bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis and solubility properties of chitin acetate/butyrate copolymers
Authors: Draczynski Zbigniew 
Published: April 2011

AbstractIn this article, syntheses of chitin acetate/butyrate copolymers with different contents of acetyl residue in polymer chain have been described. Chitin copolymers as well as pure diacetylchitin (DAC) and dibutyrylchitin (DBC) have been obtained in the reaction of shrimp chitin with mixture of acetic and butyric anhydrides used in different proportion. Reactions have been carried out under heterogeneous condition with perchloric acid (PA) used as a catalyst of reaction. Chemical structure of DAC, DBC, and co‐(acetate/butyrates) was confirmed in 1H‐NMR as well as in Fourier transform infrared (FTIR) investigations. Results of 1H‐NMR investigation showed that in all cases of chitin esterification carried out at applied conditions, final products with summary degree of substitution (DP) closed to 2 have been obtained. Prepared chitin acetate/butyrate copolymers with high degree of polymerization (DP) (based on value of intrinsic viscosity) with varying amount of acetyl groups from 0.24 to 1.29 have been formed depending on the mixture composition of acetic and butyric acid anhydrides. All obtained co‐(acetate/butyrates) are soluble in organic solvents such as dimethylformamide (DMF), dimethylsulfoxide (DMSO), dimethylacetamide (DMAc) as well as ethanol and form strong transparent films. It was stated that solubility of obtained chitin copolyesters slightly decreases with increase of the acetyl groups content in polymer chain, but it is still high enough to be taken into consideration for eventual production of fibers or scaffolds. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Photogeneration of gelatinous networks from pre‐existing polymers
Authors: Carroll Gregory T. , Devon Triplett L. , Moscatelli Alberto , Koberstein Jeffrey T. , Turro Nicholas J. 
Published: April 2011

AbstractIn this manuscript we report the crosslinking of pre‐existing macromolecules in solution through the use of photoactive benzophenone chromophores. We show that a bifunctional crosslinker composed of two benzophenone chromophores as well as a single benzophenone chromophore crosslink poly (butadiene) and poly (ethylene oxide) in solution to form insoluble gels when irradiated with UV light. The molecular weight between crosslinks of the photogenerated gels was compared for the two crosslinkers, for an equivalent amount of benzophenone chromophores in each solution, by measuring the swelling ratio of the gels formed. Gels formed from the bifunctional benzophenone crosslinker were shown to contain more than twice as many crosslinks compared to gels formed from the crosslinker composed of a single benzophenone chromophore. EPR measurements of a nitroxide derivative absorbed into the gels further supported a higher crosslink density for the gels formed from the bifunctional benzophenone crosslinker. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and swelling characteristics of responsive carboxybetaine gel
Authors: Tarannum Nazia , Singh Meenakshi 
Published: April 2011

AbstractA polyimminium gel, Dimedone‐[N, N′ melaminium] butyrocarboxylate copolymer, comprising of zwitterionic carboxybetaine repeat units was synthesized via a catalyst free facile polycondensation approach. The polymer was studied for its photoluminescence, thermal, and swelling behavior. Swelling behavior was investigated in different solvent mixtures as well as in pure solvents. The extent of swelling was dictated by solvent composition, such as dielectric constant, pH, ionic strength, and other variables for instance, temperature and crosslinking density. Gel was soluble in alkali and could be regenerated on treatment with an acid. This pH responsive behavior could find various industrial applications, especially in wastewater treatment. A preliminary study on sorption of dyes was also carried out. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Anti‐C1q antibodies are associated with systemic lupus erythematosus global activity but not specifically with nephritis: A controlled study of 126 consecutive patients
Authors: Katsumata Yasuhiro , Miyake Kohei , Kawaguchi Yasushi , Okamoto Yuko , Kawamoto Manabu , Gono Takahisa , Baba Sayumi , Hara Masako , Yamanaka Hisashi 
Published: April 2011

