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Synthetic
Terms modified by Synthetic Selected AbstractsGossip-based search selection in hybrid peer-to-peer networksCONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 2 2008M. Zaharia Abstract We present GAB, a search algorithm for hybrid peer-to-peer networks, that is, networks that search using both flooding and a distributed hash table (DHT). GAB uses a gossip-style algorithm to collect global statistics about document popularity to allow each peer to make intelligent decisions about which search style to use for a given query. Moreover, GAB automatically adapts to changes in the operating environment. Synthetic and trace-driven simulations show that compared to a simple hybrid approach that always floods first, trying a DHT if too few results are found, GAB reduces the response time by 25,50% and the average query bandwidth cost by 45%, with no loss in recall. GAB scales well, with only a 7% degradation in performance despite a tripling in system size. Copyright © 2007 John Wiley & Sons, Ltd. [source] Minerals as Model Compounds for Cu/ZnO Catalyst Precursors: Structural and Thermal Properties and IR Spectra of Mineral and Synthetic (Zincian) Malachite, Rosasite and Aurichalcite and a Catalyst Precursor MixtureEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 10 2009Malte Behrens Abstract The Cu/ZnO system is a model for Cu/ZnO/Al2O3 catalysts, which are employed industrially for the synthesis of methanol. These catalysts are usually prepared from mixed basic carbonate precursors. A complex phase mixture, with constituents structurally related to the minerals rosasite andaurichalcite, is present at the industrially applied composition (Cu/Zn , 70:30). Using minerals and phase-pure synthetic samples as references, a comprehensive characterisation of such a phase mixture, including the determination of the individual compositions of the different phases, has been attempted by complementary analytical laboratory techniques (XRD, TGA, IR). The results are critically discussed in light of the complexity of the system. A thermally very stable carbonate species , well-known for mixed synthetic systems , is also detected for the mineral reference samples. Significant amounts of amorphous phases are found to be present in the synthetic zincian malachite sample but not in synthetic aurichalcite or the catalyst precursor. A simplified explanation for the shift of the characteristic 20 reflection of the malachite structure as a function of Zn incorporation based on the varying average Jahn,Teller distortion of the MO6 octahedra is proposed. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Synthetic, Structural, and Electrochemical Studies of 2-Ferrocenyl- and2-Cymantrenyl-Functionalized 2,3-Dihydro-1H -1,3,2-diazaboroles and1,3,2-DiazaborolidenesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 23 2005Lothar Weber Abstract Reaction of (dibromoboryl)ferrocene (1) with 1 equiv. of the diazabutadiene tBuN=CH,CH=NtBu, and subsequent reduction of the obtained borolium salt 2 with sodium amalgam, affords the first ferrocenyl-functionalized 1,3,2-diazaborole (3). Similarly, 1,1,-bis(dibromoboryl)ferrocene (4) can be transformed into compound 6, which contains two diazaborolyl substituents at the ferrocene core. Treatment of precursors 1 and 4 with 1,2-bis(tert -butylamino)ethane in the presence of Et3N gives rise to the formation of the diazaborolidine derivatives 13 and 14. 1-Dibromoboryl-3-methylcymantrene (7) was also treated with tBuN=CH,CH=NtBu to give the borolium salt 8, which was subsequently reduced to the 2-cymantrenyl-diazaborole 9. Treatment of 7 with tBuN(H)CH2CH2N(H)tBu in the presence of Et3N furnished the corresponding 2-cymantrenyl-diazaborolidine 15. The novel compounds were characterized by elemental analyses and various spectroscopic techniques (IR; 1H, 13C, and 11B NMR; MS). The molecular structures of 3, 6, and 15 were elucidated by X-ray diffraction analyses. Cyclovoltammetric studies of the ferrocene derivatives at high scan rates show features of a quasireversible oxidation at the iron center. The heterocyclic groups serve as electron donors, considerably lowering the oxidation potential of the central iron atoms when compared to the parent compound ferrocene. