bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization of cationic starch: An efficient flocculating agent
Authors: Pal Sagar , Mal D. , Singh R. P. 
Published: February 2008

AbstractStarch is a known carbohydrate in which, regardless of its origin, two polysaccharides are found namely amylose and amylopectin. By insertion of a cationic moiety to the backbone of starch, a modified cationic starch can be developed which can be used as flocculant. Various grades of cationic starches were developed to optimize the best performing flocculant. The base polysaccharide, starch and the best performing cationic starch i.e., Cat St3 (which have been confirmed from flocculation characteristics and intrinsic viscosity measurement) have been characterized by various characterization techniques such as determination of molecular weight, elemental analysis, FTIR spectroscopy, intrinsic viscosity measurement, thermal analysis, etc. From the characterization, it could be concluded that there was a substantial incorporation of cationic moiety onto the backbone of starch. The flocculation efficacy of these cationized starches was compared with each other and with some of the commercial flocculants available in national and international market in manganese ore suspensions. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Molecular weight distribution broadening of polypropylene by periodic switching of hydrogen and catalyst additions
Authors: Ali M. Al‐Haj , Stroomer J. , Betlem B. , Weickert G. , Roffel B. 
Published: February 2008

AbstractThis study presents a feasibility study of the broadening of the polypropylene molecular weight distribution produced using a multisite Ziegler‐Natta catalyst in a continuous liquid‐pool polymerization reactor. The broadening is achieved by operating the reactor under periodic forcing of both hydrogen and catalyst feed flows. Model‐based dynamic optimization is used to determine the cycle period and peak width for these inputs. Through simulation it is shown that limited widening (∼ 30%) of the molecular weight distribution can be achieved in case of a limited removal of hydrogen from the reactor. The results also show that the forced removal of hydrogen from the reactor could potentially double the polydispersity index of the produced polymer. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Improvement of the conductivity, electroactivity, and redoxability of polythiophene by electropolymerization of thiophene in the presence of catalytic amount of 1‐(2‐pyrrolyl)‐2‐(2‐thienyl) ethylene (PTE)
Authors: Kiani G. R. , Arsalani N. , Hosseini M. G. , Entezami A. A. 
Published: February 2008

AbstractThe electropolymerization of thiophene in the presence of 1‐(2‐pyrrolyl)‐2‐(2‐thienyl) ethylene (PTE) was investigated. PTE was synthesized via Wittig reaction and by the addition of catalytic amount of PTE during the electropolymerization of thiophene, the conditions of electropolymerization of thiophene were modified. The cyclic votammograms of polythiophenes (PThs) in different conditions were obtained. The analysis of cyclic votammograms of PThs shows a considerable increase in the electroactivity and redoxability when the electropolymerization of thiophene in the presence of catalytic amount of PTE was performed. The presence of PTE during electropolymerization of thiophene leads to an increase in the rate of polymerization too. The cyclic voltammetry (CV) measurement of electron transfer ferro/ferricyanide redox system on different modified glassy carbon (GC) electrode has shown that the rate of charge transfer for PTh in the presence of PTE increased in comparison to pure PTh. The conductivity of obtained polymers was determined by electrochemical impedance spectroscopy (EIS) technique in 3.5% (w/v) NaCl solutions. The Zview(II) software was applied to the EIS to estimate the parameters of the proposed equivalent circuit, based on a physical model for the electrochemical behavior of coatings on GC. The Rct value obtained for PTh is 7667 Ω cm2. This value decreases in the presence of PTE to 4437 Ω cm2. Thus, the new film has more conductivity. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Structure and properties of tailor‐made poly(ethyl acrylate)/clay nanocomposites prepared by in situ atom transfer radical polymerization
Authors: Datta Haimanti , Singha Nikhil K. , Bhowmick Anil K. 
Published: February 2008

