bluuebunny/crossref_metadata_2025_split huggingface dataset:
Streptavidin‐Functionalized Silver‐Nanoparticle‐Enriched Carbon Nanotube Tag for Ultrasensitive Multiplexed Detection of Tumor Markers
Authors: Lai Guosong , Wu Jie , Ju Huangxian , Yan Feng 
Published: May 2011

AbstractA streptavidin‐functionalized silver‐nanoparticle‐enriched carbon nanotube (CNT/Ag NP) is designed as trace tag for ultrasensitive multiplexed measurements of tumor markers using a disposable immunosensor array. The CNT/Ag NP nanohybrid is prepared by one‐pot in situ deposition of Ag NPs on carboxylated CNTs. The nanohybrid is functionalized with streptavidin via the inherent interaction between the protein and Ag NPs for further linkage of biotinylated signal antibodies to obtain tagged antibodies. The functionalization process greatly improves the dispersibility of the nanohybrid in water. The immunosensor array is prepared by covalently immobilizing capture antibodies on chitosan‐modified screen‐printed carbon electrodes. Through a sandwich‐type immunoreaction on the immunosensor array, numerous Ag NPs are captured onto every single immunocomplex and are further amplified by a subsequent Ag NP‐promoted deposition of silver from a silver enhancer solution to obtain the sensitive electrochemical‐stripping signal of the Ag NPs. Using carcinoembryonic antigen and α‐fetoprotein as model analytes, this proposed multiplexed immunoassay method shows acceptable precision and wide linear ranges over four orders of magnitude with detection limits down to 0.093 and 0.061 pg mL−1, respectively. The assay results of serum samples with the proposed method are in acceptable agreement with the reference values. The newly designed strategy and the functionalized tag avoid cross‐talk and the requirement of deoxygenation for electrochemical immunoassay, and thus provide a promising potential in clinical application.
Effect of silanes on the morphology, hydrophobicity, and dynamical mechanical properties of polyimide/silica hybrid membranes
Authors: Chen Chiou‐Juy , Lu Hsu‐Tung , Tseng Wen‐Yen , Tseng I‐Hsiang , Huang Shih‐Liang , Tsai Mei‐Hui 
Published: May 2011

AbstractPolyimide (PI)/silica hybrid membranes with high contact angles were prepared through the in situ sol–gel process. The precursor, poly(amic acid) with controlled block chain length, was synthesized using 4,4′‐diaminodiphenyl ether (ODA), 3,3′,4,4′‐benzophenone‐tetracarboxylic dianhydride (BTDA) and 3‐aminopropyl‐trimethoxysilane (APrTMOS) or 3‐aminopropyldimethylethoxysilane (APDiMOS). And then, phenyltrimethoxysilane (PTS) or tetramethoxysilane (TMOS) or methyltrimethoxysilane (MTrMOS) was respectively, added to the above polyamic acid and mixed thoroughly. Following curing reaction, the PI/silica hybrid membranes with different cross‐linkages, silica content, and hydrophobic properties were prepared. The effect on the formation of PI imide ring during imidization reaction is increased as the increase of silanes content and characterized by frequency shiftment and absorbance ratio of Fourier transform infrared (FTIR) measurements. All the hybrid membranes show high transparency though with high silica contents. The storage modulus, tan δ, and damping intensity by DMA measurements are all correlated with silane content or block chain length. And all these membranes with silane content possess high contact angle as compared to pure PI without any silanes added and the contact angles increase with increasing the silane content. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Investigations of thermal degradation behavior and fire performance of halogen‐free flame retardant poly(1,4‐butylene terephthalate) composites
Authors: Yang Wei , Song Lei , Hu Yuan , Lu Hongdian , Yuen Richard K.K. 
Published: May 2011

AbstractThis work aims to develop halogen‐free poly(1,4‐butylene terephthalate) (PBT) composites with enhanced flame retardancy using ecofriendly flame retardants, aluminum hypophosphite (AHP) and melamine derivatives (melamine polyphosphate and melamine cyanurate). Microscale combustion calorimetry and thermal gravimetric analysis/infrared spectrometry (TG‐IR) technique were used to investigate the potential fire hazards of these PBT composites. For the PBT composites with the incorporation of AHP and melamine derivatives, the heat release capacity (HRC) which is an indicator of a material fire hazard was significantly reduced, and the intensities of a variety of combustible or toxic gases detected by TG‐IR technique were remarkably decreased. Moreover, a loading of 20 wt % flame retardant mixture fulfilled the PBT composites high limited oxygen index (LOI) and V‐0 classification in UL 94 testing. An intumescent flame retarded mechanism was speculated in this work, because numerous bubble‐like char residues were found on the surface of the samples containing flame retardant mixture after LOI testing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Thermosensitive properties of semi‐IPN gel composed of amphiphilic gel and thermosensitive polymer in buffer solution
Authors: Takahashi Atsushi , Sakohara Shuji 
Published: May 2011

