bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of polystyrene‐b‐poly(ethylene oxide) diblock copolymer and investigation of its micellization behavior in water
Authors: Ahmad Farzana , Baloch Musa Kaleem , Jamil M. , Jeon Y.J. 
Published: June 2010

AbstractThe recent studies deal with a diblock copolymer, polystyrene–poly(ethylene oxide). Infrared spectroscopy, proton resonance spectroscopy (1H‐NMR), and laser light scattering techniques have been used to characterize the polymer. It has been concluded that the sample investigated is diblock copolymer polystyrene–poly(ethylene oxide) having molecular mass 1.656 × 104 g/mol and blocks ratio 1 : 2. The micellization behavior is explored through 1H‐NMR, laser light scattering, light absorption, surface tension, and conductance and viscosity measurements. The results conclude that the critical micelles concentration of copolymer is 0.0951 g/dL at 25°C. It has been observed that the surface tension of solution decreases with the temperature and its impact is maxima in dilute concentration region. In addition, new methodologies have been introduced to get accurate critical micelles concentration and critical micelles temperature. © 2010 Wiley Periodicals, Inc., J Appl Polym Sci, 2010
Study on dry spinning and structure of low mole ratio complex of calcium chloride‐polyamide 6
Authors: Yang Zhongkai , Yin Huihui , Li Xiaoning , Liu Zhendong , Jia Qingxiu 
Published: June 2010

AbstractPolyamide 6 (PA 6) filaments with initial modulus around 48 GPa were produced by dry spinning from low mole ratio (MR) complex of calcium chloride and high molecular weight PA 6 (CaCl2‐PA 6) in formic acid. From the results of XRD, DSC, FTIR, and SEM, the complexation of CaCl2‐PA 6 in the MR range of 0.15–0.3 was efficient. The spinnability of the complex solution was excellent, which allowed a maximum draw ratio of 14.4 for as‐spun fibers. After decomplexing and annealing, the birefringence of drawn fiber could reach around 0.08. Porous structure was found in fibers spun from formic acid‐chloroform cosolvent but not observed by using pure formic acid. When MR of CaCl2/PA 6 exceeded 0.3, some irregular particles formed on the fiber surface due to the recrystallization of CaCl2. However, fibers with smooth surface could be obtained when the MR decreased to 0.15. During the process of decomplexing in ethyl alcohol, an axial shrinkage of drawn fibers in a relaxed state was observed. It turned out that this shrinkage could be avoided by decompexing the fibers under tension. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Preparation and fluorescence properties of poly(o‐methyl‐acrylamideyl‐benzoic acid)‐ZnS composites
Authors: Xu Qing‐Feng , Lu Jian‐Mei , Yan Feng , Xia Xue‐Wei , Li Na‐Jun , Wang Li‐Hua , Ding Chun‐Hua 
Published: June 2010

AbstractPoly(o‐methyl‐acrylamideyl‐benzoic acid)‐ZnS (P(o‐MAABA)‐ZnS) nanocomposites have been prepared and characterized. The resultant P(o‐MAABA)‐ZnS nanocomposites in solution show two emissions in the purple‐light area (370 nm) and in the blue‐light area (425 nm), which are assigned to the polymer and ZnS nanoparticles, respectively. The coordination between the polymer and Zn2+ and the surface chemical composition has been studied by Infrared spectroscopy and X‐ray photoelectron spectroscopy (XPS). The particle size of ZnS nanoparticles was homogeneous and the average size was 3.8 nm, which were characterized by UV absorption spectrum and X‐ray Diffraction. The P(o‐MAABA)‐ZnS composites displays good film formability and the films also show two emissions in 370 and 425 nm. After doped with Tb3+, there was effective energy transfer from ZnS nanoparticles to Tb3+. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis and characterizations of nanosized iron(II) hydroxide and iron(II) hydroxide/poly(vinyl alcohol) nanocomposite
Authors: Parveen M. Fathima , Umapathy S. , Dhanalakshmi V. , Anbarasan R. 
Published: June 2010

