bluuebunny/crossref_metadata_2025 huggingface dataset:
Augmentation of both hemolysate-induced contraction and activation of protein kinase C by submaximum activation in canine cerebral arteries in vitro
Authors: Kawamata Takakazu , Peterson John W. , Bun Takao , Zervas Nicholas T.
Published: June 2009

✓ Although phorbol esters, synthetic activators of protein kinase C (PKC), can stimulate large increases in the binding of cytosolic PKC to form membrane-bound PKC (PKCm, an indicator of PKC activation), the authors report that even small increases in PKCm induced by phorbol esters (8–12% of total PKC content) can be associated with significant PKC-mediated contractions in vitro (50–85% of maximum) in normal canine cerebral arteries. Increases in PKCm of similarly small magnitude were found in vitro when control artery segments were exposed to hemolysate, but only if the arterial smooth-muscle cells were first slightly depolarized by increased extracellular potassium to values of membrane potential similar to those observed in canine cerebral arteries during chronic cerebral vasospasm. These increases in PKCm (6–8% of total PKC content) coincided with a greatly augmented contractile response to hemolysate. These results show that the previous observation of only a small increase in PKCm (approximately 7% of total PKC content) after experimental subarachnoid hemorrhage in the canine model does not preclude a potentially important role for PKC-mediated contraction in the pathogenesis of cerebral vasospasm.
Effects of ifenprodil, a polyamine site NMDA receptor antagonist, on reperfusion injury after transient focal cerebral ischemia
Authors: Doğgan Aclan , Rao A. Muralikrishna , Başkaya Mustafa K. , Rao V. L. Raghavendra , Rastl Jane , Donaldson David , Dempsey Robert J.
Published: June 2009

✓ Polyamines andN-methyl-d-aspartate (NMDA) receptors are both thought to play an important role in secondary neuronal injury after cerebral ischemia. Ifenprodil, known as a noncompetitive inhibitor of polyamine sites at the NMDA receptor, was studied after transient focal cerebral ischemia occurred. Spontaneously hypertensive male rats, each weighing between 250 and 350 g, underwent 3 hours of tandem middle cerebral artery (MCA) and common carotid artery occlusion followed by reperfusion for a period of 3 hours or 21 hours. Intravenous ifenprodil (10 µg/kg/minute) or saline infusion was started immediately after the onset of MCA occlusion and continued throughout the ischemic period. Physiological parameters including blood pressure, blood gas levels, blood glucose, hemoglobin, and rectal and temporal muscle temperatures were monitored. Six rats from each group were evaluated at 6 hours postocclusion for brain water content, an indicator of brain edema, and Evans blue dye extravasation for blood-brain barrier breakdown. Infarct volume was also measured in six rats from each group at 6 and 24 hours postocclusion. Ifenprodil treatment significantly reduced brain edema (82.5 ± 0.4% vs. 83.5 ± 0.4%, p < 0.05) and infarct volume (132 ± 14 mm3vs. 168 ± 25 mm3, p < 0.05) compared with saline treatment, with no alterations in temporal muscle (brain) or rectal (body) temperature (35.9 ± 0.4°C vs. 36.2 ± 0.2°C; 37.7 ± 0.4°C vs. 37.6 ± 0.6°C; not significant). These results demonstrate that ifenprodil has neuroprotective properties after ischemia/reperfusion injury in the absence of hypothermia. This indicates that antagonists selective for the polyamine site of the NMDA receptors may be a viable treatment option and helps to explain some of the pathophysiological mechanisms involved in secondary injury after transient focal cerebral ischemia has occurred.
Pre- and postischemic effects of the NMDA receptor antagonist dizocilpine maleate (MK-801) on collateral cerebral blood flow
Authors: Robertson Scott C. , Wetjen Nicholas M. , Beer Bradley J. , Loftus Christopher M.
Published: June 2009

✓ The authors studied the effects of pre- and postischemic administration of dizocilpine maleate (MK-801) on collateral and regional cerebral blood flow (CBF). The ischemic penumbra appears to benefit most from the neuroprotective effects of MK-801. The precise mechanism by which MK-801 provides this neuroprotection remains controversial. Alterations in CBF have been demonstrated with MK-801 administration, but whether the response is an increase or decrease in flow has remained unclear.

A left-sided craniectomy was performed in 20 dogs. A branch of the middle cerebral artery (MCA) was cannulated and collateral blood supply—dependent tissue (CDT) was identified using the “shadow flow” technique. Regional CBF was measured using radiolabeled microspheres. Six dogs received MK-801 (1 mg/kg administered intravenously) before they underwent MCA branch occlusion; the remaining 14 dogs received MK-801 after they underwent MCA occlusion. Cerebral blood flow and vascular pressures were measured 30 and 60 minutes after MK-801 administration. In animals that received MK-801 before MCA occlusion, CBF did not change significantly from baseline values before or after occlusion. In contrast, in animals that received MK-801 after MCA occlusion, CBF was significantly reduced in all regions of the brain, including the CDT. Collateral blood supply—dependent tissue showed a 51.7% reduction in flow, whereas normal CBF was reduced by 29.7%. The MK-801 induced cerebral vasoconstriction in both groups. The neuroprotective effects of MK-801 do not appear to be caused by the augmentation of collateral or global cerebral circulation and, in fact, may block the glutamate-mediated vasodilation that occurs during ischemia.
Resection of a large temporooccipital parenchymal arteriovenous fistula by using deep hypothermic circulatory bypass
Authors: Meyer Fredric B. , Grady Robert E. , Abel Martin D. , Nichols Douglas A. , Caminha Sergio S. , Robb Richard A. , Bates Lisa M.
Published: June 2009

