bluuebunny/crossref_metadata_2025_split huggingface dataset:
Electrostatic calculations for assignment of infrared difference bands to carboxyl groups getting protonated during protein reactions
Authors: Hauser Karin 
Published: November 2005

AbstractFourier transform infrared (FTIR) difference spectroscopy is predestinated to monitor the protonation of carboxyl groups during protein reactions, making glutamic and aspartic amino acids unique to follow proton pathways. The absorption of the corresponding vibrations are clearly distinguishable from the absorption of other amino acids. However, the assignment to specific groups within the protein needs additional information, e.g., from induced spectral changes due to isotopic labeling or mutation. Here, the capability of electrostatic calculations to assign IR difference bands to specific carboxyl groups getting protonated is demonstrated by the ion pump mechanism of the sarcoplasmic reticulum Ca2+‐ATPase. Active Ca2+ transport is coupled to the hydrolysis of ATP. Two Ca2+ ions are transported per ATP hydrolysed and two or three H+ ions are countertransported. FTIR difference spectra show that during the Ca2+ release step, carboxyl groups become protonated. Multiconformation continuum electrostatic calculations (MCCE) have been carried out to determine the equilibrium distribution of residue ionization and side chain conformation in dependence of pH. Available structural X‐ray data from the calcium‐bound and the calcium‐free state allows us to simulate the transition between the two states monitored in the IR difference spectra. Exemplarily for Asp 800, ligand of both calcium ions, it is shown that MCCE calculations can identify this specific Asp to contribute to the IR bands and therefore to take part in the proton countertransport of the Ca2+‐ATPase. In addition, an energy analysis can be performed to understand what interactions shift the pKa. © 2005 Wiley Periodicals, Inc. Biopolymers 82: 430–434, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Fast and versatile microwave‐assisted intramolecular Heck reaction in peptide macrocyclization using microwave energy
Authors: Byk Gerardo , Cohen‐Ohana Mirit , Raichman Daniel 
Published: November 2005

AbstractWe have revisited the intramolecular Heck reaction and investigated the microwave‐assisted macrocyclization on preformed peptides using a model series of ring‐varying peptides acryloyl‐Gly‐[Gly]n‐Phe(4‐I)NHR; n  0–4. The method was applied to both solution and solid supported cyclizations. We demonstrate that the intramolecular Heck reaction can be performed in peptides both in solution and solid support using a modified domestic microwave within 1 to 30 minutes in DMF under reflux with moderate yields ranging from 15 to 25% for a scale between 2–45 mg of linear precursors. The approach was applied to the synthesis of a constrained biologically relevant peptidomimetic bearing an Arg‐Gly‐Asp (RGD) sequence. These results make the microwave‐assisted Heck reaction an attractive renovated approach for peptidomimetics. © 2005 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 84: 274–282, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Interfacial behavior of cytoplasmic and mitochondrial creatine kinase oligomeric states
Authors: Vernoux Nathalie , Granjon Thierry , Marcillat Olivier , Besson Françoise , Vial Christian 
Published: November 2005

AbstractAdsorption to the air/water interface of isoenzymes of creatine kinase was investigated using surface pressure–area isotherms and Brewster angle microscopy (BAM) observations. Octameric mitochondrial creatine kinase (mtCK) exhibits a significant affinity for the air/water interface. Whatever the mode of formation of the interfacial film, i.e., injection of the protein in the subphase or spreading onto the buffer surface, the final arrangement and conformation adopted by mtCK molecules lead to a similar result. In contrast, the dimeric isoenzymes mtCK and cytosolic MMCK do not induce any surface pressure variation. However, when the subphase contains 0.3M NaCl, both isoenzymes adsorb to the interface. When treated with 0.8 or 3M GdnHCl, muscle creatine kinase (MMCK) becomes surface active and occupies a greater surface than mtCK. This result contrasts with previous observations, often derived from monomeric proteins, that their surface activity is increased upon unfolding. It underlines the possible influence exerted by the protein oligomeric state on its interfacial activity. At a subphase pH of 8.8, which corresponds to the pI of octameric mtCK, the profiles of the isotherms obtained with dimeric and octameric states and the resistance to compression of the protein monolayers are significantly affected when compared to those recorded at pH 7.4. These data suggest that the octamer is more hydrophobic than the dimer and may contribute to explaining why octamers bind to the inner mitochondrial membrane while dimers do not. © 2005 Wiley Periodicals, Inc. Biopolymers 81: 270–281, 2006This article was originally published online as an accepted preprint. The “Published Online” date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com
Prevention of thermal induced aggregation of cytochrome c at isoelectric pH values by polyanions
Authors: Fedunová Diana , Antalík Marián 
Published: November 2005

