bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protein recovery from surfactant precipitation
Authors: Cheng Shu Ian , Stuckey David C. 
Published: September 2011

AbstractThe recovery of lysozyme from an aqueous solution containing precipitated lysozyme‐AOT complexes formed by the direct addition of sodium bis‐(2‐ethylhexyl) sulfosuccinate (AOT) to a lysozyme solution was studied using both solvents, and a counterionic surfactant. Ethanol, methanol and solvent mixtures dissolved the surfactant precipitate and recovered lysozyme as a solid. Recovery efficiency and protein stability varied with the type of solvent used. An entirely different method of recovery was also evaluated using a counterionic surfactant: trioctylmethylammonium chloride (TOMAC) which bound to AOT releasing lysozyme into solution. Complete recovery (100%) of lysozyme was achieved at a molar ratio of 2:1 (TOMAC:AOT), and the original protein activity was maintained in the final aqueous phase. The recovered lysozyme retained its secondary structure as observed in circular dichroism (CD) spectra. Specific activity studies show that counterionic surfactant extraction does not alter the biological activity of the enzyme. © 2011 American Institute of Chemical Engineers Biotechnol. Prog.,, 2011
Effect of needle geometry on flow rate and cell damage in the dispensing‐based biofabrication process
Authors: Li Minggan , Tian Xiaoyu , Schreyer David J. , Chen Xiongbiao 
Published: September 2011

AbstractBiodispensing techniques have been widely applied in biofabrication processes to deliver cell suspensions and biomaterials to create cell‐seeded constructs. Under identical operating conditions, two types of dispensing needles—tapered and cylindrical—can result in different flow rates of material and different cell damage percent induced by the mechanical forces. In this work, mathematical models of both flow rate and cell damage percent in biodispensing systems using tapered and cylindrical needles, respectively, were developed, and experiments were carried out to verify the effectiveness of the developed models. Both simulations and experiments show tapered needles produce much higher flow rates under the same pressure conditions than cylindrical needles. Use of a lower pressure in a tapered needle can therefore achieve the same flow rate as that in a cylindrical needle. At equivalent flow rates, cell damage in a tapered needle is lower than that in a cylindrical one. Both Schwann cells and 3T3 fibroblasts, which have been widely used in tissue engineering, were used to validate the cell damage models. Application of the developed models to specify the influence of process parameters, including needle geometry and air pressure, on the flow rate and cell damage percent represents a significant advance for biofabrication processes. The models can be used to optimize process parameters to preserve cell viability and achieve the desired cell distribution in dispensing‐based biofabrication. © 2011 American Institute of Chemical Engineers Biotechnol. Prog.,, 2011
And then there were four: Anatomical observations on the pollical palmar interosseous muscle in humans
Authors: Morrison Peter E. , Hill Robert V. 
Published: September 2011

AbstractAlthough anatomists generally agree upon the presence of four interosseous muscles in the human hand, the number and identity of the palmar interosseous muscles remains contentious. Recent studies suggest that a majority of human hands possess four palmar interossei, yet most contemporary texts suggest the presence of only three. The pollical palmar interosseous muscle (PPIM), associated with the first digit, has been alternatively interpreted as a distinct muscle, part of another hand muscle, or nonexistent. We examined 45 hands from 23 human cadavers to investigate the prevalence of this muscle and found it to occur in varying degrees of expression in 91% of specimens. We also tested the hypothesis that the PPIM forms the smaller part of a “parallel muscle combination” and is therefore ideally suited to act as a proprioceptive organ. Results do not show a significantly higher density of muscle spindles in the PPIM relative to the adjacent adductor pollicis, provisionally refuting this hypothesis. The presence of the PPIM, observed in the majority of hands from several populations, indicates that it should be regularly included in mainstream anatomy texts and atlases. Clin. Anat. 24:978–983, 2011. © 2011 Wiley Periodicals, Inc.
Connection between the spinal dura mater and suboccipital musculature: Evidence for the myodural bridge and a route for its dissection—A review
Authors: Kahkeshani Kourosh , Ward Peter J. 
Published: September 2011

