bluuebunny/crossref_metadata_2025 huggingface dataset:
Thermal decomposition of natural fibers: Global kinetic modeling with nonisothermal thermogravimetric analysis
Authors: Yao Fei , Wu Qinglin , Zhou Dingguo
Published: June 2009

The modeling of thermal decomposition process of ten natural fibers commonly used in polymer composite industry was performed by assuming a global model occurring within the entire degradation range with consideration of fiber as one pseudocomponent. Málek method with activation energy values previously obtained was applied to the modeling process. Careful calculation and evaluation indicated that, within an acceptable error limit of 5%, RO(n > 1) model can be used to describe the degradation process of most selected fibers well. The other kinetic parameters used include activation energy range of 160–170 kJ/mol; parameter n in RO(n > 1) = (1 − α)n of 3–4; and ln A between 35 and 42 ln s−1. Some condition limitations of the obtained model were also discussed. The model has practical significance in predicting fiber weight loss when the fiber is used in combination with engineering thermoplastics. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effects of expandable graphite and ammonium polyphosphate on the flame‐retardant and mechanical properties of rigid polyurethane foams
Authors: Meng Xian‐Yan , Ye Ling , Zhang Xiao‐Guang , Tang Pei‐Mei , Tang Jian‐Hua , Ji Xu , Li Zhong‐Ming
Published: June 2009

In this work, the effect of expandable graphite (EG) and ammonium polyphosphate (APP) on the flame retardancy and mechanical properties of the rigid polyurethane foam (RPUF) was studied. The results indicated that both EG and APP could effectively improve the flame retardancy of RPUF, while the retardancy of EG was better than APP. When the flame‐retardant loading was 15 wt %, the limited oxygen index (LOI) values of APP‐ and EG‐filled RPUF were 24.5 and 32 vol %, respectively. According to the LOI test, the optimal ratio of APP to EG in RPUF composites was 1 : 1 by weight, at which the LOI value of 15 wt % (APP + EG)/RPUF was 30.5 vol %. Thermal degradation test of RPUF composites by thermogravimetric analysis indicated that the addition of APP and EG to RPUF could lead to an increase in the amount of high‐temperature residue. Under the same conditions, the residue amount of EG/RPUF was less than that of APP/RPUF at the same temperature. Compression test and dynamic thermal mechanical analysis indicated that both the compressive strength and modulus decreased at a certain extent with the EG‐ or APP‐filled into RPUF, respectively, but with the mixture of EG and APP added into RPUF, the mechanical properties of these materials increased. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of low‐protein natural rubber latex: Effect of polyethylene glycol
Authors: Abhilash G. , Sabharwal S. , Dubey Abhinav , Paul Jose , John Honey , Joseph Rani
Published: June 2009

Low‐protein content natural rubber latex was produced by using a nonionic surfactant‐polyethylene glycol (PEG). Extractable protein content of natural rubber latex was found to decrease with PEG treatment and reduction increased with increase in the molecular weight of PEG. The low‐protein latex samples were characterized by tensile testing, Fourier transform infrared and thermogravimetric analysis. The results have shown 35% reduction in the extractable protein content, without any compromise on the mechanical properties of the latex; however, thermal stability of low‐protein latex was found to be reduced marginally with PEG treatment. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Properties of poly(vinyl chloride) and polyesteramides blends
Authors: Kalousková Radka , Markvart Ludìk , Kredatusová Jana , Brožek Jiří
Published: June 2009

Blends of poly(vinyl chloride) (PVC) and polyesteramides (PEA), based on ε‐caprolactam and ε‐caprolactone, were prepared to improve the notch impact strength of PVC. Miscibility of components was assessed from glass transition temperature and is limited by the amount of PEA in the blend and by the content of ε‐caprolactam structural units in PEA. The effects of the content and type of PEA on their thermal stability and notched impact strength were also investigated. The impact strength of the PVC blends reaches its maximum at an equimolar lactam to lactone units ratio in PEA; it decreases with increasing content of PEA in the blend. An admixture of a small amount of poly(ε‐caprolactam) as a compatibilizer made it possible to prepare PEA‐rich PVC blends, exhibiting twice as high notch impact strength, as compared to pure PVC. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Organic and aqueous compatible polystyrene–maleic anhydride copolymer ultra‐fine fibrous membranes
Authors: Cécile Corine , Hsieh You‐Lo
Published: June 2009

Polystyrene–maleic anhydride copolymer (PSMA, Mv= 700 kDa) was synthesized and efficiently processed into 400 to 600 nm diameter fibers via electrospinning from either 20 wt % dimethylformamide or 25 wt % dimethylsulfoxide solution. Crosslinking of PSMA was effective by adding glycerol and poly(vinyl alcohol) (PVA) (Mw = 31–50 kDa) in the dimethylformamide and dimethylsulfoxide solutions, respectively. The PSMA fibers containing glycerol at 29.4 mol% were auto‐crosslinked whereas those with 12.9 mol% (2 wt %) glycerol and 15.4 mol% (0.75 wt %) PVA required heating to induce intermolecular esterification. Heat‐induced crosslinking with glycerol was more effective in rendering the PSMA fibrous membranes insoluble in all solvents whereas that with PVA remained soluble in most solvents except for acetone and tetrahydrofuran. The crosslinked fibrous membranes had improved thermally stability and retained physical integrity upon exposure (2 hr at 40°C) to carbon disulfide, the solvent for Friedel‐Craft reactions of the styrene moiety. Hydrolysis (0.01N NaOH) of the auto‐crosslinked fibrous membrane significantly improved its hydrophilicity by reducing the water contact angles from 90.6° to 62.5° in a matter of seconds. These ultra‐high specific surface PSMA fibrous membranes have shown superior organic and aqueous solvent compatibility to be used as highly reactive and easily retrievable supports for solid‐phase synthesis. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
High shear strain rate rheometry of polymer melts
Authors: Kelly A. L. , Gough T. , Whiteside B. R. , Coates P. D.
Published: June 2009