AbstractDifferential scanning calorimetry, viscometry, optical and CD spectroscopy were used to characterize the influence of two polyanions, poly(vinylsulfate) (PVS), and poly(4‐styrene‐sulfonate) (PSS) on thermal transition reversibility of ferricytochrome c at or near isoelectric pH. In these conditions, both PVS and PSS enhance the thermal transition reversibility of cytochrome c by preventing the aggregation of denatured protein molecules. Data indicate that the polyanions are in complex with cytochrome c that is stabilized by synergistic effect of Coulombic and non‐Coulombic interactions. © 2005 Wiley Periodicals, Inc.
Causes and outcomes of pouch excision after restorative proctocolectomy
Authors: Prudhomme M , Dehni N , Dozois R R , Tiret E , Parc R 
Published: November 2005

Abstract

Background
Pouch failure occurs in up to 10 per cent of patients after ileal pouch–anal anastomosis (IPAA). The aims of this study were to determine the reasons for pouch excision and to evaluate the outcome of the perineal wound after pouch excision.

Methods
Between 1984 and 2002, 91 patients with severe ileal pouch dysfunction were treated. This was a retrospective analysis of data collected prospectively from 24 patients who underwent pouch excision.

Results
Patients were grouped according to the final histological diagnosis. Fourteen patients with Crohn's disease developed extensive fistulous disease and/or recurrent abscesses, of whom six had a persistent perineal sinus after pouch excision. Five patients had familial adenomatous polyposis, in three of whom desmoid tumours were the cause of failure. Three patients had chronic ulcerative colitis and developed recurrent pelvic sepsis. Finally, two patients with multiple colorectal adenocarcinoma developed recurrent cancer (one) or sepsis (one).

Conclusion
Sepsis was the principal reason for pouch excision and was usually associated with recrudescent Crohn's disease in the pouch. Perineal wound healing was problematic after pouch excision for Crohn's disease.
Evaluation of outcome of laparoscopic colorectal resection with POSSUM, Portsmouth POSSUM and colorectal POSSUM
Authors: Law W L , Lam C M , Lee Y M 
Published: November 2005

Abstract

Background
This study evaluated the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM), Portsmouth (P) POSSUM and colorectal (CR) POSSUM in laparoscopic colorectal resection.

Methods
Observed mortality and morbidity rates in 400 patients who underwent laparoscopic colorectal resection were compared with those predicted by POSSUM, P-POSSUM and CR-POSSUM.

Results
Observed mortality and morbidity rates were 0·5 and 19·0 per cent respectively. Mortality rates predicted by POSSUM, P-POSSUM and CR-POSSUM were 10·8, 4·0 and 5·6 per cent respectively, and the morbidity rate predicted by POSSUM was 43·0 per cent. The predicted and observed mortality and morbidity rates showed significant lack of fit. The conversion rate to open surgery was 11·5 per cent. The mortality rate for patients having conversion was 2 per cent and was not significantly different to that predicted by P-POSSUM (4 per cent; P = 0·493) or CR-POSSUM (5 per cent; P = 0·370). In this group, the observed and POSSUM-predicted morbidity rates were also similar (43 versus 48 per cent respectively; P = 0·104).

Conclusion
POSSUM, P-POSSUM and CR-POSSUM overestimated mortality and morbidity in patients who underwent laparoscopic colorectal resection. However, the mortality rate in patients who required conversion fitted the models of P-POSSUM and CR-POSSUM, and the morbidity rate was comparable to that predicted by POSSUM.
Synthesis and Two‐photon Photolysis of 6‐(ortho‐Nitroveratryl)‐Caged IP3 in Living Cells
Authors: Kantevari Srinivas , Hoang Caroline J. , Ogrodnik Jakob , Egger Marcel , Niggli Ernst , Ellis‐Davies Graham C. R. 
Published: November 2005

