bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of mechanical bowel preparation on survival after colonic cancer resection
Authors: Collin Å , Jung B , Nilsson E , Påhlman L , Folkesson J 
Published: September 2014

Abstract

Background
A randomized study in 1999–2005 of mechanical bowel preparation (MBP) preceding colonic resection found no decrease in postoperative complications. The aim of the present study was to evaluate the long-term effect of MBP regarding cancer recurrence and survival after colonic resections.

Methods
The cohort of patients with colonic cancer in the MBP study was followed up for 10 years. Data were collected from registers run by the National Board of Health and Welfare. Register data were validated against information in patient charts. Cox proportional hazards model was used for multivariable analysis of factors predictive of cancer-specific survival.

Results
Register analysis showed significantly fewer recurrences, and better cancer-specific and overall survival in the MBP group. After validation, 839 of 1343 patients remained for analysis (448 MBP, 391 no MBP). Eighty (17·9 per cent) of 448 patients in the MBP group and 88 (22·5 per cent) of 391 in the no-MBP group developed a cancer recurrence (P = 0·093). The 10-year cancer-specific survival rate was 84·1 per cent in the MBP group and 78·0 per cent in the no-MBP group (P = 0·019). Overall survival rates were 58·8 and 56·0 per cent respectively (P = 0·186).

Conclusion
Patients receiving MBP before elective colonic cancer surgery had significantly better cancer-specific survival after 10 years.
Intramolecular Thioether Crosslinking of Therapeutic Proteins to Increase Proteolytic Stability
Authors: Lindgren Joel , Eriksson Karlström Amelie 
Published: September 2014

AbstractProtein‐based pharmaceuticals typically display high selectivity and low toxicity, but are also characterized by low oral availability, mainly because of enzymatic degradation in the gastrointestinal tract and poor permeability across the intestinal wall. One way to increase the proteolytic stability of peptides and proteins is by intramolecular crosslinking, such as the introduction of disulfide bridges. However, disulfide bridges are at risk of thiol‐disulfide exchange or reduction during production, purification, and/or therapeutic use, whereas thioether bridges are expected to be stable under the same conditions. In this study, thioether crosslinking was investigated for a 46 aa albumin‐binding domain (ABD) derived from streptococcal protein G. ABD binds with high affinity to human serum albumin (HSA) and has been proposed as a fusion partner to increase the in vivo half‐lives of therapeutic proteins. In the study, five ABD variants with single or double intramolecular thioether bridges were designed and synthesized. The binding affinity, secondary structure, and thermal stability of each protein was investigated by SPR‐based biosensor analysis and CD spectroscopy. The proteolytic stability in the presence of the major intestinal proteases pepsin (found in the stomach) and trypsin in combination with chymotrypsin (found in pancreatin secreted to the duodenum by the pancreas) was also investigated. The most promising crosslinked variant, ABD_CL1, showed high thermal stability, retained high affinity in binding to HSA, and showed dramatically increased stability in the presence of pepsin and trypsin/chymotrypsin, compared to the ABD reference protein. This suggests that the intramolecular thioether crosslinking strategy can be used to increase the stability towards gastrointestinal enzymes.
The Evolutionary Enhancement of Genotype–Phenotype Linkages in the Presence of Multiple Copies of Genetic Material
Authors: Uno Keisuke , Sunami Takeshi , Ichihashi Norikazu , Kazuta Yasuaki , Matsuura Tomoaki , Yomo Tetsuya 
Published: September 2014

AbstractGenetic evolutionary mechanisms employed by protolife developed without accompanying regulatory mechanisms for the amounts of genetic material in protocells. When many copies of genetic material are present, inactive copies generated by mutations are not effectively excluded through phenotypic selection. We demonstrate a model of gene evolution initiated with different amounts of DNA inside artificial protocells. We adopted transcription‐ and translation‐coupled RNA replication and liposome‐based in vitro compartmentalization. Despite the fact that the average number of DNA copies in each liposome was 6.4, DNA encoding active genes was maintained until the 16th selection round. Our experimental and theoretical results indicated that gene evolution can occur in the presence of multiple DNA copies. Most genetic material became junk code through gene mutations, and consequently the linkage between genotype and phenotype was enhanced through the associated decreases in active genetic material.
A Persulfide Analogue of the Nitrosothiol SNAP: Formation, Characterization and Reactivity
Authors: Artaud Isabelle , Galardon Erwan 
Published: September 2014