The rheology of a range of polymer melts has been measured at strain rates above those attained during conventional rheometry using an instrumented injection molding machine. Deviations from shear thinning behavior were observed at high rates, and previously unreported shear thickening behavior occurred for some of the polymers examined. Measured pressure and volumetric throughputs were used to calculate shear and extensional viscosity at wall shear strain rates up to 107 s−1. Parallel plate rheometry and twin bore capillary rheometry were used to provide comparative rheological data at low and medium shear strain rates, respectively. Commercial grades of polyethylene, polypropylene, polystyrene, and PMMA were studied. Measured shear viscosity was found to follow Newtonian behavior at low rates and shear thinning power law behavior at intermediate strain rates. At shear strain rates approaching or above 106 s−1, shear viscosity reached a rate‐independent plateau, and in some cases shear thickened with further increase in strain rate. A relationship between the measured high strain rate rheological behavior and molecular structure was noted, with polymers containing larger side groups reaching the rate‐independent plateau at lower strain rates than those with simpler structures. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis of processible doped polyaniline‐polyacrylic acid composites
Authors: Gupta Bhavana , Prakash Rajiv
Published: June 2009

Processible composites of emeraldine salt form of polyaniline (PANI) with polyacrylic acid (PAA) are synthesized and studied for their structural, electrical, mechanical, thermal, and electrochemical properties. The processible conducting composites of various weight percentage from 20 wt % to 90 wt % (of PANI) have been prepared by mixing the PANI and PAA under vigorous stirring and sonication conditions. Self‐standing films of electroactive homogeneous composites are obtained by solution casting method. A significant improvement in processibility, crystallinity, and thermal stability is observed in the composites; however, the electrical conductivity decreased remarkably as the percentage of PANI is decreased in the composites. The 60 wt % PANI‐PAA composite showed crystalline structural property with orthorhombic crystal system and cell parameters as a = 5.93Å, b = 7.57Å, and c = 10.11Å. The 60 wt % PANI‐PAA composite also showed better thermal stability and highest capacitance amongst all the composites and used as an active material for development of electrochemical capacitors (parallel plate assembly). The processible composites based electrochemical capacitors using 0.5 M NaClO4‐Acetonitril electrolyte showed super capacitance with ease in fabrication and cost effectiveness in comparison to other similar materials based capacitors. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation and characterization of isotropic polyurethane magnetorheological elastomer through in situ polymerization
Authors: Wu Jinkui , Gong Xinglong , Chen Lin , Xia Hesheng , Hu Zaiguo
Published: June 2009

The highly filled isotropic polyurethane (PU) elastomer with a magnetorheological (MR) effect was prepared through an in situ polycondensation method. The carbonyl iron particles were treated by coupling agents and then the dispersions of polyol/carbonyl iron particles was prepared by a ball milling process. The dispersion problem of magnetizable particles at a high content in PU matrix was tried to overcome by the combination of surface modification, ball milling, and in situ polymerization. The microstructure and properties of the composite were examined in detail. With increasing the content of carbonyl iron particles, the degree of phase separation of PU increased and the glass transition temperature (Tg) of PU soft segment decreased. Highly filled carbonyl iron particles led to the decrease in the thermal stability of PU matrix, especially in the heating air atmosphere. The MR effect appeared when the content of carbonyl iron particles was higher than 50 wt %, and became relatively pronounced at a 70 wt % of carbonyl iron content. The mechanical properties of PU MR elastomers were deteriorated significantly at a high content of carbonyl iron. Surface modification of carbonyl iron particles can improve the mechanical properties to some extent; however, it was also found that surface modification led to a decrease in the MR effect because of the improved interfacial adhesion. The MR test showed that the maximum absolute MR effect and relative MR effect of PU composite were ∼ 0.31 MPa and ∼ 8.1% at 1 Hz and 400 mT with 70 wt % of carbonyl iron, respectively. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Influence of the incorporation of fine calcium carbonate particles on the impact strength of polypropylene/polystyrene‐block‐poly(ethylene butene)‐block‐polystyrene blends
Authors: Hikasa Shigeki , Nagata Kazuya , Miyahara Kenji , Izumi Toshihiro , Suda Toshiya , Toyohara Asami , Kato Atushi , Nakamura Yoshinobu
Published: June 2009