AbstractAn in‐depth study was carried out on the structure and properties of a series of poly(ethyl acrylate)/clay nanocomposites prepared by in situ atom transfer radical polymerization (PNCIs) with well‐defined molecular weights and narrow molecular weight distributions. Wide‐angle X‐ray diffraction and transmission electron microscopy studies revealed an exfoliated clay morphology, whereas conventional solution blending generated an intercalated structure. The storage moduli of the PNCIs showed a moderate increase over that of the neat polymer [poly(ethyl acrylate)]. The sample containing 4 wt % clay (PNCI4, where the number following PNCI indicates the weight percentage of clay) exhibited the highest improvement (31.9% at 25°C). In PNCIs, the β‐transition temperature showed a remarkable decrease (by 175% in PNCI4) along with a shift toward higher temperatures. This indicated the probability of the anchoring of the OH group of the clay layers to the >CO group of the pendant acrylate moiety, which was also confirmed by Fourier transform infrared analysis. Rheological measurements indicated a significant increase in the shear viscosity [by 9% in PNCI2, 15% in PNCI4, and 6% in the poly(ethyl acrylate)/clay nanocomposite with 2 wt % clay prepared by solution blending]. The PNCIs registered enhanced thermal stability, as indicated by the shift in the peak maximum temperature (388 and 392°C for the neat polymer and PNCI4, respectively) and a decrease in the rate of degradation (by 3.5% in PNCI2, 10.2% in PNCI4, and 49.3% in PNCI6). © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Microwave heating of poly(ethylene terephthalate) bottle preforms used in the thermoforming process
Authors: Lebaudy Philippe , Estel Lionel , Ledoux Alain 
Published: February 2008

AbstractThermoforming (free blowing) of poly(ethylene terephthalate) preforms was successfully and quickly performed in a rotating system designed for dielectric hysteresis heating. Temperature profile modeling was carried out with the amorphous poly(ethylene terephthalate) permittivity at different temperatures. The Maxwell and heat equations were used to determine the best profile and power tuning. The determination of the theoretical boundary conditions was accomplished by the adjustment of the numerical transient external surface wall temperature with experimental infrared pyrometry results. In comparison with infrared, microwaves allowed high power density absorption inside the perform wall without a dramatic temperature gradient. Consequently, the heat blowing stage could be accelerated, and the process took at least 5 times less energy than infrared heating. Industrial applications involve the integration of the molding step and the design of the overall process. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Chelation properties of poly(β‐diketone) polymer and its oxime toward heavy metal ions
Authors: Hammad Eman M. , Mubarak Mohammad S. 
Published: February 2008

AbstractThe chelation behavior of poly(β‐diketone), polymer I, and poly(β‐diketone) oxime, polymer II, toward the divalent metal ions, Cu2+, Zn2+, Ni2+, and Cd2+, and the trivalent lanthanide metal ions, La3+, Nd3+, Sm3+, Gd3+, and Tb3+ was investigated by a batch equilibration technique as a function of contact time, pH, and counter ion. Polymer II exhibited improved chelation characteristics toward lanthanide metal ions in comparison with polymer I and the metal‐ion uptake follows the order Tb3+ ≈ Gd3+ ≈ Sm3+ > Nd3+ ≈ La3+. On the other hand, polymer I showed relatively higher capacity than polymer II, toward the investigated divalent metal ions, where the metal‐ion uptake follows the order Cu2+ > Cd2+ ≈ Zn2+ > Ni2+. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Graft copolymerization of sodium acrylate onto organophilic montmorillonites initiated by potassium diperiodatonickelate (IV) and application of graft copolymer in water‐superabsorbent
Authors: Deng Kui Lin , Zheng Xiang Yang , Liu Jing , Zhang Ya Qin , Jia Na , Tian Hua , Liu Ying Hai 
Published: February 2008

AbstractThe graft copolymerization of sodium acrylate (SA) onto organophilic montmorillonites (OMMT) initiated by redox reaction of potassium diperiodatonickelate (IV) [Ni(IV)] with reactive groups on OMMT substrate was studied in alkaline medium. The grafting parameters have been investigated as a function of the ratio of monomer to OMMT, the concentration of initiator, temperature, and pH value. The structure of the graft copolymer (OMMT‐g‐PSA) was systematically characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and scanning electron microscope (SEM). It was found that [Ni(IV)] belongs to a highly efficient initiator for graft copolymerization of SA onto OMMT via the redox iniation (grafting efficiency > 95%). Furthermore, the experimental results also showed that the graft copolymer gels synthesized under optimal condition exhibited a maximum water absorbency of 1104 g/g in distilled water and 111 g/g in 0.2 wt % NaCl solution, respectively, and its water retention ability is more than 91% after centrifugal separation for 2 h. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Viscoelasticity of epoxy resin/silica hybrid materials with an acid anhydride curing agent
Authors: Araki Wakako , Wada Shogo , Adachi Tadaharu 
Published: February 2008

