bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical and experimental study on spout elevation in spout‐fluidized beds
Authors: van Buijtenen M.S. , Buist K. , Deen N.G. , Kuipers J.A.M. , Leadbeater T. , Parker D.J.
Published: August 2011

The effect of elevating the spout on the dynamics of a spout‐fluidized bed, both numerically and experimentally is studied. The experiments were conducted in a pseudo‐two‐dimensional (2‐D) and a cylindrical three dimensional (3‐D) spout‐fluidized bed, where positron emission particle tracking (PEPT) and particle image velocimetry (PIV) were applied to the pseudo‐2‐D bed, and PEPT and electrical capacitance tomography (ECT) to the cylindrical 3‐D bed. A discrete particle model (DPM) was used to perform full 3‐D simulations of the bed dynamics. Several cases were studied, that is, beds with spout heights of 0, 2, and 4 cm. In the pseudo‐2‐D bed, the spout‐fluidization and jet‐in‐fluidized‐bed regime, were considered first, and it was shown that in the spout–fluidization regime, the expected dead zones appear in the annulus near the bottom of the bed as the spout is elevated. However, in the jet‐in‐fluidized‐bed regime, the circulation pattern of the particles is affected, without the development of stagnant zones. The jet‐in‐fluidized‐bed regime was further investigated, and additionally the experimental results obtained with PIV and PEPT were compared with the DPM simulation results. The experimental results obtained with PIV and PEPT agreed mutually very well, and in addition agreed well wtih the DPM results, although the velocities in the annulus region were slightly over predicted. The latter is probably due to the particle‐wall effects that are more dominant in pseudo‐2‐D systems compared with 3‐D systems. In the jet‐in‐fluidized‐bed regime, the background gas velocity is relatively high, producing bubbles in the annulus that interact with the spout channel. In the case of a non elevated spout, this interaction occurs near the bottom of the bed. As the spout is elevated, this interaction is shifted upwards in the bed, which allows the bubbles to remain undisturbed providing the motion of the particles in the annulus near the bottom of the bed. As a result, no dead zones are created and additionally, circulation patterns are vertically stretched. These findings were also obtained for the cylindrical 3‐D bed; although, the effects were less pronounced. In the cylindrical 3‐D bed the PEPT results show that the effect on the bed dynamics starts at hspout =1 4 cm, which is confirmed by the ECT results. Additionally, ECT measurements were conducted for hspout =1 6 cm to verify if indeed the effect happens at larger spout heights. The root mean square of the particle volume fraction slightly increased at hspout =1 2 cm, whereas a larger increase is found at hspout = 4 and 6 cm, showing that indeed more bubbles are formed. The presented results have not been reported so far and form valuable input information for improving industrial granulators. © 2011 American Institute of Chemical Engineers AIChE J, 58: 2524–2535, 2012
Intergenerational influences on diabetes in a developing population: The Guangzhou Biobank Cohort Study
Authors: Kavikondala S. , Jiang C.Q. , Zhang W.S. , Cheng K.K. , Lam T.H. , Leung G.M. , Schooling C.M.
Published: August 2011

Objectives:

Intergenerational “mismatch” and/or growth conditions may be relevant to the epidemic of diabetes in developing populations. In a rapidly developing southern Chinese population, we tested whether maternal environment, proxied by maternal literacy, or family socio‐economic position (SEP), proxied by paternal literacy, were associated with fasting glucose and diabetes. To assess if intergenerational mismatch contributed, we tested whether the associations varied by life course SEP.

Methods:

In 19,818 older (≥50 years) adults from the Guangzhou Biobank Cohort Study (phases 2 and 3), we used censored and logistic regression to assess the associations of maternal and paternal literacy with fasting glucose, elevated fasting glucose and diabetes and whether these associations varied by sex, age or life course SEP.

Results:

Maternal, but not paternal, literacy was negatively associated with fasting plasma glucose (β‐coefficient −0.06 mmol/l, 95% confidence interval (CI) −0.11 to −0.01) and elevated fasting glucose (odds ratio (OR) 0.92, 95% CI 0.86–0.99) adjusted for age, sex, study phase, life course SEP, childhood growth, adiposity, number of offspring, and birth order. Associations of maternal and paternal literacy with fasting glucose, elevated fasting glucose and diabetes did not vary by sex, age or life course SEP.

Conclusion:

Offspring of literate mothers had lower risk for impaired glucose tolerance than offspring of illiterate mothers. Being raised by literate mothers may increase the likelihood of children with higher SEP and lower long‐term disease risk, or better maternal conditions over generations may be associated with lower fasting glucose. Am. J. Hum. Biol., 2011. © 2011 Wiley‐Liss, Inc.
Positive association of Phencyclidine‐responsive genes, PDE4A and PLAT, with schizophrenia
Authors: Deng Xiangdong , Takaki Hiromi , Wang Lixiang , Kuroki Tosihide , Nakahara Tatsuo , Hashimoto Kijiro , Ninomiya Hideaki , Arinami Tadao , Inada Toshiya , Ujike Hiroshi , Itokawa Masanari , Tochigi Mamoru , Watanabe Yuichiro , Someya Toshiyuki , Kunugi Hiroshi , Iwata Nakao , Ozaki Norio , Shibata Hiroki , Fukumaki Yasuyuki
Published: August 2011

