bluuebunny/crossref_metadata_2025_split huggingface dataset:
Morphology and rheology of composites based on anisotropic polymer matrix and different clays
Authors: Vasilyev G. B. , Makarova V. V. , Rebrov A. V. , Picken S. J. , Smirnova N. M. , Malkin A. Ya. , Kulichikhin V. G. 
Published: February 2011

AbstractStructure and rheological properties of hybrids with polymer matrix and layered silicates as filler were studied. Solution containing 60% wt of hydroxypropylcellulose (HPC) in oligomeric polyethyleneglycol (PEG) was used as a matrix. The peculiarity of this study is that the matrix depending on temperature can form different phase states including liquid‐crystalline (LC). So, a possibility of coexistence and superposition of different ordered structures can be realized at different temperatures. Three different fillers were used: natural Na‐montmorillonite (MMT) and organoclays obtained by treating MMT with surfactants varying in polarity of their molecules. Depending on the type of clay, materials with different morphology can be obtained. X‐ray data showed that PEG intercalates all types of clay used whereas penetration of HPC macromolecules into clay galleries during mixing does not occur. Clay modified with more polar surfactant should be treated as the most convenient material to be intercalated by PEG. Rheological studies (included steady‐state and dynamic shear properties in a wide temperature range) demonstrate that composites are viscoplastic materials and the yield stress is observed already at 5% fillers loading. The level of the yield stress depends on the phase state of the matrix being induced by the superposition of structures formed by clay particles as well as by the LC phase (if it exists). The same conclusion can be made on the base of linear oscillatory measurements because the existence of the LC phase and/or the presence of filler lead to a pseudo solid‐like behavior of a system as whole. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
The effect of carbon nanofiber on the thermo‐physical behavior of polyethylene oxide
Authors: Adhikari A. R. , Lozano K. , Chipara M. , Qualls J. 
Published: February 2011

AbstractComposites of polyethylene oxide (PEO) filled with carbon nanofiber (CNF) were prepared using solution mixing followed by melt mixing. The morphology and thermophysical properties of these composites and of pristine polyethylene oxide were analyzed by scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and dynamical mechanical analysis. Crystallization kinetic data were analyzed within the Avrami approximation for the primary stage of crystallization. The influence of CNF on the temperature dependence crystallization of PEO and the tendency of forming three‐dimensional crystallites at higher crystallization temperature were observed. The nucleation features of CNFs dispersed within PEO were investigated by using Lauritzen‐Hoffman nucleation theory. Crystallization activation energies were also computed; the results are in agreement with the Lauritzen–Hoffman theory. Thermogravimetric analysis and dynamical mechanical analysis showed a gradual increase of the thermal stability and of the storage modulus of the polymeric matrix due to the loading with CNFs and formation of a polymer–carbon nanofiber interface. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Short‐term flexural creep behavior and model analysis of a glass‐fiber‐reinforced thermoplastic composite leaf spring
Authors: Subramanian C. , Senthilvelan S. 
Published: February 2011

AbstractPresent work investigated the short‐term flexural creep performance of fiber reinforced thermoplastic injection molded leaf springs. Unreinforced polypropylene, 20 wt % short and 20 wt % long glass fiber reinforced polypropylene materials were injection‐molded into constant thickness varying width mono leaf spring. Short‐term flexural creep tests were performed on molded leaf springs at various stress levels with the aid of in‐house developed fixture integrated with the servo‐hydraulic fatigue machine. Spring rate reduction is reported as an index for the accumulated damage. Experimental creep performance of molded leaf springs for 2 h was utilized to predict the creep performance with the aid of four parameter HRZ model and compared with 24‐h experimental creep data. Test results revealed that HRZ model is sufficient enough to predict short‐time flexural creep performance of engineering products over wide range of stress. Test results also confirmed the suitability of long fiber reinforced thermoplastic material for creep application over other considered materials. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Improved thermal stability and mechanical properties of poly(propylene carbonate) by reactive blending with maleic anhydride
Authors: Yao Meijun , Mai Fang , Deng Hua , Ning Nanying , Wang Ke , Fu Qiang 
Published: February 2011