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005) [source] Synthetic and Mechanistic Aspects of Acid-Catalyzed Disproportionation of Dialkyl Diarylmethyl Ethers: A Combined Experimental and Theoretical StudyEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 25 2009Margherita Barbero Abstract The disproportionation reactions of various dialkyl diarylmethyl ethers have been carried out in the presence of a catalytic amount (10 mol-%) of o -benzenedisulfonimide as a Brønsted acid catalyst; the reaction conditions were mild, and the yields of the diarylmethane target products were good. The catalyst was easily recovered and purified, ready to be used in further reactions. The theoretical study confirmed that the reaction proceeds in two steps: The formation of a carbocation from the protonated ether followed by hydride transfer. Although the hydride transfer is the rate-determining step, it is the stability of the carbocation that determines the reaction rate and therefore the yields. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) [source] Stereostructural Determination by a Synthetic and NMR-Based Approach of Three Oxazinins Isolated from Adriatic MusselsEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 32 2007Patrizia Ciminiello Abstract Two oxazinins, namely oxazinin-5 and -6, along with a related linear precursor (preoxazinin-7) were isolated from toxic mussels collected along the Northern Adriatic coasts in October 2005. Determination of the planar structure of these novel compounds was achieved through extensive NMR spectroscopic analysis, whereas a synthetic approach was crucial for their absolute stereochemical elucidation.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Seismic data reconstruction using multidimensional prediction filtersGEOPHYSICAL PROSPECTING, Issue 2 2010M. Naghizadeh ABSTRACT In this paper we discuss a beyond-alias multidimensional implementation of the multi-step autoregressive reconstruction algorithm for data with missing spatial samples. The multi-step autoregressive method is summarized as follows: vital low-frequency information is first regularized adopting a Fourier based method (minimum weighted norm interpolation); the reconstructed data are then used to estimate prediction filters that are used to interpolate higher frequencies. This article discusses the implementation of the multi-step autoregressive method to data with more than one spatial dimension. Synthetic and real data examples are used to examine the performance of the proposed method. Field data are used to illustrate the applicability of multidimensional multi-step autoregressive operators for regularization of seismic data. [source] Minimum weighted norm wavefield reconstruction for AVA imagingGEOPHYSICAL PROSPECTING, Issue 6 2005Mauricio D. Sacchi ABSTRACT Seismic wavefield reconstruction is posed as an inversion problem where, from inadequate and incomplete data, we attempt to recover the data we would have acquired with a denser distribution of sources and receivers. A minimum weighted norm interpolation method is proposed to interpolate prestack volumes before wave-equation amplitude versus angle imaging. Synthetic and real data were used to investigate the effectiveness of our wavefield reconstruction scheme when preconditioning seismic data for wave-equation amplitude versus angle imaging. [source] Iterative resolution estimation in least-squares Kirchhoff migrationGEOPHYSICAL PROSPECTING, Issue 6 2002Sergey Fomel ABSTRACT We apply iterative resolution estimation to least-squares Kirchhoff migration. Reviewing the theory of iterative optimization uncovers the common origin of different optimization methods. This allows us to reformulate the pseudo-inverse, model resolution and data resolution operators in terms of effective iterative estimates. When applied to Kirchhoff migration, plots of the diagonal of the model resolution matrix reveal low illumination areas on seismic images and provide information about image uncertainties. Synthetic and real data examples illustrate the proposed technique and confirm the theoretical expectations. [source] Time-varying time-shift correction by quasi-elastic deformation of seismic tracesGEOPHYSICAL PROSPECTING, Issue 2 2000Masjukov Residual static correction is based on a model of time shifts (delays) that depend solely on source and receiver locations at the surface. This assumption is valid if all raypaths are vertical in the near-surface layering. We consider a more general model of the time-varying time shifts that remain after hyperbolic NMO correction (of non-hyperbolic trajectories) and static correction. We assume that the wavelet distortion caused by the time-varying shifts is smooth. We have developed an algorithm for its correction (phase correction), based on minimization of the target functional with a penalty term similar to the quasi-elastic energy of the time-axis deformation. The use of a