✓ The authors believe this to be the first published case in which a deep hypothermic cardiopulmonary bypass was used to facilitate resection of a large parenchymal arteriovenous fistula. The use of this procedure facilitated resection of the lesion by allowing compression and manipulation of large venous varices that were overlying the deeper arterial feeding vessels. The surgical rationale, technique, and intra- and postoperative management are discussed.
Sonochemical Preparation of Polymer Nanocomposites
Authors: Zhang Ke , Park Bong-Jun , Fang Fei-Fei , Choi Hyoung Jin
Published: June 2009

Thisreview covers sonochemical fabrication of polymer nanocomposites. In addition to its application to the synthesis of various polymeric systems, due to its powerful efficiency, sonochemistry has been widely used not only as the assistant of dispersion for nanomaterials such as carbon nanotubes (CNT) and organophillic clay, but also as a special initiator to enhance polymerization for fabrication of polymer nanocomposites with CNT and metallic nanoparticles. Recent developments in the preparation of multi-walled carbon nanotube/polymer nanocomposites with polystyrene and PMMA, magnetic particle/CNT composites and polymer/clay nanocomposites along with their physical characteristics and potential engineering applications will be introduced. Physical characterizations include morphological, thermal, and rheological properties under either an applied electric or magnetic field.
Optimal Detection Range of RFID Tag for RFID-based Positioning System Using the k-NN Algorithm
Authors: Han Soohee , Kim Junghwan , Park Choung-Hwan , Yoon Hee-Cheon , Heo Joon
Published: June 2009

Positioning technology to track a moving object is an important and essential component of ubiquitous computing environments and applications. An RFID-based positioning system using the k-nearest neighbor (k-NN) algorithm can determine the position of a moving reader from observed reference data. In this study, the optimal detection range of an RFID-based positioning system was determined on the principle that tag spacing can be derived from the detection range. It was assumed that reference tags without signal strength information are regularly distributed in 1-, 2- and 3-dimensional spaces. The optimal detection range was determined, through analytical and numerical approaches, to be 125% of the tag-spacing distance in 1-dimensional space. Through numerical approaches, the range was 134% in 2-dimensional space, 143% in 3-dimensional space.
Liquid Crystal Emulsions as the Basis of Biological Sensors for the Optical Detection of Bacteria and Viruses
Authors: Sivakumar Sri , Wark Kim L. , Gupta Jugal K. , Abbott Nicholas L. , Caruso Frank
Published: June 2009

A versatile sensing method based on monodisperse liquid crystal (LC) emulsion droplets detects and distinguishes between different types of bacteria (Gram +ve and −ve) and viruses (enveloped and non‐enveloped). LCs of 4‐cyano‐4'‐pentylbiphenyl transition from a bipolar to radial configuration when in contact with Gram −ve bacteria (E. coli) and lipid‐enveloped viruses (A/NWS/Tokyo/67). This transition is consistent with the transfer of lipid from the organisms to the interfaces of the micrometer‐sized LC droplets. In contrast, a transition to the radial configuration is not observed in the presence of Gram +ve bacteria (Bacillus subtilis and Micrococcus luteus) and non‐enveloped viruses (M13 helper phage). The LC droplets can detect small numbers of E. coli bacteria (1–5) and low concentrations (104 pfu mL−1) of A/NWS/Tokyo/67 virus. Monodisperse LC emulsions incubated with phosholipid liposomes (similar to the E. coli cell wall lipid) reveal that the orientational change is triggered at an area per lipid molecule of ∼46 Å2 on an LC droplet (∼1.6 × 108 lipid molecules per droplet). This approach represents a novel means to sense and differentiate between types of bacteria and viruses based on their cell‐wall/envelope structure, paving the way for the development of a new class of LC microdroplet‐based biological sensors.
Mechanisms of particle dispersion in a turbulent, square duct flow
Authors: Fairweather Michael , Yao Jun
Published: June 2009

Particle dispersion in a square duct flow is studied using large eddy simulation combined with Lagrangian particle tracking under conditions of one‐way coupling. The flow has a bulk Re = 250 k, with six particle sizes ranging from 5 to 1000 μm. Results obtained for the fluid phase show good agreement with experimental data. For particles, predictions demonstrate that secondary flows within the duct dominate small particle dispersion and result in a uniform distribution, whereas gravity promotes the deposition of large particles on the duct floor. For the largest particles, the secondary flows contribute to particle concentration in corners on the duct floor, with these particles also clustering in low‐velocity regions close to the floor. A detailed analysis of the influence of the flow on particle distribution is provided through consideration of the particle dispersion function, with the mechanisms of particle dispersion elucidated using a dynamical analysis. © 2009 American Institute of Chemical Engineers AIChE J, 2009
Synergistic antitumor effects of lenalidomide and rituximab on mantle cell lymphoma in vitro and in vivo
Authors: Zhang Liang , Qian Zhengzi , Cai Zhen , Sun Luhong , Wang Huaqing , Bartlett J. Blake , Yi Qing , Wang Michael
Published: June 2009

