bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increased cerebral blood flow after leukapheresis for acute myelogenous leukemia
Authors: Kasner Margaret T. , Laury Adrienne , Kasner Scott E. , Carroll Martin , Luger Selina M. 
Published: July 2007

AbstractLeukapheresis is often considered in the management of acute myelogenous leukemia (AML) with hyperleukocytosis and its sequelae, including myocardial infarction, pulmonary complications, and stroke. It is utilized on the assumption that leukapheresis improves blood rheology. We present a woman with AML and a history of meningioma encasing her left internal carotid artery. She presented with hyperleukocytosis and symptoms of ischemia. As her white blood cell continued to rise despite initiation of hydroxyurea therapy, she underwent leukapheresis emergently. Transcranial Doppler ultrasound demonstrated increased flow velocities in the left internal carotid and the right middle cerebral arteries, which normalized after leukapheresis. This is the first documentation that leukapheresis, in combination with hydroxyurea, improves cerebral hemodynamics in a patient with AML. Am. J. Hematol., 2007. © 2007 Wiley‐Liss, Inc.
Exacerbation of experimental autoimmune encephalomyelitis after withdrawal of phenytoin and carbamazepine
Authors: Black Joel A. , Liu Shujun , Carrithers Michael , Carrithers Lisette M. , Waxman Stephen G. 
Published: July 2007

AbstractObjectiveIn vitro observations and studies in murine experimental autoimmune encephalomyelitis (EAE) have shown protective effects of sodium channel blockers on central nervous system axons and improved clinical status when treatment is continued throughout the period of observation. Several clinical studies of sodium channel blockers are under way in patients with multiple sclerosis. Here we asked whether a protective effect would persist after withdrawal of a sodium channel blocker.MethodsWe studied a mouse model of myelin oligodendrocyte glycoprotein–induced EAE treated with phenytoin or carbamazepine.ResultsBoth phenytoin and carbamazepine significantly improved the clinical course of the disease. Withdrawal of phenytoin resulted in acute exacerbation, accompanied by a significantly increased inflammatory infiltrate within the central nervous system and the death of nearly 60% of EAE mice. There were no clinical worsening or deaths in control mice after withdrawal of phenytoin. Withdrawal of carbamazepine led to acute worsening of EAE symptoms, increased inflammatory infiltrate, and was associated with the death of 8% of mice.InterpretationThese results, together with results showing effects of sodium channel blockers in immune cells, raise questions about the long‐term effects of sodium channel blockers in neuroinflammatory disorders, and suggest that clinical studies of sodium channel blockers in these disorders should be planned carefully. Ann Neurol 2007
Polyurethane composites based on oil palm empty fruit bunches: Effect of isocyanate/hydroxyl ratio and chemical modification of empty fruit bunches with toluene diisocyanate and hexamethylene diisocyanate on mechanical properties
Authors: Rozman H. D. , Ahmad Hilme K. R. , Abubakar A. 
Published: July 2007

AbstractThis study focuses on the effect of isocyanate (NCO)/hydroxyl (OH) group ratios and chemical modification of oil palm empty fruit bunches (EFBs) with toluene diisocyanate (TDI) and hexamethylene diisocyanate (HMDI) on the mechanical properties of EFB–polyurethane (PU) composites. The tensile, flexural, and impact properties are affected by the NCO/OH ratios. The tensile strengths, flexural strengths, and toughness increase as the NCO/OH increases; however, the modulus decreases. The reduction in the modulus is attributable to the increased flexibility of the PU linkages. Chemical modification of the EFBs increases the tensile strength, flexural strength, and toughness; however, the modulus is lowered as the percentage of treated EFB is increased. Impact strength results show that the strength increases as the NCO/OH ratio is increased. At NCO/OH ratios of 1.0 and 1.1, the composites with HMDI‐treated fibers exhibit higher impact strength than those with TDI‐treated and untreated fibers, respectively. This may be due to the longer and more flexible chain length of HMDI as compared to TDI, which enables the composites to absorb more energy before failure. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Studies of precipitated polymerization of acrylamide with quaternary ammonium cationic comonomer in potassium citrate solution
Authors: Li Gang , Yang Chao , He Yangang , Yang Fang , Yu Xueqing 
Published: July 2007