AbstractNanosized Fe(OH)2 was synthesized by a coprecipitation method. Peaks between 500 and 1250 cm−1 in Fourier transform infrared (FTIR) spectroscopy confirmed the presence of metal hydroxide stretching. X‐ray diffraction showed the suppressed crystalline system of Fe(OH)2/aniline (ANI) due to the presence of a higher weight percentage of the dispersing agent, ANI. Thermogravimetric analysis implied that 75.5 wt % of residue remained up to 800°C. High resolution transmission electron microscope (HRTEM) analysis of Fe(OH)2/ANI revealed that its size ranged from 10 to 50 nm with a rodlike morphology. Scanning electron microscopy implied that pristine Fe(OH)2 had a nanotriangular platelet morphology, and a higher weight percentage of dispersing agent intercalated with Fe(OH)2 had a spheroid with an agglomerated structure. The (UV–visible) spectrum implied the presence of Fe2+ ions at 326 nm and the existence of an amino group intercalated with Fe(OH)2 showed a sharp peak at 195 nm, the intensity of which increased with increasing intercalated dispersing agent weight percentage. Photoluminescence showed that ANI‐intercalated Fe(OH)2 showed a lesser intensity than the pristine Fe(OH)2. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Abrasion and nanoscratch in nanostructured epoxy coatings
Authors: Turri Stefano , Torlaj Luca , Piccinini Francesca , Levi Marinella 
Published: June 2010

AbstractA series of epoxy nanostructured coatings based on diglycidyl ether of bisphenol A (DGEBA) and an isophorone diamine crosslinker was prepared. Top‐down nanocomposites (3% nanofiller) were obtained by the mechanical dispersion of nanoalumina, silanized nanoalumina, and organomodified clays. Bottom‐up hybrids were instead achieved after the silanization of the DGEBA resin and after cocrosslinking with tetraethylorthosilicate through a self‐catalyzed sol–gel process. The curing process of the nanocomposites was studied by differential scanning calorimetry and suggested an overall increase in the crosslinking kinetics in the presence of nanoparticles. Other characterization included dynamic mechanical analysis, Buchholtz indentation hardness testing, and Taber abrasion testing. Finally, atomic force microscopy (AFM) techniques were used to study the surface morphology of the coatings and to produce nanoscratches. We concluded that, in the top‐down nanocomposites, there were minor changes in the surface hardness and a slight improvement in the abrasion resistance, whereas the nanoscratch resistance assessed by AFM tests showed significantly better performances in the hybrid coatings obtained through sol–gel chemistry. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Compatibility study of polypropylene and acrylonitrile butadiene rubber blends
Authors: Motawie A. M. , Abdel‐Aziz M. M. , Rabia A. M. , Mazrous A. M. , Badr M. M. , Sadek E. M. 
Published: June 2010

AbstractBlends of polypropylene (PP) and acrylonitrile butadiene rubber (NBR) were prepared with different weight compositions with a plasticorder at 180°C at a rotor speed of 60 rpm for 8 min. The physicomechanical properties and mass swell of the prepared blends were investigated with special reference to the effects of the blend ratio. The prepared epoxidized linseed oil (EL) (i.e., E0.5L, E1L, E1.5L, and E2L using 0.5, 1, 1.5, and 2 mol H2O2/mole of unsaturation in linseed oil) and maleic acid anhydride (MAH) were melt mixed in various contents (i.e., 1, 5, 10, and 15 wt %) with a PP/NBR blend with a weight ratio of 70/30 and used as compatibilizers. The effect of the compatibilizer contents on the physicomechanical properties and mass swell of the binary blend was investigated. With an increase in the compatibilizer content up to 10 wt %, the blend showed an improvement in the physicomechanical properties and reduced mass swell in comparison with the uncompatibilized one. The addition of a compatibilizer beyond 10 wt % did not improve the blend properties any further. The efficiency of the compatibilizers (10 wt %) was also evaluated by studies of phase morphology (scanning electron microscopy). © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Phase diagrams of poly(ethylene‐co‐vinyl alcohol) and dimethylformamide solutions exhibiting both liquid–liquid and solid–liquid phase separation
Authors: De Lima Juliana Aristéia , Felisberti Maria Isabel 
Published: June 2010

AbstractThe binary solutions of poly(ethylene‐co‐vinyl alcohol) (EVOH), with 38 and 32 wt % ethylene content, and N,N‐dimethylformamide were submitted to experiments to determine the cloud temperature by optical microscopy and the dynamic crystallization temperature by differential scanning calorimetry (DSC). The thermally induced phase separation (TIPS) process was used with the EVOH/DMF solutions that showed liquid–liquid phase separation at temperatures higher than EVOH crystallization and with a decrease of the temperature‐UCST behavior. The binary interaction model was applied to estimate the interaction energy densities (B) considering both intermolecular (ethylene‐Et/DMF and vinyl alcohol‐VA/DMF) and intramolecular (Et/VA) interactions. According to this model the liquid–liquid line for the EVOH‐38/DMF solutions should be situated at higher temperatures in comparison with EVOH‐32/DMF solutions. Moreover, the phase separation results from low affinity between the hydrophobic segments of EVOH and the segments of the copolymer containing hydroxyl or the solvent. The equilibrium melting temperature of EVOH increases with the increase of EVOH volume fraction in the solution. This effect is more pronounced for EVOH‐32/DMF solutions, which means that there is an influence of the VA content in EVOH during the melting. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Gadolinium‐conjugated FA‐PEG‐PAMAM‐COOH nanoparticles as potential tumor‐targeted circulation‐prolonged macromolecular MRI contrast agents
Authors: Zhang Wei‐Lu , Li Na , Huang Jin , Yu Jia‐Hui , Wang Da‐Xin , Li Ya‐Ping , Liu Shi‐Yuan 
Published: June 2010