Rituximab (RTX), a chimeric anti‐CD20 antibody, is associated with direct induction of apoptosis and antibody‐dependent cell‐mediated cytotoxicity (ADCC) with clinical efficacy in mantle cell lymphoma (MCL). Lenalidomide (LEN), a novel immunomodulatory agent, sensitizes tumor cells and enhances ADCC. Our study attempted to elucidate the mechanism of LEN‐enhanced RTX‐mediated cytotoxicity of MCL cells. We found that LEN and RTX induced growth inhibition of both cultured and fresh primary MCL cells. LEN enhanced RTX‐induced apoptosis via upregulating phosphorylation of c‐Jun N‐terminal protein kinases (JNK), Bcl‐2, Bad; increasing release of cytochrome‐c; enhancing activation of caspase‐3, ‐8, ‐9 and cleavage of PARP. Meanwhile, LEN activated NK cells and increased CD16 expression on CD56lowCD16+ NK cells. Whole PBMCs but not NK cell‐depleted PBMCs treated with LEN augmented 30% of RTX‐dependent cytotoxicity. Daily treatment with LEN increased NK cells by 10‐folds in SCID mice, and combination of LEN and RTX decreased tumor burden and prolonged survival of MCL‐bearing SCID mice. Taken together, our study demonstrates that LEN plus RTX provides a synergistically therapeutic effect on MCL cells by enhancing apoptosis and RTX‐dependent NK cell‐mediated cytotoxicity and may be an optimal combination in the clinical trial of relapsed or refractory MCL. Am. J. Hematol. 2009. © 2009 Wiley‐Liss, Inc.
Variation across the agricultural season in organophosphorus pesticide urinary metabolite levels for Latino farmworkers in eastern North Carolina: Project design and descriptive results
Authors: Arcury Thomas A. , Grzywacz Joseph G. , Chen Haiying , Vallejos Quirina M. , Galván Leonardo , Whalley Lara E. , Isom Scott , Barr Dana B. , Quandt Sara A.
Published: June 2009

Background

Community Participatory Approach to Measuring Farmworker Pesticide Exposure, PACE3, used a longitudinal design to document pesticide biomarkers among farmworkers. This article presents an overview of PACE3 and provides a descriptive analysis of participant characteristics and one set of pesticide biomarkers, the dialkylphosphate (DAP) urinary metabolites of organophosphorus (OP) pesticides.

Methods

Two hundred eighty seven farmworkers were recruited during 2007 from 44 farmworker camps in 11 eastern North Carolina counties. Participants provided interviews, urine samples, blood samples, and saliva samples up to four times at monthly intervals beginning in May. A total of 939 data points were collected.

Results

Farmworkers were largely men (91.3%) from Mexico (94.8%) with a mean age of 33.7 years (SE 0.82); 23.3% spoke an indigenous language. Across all data points, frequencies of detection and median urinary concentrations were 41.3% and 0.96 µg/L for dimethylphosphate (DMP), 78.3% and 3.61 µg/L for dimethylthiophosphate (DMTP), 33.3% and 0.04 µg/L for dimethyldithiophosphate (DMDTP), 40.5% and 0.87 µg/L for diethylphosphate (DEP), 32.3% and 0.17 µg/L for diethylthiophosphate (DETP), and 8.09% and 0.00 µg/L for diethyldithiophosphate (DEDTP). The frequencies of detection and urinary concentrations of the DAP metabolites increased during the season.

Conclusions

More PACE3 participants were from Mexico, male, migrant workers, and spoke an indigenous language compared to national data. PACE3 participants had comparable frequencies of detection and urinary metabolite concentrations with participants in other studies. Variability in the frequencies of detection and urinary concentrations of the DAP metabolites indicates the importance of longitudinal studies of biomarkers of currently used pesticides in farmworker populations. Am. J. Ind. Med. 52:539–550, 2009. © 2009 Wiley‐Liss, Inc.
Estimating the probability of de novo HD cases from transmissions of expanded penetrant CAG alleles in the Huntington disease gene from male carriers of high normal alleles (27–35 CAG)
Authors: Hendricks Audrey E. , Latourelle Jeanne C. , Lunetta Kathryn L. , Cupples L. Adrienne , Wheeler Vanessa , MacDonald Marcy E. , Gusella James F. , Myers Richard H.
Published: June 2009

Huntington disease (HD) is a dominantly transmitted neurodegenerative disorder that arises from expansion of a CAG trinucleotide repeat on chromosome 4p16.3. CAG repeat allele lengths are defined as fully penetrant at ≥40, reduced penetrance at 36–39, high normal at 27–35, and normal at ≤26. Fathers, but not mothers, with high normal alleles are at risk of transmitting potentially penetrant HD alleles (≥36) to offspring. We estimated the conditional probability of an offspring inheriting an expanded penetrant allele given a father with a high normal allele by applying probability definitions and rules to estimates of HD incidence, paternal birth rate, frequency of de novo HD, and frequency of high normal alleles in the general population. The estimated probability that a male high normal allele carrier will have an offspring with an expanded penetrant allele ranges from 1/6,241 to 1/951. These estimates may be useful in genetic counseling for male high normal allele carriers. © 2009 Wiley‐Liss, Inc.
Genetic linkage of region containing theCREB1gene to depressive disorders in families with recurrent, early‐onset, major depression: A re‐analysis and confirmation of sex‐specific effect
Authors: Maher Brion S. , Hughes Hugh B. , Zubenko Wendy N. , Zubenko George S.
Published: June 2009