AbstractCopolymer particles consisting of acrylamide (AM) and cationic comonomer 2‐methyl acryloyloxyethyl trimethyl ammonium chloride (DMC) were prepared by precipitation polymerization in an solution of potassium citrate using ammonium persulfate ((NH4)2S2O8) and sodium sulfite (Na2SO3) as an initiator. The product poly(acrylamide‐2‐methyl acryloyloxyethyl trimethyl ammonium chloride) [Poly(DMC‐AM)] is a water‐soluble cationic polyelectrolyte. The solubility of DMC, AM and Poly(DMC‐AM) in potassium citrate solution were measured, combined with the theory of solubility parameter, and the experiment results indicate that the solubility of DMC and AM is much higher than that of Poly(DMC‐AM), and also the mechanism of copolymer precipitated in salt solution was discussed. The factors influencing the conversion of comonomers were examined, such as salt mass fraction, polymerization temperature, monomers mass fraction, initiator mass fraction, and so on. The results of experiments indicate that the best conditions are salt mass fraction = 57%, monomers mass fraction = 3%, m(DMC) : m(AM) = 3 : 1, initiator mass fraction = 0.08%, polymerization temperature = 50°C, reaction time = 2 h, and the conversion is 86.4%. And the qualitative analysis experimental method for copolymer by infrared absorption spectrum show that [Poly(DMC‐AM)] was successfully synthesized by precipitation polymerization. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
NR/PP thermoplastic vulcanizates: Selection of optimal peroxide type and concentration in relation to mixing conditions
Authors: Thitithammawong A. , Nakason C. , Sahakaro K. , Noordermeer J. W. M. 
Published: July 2007

AbstractThermoplastic vulcanizates (TPVs) from natural rubber (NR) and polypropylene (PP) were studied, prepared by dynamic vulcanization during melt mixing, using various peroxides to crosslink the rubber phase. The objective was to find a proper balance between degree of crosslinking of the rubber and degradation of the PP‐phase, and the tendency of the peroxide to form smelly by‐products, in particular acetophenone. Four types of peroxides were investigated: 2,5‐dimethyl‐2,5‐di(tert‐butyl‐peroxy) hexyne‐3 (DTBPHY), 2,5‐dimethyl‐2,5‐di(tert‐butyl‐peroxy) hexane (DTBPH), di(tert‐butylperoxyisopropyl) benzene (DTBPIB), and dicumyl peroxide (DCP), at two mixing temperatures: 160 and 180°C for a 60/40 NR/PP TPV. The maximum and final mixing torques are clearly related to the intrinsic decomposition temperature of the particular peroxide used, where DCP and DTBPIB turn out to be effective at 160°C, whereas the other two require a higher temperature of 180°C. The best mechanical properties, tensile strength, elongation at break and compression set are obtained at lower mixing temperature with DCP and DTBPIB, presumably due to less degradation of the NR and PP. Unfortunately, these two peroxides form more smelly by‐products than DTBPHY and DTBPH. Dependent on the requirements of the pertinent application, a balanced selection needs to be made between the various factors involved to obtain an optimal product performance of these NR/PP TPVs. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Effect of clay on mechanical and gas barrier properties of blown film LDPE/clay nanocomposites
Authors: Arunvisut Supong , Phummanee Sutthipat , Somwangthanaroj Anongnat 
Published: July 2007

AbstractLow density polyethylene (LDPE)/clay nanocomposites, which can be used in packaging industries, were prepared by melt‐mix organoclay with polymer matrix (LDPE) and compatibilizer, polyethylene grafted maleic anhydride (PEMA). The pristine clay was first modified with alkylammonium salt surfactant, before melt‐mixed in twin screw extruder attached to blown‐film set. D‐spacing of clay and thermal behavior of nanocomposites were characterized by Wide‐Angle X‐ray Diffraction (WAXD) and differential scanning calorimetry (DSC), respectively. WAXD pattern confirmed the increase in PEMA contents exhibited better dispersion of clay in nanocomposites. Moreover, DSC was reported the increased PEMA contents caused the decrease in degree of crystallinity. Mechanical properties of blown film specimens were tested in two directions of tensile tests: in transverse tests (TD tests) and in machine direction tests (MD tests). Tensile modulus and tensile strength at yield were improved when clay contents increased because of the reinforcing behavior of clay on both TD and MD tests. Tensile modulus of 7 wt % of clay in nanocomposite was 100% increasing from neat LDPE in TD tests and 17% increasing in MD tests. However, elongation at yield decreased when increased in clay loading. Oxygen permeability tests of LDPE/clay nanocomposites also decreased by 24% as the clay content increased to 7 wt %. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Effect of silane‐coupling agents on interfacial properties of CF/PI composites
Authors: He J. M. , Huang Y. D. 
Published: July 2007

