bluuebunny/crossref_metadata_2025_split huggingface dataset:
Synthesis, characterization, and electrochemical properties of poly(ethylene oxide)‐based polyaniline electrolyte complex
Authors: H. Kunteppa , Roy Aashis S. , H. Devendrappa , Ambika Prasad M. V. N. 
Published: January 2012

AbstractThe polymer electrolyte based poly(ethylene oxide) complexed with conducting polyaniline (PANI) has been prepared in different weight percentages. The complexation is confirmed by Fourier transform infrared spectroscopy (FTIR).The change in morphology is studied by using scanning electron microscopy. The DC conductivity measurements are carried out using Keithley digital multimeter. It is seen that DC conductivity shows exponential behavior for all PEO : PANI complexes. It is observed that among all the PEO : PANI complexes, 50 wt % of PEO in PANI shows highest conductivity. Electrochemical cell parameters for battery applications at room temperature also have been determined. The samples are fabricated for battery application in the configuration of Na:(PEO : PANI):(I2 + C + sample), and their experimental data are measured using Wagner polarization technique. The cell parameters results in an open‐circuit voltage of 0.4 V and a short‐circuit current of 902 μA for PEO : PANI (50 : 50) composite. Hence, these composites can be better candidates for the polymer electrolyte studies. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Molecular simulations of the conformational properties of atactic poly(2‐ethylbutyl methacrylate)
Authors: Karyappa Rahul B. , Natarajan Upendra 
Published: January 2012

AbstractRIS Metropolis Monte Carlo (RMMC) simulations were used to determine the unperturbed theta‐state chain dimensions of atactic stereoconfigurations of poly (2‐ethylbutyl methacrylate) [PEBMA]. Root mean‐squared end‐to‐end distance (〈r2〉o/M)1/2 and characteristic ratio (Cn) were calculated along with the backbone torsion angle distribution. The simulated properties are in very good agreement with experimental results. The values of the PEBMA chain dimensions are in‐between those corresponding ones for poly(n‐butyl methacrylate) and poly (n‐hexyl methacrylate) thereby showing the effect of branching in the side‐chain. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Compatibility, morphology, and crystallization behavior of compatibilized β‐nucleated polypropylene/poly(trimethylene terephthalate) blends
Authors: Lin Zhidan , Chen Chao , Li Baicheng , Guan Zixian , Huang Zhuoyao , Zhang Meng , Li Xue , Zhang Xiuju 
Published: January 2012

Abstractβ‐Nucleated polypropylene (PP), uncompatibilized β‐nucleated PP/poly(trimethylene terephthalate) (PTT), β‐nucleated PP/PTT blends compatibilized with maleic anhydride (MA)‐grafted PP (PP‐g‐MA), and styrene–ethylene–propylene copolymer were prepared with a twin‐screw extruder. The morphology, compatibility, crystallization characteristic, melting behavior, and crystallization kinetics were investigated. The result shows that β‐nucleated PP was incompatible with PTT, and the addition of the two compatibilizers decreased the interfacial tension between β‐nucleated PP and PTT; this led to improved dispersion and strengthened interfacial bonding in the blends. PP‐g‐MA had a better compatibilization effect. All of the researched β‐nucleated PP/PTT blends contained β crystals of PP, and the compatibilizers exhibited synergistic effects with the β‐nucleating agent to further increase the content of β crystals. Nonisothermal kinetic analysis indicated that Mo's method described the nonisothermal crystallization behavior of the β‐nucleated PP/PTT blends satisfactorily, and the Avrami approach could only describe the early stage of the crystallization appropriately, whereas the Ozawa method failed to have the same effect. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Application of chitosan‐coated quartz sand for Congo red adsorption from aqueous solution
Authors: Feng Tao , Zhang Fan , Wang Jie , Wang Li 
Published: January 2012

AbstractThe preparation, characterization, and environmental application of chitosan‐coated quartz sand for Congo red adsorption have been investigated. The absorbent was characterized by Fourier transform infrared spectrophotometer (FTIR) and scanning electron microscope (SEM). The experiments were carried out in a batch system to optimize operation variables: contact time, Congo red concentration, absorbent dosage, temperature, and pH. The optimum conditions for Congo red adsorption were pH 5, 45°C and contact time of 4 h. An amount of 1 g of chitosan‐coated quartz sand could successfully remove 96% of the dye form 50 mg/L Congo red solution. The adsorption kinetics and equilibrium isotherms showed that the sorption processes were better fitted by pseudo‐second order equation and Langmuir equation, respectively. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Investigation on effects of aluminum and magnesium hypophosphites on flame retardancy and thermal degradation of polyamide 6
Authors: Li Qifei , Li Bin , Zhang Shengqiang , Lin Mo 
Published: January 2012

