in Human Periodontal Ligament Cells
Authors: Nowwarote Nunthawan , Osathanon Thanaphum , Jitjaturunt Peachaya , Manopattanasoontorn Sukuman , Pavasant Prasit
Published: May 2012

Asiaticoside, an active ingredient extracted from Centella asiatica, has been widely used to promote wound healing. In this study, the effects of asiaticoside on proliferation, protein synthesis, and osteogenic differentiation in human periodontal ligament cells (HPDLs) were investigated. HPDLs were treated with asiaticoside at concentrations of 25, 50, and 100 µg/mL. Cell number was determined by MTT assay. The mRNA expression was analyzed by reverse transcription‐polymerase chain reaction. Western blot analysis and immunocytochemistry were used to confirm protein synthesis. Osteogenic differentiation was determined by alkaline phosphatase activity, osteoblast marker gene expression, and in vitro mineralization. The results showed that asiaticoside treatment, ranging from 25 to 100 mg/mL, had no effect on cytotoxicity or cell proliferation. When HPDLs were treated with asiaticoside in serum‐free medium, dose‐dependent increases in the levels of fibronectin and collagen type I mRNA and protein were observed at 72 h. Moreover, asiaticoside attenuated matrix metalloproteinase‐1 but enhanced tissue inhibitor of metalloproteinase‐1 mRNA expression. The addition of asiaticoside to osteogenic medium resulted in an increase in alkaline phosphatase enzymatic activity, up‐regulation of osteoblast marker gene mRNA expression, and enhancement of mineralization by HPDLs. These results suggest the potential application of asiaticoside for enhancing periodontal tissue healing. Copyright © 2012 John Wiley & Sons, Ltd.
The Effects of an Antiosteoporosis Herbal Formula Containing Epimedii Herba, Ligustri Lucidi Fructus and Psoraleae Fructus on Density and Structure of Rat Long Bones Under Tail‐Suspension, and its Mechanisms of Action
Authors: Siu Wing‐Sum , Wong Hing‐Lok , Lau Ching‐Po , Shum Wai‐Ting , Wong Chun‐Wai , Gao Si , Fung Kwok‐Pui , Lau Clara Bik‐San , Hung Leung‐Kim , Ko Chun‐Hay , Leung Ping‐Chung
Published: May 2012

An innovative anti‐osteoporosis herbal formula containing Epimedii Herba, Ligustri Lucidi Fructus and Psoraleae Fructus (ELP) has been previously shown its bone protecting effects in ovariectomized osteoporotic rats and also in post‐menopausal osteopenic women. This study aimed to investigate the efficacy of ELP against bone loss during physical inactivity or weightlessness. A hindlimb unloading tail‐suspended rat model was used for studying the effects of ELP on bone mineral density (BMD) and bone micro‐architecture. For in vitro mechanistic studies, rat mesenchymal stem cells (MSCs) and mouse macrophage cells (RAW264.7) were used for studying the effects of ELP on osteogenic/adipogenic differentiations and osteoclastogenesis, respectively. Our data illustrated that ELP had a significant preventive effect against bone loss induced by tail‐suspension (TS) at day 28 (p < 0.01) as indicated in the reduction in BMD loss and the preservation of bone micro‐architecture. ELP could significantly promote the osteogenesis and suppress the adipogenesis (p < 0.05) in MSCs. Besides, significant inhibition of osteoclast formation (p < 0.01) was found in ELP‐treated RAW264.7 cells upon receptor activator of nuclear factor kappa‐B ligand induction. Our study presents the first scientific evidence that ELP had a significant preventive effect against bone loss induced by TS through the actions of enhancing osteogenesis, suppressing adipogenesis and osteoclastogenesis. Copyright © 2012 John Wiley & Sons, Ltd.
Baurechtliche und normative Anforderungen an ESG und ESG‐H
Authors: Hof Peter , Ensslen Frank , Reick Martin
Published: May 2012

Die Anforderungen an Einscheiben‐Sicherheitsglas unterscheiden sich je nach Verwendung und danach, ob es heißgelagert werden muss oder nicht. Gleichzeitig stellt sich die Frage, ob die Gläser in Deutschland verwendet werden dürfen oder nur außerhalb Deutschlands. Diese Situation ist für die Produzenten und Anwender nicht immer direkt und leicht zu überblicken. Der folgende Artikel möchte die wesentlichen Grundlagen zu den baurechtlichen und normativen Anforderungen darlegen.
Denkmalgerechte Sanierung einer Stahl‐Glas‐Fassade der Nachkriegsmoderne
Authors: Brenne Winfried , Hoffmann Manfred
Published: May 2012