AbstractThe aim of research is to develop potential tumor‐targeted circulation‐prolonged macromolecular magnetic resonance imaging (MRI) contrast agents without the use of low molecular gadolinium (Gd) ligands. The contrast agents were based on polymer–metal complex nanoparticles with controllable particle size to achieve the active and passive tumor‐targeted potential. In particular, poly (amidoamine) (PAMAM) dendrimer with 32 carboxylic groups was modified with folate‐conjugated poly (ethyleneglycol) amine (FA‐PEG‐NH2, Mw: 2 k and 4 kDa). FA‐PEG‐PAMAM‐Gd macromolecular MRI contrast agents were prepared by the complex reaction between the carboxylic groups in PAMAM and GdCl3. The structure of FA‐PEG‐PAMAM‐COOH was confirmed by nuclear magnetic resonance (1H‐NMR), Fourier transform infrared (FTIR) spectra, and electrospray ionization mass spectra (ESI‐MS). The mass percentage content of Gd (III) in FA‐PEG‐PAMAM‐Gd was measured by inductively coupled plasma‐atomic emission spectrometer (ICP‐AES). The sizes of these nanoparticles were about 70 nm measured by transmission electron microscopy, suggestion of their passive targeting potential to tumor tissue. In comparison with clinically available small molecular Gadopentetate dimeglumine, FA‐PEG‐PAMAM‐Gd showed comparable cytotoxicity and higher relaxation rate, suggestion of their great potential as tumor‐targeted nanosized macromolecular MRI contrast agents due to the overexpressed FA receptor in human tumor cell surfaces. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Investigation and prevention of clogging during electrospinning of zein solution
Authors: Kanjanapongkul Kobsak , Wongsasulak Saowakon , Yoovidhya Tipaporn 
Published: June 2010

AbstractElectrospinning is the only known technique for fabrication of long non‐woven ultrafine‐fibers. However, a number of limitations, including low productivity and clogging of a spinneret, substantially paralyses industrial scale up of the process. Clogging is indeed an unavoidable phenomenon during electrospinning of biopolymers and the exact reason for clogging is still unclear. The aim of the present study was thus to investigate the clogging phenomenon via the study of a solution of zein/ethanol, which was used as a model biopolymer system. The gel‐like substance causing clogging at the spinneret was collected and its infrared spectrum and rheological properties were determined via Fourier transform infrared (FTIR) spectrophotometry and rheometry, respectively. The results indicated that clogging was due to solvent evaporation, which led to formation of a highly viscous semi‐solid at the spinneret. Moreover, the results also revealed that the applied voltage and polymer concentration were the key parameters affecting clogging. A means to help avoid clogging and hence an ability to continuously perform electrospinning was also proposed and tested. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
In vivo microfocal computed tomography and micro–magnetic resonance imaging evaluation of antiresorptive and antiinflammatory drugs as preventive treatments of osteoarthritis in the rat
Authors: Jones Michael D. , Tran Charles W. , Li Guang , Maksymowych Walter P. , Zernicke Ronald F. , Doschak Michael R. 
Published: June 2010