A previously published model‐free linkage analysis of chromosome 2q33–35, highlighted by previous case–control studies and supported by within‐family analyses employing the transmission disequilibrium test, revealed evidence of sex‐specific linkage of theCREB1‐containing region of 2q to unipolar mood disorders among women in 81 recurrent, early‐onset, major depressive disorder (RE‐MDD) families. Since it has been reported that the LODPAL program from S.A.G.E. v.4.0 used to conduct this previous linkage analysis suffers from an increased type I error rate that is exacerbated by covariates such as sex, we re‐analyzed the evidence for this sex‐specific linkage result using a simulation approach to estimate the empirical significance of our previous results. The results continue to support sex‐specific linkage of theCREB1region to mood disorders among women from families with RE‐MDD. Moreover, these results have been supported by a host of additional published findings that implicate sequence variations inCREB1in the sex‐dependent development of syndromic mood disorders, as well as related clinical features and disorders. © 2009 Wiley‐Liss, Inc.
Multiobjective optimization of molded LDPE foams characteristics using genetic algorithm
Authors: Chedly S. , Chettah A. , Ichchou M. N.
Published: June 2009

This article concerns the injection manufacturing process of molded foam sheets and their intrinsic shock and noise performances. The main goal is to optimize the physical performances of molded plastic foams at an early stage in their design and manufacturing. The effects of injection process parameters on the properties of molded LDPE foams are investigated. The input optimization parameters considered are as follows: injection temperature, mold temperature, injection speed, plasticization back pressure, and screw rotation speed during the plasticization phase. The output optimization parameters considered are as follows: density, shock absorption, and acoustic absorption. The experimental design method made use of the central composition design. This allows us to identify simplified mathematical models for input/output and to detect the most influential input in the injection process. Ultimately, models are used to carry out multiobjective optimization of injected foams characteristics in the presence of a few constraints on decision variables. This optimization is done using a very robust technique, NSGA‐II. Several two‐objective functions involving sometimes the maximization and other times minimization of foam characteristics have been studied to illustrate the procedures and explain and interpret the results obtained. One needs to solve several simpler optimization problems with just one or two decision variables (smaller amount of freedom), to gain insight and to provide help in formulating the more general multiobjective optimization problem. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Preparation of poly(butyl acrylate)‐poly(methyl methacrylate) (core‐shell)/phosphor composite particles and its application in PVC matrix
Authors: Chen Tonghua , Xu Peng , Luo Yongyue , Jiang Long , Dan Yi , Zhang Li , Zhao Kun
Published: June 2009

Luminescent poly(vinyl chloride) (PVC) plastics filling with long afterglow phosphor (SrAl2O4: Eu2+, Dy3+) were prepared via melt blending. To improve the dispersion degree of the phosphor particles and endow the compatibility with PVC matrix, SrAl2O4: Eu2+, Dy3+ was first grafted with poly(butyl acrylate)‐poly(methyl methacrylate) (core‐shell) (designed as PMMA(PBA)) by in situ emulsion polymerization. The properties of polymer/phosphor composite particles were characterized by fourier transform infrared, X‐ray photoelectron spectroscopy, and thermogravimetric analysis. The results show that the polymer had grafted onto the phosphor by chemical bond and the grating ratio was about 6.3%. The results for PVC plastics characterized by scanning electron microscopy show that the interfacial adhesion was enhanced with filling the polymer/phosphor composite particles and the compatibility of phosphor with PVC matrix was improved by coating with PMMA(PBA). And the luminescent PVC plastics filled with PMMA(PBA)/phosphor composite particles show improved mechanical properties and higher phosphorescence when the filling content was more than 3 phr compared with the unmodified phosphor. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Dynamic mechanical analysis of the interfacial changes in polypropylene/talc composites induced by different interfacial modifications from the reinforcement side
Authors: García‐Martínez J. M. , Areso S. , Taranco J. , Collar E. P.
Published: June 2009

This article is intended to establish a comprehensive interpretation of the noticeable differences in the dynamic mechanical behaviors of polypropylene/talc composites with and without modified interphases. The latter are discussed on the basis of different surface treatments applied to the reinforcement particles. To this end, a series of 75/25 (w/w) polypropylene/talc composites with and without interfacial modifications from the reinforcement side were evaluated by dynamic mechanical analysis. The proven capability of this technique analysis to follow the transitions and structural and morphological changes in organic polymers, which are largely influenced by the degree of compatibility between the components of heterogeneous materials based on polymers, was used in this study to check and discuss the kinds and efficiencies of different physisorption‐ and chemisorption‐based processes carried out on the surface of talc particles. We tackled this study by embracing the different relaxation phenomena taking place in the polymer matrix. To this end, five different temperature intervals were distinguished according to the relaxation phenomena taking place. Finally, a correlation between the parameters on the microscopic scale and others on the macroscopic scale appeared to emerge. Thus, the interfacial effects caused by the modified reinforcements could be determined by observations on either scale. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Ceric‐initiated free radical graft copolymerization of acrylonitrile onto kappa carrageenan
Authors: Hosseinzadeh Hossein
Published: June 2009