Die Stahl‐Glas‐Fassade des Interbau‐Objektes Nr. 20 der Architekten Beaudouin und Lopez im Hansa‐Viertel Berlin aus dem Jahr 1957 ist ein typisches Beispiel der Nachkriegsmoderne. Nach 50 Jahren Standzeit wurde eine Sanierung erforderlich. Trotz weitreichender Schädigung bis in die Substanz hinein und thermisch schwieriger Details wie außen geführter Heizleitungen sowie Umbauten und Ergänzungen war der größtmögliche Erhalt der denkmalgeschützten Fassade das Ziel und nicht deren Ersatz durch thermisch getrennte Neubauprodukte.
Transparente Fassaden bei Neubau und Sanierung von Gebäuden
Authors: Maniatis Iris , Siebert Barbara
Published: May 2012

Anforderungen an Gebäude, insbesondere an Fassaden, unterliegen einem Wandel: neben Schutz vor äußeren Einwirkungen sind Energiebilanz und Nachhaltigkeit der Konstruktion wichtig – unter Berücksichtigung ansprechender Gestaltung. Doppelfassaden mit zweiter Haut aus Glas kristallisieren sich als effiziente Lösung heraus. Eine wesentliche Maßnahme zur Reduktion der CO2‐Emissionen ist die Sanierung von Altbauten. Die Renovierung bestehender Gebäude ist meist um vieles komplexer als ein Neubau, da die bestehende Struktur in das neue Konzept zu integrieren ist. Gezeigt wird ein Beispiel der Ertüchtigung eines Hochhauses durch eine Doppelfassade.
Microengineered synthetic cellular microenvironment for stem cells
Authors: Sun Yubing , Weng Shinuo , Fu Jianping
Published: May 2012

Stem cells possess the ability of self‐renewal and differentiation into specific cell types. Therefore, stem cells have great potentials in fundamental biology studies and clinical applications. The most urgent desire for stem cell research is to generate appropriate artificial stem cell culture system, which can mimic the dynamic complexity and precise regulation of the in vivo biochemical and biomechanical signals, to regulate and direct stem cell behaviors. Precise control and regulation of the biochemical and biomechanical stimuli to stem cells have been successfully achieved using emerging micro/nanoengineering techniques. This review provides insights into how these micro/nanoengineering approaches, particularly microcontact printing and elastomeric micropost array, are applied to create dynamic and complex environment for stem cells culture. WIREs Nanomed Nanobiotechnol 2012, 4:414–427. doi: 10.1002/wnan.1175

This article is categorized under:

Nanotechnology Approaches to Biology > Nanoscale Systems in Biology

Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement
Peritoneofascial Suture Method for Facilitating Loop Ileostomy Mobilization
Authors: Jung Sang‐hun , Kim Jae‐hwang
Published: May 2012

Background

Ileostomy closure is a minor procedure and is performed through a small peristomal incision. However, a hard adhesion increases the technical difficulty. A peritoneofascial suture (PFS) will reduce the adhesion layers of the abdominal wall. This study was performed to evaluate whether the PFS method may decrease the extent of adhesions between the bowel and the abdominal wall opening and facilitate ileostomy mobilization.

Methods

Forty‐two patients (24 males and 18 females) with a mean age of 57 years (range = 31–80 years) and who were undergoing ileostomy closure were enrolled. The PFS group and the conventional group had 18 and 24 patients, respectively. The intraoperative findings such as degree of adhesion, mobilization time, and associated bowel injury were analyzed.

Results

The thickness of the abdominal wall and the rectus abdominis was similar in both groups. The overall operation time was shorter in the PFS group than in the conventional group (50.9 vs. 80.4 min, respectively, p = 0.001). The ileostomy mobilization time was also shorter in the PFS group than in the conventional group (18.9 vs. 44.7 min, respectively, p < 0.001). The procedure was technically easier in the PFS group more frequently than in the conventional group (77.8 % vs. 31.6 %, respectively, p = 0.013). Bowel injury during mobilization was more common in the conventional group than in the PFS group (50.0 % vs. 16.7 %, respectively, p = 0.053).

Conclusions

The peritoneofascial suture method is a simple procedure, and it may facilitate ileostomy mobilization by decreasing adhesion layers. To confirm the technical advantage of this method a randomized study will be needed.