AbstractObjectiveSeveral studies have shown that anti‐C1q antibodies correlate with the occurrence and activity of nephritis in systemic lupus erythematosus (SLE). However, the significance of anti‐C1q antibodies in SLE has not been fully characterized. The aim of this study was to investigate associations between anti‐C1q antibodies and clinical and serologic parameters of SLE.MethodsAn enzyme‐linked immunosorbent assay kit was used to measure anti‐C1q antibodies in the sera of 126 consecutive patients with active SLE who were admitted to our university hospital from 2007 through 2009. Sera obtained from patients with high titers of anti‐C1q antibodies at the initial evaluation (n = 20) were reevaluated following treatment. Control sera were obtained from patients with other autoimmune diseases and from normal healthy control subjects (n = 20 in each group). Associations between anti‐C1q antibodies and clinical and serologic parameters of SLE were statistically analyzed.ResultsAnti‐C1q antibodies were detected in the sera of 79 of 126 patients with SLE. The prevalence and titers of anti‐C1q antibodies were significantly (P < 0.0001) higher in SLE patients than in patients with rheumatoid arthritis, patients with systemic sclerosis, and normal healthy control subjects. The prevalence and titers of anti‐C1q antibodies were not significantly associated with active lupus nephritis (P = 0.462 and P = 0.366, respectively). Anti‐C1q antibody titers were significantly correlated with SLE Disease Activity Index 2000 scores and the levels of anti–double‐stranded DNA antibodies, C3, C4, CH50, and C1q (P < 0.0001 for all comparisons). Moreover, anti‐C1q antibody titers significantly decreased as clinical disease was ameliorated following treatment (P = 0.00097).ConclusionThese findings indicate that anti‐C1q antibodies are associated with SLE global activity but not specifically with active lupus nephritis.
Association of autoantibodies to heat‐shock protein 60 with arterial vascular events in patients with antiphospholipid antibodies
Authors: Dieudé Mélanie , Correa José A. , Neville Carolyn , Pineau Christian , Levine Jerrold S. , Subang Rebecca , Landolt‐Marticorena Carolina , Su Jiandong , Kassis Jeannine , Solymoss Susan , Fortin Paul R. , Rauch Joyce 
Published: April 2011

AbstractObjectiveAnti–heat shock protein 60 autoantibodies (anti‐Hsp60) are associated with cardiovascular disease and are known to affect endothelial cells in vitro, and we have recently shown that anti‐Hsp60 promote thrombosis in a murine model of arterial injury. Based on those findings, we undertook the present study to investigate the hypothesis that the presence of anti‐Hsp60, alone or in combination with other thrombogenic risk factors, is associated with an elevated risk of vascular events.MethodsThe study population was derived from 3 ongoing cohort studies: 2 independent systemic lupus erythematosus (SLE) registries and 1 cohort comprising SLE patients and non‐SLE patients. Data from a total of 402 participants were captured; 199 of these participants had had confirmed vascular events (arterial vascular events in 102, venous vascular events in 76, and both arterial and venous vascular events in 21). Anti‐Hsp60 were detected by enzyme‐linked immunoassay, and association with vascular events was assessed by regression analysis.ResultsMultiple regression analysis revealed that arterial vascular events were associated with male sex, age, and hypertension. Analyses of the vascular events according to their origin showed an association of anti‐Hsp60 with arterial vascular events (odds ratio 2.26 [95% confidence interval 1.13–4.52]), but not with venous vascular events. Anti‐Hsp60 increased the risk of arterial vascular events (odds ratio 5.54 [95% confidence interval 1.89–16.25]) in antiphospholipid antibody (aPL)–positive, but not aPL‐negative, individuals.ConclusionWe demonstrate that anti‐Hsp60 are associated with an increased risk of arterial vascular events, but not venous vascular events, in aPL‐positive individuals. These data suggest that anti‐Hsp60 may serve as a useful biomarker to distinguish risk of arterial and venous vascular events in patients with aPL.
Probing Structures of Small Gold Cluster Cations with Dinitrogen
Authors: Patwari G. Naresh , Ito Tomonori , Egashira Kazuhiro , Terasaki Akira 
Published: April 2011

AbstractSmall gold cluster cations, Aun+, adsorb N2 molecules effectively under multiple collision conditions. The saturation number for N2 adsorption on a gold cluster cation depends on the number of dangling gold atoms and the triangular apexes. The saturation numbers were interpreted to arrive at the geometrical structures of gold cluster cations. The gold cluster cations of sizes 3 and 6 have single isomers, whilst cluster cations with 4, 5, and 7 atoms have two isomers. For the gold cluster cation with six atoms, a higher‐energy and lower‐symmetry structure was observed. The gold cluster cations with eight or more atoms do not adsorb N2, which can be attributed to a two‐dimensional to three‐dimensional structural transition at n=8.
1,3‐Alternate Calix[4]arene as a Homobinuclear Ditopic Fluorescent Chemosensor for Ag+ Ions
Authors: Ho I‐Ting , Haung Kuan‐Chang , Chung Wen‐Sheng 
Published: April 2011