AbstractThe proposal of the post‐translational modification “S‐sulfhydration” as a major pathway for H2S‐induced signaling has recently shed light on persulfides. However, the study of these species is hampered by their instability under biologically relevant conditions; this requires generating them in situ immediately prior to use. The current methods to prepare persulfides in aqueous solution suffer from several drawbacks. In particular, their formation requires (or generates) hydrogen sulfide, thus resulting in difficulties in distinguishing polysulfide reactivity from that of H2S. Here we report the H2S‐free formation, characterization, and some biologically relevant reactions of a water‐soluble persulfide analogue of the nitrosothiol SNAP, a widely used nitric oxide donor.
A Site‐Isolated Organoruthenium‐/Organopalladium‐Bifunctionalized Periodic Mesoporous Organosilica Catalyzes Cascade Asymmetric Transfer Hydrogenation and Suzuki Cross‐Coupling
Authors: Zhang Dacheng , Xu Jianyou , Zhao Qiankun , Cheng Tanyu , Liu Guohua 
Published: September 2014

AbstractAn important challenge in asymmetric cascade reactions is solving the intrinsic incompatibility of two types of distinct organometallic complexes that participate in a one‐pot reaction. Herein, we develop an organoruthenium‐/organopalladium‐bifunctionalized periodic mesoporous organosilica and realize one‐pot cascade reactions of Ru‐catalyzed asymmetric transfer hydrogenation and Pd‐relay‐catalyzed cross‐coupling of haloacetophenones and arylboronic acids to various chiral biaryl alcohols, with quantitative conversions and up to 98 % enantioselectivity in an aqueous medium. This characteristics is attributed to the site‐isolated, uniformly distributed, well‐defined single‐site palladium and ruthenium active species. Furthermore, the heterogeneous catalyst is conveniently recovered and reused repeatedly for eight times without loss of its catalytic activity, showing particular attractiveness for practicing organic transformation.
Enriched‐Air Gasification of Refuse‐Derived Fuel in a Fluidized Bed: Effect of Gasifying Conditions and Bed Materials
Authors: Niu Miaomiao , Huang Yaji , Jin Baosheng , Sun Yu , Wang Xinye 
Published: September 2014

AbstractEnriched‐air gasification of refuse‐derived fuel (RDF) was carried out in a fluidized bed, investigating the effects of temperature, equivalence ratio (ER), oxygen percentage of enriched air (OP), and bed materials. For the bed material effect, calcined dolomite proved to be more effective for tar decomposition and resulted in higher CO and H2 contents. In a bed of high‐alumina bauxite, an increased ER tended to cause a greater decrease in syngas quality. For both bed materials, a higher temperature and OP favored the production of combustible gas and led to higher cold gas efficiency. Increasing the ER resulted in higher gas yields and carbon conversion but lowered the concentration of the combustible component. The ash content of the char increased with temperature and OP, while the volatile and fixed carbon contents were decreased. The optimum conditions suggested in this study were an ER of 0.22 and an OP of 44.7 % at 750–800 °C in a bed of calcined dolomite.
Energy Minimization in Cryogenic Packed Beds during Purification of Natural Gas with High CO2 Content
Authors: Ali Abulhassan , Maqsood Khuram , Syahera Nor , Shariff Azmi B. M. , Ganguly Saibal 
Published: September 2014

AbstractMinimization of energy consumption was explored for countercurrent switched cryogenic packed beds in which separation of CO2 and other components of natural gas can be achieved based on differences in freezing or desublimation points. Highly pure CO2 and methane were obtained after separation. An experimental setup for CO2 removal from natural gas was constructed and a detailed experimental study was conducted by changing different operating parameters. Compared to other cocurrent or jacket‐cooled constant‐temperature configurations, countercurrent switched beds provided optimal separation and energy efficiencies. The effects of important process parameters like initial temperature profiles of the cryogenic bed, feed composition, and feed flow rate on energy requirement, bed saturation, bed pressure, and cycling times were investigated. The energy requirement for cryogenic packed beds was compared with the conventional cryogenic distillation process.
Modular Molecules: Site‐Selective Metal Substitution, Photoreduction, and Chirality in Polyoxometalate Hybrids
Authors: Vonci Michele , Akhlaghi Bagherjeri Fateme , Hall Peter D. , Gable Robert W. , Zavras Athanasios , O'Hair Richard A. J. , Liu Yuping , Zhang Jie , Field Matthew R. , Taylor Matthew B. , Du Plessis Johan , Bryant Gary , Riley Mark , Sorace Lorenzo , Aparicio Pablo A. , López Xavier , Poblet Josep M. , Ritchie Chris , Boskovic Colette 
Published: September 2014