AbstractThe viscoelasticity of epoxy resin/silica hybrid materials manufactured by the sol–gel process with an acid anhydride curing agent was investigated in terms of morphology. Transmission microscopy observations demonstrated that all the prepared hybrid samples had a two‐phased structure consisting of an epoxy phase and a silica phase. The formed silica had either nanosized particles or coarse domains, depending on the catalyst for the sol–gel process. Raman spectroscopy analysis showed that the formed silica had features typical of sol–gel derived silica glass and that the ring‐opening reactions of the epoxy groups developed in the hybrid samples and in the neat epoxy samples. In dynamic mechanical thermal analysis, there were two transition temperatures due to epoxy chain mobility and epoxy network relaxation, through which the moduli changed by nearly 3 orders of magnitude. The hybridization disturbed epoxy network formation but also reinforced the epoxy network with the formed silica, which was characterized by the activation energy of the network relaxation; therefore, the modulus of the rubbery state was correlated to the activation energy. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008
Knee Posture Predicted from Subchondral Apparent Density in the Distal Femur: An Experimental Validation
Authors: Polk John D. , Blumenfeld J. , Ahluwalia D. 
Published: February 2008

AbstractSpatial patterning in the apparent density of subchondral bone can be used to discriminate between species that differ in their joint loading conditions. This study provides an experimental test of two hypotheses that relate aspects of subchondral apparent density patterns to joint loading conditions. First, the region of maximum subchondral apparent density (RMD) will correspond to differences in joint posture at the time of peak locomotor loads; and second, differences in maximum density between individuals will correspond to differences in exercise level. These hypotheses were tested using three age‐matched samples of juvenile sheep. Two groups of five sheep were exercised, at moderate walking speeds, twice daily for 45 days on a treadmill with either a 0% or 15% grade. The remaining sheep were not exercised. Sheep walking on the inclined treadmill used more flexed knee postures than those in the level walking group at the time of peak vertical ground reaction forces. Kinematic measurements of knee posture were compared with knee postures estimated from the spatial position of the RMD on the medial femoral condyle. Our results show that the difference in the position of the RMD between the incline and level walking groups corresponded to the difference in knee postures obtained kinematically; however, exercised and nonexercised sheep did not differ in the magnitude of apparent density. These results suggest that patterns of subchondral apparent density are good indicators of the experimental modifications in joint posture during locomotion and may, therefore, be used to investigate differences between species in habitual joint loading. Anat Rec, 291:293–302, 2008. © 2008 Wiley‐Liss, Inc.
Volumetric Neuroimaging of the Atlantic White‐Sided Dolphin (Lagenorhynchus acutus) Brain from in situ Magnetic Resonance Images
Authors: Montie Eric W. , Schneider Gerald , Ketten Darlene R. , Marino Lori , Touhey Katie E. , Hahn Mark E. 
Published: February 2008

AbstractThe structure and development of the brain are extremely difficult to study in free‐ranging marine mammals. Here, we report measurements of total white matter (WM), total gray matter (GM), cerebellum (WM and GM), hippocampus, and corpus callosum made from magnetic resonance (MR) images of fresh, postmortem brains of the Atlantic white‐sided dolphin (Lagenorhynchus acutus) imaged in situ (i.e., the brain intact within the skull, with the head still attached to the body). WM:GM volume ratios of the entire brain increased from fetus to adult, illustrating the increase in myelination during ontogeny. The cerebellum (WM and GM combined) of subadult and adult dolphins ranged from 13.8 to 15.0% of total brain size, much larger than that of primates. The corpus callosum mid‐sagittal area to brain mass ratios (CCA/BM) ranged from 0.088 to 0.137, smaller than in most mammals. Dolphin hippocampal volumes were smaller than those of carnivores, ungulates, and humans, consistent with previous qualitative results assessed from histological studies of the bottlenose dolphin brain. These quantitative measurements of white matter, gray matter, corpus callosum, and hippocampus are the first to be determined from MR images for any cetacean species. We establish here an approach for accurately determining the size of brain structures from in situ MR images of stranded, dead dolphins. This approach can be used not only for comparative and developmental studies of marine mammal brains but also for investigation of the potential impacts of natural and anthropogenic chemicals on neurodevelopment and neuroanatomy in exposed marine mammal populations. Anat Rec, 291:263–282, 2008. © 2008 Wiley‐Liss, Inc.
Digit Ratios in Green Anolis Lizards (Anolis carolinensis)
Authors: Lombardo Michael P. , Thorpe Patrick A. 
Published: February 2008