The Izod impact strength of two kinds of ternary composites was investigated. One consisted of polypropylene (PP), the triblock copolymer polystyrene‐block‐poly(ethylene butene)‐block‐polystyrene (SEBS), and calcium carbonate (CaCO3) particles, and the other consisted of PP, carboxylated SEBS (C‐SEBS), and CaCO3 particles. The mean size of the CaCO3 particles was about 160 nm. According to scanning electron microscopy observations, the composite with SEBS showed a morphology in which SEBS domains and CaCO3 particles were independently dispersed in the PP matrix. On the other hand, the composite with C‐SEBS showed a morphology in which CaCO3 particles were encapsulated by C‐SEBS; that is, a core–shell structure was formed. The Izod impact strength of the composite with SEBS was higher than that of the composite with C‐SEBS and the PP/SEBS and PP/C‐SEBS binary blends. According to observations of the fractured surface, the stress‐whitened area was larger in the composite with SEBS than in the composite with C‐SEBS and the PP/SEBS and PP/C‐SEBS binary blends. The toughening mechanism of the composite, using nanometer‐sized CaCO3 particles in combination with SEBS, was examined. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Strain effect on recovery behaviors from circular deformation of natural rubber vulcanizate
Authors: Choi Sung‐Seen , Han Dong‐Hun
Published: June 2009

The recovery behaviors of vulcanized natural rubber from circular deformation were studied by varying sample length to investigate the influence of the degree of applied strain to the sample. The stress and strain varied uniformly across the thickness of the sample, and the degree of applied stress and strain to the sample decreased with increasing the sample length. The linear sample was made into a circular form and thermally aged in a convection oven. The recovery was measured after removing from the circular deformation. The recovery increased by decreasing the sample length. The difference in recoveries of the samples with different lengths reduced at high temperature. The short sample had higher heat‐resisting property for recovery than the long sample. The experimental results were explained by the rearrangement and stabilization of the deformed rubber chains as well as the crosslink density change. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Effect of surface esterification with octenyl succinic anhydride on hydrophilicity of corn starch films
Authors: Zhou Jiang , Ren Lili , Tong Jin , Ma Yunhai
Published: June 2009

Surface of corn starch films was modified through esterification using octenyl succinic anhydride as reactant. Physical properties of the films, moisture absorption, and water contact angle were measured to characterize the effect of the surface esterification modification. The influences of the concentration of alkaline aqueous solution for activating starch, reaction temperature, and time were investigated. It was found that the pretreatments with 1.0% or 2.0% NaOH aqueous solution and reacting at 35°C for 6 h gave rise to films possessing higher water contact angle, lower equilibrium moisture content, and moisture absorption rate at 95% relative humidity (RH). After the surface esterification modification, the equilibrium moisture content of the starch film decreased up to 29% at 95% RH and the surface water contact angle of the film increased up to 83%. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis and Anti‐Inflammatory Activity of Novel (4‐Hydroxyphenyl)(2,4‐dimethoxyphenyl) Methanone Derivatives
Authors: Vinaya Kambappa , Naika Raja , Kumar Channappillekoppal S. Ananda , Ranganath Somasagara R. , Prasad Salekoppal B. Benaka , Krishna Venkatarangaiah , Rangappa Kanchugarakoppal S.
Published: June 2009

In the scope of the research program aiming to perform the synthesis and pharmacological evaluation of novel possible anti‐inflammatory compounds, in this manuscript, we report the synthesis of novel carboxamide 9a‐d and thioamide 10a‐d derivatives from the benzophenone and piperidine nucleus. Variation in the functional group at the N‐terminal of piperidine led to two sets of compounds, bearing the carboxamide and thioamide, respectively. The characterization of this new class of compounds was performed with 1H‐NMR, LC‐MS, IR, and elemental analysis. The newly synthesized compounds were screened for their anti‐inflammatory activity by carrageenan‐induced foot pad oedema assay and were compared with a standard drug. All the compounds exhibited anti‐inflammatory activity at the dose of 30 mg/kg p.o. with varying degree from 52 to 67% inhibition of oedema. The compounds 9d and 10d with dichloro and fluoro substitution showed more potent activity at 30 mg/kg p.o. than the standard drug.
Gene regulatory networks in embryonic stem cells and brain development
Authors: Ghosh Dhimankrishna , Yan Xiaowei , Tian Qiang
Published: June 2009

Embryonic stem cells (ESCs) are endowed with the ability to generate multiple cell lineages and carry great therapeutic potentials in regenerative medicine. Future application of ESCs in human health and diseases will embark on the delineation of molecular mechanisms that define the biology of ESCs. Here, we discuss how the finite ESC components mediate the intriguing task of brain development and exhibit biomedical potentials to cure diverse neurological disorders. Birth Defects Research (Part C) 87:182–191, 2009. © 2009 Wiley‐Liss, Inc.
Dynamical approaches to modeling developmental gene regulatory networks
Authors: Geard Nicholas , Willadsen Kai
Published: June 2009

The network of interacting regulatory signals within a cell comprises one of the most complex and powerful computational systems in biology. Gene regulatory networks (GRNs) play a key role in transforming the information encoded in a genome into morphological form. To achieve this feat, GRNs must respond to and integrate environmental signals with their internal dynamics in a robust and coordinated fashion. The highly dynamic nature of this process lends itself to interpretation and analysis in the language of dynamical models. Modeling provides a means of systematically untangling the complicated structure of GRNs, a framework within which to simulate the behavior of reconstructed systems and, in some cases, suites of analytic tools for exploring that behavior and its implications. This review provides a general background to the idea of treating a regulatory network as a dynamical system, and describes a variety of different approaches that have been taken to the dynamical modeling of GRNs. Birth Defects Research (Part C) 87:131–142, 2009. © 2009 Wiley‐Liss, Inc.
A review on data mining and continuous optimization applications in computational biology and medicine
Authors: Weber Gerhard‐Wilhelm , Özöğür‐Akyüz Süreyya , Kropat Erik
Published: June 2009