AbstractObjectiveTo determine whether treatment with an antiresorptive drug in combination with an antiinflammatory drug reduces periarticular bone and soft tissue adaptations associated with the progression of posttraumatic secondary osteoarthritis (OA).MethodsWe used in vivo microfocal computed tomography (micro‐CT) to map bony adaptations and in vivo micro–magnetic resonance imaging (micro‐MRI) to examine joint inflammation in a rat model of surgically induced OA secondary to knee triad injury. We examined the arthroprotective effects of the bisphosphonates alendronate and risedronate and the nonsteroidal antiinflammatory drug (NSAID) meloxicam.ResultsMicro‐CT revealed reduced levels of periarticular trabecular bone loss in animals with knee triad injury treated with the bisphosphonate drugs alendronate or risedronate, or the NSAID meloxicam, compared with untreated animals. Alendronate treatment reduced bony osteophyte development. While risedronate as a monotherapy did not positively impact osteophytogenesis, combination therapy with risedronate and meloxicam reduced osteophyte severity somewhat. Micro‐MRI revealed an increased, diffuse water signal in the epiphyses of untreated rats with knee triad injury 8 weeks after surgery, suggestive of a bone marrow lesion–like stimulus. In contrast, meloxicam‐treated rats showed a significant reduction in fluid signal compared with both bisphosphonate‐treated groups 8 weeks after surgery. Histologic analysis qualitatively confirmed the chondroprotective effect of both bisphosphonate treatments, showing fewer degradative changes compared with untreated rats with knee triad injury.ConclusionOur findings indicate that select combinations of bisphosphonate and NSAID drug therapy in the early stages of secondary OA preserve trabecular bone mass and reduce the impact of osteophytic bony adaptations and bone marrow lesion–like stimulus. Bisphosphonate and NSAID therapy may be an effective disease‐modifying drug regimen if administered early after the initial injury.
Local and Remote Charge‐Transfer‐Enhanced Raman Scattering on One‐Dimensional Transition‐Metal Oxides
Authors: Dong Bin , Huang Yingzhou , Yu Naisen , Fang Yurui , Cao Baosheng , Li Yuanzuo , Xu Hongxing , Sun Mengtao 
Published: June 2010

AbstractThe one‐dimensional (1D) transition‐metal oxide MoO3 belt is synthesized and characterized with X‐ray diffraction, scanning electron microscopy, and Raman spectroscopy. Charge‐transfer‐(CT) enhanced Raman scattering of 4‐mercaptobenzoic acid (4‐MBA) on a 1D MoO3 belt was investigated experimentally and theoretically. The chemical enhancement of surface‐enhanced Raman scattering (SERS) of 4‐MBA on the MoO3 belt by CT is in the order of 103. The SERS of 4‐MBA was investigated theoretically by using a quantum chemical method. The remote SERS of 4‐MBA along the 1D MoO3 belt (the light excitation to one side of the MoO3 belt, and the SERS spectrum is collected on the other side of the MoO3 belt) is also shown experimentally, which provides potential applications of SERS. The incident polarization dependence of remote SERS spectra has also been investigated experimentally.
Toxicity of bryostatin‐1 on the embryo‐fetal development of Sprague‐Dawley rats
Authors: Jiangbo Zhu , Xuying Wan , Yuping Zhu , Xili Ma , Yiwen Zheng , Tianbao Zhang 
Published: June 2010

AbstractBACKGROUND: Bryostatin‐1, a highly oxygenated marine macrolide with a unique polyacetate backbone isolated from the marine animal Bugula neritina (Linnaeus), is now being developed as an anti‐cancer drug for treating malignancy. In the present study, developmental toxicity of bryostatin‐1 was evaluated in Sprague–Dawley rats. METHODS: Bryostatin‐1 was intravenously administered to rats on gestation days 6–15 at 4.0, 8.0, and 16.0 µg/kg on a daily basis. Then the reproductive parameters were determined in animals, and fetuses were examined for external, visceral, and skeletal malformations. RESULTS: The total weight gains were significantly different in animals between the control group and 8.0 and 16.0 µg/kg bryostatin‐1 groups during and after treatment. The resorption and death fetus rates were significantly different between the bryostatin‐1 group (16 µg/kg) and the control group. The fetal weight and fetal crown‐rump length in the bryostatin‐1 groups were significantly lower than that in the control group. CONCLUSIONS: Our results indicated that maternal toxicity occurred when the dose of bryostatin‐1 was at 8.0 µg/kg, embryotoxicity at 16.0 µg/kg, and fetotoxicity at 4.0 µg/kg; but bryostatin‐1 showed no teratogenic effect in rats. In light of our findings, bryostatin‐1 should be used with caution in pregnant women with cancer, if they would like to continue the pregnancy. Birth Defects Res (Part B) 89:171–174, 2010. © 2010 Wiley‐Liss, Inc.
Nitrofen induces apoptosis independently of retinaldehyde dehydrogenase (RALDH) inhibition
Authors: Kling David E. , Cavicchio Amanda J. , Sollinger Christina A. , Schnitzer Jay J. , Kinane T. Bernard , Newburg David S. 
Published: June 2010