AbstractIn this study, a semi‐interpenetrating polymer network (semi‐IPN) gel comprising a crosslinked amphiphilic N,N‐dimethylacrylamide‐co‐N‐isopropylacrylamide gel and interpenetrating thermosensitive poly(N‐isopropylacrylamide) (poly(NIPAM)) was prepared. Their thermosensitive behaviors in a buffer solution comprising sodium chloride, sodium citrate, and sodium dodecyl sulfate, which are generally used in biochips, were investigated. At low temperatures, the gel in the buffer solution was absolutely transparent. However, when the gel was heated, it became milky white or opaque without changes in the gel size. It is well known that the network or crosslink distribution of the transparent gel is homogeneous macroscopically, whereas that of the opaque gel is inhomogeneous; in other words, the network of the opaque gel consists of coarse and dense parts. The structural changes in the gel network were confirmed by the temperature dependence of the permeability of the buffer solution through the semi‐IPN gel membrane. The permeability increased stepwise when the gel became opaque due to heating. The structural changes in the semi‐IPN gel network depended on the compositions of the buffer solution and gel, i.e., the copolymerization ratio of NIPAM in the gel and the content of the poly(NIPAM) molecules in the gel. These results suggest that the thermosensitive behaviors of the semi‐IPN gel strongly depend on the interactions between the copolymerized NIPAM in the gel network and the poly(NIPAM) molecules. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Optimization of synthesis and characterization of cassava starch‐graft‐poly(acrylonitrile) using response surface methodology
Authors: Jyothi Alummoottil N. , Sajeev Moothandasery S. , Parvathy Prabha C. , Sreekumar Janardanan 
Published: May 2011

AbstractGraft copolymerization of poly(acrylonitrile) onto cassava starch was carried out with potassium persulphate (PPS) as the free radical initiator using a response surface Box–Behnken design. Different levels of monomer concentration, initiator concentration, and temperature were used, and regression models were generated in terms of these factors, which can be used to predict the grafting level and efficiency at a given level of the factors. The grafted starches were characterized by FTIR, XRD, and SEM analyses and determination of %grafting (%G), N‐content, thermal properties, water and saline solution retention, and rheological properties. Under the conditions used, %G was found to depend only on the temperature used for the reaction. The maximum %G of 120.1 was obtained for the sample synthesized under the following conditions: weight of AN = 0.753 mol/10 g starch, weight of PPS = 0.284 g and temperature = 55°C, and the grafting efficiency was 30.03%. The absorption bands at 2243 cm−1 for the nitrile group (CN) in the FTIR spectra of the products confirmed the grafting reaction. There was a decrease in crystallinity and disappearance of the granular structure after grafting of the starch. The melting temperatures of the graft copolymers determined by differential scanning calorimetry analysis were higher than that of the native starch. The grafted starches exhibited very high thermal stability as observed from the thermogravimetric analysis. The superabsorbent polymer prepared from the grafted starch by alkali saponification exhibited a maximum water absorbency of 636 g/g. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and mechanical properties of high‐performance short ramie fiber‐reinforced polypropylene composites
Authors: Feng Yulin , Hu Yuexin , Zhao Guiyan , Yin Jinghua , Jiang Wei 
Published: May 2011