An emerging research area in computational biology and biotechnology is devoted to mathematical modeling and prediction of gene‐expression patterns; it nowadays requests mathematics to deeply understand its foundations. This article surveys data mining and machine learning methods for an analysis of complex systems in computational biology. It mathematically deepens recent advances in modeling and prediction by rigorously introducing the environment and aspects of errors and uncertainty into the genetic context within the framework of matrix and interval arithmetics. Given the data from DNA microarray experiments and environmental measurements, we extract nonlinear ordinary differential equations which contain parameters that are to be determined. This is done by a generalized Chebychev approximation and generalized semi‐infinite optimization. Then, time‐discretized dynamical systems are studied. By a combinatorial algorithm which constructs and follows polyhedra sequences, the region of parametric stability is detected. In addition, we analyze the topological landscape of gene‐environment networks in terms of structural stability. As a second strategy, we will review recent model selection and kernel learning methods for binary classification which can be used to classify microarray data for cancerous cells or for discrimination of other kind of diseases. This review is practically motivated and theoretically elaborated; it is devoted to a contribution to better health care, progress in medicine, a better education, and more healthy living conditions. Birth Defects Research (Part C) 87:165–181, 2009. © 2009 Wiley‐Liss, Inc.
An electron‐flow model can predict complex redox reactions in mixed‐culture fermentative BioH2: Microbial ecology evidence
Authors: Lee Hyung‐Sool , Krajmalinik‐Brown Rosa , Zhang Husen , Rittmann Bruce E.
Published: June 2009

We developed the first model for predicting community structure in mixed‐culture fermentative biohydrogen production using electron flows and NADH2 balances. A key assumption of the model is that H2 is produced only via the pyruvate decarboxylation‐ferredoxin‐hydrogenase pathway, which is commonly the case for fermentation by Clostridium and Ethanoligenens species. We experimentally tested the model using clone libraries to gauge community structures with mixed cultures in which we did not pre‐select for specific bacterial groups, such as spore‐formers. For experiments having final pHs 3.5 and 4.0, where H2 yield and soluble end‐product distribution were distinctly different, we established stoichiometric reactions for each condition by using experimentally determined electron equivalent balances. The error in electron balancing was only 3% at final pH 3.5, in which butyrate and acetate were dominant organic products and the H2 yield was 2.1 mol H2/mol glucose. Clone‐library analysis showed that clones affiliated with Clostridium sp. BL‐22 and Clostridium sp. HPB‐16 were dominant at final pH 3.5. For final pH 4.0, the H2 yield was 0.9 mol H2/mol glucose, ethanol, and acetate were the dominant organic products, and the electron balance error was 13%. The significant error indicates that a second pathway for H2 generation was active. The most abundant clones were affiliated with Klebsiella pneumoniae, which uses the formate‐cleavage pathway for H2 production. Thus, the clone‐library analyses confirmed that the model predictions for when the pyruvate decarboxylation‐ferredoxin‐hydrogenase pathway was (final pH 3.5) or was not (final pH 4.0) dominant. With the electron‐flow model, we can easily assess the main mechanisms for H2 formation and the dominant H2‐producing bacteria in mixed‐culture fermentative bioH2. Biotechnol. Bioeng. 2009; 104: 687–697 © 2009 Wiley Periodicals, Inc.
A comprehensive model of simultaneous denitrification and methanogenic fermentation processes
Authors: Tugtas A. Evren , Tezel U. , Pavlostathis Spyros G.
Published: June 2009

The denitrification process was incorporated into the IWA Anaerobic Digestion Model No. 1 (ADM1) in order to account for the effect of denitrification on the methanogenic fermentation process. The model was calibrated and optimized using previously published experimental data and kinetic parameter values obtained with a mixed, mesophilic (35°C) methanogenic culture. Model simulations were used to predict the effect of nitrate reduction on the methanogenic fermentation process in batch, semi‐continuous, and continuous flow reactors experiencing operational changes and/or system disturbances. The extended model clearly revealed the importance of substrate competition between denitrifiers and non‐denitrifiers as well as the impact of N‐oxide inhibition on process interactions between fermentation, methanogenesis, and denitrification. Biotechnol. Bioeng. 2010;105: 98–108. © 2009 Wiley Periodicals, Inc.
Manipulation of microparticles for construction of array patterns by negative dielectrophoresis using multilayered array and grid electrodes
Authors: Ino Kosuke , Shiku Hitoshi , Ozawa Fumisato , Yasukawa Tomoyuki , Matsue Tomokazu
Published: June 2009

In this study, a useful method was developed to fabricate array patterns of microparticles not on electrode surfaces, but on arbitrary surfaces, using negative‐dielectrophoresis (n‐DEP). First, electrodes were designed and electric field simulations were performed to manipulate microparticles toward target areas. Based on the simulation results, multilayered array and grid (MLAG) electrodes, consisting of array electrodes surrounded by insulated regions and a grid electrode, were fabricated for the formation of localized, non‐uniform electric fields. The MLAG electrode was mounted to a target substrate in a face‐to‐face configuration with a spacer. When an AC voltage (4.60 Vrmsand 1 MHz) was applied to the MLAG electrode, array patterns of 6 and 20 µm diameter microparticles were rapidly fabricated on the target substrate with ease. The results suggest that MLAG electrodes can be widely applied for the fabrication of biochips including cell arrays. Biotechnol. Bioeng. 2009; 104: 709–718 © 2009 Wiley Periodicals, Inc.
The chromatography‐free release, isolation and purification of recombinant peptide for fibril self‐assembly
Authors: Hartmann B.M. , Kaar W. , Yoo I.K. , Lua L.H.L. , Falconer R.J. , Middelberg A.P.J.
Published: June 2009