AbstractThe development of tetrapod digits is directed by the Homeobox (Hox) genes. The expression of Hox genes is influenced by exposure to endogenous sex steroids during development so that prenatal exposure to estrogens and androgens positively influences the lengths of digits 2 (2D) and 4 (4D), respectively. Because of this, Manning (2002) predicted that male tetrapods should have smaller 2D:4D than that of females because males are exposed to higher levels of androgens during development. We measured digits in green anolis lizards (Anolis carolinensis) to (a) test Manning's prediction; (b) compare our results with those of other studies of digit ratios in reptiles and birds to test the phylogenetic constraint hypothesis, which argues that the digit ratios of reptiles and birds should be more similar to each other than either taxa is to mammals because the patterns have been conserved in living diapsids; and (c) compare our results with those of another study of digit ratio in anoles (Chang et al., 2006). We did not detect evidence of sexual dimorphism in 2D:4D. Our results did not support either Manning's prediction or the phylogenetic constraint hypothesis. Furthermore, our results did not match those found in Chang et al. (2006), suggesting that digit ratios in anolis lizards may not be reliable indicators of prenatal exposure to hormones. Anat Rec, 291:433–440, 2008. © 2008 Wiley‐Liss, Inc.
Immunohistochemical and Morphometric Study of Pituitary Pars Distalis Thyrotrophs of Male Viscacha (Lagostomus maximus maximus): Seasonal Variations and Effect of Melatonin and Castration
Authors: Filippa Verónica , Mohamed Fabian 
Published: February 2008

AbstractThe physiology and behavior of viscacha vary along the year according to the modifications of environmental signals such as the photoperiod length, temperature, rainfall pattern, food composition, and social interactions. The pituitary pars distalis thyrotrophs (TSH cells) of male viscacha were immunohistochemically identified, and the morphometric parameters: percentage of immunopositive area (% IA), cell percentage in pars distalis (% PDC), number of cells per reference area (no. cells/RA), and major cellular and nuclear diameters were analyzed. Three different groups of adult male viscachas were used: (1) captured in their natural habitat during the year, (2) melatonin‐administered, and (3) castrated. The thyrotrophs were localized in the ventromedial sector, mainly in the pars distalis cephalic extreme. They were oval or pyramidal in shape, and their immunostaining intensity was heterogeneous. The % IA, % PDC, and no. cells/RA exhibited a significant decrease in June–July (winter, gonadal regression period) in relation to February–March (summer–early autumn, reproductive period), and they were recovered in August–September (later winter–early spring, gonadal recovery period). No morphometric variations of TSH cells were observed in melatonin‐treated animals, whereas a decrease of the % IA, % PDC, and no. cells/RA was observed in castrated animals in relation to the intact animals. Our results show TSH cell morphometric variations during the year in agreement with the animal's different physiological conditions during the reproductive cycle, and probably in response to the environmental signals changes. Melatonin does not have a direct effect on the TSH cells. However, castration modifies some thyrotroph morphometric parameters, reinforcing the hypothesis that androgens affect the cells activity. Anat Rec, 291:400–409, 2008. © 2008 Wiley‐Liss, Inc.
A Solid‐State Fluorescent Host System with a 21‐Helical Column Consisting of Chiral (1R,2S)‐2‐Amino‐1,2‐diphenylethanol and Fluorescent 1‐Pyrenecarboxylic Acid
Authors: Imai Yoshitane , Murata Katuzo , Kawaguchi Kakuhiro , Sato Tomohiro , Tajima Nobuo , Kuroda Reiko , Matsubara Yoshio 
Published: February 2008

AbstractA solid‐state fluorescent host system was created by self‐assembly of a 21‐helical columnar organic fluorophore composed of (1R,2S)‐2‐amino‐1,2‐diphenylethanol and fluorescent 1‐pyrenecarboxylic acid. This host system has a characteristic 21‐helical columnar hydrogen‐ and ionic‐bonded network. Channel‐like cavities are formed by self‐assembly of this column, and various guest molecules can be included by tuning the packing of this column. Moreover, the solid‐state fluorescence of this host system can change according to the included guest molecules. This occurs because of the change in the relative arrangement of the pyrene rings as they adjust to the tuning of the packing of the shared 21‐helical column, according to the size of the included guest molecules. Therefore, this host system can recognize slight differences in molecular size and shape.
Synthesis of syn‐2,4‐Dimercapto‐1,3,2,4‐dithiadigermetane and Its Application to Ge2PdS4 Cluster Synthesis
Authors: Matsumoto Tsuyoshi , Matsui Yosuke , Ito Mikinao , Tatsumi Kazuyuki 
Published: February 2008