AbstractTo extend the application of a carbon dioxide sourced environmental friendly polymer: poly (propylene carbonate) (PPC), a small amount of maleic anhydride (MA) was melt blended to end‐cap with PPC to improve its thermal stability and mechanical properties. Thermal and mechanical properties of end‐capped PPC were investigated by TGA, GPC, mechanical test, and DMA. TGA and titration results demonstrate that PPC can be easily end‐capped with MA through simple melt blending. TGA results show that the thermal degradation temperature of PPC could be improved by around 140°C by adding MA. GPC measurement indicates that the molecular weight of PPC can be maintained after blending with MA, where pure PPC experiences a dramatic degradation in molecular weight during melt process. More importantly, the tensile strength of PPC after blending with MA was found to be nearly eight times higher than that of pure PPC. It has approached the mechanical properties of polyolefin polymers, indicating the possibility of replacing polyolefin polymers with PPC for low temperature applications. The method described here could be used to extend the applications of PPC and fight against the well known global warming problem. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Dynamic shear rheological behavior of PP/EPR in‐reactor alloys synthesized by multi‐stage sequential polymerization process
Authors: Bagheri Hamed , Jahani Yousef , Nekoomanesh Haghighi Mehdi , Hakim Shokoofeh , Fan Zhi Qiang 
Published: February 2011

AbstractThe rheological behavior, morphology, and mechanical properties of in‐reactor alloy of polypropylene (PP)/ethylene propylene rubber (EPR) synthesized by multi‐stage sequential polymerization process are studied in this article. The relationship between polymerization parameters, morphology, and rheological properties are evaluated by scanning electron microscopy (SEM) and small amplitude oscillation rheometry in the linear viscoelastic region. The electron microscopy of samples is showed that by increasing switching frequency in polymerization time, the size of EPR particles decrease. By increasing switching frequency, the curves of complex viscosity against angular frequency of samples are shifted to higher values at low range of shear rates with no significant change at higher frequencies in Power‐law region. The modified Cole‐Cole plots revealed the enhanced melt elasticity by increasing switching frequency up to 230°C. The plot of phase angle versus absolute value of complex modulus G* is used for the evaluation of matrix‐droplets interaction at various temperatures. It is observed two different behaviors before and after 230°C which is the evidence of the change in relaxation mechanism of the blend components because of coarsening the rubber particles in the phase separation process. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Cranial Suture Biology of the Aleutian Island Inhabitants
Authors: Cray James , Mooney Mark P. , Siegel Michael I. 
Published: February 2011

AbstractResearch on cranial suture biology suggests there is biological and taxonomic information to be garnered from the heritable pattern of suture synostosis. Suture synostosis along with brain growth patterns, diet, and biomechanical forces influence phenotypic variability in cranial vault morphology. This study was designed to determine the pattern of ectocranial suture synostosis in skeletal populations from the Aleutian Islands. We address the hypothesis that ectocranial suture synostosis pattern will differ according to cranial vault shape. Ales Hrdlicka identified two phenotypes in remains excavated from the Aleutian Island. The Paleo‐Aleutians, exhibiting a dolichocranic phenotype with little prognathism linked to artifacts distinguished from later inhabitants, Aleutians, who exhibited a brachycranic phenotype with a greater amount of prognathism. A total of 212 crania representing Paleo‐Aleuts and Aleutian as defined by Hrdlicka were investigated for suture synostosis pattern following standard methodologies. Comparisons were performed using Guttmann analyses. Results revealed similar suture fusion patterns for the Paleo‐Aleut and Aleutian, a strong anterior to posterior pattern of suture fusion for the lateral‐anterior suture sites, and a pattern of early termination at the sagittal suture sites for the vault. These patterns were found to differ from that reported in the literature. Because these two populations with distinct cranial shapes exhibit similar patterns of suture synostosis it appears pattern is independent of cranial shape in these populations of Homo sapiens. These findings suggest that suture fusion patterns may be population dependent and that a standardized methodology, using suture fusion to determine age‐at‐death, may not be applicable to all populations. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.
Different Localization of ATP Sensitive K+ Channel Subunits in Rat Testis
Authors: Zhou Ming , He Hui‐Jing , Tanaka Osamu , Sekiguchi Masaki , Kawahara Katsumasa , Abe Hiroshi 
Published: February 2011