AbstractTwo hypophosphites, aluminum hypophosphite (AlHP) and magnesium hypophosphite (MgHP), were applied to obtain flame retardant polyamide 6 (FR‐PA6) composites. UL‐94 and limiting oxygen index results indicated that AlHP contributed both good flame retardance and antidripping ability for PA6, while MgHP did not. Based on thermogravimetric analysis (TGA), AlHP and MgHP presented the different thermal degradation behavior. That is, the quick decomposition of AlHP took place at lower temperature than that of MgHP. AlHP promoted the early thermal degradation of PA6 and formed more char residue. The thermal decomposition mechanisms of AlHP and MgHP in nitrogen or air were suggested. Scanning electron microscope and X‐ray photoelectron spectroscopy indicated that in the existence of AlHP, the morphological structures of char residue were more homogenous, and compact, and more char residue was formed. These results well illustrated the difference of the flame retardancy between AlHP and MgHP. Mechanical properties of PA6/AlHP and PA6/MgHP were also obtained. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Covalent immobilization of β‐galactosidase onto amino‐functionalized PVC microspheres
Authors: Mohy Eldin M. S. , Elaassar M. R. , Elzatahry A. A. , Al‐Sabah M. M. B. , Hassan E. A. 
Published: January 2012

Abstractβ‐Galactosidase enzyme, from Aspergillus oryzae, was covalently immobilized onto amino‐functionalized PVC microspheres after activation with gultaraldehyde. PVC microspheres were functionalized by introducing terminal amine groups via amination process with ethylene diamine (EDA). Furthermore, verifications of amination process were obtained using TGA, FT‐IR, and SEM analysis. Different factors affecting the amination process were investigated and their impact on the activity and the retention of immobilized enzyme's activity was monitored. Concentration of ethylene diamine, amination temperature, and time were found for a determined effect. Reaction with EDA (0.025%) at 30°C for 40 minutes was found for optimum conditions. Variation of PVC : EDA mass ratio over 1 : 1 was found with neglectable effect. Thermal stability of immobilized enzyme was recognized where the immobilized form kept 80% of its original activity compared with 20% for the free form. Denaturation tolerance against pH was observed where immobilized form kept 60% of its original activity after 300 minutes incubation at pH 7.0 in the absence of substrate while the free form kept only 15% of its activity under the same conditions. Moreover, immobilized form show storage stabilities where immobilized form kept 40% of its original activity after four weeks while the free form kept only 25% of its initial activity. Under optimum conditions for enzyme immobilization, 1 kg of immobilized enzyme retains 87% of its native activity and has 11,000 activity units. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Thermal characterization of SBR/NBR blends reinforced with a mesoporous silica
Authors: Perez Leon D. , Lopez Betty L. 
Published: January 2012

AbstractIn this article, blends of styrene butadiene rubber (SBR) and acrylonitrile butadiene rubber (NBR) filled with a mesoporous silica are characterized by using scanning electron microscopy (SEM), dynamic mechanical analysis, and differential scanning calorimetry. According to the variation of the glass transition temperature with the composition of the blends, it is deduced that the compatibility of SBR and NBR is reduced in the presence of mesoporous silica. Analysis of the morphology of the composites by SEM shows that the dispersion of the filler is improved in the presence of NBR which is an indicative that this elastomer interacts stronger with silica than SBR. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Changes in the diet of a recovering Eurasian otter population between the 1970s and 2010
Authors: Almeida David , Copp Gordon H. , Masson Laurence , Miranda Rafael , Murai Mizuki , Sayer Carl D. 
Published: January 2012