The polysaccharide, kappa carrageenan (kC), was modified using ceric‐initiated graft copolymerization of acrylonitrile (AN) under inert atmosphere in a homogeneous aqueous medium. Grafting was confirmed using FTIR spectroscopy, solubility test, elemental analysis, acid hydrolysis, and thermogravimetric analysis (TGA). kC‐graft‐poly(AN) products had a higher thermal stability than kC as revealed by TGA analysis. The polyacrylonitrile branches were isolated by acidic degradation of the carrageenan main chains and characterized by size exclusion chromatography (SEC). Residual monomers were not found by HPLC in graft copolymers stored even for longer periods. The effect of various factors affecting on grafting, i.e., concentration of the initiator, monomer, and polysaccharide as well as the reaction time and temperature were studied by conventional methods to achieve the optimum grafting parameters. The graft copolymerization reactions were kinetically investigated using semi‐empirical expressions and a suitable rate expression has been derived. According to the empirical rates of the polymerization and the graft copolymerization of AN onto kC backbone, the overall activation energy of the graft copolymerization reaction was estimated to be 20.96 kJ/mol. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Constant rotational rheological behaviors of the PAN/DMSO/nonsolvent systems
Authors: Du Weiping , Chen Huifang , Xu Yurun , Pan Ding
Published: June 2009

The constant rotational rheological behaviors of PAN/DMSO solutions with two kinds of nonsolvent (water and ethanol) have been investigated, respectively, using a cone‐plate rheometer. From viscosity measurements, the flow behavior was described within the shear rate range 0.1–1000 s−1. The PAN solutions show shear thinning at high shear rates. The viscosities of the solutions decreased with the rising of the temperature at low shear rate. H2O content has great influence on the viscosity of the solutions, depending on the hydration of H2O and PAN or desolvent effect, according to different H2O content. The role of ethanol compared with H2O was also researched and higher viscosity was found. Non‐Newtonian index, structural viscosity index Δη, and flow activation energy of the PAN/DMSO/H2O systems were also studied. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Thermal decomposition kinetics of poly(nButMA‐b‐St) diblock copolymer synthesized by ATRP
Authors: Kurt Adnan
Published: June 2009

The reaction mechanism of decomposition process and the kinetic parameters of the poly(n‐butyl methacrylate‐b‐styrene), poly(nButMA‐b‐St), diblock copolymer synthesized by atom transfer radical polymerization (ATRP) were investigated by thermogravimetric analysis (TGA) at different heating rates. TGA curves showed that the thermal decomposition occurred in one stage. The apparent activation energies of thermal decomposition for copolymer, as determined by the Kissinger's, Flynn–Wall–Ozawa and Tang methods, which does not require knowledge of the reaction mechanism (RM), were 112.52, 116.54, and 113.41 kJ/mol, respectively. The experimental results were compared with master plots, in the range of the Doyle approximation. Analysis of experimental results suggests that in the conversion range studied, 3–18%, the actual RM is an A2 sigmoidal type. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Thermal degradation analysis of polyamide 6 processed at different cycles using sequential pyrolysis
Authors: Parres Francisco , Crespo José Enrique , Nadal‐Gisbert Antonio
Published: June 2009

The principal product from the degradation of polyamide 6 (PA6) is caprolactam, which is a consequence of the intramolecular exchange (cyclization) of PA6. The information obtained from certain thermal analysis techniques, such as differential scanning calorimetry (DSC), is not sufficiently detailed to study the degradation suffered by PA6 in function of these processes, whereas the study of this degradation using other more precise techniques (sequential pyrolysis) and the application of models (Guggenheim and Kezdy‐Jaz‐Bruylants methods) gives us more detailed information on the level of degradation in the many and diverse PA6 analyzed.© 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Mechanical properties and water absorption of fiber‐reinforced polypropylene composites prepared by bagasse and beech fiber
Authors: Nourbakhsh Amir , Kouhpayehzadeh Mojgan
Published: June 2009

The present study investigates the tensile, flexural, notched Izod impact, and water absorption properties of bagasse and beech reinforced polypropylene (PP) composites as a function of fiber content. The surface of fibers was modified through the use of maleated polypropylene (MAPP) coupling agent. From this study, it was found that mechanical properties increase with an increase in fiber loading in both cases. However, the addition of wood fibers resulted in a decrease in impact strength of the composites. The water absorption property at varying fiber loading was evaluated and found maximum for the BA/PP composites. The weight gains for all specimens were less than 7%. In general, the results showed the usefulness of bagasse fiber as a good alternative and reinforcing agent for composite. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Monitoring the stability of nanosized silica dispersions in presence of polycations by a novel centrifugal sedimentation method
Authors: Petzold Gudrun , Goltzsche Christine , Mende Mandy , Schwarz Simona , Jaeger Werner
Published: June 2009

The stability of Aerosil‐silica dispersions is analyzed in dependence on the addition of polycations with different charge density and hydrophobic modification using the analytical centrifuge LUMiSizer. This novel centrifugal sedimentation method allows the direct calculation of the stability parameters like sedimentation velocity and prediction of the shelf life. The highly charged polycation poly (diallyl‐dimethylammonium chloride) (PDADMAC) is compared with tailored cationic polyelectrolytes of equal degree of polymerization but lower and different charge density as well as various hydrophobic substitutions. The used technique allows to accelerate demixing and to quantify the stability of dispersions in a direct way. All polymers under study are able to stabilize aerosil dispersions, but the shelf life strongly depends on the polymer concentration. Typically for polycations, the stability increases with the polymer concentration whereas at low‐polymer content flocculation can be detected. In this context, the behavior of PDADMAC and three cationic PVB derivatives is similar, but, whereas the stability of PDADMAC containing dispersions decreases at higher polymer concentrations, PVB derivatives are effective stabilizers at higher concentrations too. The highest increase of the stability with increasing polymer concentration is obtained with the ampholytic terpolymer TP that has the lowest cationic charge. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Compatibilization of low‐density polyethylene/cassava starch blends by potassium persulfate and benzoyl peroxide
Authors: Tanrattanakul Varaporn , Panwiriyarat Wannarat
Published: June 2009