AbstractA novel 1,3‐alternate calix‐[4]arene L, containing two different cationic binding sites of bis‐triazoles and bis‐enaminone groups, was synthesized and shown to be a homobinuclear ditopic fluorescent chemosensor for Ag+ ions. The fluorescence intensity of L was selectively enhanced by binding with Ag+ ions in methanol/chloroform (49:1, v/v) cosolvent. In the presence of most competing metal ions, L retains its selectivity toward Ag+ ion. The binding constants K1 and K2 of the successive complexation of L with the first and second Ag+ ions were calculated to be 4.46×103 and 9.20×104 M−1, respectively. The higher K2 value revealed that a positive allosteric effect participated in the complexation of L with the second equivalent of Ag+. Based on 1H NMR titration results, we inferred that the two distal bis‐enaminone and bis‐triazole groups on L cooperatively coordinated to Ag+ ions with the help of cation–π interactions from the phenoxy rings. Furthermore, the ESI‐MS spectrometry clearly proved the formation of the homobinuclear complex L⋅(Ag+)2, because a base peak at m/z of 750.1701 was detected and its isotope pattern was in excellent agreement with the calculated one.
Design of a two‐level controller for an active suspension system
Authors: Gáspár P. , Szabó Z. , Szederkényi G. , Bokor J. 
Published: April 2011

AbstractThe paper focuses on a control design for a vehicle suspension system in which a balance between different performance demands is achieved. The starting point of the control design is a full–car model which contains nonlinear components, i.e. the dynamics of the dampers and springs and nonlinear actuator dynamics. In order to handle the high complexity of the problem this paper proposes the design of a two‐level controller of an active suspension system. The required control force is computed by applying a high‐level controller, which is designed using a linear parameter varying (LPV) method. For the control design the model is augmented with weighting functions specified by the performance demands and the uncertainty assumptions. The actuator generating the necessary control force is modelled as a nonlinear system for which a low‐level force‐tracking controller is designed. To obtain the low‐level controller a backstepping method is proposed. As an alternative solution a feedback linearization method is also presented. The operation of the controller is illustrated through simulation examples.Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Estimate of Domain of Attraction for a Class of Port‐Controlled Hamiltonian Systems Subject to Both Actuator Saturation and Disturbances
Authors: Wei Airong , Wang Yuzhen , Hu Xiaoming 
Published: April 2011

AbstractThis paper investigates the estimate of domain of attraction for a class of nonlinear port‐controlled Hamiltonian (PCH) systems subject to both actuator saturation and disturbances. Firstly, two conditions are established to determine whether an ellipsoid is contractively invariant for the systems only with actuator saturation, with which the biggest ellipsoid contained in the domain of attraction can be found. Secondly, the obtained conditions are extended to estimate the domain of attraction of the systems subject to both actuator saturation and disturbances. Study of illustrative example shows the effectiveness of the method proposed in this paper.Copyright © 2011 John Wiley and Sons Asia Pte Ltd and Chinese Automatic Control Society
Arginine controls heat‐induced cluster–cluster aggregation of lysozyme at around the isoelectric point
Authors: Tomita Shunsuke , Yoshikawa Hiroki , Shiraki Kentaro 
Published: April 2011

AbstractThe process of protein aggregation has attracted a great deal of research attention, as aggregates are first of all a nuisance to preparation of high quality protein and secondly used as novel materials. In the latter case, the process of protein aggregation needs to be controlled. Here, we show how arginine (Arg) regulates the process of heat‐induced protein aggregation. Dynamic light scattering and transmission electron microscopy revealed that heat‐induced aggregation of lysozyme at around the isoelectric point occurred in a two‐step process: formation of start aggregates, followed by further growth mediated by their sticking with diffusion‐limited cluster–cluster aggregation. In the presence of Arg, the diffusion‐limited regime changed to reaction‐limited cluster–cluster aggregation. The data indicated that the solution additives that coexisted with proteins would affect the property of the formed product, such as morphology and mechanic strength. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 695–701, 2011.
Design, synthesis, in vitro stability and cytostatic effect of multifunctional anticancer drug‐bioconjugates containing GnRH‐III as a targeting moiety
Authors: Leurs Ulrike , Mező Gábor , Orbán Erika , Öhlschläger Peter , Marquardt Andreas , Manea Marilena 
Published: April 2011