AbstractA connective tissue link between the spinal dura mater and the rectus capitis posterior minor muscle was first described in 1995 and has since been readily demonstrated via dissection, magnetic resonance imaging, and plastinated cross‐sections of the upper cervical region (Hack et al. [1995] Spine 20:2484–2486). This structure, the so‐called “myodural bridge,” has yet to be included in any of the American anatomy textbooks or dissection guides commonly used in medical education. This direct anatomic link between the musculoskeletal system and the dura mater has important ramifications for the treatment of chronic cervicogenic headache. This article summarizes the anatomic and clinical research literature related to this structure and provides a simple approach to dissect the myodural bridge and its attachment to the posterior atlanto‐occipital membrane/spinal dura mater complex and summarizes the case for its possible inclusion in medical anatomy curricula. Clin. Anat. 25:415–422, 2012. © 2011 Wiley Periodicals, Inc.
DLP: A tool to develop technical and soft skills in engineering
Authors: Redoli Judith , Mompó Rafael , de la Mata David , Doctor Miguel 
Published: September 2011

AbstractThis article describes how to develop and implement a tool that enables engineering students to acquire soft‐skills taking advantage of the purely technical engineering educational tasks. Delphi Learning Package (DLP) tool is based on a Delphi strategic consulting method. Generally, this method is used to obtain long‐term forecasts from knowledge of groups of experts. Some adjustments have been made to Delphi method in order to apply it to learning and acquiring soft‐skills in engineering. For instance, this tool can be used to guide students toward obtaining key parameters for a technical matter or to find the best solutions to an intricate multiple‐solution problem. Thus, students will have to use not only knowledge learned on the subject of engineering, but also knowledge resulting from handling‐related documentation. By tackling a multiple‐solution problem, students develop different soft skills such as critical thinking, synthesis ability, inference, and argumentation. In order to judge the value of this tool, two pilot projects have been developed involving fourth year students with a major in Telecommunications Engineering. This tool can be used freely by contacting the authors of this article. © 2011 Wiley Periodicals, Inc. Comput Appl Eng Educ 21:E51–E61, 2013
Definition of the Common and Divergent Steps in Carbapenem β‐Lactam Antibiotic Biosynthesis
Authors: Bodner Micah J. , Li Rongfeng , Phelan Ryan M. , Freeman Michael F. , Moshos Kristos A. , Lloyd Evan P. , Townsend Craig A. 
Published: September 2011

AbstractApproximately 50 naturally occurring carbapenem β‐lactam antibiotics are known. All but one of these have been isolated from Streptomyces species and are disubstituted structural variants of a simple core that is synthesized by Pectobacterium carotovorum (Erwinia carotovora), a phylogenetically distant plant pathogen. While the biosynthesis of the simple carbapenem, (5R)‐carbapen‐2‐em‐3‐carboxylic acid, is impressively efficient requiring only three enzymes, CarA, CarB and CarC, the formation of thienamycin, one of the former group of metabolites from Streptomyces, is markedly more complex. Despite their phylogenetic separation, bioinformatic analysis of the encoding gene clusters suggests that the two pathways could be related. Here we demonstrate with gene swapping, stereochemical and kinetics experiments that CarB and CarA and their S. cattleya orthologues, ThnE and ThnM, respectively, are functionally and stereochemically equivalent, although their catalytic efficiencies differ. The biosynthetic pathways, therefore, to thienamycin, and likely to the other disubstituted carbapenems, and to the simplest carbapenem, (5R)‐carbapen‐2‐em‐3‐carboxylic acid, are initiated in the same manner, but share only two common steps before diverging.
Percutaneous stent implantation into coronary arteries in infants
Authors: Bratincsák András , Salkini Anas , El‐Said Howaida G. , Moore John W. 
Published: September 2011

AbstractObjectives: To investigate the feasibility, procedural techniques, safety, and overall potential of percutaneous coronary angioplasty and stent implantation in infants with coronary artery disease and acute coronary syndrome. Background: Despite extensive experience in adult patients, percutaneous coronary intervention remains uncommon in children and extremely rare in infants. Methods: Retrospective review including all children who underwent percutaneous coronary angioplasty in Rady Children's Hospital—San Diego during a period of 4 years. Results: Seven children including four children less than 15 months of age underwent percutaneous coronary intervention with coronary stent implantation in the proximal portion of the left or right coronary arteries. Successful stent placement with excellent revascularization was achieved in all cases. Mean coronary artery diameter was 0.65 mm prior to stent placement. Balloon angioplasty resulted in suboptimal resolution of coronary stenosis, thus bare metal stents were implanted in all cases, dilated to a mean of 2.5‐mm internal diameter. Average intervention‐free period was 434 days after stent implantation. In‐stent re‐stenosis and stent thrombosis did not occur if the implanted stent diameter was greater than 2.5 mm and the patient received dual anti‐platelet therapy. Conclusions: Our experience suggests that coronary artery stent implantation is a feasible and relatively safe palliative option in infants and toddlers with coronary stenosis. It is a viable strategy for bridging patients with acute ischemia or poor ventricular function to elective surgical revascularization or transplantation. © 2011 Wiley Periodicals, Inc.
Tuning of Active Sites in NiNbO Catalysts for the Direct Conversion of Ethane to Acetonitrile or Ethylene
Authors: Rubio‐Marcos Fernando , Rojas Elizabeth , López‐Medina Ricardo , Guerrero‐Pérez M. Olga , Bañares Miguel A. , Fernandez José F. 
Published: September 2011