As schizophrenia‐like symptoms are produced by administration of phencyclidine (PCP), a noncompetitive antagonist of N‐methyl‐D‐aspartate (NMDA) receptors, PCP‐responsive genes could be involved in the pathophysiology of schizophrenia. We injected PCP to Wistar rats and isolated five different parts of the brain in 1 and 4 hr after the injection. We analyzed the gene expression induced by the PCP treatment of these tissues using the AGILENT rat cDNA microarray system. We observed changes in expression level in 90 genes and 21 ESTs after the treatment. Out of the 10 genes showing >2‐fold expressional change evaluated by qRT‐PCR, we selected 7 genes as subjects for the locus‐wide association study to identify susceptibility genes for schizophrenia in the Japanese population. In haplotype analysis, significant associations were detected in combinations of two SNPs of BTG2 (P = 1.4 × 10−6), PDE4A (P = 1.4 × 10−6), and PLAT (P = 1 × 10−3), after false discovery rate (FDR) correction. Additionally, we not only successfully replicated the haplotype associations in PDE4A (P = 6.8 × 10−12) and PLAT (P = 0.015), but also detected single‐point associations of one SNP in PDE4A (P = 0.0068) and two SNPs in PLAT (P = 0.0260 and 0.0104) in another larger sample set consisting of 2,224 cases and 2,250 controls. These results indicate that PDE4A and PLAT may be susceptibility genes for schizophrenia in the Japanese population. © 2011 Wiley‐Liss, Inc.
Dietary breadth and resource use of François' langur in a seasonal and disturbed habitat
Authors: Hu Gang
Published: August 2011

Previous studies of Trachypithecus species indicated that they were selective feeders that concentrated on relatively few food species/items. From January to December 2005, I quantified potential food availability and the food species/items eaten by five groups of François' langur (Trachypithecus francoisi) in the Mayanghe Nature Reserve (MNR), People's Republic of China. These langurs fed on 164 species, of which the top ten accounted for 51% of all feeding records. Langurs consumed more species (91) in the spring than in other seasons (73 summer, 75 autumn, and 67 winter), and only 38 species were consumed in all seasons. Nontree food species, such as bushes and lianas, accounted for 47% of the total feeding records and for a majority (68%) of the feeding records in winter. The annual diet consisted of leaves (64% of feeding records), fruit and seed (32%), and other nonfoliage items (4%); the langurs switched from being more folivorous in spring (93%) and summer (79%) to being more frugivorous in autumn (53%) and winter (56%). There was no correlation between the proportion of feeding records and the food availability in the most frequently consumed species, indicating that these langurs were selective feeders; there were significant correlations between consumption and abundance in both the entire set of 112 food species and the set of 86 infrequently consumed species, indicating that foods that are more available are eaten more frequently. It appeared that in the seasonal and disturbed habitat, feeding decisions and diet composition of the langur may be driven more by food availability, and less by animal's selectivity, than at other sites. The results indicate that François' langur copes with habitat alterations by broaden its dietary breadth; this has implications for the adaptive significance of dietary breadth, and has implications for future conservation strategies for species which exist in degraded habitats. Am. J. Primatol. 73:1176–1187, 2011. © 2011 Wiley Periodicals, Inc.
Optimization of polypropylene/clay nanocomposite processing using Box‐Behnken statistical design
Authors: Banerjee Saikat , Joshi Mangala , Ghosh Anup K.
Published: August 2011

A wide range of process parameters regulate the final morphology achieved in layered silicate based polymer nanocomposites. This study deals with the optimization of process variables to improve the matrix formulation. A three‐factor, three‐level Box‐Behnken design with compatibilizer concentration (X1), clay concentration (X2), and screw speed (X3) as the independent variables were selected for the study. The dependent variable was mechanical property of the final nanocomposites. Maleic anhydride grafted polypropylene (PP‐g‐MA) compatibilizer and organoclay (Cloisite 15A) was melt blended with polypropylene separately in a corotating twin screw extruder. The clay was modified with fluorescent dye Nile Blue A Perchlorate (NB) and the adsorbed dye content in the clay gallery was estimated by using UV‐spectrophotometric method. The Minitab‐15 software was used for analysis of the results obtained. Optimum compositions for better dispersion were achieved from contour plots and response surface methodology. It was supported by a unique fluorescence spectrophotometry along with transmission electron microscopy and X‐ray diffraction technique. An intensity ratio close to unity showed a better exfoliated morphology. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Dielectric behavior of alternating ethylene, propylene, and carbon monoxide co‐ and terpolymers via impedance spectroscopy
Authors: Jawad Saadi Abdul , Abu‐Surrah Adnan S. , Maghrabi Mufeed , Khattari Ziad
Published: August 2011

Dielectric behavior of alternating ethylene–carbon monoxide (ECO) and ethylene–carbon monoxide/propylene–carbon monoxide elastic terpolymer (EPEC‐48) (48% mole ratio of ECO) have been investigated by impedance spectroscopy. At intermediate frequencies, the co‐ and terpolymer samples display a relaxation peak with an activation energy of 1.40 and 1.12 eV, respectively, due to a rotational motion of the carbonyl groups in the relatively more polar ECO block. However, at low frequency, a relaxation peak was observed only in the EPEC‐48 terpolymer impedance and admittance spectra due to the rotational motion of the polar groups of propylene–carbon monoxide (PCO) block which is attached to ECO repeating units. In addition, it has been found that below 100°C the ECO material is highly resistive, and both dielectric constant and loss factor are dependent on frequency and temperature. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation and characterization of novel self cross‐linking fluorinated acrylic latex
Authors: Chen Lijun , Wu Fengqin
Published: August 2011