AbstractATP sensitive K+ (KATP) channels are important linkage of cell membrane excitability to its cellular bioenergetic state. These channels are composed of pore‐forming subunits and regulatory subunits. The present study focused on the cellular expressions and localizations of these subunits in rat testis. RT‐PCR analysis showed that rat testis contained five KATP channel subunits, Kir6.1, Kir6.2, SUR1, SUR2A and SUR2B. Immunoblot assay showed that proteins of Kir6.1, Kir6.2, SUR2A and SUR2B were expressed in rat testis. Immunohistochemistry revealed these KATP channel subunits were positive in different localizations of spermatogenic cells, Sertoli cells and Leydig cells, which implies these subunits playing important roles in spermatogenesis. Co‐localization of Kir6.2 with SUR2B was determined in acrosome or head cap of spermatids by double immunofluorescence analysis by indicating KATP channel might be formed by Kir6.2 and SUR2B in acrosome of spermatids. Different localizations of the KATP channel subunits in the cell membrane and membranous organelles of spermatogenic cells and Sertoli cells indicated the complex and multiple functions of KATP channels in rat testis. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.
Parallel production of biodiesel and bioethanol in palm‐oil‐based biorefineries: life cycle assessment on the energy and greenhouse gases emissions
Authors: Lim Steven , Lee Keat Teong 
Published: February 2011

AbstractThe main objective of this life cycle assessment (LCA) study is to determine the environmental consequences of the inclusion of second‐generation biofuels (bioethanol from palm oil biomass) toward current palm oil biodiesel production through a ‘seed‐to‐wheel’ LCA analysis. Their energy and greenhouse gas (GHG) emission indicators are evaluated with consequential approach for system delimitation. Although all scenarios provide positive environmental impact, it is found that the inclusion of bioethanol production in the current palm oil processing will decrease the net energy ratio (NER) and net carbon emission ratio (NCER) values by 27.5% and 66.6%, respectively. Moreover, carbon emission savings (CES) value is also found to decrease by a total of 21.9%. This indicates that a higher amount of energy input and GHG emissions is actually required for the bioethanol processing than the amount of energy it will produce and the GHG from fossil fuels it will displace. The sensitivity analysis performed on the yields of bioethanol shows that the minimum conversion threshold should be larger than 60% in order to have a higher energy and GHG emission ratio than current palm oil biodiesel processing. Sensitivity analysis on direct land use change and waste‐water treatment is also carried out which discourages the expansion of palm oil plantation to primary forest (including peatland) and emphasizes the need for a biogas harvesting system. Copyright © 2011 Society of Chemical Industry and John Wiley & Sons, Ltd
Pharmacokinetic properties of lutein emulsion after oral administration to rats and effect of food intake on plasma concentration of lutein
Authors: Sato Yuki , Kobayashi Masaki , Itagaki Shirou , Hirano Takeshi , Noda Toshihiro , Mizuno Satoshi , Sugawara Mitsuru , Iseki Ken 
Published: February 2011

AbstractLutein is a carotenoid found mainly in green leafy vegetables and is located in the macula lutea in the human eye. An intake of lutein as food is needed since humans cannot synthesize it de novo. Although lutein has received much attention recently due to its antioxidant activities, little information about the pharmacokinetic properties of lutein is available. Lutein emulsion formulation was used and the pharmacokinetics of lutein emulsion after oral administration to rats was investigated. The bioavailability of lutein using this formulation was calculated to be 5.20%. It was found that a large amount of lutein was accumulated in the intestinal mucosa. The absorption of orally administered compounds in the intestine can be enhanced by interaction with food or food components. Thus, the effect of food intake on the intestinal absorption of lutein was investigated. The plasma concentration of lutein after oral administration of the emulsion formulation was improved significantly by food intake. It is possible that the absorption of lutein in the intestine is improved significantly by some food components. Bile acids may also play important roles in the intestinal absorption of lutein since the absorption of lipophilic compounds such as cholesterol is related to bile acids. The results of these studies should contribute to an improvement of lutein absorption and provide important information for obtaining more effective pharmacological effects of lutein. Copyright © 2011 John Wiley & Sons, Ltd.
Predicting diafiltration solution compositions for final ultrafiltration/diafiltration steps of monoclonal antibodies
Authors: Teeters Mark , Bezila Daniel , Benner Terry , Alfonso Pedro , Alred Patricia 
Published: February 2011