One of the major expenses associated with recombinant peptide production is the use of chromatography in the isolation and purification stages of a bioprocess. Here we report a chromatography‐free isolation and purification process for recombinant peptide expressed in Escherichia coli (E. coli). Initial peptide release is by homogenization and then by enzymatic cleavage of the peptide‐containing fusion protein, directly in the E. coli homogenate. Release is followed by selective solvent precipitation (SSP) to isolate and purify the peptide away from larger cell contaminants. Specifically, we expressed in E. coli the self‐assembling β‐sheet forming peptide P11‐2 in fusion to thioredoxin. Homogenate was heat treated (55°C, 15 min) and then incubated with tobacco etch virus protease (TEVp) to release P11‐2 having a native N‐terminus. SSP with ethanol at room temperature then removed contaminating proteins in an integrated isolation‐purification step; it proved necessary to add 250 mM NaCl to homogenate to prevent P11‐2 from partitioning to the precipitate. This process structure gave recombinant P11‐2 peptide at 97% polypeptide purity and 40% overall yield, without a single chromatography step. Following buffer‐exchange of the 97% pure product by bind‐elute chromatography into defined chemical conditions, the resulting peptide was shown to be functionally active and able to form self‐assembled fibrils. To the best of our knowledge, this manuscript reports the first published process for chromatography‐free recombinant peptide release, isolation and purification. The process proved able to deliver functional recombinant peptide at high purity and potentially low cost, opening cost‐sensitive materials applications for peptide‐based materials. Biotechnol. Bioeng. 2009; 104: 973–985. © 2009 Wiley Periodicals, Inc.
Rapid optimization of protein freeze‐drying formulations using ultra scale‐down and factorial design of experiment in microplates
Authors: Grant Yitzchak , Matejtschuk Paul , Dalby Paul A.
Published: June 2009

Retaining biopharmaceutical proteins in a stable form is critical to their safety and efficacy, and is a major factor for optimizing the final product. Freeze‐dried formulations offer one route for improved stability. Currently the optimization of formulations for freeze‐drying is an empirical process that requires many time‐consuming experiments and also uses large quantities of product material. Here we describe a generic framework for the rapid identification and optimization of formulation excipients to prevent loss of protein activity during a lyophilization process. Using factorial design of experiment (DOE) methods combined with lyophilization in microplates a range of optimum formulations were rapidly identified that stabilized lactose dehydrogenase (derived from Lactobacillus leichmanii) during freeze‐drying. The procedure outlined herein involves two rounds of factorially designed experiments—an initial screen to identify key excipients and potential interactions followed by a central composite face designed optimization experiment. Polyethylene glycol (PEG) and lactose were shown to have significant effects on maintaining protein stability at the screening stage and optimization resulted in an accurate model that was used to plot a window of operation. The variation of freezing temperatures and rates of sublimation that occur across a microplate during freeze‐drying have been characterized also. The optimum formulation was then freeze‐dried in stoppered vials to verify that the microscale data was relevant to the effects observed at larger pilot scales. This work provides a generic approach to biopharmaceutical formulation screening where possible excipients can be screened for single and interactive effects thereby increasing throughput while reducing costs in terms of time and materials. Biotechnol. Bioeng. 2009; 104: 957–964. © 2009 Wiley Periodicals, Inc.
Generation and validation of a revised classification for oesophageal and junctional adenocarcinoma
Authors: Peters C J , Hardwick R H , Vowler S L , Fitzgerald R C
Published: June 2009

Background

Oesophageal adenocarcinoma is the commonest oesophageal malignancy in the West, but is staged using a system designed for squamous cell carcinoma. The aim was to develop and validate a staging system for oesophageal and junctional adenocarcinoma.

Methods

Patients with oesophageal adenocarcinoma (Siewert types I and II) undergoing oesophagectomy with curative intent were randomly assigned to generation (313 patients) and validation (131) data sets. Outcome in the generation data set was associated with histopathological features; a revised node (N) classification was derived using recursive partitioning and tested on the validation data set.

Results

A revised N classification based on number of involved lymph nodes (N0, none; N1, one to five; N2, six or more) was prognostically significant (P < 0·001). Patients with involved nodes on both sides of the diaphragm, regardless of number, had the same outcome as the N2 group. When applied to the validation data set, the revised classification (including nodal number and location) provided greater discrimination between node-positive patients than the existing system (P < 0·001).

Conclusion

A revised N classification based on number and location of involved lymph nodes provides improved prognostic power and incorporates features that may be useful before surgery in clinical management decisions.
Influence of nephron mass and a phosphorylated 38 mitogen-activated protein kinase inhibitor on the development of early and long-term injury after renal warm ischaemia
Authors: Jayle C , Faure J P , Thuillier R , Goujon J M , Richer J P , Hauet T
Published: June 2009

Background

Renal ischaemia is accompanied by acute and chronic complications. Tumour necrosis factor (TNF) α production via p38 mitogen-activated protein kinase (MAPK) is one of the pivotal mechanisms linking ischaemia to inflammation and could be a therapeutic target. FR167653 (FR), an inhibitor of p38 MAPK and TNF-α production, may ameliorate renal damage through its effects on TNF-α.