AbstractThe first members of a promising new family of hybrid amino acid–polyoxometalates have emerged from a search for modular functional molecules. Incorporation of glycine (Gly) or norleucine (Nle) ligands into an yttrium‐tungstoarsenate structural backbone, followed by crystallization with p‐methylbenzylammonium (p‐MeBzNH3+) cations, affords (p‐MeBzNH3)6K2(GlyH)[AsIII4(YIIIWVI3)WVI44YIII4O159(Gly)8‐ (H2O)14]⋅47 H2O (1) and enantiomorphs (p‐MeBzNH3)15(NleH)3 [AsIII4(MoV2MoVI2)WVI44YIII4O160(Nle)9(H2O)11][AsIII4(MoVI2WVI2)‐ WVI44YIII4O160(Nle)9(H2O)11] (generically designated 2: L‐Nle, 2 a; D‐Nle, 2 b). An intensive structural, spectroscopic, electrochemical, magnetochemical and theoretical investigation has allowed the elucidation of site‐selective metal substitution and photoreduction of the tetranuclear core of the hybrid polyanions. In the solid state, markedly different crystal packing is evident for the compounds, which indicates the role of noncovalent interactions involving the amino acid ligands. In solution, mass spectrometric and small‐angle X‐ray scattering studies confirm maintenance of the structure of the polyanions of 2, while circular dichroism demonstrates that the chirality is also maintained. The combination of all of these features in a single modular family emphasizes the potential of such hybrid polyoxometalates to provide nanoscale molecular materials with tunable properties.
New Classes of Ferromagnetic Materials with Exclusively End‐on Azido Bridges: From Single‐Molecule Magnets to 2 D Molecule‐Based Magnets
Authors: Alexandropoulos Dimitris I. , Cunha‐Silva Luís , Escuer Albert , Stamatatos Theocharis C. 
Published: September 2014

AbstractA new, flexible synthetic route, which does not require the co‐presence of any organic chelating/bridging ligand but only the “key” precursor Me3SiN3, has been discovered and led to a new class of inorganic materials containing exclusively end‐on azido bridges; the reported 3d‐metal clusters and coordination polymers exhibit ferromagnetic, single‐molecule magnet, and long‐range magnetic ordering properties.
Discovery of the Last Remaining Binary Platinum‐Group Pernitride RuN2
Authors: Niwa Ken , Suzuki Kentaro , Muto Shunsuke , Tatsumi Kazuyoshi , Soda Kazuo , Kikegawa Takumi , Hasegawa Masashi 
Published: September 2014

AbstractThe last remaining marcasite‐type RuN2 was successfully synthesized by direct chemical reaction between ruthenium and molecular nitrogen above the pressure of 32 GPa. For the first time, we found that Ru 4d is weakly hybridized with N 2p in the structure by using transmission electron microscopy equipped with electron‐energy‐loss spectroscopy. Our finding give important knowledge about the platinum‐group pernitride with respect to the chemical bonding between platinum‐group element and nitrogen.
Total Synthesis of (R,R,R)‐γ‐Tocopherol through Cu‐Catalyzed Asymmetric 1,2‐Addition
Authors: Wu Zhongtao , Harutyunyan Syuzanna R. , Minnaard Adriaan J. 
Published: September 2014

AbstractBased on the asymmetric copper‐catalyzed 1,2‐addition of Grignard reagents to ketones, (R,R,R)‐γ‐tocopherol has been synthesized in 36 % yield over 12 steps (longest linear sequence). The chiral center in the chroman ring was constructed with 73 % ee by the 1,2‐addition of a phytol‐derived Grignard reagent to an α‐bromo enone prepared from 2,3‐dimethylquinone.
Interactive Chemical Reactivity Exploration
Authors: Haag Moritz P. , Vaucher Alain C. , Bosson Maël , Redon Stéphane , Reiher Markus 
Published: September 2014