AbstractMany liquid formulations for monoclonal antibodies (MAbs) require the final ultrafiltration/diafiltration step to operate at high protein concentrations, often at or above 100 g/L. When operating under these conditions, the excipient concentrations and pH of the final diafiltered retentate are frequently not equal to the corresponding excipient concentrations and pH of the diafiltration buffer. A model based on the Poisson–Boltzmann equation combined with volume exclusion was extended to predict both pH and excipient concentrations in the retentate for a given diafiltration buffer. This model was successfully applied to identify the diafiltration buffer composition required to achieve the desired pre‐formulated bulk drug substance (retentate) conditions. Predictions were in good agreement with the experimental results, and reduced the number of experimental iterations needed to define the diafiltration buffer composition. Additionally, the predictive model was applied in a sensitivity analysis across ranges of protein charge, protein concentration, and diafiltration buffer pH and excipient concentration. This sensitivity analysis can facilitate the design of experiments for robustness testing, and allow for generalized predictions across classes of molecules such as MAbs. Biotechnol. Bioeng. 2011; 108:1338–1346. © 2011 Wiley Periodicals, Inc.
Development of a dichloroacetic acid‐hemoglobin conjugate as a potential targeted anti‐cancer therapeutic
Authors: Zhang Ning , Palmer Andre F. 
Published: February 2011

AbstractThis work focuses on conjugating the anti‐cancer drug dichloroacetic acid (DCA) to the monocyte/macrophage targeting protein hemoglobin (Hb). The DCA–Hb conjugate carries approximately 12 DCA molecules per Hb tetramer, and binds to haptoglobin (Hp) forming stable DCA–Hb–Hp complexes, in a similar manner to unmodified Hb. The results of this study show that DCA–Hb–Hp is taken up by the monocytic cancer cell line THP‐1, where it depolarizes the mitochondrial membrane potential, thereby inhibiting cancerous cell growth at a comparable level to free DCA. Taken together, the results of this study show promise for the use of the DCA–Hb conjugate as a potential therapeutic to treat monocytic leukemia. Biotechnol. Bioeng. 2011; 108:1413–1420. © 2011 Wiley Periodicals, Inc.
High‐End pH‐controlled delivery of glucose effectively suppresses lactate accumulation in CHO Fed‐batch cultures
Authors: Gagnon Matthew , Hiller Gregory , Luan Yen‐Tung , Kittredge Amy , DeFelice Jordy , Drapeau Denis 
Published: February 2011

AbstractA simple method for control of lactate accumulation in suspension cultures of Chinese hamster ovary (CHO) cells based on the culture's pH was developed. When glucose levels in culture reach a low level (generally below 1 mM) cells begin to take up lactic acid from the culture medium resulting in a rise in pH. A nutrient feeding method has been optimized which delivers a concentrated glucose solution triggered by rising pH. We have shown that this high‐end pH‐controlled delivery of glucose can dramatically reduce or eliminate the accumulation of lactate during the growth phase of a fed‐batch CHO cell culture at both bench scale and large scale (2,500 L). This method has proven applicable to the majority of CHO cell lines producing monoclonal antibodies and other therapeutic proteins. Using this technology to enhance a 12‐day fed‐batch process that already incorporated very high initial cell densities and highly concentrated medium and feeds resulted in an approximate doubling of the final titers for eight cell lines. The increase in titer was due to additional cell growth and higher cell specific productivity. Biotechnol. Bioeng. 2011; 108:1328–1337. © 2011 Wiley Periodicals, Inc.
Targeted cell immobilization by ultrasound microbeam
Authors: Lee Jungwoo , Lee Changyang , Kim Hyung Ham , Jakob Anette , Lemor Robert , Teh Shia‐Yen , Lee Abraham , Shung Koping Kirk 
Published: February 2011