Methods

Warm ischaemia (WI) was induced in male pigs by bilateral clamping of the renal pedicle for 60 min or unilateral renal clamping after contralateral nephrectomy. FR was administered before and during WI, and continuously for 3 h during reperfusion in pigs exposed to the same WI conditions. Experimental groups were compared with sham-operated pigs and those subjected to unilateral nephrectomy without renal ischaemia. Renal function, fibrosis and inflammation were evaluated, and expression of monocyte chemoattractant protein 1, transforming growth factor β and TNF-α was determined after 12 weeks.

Results

FR significantly reduced renal failure in groups subjected to unilateral nephrectomy and bilateral renal ischaemia. Proteinuria was significantly reduced, and inflammation and expression of proinjury proteins were diminished, accompanied by a reduction in renal fibrosis.

Conclusion

Control of TNF-α production and activity prevents renal damage after prolonged WI.
Relationship between 31P metabolites and oncolytic viral therapy sensitivity in human colorectal cancer xenografts
Authors: Silberhumer G R , Zakian K , Malhotra S , Brader P , Gönen M , Koutcher J , Fong Y
Published: June 2009

Background

Studies using phosphorus magnetic resonance spectroscopy (MRS) have pointed to the significance of phospholipid metabolite alterations as biochemical markers for tumour progression or therapy response.

Methods

Spectroscopic imaging was performed in colorectal flank tumours in nude mice. In vivo tumour doubling times for each cell line were measured. In vivo sensitivity of each tumour line to treatment with G207 and NV1020 oncolytic viruses was assessed. Correlations between viral sensitivity and tumour doubling time and phosphorus MRS were estimated.

Results

For G207 virus, in vitro cytotoxicity tests showed cell viability at multiplicities of infection (ratio of viral particles per tumour cell) of 0·1 on day 6 as follows: C85, less than 1 per cent; HCT8, 1 per cent; LS174T, 9 per cent; HT29, 18 per cent; and C18, 92 per cent. Respective values for NV1020 were 1, 18, 4, 18 and 86 per cent. The phosphoethanolamine to phosphocholine ratio was significantly lower in virus-sensitive than -insensitive cells, and was dependent on tumour doubling time.

Conclusion

Alterations in membrane phospholipid metabolites that relate to proliferation of cancer cells affect the efficacy of oncolytic viral therapy. MRS proved a highly sensitive non-invasive tool for predicting the efficacy of viruses.
Liberal selection criteria for liver transplantation for hepatocellular carcinoma
Authors: Muscari F , Foppa B , Kamar N , Peron J M , Selves J , Suc B
Published: June 2009

Background

To help increase the number of transplants available for hepatocellular carcinoma in cirrhotic livers, this single-centre retrospective study compared the safety and feasibility of new, more liberal, selection criteria—no more than five tumours, with the largest tumour no greater than 5 cm (5/5 criteria)—with classical criteria.

Methods

Data from operations performed in 1990–2005 were extracted from preoperative radiological findings and postoperative specimen analyses, and four groups were constructed: Paul Brousse, Milan, University of California, San Francisco (UCSF) and 5/5 criteria. A fifth group comprised patients whose tumour load exceeded the 5/5 criteria. Survival and recurrence rates were compared.

Results

For the 110 patients in the study, survival rates (overall and disease-free) were 72·8 and 66·8 per cent at 5 and 10 years respectively, with a 5·5 per cent recurrence rate. The 5-year survival rate was 65, 77, 68 and 77 per cent for Paul Brousse, Milan, UCSF and 5/5 preoperative radiological criteria, with recurrence rates of 4, 4, 3 and 3 per cent, respectively. On multivariable analysis, the only factor that influenced survival was tumour load in excess of the 5/5 criteria.

Conclusion

Use of the more liberal 5/5 criteria for selecting patients for liver transplantation results in similar disease-free and overall survival rates to classical criteria.
Prognostic significance of peritoneal tumour cells identified at surgery for colorectal cancer
Authors: Katoh H , Yamashita K , Sato T , Ozawa H , Nakamura T , Watanabe M
Published: June 2009

Background

The prognostic significance of intraperitoneal tumour cells (IPCs) in colorectal cancer is not clear. This study aimed to determine whether detection of IPCs could be used a prognostic marker for selecting patients at high risk of recurrence.

Methods

The study included 226 patients with colorectal cancer who underwent elective resection. Clinical variables, including the presence of IPCs, were analysed for their prognostic significance.

Results

Thirty-three patients (14·6 per cent) were positive for IPCs. Univariable analysis indicated that the presence of IPCs was a significant prognostic factor in patients with stage III colorectal cancer; the 5-year disease-specific survival rate was 14 per cent in IPC-positive patients versus 79 per cent in those without IPCs (P < 0·001). Multivariable analysis showed that IPC positivity was the most robust prognostic factor in stage III disease (hazard ratio 2·2; P = 0·003), whereas nodal category (N1 or N2) showed no significant association with prognosis. In addition, IPCs were associated with haematogenous recurrence (P = 0·004) rather than peritoneal or local recurrence (P = 0·077) in patients with stage III disease.

Conclusion

The presence of IPCs is a significant prognostic factor in patients with stage III colorectal cancer.
MicroRNAs are novel biomarkers of colorectal cancer
Authors: Aslam M I , Taylor K , Pringle J H , Jameson J S
Published: June 2009

Background

Recent studies have identified unique small ribonucleic acids called microRNAs (miRNAs) in colonic tumour tissue and blood that may accurately diagnose the presence of colorectal cancer and help predict disease recurrence. This review explores the potential role of these biomarkers.