AbstractNiO nanoparticles that are highly active for the ethane activation have been prepared. These nanoparticles have been dispersed on the surface of two different Nb2O5 materials by using a novel dry nanodispersion method. This article describes the characterization and catalytic behavior of both series of catalysts as well as the nature of the active sites required for the transformation of ethane into acetonitrile and/or ethylene. It is demonstrated how such active sites present in the catalysts are obtained through this novel dry mixing method. The catalysts obtained are promising catalytic materials for both, ethane ammoxidation and oxidative dehydration (ODH) reactions.
Systematic Synthesis of Inhibitors of the Two First Enzymes of the Bacterial Heptose Biosynthetic Pathway: Towards Antivirulence Molecules Targeting Lipopolysaccharide Biosynthesis
Authors: Durka Maxime , Tikad Abdellatif , Périon Régis , Bosco Michael , Andaloussi Mounir , Floquet Stéphanie , Malacain Elodie , Moreau François , Oxoby Mayalen , Gerusz Vincent , Vincent Stéphane P. 
Published: September 2011

AbstractL‐Heptoses (L‐glycero‐D‐manno‐heptopyranoses) are constituents of the inner core of lipolysaccharide (LPS), a molecule playing key roles in the mortality of many infectious diseases as well as in the virulence of many human pathogens. The inhibition of the first enzymes of the bacterial heptose biosynthetic pathway is an almost unexplored field to date although it appears to be a very novel way for the development of antivirulence drugs. We report the synthesis of a series of D‐glycero‐D‐manno‐heptopyranose 7‐phosphate (H7P) analogues and their inhibition properties against the isomerase GmhA and the the kinase HldE, the two first enzymes of the bacterial heptose biosynthetic pathway. The heptose structures have been modified at the 1‐, 2‐, 6‐ and 7‐positions to probe the importance of the key structural features of H7P that allow a tight binding to the target enzymes; H7P being the product of GmhA and the substrate of HldE, the second objective was to find structures that could simultaneously inhibit both enzymes. We found that GmhA and HldE were extremely sensitive to structural modifications at the 6‐ and 7‐ positions of the heptose scaffold. To our surprise, the epimeric analogue of H7P displaying a D‐glucopyranose configuration was found to be the best inhibitor of both enzymes but also the only molecule of this series that could inhibit GmhA (IC50=34 μM) and HldE (IC50=9.4 μM) in the low micromolar range. Noteworthy, this study describes the first inhibitors of GmhA ever reported, and paves the way to the design of a second generation of molecules targeting the bacterial virulence.
A Unique Case of Oxidative Addition of Interhalogens IX (X=Cl, Br) to Organodiselone Ligands: Nature of the Chemical Bonding in Asymmetric ISeX Polarised Hypervalent Systems
Authors: Juárez‐Pérez Emilio José , Aragoni M. Carla , Arca Massimiliano , Blake Alexander J. , Devillanova Francesco A. , Garau Alessandra , Isaia Francesco , Lippolis Vito , Núñez Rosario , Pintus Anna , Wilson Claire 
Published: September 2011

AbstractThe reactivity of the imidazoline‐2‐selone derivatives 1,1′‐methylenebis(3‐methyl‐4‐imidazoline‐2‐selone) (D1) and 1,2‐ethylenebis(3‐methyl‐4‐imidazoline‐2‐selone) (D2) towards the interhalogens IBr and ICl has been investigated in the solid state with the aim of synthesising “T‐shaped” hypervalent chalcogen compounds featuring the extremely rare linear asymmetric IEX moieties (E=S, Se; X=Br, Cl). X‐ray diffraction analysis and FT‐Raman measurements provided a clear indication of the presence in the compounds obtained of discrete molecular adducts containing ISeBr and ISeCl hypervalent moieties following a unique oxidative addition of interhalogens IX (X=Cl, Br) to the organoselone ligands. In all asymmetric hypervalent systems isolated, a strong polarisation was observed, with longer bond lengths at the selenium atom involving the most electronegative halogen. A topological electron density analysis on model compounds based on the quantum theory of atoms‐in‐molecules (QTAIM) and electron localisation function (ELF) established the three‐centre–four‐electron (3c–4e) nature of the bonding in these very polarised selenium hypervalent systems and new criteria were suggested to define and ascertain the hypervalency of the selenium atoms in these and related halogen and interhalogen adducts.
Dopant Segregation Analysis on Sb:SnO2 Nanocrystals
Authors: Stroppa Daniel G. , Montoro Luciano A. , Beltrán Armando , Conti Tiago G. , da Silva Rafael O. , Andrés Juan , Leite Edson R. , Ramirez Antonio J. 
Published: September 2011