mechanical analogy for optimization is well known (e.g. simulated annealing). We propose here a stable numerical method that deals with a pair of seismic traces. It may be applied to phase correction of CMP (or CDP) gathers and stacked sections. Synthetic and field examples confirm that our method appreciably increases the signal-to-noise ratio, and improves the coherence and resolution. [source] Synthetic and mechanistic aspects of preparation of phosphinito- and phosphito-mercuries,HETEROATOM CHEMISTRY, Issue 3 2008Jacek E. Nycz A >PO, (1) type of anion has been used as an efficient synthetic precursor of four-coordinated compounds: R2P(O)Hg(O)PR2 (5) and R2P(O)HgBz (3) (R = alkoxy, alkyl, aryl). They were obtained in good yield. Bis(t -butyl-phenylphosphinito-P)mercury (meso and rac) (5c,d) selectively decomposed into 1,2-di- t -butyl-1,2-diphenyldiphosphane 1,2-dioxide (meso and rac) (6c,d). Furthermore, some mechanistic aspects of the synthesis of mentioned compounds are elaborated.© 2008 Wiley Periodicals, Inc. Heteroatom Chem 19:234,237, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20409 [source] Tissue Engineering Strategies Designed to Realize the Endogenous Regenerative Potential of Peripheral NervesADVANCED MATERIALS, Issue 46 2009Vivek Mukhatyar Abstract http://doi.wiley.com/10.1002/adma.v21:32/33 Bridging peripheral nerve gaps without the use of autografts has significant clinical importance. But in order to rationally design novel scaffolds, a good understanding of the nerve regeneration process is vital. Appropriate amount of structural and chemical cues are required to stimulate the endogenous mechanisms of repair and functional recovery. Synthetic and natural materials present various opportunities to induce the growth of supporting cells as well as promote axon regeneration. An overview of tissue engineering strategies currently being explored that stimulate the different steps of the regenerative sequence is presented. [source] Preparation of Arylphosphonates by Palladium(0)-Catalyzed Cross-Coupling in the Presence of Acetate Additives: Synthetic and Mechanistic StudiesADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 18 2009Marcin Kalek Abstract An efficient protocol for the synthesis of arylphosphonate diesters via a palladium-catalyzed cross-coupling of H-phosphonate diesters with aryl electrophiles, promoted by acetate ions, was developed. A significant shortening of the cross-coupling time in the presence of the added acetate ions was achieved for bidentate and monodentate supporting ligands, and for different aryl electrophiles (iodo, bromo and triflate derivatives). The reaction conditions were optimized in terms of amount of the catalyst, supporting ligands, and source of the acetate ion used. Various arylphosphonates, including those of potential biological significance, were synthesized using this newly developed protocol. Some mechanistic aspects of the investigated reactions are also discussed. [source] Highly Ordered Interstitial Water Observed in Bone by Nuclear Magnetic Resonance,JOURNAL OF BONE AND MINERAL RESEARCH, Issue 4 2005Erin E Wilson Abstract NMR was used to study the nanostructure of bone tissue. Distance measurements show that the first water layer at the surface of the mineral in cortical bone is structured. This water may serve to couple the mineral to the organic matrix and may play a role in deformation. Introduction: The unique mechanical characteristics of bone tissue have not yet been satisfactorily connected to the exact molecular architecture of this complex composite material. Recently developed solid-state nuclear magnetic resonance (NMR) techniques are applied here to the mineral component to provide new structural distance constraints at the subnanometer scale. Materials and Methods: NMR dipolar couplings between structural protons (OH, and H2O) and phosphorus (PO4) or carbon (CO3) were measured using the 2D Lee-Goldburg Cross-Polarization under Magic-Angle Spinning (2D LG-CPMAS) pulse sequence, which simultaneously suppresses the much stronger proton-proton dipolar interactions. The NMR dipolar couplings measured provide accurate distances between atoms, e.g., OH and PO4 in apatites. Excised and powdered femoral cortical bone was used for these experiments. Synthetic carbonate (,2-4 wt%)-substituted hydroxyapatite was also studied for structural comparison. Results: In synthetic apatite, the hydroxide ions are strongly hydrogen bonded to adjacent carbonate or phosphate ions, with hydrogen bond (O-H) distances of ,1.96 Å observed. The bone tissue sample, in contrast, shows little evidence of