AbstractThe synthesis of a photolabile derivative of inositol‐1,4,5‐trisphosphate (IP3) is described. This new caged second messenger (6‐ortho‐nitroveratryl)‐IP3 (6‐NV‐IP3) has an extinction coefficient of 5000 M−1 cm−1 at 350 nm, and a quantum yield of photolysis of 0.12. Therefore, 6‐NV‐IP3 is photolyzed with UV light about three times more efficiently than the widely used P4(5)‐1‐(2‐nitrophenyl)ethyl‐caged IP3 (NPE‐IP3). 6‐NV‐IP3 has a two‐photon cross‐section of about 0.035 GM at 730 nm. This absorbance is sufficiently large for effective two‐photon excitation in living cells at modest power levels. Using near‐IR light (5 mW, 710 nm, 80 MHz, pulse‐width 70 fs), we produced focal bursts of IP3 in HeLa cells, as revealed by laser‐scanning confocal imaging of intracellular Ca2+ concentrations. Therefore, 6‐NV‐IP3 can be used for efficient, subcellular photorelease of IP3, not only in cultured cells but also, potentially, in vivo. It is in the latter situation that two‐photon photolysis should reveal its true forte.
Continuous Matrix‐assisted Refolding of Inclusion‐body Proteins: Effect of Recycling
Authors: Schlegl R. , Necina R. , Jungbauer A. 
Published: November 2005

AbstractA recombinant therapeutic protein expressed inEscherichia coliin form of inclusion bodies was used as a model system for comparative studies on the refolding efficiencies obtained by continuous matrix‐assisted refolding or batch‐dilution in a stirred tank reactor. Due to the strong aggregation tendency the refolding yield after dilution into an appropriate renaturation buffer was only 10 % at a protein concentration of 0.1 mg/mL. To improve the yield of active protein matrix‐assisted refolding using size‐exclusion chromatography was tested. A preparative continuous annular chromatography system (PCAC) equipped with a size‐exclusion resin was used for continuous processing of the solubilized unfolded protein. As the protein passed through the column, it was separated from the chaotropic agent and started to regain its native structure. Tightly bound aggregates produced during the refolding reaction were continuously removed from the rotating bed by 6 M guanidine‐hydrochloride. The aggregate fraction was recycled to the feed stream after concentrating by ultradiafiltration to increase the amount of refolded protein. The refolding yield of 27 % without recycling was increased to 45 % at a recycling rate of 0.51 at a protein concentration of 1 mg/mL. The stability of the reactor under continuous operation was shown for 15 hours without any significant loss of refolding efficiency or chromatographic resolution. Interdependencies of operational parameters such as protein concentration, loading factor and recycling rate on throughput of refolded protein are shown.
High Throughput Screening of Chromatographic Phases for Rapid Process Development
Authors: Bensch M. , Schulze Wierling P. , von Lieres E. , Hubbuch J. 
Published: November 2005

AbstractThe necessity of being “first on the market” paired with the need to cut production costs highlights the need for strategies and techniques allowing a fast process development while at the same time covering a high number of potential process parameters in order to reach an optimal process sequence. This can only be met by the use of high throughput screening (HTS) techniques. In this paper HTS applications presently applied in bioprocess development are reviewed, their use in chromatographic process parameter evaluation is discussed and concepts for the rational design of HTS experiments are presented. A rational approach for chromatographic parameter screening comprehends an initial screening procedure for ligand selection followed by the incorporation of specific adsorbent features using HTS pipetting systems finalized by a fine tuning step using packed mini‐columns. The analytical part of these screening techniques clearly sets the bottleneck of these procedures with a trade off between analytical information and analysis time. Finally, intelligent HTS strategies should in addition include efficient data processing paired with modern tools for design of experiments or model based process design.
Electrostatic Interaction Chromatography Process for Protein Separations: Impact of Engineering Analysis of Biorecognition Mechanism on Process Optimization
Authors: Yamamoto S. 
Published: November 2005

AbstractA simple model for obtaining important information on the retention and the resolution of proteins by electrostatic interaction chromatography is described. The relationships among different definitions of distribution coefficients are explained in detail. The method employs a linear gradient elution experiment, in which a salt concentration is increased linearly with time at a fixed pH. The experimental data for electrostatic interaction chromatography and hydroxyapatite chromatography of proteins have shown that the number of binding sites values (B) determined from the experimental data as a function of pH can provide instructive information on the retention and the optimization of protein separations.
Multiple factor analysis with confidence ellipses: a methodology to study the relationships between sensory and instrumental data
Authors: Pagés Jérôme , Husson François 
Published: November 2005