AbstractThe development of reliable nanostructured devices is intrinsically dependent on the description and manipulation of materials’ properties at the atomic scale. Consequently, several technological advances are dependent on improvements in the characterization techniques and in the models used to describe the properties of nanosized materials as a function of the synthesis parameters. The evaluation of doping element distributions in nanocrystals is directly linked to fundamental aspects that define the properties of the material, such as surface‐energy distribution, nanoparticle shape, and crystal growth mechanism. However, this is still one of the most challenging tasks in the characterization of materials because of the required spatial resolution and other various restrictions from quantitative characterization techniques, such as sample degradation and signal‐to‐noise ratio. This paper addresses the dopant segregation characterization for two antimony‐doped tin oxide (Sb:SnO2) systems, with different Sb doping levels, by the combined use of experimental and simulated high‐resolution transmission electron microscopy (HRTEM) images and surface‐energy ab initio calculations. The applied methodology provided three‐dimensional models with geometrical and compositional information that were demonstrated to be self‐consistent and correspond to the systems’ mean properties. The results evidence that the dopant distribution configuration is dependent on the system composition and that dopant atom redistribution may be an active mechanism for the overall surface‐energy minimization.
Dehydrogenation of Dodecahydro‐N‐ethylcarbazole on Pd/Al2O3 Model Catalysts
Authors: Sobota Marek , Nikiforidis Ioannis , Amende Max , Zanón Beatriz Sanmartín , Staudt Thorsten , Höfert Oliver , Lykhach Yaroslava , Papp Christian , Hieringer Wolfgang , Laurin Mathias , Assenbaum Daniel , Wasserscheid Peter , Steinrück Hans‐Peter , Görling Andreas , Libuda Jörg 
Published: September 2011

AbstractTo elucidate the dehydrogenation mechanism of dodecahydro‐N‐ethylcarbazole (H12‐NEC) on supported Pd catalysts, we have performed a model study under ultra high vacuum (UHV) conditions. H12‐NEC and its final dehydrogenation product, N‐ethylcarbazole (NEC), were deposited by physical vapor deposition (PVD) at temperatures between 120 K and 520 K onto a supported model catalyst, which consisted of Pd nanoparticles grown on a well‐ordered alumina film on NiAl(110). Adsorption and thermally induced surface reactions were followed by infrared reflection absorption spectroscopy (IRAS) and high‐resolution X‐ray photoelectron spectroscopy (HR‐XPS) in combination with density functional theory (DFT) calculations. It was shown that, at 120 K, H12‐NEC adsorbs molecularly both on the Al2O3/NiAl(110) support and on the Pd particles. Initial activation of the molecule occurs through CH bond scission at the 8a‐ and 9a‐positions of the carbazole skeleton at temperatures above 170 K. Dehydrogenation successively proceeds with increasing temperature. Around 350 K, breakage of one CN bond occurs accompanied by further dehydrogenation of the carbon skeleton. The decomposition intermediates reside on the surface up to 500 K. At higher temperatures, further decay to small fragments and atomic species is observed. These species block most of the absorption sites on the Pd particles, but can be oxidatively removed by heating in oxygen at 600 K, fully restoring the original adsorption properties of the model catalyst.
From a Stable Silanone Complex to Isolable, Donor‐Supported Silicoxonium Halides [LSi(dmap)OSiMe3]+X−
Authors: Xiong Yun , Yao Shenglai , Irran Elisabeth , Driess Matthias 
Published: September 2011