AbstractIn this article, to form a structure‐controlled interface, carbon fiber (CF) surfaces were first activated by plasma technique and then hydroxylated by LiAlH4 treatment, and then were reacted with a suit of silane‐coupling agents terminated with desired functional groups to form thin films, which further reacted with polyimide (PI) resin to generate a strong adhesion interface. The morphology, structure, and composition of CF surfaces before and after treatment were investigated by atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), and X‐ray photoelectron spectroscopy (XPS), respectively. The results of FTIR and XPS analysis showed that silane‐coupling agents were successfully chemisorbed onto the CF surfaces by the hydrolysis and condensation reactions. The interfacial shear strength of the CF/PI microcomposites was evaluated by the microbond technique. The results showed that the types of the interfacial functional groups, especially the vinyl end groups in vinyltriethoxysilane (VS), which can react with PI resin, had very significant influence on the improvement of the interfacial adhesion properties of composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Manipulating the phase morphology in PPS/PA66 blends using clay
Authors: Zou Hao , Ning Nanying , Su Run , Zhang Qin , Fu Qiang 
Published: July 2007

AbstractBy adding a small amount of clay into poly(p‐phenylene sulfide) (PPS)/polyamide 66 blends, the morphology was found to change gradually from sea–island into cocontinuity and lamellar supramolecular structure, as increasing of clay content. Clay was selectively located in the PA66 phase, and the exfoliated clay layers formed an edge‐contacted network. The change of morphology is not caused by the change of volume ratio and viscosity ratio but can be well explained by the dynamic interplay of phase separation between PPS and PA66 through preferential adsorption of PA66 onto the clay layers and through layer–layer repulsion. This provides a means of manipulating the phase morphology for the immiscible polymer blends. The mechanical and tribological properties of PPS/PA66 blends with different phase morphologies (different clay contents) were studied. Both tensile and impact strength of the blends were found obviously increased by the addition of clay. The antiwear property was greatly improved for the blends with cocontinuous phase form. Our work indicates that the phase‐separating behavior of polymer blends contained interacting clay can be exploited to create a rich diversity of new structures and useful nanocomposites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Surface modification of aramid fibers with γ‐ray radiation for improving interfacial bonding strength with epoxy resin
Authors: Zhang Yanhua , Huang Yudong , Liu Li , Wu Lina 
Published: July 2007

AbstractCo60 γ‐ray radiation as a simple and convenient method for surface modification of Armos aramid fibers was introduced in this article. Two kinds of gas mediums, N2 and air, were chosen to modify aramid fiber surface by γ‐ray irradiation. After fiber surface treatment, the interlaminar shear strength values of aramid/epoxy composites were enhanced by about 17.7 and 15.8%, respectively. Surface elements of aramid fibers were determined by XPS, the analysis of which showed that the ratio of oxygen/carbon was increased. The crystalline state of aramid fibers was determined by X‐ray diffraction instrument. The surface topography of fibers was analyzed by atomic force microscopy and scanning electron microscope. The degree of surface roughness and the wettability of fiber surface were both enhanced by γ‐ray radiation. The results indicated that γ‐ray irradiation technique, which is a suitable way of batch process for industrialization, can significantly improve the surface properties of aramid fibers reinforced epoxy resin matrix composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
In situ fiber composites based on metallocene polyethylene matrices
Authors: Cárdenas Miguel Angel , Perera Rosestela , Villarreal Norky , Rosales Carmen , Pastor José María 
Published: July 2007