AbstractShort ramie fiber (RF) was used to reinforce the polypropylene (PP). The composites were prepared in a twin‐screw extruder followed by injection molding. The experimental results showed that both the strength and the modulus of the composites increase considerably with increasing RF content. The tensile strength and flexural strength are as high as 67 and 80 MPa by the incorporation of ramie up to 30 wt %. To the best of our knowledge, this is one of the best results for short natural fiber‐reinforced PP composites. However, the preparation method in this study is more simple and economic. This short RF‐reinforced PP composites extend the application field for short‐nature fiber‐reinforced PP composites. Morphological analysis revealed that it is the high aspect ratio of the fiber and good interfacial compatibility that result in the high performance of the composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Novel assays of thrombogenic pathogenicity in the antiphospholipid syndrome based on the detection of molecular oxidative modification of the major autoantigen β2‐glycoprotein I
Authors: Ioannou Yiannis , Zhang Jing‐Yun , Qi Miao , Gao Lu , Qi Jian Cheng , Yu De‐Min , Lau Herman , Sturgess Allan D. , Vlachoyiannopoulos Panayiotis G. , Moutsopoulos Haralampos M. , Rahman Anisur , Pericleous Charis , Atsumi Tatsuya , Koike Takao , Heritier Stephane , Giannakopoulos Bill , Krilis Steven A. 
Published: May 2011

AbstractObjectiveBeta‐2‐glycoprotein I (β2GPI) constitutes the major autoantigen in the antiphospholipid syndrome (APS), a common acquired cause of arterial and venous thrombosis. We recently described the novel observation that β2GPI may exist in healthy individuals in a free thiol (biochemically reduced) form. The present study was undertaken to quantify the levels of total, reduced, and posttranslationally modified oxidized β2GPI in APS patients compared to various control groups.MethodsIn a retrospective multicenter analysis, the proportion of β2GPI with free thiols in serum from healthy volunteers was quantified. Assays for measurement of reduced as well as total circulating β2GPI were developed and tested in the following groups: APS (with thrombosis) (n = 139), autoimmune disease with or without persistent antiphospholipid antibodies (aPL) but without APS (n = 188), vascular thrombosis without APS or aPL (n = 38), and healthy volunteers (n = 91).ResultsTotal β2GPI was significantly elevated in patients with APS (median 216.2 μg/ml [interquartile range 173.3–263.8]) as compared to healthy subjects (median 178.4 μg/ml [interquartile range 149.4–227.5] [P < 0.0002]) or control patients with autoimmune disease or vascular thrombosis (both P < 0.0001). The proportion of total β2GPI in an oxidized form (i.e., lacking free thiols) was significantly greater in the APS group than in each of the 3 control groups (all P < 0.0001).ConclusionThis large retrospective multicenter study shows that posttranslational modification of β2GPI via thiol‐exchange reactions is a highly specific phenomenon in the setting of APS thrombosis. Quantification of posttranslational modifications of β2GPI in conjunction with standard laboratory tests for APS may offer the potential to more accurately predict the risk of occurrence of a thrombotic event in the setting of APS.
Folate‐targeted nanoparticles show efficacy in the treatment of inflammatory arthritis
Authors: Thomas Thommey P. , Goonewardena Sascha N. , Majoros Istvan J. , Kotlyar Alina , Cao Zhengyi , Leroueil Pascale R. , Baker James R. 
Published: May 2011

AbstractObjectiveTo investigate the uptake of a poly(amidoamine) dendrimer (generation 5 [G5]) nanoparticle covalently conjugated to polyvalent folic acid (FA) as the targeting ligand into macrophages, and to investigate the activity of an FA‐ and methotrexate (MTX)–conjugated dendrimer (G5‐FA‐MTX) as a therapeutic for the inflammatory disease of arthritis.MethodsIn vitro studies were performed in macrophage cell lines and in isolated mouse macrophages to check the cellular uptake of fluorescence‐tagged G5‐FA nanoparticles, using flow cytometry and confocal microscopy. In vivo studies were conducted in a rat model of collagen‐induced arthritis to evaluate the therapeutic potential of G5‐FA‐MTX.ResultsFolate‐targeted dendrimer bound and internalized in a receptor‐specific manner into both folate receptor β–expressing macrophage cell lines and primary mouse macrophages. The conjugate G5‐FA‐MTX acted as a potent antiinflammatory agent and reduced arthritis‐induced parameters of inflammation such as ankle swelling, paw volume, cartilage damage, bone resorption, and body weight decrease.ConclusionThe use of folate‐targeted nanoparticles to specifically target MTX into macrophages may provide an effective clinical approach for antiinflammatory therapy in rheumatoid arthritis.
Blockade of NKG2D ameliorates disease in mice with collagen‐induced arthritis: A potential pathogenic role in chronic inflammatory arthritis
Authors: Andersson Anna K. , Sumariwalla Percy F. , McCann Fiona E. , Amjadi Parisa , Chang Chiwen , McNamee Kay , Tornehave Ditte , Haase Claus , Agersø Henrik , Stennicke Vibeke W. , Ahern David , Ursø Birgitte , Trowsdale John , Feldmann Marc , Brennan Fionula M. 
Published: May 2011