AbstractThe sulfurization of DmpGeH3 (Dmp=2,6‐dimesitylphenyl) afforded the trinuclear germanium sulfide [DmpGe(μ‐S)]2(μ‐S)2Ge(SH)‐Dmp and a series of polythiadigermabicyclo[x.1.1]alkanes (x=3, 4, 5). The reduction of the SS bonds of these germabicycloalkanes by NaBH4 at 0 °C afforded the dinuclear mercaptogermane syn‐[DmpGe(SH)(μ‐S)2Ge(SH)‐Dmp] (5) in good yield. The reaction of [Pd(dppe)Cl2] (dppe=1,2‐bis(diphenylphosphanyl)ethane) and the dilithium salt of 5 prepared in situ by the addition of nBuLi (2 equiv) gave the Ge2PdS4 cluster [DmpGe(μ‐S)]2[(μ‐S)2Pd(dppe)], in which the dithiadigermetanedithiolate is bound to the Pd atom at the two thiolato sulfur atoms. The same reaction with [Pd(PPh3)2Cl2] gave another Ge2PdS4 cluster, [DmpGe(μ‐S)]2[(μ‐S)2Pd(PPh3)], but with the dithiadigermetanedithiolate and the Pd center conjoined through a μ‐S atom between the two germanium atoms in addition to the two thiolato sulfur atoms to form a highly distorted cluster core. The formation of two different types of Ge2PdS4 clusters represents the usefulness of 5 in the synthesis of various polynuclear complexes composed of germanium and transition metals.
Pulsed electromagnetic fields induced femoral metaphyseal bone thickness changes in the rat
Authors: Márquez‐Gamiño S. , Sotelo F. , Sosa M. , Caudillo C. , Holguín G. , Ramos M. , Mesa F. , Bernal J. , Córdova T. 
Published: February 2008

AbstractThe effect of 1 Hz, 30 mT pulsed magnetic fields on young adult rat femoral metaphyseal bone thickness was assessed. Ten same litter, female Wistar rats were studied; five of them underwent 30 min magnetic stimulation sessions for 20 consecutive days. The anterior and posterior cortical, as well as trabecular bone transverse thicknesses were measured. The results obtained under clear field microscopy in stimulated and control histological cuts were (in µm) 398 ± 32 versus 260 ± 22 (P = 0.002), 380 ± 68 versus 252 ± 21 (P = 0.03), and 168 ± 11 versus 112 ± 11 (P = 0.002), respectively. The transcranial magnetic stimulation system, approved for human therapy, generates pulsed electromagnetic fields, which induce a significant thickness increase in cortical and trabecular in vivo stimulated bone tissues. This is the first time this effect in healthy animals is shown. Bioelectromagnetics 29:406–409, 2008. © 2008 Wiley‐Liss, Inc.
Self‐assembled polyhydroxy fatty acids vesicles: a mechanism for plant cutin synthesis
Authors: Heredia‐Guerrero José A. , Benítez José J. , Heredia Antonio 
Published: February 2008

AbstractDespite its biological importance, the mechanism of formation of cutin, the polymeric matrix of plant cuticles, has not yet been fully clarified. Here, for the first time, we show the participation in the process of lipid vesicles formed by the self‐assembly of endogenous polyhydroxy fatty acids. The accumulation and fusion of these vesicles (cutinsomes) at the outer part of epidermal cell wall is proposed as the mechanism for early cuticle formation. BioEssays 30:273–277, 2008. © 2008 Wiley Periodicals, Inc.
Parasitism genes and host range disparities in biotrophic nematodes: the conundrum of polyphagy versus specialisation
Authors: Blok Vivian C. , Jones John T. , Phillips Mark S. , Trudgill David L. 
Published: February 2008

AbstractThis essay considers biotrophic cyst and root‐knot nematodes in relation to their biology, host–parasite interactions and molecular genetics. These nematodes have to face the biological consequences of the physical constraints imposed by the soil environment in which they live while their hosts inhabit both above and below ground environments. The two groups of nematodes appear to have adopted radically different solutions to these problems with the result that one group is a host specialist and reproduces sexually while the other has an enormous host range and reproduces by mitotic parthenogenesis. We consider what is known about the modes of parasitism used by these nematodes and how it relates to their host range, including the surprising finding that parasitism genes in both nematode groups have been recruited from bacteria. The nuclear and mitochondrial genomes of these two nematode groups are very different and we consider how these findings relate to the biology of the organisms. BioEssays 30:249–259, 2008. © 2008 Wiley Periodicals, Inc.