Self crosslinking fluorinated acrylic latex (SCLFAL) has been successfully prepared via starved seeded semibatch emulsion polymerization of butyl acrylate (BA), methyl methacrylate (MMA), 2‐(perfluoro‐(1,1‐bisisopropyl)‐2‐propenyl)oxyethyl methacrylate (POMA), and N‐methylolacrylamide (NMA). The resultant SCLFAL is characterized by Fourier transform infrared (FTIR) spectrometry and nuclear magnetic resonance (NMR). Influences of the added amount of NMA on the crosslinking degree, contact angle, particle size, and glass transition temperature (Tg) of the film are investigated. Results show that the crosslinking degree, contact angle, and Tg of the film can be improved when the moderate amount of NMA is introduced into the mixed monomers. However, the added amount of NMA has no marked effect on the particle size of SCLFAL. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Divinyl benzene cross‐linked HTPB‐based polyurethaneurea membranes for separation of p‐/o‐xylene mixtures by pervaporation
Authors: Gu Jin , Zhang Chun‐Fang , Bai Yun‐Xiang , Zhang Lin , Sun Yu‐Ping , Chen Huan‐Lin
Published: August 2011

Cross‐linked hydroxy terminated polybutadiene (HTPB)‐based polyurethaneurea (PU), HTPB‐divinyl benzene (DVB)‐PU, was synthesized by a three‐step polymerization process. It was first used as membrane material to separate p‐/o‐xylene mixtures by pervaporation (PV). The effects of the content of cross‐linker DVB, feed concentration, and operating temperature on the PV performance of HTPB‐DVB‐PU membranes were investigated. The membranes demonstrated p‐xylene permselectivity as well as high total flux. The introduction of DVB significantly enhanced the temperature resistance ability of the HTPB‐DVB‐PU membranes. With increasing DVB content, the separation factor increased while the total flux decreased a little. The highest separation factor reaches 2.01 and the total flux is 33 g/m2h with feed concentration of 10 wt % p‐xylene at 30°C. These PV performances with increasing DVB content were explained in terms of the view point of chemical compositions and physical structures of the HTPB‐DVB‐PU membranes. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synthesis, extraction, and anti‐bacterial studies of some new bis‐1,2,4‐triazole derivatives part I
Authors: Gumrukcuoglu Nurhan , Ugras Serpil , Ibrahim Ugras Halil , Cakir Umit
Published: August 2011

A series of new bis triazole Schiff base derivatives (4) were prepared in good yields by treatment of 4‐amino‐3,5‐diphenyl‐4H‐1,2,4‐triazole (3) with bisaldehydes (1). Schiff bases (4) were reduced with NaBH4 to afford the corresponding bisaminotriazoles (5). All the new compounds were characterized by IR, 1H NMR and 13C NMR spectral data. Their overall extraction (log Kex) constants for 1 : 1 (M : L) complexes and CHCl3/H2O systems were determined at 25 ± 0.1°C to investigate the relationship between structure and selectivity toward various metal cations. The extraction equilibrium constants were estimated using CHCl3/H2O membrane transfer with inductively coupled plasma‐atomic emission spectroscopy spectroscopy. The stability sequence of the triazole derivatives in CHCl3 for the metal cations was exhibited a characteristic preference order of extractability to metal ions [Fe(III) > Cu(II) > Pb(II) > Co(II) > Ni(II) > Mn(II) > Zn(II) > Mg(II) > Ca(II)]. The compounds were tested for anti‐microbial activity applying agar diffusion technique for 11 bacteria. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Surface modification of Kevlar by grafting carbon nanotubes
Authors: Chen Wei , Qian Xin‐Ming , He Xue‐Qiu , Liu Zhen‐Yi , Liu Ji‐Ping
Published: August 2011

A novel and efficient method was developed for surface‐modification of Kevlar fibers by multi‐wall carbon nanotubes (MWCNTs). Kevlar fibers were immersed in a solution mixed with Hexamethylene diisocyanate, 1,4‐diazabi‐cyclo [2,2,2] octane (DABCO), and toluene to introduce pendant amine groups before the COCl‐functionalized carbon nanotubes were chemically grafted onto the surface of modified fibers under ultrasonic condition. The characterization of resulting fiber involved in SEM, infrared spectroscopy, and tensile measurement. Results indicated over 20% of the fiber surface were coated by MWCNTs even after washing, which indicated a good adhesion. Furthermore, the mean value of tensile strength of Kevlar fiber was improved by 12% compared with original one. And the interlaminar shear strength (ILSS) of the fiber‐reinforced bismaleimides composite was increased by 30%. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Cellulose acetate/polysilsesquioxane composites: Thermal properties and morphological characterization by electron spectroscopy imaging
Authors: de Oliveira Junior Adair Rangel , Ferrarezi Márcia Maria Favaro , Yoshida Inez Valéria Pagotto , do Carmo Gonçalves Maria
Published: August 2011