Methods

A literature search identified studies describing miRNAs in colorectal cancers. The outcomes of interest included diagnosis, progression and recurrence of disease, and future therapy.

Results

Overexpression and silencing of specific miRNAs are associated with the development and progression of colorectal cancer. Such a role in oncogenesis suggest that miRNAs may be important targets for gene therapies. Differential expression of specific miRNAs in tissues and blood offers the prospect of their use in early detection and screening for colorectal cancer. MiRNAs are implicated in metastasis and cytotoxic drug resistance. Their manipulation has potential in both prevention of recurrence and palliation.

Conclusion

The miRNAs expression profile in tissue and blood has potential for their use in the detection, screening and surveillance of colorectal cancer. Furthermore, miRNAs may be targeted by gene therapy to treat colorectal cancer.
Conservative management of symptomatic spontaneous isolated dissection of the superior mesenteric artery
Authors: Cho Y P , Ko G Y , Kim H K , Moon K M , Kwon T W
Published: June 2009

Background

Spontaneous isolated dissection of the superior mesenteric artery (SMA) is uncommon. Because of its rarity, the risk factors, aetiology and natural history are unclear, and there is no consensus on the optimal treatment strategy.

Methods

Seven consecutive patients with symptomatic spontaneous isolated SMA dissection who received conservative treatment between March 2003 and February 2008 were included in this study. Their clinical characteristics, treatment methods and outcomes were analysed retrospectively.

Results

Acute abdominal pain was the most common clinical manifestation. Initial contrast-enhanced dynamic computed tomography (CT) showed isolated SMA dissection with partial thrombosis in all seven patients. Full anticoagulation was carried out immediately after the diagnosis. Clinical symptoms disappeared within 14 days and follow-up CT showed complete resolution of the dissection in four patients. After a mean follow-up of 23 months, there was no mortality or morbidity related to the dissection.

Conclusion

In patients with symptomatic spontaneous isolated dissection of the SMA, conservative management is feasible if there is no evidence of bowel infarction or bleeding.
Blumgart anastomosis for pancreaticojejunostomy minimizes severe complications after pancreatic head resection
Authors: Kleespies A , Rentsch M , Seeliger H , Albertsmeier M , Jauch K-W , Bruns C J
Published: June 2009

Background

Leakage from the pancreaticojejunostomy is the major cause of septic complications after partial pancreaticoduodenectomy. This study evaluated a new transpancreatic ∪-suture technique (Blumgart anastomosis, BA), which aims to avoid shear forces during knot-tying.

Methods

Using a before–after study design, BA was compared with a modified Cattell–Warren anastomosis (CWA). Two patient cohorts (CWA, 90; BA, 92), which were similar with respect to primary diagnosis, age, sex and American Society of Anesthesiologists score, were compared retrospectively. Dependent variables were surgical and overall morbidity and mortality after partial pancreaticoduodenectomy.

Results

Duration of operation (354 versus 328 min for CWA versus BA; P = 0·002), pancreatic leakage rate (13 versus 4 per cent; P = 0·032), postoperative haemorrhage (11 versus 3 per cent; P = 0·040), total surgical complications (31 versus 15 per cent; P = 0·011), general complications (36 versus 17 per cent; P = 0·005) and length of intensive care unit stay (median 5·4 versus 2·8 days; P = 0·015) were significantly reduced after BA. These effects were not related merely to an improvement over time.

Conclusion

BA appears to be a fast, simple and safe technique for pancreaticojejunostomy. It might reduce leakage rates and surgical complications after partial pancreaticoduodenectomy.
Leucocyte depletion of perioperative blood transfusion does not affect long-term survival and recurrence in patients with gastrointestinal cancer
Authors: Lange M M , van Hilten J A , van de Watering L M G , Bijnen B A , Roumen R M H , Putter H , Brand A , van de Velde C J H
Published: June 2009

Background

Perioperative red blood cell (RBC) transfusion may be associated with a poor prognosis in cancer surgery. Allogeneic leucocytes are assumed to play a causal role. This study evaluated the long-term effect of transfusion with leucocyte-depleted (LD) blood in patients with gastrointestinal cancer.

Methods

The Transfusion Associated Complications = Transfusion Induced Complications? (TACTIC) study is a multicentre randomized controlled trial evaluating the short-term benefits of LD versus non-LD RBC transfusions. The present study evaluated 5-year survival and cancer recurrence among 512 patients with gastrointestinal cancer included in the TACTIC study.

Results

Some 89·2 per cent of patients had a primary tumour and 79·7 per cent underwent surgery with curative intent; 243 patients received perioperative RBC transfusion (median 3 units). The 5-year overall survival rate of patients with any type of gastrointestinal cancer was 50·8 per cent in the LD group and 45·8 per cent in the non-LD group (P = 0·191). Corresponding 5-year disease-free survival rates were 60·0 and 56·6 per cent (P = 0·482), and recurrence rates 32·9 and 34·3 per cent (P = 0·864).

Conclusion

Leucocyte depletion is not associated with better long-term survival and lower recurrence rates in patients with gastrointestinal cancer.
Improving the efficacy of sacral nerve stimulation for faecal incontinence by alteration of stimulation parameters
Authors: Dudding T C , Vaizey C J , Gibbs A , Kamm M A
Published: June 2009

Background

Sacral nerve stimulation (SNS) is an effective treatment for faecal incontinence, but only standard stimulation parameters have been used. This study assessed the clinical impact of altering the parameters.