ordered hydroxide. Instead, a very ordered (structural) layer of water molecules is identified, which hydrates the small bioapatite crystallites through very close arrangements. Water protons are ,2.3-2.55 Å from surface phosphorus atoms. Conclusions: In synthetic carbonated apatite, strong hydrogen bonds were observed between the hydroxide ions and structural phosphate and carbonate units in the apatite crystal lattice. These hydrogen bonding interactions may contribute to the long-range stability of this mineral structure. The biological apatite in cortical bone tissue shows evidence of hydrogen bonding with an ordered surface water layer at the faces of the mineral particles. This structural water layer has been inferred, but direct spectroscopic evidence of this interstitial water is given here. An ordered structural water layer sandwiched between the mineral and the organic collagen fibers may affect the biomechanical properties of this complex composite material. [source] Electrospray and matrix-assisted laser desorption/ionization mass spectral characterization of linear single nylon-6 oligomersJOURNAL OF MASS SPECTROMETRY (INCORP BIOLOGICAL MASS SPECTROMETRY), Issue 2 2001Lu Shan Abstract Synthetic nylon-6 single molecular mass oligomers were studied by matrix-assisted laser desorption/ionization (MALDI) and electrospray ionization (ESI) mass spectrometry. These oligomers, considered as model compounds for the study of nylon-6 polymers, gave good mass spectrometric results using both MALDI and ESI. In spite of the gentle nature of both techniques, the MALDI and ESI spectra showed evidence of end-group cleavage from the oligomer chains. MALDI-MS was found to give similar fragmentation patterns for all of the oligomer samples. An increase in doubly charged ion signals with increasing oligomer mass was observed in the ESI mass spectra, as was end-group fragmentation. Signals from oligomer clusters were observed in ESI-MS for the dimer, tetramer and hexamer, most likely due to non-covalent bonding among the low-mass oligomer molecules. Copyright © 2001 John Wiley & Sons, Ltd. [source] Phosphothioated oligodeoxynucleotides induce nonspecific effects on neuronal cell adhesion in a growth substrate-dependent manner,JOURNAL OF NEUROSCIENCE RESEARCH, Issue 8 2009Eitan Okun Abstract Synthetic phosphothioated (PTO) oligodeoxynucleotide (ODN) sequences are commonly used for a variety of applications that benefit from nuclease protection. The PTO modification is implemented mainly in antisense ODN, but also in ODN that were shown to activate members of the toll-like receptor (TLR) family such as TLR3 (poly-I:C), TLR8 (ssRNA), and TLR9 (CpG). Neurons are routinely plated on surfaces coated with either cationic substances such as poly-L-ornithine (PLO), polyethylenimine (PEI), poly-L-lysine or ECM components such as laminin, collagen, or fibronectin. We found that PTO-ODN aimed at activating TLR9 induces a non-TLR9-specific detachment phenotype in cortical neurons plated on either laminin or PEI, but not on PLO. This phenotype was correlated with decreased viability and was partially inhibited when caspase-3 was inhibited with Ac-DEVD-CMK. This finding suggests that the use of PTO-ODN can cause nonspecific effects on cell adhesion that could compromise interpretation of data from experiments using PTO-ODN. © 2009 Wiley-Liss, Inc. [source] Book News: Microthermal Field-Flow Fractionation: Analysis of Synthetic, Natural, and Biological Macromolecules and Particles.JOURNAL OF SEPARATION SCIENCE, JSS, Issue 5-6 2009Edited by Josef Janca [source] Microwave-Assisted Dimroth Rearrangement of Thiazines to Dihydropyrimidinethiones: Synthetic and Mechanistic AspectsMOLECULAR INFORMATICS, Issue 5-6 2006Abstract The Dimroth rearrangement of a set of substituted 2-amino-6H -1,3-thiazines into 3,4-dihydropyrimidine-2-thiones was investigated. The rearrangements were carried out under microwave irradiation conditions in batch or continuous flow format, employing either toluene or 1-methyl-2-pyrrolidone as solvent. Thiazines bearing an ester group at the C5 position rearranged at a considerably higher temperature than derivatives without substituents at this position into the corresponding pyrimidinethiones. This strictly thermal rearrangement was studied in detail using differential scanning calorimetry and density functional theory computational methods. The reaction pathway involves a zwitterionic intermediate. [source] Accurate fundamental parameters for lower main-sequence starsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 1 2006Luca Casagrande ABSTRACT We derive an