Cellulose acetate (CA) composites using two types of silane coupling agents (methyltrimethoxysilane and phenyltriethoxysilane) were prepared through two methodologies: direct reaction between CA and the specific monomer and reaction of CA with oligomers, which were produced by prehydrolysis of the same monomers. The thermal behavior and morphology of the materials were studied. The composites showed thermal stability similar to pure CA, increase of residue content at 790°C and reduction in the glass transition temperature. Complementary microscopy techniques were applied to investigate the distribution of polysilsesquioxane in the CA matrix. Silicon mapping images showed the presence of domains with higher polysilsesquioxane concentration than the matrix and also the presence of silicon‐rich nanodomains dispersed throughout the matrix. Based on mapping characterization, a schematic representation of the CA/polysilsesquioxane composite morphology was proposed. The organosilane type and architecture influenced the thermal behavior and the morphology of these materials. The results suggest that the silane coupling agents could be used to produce CA films with a range of properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Glass fiber/wood flour modified high density polyethylene composites
Authors: Yang Changxing , Li Guan , Qi Rongrong , Huang Mark
Published: August 2011

Composites of high density polyethylene (HDPE) with the reinforcements of glass fiber (GF) and wood flour (WF) have been studied in this work. High‐density polyethylene‐grafted maleic hydride (HDPE‐g‐MAH) was used as a compatibilizer. In particular, the effect of GF, WF, and HDPE‐g‐MAH on the overall properties of GF/WF/HDPE composites (GWPCs in short form) was systematically studied. The results indicate that HDPE‐g‐MAH as a compatibilizer can effectively promote the interfacial adhesion between GF/WF and HDPE. By the incorporations of GF/WF, the heat deflection temperature can reach above 120°C, and the water absorption can be below 0.7%, also the tensile strength, flexural strength, and impact strength of GWPCs can surpass 55.2 Mpa, 69.4 Mpa, and 11.1 KJ/m2, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Preparation of poly(styrene‐co‐butyl acrylate)/montmorillonite nanocomposite by emulsion polymerization: Characterization and nanoscratch behavior
Authors: Moghbeli M.R. , Mehdizadeh N.
Published: August 2011

Organic–inorganic hybrid poly(styrene‐co‐butyl acrylate)/organically modified montmorillonite (PSBA/organo‐MMT) latex particles have been prepared by in situ emulsion polymerization. The effects of modifier variety and the level of organo‐MMT have been investigated on the basis of the characteristics and mechanical properties of the resulting hybrid emulsion polymers. Although the more hydrophilic intercalated organic modifiers increased the latex particle size, the hydrophobic ones decreased the particle size. A more heterogeneous copolymer chain intercalation was seen by widespread XRD reflection as the organo‐MMT (organoclay) level increases. The tapping mode atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to determine the dispersion state of organoclay particles inside the nanocomposite copolymer films. Dynamic mechanical thermal analysis (DMTA) showed that adding the organoclay to the copolymer decreased the maximum loss tangent (tanδ) value and caused the shift to a lower temperature. Interestingly, the incorporation of organoclay decreased the glass storage modulus of the copolymer, while increased the rubbery storage modulus to some extent. In addition, a standard indenter for the nanoscratching of copolymer nanocomposite films was used under low applied loads of 150 and 250 μN. The nanoscratch results showed that incorporation of a 3 wt % hydrophobic organoclay, e.g., Closite15A, in the copolymer matrix enhanced considerably the near‐surface hardness and grooving resistance of the nanocomposite film at room temperature. In fact, copolymer nanocomposite films with higher near‐surface hardness and tanδ curve broadening exhibited more nanoscratch resistance through a specific variety of viscoelastic deformation, which did not create a bigger groove. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Modeling of isochronal complex magnetic susceptibility of polymer–magnetic nanocomposites using fractional calculus
Authors: Garza‐Navarro M. A. , Reyes‐Melo M. E. , González‐González V. , Guerrero‐Salazar C. , Ortiz‐Méndez U.
Published: August 2011

In this work, we report on the application of fractional calculus to the modeling of the isochronal behavior of complex magnetic susceptibility obtained from polymer–magnetic nanocomposites composed of cobalt‐ferrite nanoparticles embedded into a chitosan matrix. From the isochronal measurements of real and imaginary parts of the complex magnetic susceptibility and temperature‐dependent static measurements, performed at different applied dc‐fields, it was observed that the spins' response is mainly leaded by three contributions, which are attributed to the intrinsic magnetic anisotropy of the particles, the surface‐to‐core spins exchange within particles and to the dipole‐dipole interactions among particles. Accounting these contributions, the proposed magnetic model was capable to describe, in very precise way, the experimental behavior of both, real and imaginary, parts of the complex magnetic susceptibility, at temperatures below to that related to the transition of the polymer–magnetic nanocomposite into the superparamagnetic regime. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
A library of tunable agarose carbomer‐based hydrogels for tissue engineering applications: The role of cross‐linkers
Authors: Rossi Filippo , Perale Giuseppe , Storti Giuseppe , Masi Maurizio
Published: August 2011