Low‐density polyethylene (LDPE) was melt‐blended with native cassava starch in an internal mixer. The unplasticized starch content was in the range of 30–70 wt %. Potassium persulfate and benzoyl peroxide were used as initiators to generate free radicals in starch and LDPE, leading to graft copolymerization during melt blending. An enhancement of interfacial adhesion due to initiators was observed directly in scanning electron micrographs and was proven indirectly with many experiments, including tensile property testing, tear strength testing, water absorption testing, dynamic mechanical thermal analysis, thermogravimetric analysis, and soil burial testing. The tensile strength and Young's modulus of all blend compositions increased with the addition of initiators, whereas the tear strength increased in blends containing 50 wt % or more starch. The water uptake of the samples decreased significantly when initiators were added. Starch exhibited a strong effect on the α‐relaxation process of LDPE. Blends containing initiators provided higher α‐relaxation temperatures than blends without initiators. The increase in the interfacial adhesion of the blends also affected the biodegradation of starch. A lesser biodegradation rate of starch was observed in the blends containing initiators; this was shown by a reduction in the weight loss and more starch left in the samples after soil burial testing. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009
Synthesis, in‐vitro Microbial and Cytotoxic Studies of New Benzimidazole Derivatives
Authors: Harisha Reddy S. , Hosamani Kallappa M. , Keri Rangappa S.
Published: June 2009

Several new classes of benzimidazole derivatives were synthesized and evaluated for in‐vitro antimicrobial and cytotoxic activities. The results showed that all synthesized compounds exhibited moderate antimicrobial activity, and compounds 2, 4, and 13 displayed cytotoxic activity (as LD50) at the concentration 1×10–3 M against Artemia salina.
Effects of linear, ambient wind shear on simulated mammatus‐like clouds
Authors: Kanak Katharine M. , Straka Jerry M.
Published: June 2009

A suite of numerical experiments is conducted to extend our previous studies to explore the effects of linear, ambient wind shear on simulated mammatus‐like clouds. Increasing values of unidirectional shear result in banded cloud bases, and for the strongest shears roll‐type quasi‐two‐dimensional convection results rather than three‐dimensional lobe morphology. Two observed soundings were used, and the sounding with a drier, shallower sub‐cloud layer appeared to be most strongly affected by the presence of the ambient shear. The drier sounding also had less snow in the mammatus lobes owing to sublimation. Copyright © 2009 Royal Meteorological Society
Weitwinkel – Nahaufnahme: Zeitperspektiven in der Wissenschaftsgeschichte
Authors: Wahrig Bettina
Published: June 2009

Close‐Ups and Long Shots: Perspectives on Time in the History of Science. In the last decade, historians of science have shown a growing interest in the question of time. Especially when looking at the huge amount of valuable work performed within the methodological frames of microhistory, experimental and social history of science, the question has come up how to re‐integrate ‘longue‐durée‐perspectives’ into historiography of science. The Society for History of Science has dedicated its 45th symposion (1 to 3 Mai 2008) in Halle to this question. This introduction deals with the problems of different and may be incommensurable modes of ‘being‐in‐time’. How can different perspectives on time be combined, how can “close‐ups”, together with “long shots” (Gianna Pomata) make sense in the history of science? The quest for a narrative transporting the simultaneity of the non‐simultaneous, or, as Koselleck's “Zeitschichten” could be translated, of different layers of time, may start with a criticism of the homogeneous and empty time (Benjamin) and its colonizing connotations, or, with re‐examining historiographical concepts of discontinuity (e.g. scientific revolutions, breaks, eras and epochs) and their relationship to concepts of continuity. Recent accounts in the history of science have insisted on the non‐disposability (Unverfügbarkeit) of historical events, on their contingency. And this is possibly an effect of the different time‐structures of the objects of historiography.
Illuminating the host – How RNAi screens shed light on host‐pathogen interactions
Authors: Prudêncio Miguel , Lehmann Maik J.
Published: June 2009

Over millions of years pathogens have coevolved with their respective hosts utilizing host cell functions for survival and replication. Despite remarkable progress in developing antibiotics and vaccination strategies in the last century, infectious diseases still remain a severe threat to human health. Meanwhile, genomic research offers a new era of data‐generating platforms that will dramatically enhance our knowledge of pathogens and the diseases they cause. Improvements in gene knockdown studies by RNA interference (RNAi) combined with recent developments in instrumentation and image analysis enable the use of high‐throughput screening approaches to elucidate host gene functions exploited by pathogens. Although only a few RNAi‐based screens focusing on host genes have been reported so far, these studies have already uncovered hundreds of genes not previously known to be involved in pathogen infection. This review describes recent progress in RNAi screening approaches, highlighting both the limitations and the tremendous potential of RNAi‐based screens for the identification of essential host cell factors during infection.
Development of a system for the on‐line measurement of carbon dioxide production in microbioreactors: Application to aerobic batch cultivations of Candida utilis
Authors: van Leeuwen Michiel , Heijnen Joseph J. , Gardeniers Han , van der Wielen Luuk A. M. , van Gulik Walter M.
Published: June 2009