AbstractBioconjugates containing the GnRH‐III hormone decapeptide as a targeting moiety are able to deliver chemotherapeutic agents specifically to cancer cells expressing GnRH receptors, thereby increasing their local efficacy while limiting the peripheral toxicity. However, the number of GnRH receptors on cancer cells is limited and they desensitize under continuous hormone treatment. A possible approach to increase the receptor mediated tumor targeting and consequently the cytostatic effect of the bioconjugates would be the attachment of more than one chemotherapeutic agent to one GnRH‐III molecule. Here we report on the design, synthesis and biochemical characterization of multifunctional bioconjugates containing GnRH‐III as a targeting moiety and daunorubicin as a chemotherapeutic agent. Two different drug design approaches were pursued. The first one was based on the bifunctional [4Lys]‐GnRH‐III (Glp‐His‐Trp‐Lys‐His‐Asp‐Trp‐Lys‐Pro‐Gly‐NH2) containing two lysine residues in positions 4 and 8, whose ϵ‐amino groups were used for the coupling of daunorubicin. In the second drug design, the native GnRH‐III (Glp‐His‐Trp‐Ser‐His‐Asp‐Trp‐Lys‐Pro‐Gly‐NH2) was used as a scaffold; an additional lysine residue was coupled to the ϵ‐amino group of 8Lys in order to generate two free amino groups available for conjugation of daunorubicin. The in vitro stability/degradation of all synthesized compounds was investigated in human serum, as well as in the presence of rat liver lysosomal homogenate. Their cellular uptake was determined on human breast cancer cells and the cytostatic effect was evaluated on human breast, colon and prostate cancer cell lines. Compared with a monofunctional compound, both drug design approaches resulted in multifunctional bioconjugates with increased cytostatic effect. © 2011 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 1–10, 2012.
Impact of concentration of oesophageal and gastric cardia cancer surgery on long-term population-based survival
Authors: van de Poll-Franse L V , Lemmens V E P P , Roukema J A , Coebergh J W W , Nieuwenhuijzen G A P 
Published: April 2011

Abstract

Background
The objective was to evaluate the impact of concentration of surgery for oesophageal and gastric cardia cancer on long-term survival in the population-based Eindhoven Cancer Registry area. In contrast to most previous studies, this study aimed to evaluate both surgically and non-surgically treated patients, to avoid the confounding effect of selective referral.

Methods
This retrospective cohort study included all patients diagnosed with oesophageal or gastric cardia cancer between 1995 and 2006. Results for the period 1995–1998 were compared with those for 1999–2006, after concentration of surgery.

Results
Between 1995 and 2006, 2212 patients were registered with the diagnosis, of whom 638 underwent resection. Before 1999, 73·4 per cent of surgically treated patients underwent a resection in a low-volume hospital (fewer than 4 resections per year) and 23·2 per cent were referred to an academic hospital. After concentration, 63·2 per cent of surgically treated patients underwent resection in one of two regional high-volume centres (15–20 resections per year) and 13·8 per cent were referred to an academic hospital. Three-year survival rates increased from 32·0 to 45·1 per cent for patients who had surgery (P = 0·004), and from 13·1 to 17·9 per cent for all included patients (P = 0·026). These improvements remained after adjustment for case mix or (neo)adjuvant treatments, and were similar for patients with squamous cell carcinoma or adenocarcinoma. However, adjustment for annual hospital volume attenuated this association for patients who had surgery.