The role of the crosslinking agents was studied for a series of agarose–carbomer‐based hydrogels, specifically developed for tissue engineering applications, and was quantified using the most typical polycondensation parameter; the ratio between the reacting moieties, i.e., hydroxyl (A) and carboxyl (B) groups. Because of the bonds among hydrophilic groups, as A/B ratio was increased, the gel network showed higher compactness and less ability to swell. The role of crosslinkers was also further analyzed using environmental scanning electron microscopy (E/SEM) and rheological measurements. SEM analysis underlined the presence of different structures as well as the erosion due to the presence of cosolvents in hydrogel synthesis. Rheological measurements showed the dependence of crossover strain value and yield stress upon the ratio of hydroxyl/carboxyl groups and, generally, a clear pseudoplastic behavior. Such detailed characterizations were essential to investigate the design of an optimized formulation capable of being a proper hosting environment for glial cells, which were here used as they are a promising cell type in several central nervous system repair strategies. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci 123:2211–2221, 2012
Effect of shear stress extrusion intensity on plasticized corn flour structure: Proteins role and distribution
Authors: Jbilou Fouzia , Ayadi Farouk , Galland Sophie , Joly Catherine , Dole Patrice , Belard Laurent , Degraeve Pascal
Published: August 2011

Plasticized corn flour‐based materials were prepared by extrusion and injection molding. Extrusion of corn flour blends (75% wet basis (wb)—glycerol (5 or 10% wb)—water) was performed in a twin‐screw extruder with either one or three shearing zones. Native corn flour is mainly composed of corn starch granules surrounded by proteins layers. Therefore, the destructuration of corn flour by thermomechanical treatments was analyzed (i) by techniques essentially allowing to monitor corn starch amorphization (differential scanning calorimetry, X‐ray diffractometry, determination of water sorption isotherms, susceptibility to hydrolysis by amylolytic enzymes) (ii) and via proteins layers role and distribution observed by confocal scanning laser microscopy and comparing the susceptibility of corn starch to hydrolysis by amylolytic enzymes in the presence or not of a protease. Both corn starch granules amorphization and proteins dispersion and aggregation were more pronounced for materials extruded in a screw profile with three shearing zones. For materials extruded in a screw profile with one shearing zone, the amorphization of starch was higher in materials made with 5% wb glycerol, whereas the proteins dispersion and aggregation was more pronounced in materials made with 10% wb glycerol. A barrier role of proteins to hydrolysis of corn starch by amylolytic enzymes was demonstrated and discussed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Polyoxymethylene‐homopolymer/hydroxyapatite nanocomposites for biomedical applications
Authors: Pielichowska Kinga
Published: August 2011

In this article, new polyoxymethylene (POM)/hydroxyapatite (HAp) nanocomposites for bone long‐term implants have been obtained and characterized by using FTIR, WAXD, SEM, TG, DSC, tensile tests, and in vitro evaluation. Characteristic bands both for extended chain crystals (ECC) and folded chain crystals (FCC) were observed in FTIR profiles for both pure POM and POM in POM/HAp nanocomposites. From WAXD analysis it has been found that the addition of HAp does not change the hexagonal system of POM in POM/HAp nanocomposites. Moreover, degree of crystallinity of POM increases with an increase of HAp content up to 1.0% and next decreases with an increase HAp content. It indicates that HAp nanoparticles up to 1.0% content act as effective nucleating sites. Mechanical tests revealed that Young's modulus increases, whereby, elongation at break and tensile strength decrease with increasing hydroxyapatite concentration. Results of in vitro investigations show that an increase of HAp content in POM nanocomposites facilitates formation of apatite layer on the sample surface and improves in vitro stability POM/HAp nanocomposites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Rheological evaluation of electron beam irradiated polypropylene in the presence of a multifunctional monomer and polybutene resin
Authors: Zarch F. Shamsoddini , Jahani Y. , Haghighi M. Nekoomanesh , Morshedian J.
Published: August 2011

In this research, the rheological properties of electron beam irradiated polypropylene homo polymer (PP) containing Polybutene (PB) resin and Trimethylol Propane Trimethacrylate multifunctional monomer is studied. The effect of PB resin in inducing long chain branches on the PP backbone are evaluated by various viscoelastic parameters. The zero shear viscosity (η0) of samples containing 5% PB resin considerably decreased to 5500 Pa s, from η0 = 11,500 Pa s, which indicates the plasticizing effect of PB resin on the ease of movement of PP macromolecules. It is found that the presence of PB resin enhanced the branching by facilitating the movement of PP macromolecules in solid state and increasing the recombination efficiency of PP macro radicals. The mobilizing effect of PB resin also reduced chain scission and degradation of PP resin which is traced by shifting the cross over frequency. The PB free radicals formed during the irradiation process can bound to PP free radicals and suppress the degradation process. The evaluation of zero shear viscosity ratios and crossover point ratios of irradiated samples to un‐irradiated ones confirmed that using small amount of PB resin increase branching efficiency, which is the evidence of mobilizing effect of PB resin. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Endogenous prostaglandin E2 inhibits aberrant overgrowth of rheumatoid synovial tissue and the development of osteoclast activity through EP4 receptor
Authors: Shibata‐Nozaki Toshiko , Ito Hiroshi , Mitomi Hirofumi , Akaogi Jun , Komagata Tatsuya , Kanaji Toshiya , Maruyama Takayuki , Mori Toshihito , Nomoto So , Ozaki Shoichi , Yamada Hidehiro
Published: August 2011

Objective

We recently developed an ex vivo cellular model of pannus, the aberrant overgrowth of human synovial tissue. This study was undertaken to use that model to investigate the role of prostaglandin E2 (PGE2) and its receptor subtypes in the development of pannus growth and osteoclast activity in rheumatoid arthritis (RA).