We developed and applied a conductometric method for the quantitative online measurement of the carbon dioxide (CO2) production during batch cultivations of Candida utilis on a 100‐μL scale. The applied method for the CO2 measurement consisted of absorption of the produced CO2 from the exhaust gas of the microbioreactor in an alkali solution, of which the conductivity was measured on‐line. The measured conductivity change of the alkali solution showed a linear relation with the total amount of CO2 absorbed. After calibration of the CO2 measurement system, it was connected to a well of a 96‐well microtiter plate. The mixing in the well was achieved by a magnetic stirrer. Using online measurement of the CO2 production during the cultivation, we show reproducible exponential batch growth of C. utilis on a 100‐μL scale. The CO2 production measurements obtained from the microcultivation were compared with the CO2 production measurement in a 4‐L bioreactor equipped with a conventional off‐gas analyzer. The measurements showed that on‐line measurement of the CO2 production rate in microbioreactors can provide essential data for quantitative physiological studies and provide better understanding of microscale cultivations. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Optimization of a whole‐cell cadmium sensor with a toggle gene circuit
Authors: Wu Cindy H. , Le David , Mulchandani Ashok , Chen Wilfred
Published: June 2009

This work demonstrates improvement of a whole‐cell cadmium detection sensor through construction of a gene circuit. A cadmium (II) specific regulatory promoter, PcadR, from Psuedomonas putida 06909, is used in the assembly of a toggle circuit. The circuit contains the cadR promoter fused to lacIq and gfp, and a divergently transcribed tac promoter and cadR. The toggle sensor exhibits lower background fluorescence, and a 20‐fold lower detection limit in comparison to a nontoggle gene circuit. The detection limit of the toggle sensor is 0.01 μM (1.12 ppb) cadmium chloride, and tunable with the addition of isopropyl‐b‐D‐thiogalactopyranoside (IPTG). The toggle sensor is highly specific to cadmium (II), and no response is elicited from zinc, lead, manganese, nickel, copper, and mercury. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009
Prevalence and predictors of antioxidant supplement use during breast cancer treatment
Authors: Greenlee Heather , Gammon Marilie D. , Abrahamson Page E. , Gaudet Mia M. , Terry Mary Beth , Hershman Dawn L. , Desai Manisha , Teitelbaum Susan L. , Neugut Alfred I. , Jacobson Judith S.
Published: June 2009

BACKGROUND.

Although many patients take antioxidant dietary supplements during breast cancer treatment, the benefits of such supplementation are unproven. The authors of this report analyzed the prevalence of and factors associated with antioxidant supplement use during breast cancer (BC) treatment among women who participated in the Long Island Breast Cancer Study Project.

METHODS.

From 2002 through 2004, women with BC who had participated a case‐control study from 1996 to 1997 were invited to participate in a follow‐up interview. Antioxidant supplement use was defined as any self‐reported intake of supplemental vitamin C, vitamin E, β‐carotene, or selenium in individual supplements or multivitamins.

RESULTS.

Follow‐up interview participants were younger, more predominantly white, and of higher socioeconomic status than women who did not respond. Among 764 participants who completed the follow‐up interview, 663 (86.8%) reported receiving adjuvant treatment for their BC. Of those 663 women, 401 (60.5%) reported using antioxidants during adjuvant treatment: One hundred twenty of 310 women (38.7%) used antioxidants during chemotherapy, 196 of 464 women (42.2%) used them during radiation, and 286 of 462 women (61.9%) used them during tamoxifen therapy. Of 401 antioxidant users, 278 women (69.3%) used high doses (doses higher than those contained in a Centrum multivitamin). The factors that were associated with high antioxidant supplement use during treatment were higher fruit and vegetable intake at diagnosis (relative risk [RR], 1.71; 95% confidence interval [CI], 1.13‐2.59), tamoxifen use (RR, 3.66; 95% CI, 2.32‐5.78), ever using herbal products (RR, 3.49; 95% CI, 2.26‐5.38), and ever engaging in mind‐body practices (RR, 1.72; 95% CI, 1.13‐2.64).

CONCLUSIONS.

Given the common use of antioxidant supplements during BC treatment, often at high doses and in conjunction with other complementary therapies, future research should address the effects of antioxidant supplementation on BC outcomes. Cancer 2009. © 2009 American Cancer Society.
Array comparative genomic hybridization identifies genetic regions associated with outcome in aggressive diffuse large B‐cell lymphomas
Authors: Robledo Cristina , García Juan L. , Caballero Dolores , Conde Eulogio , Arranz Reyes , Flores Teresa , Grande Carlos , Rodríguez José , García Eva , Sáez Ana I. , González Marcos , Gutiérrez Norma C. , Piris Miguel A. , Hernández Jesús M.
Published: June 2009

BACKGROUND:

Diffuse large B‐cell lymphomas (DLBCLs) are the most common type of non‐Hodgkin lymphomas. With chemotherapy and progenitor stem cell transplantation, about 60% of patients with DLBCL are long‐term survivors. The International Prognostic Index identifies patients with different outcomes. However, biologic characteristics also may help to discriminate different treatments groups.

METHODS:

DNA copy number changes identified by array comparative genomic hybridization (array‐CGH) were studied in 40 patients who had DLBCL with a poor prognosis and who were treated uniformly with dose‐escalated cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) and intensification before high‐dose chemotherapy with autologous stem cell transplantation.