Conclusion
Concentration of oesophageal and gastric cardia cancer surgery was associated with improvements in long-term, population-based overall survival for surgically as well as non-surgically treated patients, apparently mediated by an increase in volume.
In vitro cell culture pO2 is significantly different from incubator pO2
Authors: Bambrick L. L. , Kostov Y. , Rao G. 
Published: April 2011

AbstractContinuous noninvasive monitoring of peri‐cellular liquid phase pO2 in adherent cultures is described. For neurons and astrocytes, this approach demonstrates that there is a significant difference between predicted and observed liquid phase pO2. Particularly at low gas phase pO2s, cell metabolism shifts liquid phase pO2 significantly lower than would be predicted from the O2 gas/air equilibrium coefficient, indicating that the cellular oxygen uptake rate exceeds the oxygen diffusion rate. The results demonstrate the need for direct pO2 measurements at the peri‐cellular level, and question the widely adopted current practice of relying on setting the incubator gas phase level as means of controlling pericellular oxygen tension, particularly in static culture systems that are oxygen mass transfer limited. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Microfibrous carriers for cell culture: A comparative study
Authors: Wen Yuan , Yang Shang‐Tian 
Published: April 2011

AbstractSmall patches of polyethylene terephthalate (PET) nonwoven microfibrous matrices have excellent properties and can be used as carriers for culturing cells in agitated bioreactors. The microfibrous carriers are highly porous and can provide large surface areas and three‐dimensional space for high‐density cell growth. In this work, the microfibrous carriers and several commercial microcarriers were used to study cell attachment kinetics, growth, and monoclonal antibody production with Chinese hamster ovary cells. Compared with commercial solid and macroporous microcarriers, the microfibrous carriers showed better or similar performances. In addition, the microfibrous carriers provided a wider operable range for agitation rate than commercial microcarriers, effectively protecting cells from shear stress and carrier collisions. In addition, the microfibrous carriers are available at a much lower cost than commercial microcarriers, providing an attractive alternative to microcarrier‐based large‐scale cell cultures. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Application of electrochemically produced aluminum hydroxide gel for prepurification of recombinant synthetic green fluorescent protein produced in tobacco leaves
Authors: Robić Goran , Lacorte Cristiano , Rech Elibio L. , Miranda Everson A. 
Published: April 2011

AbstractThe use of recombinant proteins has increased greatly in recent years, as also have increased the number of techniques and materials used for their production and purification. Among the different types of bioreactors being studied, there is a general consensus among scientists that production in green plant tissues such as leaves is more feasible. However, the presence of chlorophyll and phenolic compounds in plant extracts, which can precipitate and denature the proteins besides damaging separation membranes and gels, makes this technology impracticable on a commercial scale. In the present work, the adsorption to electrochemically produced aluminum hydroxide gel was applied as a prepurification step for recombinant synthetic green fluorescent protein (sGFP), also referred to as enhanced green fluorescent protein, produced in Nicotiana benthamiana leaves. Removal efficiencies of 99.7% of chlorophyll, 88.5% of phenolic compounds, and 38.5% of native proteins from the N. benthamiana extracts were achieved without removing sGFP from the extracts. As electrochemical preparation of aluminum hydroxide gel is a cost‐effective technique, its use can substantially contribute to the development of future production platforms for recombinant proteins produced in green plant tissues of pharmaceutical and industrial interest. © 2011 American Institute of Chemical Engineers Biotechnol. Prog.,, 2011
Drug loading into and drug release from pH‐ and temperature‐responsive cylindrical hydrogels
Authors: Ninawe Pravin R. , Parulekar Satish J. 
Published: April 2011

AbstractHydrogels that undergo deformation upon appropriate changes in pH or temperature have considerable promise as drug delivery vehicles. Drug uptake in swelling and nonswelling cylindrical hydrogels and drug release from these into a target fluid are investigated here. A mathematical model for hydrogel‐solution composite, a composite of a distributed parameter system (cylindrical hydrogel) and a lumped parameter system (surrounding solution), is developed. The polymer network displacement in a swelling/deswelling hydrogel is described by a stress diffusion coupling model. The analytical solution for network displacement is used to predict solvent intake by swelling hydrogels, solvent efflux from deswelling hydrogels, and changes in pressure, porosity, and effective drug diffusivity. These in turn influence drug uptake during and after hydrogel swelling and drug release from hydrogel during and after deswelling. Numerical results illustrate benefits of hydrogel swelling for drug loading and merits of different modes of drug release. Drug uptake and drug release by temperature‐responsive hydrogels are compared with those by hydrogels not subject to deformation. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011