empirical effective temperature and bolometric luminosity calibration for G and K dwarfs, by applying our own implementation of the Infrared Flux Method to multiband photometry. Our study is based on 104 stars for which we have excellent BV(RI)CJHKS photometry, excellent parallaxes and good metallicities. Colours computed from the most recent synthetic libraries (ATLAS9 and MARCS) are found to be in good agreement with the empirical colours in the optical bands, but some discrepancies still remain in the infrared. Synthetic and empirical bolometric corrections also show fair agreement. A careful comparison to temperatures, luminosities and angular diameters obtained with other methods in the literature shows that systematic effects still exist in the calibrations at the level of a few per cent. Our Infrared Flux Method temperature scale is 100-K hotter than recent analogous determinations in the literature, but is in agreement with spectroscopically calibrated temperature scales and fits well the colours of the Sun. Our angular diameters are typically 3 per cent smaller when compared to other (indirect) determinations of angular diameter for such stars, but are consistent with the limb-darkening corrected predictions of the latest 3D model atmospheres and also with the results of asteroseismology. Very tight empirical relations are derived for bolometric luminosity, effective temperature and angular diameter from photometric indices. We find that much of the discrepancy with other temperature scales and the uncertainties in the infrared synthetic colours arise from the uncertainties in the use of Vega as the flux calibrator. Angular diameter measurements for a well-chosen set of G and K dwarfs would go a long way to addressing this problem. [source] Reconstruction of an atmospheric tracer source using the principle of maximum entropy.THE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 610 2005II: Applications Abstract A new method of performing the source inversion of a passive tracer at continental scale was proposed in Part I of this two-part paper. The method made use of prior information, general or specific (depending on the situation), to perform a better reconstruction using only the prior information and the field measurements of the tracer. In this paper the method is tested on its first applications. It is used on several test examples, using the meteorological conditions of the European Joint Research Centre ETEX-I campaign. The retrieval of a temporal profile of emission from a source whose location is known is studied before testing the method on a full reconstruction of the space,time profile of the source. Synthetic, but also real-measurement, inversions are tested, thanks to the extension of the formalism to noisy data. Copyright © 2005 Royal Meteorological Society [source] Synthetic ,-Helix Mimetics as Agonists and Antagonists of Islet Amyloid Polypeptide Aggregation,ANGEWANDTE CHEMIE, Issue 4 2010Ishu Saraogi Gespaltene Persönlichkeit: Verschiedene oligoamidbasierte Helixmimetika binden an komplementäre Helixmotive in Insel-Amyloidpolypeptid (IAPP), einem Protein, das mit Typ-II-Diabetes in Zusammenhang gebracht wird. Ohne Lipid beschleunigen sie die IAPP-Amyloidbildung, lipidkatalysiert dagegen inhibieren sie sie. hIAPP=humanes IAPP. [source] Synthetic, spectral as well as in vitro antimicrobial studies on some bismuth(III) bis(N,N -dialkyldithiocarbamato) alkylenedithiophosphatesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 4 2010H. P. S. Chauhan Abstract Mixed sulfur donor ligand complexes of the type bismuth(III) bis(N,N -dialkyldithiocarbamato) alkylenedithiophosphate, [R2NCS2]2BiS2POGO [where R = CH3 and C2H5; G = -CH2 -C(C2H5)2 -CH2 -, -CH2 -C(CH3)2 -CH2 -, -CH(CH3)-CH(CH3)- and -C(CH3)2 -C(CH3)2 -] were synthesized in 1:1 molar ratio of bismuth(III) bis(N,N -dialkyldithiocarbamate) chloride and ammonium alkylenedithiophosphate in refluxing benzene and characterized by melting point, molecular weight determinations, elemental analysis (C, H, N, Bi and S) and spectral [UV, IR,NMR (1H,13C and 31P) and powder X ray diffraction] studies; all these studies were in good agreement with the synthesized complexes. These newly synthesized derivatives are yellow and brown colored solids and are soluble in common organic solvents like benzene, chloroform, dichloromethane and DMF. Based on the physicochemical and spectral studies, a tentative structure of these newly synthesized complexes was assigned and the average particle size of the synthesized complexes determined by powder XRD, showing that nano range polycrystalline particles were