Methods

Inflammatory cells that infiltrated pannus from patients with RA were collected without enzyme digestion and designated synovial tissue–derived inflammatory cells. Their single‐cell suspensions were cultured in medium alone to observe an aberrant overgrowth of inflammatory tissue in vitro. Levels of cytokines produced in culture supernatants were measured using enzyme‐linked immunosorbent assay kits. Osteoclast activity was assessed by the development of resorption pits in calcium phosphate–coated slides.

Results

Primary culture of the synovial tissue–derived inflammatory cells resulted in spontaneous reconstruction of inflammatory tissue in vitro within 4 weeks, during which tumor necrosis factor α, PGE2, macrophage colony‐stimulating factor, and matrix metalloproteinase 9 were produced in the supernatant. This aberrant overgrowth was inhibited by antirheumatic drugs including methotrexate and infliximab. On calcium phosphate–coated slides, synovial tissue–derived inflammatory cells showed numerous resorption pits. In the presence of inhibitors of endogenous prostanoid production such as indomethacin and NS398, exogenous PGE1 and EP4‐specific agonists significantly inhibited all these activities of synovial tissue–derived inflammatory cells in a dose‐dependent manner. Addition of indomethacin, NS398, or EP4‐specific antagonist resulted in the enhancement of these cells' activities. EP2‐specific agonist had a partial effect, while EP1‐ and EP3‐specific agonists had no significant effects.

Conclusion

These results suggest that endogenous PGE2 produced in rheumatoid synovium negatively regulates aberrant synovial overgrowth and the development of osteoclast activity via EP4.
Analysis of covariance with pre‐treatment measurements in randomized trials: Comparison of equal and unequal slopes
Authors: Funatogawa Ikuko , Funatogawa Takashi
Published: August 2011

In randomized trials, an analysis of covariance (ANCOVA) is often used to analyze post‐treatment measurements with pre‐treatment measurements as a covariate to compare two treatment groups. Random allocation guarantees only equal variances of pre‐treatment measurements. We hence consider data with unequal covariances and variances of post‐treatment measurements without assuming normality. Recently, we showed that the actual type I error rate of the usual ANCOVA assuming equal slopes and equal residual variances is asymptotically at a nominal level under equal sample sizes, and that of the ANCOVA with unequal variances is asymptotically at a nominal level, even under unequal sample sizes. In this paper, we investigated the asymptotic properties of the ANCOVA with unequal slopes for such data. The estimators of the treatment effect at the observed mean are identical between equal and unequal variance assumptions, and these are asymptotically normal estimators for the treatment effect at the true mean. However, the variances of these estimators based on standard formulas are biased, and the actual type I error rates are not at a nominal level, irrespective of variance assumptions. In equal sample sizes, the efficiency of the usual ANCOVA assuming equal slopes and equal variances is asymptotically the same as those of the ANCOVA with unequal slopes and higher than that of the ANCOVA with equal slopes and unequal variances. Therefore, the use of the usual ANCOVA is appropriate in equal sample sizes.
Kinetic and growth parameters of Arthrospira (Spirulina) platensis cultivated in tubular photobioreactor under different cell circulation systems
Authors: Ferreira Lívia S. , Rodrigues Mayla S. , Converti Attilio , Sato Sunao , Carvalho João C.M.
Published: August 2011

Arthrospira platensis was cultivated in tubular photobioreactor in order to evaluate growth and biomass production at variable photosynthetic photon flux density (PPFD = 60, 120, and 240 µmol photons m−2 s−1) and employing three different systems for cell circulation, specifically an airlift, a motor‐driven pumping and a pressurized system. The influence of these two independents variables on the maximum cell concentration (Xm), cell productivity (Px), nitrogen‐to‐cell conversion factor (YX/N), photosynthetic efficiency (PE), and biomass composition (total lipids and proteins), taken as responses, was evaluated by analysis of variance. The statistical analysis revealed that the best combination of responses' mean values (Xm = 4,055 mg L−1, Px = 406 mg L−1 day−1, YX/N = 5.07 mg mg−1, total lipids = 8.94%, total proteins = 30.3%, PE = 2.04%) was obtained at PPFD = 120 µmol photons m−2 s−1; therefore, this light intensity should be considered as the most well‐suited for A. platensis cultivation in this photobioreactor configuration. The airlift system did not exert any significant positive statistical influence on the responses, which suggests that this traditional cell circulation system could successfully be substituted by the others tested in this work. Biotechnol. Bioeng. 2012; 109:444–450. © 2011 Wiley Periodicals, Inc.
Determination of thyroid hormones and their metabolites in tissue using SPE UPLC‐tandem MS
Authors: Ackermans M. T. , Kettelarij‐Haas Y. , Boelen A. , Endert E.
Published: August 2011