AbstractBinary blends of metallocene polyethylenes with polyethylenes and polypropylene were made in a co‐rotating twin‐screw extruder. A stretching process was carried out afterwards in the melt state at the extruder's exit to study the effect of the induced orientation on their thermal and tensile properties. Capillary rheometry was performed to the neat polymers to determine the viscosity ratios of the blend components as a function of the shear rate. SEM and Micro‐Raman analyses were done to study the morphology of the stretched and nonstretched blends. As expected, an increase in the modulus and tensile stress was obtained through blending. Additionally, the elastomeric behavior of the metallocene polyethylene (mPE) sample is observed in all blends and it was not lost through blending. Nevertheless, all blends without stretching exhibited a negative deviation of the linear additivity rule of blending. The stretching of the blends made with metallocene polyethylenes as matrices and other types of PEs as dispersed phase did not improve the tensile properties, although some differences in the dispersed phases were found by DSC, and microfibrils could be seen in the drawn mPE/HDPE blend. However, blending with PP produced an improvement in the modulus and tensile stress of the drawn samples in comparison to their undrawn counterpart. The tensile stresses of PP blends are more sensitive to the drawing process than the modulus, which can be attributed to the appearance of large fibril fractions during this process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Investigating the jet stretch in the wet spinning of PAN fiber
Authors: Zeng Xiaomei , Hu Juan , Zhao Jiongxin , Zhang Youwei , Pan Ding 
Published: July 2007

AbstractThe jet stretch of wet‐spun PAN fiber and its effects on the cross‐section shape and properties of fibers were investigated for the PAN‐DMSO‐H2O system. Evidently, the spinning parameters, such as dope temperature, bath concentration, and bath temperature, influenced the jet stretch. Also, under uniform conditions, the postdrawing ratio changed as well as that of jet stretch. When coagulation temperature was 35°C simultaneously with bath concentration of 70%, jet stretch impacted obviously the cross‐section shapes of PAN fiber, but had little effect when the temperature was below 10°C or above 70°C. As the jet stretch ratio increased, the crystallinity, crystal size, sonic orientation, and mechanical properties of the as‐spun fiber changed rapidly to a major value for jet stretch ratio of 0.9 where the cross section of as‐spun fiber was circular. With further increasing of jet stretch ratio, the properties changed slightly but the fiber shape was not circular. The results indicated that appropriate jet stretch, under milder formation conditions in wet‐spinning, could result in the higher postdrawing ratio and circular profile of PAN fiber, which were helpful to produce round PAN precursor with minor titer and perfect properties for carbon fiber. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Effect of furfuryl alcohol addition on the cure of furfuryl alcohol resin used in the glassy carbon manufacture
Authors: Gaefke C. B. , Botelho E. C. , Ferreira N. G. , Rezende M. C. 
Published: July 2007

AbstractGlassy carbon can be manufactured practically without pores, named Monolithic Vitreous Carbon (MVC) or presenting up to 98% in transport pore volume, foam form, denominated Reticulated Vitreous Carbon (RVC). The glassy carbon processing is affected by some processing parameters, among them it can be cited the resin viscosity. The present work involves the optimization of RVC manufacture by monitoring the polyurethane (PU) foam impregnation with furfuryl alcohol resin with different viscosity values, which were obtained by dilution of the resin with different amounts of furfuryl alcohol. The resin samples used in the PU impregnation were characterized by thermal and rheological analyses. These results were correlated with scanning electron microscopy observations and compression test results of the impregnated polyurethane foam. The results show that the rheological behavior of the resin has significant influence on the polymerization step, affecting the homogeneity of impregnated foam and, consequently, its final properties, mainly the mechanical one. The impregnated foam prepared with the furfuryl alcohol resin diluted with 10% of furfuryl alcohol (η = 11.4 Pa s) showed higher compression values (0.26 MPa). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Synthesis, characterization, thermal stability, conductivity, and band gap of a new aromatic polyether containing an azomethine as a side
Authors: Kaya İsmet , Yıldırım Mehmet 
Published: July 2007