AbstractObjectiveTo assess the role of the activating receptor NKG2D in arthritis.MethodsLevels of NKG2D and its ligands were determined by fluorescence‐activated cell sorting, real‐time polymerase chain reaction, and immunohistochemistry in rheumatoid arthritis (RA) synovial membrane tissue and in paw tissue from arthritic mice. Arthritis was induced in DBA/1 mice by immunization with type II collagen, and mice were treated intraperitoneally with a blocking anti‐NKG2D antibody (CX5) on days 1, 5, and 8 after clinical onset and were monitored for 10 days.ResultsWe demonstrated expression of NKG2D and its ligands on human RA synovial cells and extended this finding to the paws of arthritic mice. Expression of messenger RNA for the NKG2D ligand Rae‐1 was up‐regulated, and NKG2D was present predominantly on natural killer (NK) and CD4+ T cells, in arthritic paw cell isolates. NKG2D was down‐modulated during the progression of collagen‐induced arthritis (CIA). NKG2D expression in arthritic paws was demonstrated by immunohistochemistry. Blockade of NKG2D ameliorated established CIA, with significant reductions in clinical scores and paw swelling. Histologic analysis of arthritic joints from anti‐NKG2D–treated mice demonstrated significant joint protection, compared with control mice. Moreover, anti‐NKG2D treatment significantly reduced both interleukin‐17 production from CD4+ T cells in arthritic paws and splenic NK cell cytotoxic effector functions in vivo and in vitro.ConclusionOur findings indicate that blockade of NKG2D in a murine model and in human explants has beneficial therapeutic potential that merits further investigation in RA.
A continuous cell alkaline lysis, neutralization, and clarification combination process for production of plasmid pUDK‐HGF
Authors: Chunsheng Hu , Qinglin Zhang , Yuxin Lu , Xiaochen Cheng , Yanliang Wang , Tong Zhang , Zuze Wu 
Published: May 2011

AbstractPlasmid DNA for biopharmaceutical applications is produced easily in Escherichia coli bacteria. The cell lysis is the most crucial step for purification of plasmid DNA. In this paper, we describe a continuous cell alkaline lysis, neutralization, and clarification combination process for production of plasmid pUDK‐HGF using hollow fiber ultrafiltration column as a lysis chamber and compare the plasmid DNA yield and homogeneity with the T‐connector and manual processes, respectively. The results show that the plasmid pUDK‐HGF yield of the combination process is 13% higher than manual lysis, twice higher than using T‐connector. When the proportion of lysed cells and neutralization solution is 3:1, the plasmid pUDK‐HGF yield can improve by 70%. This process could be easily scaled up to meet the industrial scale for cell lysis.
A genetic algorithm for the optimization of the thermoinduction protocol for high‐level production of recombinant human‐like collagen from Escherichia coli
Authors: Chi Lei , Fan Dai‐Di , Ma Xiao‐Xuan , Mi Yu , Luo Yan‐E , Zhu Chen‐Hui , Zhu Xiao‐Li , Xue Wen‐Jiao 
Published: May 2011

AbstractProduction of recombinant human‐like collagen (RHLC) by thermoinduction of recombinant Escherichia coli BL 21 during high cell density cultivation was investigated in a 30 L bioreactor. The effects of induction temperature (T), pH, and carbon‐to‐nitrogen molar ratio of the nutrient medium (C/N) were examined. The optimal thermoinduction protocol for RHLC production was determined by using a model coupling genetic algorithm and artificial neural networks. The optimal operating conditions were as follows: maintenance of induction temperature at 42°C for 3 H and then at 39.4°C until the end, induction pH at 7.03, and C/N at 4.8 (mol/mol). The theoretical maximum concentration of RHLC was 12.5 g/L, whereas the experimental value was 12.1 g/L under the optimal induction conditions.
An industrial perspective on bioreactor scale‐down: What we can learn from combined large‐scale bioprocess and model fluid studies
Authors: Noorman Henk 
Published: May 2011