A solid‐phase liquid chromatography tandem mass spectrometry (SPE LC‐MS/MS) method was developed to determine thyroid hormones and their metabolites in tissue samples. The separation was achieved using reversed‐phase ultra‐performance liquid chromatography (UPLC); the mass spectrometric detection was achieved by positive electrospray ionization and multiple reaction monitoring. Prior to the UPLC separation a sample cleanup with a cation exchange was performed. 13 C6 labeled internal standards were used for the thyroid hormones and their metabolites. The method was linear over a range from 0.23 to 90 nmol/L for thyroxine and from 0.23 to 9 nmol/L for the metabolites. The lower limit of quantification ranged from 0.98 to 1.73 pg on column. Intra‐ and total assay variation were <10 and <15%, respectively. This method enables us to link thyroid hormone tissue concentrations to local iodothyronine deiodinase expressions, which will enhance our understanding of the regulation of thyroid hormone metabolism on the tissue level. Copyright © 2011 John Wiley & Sons, Ltd.
Quantitative determination of uridine in rabbit plasma and urine by liquid chromatography coupled to a tandem mass spectrometry
Authors: Kang Wonku
Published: August 2011

Recently a pyrimidine nucleoside, uridine, has been show to have a protective effect on cultured human corneal epithelial cells, and on dry eye animal model and patients. In this study, we introduce a sensitive liquid chromatography/tandem mass spectrometry method for the determination of uridine in rabbit plasma and urine. After protein precipitation with methanol including methaqualone (internal standard), the analyte was chromatographed on a reversed‐phase column with a mobile phase of 0.1% formic acid aqueous solution and methanol (1:4, v/v). The accuracy and precision of the assay were in accordance with Food and Drug Administration regulations for the validation of bioanalytical methods. This method was used to measure the concentrations of uridine in plasma and urine after a single oral administration of 450 mg/kg uridine in rabbits. Copyright © 2011 John Wiley & Sons, Ltd.
The Role of Warning Behaviors in Threat Assessment: An Exploration and Suggested Typology
Authors: Reid Meloy J. , Hoffmann Jens , Guldimann Angela , James David
Published: August 2011

The concept of warning behaviors offers an additional perspective in threat assessment. Warning behaviors are acts which constitute evidence of increasing or accelerating risk. They are acute, dynamic, and particularly toxic changes in patterns of behavior which may aid in structuring a professional's judgment that an individual of concern now poses a threat – whether the actual target has been identified or not. They require an operational response. A typology of eight warning behaviors for assessing the threat of intended violence is proposed: pathway, fixation, identification, novel aggression, energy burst, leakage, directly communicated threat, and last resort warning behaviors. Previous research on risk factors associated with such warning behaviors is reviewed, and examples of each warning behavior from various intended violence cases are presented, including public figure assassination, adolescent and adult mass murder, corporate celebrity stalking, and both domestic and foreign acts of terrorism. Practical applications and future research into warning behaviors are suggested. Copyright © 2011 John Wiley & Sons, Ltd.
Computational fluid dynamics modeling of mass transfer behavior in a bioreactor for hairy root culture. I. Model development and experimental validation
Authors: Liu Rui , Sun Wei , Liu Chun‐Zhao
Published: August 2011

A two‐dimensional axisymmetric computational fluid dynamics (CFD) model based on a porous media model and a discrete population balance model was established to investigate the hydrodynamics and mass transfer behavior in an airlift bioreactor for hairy root culture. During the hairy root culture of Echinacea purpurea, liquid and gas velocity, gas holdup, mass transfer rate, as well as oxygen concentration distribution in the airlift bioreactor were simulated by this CFD model. Simulative results indicated that liquid flow and turbulence played a dominant role in oxygen mass transfer in the growth domain of the hairy root culture. The dissolved oxygen concentration in the hairy root clump increased from the bottom to the top of the bioreactor cultured with the hairy roots, which was verified by the experimental detection of dissolved oxygen concentration in the hairy root clump. This methodology provided insight understanding on the complex system of hairy root culture and will help to eventually guide the bioreactor design and process intensification of large‐scale hairy root culture. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Review of Computational fluid dynamics applications in biotechnology processes
Authors: Sharma C. , Malhotra D. , Rathore A. S.
Published: August 2011

Computational fluid dynamics (CFD) is well established as a tool of choice for solving problems that involve one or more of the following phenomena: flow of fluids, heat transfer, mass transfer, and chemical reaction. Unit operations that are commonly utilized in biotechnology processes are often complex and as such would greatly benefit from application of CFD. The thirst for deeper process and product understanding that has arisen out of initiatives such as quality by design provides further impetus toward usefulness of CFD for problems that may otherwise require extensive experimentation. Not surprisingly, there has been increasing interest in applying CFD toward a variety of applications in biotechnology processing in the last decade. In this article, we will review applications in the major unit operations involved with processing of biotechnology products. These include fermentation, centrifugation, chromatography, ultrafiltration, microfiltration, and freeze drying. We feel that the future applications of CFD in biotechnology processing will focus on establishing CFD as a tool of choice for providing process understanding that can be then used to guide more efficient and effective experimentation. This article puts special emphasis on the work done in the last 10 years. © 2011 American Institute of Chemical Engineers Biotechnol. Prog., 2011
Catalytic Properties of Silver Vanadium Phosphates in n‐Butane Oxidation – Considerations on the Impact of the [VxOy] Substructure
Authors: Karpov Andrey , Dobner Cornelia‐Katharina , Glaum Robert , Schunk Stephan Andreas , Rosowski Frank
Published: August 2011