AbstractThis paper describes a methodology to simultaneously analyse instrumental and sensory variables. The methodology is based on multiple factor analysis (MFA) which provides dimensions of variability of the products, connected to the two types of variables. The MFA graphics are constructed with confidence ellipses around the products in order to visualize the uncertainty in their position. These ellipses are drawn using a bootstrap procedure on the basis of both the instrumental and the sensory data or on the basis of the sensory data only. Copyright © 2005 John Wiley & Sons, Ltd.
PLS regression, PLS path modeling and generalized Procrustean analysis: a combined approach for multiblock analysis
Authors: Tenenhaus Michel , Vinzi Vincenzo Esposito 
Published: November 2005

AbstractA situation where J blocks of variables are observed on the same set of individuals is considered in this paper. A factor analysis logic is applied to tables instead of variables. The latent variables of each block should well explain their own block and, at the same time, the latent variables of same order should be as positively correlated as possible to improve interpretation. The paper first (1) reviews the main methods for multiblock analysis based on a criterion to be optimized, (2) describes the hierarchical PLS path modeling algorithm and (3) recalls that it allows one to recover some usual multiblock analysis methods. It is then supposed that the number of latent variables can be different from one block to another and that these latent variables are orthogonal. PLS regression and PLS path modeling are used for this situation. The relation between Horst's generalized canonical correlation analysis and generalized Procrustean analysis for this specific application is also studied. The approach is illustrated by an example from sensory analysis. Copyright © 2005 John Wiley & Sons, Ltd.
Comparing and predicting sensory profiles from NIRS data: use of the GOMCIA and GOMCIA‐PLS multiblock methods
Authors: Vivien Myrtille , Verron Thomas , Sabatier Robert 
Published: November 2005

AbstractSequential multiblock component and regression methods are used to analyse pea sensory data. First the repeatability of sensory profiles is studied with the generalized orthogonal multiple co‐inertia analyis (GOMCIA) method. Then a calibration model is built to predict the averaged sensory profiles from near‐infrared spectroscopy (NIRS) data by means of the GOMCIA partial least squares (GOMCIA‐PLS) method. It is proposed to split the NIRS data into blocks and search the most influential block in the calibration model in order to select spectral wavelengths. This approach is compared with a PLS regression model. It is shown that a PLS regression model can be less efficient than a multiblock regression model in terms of prediction. Copyright © 2005 John Wiley & Sons, Ltd.
Independent component analysis and regression applied on sensory data
Authors: Westad Frank 
Published: November 2005

AbstractIn this paper, independent component analysis (ICA) and a partial least squares implementation of independent component regression (ICR) were applied on two sensory data sets. A brief introduction to the theory of ICA is presented, and how to find the optimal model rank is discussed. The effect of the number of independent components extracted is illustrated by comparison of ICA loadings from models with different numbers of components. Principal component analysis (PCA) and ICA were employed on the sensory data, and these methods are interpreted based on explained variance for the components and groupings of the sensory attributes. Significance testing on each sensory attribute for the components gave valuable information about the relevance in interpreting the individual attributes and components. ICA was also applied for regression purposes similarly to principal component regression (PCR) and partial least squares regression (PLSR). An algorithm which combines ICA and PLSR (IC‐PLSR) is presented. Single‐response IC‐PLSR seemed to be a promising complementary method to PLSR in extracting informative and valid components. Copyright © 2005 John Wiley & Sons, Ltd.
Solid‐Phase Oligosaccharide Synthesis of a Small Library of N‐Glycans
Authors: Jonke Simon , Liu Ke‐gang , Schmidt Richard R. 
Published: November 2005

AbstractSolid‐phase oligosaccharide synthesis is based on a hydroxymethylbenzyl benzoate spacer linker which is connected to the Merrifield resin (1 P). Glycosylation was performed with O‐glycosyl trichloroacetimidates of glucosamine, mannose, and galactose permitting chain extension (2e, 5e), branching (4b, 7b, 8b), and chain termination (3t, 6t, 9t) with the use of O‐benzyl, O‐benzoyl, and N‐dimethylmaleoyl as permanent and O‐fluorenylmethoxycarbonyl (Fmoc) and O‐phenoxyacetyl (PA) as temporary protecting groups. The steps required on solid phase are i) glycosylation under TMSOTf catalysis, ii) selective cleavage of the temporary protecting groups, Fmoc with NEt3 and PA with 0.5 equivalents of NaOMe in CH2Cl2/MeOH, and iii) product cleavage from the resin with 4.0 equivalents of NaOMe in CH2Cl2/MeOH and following O‐acetylation for convenient product isolation. Thus a highly successful synthesis of a small library of seventeen N‐glycan structures was made possible comprising the N‐glycan pentasaccharide core structure 53 and two further chain extended hexa‐ and heptasaccharide N‐glycans with a glucosamine or a lactosamine residue, respectively, which is attached to one of the mannose residues of the core structure (56 and 59).
A New Approach to Enantiopure C3‐Symmetric Molecules
Authors: Castaldi M. Paola , Gibson Susan E. , Rudd Matthew , White Andrew J. P. 
Published: November 2005