formed with a monoclinic crystal system. These complexes were also screened for their antimicrobial activities using the well diffusion method. The free ligands as well as their mixed metal complexes were tested in vitro against four bacterial strains: two Gram-positive, Staphylococcus aureus (ATCC 9144) (G+) and Bacillus subtilis (ATCC 6051), (G+) and two Gram-negative, Escherichia coli (ATCC 9637) (G,) and Pseudomonas aeruginosa (ATCC 25619) (G,) to assess their antimicrobial properties. The results were indeed positive and exhibited good antibacterial effects. Chloroamphenicol used as a standard for comparison and synthesized complexes showed good antibacterial effects over chloroamphenicol. On the basis of these studies, the synthesized complexes help to understand the different structural and biological properties of main group elements with sulfur donor ligands. Copyright © 2010 John Wiley & Sons, Ltd. [source] Synthetic and antimicrobial studies on new gold(I) complexes of imidazolidin-2-ylidenesAPPLIED ORGANOMETALLIC CHEMISTRY, Issue 7 2004smail Özdemir Abstract Six new 1,3-diorganylimidazolidin-2-ylidene (NHC) gold(I) complexes of the type [Au(NHC)2]+ (1,6), were synthesized by reacting [AuCl(PPh)3] with 1,3-dimesitylimidazolidin-2-ylidene or bis(1,3-dialkylimidazolidin-2-ylidene). The complexes 1,6 were fully characterized by elemental analyses and spectroscopic data. The placement of mesityl or para-substituted benzyl groups on the nitrogen atoms of the ring of the complexes leads to the particularly active antibacterial agents evaluated in this work. It is worth noting that the p -methoxybenzyl derivative (2) inhibited the growth of Pseudomona aeruginosa, Staphylococcus epidermidis, Staphylococcus aureus and Enterococcus faecalis with minimum inhibitory concentration (MIC) values of 3.12 µg ml,1, 6.25 µg ml,1, 3.12 µg ml,1 and 3.12 µg ml,1 respectively. In contrast, the analogous p -dimethylaminobenzyl derivative (3) is effective only against Escherichia coli (MIC = 3.12 µg ml,1). Copyright © 2004 John Wiley & Sons, Ltd. [source] SELECTED COCHRANE SYSTEMATIC REVIEWS Absorbable Synthetic Versus Catgut Suture Material for Perineal RepairBIRTH, Issue 2 2000C. Kettle A substantive amendment to this systematic review was last made on 19 May 1999. Cochrane reviews are regularly checked and updated if necessary. ABSTRACT Background and objectives: Approximately 70% of women will experience some degree of perineal trauma following vaginal delivery and will require stitches. This may result in perineal pain and superficial dyspareunia. The objective of this review was to assess the effects of absorbable synthetic suture material as compared with catgut on the amount of short- and long-term pain experienced by mothers following perineal repair. Search strategy: We searched the Cochrane Pregnancy and Childbirth Group trials register. Selection criteria: Randomised trials comparing absorbable synthetic (polyglycolic acid and polyglactin) with plain or chromic catgut suture for perineal repair in mothers after vaginal delivery. Data collection and analysis: Trial quality was assessed independently by two reviewers. Data were extracted by one reviewer and checked by the second reviewer. Main results: Eight trials were included. Compared with catgut, the polyglycolic acid and polyglactin groups were associated with less pain in first three days (odds ratio 0.62, 95% confidence interval 0.54,0.71). There was also less need for analgesia (odds ratio 0,63, 95% confidence interval 0.52,0.77) and less suture dehiscence (odds ratio 0.45, 95% confidence interval 0.29,0.70). There was no significant difference in long-term pain (odds ratio 0.81, 95% confidence interval 0.61,1.08). Removal of suture material was significantly more common in the polyglycolic acid and polyglactin groups (odds ratio 2.01, 95% confidence interval 1.56,2.58). There was no difference in the amount of dyspareunia experienced by women. Reviewers' conclusions: Absorbable synthetic suture material (in the form of polyglycolic acid and polyglactin sutures) for perineal repair following childbirth appears to decrease women's experience of short-term pain. The length of time taken for the synthetic material to be absorbed is of concern. A trial addressing the use of polyglactin has recently been completed and this has been included in this updated review. Citation: Kettle C, Johanson RB. Absorbable synthetic versus catgut suture material for perineal repair (Cochrane Review). In: The Cochrane Library, Issue 4, 1999, Oxford: Update Software. ,,, The preceding report is an abstract of regularly updated, systematic reviews prepared and maintained by the Cochrane Collaboration. The full texts of the reviews are available in The Cochrane Library (ISSN 1464-780X). Seehttp://www.update-software.com/cochrane.htmor contact Update Software,info@update.co.uk, for information on subscribing to The Cochrane Library in your area. Update Software Ltd, Summertown Pavilion, Middle Way, Oxford OX2 7LG, United Kingdom (Tel.: +44 1865 513902; Fax: +44 1865 516918). [source] Synthetic, Biocatalytic Acetylation and Antituberculosis Activity Evaluation Studies on (.