AbstractFor industrial bioreactor design, operation, control and optimization, the scale‐down approach is often advocated to efficiently generate data on a small scale, and effectively apply suggested improvements to the industrial scale. In all cases it is important to ensure that the scale‐down conditions are representative of the real large‐scale bioprocess. Progress is hampered by limited detailed and local information from large‐scale bioprocesses. Complementary to real fermentation studies, physical aspects of model fluids such as air‐water in large bioreactors provide useful information with limited effort and cost. Still, in industrial practice, investments of time, capital and resources often prohibit systematic work, although, in the end, savings obtained in this way are trivial compared to the expenses that result from real process disturbances, batch failures, and non‐flyers with loss of business opportunity. Here we try to highlight what can be learned from real large‐scale bioprocess in combination with model fluid studies, and to provide suitable computation tools to overcome data restrictions. Focus is on a specific well‐documented case for a 30‐m3 bioreactor. Areas for further research from an industrial perspective are also indicated.
Fast and easy protocol for the purification of recombinant S‐layer protein for synthetic biology applications
Authors: Norville Julie E. , Kelly Deborah F. , Knight Thomas F. , Belcher Angela M. , Walz Thomas 
Published: May 2011

AbstractA goal of synthetic biology is to make biological systems easier to engineer. One of the aims is to design, with nanometer‐scale precision, biomaterials with well‐defined properties. The surface‐layer protein SbpA forms 2D arrays naturally on the cell surface of Lysinibacillus sphaericus, but also as the purified protein in solution upon the addition of divalent cations. The high propensity of SbpA to form crystalline arrays, which can be simply controlled by divalent cations, and the possibility to genetically alter the protein, make SbpA an attractive molecule for synthetic biology. To be a useful tool, however, it is important that a simple protocol can be used to produce recombinant wild‐type and modified SbpA in large quantities and in a biologically active form. The present study addresses this requirement by introducing a mild and non‐denaturing purification protocol to produce milligram quantities of recombinant, active SbpA.
Selective detection of gold using genetically engineered bacterial reporters
Authors: Cerminati Sebastián , Soncini Fernando C. , Checa Susana K. 
Published: May 2011

AbstractSalmonella typhimurium harbours a Au‐resistance system whose expression is controlled by GolS, a transcriptional regulator of the MerR family that selectively detects Au with high sensitivity. We developed both Salmonella and genetically engineered Escherichia coli strains as Au‐selective whole‐cell biosensors by coupling the strictly regulated GolS‐dependent golB promoter to the gfp reporter gene. The bio‐reporters were evaluated under different laboratory conditions and calibrated for their use as selective Au detectors. Due to the intrinsic characteristics of the regulatory protein, the transgenic E. coli sensor exhibits low background, high signal‐to‐noise ratio, and improved sensitivity for detection of Au ions in a wide range of concentrations (up to 470 nM) with a calculated detection limit of ∼33 nM (6 µg L−1 or parts per billion) Au(I). The fluorescent Au‐sensing bacteria exhibit also minimal interference by chemically related metals such as Cu or Ag that are commonly found in Au deposits. These highly specific and sensitive Au detectors might allow the development of rapid and robust screening tools to improve discovery and extraction procedures. Biotechnol. Bioeng. 2011;108: 2553–2560. © 2011 Wiley Periodicals, Inc.
Developing a compound‐specific receptor for bisphenol a by directed evolution of human estrogen receptor α
Authors: Rajasärkkä Johanna , Hakkila Kaisa , Virta Marko 
Published: May 2011

AbstractDirected evolution has become a successful approach to alter ligand binding properties of nuclear receptors. In this study, directed evolution was used to generate a mutant human estrogen receptor α library, which was then used to screen for receptors having enhanced responses to the known endocrine‐disrupting chemical, bisphenol A (BPA). A single round of multi‐site mutation was combined with an efficient positive/negative library screening method in which positive growth‐based selection for the desired activity with BPA was combined with flow cytometric removal of cells having undesired activity with the natural ligand, 17β‐estradiol. The screening steps were performed in a Saccharomyces cerevisiae yeast strain containing a genome‐integrated his3‐yEGFP reporter gene fusion construct. A single round of mutation and screening yielded nine mutants with enhanced responses towards BPA but no detectable induction by 17β‐estradiol (up to 90 nM). These BPA‐specific mutant receptors may prove useful in the field of environmental analytics, where they could be used to monitor and evaluate the proportion of BPA in hormonally active samples. Biotechnol. Bioeng. 2011;108: 2526–2534. © 2011 Wiley Periodicals, Inc.