ABSTRACT

Diet is an essential element for understanding how the Eurasian otter (Lutra lutra) is re‐colonizing its former range in England following a population decline observed in the 1950s to 1970s.
Otter spraints from the River Glaven catchment (north Norfolk, eastern England) were collected seasonally between 2009 and 2010 from three habitat types (ponds, ‘retenus’ (small in‐stream reservoirs), and stream stretches). Feeding tactics of the otter were compared between habitat types and, using previously published data, with regard to seasonal changes since the 1970s when the species was in decline.
Otter diet composition varied greatly, with predation on aquatic invertebrates, crayfish, fish, and tetrapods. Fruit seeds were also found in the spraints. Diet generally reflected habitat, with northern pike (Esox lucius) remains found in spraints from ponds and retenus, whereas European eel (Anguilla anguilla) and gudgeon (Gobio gobio) were prominent in spraints from stream sections. Trophic diversity was particularly high in spraints collected next to ponds. Between the 1970s and the present, crayfish, brown trout (Salmo trutta), cyprinids, Eurasian perch (Perca fluviatilis), birds and mammals increased in prominence, whereas eel and threespine stickleback (Gasterosteus aculeatus) decreased, with notable seasonal variations between the study periods.
Otter spraints revealed few prey preferences, with only that for gudgeon being ecologically relevant. The consumption of popular sport fishes, in particular common carp (Cyprinus carpio), has given rise to conflicts between recreational anglers and otter conservationists, but no demonstrated preference for carp was observed in the present study.
Overall, otters have increased their consumption of ‘less preferred’ (i.e. lower energetic value) food types, and because the species normally preys on the most abundant species available, this suggests declines in ‘preferred’ prey types. These dietary shifts could contribute to otter dispersal and re‐colonization of parts of its original European range where food availability may be higher. © 2012 Crown copyright.
Combined in silico modeling and metabolomics analysis to characterize fed‐batch CHO cell culture
Authors: Selvarasu Suresh , Ho Ying Swan , Chong William P. K. , Wong Niki S. C. , Yusufi Faraaz N. K. , Lee Yih Yean , Yap Miranda G. S. , Lee Dong‐Yup 
Published: January 2012

AbstractThe increasing demand for recombinant therapeutic proteins highlights the need to constantly improve the efficiency and yield of these biopharmaceutical products from mammalian cells, which is fully achievable only through proper understanding of cellular functioning. Towards this end, the current study exploited a combined metabolomics and in silico modeling approach to gain a deeper insight into the cellular mechanisms of Chinese hamster ovary (CHO) fed‐batch cultures. Initially, extracellular and intracellular metabolite profiling analysis shortlisted key metabolites associated with cell growth limitation within the energy, glutathione, and glycerophospholipid pathways that have distinct changes at the exponential‐stationary transition phase of the cultures. In addition, biomass compositional analysis newly revealed different amino acid content in the CHO cells from other mammalian cells, indicating the significance of accurate protein composition data in metabolite balancing across required nutrient assimilation, metabolic utilization, and cell growth. Subsequent in silico modeling of CHO cells characterized internal metabolic behaviors attaining physiological changes during growth and non‐growth phases, thereby allowing us to explore relevant pathways to growth limitation and identify major growth‐limiting factors including the oxidative stress and depletion of lipid metabolites. Such key information on growth‐related mechanisms derived from the current approach can potentially guide the development of new strategies to enhance CHO culture performance. Biotechnol. Bioeng. 2012; 109:1415–1429. © 2012 Wiley Periodicals, Inc.
Metabolic profiling reveals growth related FAME productivity and quality of Chlorella sorokiniana with different inoculum sizes
Authors: Lu Shuhuan , Wang Jiangxin , Niu Yanhong , Yang Jie , Zhou Jian , Yuan Yingjin 
Published: January 2012