AbstractThe first donor‐stabilized silylated silicoxonium species [LSiOSiMe3]+ (L=(RN)C(CH2)CHCMe(NR), R=2,6‐iPr2C6H3) have been synthesized from the reaction of the dmap‐supported (dmap=p‐dimethylaminopyridine) silanone complex [LSi(dmap)O] (1) with trimethylsilyl halides. Although the reaction with Me3SiCl leads directly to the SiO addition product [LSi(Cl)OSiMe3] (2), the ionic silicoxonium bromide [L(dmap)SiOSiMe3]+Br− (3) can be obtained as a primary product of the reaction with Me3SiBr, which affords [LSi(Br)OSiMe3] (4) with release of the dmap ligand at room temperature in THF. In the case of Me3SiI, the reaction furnishes the silicoxonium iodide [L(dmap)SiOSiMe3]+I− (5) as the most stable species. Compounds 2–5 were isolated and fully characterized through multinuclear NMR spectroscopy, mass spectrometry, elemental analyses, and single‐crystal X‐ray diffraction analyses.
Catalyzed Selective Direct α‐ and γ‐Alkylation of Aldehydes with Cyclic Benzyl Ethers by Using T+BF4− in the Presence of an Inexpensive Organic Acid or Anhydride
Authors: Richter Heinrich , Rohlmann Renate , García Mancheño Olga 
Published: September 2011

AbstractThe cross dehydrogenative coupling (CDC) of cyclic benzyl ethers with aliphatic and α,β‐unsaturated aldehydes has been developed. The mild reaction conditions, in which an N‐oxoammonium salt derived from TEMPO (2,2,6,6‐tetramethyl‐1‐piperidinoxyl) is employed as the oxidant in combination with a Cu catalyst, allow the use of relatively redox‐unstable aldehydes under oxidative CDC conditions. The addition of a catalytic amount of trifluoroacetic acid (TFA) or Ac2O facilitates the reaction and increases the efficiency and selectivity. In contrast to the expected α‐alkylation obtained with aliphatic aldehydes, α,β‐unsaturated aldehydes led preferentially to the more challenging γ‐alkylated products. The utility of the developed methodology was demonstrated by the synthesis of isochromane‐derived bioactive compounds, such as the dopamine antagonist sonepiprazole.
Heteroscorpionate Rare‐Earth Metal Zwitterionic Complexes: Syntheses, Characterization, and Heteroselective Catalysis on the Ring‐Opening Polymerization of rac‐Lactide
Authors: Zhang Zhichao , Cui Dongmei 
Published: September 2011

AbstractNovel neutral phosphine‐modified heteroscorpionate ligand (3,5‐Me2Pz)2CHPPh2 (1) and its derivatives oxophosphine (2) and iminophosphine (3) heteroscorpionates were synthesized for the first time. These neutral heteroscorpionate ligands displayed unique chemistry towards rare‐earth metal tris(alkyl)s [Ln(CH2SiMe3)3(thf)2] (Ln=Y, Lu, Sc). The reaction between compound 1 and [Ln(CH2SiMe3)3(thf)2] afforded heteroscorpionate rare‐earth metal trialkyl adduct complexes 4 a–c. Compounds 2 and 3 were treated with [Ln(CH2SiMe3)3(thf)2] to give the unprecedented zwitterionic heteroscorpionate rare‐earth metal dialkyls 5 and 6, respectively. In the process, the heteroscorpionates transferred to the carbanions by means of methine CH bond cleavage that was attributed to the presence of the electron‐withdrawing groups. In addition the ligand and central metal showed a concerted effect on both the catalytic activity and specific selectivity of complexes 4–6 for the ring‐opening polymerization (ROP) of rac‐lactide (rac‐LA). All the adduct complexes 4 were nonselective and gave atactic polylactide (PLA), probably due to the dissociation of ligand 1 from the active metal center during the polymerization. Strikingly, zwitterionic complexes 5 catalyzed rapid ROP of rac‐LA to produce PLAs with heterotacticity up to 0.87. However, the zwitterionic complexes 6 were less active and less selective than 5, which might be on account of the stronger coordination of the tetradentate ligand. Complexes 5 represent rare examples of the selective ROP of rac‐LA mediated by rare‐earth metal complexes supported by non‐bisphenolate ligands.
A Green and Highly Efficient Protocol for Catalyst‐free Knoevenagel Condensation and Michael Addition of Aromatic Aldehydes with 1,3‐Cyclic Diketones in PEG‐400
Authors: Firouzeh Nemati , Hossein Kiani 
Published: September 2011

AbstractA convenient, highly efficient and green approach for synthesis of tetraketones from aromatic aldehydes with dimedone and 1,3‐indanedione at room temperature in PEG‐400 is described. The use of PEG‐400 as the reaction medium and avoiding the use of any catalyst makes the process environmentally benign. Seven new compounds are reported.