+-.)-4-Alkyl-3,4-dihydro-3-,-hydroxyalkyl-2H-1,3-benzoxazines.CHEMINFORM, Issue 46 2003Ashok K. Prasad Abstract For Abstract see ChemInform Abstract in Full Text. [source] Synthetic and Antibacterial Studies on Some New Furanopeptides.CHEMINFORM, Issue 45 2003Boja Poojary Abstract For Abstract see ChemInform Abstract in Full Text. [source] ChemInform Abstract: Molecular Assembly of Zinc,Nickel Hybrid Porphyrin Dimer Using Synthetic 4,-Helix Polypeptides.CHEMINFORM, Issue 49 2002Mamoru Nango Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Purely Synthetic, Diversity Amenable Version of Norephedrine Thiols for the Highly Enantioselective Diethylzinc Addition to Aldehydes.CHEMINFORM, Issue 42 2001Ciril Jimeno Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: A Highly Chemoselective Oxidation of Alcohols to Carbonyl Products with Iodosobenzene Diacetate Mediated by Chromium(III)(salen) Complexes: Synthetic and Mechanistic Aspects.CHEMINFORM, Issue 2 2001Waldemar Adam Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Synthetic, Structural, and Theoretical Investigations of Alkali Metal Germanium Hydrides,Contact Molecules and Separated IonsCHEMISTRY - A EUROPEAN JOURNAL, Issue 4 2007Weijie Teng Dr. Abstract The preparation of a series of crown ether ligated alkali metal (M=K, Rb, Cs) germyl derivatives M(crown ether)nGeH3 through the hydrolysis of the respective tris(trimethylsilyl)germanides is reported. Depending on the alkali metal and the crown ether diameter, the hydrides display either contact molecules or separated ions in the solid state, providing a unique structural insight into the geometry of the obscure GeH3, ion. Germyl derivatives displaying MGe bonds in the solid state are of the general formula [M([18]crown-6)(thf)GeH3] with M=K (1) and M=Rb (4). The compounds display an unexpected geometry with two of the GeH3 hydrogen atoms closely approaching the metal center, resulting in a partially inverted structure. Interestingly, the lone pair at germanium is not pointed towards the alkali metal, rather two of the three hydrides are approaching the alkali metal center to display MH interactions. Separated ions display alkali metal cations bound to two crown ethers in a sandwich-type arrangement and non-coordinated GeH3, ions to afford complexes of the type [M(crown ether)2][GeH3] with M=K, crown ether=[15]crown-5 (2); M=K, crown ether=[12]crown-4 (3); and M=Cs, crown ether=[18]crown-6 (5). The highly reactive germyl derivatives were characterized by using X-ray crystallography, 1H and 13C,NMR, and IR spectroscopy. Density functional theory (DFT) and second-order Møller,Plesset perturbation theory (MP2) calculations were performed to analyze the geometry of the GeH3, ion in the contact molecules 1 and 4. [source] Synthetic and Spectroscopic Investigation of N -Acylated Sulfoximines,CHEMISTRY - A EUROPEAN JOURNAL, Issue 12 2004Christian P. R. Hackenberger Dr. Abstract N -Acylated sulfoximines display unique chemical properties. Various derivatives have been synthesized and investigated by NMR and IR spectroscopy. The results of these studies suggest that the bond between the sulfoximine nitrogen atom and the carbonyl group has a less pronounced double-bond character than the corresponding bond in an amide. This assumption is supported by the first X-ray crystal structure of a sulfoximidoyl derivative. Ab initio calculations (MP2/6-311++G**) provide further insight into the electronic nature of the N -acyl fragment. Studies of the chemical behavior of N -acylated sulfoximines indicate the presence of a highly electrophilic carbonyl group. Thus, the NC(O) bond can easily be cleaved under mild basic conditions, and the acidity of the hydrogen atoms , to the sulfoximine carbonyl group is high. As a consequence of the latter property, endo,endo -sulfoximidoyl norbornene derivatives readily isomerize to their endo,exo counterparts, and sulfoximine-containing pseudopeptides can easily epimerize at the stereogenic center next to the NC(O) carbonyl group. [source] | |||||||||||||||||||||||||||||||||||||||||||||||||