AbstractInoculum size strongly affects cell growth and lipid accumulation of microalgae, one of the most potential biodiesel feedstock, however, the metabolic mechanism(s) of the lipid biosynthesis upon inoculum size has not been fully explored yet. The effects of inoculum size on cell growth, lipid accumulation, and metabolic changes of a green microalga Chlorella sorokiniana were investigated. In our experimental range of inoculum size, the productivity and the cetane number (CN) of fatty acid methyl esters (FAME) increased with increasing initial cell density, and the inoculum of 1 × 107 cells mL−1 processed much higher productivity (up to 2.02‐fold) and CN (up to 1.19‐fold) of the FAME than the others. A significant correlation between the metabolic profile and quantity and quality of lipid production was revealed by partial least‐squares to latent structures (PLS) analysis, and 15 key metabolites were identified. Most of those metabolites were involved in the photosynthetically fixed carbon metabolism. Furthermore, light intensity as one of the vital limitation factors for the high inoculum size cultivation was evaluated by illumination assay and the results revealed that increasing light intensity could improve the polyunsaturated fatty acids composition and lipid accumulation of C. sorokiniana. The lipid productivity of the culture was improved by 71.21% with the light intensity of 110 µmol m−2 s−1, compared to that under the irradiance of 65 µmol m−2 s−1. Biotechnol. Bioeng. 2012; 109:1651–1662. © 2012 Wiley Periodicals, Inc.
Engineering novel Lec1 glycosylation mutants in CHO–DUKX cells: Molecular insights and effector modulation of N‐acetylglucosaminyltransferase I
Authors: Zhong Xiaotian , Cooley Cecilia , Seth Nilufer , Juo Z. Sean , Presman Ella , Resendes Nicole , Kumar Ravi , Allen Martin , Mosyak Lidia , Stahl Mark , Somers Will , Kriz Ronald 
Published: January 2012

AbstractMany secreted or cell surface proteins are post‐translationally modified by carbohydrate chains which are a primary source of heterogeneity. The Lec1 mutant, which is defective in Golgi N‐acetylglucosaminyltransferase I (GnTI) activity, produces relatively homogeneous Man5GlcNAc2 glycan modifications, and is widely used for various applications. To facilitate the investigation of GnTI, its Man5 glycan endproduct, and the impact of Man5 on effector function, the present study has established several novel Lec1 mutants in dhfr− CHO–DUKX cells through chemical mutagenesis and lectin selection. A total of nine clonal lines exhibiting the Lec1‐phenotype are characterized, six of which harbor non‐sense mutations leading to a truncated GnTI, and three (R415K, D291N, and P138L) of which are novel loss‐of‐function sense mutations. Analysis of the rabbit GnTI structure (Unligil et al., 2000) indicates that D291 is the proposed catalytic base and R415 is a crucial residue in forming the substrate binding pocket, whereas P138 is key to maintaining two β strands in proximity to the substrate binding pocket. Computational modeling reveals that the oligomannose glycan backbone of a glycoprotein (the acceptor substrate) fits nicely into the unoccupied channel of the substrate binding pocket partly through hydrogen bonding with R415 and D291. This finding is consistent with the ordered sequential Bi Bi kinetic mechanism suggested for GnTI, in which binding of UDP–GlcNAc (the donor substrate)/Mn2+ induces conformational changes that promote acceptor binding. When an anti‐human CD20 antibody protein is stably expressed in one CHO–DUKX–Lec1 line, it is confirmed that N‐glycans are predominantly Man5GlcNAc2 and they do not contain an α1,6‐fucose linked to the innermost GlcNAc. Furthermore, this Man5GlcNAc2 modified antibody exhibits a significantly increased ADCC activity than the wild‐type protein, while displaying a lower CDC activity. The data support the hypothesis that modulating GnTI activity can influence antibody effector functions for proteins with an IgG1 immunoglobulin Fc domain. Biotechnol. Bioeng. 2012; 109:1723–1734. © 2012 Wiley Periodicals, Inc.
Prediction of dynamic metabolic behavior of Pediococcus pentosaceus producing lactic acid from lignocellulosic sugars
Authors: Adler Philipp , Song Hyun‐Seob , Kästner Katharina , Ramkrishna Doraiswami , Kunz Benno 
Published: January 2012

AbstractA dynamic metabolic model is presented for Pediococcus pentosaceus producing lactic acid from lignocellulose‐derived mixed sugars including glucose, mannose, galactose, arabinose, and xylose. Depending on the pairs of mixed sugars, P. pentosaceus exhibits diverse (i.e., sequential, simultaneous or mixed) consumption patterns. This regulatory behavior of P. pentosaceus is portrayed using the hybrid cybernetic model (HCM) framework which views elementary modes of the network as metabolic options dynamically modulated. Comprehensive data are collected for model identification and validation through fermentation experiments involving single substrates and various combinations of mixed sugars. Most sugars are metabolized rather sequentially while co‐consumption of galactose and arabinose is observed. It is demonstrated that the developed HCM successfully predicts mixed sugar data based on the parameters identified mostly from single substrate data only. Further, we discuss the potential of HCMs as a tool for predicting intracellular flux distribution with comparison with flux balance analysis. © 2012 American Institute of Chemical Engineers Biotechnol. Prog., 2012
Antioxidant Phenolic Compounds from the Stems of Entada phaseoloides
Authors: Dong Yuqiong , Shi Haiming , Yang Haisha , Peng Yunhua , Wang Mengyue , Li Xiaobo 
Published: January 2012