RESULTS:

In total, 722 copy number changes were observed (median, 5 copy number changes per patient; range, 0‐75 copy number changes per patient), with a predominance of gains. Gains on 2p16 were present only in patients who failed to achieve a complete response after escalated CHOP therapy (P< .05). In univariate analysis, gains on 2p16 and losses on 17p13 (the tumor protein p53 geneTP53gene) were associated with a poor response to the therapy. Furthermore, age >60 years and losses on 10q23.31 (the phosphatase and tensin homolog genePTEN) or on 17p13 were associated with short survival. In multivariate analysis, only advanced age and losses on 10q23.31 retained an adverse prognostic impact.

CONCLUSIONS:

Array‐CGH identified multiple regions with common copy number changes, some of which were associated with outcome in patients with DLBCL. Cancer 2009. © 2009 American Cancer Society.
Risk of local recurrence after deltoid‐sparing resection for osteosarcoma of the proximal humerus
Authors: Gupta Giri R. , Yasko Alan W. , Lewis Valerae O. , Cannon Christopher P. , Raymond A. Kevin , Patel Shreyaskumar , Lin Patrick P.
Published: June 2009

BACKGROUND:

The anatomy of the shoulder poses special challenges with regard to limb‐sparing surgery. Resection of the deltoid muscle is considered by some surgeons to be necessary to achieve adequate margins for osteosarcoma of the proximal humerus. However, this can compromise the functional results after reconstruction of the shoulder. The goal of the current study was to determine whether deltoid‐sparing resection can be safely performed for osteosarcoma of the proximal humerus.

METHODS:

Between 1978 and 2005, 23 consecutive patients with high‐grade nonmetastatic osteosarcoma of the proximal humerus underwent limb‐sparing surgery with preservation of the deltoid muscle. All patients received neoadjuvant chemotherapy followed by surgery and postoperative chemotherapy. The mean follow‐up was 90 months (range, 7 months‐279 months).

RESULTS:

The overall survival at 5 years was 77%. At the time of last follow‐up, 14 (61%) of 23 of patients were alive without evidence of disease. Three (13%) patients developed local recurrence. Two of these patients had poor responses to chemotherapy, with tumor necrosis of 50% and 70%. The third patient had a pathologic fracture of the humerus. Positive surgical margins were associated with local recurrence, and 2 of 4 patients with a positive surgical margin developed local recurrence (P = .01).

CONCLUSIONS:

Preservation of the deltoid muscle can be performed for carefully selected patients with osteosarcoma of the proximal humerus. Routine use of the procedure is not justified, because it may be associated with an elevated risk of recurrence. The risk of local recurrence appears to be related to positive surgical margins and possibly the percentage of tumor necrosis. Cancer 2009. © 2009 American Cancer Society.
Influence of private practice setting and physician characteristics on the use of breast cancer adjuvant chemotherapy for elderly women
Authors: Hershman Dawn L. , Buono Donna , McBride Russell B. , Tsai Wei Yann , Neugut Alfred I.
Published: June 2009

BACKGROUND:

Although >70% of younger women with nonmetastatic breast cancer (BC) received adjuvant chemotherapy, only approximately 15% to 20% of elderly women with BC received chemotherapy. The decision to treat may be associated with nonmedical factors, such as patient, physician, or practice characteristics. In the current study, the association between oncologist characteristics and the receipt of chemotherapy in elderly women with BC was evaluated.

METHODS:

Women aged >65 years who were diagnosed with American Joint Committee on Cancer stages I to III BC between 1991 and 2002 were identified in the Surveillance, Epidemiology, and End Results‐Medicare database. The Physician Unique Identification Number was linked to the American Medical Association Masterfile to obtain information on oncologists. Investigated was the association between demographic, tumor, and oncologist‐related factors and the receipt of chemotherapy, using Generalized Estimating Equations to control for clustering. Patients were defined as low risk (estrogen/progesterone receptor positive, stage I/II disease) and high risk (estrogen/progesterone receptor‐negative, stage II/III disease).

RESULTS:

Of 42,544 women identified, 8714 (20%) were treated with adjuvant chemotherapy. In a hierarchical analysis, women who underwent chemotherapy were more likely be treated by oncologists primarily employed in a private practice (odds ratio [OR], 1.40; 95% confidence interval [95% CI], 1.23‐1.59) and who graduated after 1975 (OR, 1.12; 95% CI, 1.01‐1.26) and were less likely to have an oncologist trained in the United States (OR, 0.83; 95% CI, 0.74‐0.93). The association between a private practice setting and the receipt of chemotherapy was found to be similar for patients at high risk (OR, 1.55) and low risk (OR, 1.35) for cancer recurrence.

CONCLUSIONS:

Elderly women with BC treated by oncologists who were employed in a private practice were more likely to receive chemotherapy. Efforts to determine whether these associations reflected experience, practice setting, insurance type, or other economic incentives are warranted. Cancer 2009. Published 2009 by the American Cancer Society.
Free jet issuing from a pipe with a triangular collar: A numerical simulation
Authors: Shamami Kievan Khademi , Birouk Madjid
Published: June 2009

RANS closure models (Reynolds Stress Model, RSM, and the standard k–ε model) are tested in the present study for their ability to predict the mean features of a free turbulent round jet expanded into a triangular collar. Although the jet is turbulent and three dimensional, the predictions show that the RSM closure is able to nearly reproduce published experimental data. Copyright © 2009 John Wiley & Sons, Ltd.