Catalysts based on silver vanadium phosphates with a general chemical formula Ag2VPxOd (1 ≤ x ≤ 2; 6 ≤ d ≤ 8) have been prepared and tested in gas phase oxidation of n‐butane. This general chemical formula comprises the two known phosphates Ag2(VVO2)PO4 (x = 1; d = 6) and Ag2(VIVO)P2O7 (x = 2; d = 8) and one novel compound with an approximate composition Ag2VIV,VP1.6O7+δ (0 ≤ δ ≤ 0.5). Among the prepared compounds, Ag2(VVO2)PO4 shows the highest activity while Ag2(VIVO)P2O7 is completely inactive. The novel phase Ag2VIV,VP1.6O7+δ (0 ≤ δ ≤ 0.5) is the only compound with selectivity to maleic anhydride. A structure‐property relationship for the prepared catalysts is discussed.
Performance evaluation of an IEEE 802.11g mesh network with multiradio nodes
Authors: Bencini Luca , Fantacci Romano
Published: August 2011

Wireless mesh networks are usually formed by self‐organized nodes and characterized by high reliability and modularity, low‐cost deployment, and easiness of reconfigurability. In order to improve wireless mesh network performance, several approaches have been recently proposed. Among them, one promising solution seems to be the multiradio interface approach where nodes forming the mesh network are equipped with more than one radio interface. The aim of this paper is to provide an IEEE 802.11 distributed coordination function analytical model to study the behavior of single‐hop multi‐interface mesh networks in which nodes use a uniform random interface selection strategy to identify the radio interface to be used. The accuracy of the proposed analytical approach is validated by comparing analytical predictions with simulation results under actual conditions. Copyright © 2011 John Wiley & Sons, Ltd.
The development of whisker control in rats in relation to locomotion
Authors: Grant Robyn A. , Mitchinson Ben , Prescott Tony J.
Published: August 2011

Adult rats sweep their large facial whiskers (macrovibrissae) back and forth in a rhythmic pattern known as “whisking”. Here we examine how these whisker movements develop in relation to other aspects of exploratory behavior, particularly locomotion. We analyzed 963 high‐speed video recordings of neonatal rats, from P1 (Post‐natal day 1) to P21, and measured the emergence of whisker control and of head, body, and limb movements. Prior to P11, whisker movements were largely limited to unilateral retractions accompanying head turns. Between P11 and P13 bilateral whisking emerged alongside increased forward locomotion and improved control of the head. Contact‐induced modulations of whisking symmetry, synchrony, and whisker spread emerge shortly thereafter but continue to develop until at least P18, coinciding with the emergence of adult‐like locomotion patterns such as rearing. Overall, whisking develops alongside increasing locomotor competence indicating that active vibrissal sensing plays an important role in the exploratory behavior of the developing animal. © 2011 Wiley Periodicals, Inc. Dev Psychobiol 54:151‐168, 2012.
Paradigms, Policy and Governance: The Politics of Energy Regulation in the UK Post‐2000
Authors: Fudge Shane , Peters Michael , Mulugetta Yacob , Jackson Tim
Published: August 2011

This paper considers the debate around energy policy and government regulation in the UK, considering Helm's idea that the current period can be conceptualized as a distinct ideological paradigm in the same way that both nationalization and privatization were enmeshed within particular political and economic goals. As he reasons, the first paradigm was based on nationalization and had the purpose of bringing vital services under public ownership and the second paradigm was constructed around the premises of liberalization and privatization. Drawing on the work of Mitchell, the paper explores Helm's observations on the link between ‘paradigms and policy’ to suggest that the failings of a market‐based approach to addressing climate change and energy security argue that a more radical shift in direction and thinking is needed. In particular, it is argued that the UK Government's more recent targets on reducing carbon emissions suggest the need for an energy policy agenda that is more clearly de‐linked from the current emphasis on market solutions and associated political thinking. It is argued that such a transition in policy would need to revolve around Kuhn's pre‐conditions of a ‘gestalt switch’ – as indicated in both previous UK regulatory approaches to energy. We suggest that, in much the same way as the dominant scientific consensus structured Kuhn's original conception of a paradigm, such a shift in policy will involve a ‘gestalt switch’, and a politically led shift away from the influence of thinking which currently remains rooted in previous infrastructural and ideological legacies. Copyright © 2011 John Wiley & Sons, Ltd and ERP Environment.
The Drivers and Outcomes of the Clean Development Mechanism in China
Authors: Thomas Sebastian , Dargusch Paul , Griffiths Andrew
Published: August 2011

The Clean Development Mechanism (CDM) is a flexible market mechanism intended to reduce greenhouse emissions and promote sustainable development. China hosts a third of all registered CDM projects, and generates two‐thirds of all certified emissions reductions. Understanding the political economy of the CDM in China is therefore of critical importance in determining whether the CDM is an effective instrument to promote sustainable development and mitigate climate change. This paper discusses the nature and dynamics of CDM project development in China by analysing the 579 registered CDM projects operating in China as of 1 July 2009. The predominant activities are hydroelectric and wind power projects, with foreign involvement largely by European firms specializing in emerging carbon markets. The sustainability outcomes of projects in China are primarily economic, with environmental benefits largely restricted to cleaner production. The results suggest that the CDM is largely being employed as an ancillary device to attract foreign investment and further China's existing development agenda. We argue that the these results indicate the need for further reform of the CDM to achieve desired outcomes, and that China's approach to the design of integrated policy portfolios might be an example of how to achieve this. Copyright © 2011 John Wiley & Sons, Ltd and ERP Environment.