AbstractThe EtOH extract of the stems of Entada phaseoloides displayed potent antioxidant activity when assessed by the 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and 2,2′‐azinobis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) radical‐scavenging, reducing power, β‐carotene‐bleaching, and superoxide radical‐scavenging analyses. Fractionation of the EtOH extracts showed that the AcOEt fraction is the most active, followed by the H2O fraction, while BuOH fraction was least active. Further activity‐guided fractionation studies on the active fractions resulted in the isolation of 22 compounds. The identities of these compounds were established based on extensive spectroscopic studies. Furthermore, the antioxidant activities of the isolated compounds were evaluated by using the above‐mentioned five assays. The results demonstrated that the EtOH extract of E. phaseoloides stems exhibits an excellent antioxidant activity and thus presents a great potential as a source of natural antioxidants.
Haemolytic Activity and Immunological Adjuvant Effect of a New Steroidal Saponin from Allium ampeloprasum var. porrum
Authors: Adão Camila Rodrigues , Pereira da Silva Bernadete , Tinoco Luzineide Wanderley , Parente José Paz 
Published: January 2012

AbstractA new steroidal saponin was isolated from the bulbs of Allium ampeloprasum L. var. porrum. On the basis of chemical evidence, comprehensive spectroscopic analyses, and comparison with known compounds, its structure was established as (3β,5α,6β,25R)‐3‐{(O‐β‐D‐glucopyranosyl‐(1→3)‐β‐D‐glucopyranosyl‐(1→2)‐O‐[O‐β‐D‐glucopyranosyl‐(1→3)]‐O‐β‐D‐glucopyranosyl‐(1→4)‐β‐D‐galactopyranosyl)oxy}‐6‐hydroxyspirostan‐2‐one (1). Results of the present study indicated that 1 exhibited haemolytic activity in the in vitro assays, and immunological adjuvant activity on the cellular immune response against ovalbumin antigen.
One‐Pot Synthesis of New (1,3‐Thiazolo[5,4‐b]pyridin‐2‐yl)benzenediols and Their Antiproliferative Activities against Human Cancer Cell Lines
Authors: Matysiak Joanna , Karpińska Monika M. , Niewiadomy Andrzej , Wietrzyk Joanna , Kłopotowska Dagmara 
Published: January 2012

AbstractA one‐pot synthesis of new 4‐(1,3‐thiazolo[5,4‐b]pyridin‐2‐yl)benzene‐1,3‐diols has been described. The compounds were prepared by the reaction of sulfinylbis[(2,4‐dihydroxyphenyl)methanethione] derivatives, with various substituents in the aryl rings, with 2‐chloropyridin‐3‐amines. Their structures were deduced from IR and, 1H‐ and 13C‐NMR spectroscopic, mass spectrometric, and elemental analyses. The antiproliferative properties of some of the products against human cancer cell lines were comparable to those of cisplatin. Structureactivity analysis showed that the presence of hydrophobic substituents in both heterocyclic fused and phenyl rings of the compounds improves their biological effects. Further, an additional OH group in the resorcinol moiety reduced the antiproliferative activity.
New Insights into the Characterization of ‘Insoluble Black HCN Polymers’
Authors: Ruiz‐Bermejo Marta , de la Fuente José L. , Rogero Celia , Menor‐Salván César , Osuna‐Esteban Susana , Martín‐Gago José A. 
Published: January 2012

AbstractThe data presented here provide a novel contribution to the understanding of the structural features of HCN polymers and could be useful in further development of models for prebiotic chemistry. The interpretation of spectroscopic and analytical data, along with previous results reported by other authors, allowed us to propose a mechanism for the aqueous polymerization of HCN from its primary and simplest isolated oligomer, the diaminomaleonitrile (DAMN) tetramer. We suggest that ‘insoluble black HCN polymers’ are formed by an unsaturated complex matrix, which retains a significant amount of H2O and important bioorganic compounds or their precursors. This polymeric matrix can be formed by various motifs of imidazoles and cyclic amides, among others. The robust formation of HCN polymers assayed under several conditions seems to explain the plausible ubiquity of these complex substances in space.