AbstractBACKGROUND:Nitrofen is a diphenyl ether that induces congenital diaphragmatic hernia (CDH) in rodents. Its mechanism of action has been hypothesized as inhibition of the retinaldehyde dehydrogenase (RALDH) enzymes with consequent reduced retinoic acid signaling.METHODS:To determine if nitrofen inhibits RALDH enzymes, a reporter gene construct containing a retinoic acid response‐element (RARE) was transfected into HEK‐293 cells and treated with varying concentrations of nitrofen in the presence of retinaldehyde (retinal). Cell death was characterized by caspace‐cleavage microplate assays and terminal deoxynucleotidyl transferase dUTP nick end‐labeling (TUNEL) assays. Ex vivo analyses of cell viability were characterized in fetal rat lung explants using Live/Dead staining. Cell proliferation and apoptosis were assessed using fluorescent immunohistochemistry with phosphorylated histone and activated caspase antibodies on explant tissues. Nile red staining was used to identify intracellular lipid droplets.RESULTS:Nitrofen‐induced dose‐dependent declines in RARE‐reporter gene expression. However, similar reductions were observed in control‐reporter constructs suggesting that nitrofen compromised cell viability. These observed declines in cell viability resulted from increased cell death and were confirmed using two independent assays. Ex vivo analyses showed that mesenchymal cells were particularly susceptible to nitrofen‐induced apoptosis while epithelial cell proliferation was dramatically reduced in fetal rat lung explants. Nitrofen treatment of these explants also showed profound lipid redistribution, primarily to phagocytes.CONCLUSIONS:The observed declines in nitrofen‐associated retinoic acid signaling appear to be independent of RALDH inhibition and likely result from nitrofen induced cell death/apoptosis. These results support a cellular apoptotic mechanism of CDH development, independent of RALDH inhibition.Birth Defects Res (Part B)89:223–232, 2010. © 2010 Wiley‐Liss, Inc.
Biofuel production improvement with genome‐scale models: The role of cell composition
Authors: Senger Ryan S. 
Published: June 2010

AbstractGenome‐scale models have developed into a vital tool for rational metabolic engineering. These models balance cofactors and energetic requirements and determine biosynthetic precursor availability in response to environmental and genetic perturbations. In particular, allocation of additional reducing power is an important strategy for engineering potential biofuel production from microbes. Many potential biofuel solvents induce biomolecular changes on the host organism that are not yet captured by genome‐scale models. Here, methods of construction for several biomass constituting equations are reviewed along with potential changes to cellular composition with potential biofuels exposure. The biomass constituting equations of potential host organisms with existing genome‐scale models are compared side‐by‐side to explore their evolution over the years and to explore differences that arise when these equations are compiled by different research groups. Genome‐scale model simulation results attempt to address and provide guidance for further research into: (i) whether inconsistencies in the biomass constituting equations are relevant to predictions of solvent production, (ii) what level of detail is necessary to accurately describe cellular composition, and (iii) future developments that may enable more accurate characterizations of biomolecular composition.
Cellulases of Penicillium verruculosum
Authors: Morozova Valeria V. , Gusakov Alexander V. , Andrianov Ruslan M. , Pravilnikov Artyom G. , Osipov Dmitry O. , Sinitsyn Arkady P. 
Published: June 2010

AbstractNine major cellulolytic enzymes were isolated from a culture broth of a mutant strain of the fungus Penicillium verruculosum: five endo‐1, 4‐β‐glucanases (EGs) having molecular masses 25, 33, 39, 52, and 70 kDa, and four cellobiohydrolases (CBHs: 50, 55, 60, and 66 kDa). Based on amino acid similarities of short sequenced fragments and peptide mass fingerprinting, the isolated enzymes were preliminary classified into different families of glycoside hydrolases: Cel5A (EG IIa, 39 kDa), Cel5B (EG IIb, 33 kDa), Cel6A (CBH II, two forms: 50 and 60 kDa), Cel7A (CBH I: 55 and 66 kDa), Cel7B (EG I: 52 and 70 kDa). The 25 kDa enzyme was identical to the previously isolated Cel12A (EG III). The family assignment was further confirmed by the studies of the substrate specificity of the purified enzymes. High‐molecular‐weight forms of the Cel6A, Cel7A, and Cel7B were found to possess a cellulose‐binding module (CBM), while the catalytically active low‐molecular‐weight forms of the enzymes, as well as other cellulases, lacked the CBM. Properties of the isolated enzymes, such as substrate specificity toward different polysaccharides and synthetic glycosides, effect of pH and temperature on the enzyme activity and stability, adsorption on Avicel cellulose and kinetics of its hydrolysis, were investigated.