Methods

Twelve patients with partially improved faecal incontinence following SNS underwent acute testing to select optimal stimulation parameters; rectal compliance was used as a surrogate marker. Parameters tested were: stimulation off; frequency 14 (standard), 31 or 6·9 Hz; and pulse duration 210 (standard), 450 or 90 µs. Patients completed a 2-week bowel diary, St Mark's continence score (SMCS) and Rockwood faecal incontinence quality-of-life (FIQL) score before testing using standard settings, and after testing using optimized settings.

Results

Optimal settings, determined by greatest increase in rectal compliance, were shorter pulse width in five patients and higher frequency in seven. Optimized stimulation resulted in a decrease in mean episodes of incontinence from 2·3 to 1·2 per week (P = 0·031), soiling from 3·3 to 1·7 days per week (P = 0·016), faecal urgency from 31 to 18 per cent of all evacuations (P = 0·055) and SMCS from 12·3 to 8·7 (P = 0·008); the FIQL coping/behaviour score improved (P = 0·008).

Conclusion

With a shorter pulse width and higher frequency, clinical efficacy in patients undergoing SNS for faecal incontinence can be improved.
Epidemiology of major trauma
Authors: Søreide K
Published: June 2009

First article of ‘Trauma Series’
Risk of tumour progression in early-stage hepatocellular carcinoma after radiofrequency ablation
Authors: Fernandes M L , Lin C-C , Lin C-J , Chen W-T , Lin S-M
Published: June 2009

Background

This study aimed objectively to quantify the risk of tumour progression beyond the Milan criteria following radiofrequency (RF) ablation for hepatocellular carcinoma (HCC) and to identify factors associated with tumour progression.

Methods

Some 111 patients (136 tumours) with liver cirrhosis undergoing RF ablation for HCC within Milan criteria between February 2004 and June 2007 were enrolled in the study. Data were analysed retrospectively from a prospectively collected database.

Results

The cumulative probability of tumour progression beyond the Milan criteria at 6, 12, 18, 24 and 36 months of RF ablation was 6·4, 11·0, 16·1, 21·2 and 44·8 per cent respectively. On multivariable analysis, factors independently associated with tumour progression were failure to achieve primary technique effectiveness (P = 0·005), α-fetoprotein level above 200 ng/ml (P = 0·013) and Child–Pugh grade B cirrhosis (P = 0·034). Failure to achieve primary RF ablation technique effectiveness was associated with tumour location in segment VIII (P = 0·033), a cool-down temperature of 70 °C or less (P = 0·043) and multiple overlapping ablations (P = 0·029).

Conclusion

This study provides clinicians with an objective risk of tumour progression beyond the Milan criteria after RF ablation at multiple time points. Primary technique failure is identified as a risk factor for tumour progression.
Reoperative surgery for primary hyperparathyroidism
Authors: Bartsch D K , Rothmund M
Published: June 2009

Successful in up to 90 per cent of patients
Treatment of liver metastases from neuroendocrine tumours in relation to the extent of hepatic disease (Br J Surg 2009; 96: 175–184)
Authors: Søreide J A
Published: June 2009

The Editors welcome topical correspondence from readers relating to articles published in the Journal. Responses should be sent electronically via the BJS website (www.bjs.co.uk). All letters will be reviewed and, if approved, appear on the website. A selection of these will be edited and published in the Journal. Letters must be no more than 250 words in length.
Balloon mitral valvotomy in patients with mitral stenosis and left atrial thrombus
Authors: Manjunath C.N. , Srinivasa K.H. , Ravindranath K.S. , Manohar J.S. , Prabhavathi B. , Dattatreya P.V. , Sridhar L. , Dhanalakshmi C.
Published: June 2009

Objectives:

To evaluate the safety and efficacy of balloon mitral valvotomy (BMV) in symptomatic rheumatic mitral stenosis (MS) patients with left atrial (LA) thrombus and to address the technical issues.

Background:

LA thrombus in patients with MS has long been regarded as a contraindication for BMV. There are few reports of BMV in presence of LA appendage (LAA) thrombus and reports of BMV in presence of LA body thrombus are still rare.

Methods:

2,763 patients with suitable valve morphology were screened for BMV. 194 patients had LA/LAA thrombus and were put on adequate anticoagulation for 8–12 weeks. A total of 108 patients with persistent LA thrombus who satisfied the inclusion criteria (LA thrombus type Ia, Ib, and IIa) formed the study group and the remaining 2,622 patients who did not have any LA thrombus constituted the control group. All patients in the study group underwent BMV by modified over the wire technique.

Results:

There was significant and comparable improvement in the mitral valve area, mitral valve gradient, LA mean and pulmonary artery systolic pressure following the procedure in both groups. In the study group, there were no thromboembolic episodes during the procedure. However, there was one case of transient ischemic attack in the study group which occurred 6 hr after a successful BMV. In the study group, one patient had cardiac tamponade needing aspiration and there was no in‐hospital death.

Conclusions:

In selected patients of mitral stenosis with LA thrombus (type Ia, Ib, and IIa), BMV can be performed safely with the modified over the wire technique. Systemic thromboembolism, technical failures and other complications are very rare when performed by experienced operators.  © 2009 Wiley‐Liss, Inc.