AbstractChiral base chemistry has been used to create three chiral centres in one pot on a C3‐symmetric substrate. The potential of this new approach to C3‐symmetric molecules is exemplified by the creation of an enantiopure C3v‐symmetric triol, triphosphane and tripyridine. A ruthenium complex of the last compound has been studied by X‐ray crystallography.
The Influence of the Concentration of Sb Ions onto the Local Crystal and Electronic Structures of CuCr2‐xSbxS4 (x = 0.3, 0.4, 0.5) Studied by XANES and EXAFS Measurements and LAPW Numerical Calculations.
Authors: Zajdel P. , et al. et al. 
Published: November 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
A Flexible and Versatile Strategy for the Covalent Immobilization of Chiral Catalysts Based on Pyridinebis(oxazoline) Ligands.
Authors: Cornejo Alfonso , Fraile Jose M. , Garcia Jose I. , Gil Maria J. , Luis Santiago V. , Martinez‐Merino Victor , Mayoral Jose A. 
Published: November 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Acyclic Amino Acid‐Catalyzed Direct Asymmetric Aldol Reactions: Alanine, the Simplest Stereoselective Organocatalyst.
Authors: Cordova Armando , Zou Weibiao , Ibrahem Ismail , Reyes Efraim , Engqvist Magnus , Liao Wei‐Wei 
Published: November 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Reaction of 1,3‐Dicarbonyl Compounds with o‐Phenylenediamine or 3,3′‐Diaminobenzidine in Water or under Solvent‐Free Conditions via Microwave Irradiation.
Authors: Wang Zhong‐Xia , Qin Hua‐Li 
Published: November 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
A New Method for the Synthesis of Carboxylic Esters and Lactones with Di‐2‐thienyl Carbonate (2‐DTC) by the Promotion of DMAP and Iodine.
Authors: Oohashi Yoshiaki , Fukumoto Kentarou , Mukaiyama Teruaki 
Published: November 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Nucleophilic Addition to Acetylenes in Superbasic Catalytic Systems. Part 8. Fluoride Cesium Containing Systems, Efficient Catalysts for Alkanols Vinylation.
Authors: Oparina L. A. , Shaikhudinova S. I. , Parshina L. N. , Vysotskaya O. V. , Preiss Th. , Henkelmann J. , Trofimov B. A. 
Published: November 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
1,4‐Conjugate Additions of Methoxyamine and 1,1‐Dimethylhydrazine to Hex‐3‐yne‐2‐one: A Facile Synthesis of Functionalized Isoxazole and Pyrazole Precursors.
Authors: Sauers Ronald R. , Van Arnum Susan D. 
Published: November 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Simple Procedure for the Synthesis of Arylmethylenemalononitrile Without Catalyst.
Authors: Wang Xiang‐Shan , Zeng Zhao‐Sen , Li Yu‐Ling , Shi Da‐Qing , Tu Shu‐Jiang , Wei Xian‐Yong , Zong Zhi‐Min 
Published: November 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
A New Type of Uniformly Stacked Phase in Tetrathiapentalene‐Based Organic Metals.
Authors: Bando Yoshimasa , Matsuzawa Takahiro , Takashita Norihiro , Kawamoto Tadashi , Mori Takehiko , Yamada Jun‐ichi 
Published: November 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.
Fluorine‐Containing Heterocycles. Part 2. Synthesis and Reactions of New Thieno[2,3‐b]pyridine Derivatives Bearing Trifluoromethyl Group.
Authors: Abdel‐Rahman Abdu E. , Bakhite Etify A. , Al‐Taifi Elham A. 
Published: November 2005

AbstractFor Abstract see ChemInform Abstract in Full Text.