AbstractIn this study, the oxidative polycondensation reaction conditions of 4‐[(4‐methylphenyl)iminomethyl]phenol (4‐MPIMP) were studied by using oxidants such as air O2, H2O2, and NaOCl in an aqueous alkaline medium between 50 and 90°C. The structures of the synthesized monomer and polymer were confirmed by FTIR, UV–vis, 1H–13C‐NMR, and elemental analysis. The characterization was made by TGA‐DTA, size exclusion chromatography (SEC), and solubility tests. At the optimum reaction conditions, the yield of poly‐4‐[(4‐methylphenyl)iminomethyl]phenol (P‐4‐MPIMP) was found to be 28% for air O2 oxidant, 42% for H2O2 oxidant, and 62% for NaOCl oxidant. According to the SEC analysis, the number–average molecular weight (Mn), weight–average molecular weight (Mw), and polydispersity index values of P‐4‐MPIMP were found to be 4400 g mol−1, 5100 g mol−1, and 1.159, using H2O2, and 4650 g mol−1, 5200 g mol−1, and 1.118, using air O2, and 5100 g mol−1, 5900 g mol−1, and 1.157, using NaOCl, respectively. According to TG analysis, the weight losses of 4‐MPIMP and P‐4‐MPIMP were found to be 85.37% and 72.19% at 1000°C, respectively. P‐4‐MPIMP showed higher stability against thermal decomposition. Also, electrical conductivity of the P‐4‐MPIMP was measured, showing that the polymer is a typical semiconductor. The highest occupied molecular orbital and the lowest unoccupied molecular orbital energy levels and electrochemical energy gaps (E) of 4‐MPIMP and P‐4‐MPIMP were found to be −5.76, −5.19; −3.00, −3.24; 2.76 and 1.95 eV, respectively. According to UV–vis measurements, optical band gaps (Eg) of 4‐MPIMP and P‐4‐MPIMP were found to be 3.34 and 2.82 eV, respectively. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Lignins for phenol replacement in novolac‐type phenolic formulations, part I: Lignophenolic resins synthesis and characterization
Authors: Tejado A. , Kortaberria G. , Peña C. , Labidi J. , Echeverría J. M. , Mondragon Inaki 
Published: July 2007

AbstractSeveral lignin (L)‐based novolac‐type phenolic prepolymers with two phenol (P) substitution degrees have been synthesized using three L from different origin (kraft pine L, soda/anthraquinone (AQ) flax L, and sulfonated kraft softwood L). These lignophenolic (LPF) resins have been characterized by means of free P and formaldehyde (F) analysis, viscosity, chemical structure (FTIR), and thermal behavior (DSC). Temperature at which curing reaction begins (DSC), hardening time at several curing temperatures (rheology) and volumetric changes (PVT) have also been determined for the curing process with 10 wt % hexamethylenetetraamine (HMTA). All the results have been compared to those obtained for a commercial novolac. Depending on the L type employed a homogeneous material with lower curing onset temperature and gelation time than reference PF can be obtained even at high P substitution level (45 wt %). © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007
Changes of melanosome morphology associated with the differentiation of epidermal melanocytes in slaty mice
Authors: Hirobe Tomohisa , Abe Hiroyuki 
Published: July 2007

AbstractThe slaty (Dctslt) mutation is known to reduce the activity of dopachrome tautomerase, which converts dopachrome to 5,6‐dihydroxyindole‐2‐carboxylic acid in the pathway of eumelanin synthesis and to inhibit melanosome maturation in melanocytes. However, it is not known whether the inhibition of melanosome maturation in slaty melanocytes is developmentally regulated. To address this point, changes in the morphology and maturation of melanosomes in cultured epidermal melanocytes derived from newborn mice of wild‐type (black) and slaty mutant were surveyed under the electron microscope. In black melanocytes (Dct+), almost all melanosomes were elliptical stage IV melanosomes. However, in slaty melanocytes, numerous spherical stage III melanosomes with globular depositions of pigment in addition to elliptical stage III melanosomes with intraluminal fibrils were observed. Mixed‐type melanosomes containing both globular deposition and intraluminal fibrils of pigment were also observed. In slaty melanocytes, spherical and mixed‐type melanosomes were gradually decreased after birth, whereas elliptical melanosomes were gradually increased. Stage IV melanosomes were very few in slaty melanocytes, and the number did not increase after birth. These results suggest that the slaty mutation blocks the melanosome maturation at stage III and affects the melanosome morphology (elliptical or spherical) in a developmental stage‐specific manner. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.