AbstractVarious techniques exerting mechanical stress on cells have been developed to investigate cellular responses to externally controlled stimuli. Fundamental mechanotransduction processes about how applied physical forces are converted into biochemical signals have often been examined by transmitting such forces through cells and probing its pathway at cellular levels. In fact, many cellular biomechanics studies have been performed by trapping (or immobilizing) individual cells, either attached to solid substrates or suspended in liquid media. In that context, we demonstrated two‐dimensional acoustic trapping, where a lipid droplet of 125 µm in diameter was directed transversely toward the focus (or the trap center) similar to that of optical tweezers. Under the influence of restoring forces created by a 30 MHz focused ultrasound beam, the trapped droplet behaved as if tethered to the focus by a linear spring. In order to apply this method to cellular manipulation in the Mie regime (cell diameter > wavelength), the availability of sound beams with its beamwidth approaching cell size is crucial. This can only be achieved at a frequency higher than 100 MHz. We define ultrasound beams in the frequency range from 100 MHz to a few GHz as ultrasound microbeams because the lateral beamwidth at the focus would be in the micron range. Hence a zinc oxide (ZnO) transducer that was designed and fabricated to transmit a 200 MHz focused sound beam was employed to immobilize a 10 µm human leukemia cell (K‐562) within the trap. The cell was laterally displaced with respect to the trap center by mechanically translating the transducer over the focal plane. Both lateral displacement and position trajectory of the trapped cell were probed in a two‐dimensional space, indicating that the retracting motion of these cells was similar to that of the lipid droplets at 30 MHz. The potential of this tool for studying cellular adhesion between white blood cells and endothelial cells was discussed, suggesting its capability as a single cell manipulator. Biotechnol. Bioeng. 2011; 108:1643–1650. © 2011 Wiley Periodicals, Inc.
A limited LCA of bio‐adipic acid: Manufacturing the nylon‐6,6 precursor adipic acid using the benzoic acid degradation pathway from different feedstocks
Authors: van Duuren J.B.J.H. , Brehmer B. , Mars A.E. , Eggink G. , dos Santos V.A.P. Martins , Sanders J.P.M. 
Published: February 2011

AbstractA limited life cycle assessment (LCA) was performed on a combined biological and chemical process for the production of adipic acid, which was compared to the traditional petrochemical process. The LCA comprises the biological conversion of the aromatic feedstocks benzoic acid, impure aromatics, toluene, or phenol from lignin to cis, cis‐muconic acid, which is subsequently converted to adipic acid through hydrogenation. Apart from the impact of usage of petrochemical and biomass‐based feedstocks, the environmental impact of the final concentration of cis, cis‐muconic acid in the fermentation broth was studied using 1.85% and 4.26% cis, cis‐muconic acid. The LCA focused on the cumulative energy demand (CED), cumulative exergy demand (CExD), and the CO2 equivalent (CO2eq) emission, with CO2 and N2O measured separately. The highest calculated reduction potential of CED and CExD were achieved using phenol, which reduced the CED by 29% and 57% with 1.85% and 4.26% cis, cis‐muconic acid, respectively. A decrease in the CO2eq emission was especially achieved when the N2O emission in the combined biological and chemical process was restricted. At 4.26% cis, cis‐muconic acid, the different carbon backbone feedstocks contributed to an optimized reduction of CO2eq emissions ranging from 14.0 to 17.4 ton CO2eq/ton adipic acid. The bulk of the bioprocessing energy intensity is attributed to the hydrogenation reactor, which has a high environmental impact and a direct relationship with the product concentration in the broth. Biotechnol. Bioeng. 2011; 108:1298–1306. © 2011 Wiley Periodicals, Inc.
A highly efficient ADH‐coupled NADH‐recycling system for the asymmetric bioreduction of carbon‐carbon double bonds using enoate reductases
Authors: Tauber Katharina , Hall Melanie , Kroutil Wolfgang , Fabian Walter M.F. , Faber Kurt , Glueck Silvia M. 
Published: February 2011

AbstractThe asymmetric bioreduction of activated alkenes catalyzed by flavin‐dependent enoate reductases from the OYE‐family represents a powerful method for the production of optically active compounds. For its preparative‐scale application, efficient and economic NADH‐recycling is crucial. A novel enzyme‐coupled NADH‐recycling system is proposed based on the concurrent oxidation of a sacrificial sec‐alcohol catalyzed by an alcohol dehydrogenase (ADH‐A). Due to the highly favorable position of the equilibrium of ene‐reduction versus alcohol‐oxidation, the cosubstrate is only required in slight excess. Biotechnol. Bioeng. 2011; 108:1462–1467. © 2011 Wiley Periodicals, Inc.