AbstractElucidating chemical reactivity in complex molecular assemblies of a few hundred atoms is, despite the remarkable progress in quantum chemistry, still a major challenge. Black‐box search methods to find intermediates and transition‐state structures might fail in such situations because of the high‐dimensionality of the potential energy surface. Here, we propose the concept of interactive chemical reactivity exploration to effectively introduce the chemist’s intuition into the search process. We employ a haptic pointer device with force feedback to allow the operator the direct manipulation of structures in three dimensions along with simultaneous perception of the quantum mechanical response upon structure modification as forces. We elaborate on the details of how such an interactive exploration should proceed and which technical difficulties need to be overcome. All reactivity‐exploration concepts developed for this purpose have been implemented in the samson programming environment.
Silicon Nanowire Photocathodes for Light‐Driven Electroenzymatic Synthesis
Authors: Lee Sahng Ha , Ryu Gyeong Min , Nam Dong Heon , Kim Jae Hong , Park Chan Beum 
Published: September 2014

AbstractThe photoelectroenzymatic synthesis of chemical compounds employing platinum nanoparticle‐decorated silicon nanowires (Pt‐SiNWs) is presented. The Pt‐SiNWs proved to be an efficient material for photoelectrochemical cofactor regeneration because the silicon nanowires absorbs a wide range of the solar spectrum while the platinum nanoparticle serve as an excellent catalyst for electron and proton transfer. By integrating the platform with redox enzymatic reaction, visible‐light‐driven electroenzymatic synthesis of L‐glutamate was achieved. Compared to electrochemical and photochemical methods, this approach is free from side reactions caused by sacrificial electron donors and has the advantage of applying low potential to realize energy‐efficient and sustainable synthesis of chemicals by a photoelectroenzymatic system.
Operando and In situ X‐ray Spectroscopies of Degradation in La0.6Sr0.4Co0.2Fe0.8O3−δ Thin Film Cathodes in Fuel Cells
Authors: Lai Samson Y. , Ding Dong , Liu Mingfei , Liu Meilin , Alamgir Faisal M. 
Published: September 2014

AbstractInformation from ex situ characterization can fall short in describing complex materials systems simultaneously exposed to multiple external stimuli. Operando X‐ray absorption spectroscopy (XAS) was used to probe the local atomistic and electronic structure of specific elements in a La0.6Sr0.4Co0.2Fe0.8O3−δ (LSCF) thin film cathode exposed to air contaminated with H2O and CO2 under operating conditions. While impedance spectroscopy showed that the polarization resistance of the LSCF cathode increased upon exposure to both contaminants at 750 °C, XAS near‐edge and extended fine structure showed that the degree of oxidation for Fe and Co decreases with increasing temperature. Synchrotron‐based X‐ray photoelectron spectroscopy tracked the formation and removal of a carbonate species, a Co phase, and different oxygen moieties as functions of temperature and gas. The combined information provides insight into the fundamental mechanism by which H2O and CO2 cause degradation in the cathode of solid oxide fuel cells.
Trade‐offs in seedling growth and survival within and across tropical forest microhabitats
Authors: Inman‐Narahari Faith , Ostertag Rebecca , Asner Gregory P. , Cordell Susan , Hubbell Stephen P. , Sack Lawren 
Published: September 2014

AbstractFor niche differences to maintain coexistence of sympatric species, each species must grow and/or survive better than each of the others in at least one set of conditions (i.e., performance trade‐offs). However, the extent of niche differentiation in tropical forests remains highly debated. We present the first test of performance trade‐offs for wild seedlings in a tropical forest. We measured seedling relative growth rate (RGR) and survival of four common native woody species across 18 light, substrate, and topography microhabitats over 2.5 years within Hawaiian montane wet forest, an ideal location due to its low species diversity and strong species habitat associations. All six species pairs exhibited significant performance trade‐offs across microhabitats and for RGR versus survival within microhabitats. We also found some evidence of performance equivalence, with species pairs having similar performance in 26% of comparisons across microhabitats. Across species, survival under low light was generally positively associated with RGR under high light. When averaged over all species, topography (slope, aspect, and elevation) explained most of the variation in RGR attributable to microhabitat variables (51–53%) followed by substrate type (35–37%) and light (11–12%). However, the relative effects of microhabitat differed among species and RGR metric (i.e., RGR for height, biomass, or leaf area). These findings indicate that performance trade‐offs among species during regeneration are common in low‐diversity tropical forest, although other mechanisms may better explain the coexistence of species with small performance differences.
Matrix liposomes: A solid liposomal formulation for oral administration
Authors: Pantze Silvia F. , Parmentier Johannes , Hofhaus Götz , Fricker Gert 
Published: September 2014

Liposomes can be used as oral dosage form to improve the bioavailability of both hydrophilic drugs, such as peptides and proteins and lipophilic drugs. But liposome dispersions are not very stable under the harsh conditions of the GI‐tract. Also a controlled release of embedded compounds is not possible. Therefore we developed a lipid based liposomal carrier system for peroral delivery of peptides. The lipid bilayer of standard egg‐PC/cholesterol liposomes were stabilized by gelatine. The gelatine also works as a thickening agent by forming a matrix in which liposomes are embedded. Liposomes were prepared by dual asymmetric centrifugation with the addition of gelatine. Size and size distribution of prepared liposomes with up to 20% gelatine achieved the same quality compared to conventional liposomes. Size and size distribution, encapsulation efficiency of different compounds and the dissolution behaviour of the solid dosage form in simulated intestinal fluid were examined. Matrix liposomes containing 20% gelatine showed an approximately linear release of liposomes. Moreover, the dissolution rate could be adjusted by modification of the gelatine concentration and the absolute amount of liposomes released at a certain time was found to be dose dependent.Practical applications: The new liposomal solid formulation can be useful for a controlled release of hydrophilic macromolecules as peptides and proteins after peroral administration. Liposomes embedded in a solid dosage form offer the possibility of a simple administration and exhibit higher storage stability compared to liposomes in dispersion.A composition of phospholidpids and gelatine leads to matrix liposomes prepared by dual asymmetric centrifugation. Dissolution of the solid liposomal formulation leads to a liposome release out of the dosage form. The dissolution rate can be adjusted by the concentration of gelatine.
Formation of a Zwitterionic Enolate from Tetramethylthiourea and Dimethyl Acetylenedicarboxylate
Authors: Wannebroucq Amélie , Pitak Mateusz B. , Coles Simon J. , Wallis John D. 
Published: September 2014

AbstractA zwitterionic tetrahydrothiophen‐3‐one derivative containing the enolate of a β‐keto ester located in the ring and a tetramethylamidinium group in a side chain is formed from tetramethylthiourea and dimethyl acetylenedicarboxylate by a surprising rearrangement reaction. Low‐temperature X‐ray crystallography shows weak intramolecular coordination of an enolate O atom by the amidinium group (O···C: 2.608 Å) and also a 1,5 S···O short contact (2.706 Å) due to electron delocalisation in a cis‐sulfanylacrylate grouping.
A Convergent Synthesis of Carbocyclic Sinefungin and its C‐5 Epimer
Authors: Ghosh Arun K. , Lv Kai 
Published: September 2014

AbstractA convergent synthesis of carbocyclic sinefungin (2), its C‐5 epimer 3a, and adenine‐modified derivative 3b is described. The key features of our approach include the use of commercially available L‐methionine and readily available (1R,4S)‐4‐hydroxy‐2‐cyclopentenyl acetate as starting materials, a cross‐metathesis reaction, an enzymatic kinetic resolution, and a Staudinger reduction. The current synthesis is flexible and, therefore, provides convenient access to the synthesis of various carbocyclic sinefungin analogues for biological evaluation.
The Nazarov Cyclization: A Valuable Method to Synthesize Fully Substituted Carbon Stereocenters
Authors: Wenz Donald R. , Read de Alaniz Javier 
Published: September 2014

AbstractThe synthesis of fully substituted carbon stereocenters remains a challenging task in organic chemistry. Recent developments in the design of substrates that undergo the Nazarov cyclization have enabled this reaction to become a valuable way to form elaborately substituted cyclopentane rings containing fully substituted carbon stereocenters. Three major strategies have been utilized in this endeavor. Here we provide an overview of these three areas that should give insight into the usage of the Nazarov reaction for the challenging task of forming fully substituted carbon stereocenters.
One‐Pot Preparation of Chiral Carbacycles from Morita–Baylis–Hillman Carbonates by an Asymmetric Allylic Alkylation/Olefin Metathesis Sequence
Authors: Putaj Piotr , Tichá Iveta , Císařová Ivana , Veselý Jan 
Published: September 2014

AbstractAn operationally simple, one‐pot synthetic protocol for the formation of all‐carbon, highly substituted five‐ and six‐membered rings is described. In this two‐step procedure, an asymmetric allylic alkylation (AAA) of Morita–Baylis–Hillman (MBH) carbonates with allylmalononitrile, catalyzed by a chiral tertiary amine, is followed by a ring‐closing alkene metathesis (RCM) reaction. Products are obtained in high yields, and an excellent level of optical purity of some of the target compounds is achieved after just a single recrystallization.