bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fundamental studies on wood–plastic composites: Effects of fiber concentration and mixing temperature on the mechanical properties of poplar/PP composite
Authors: Nourbakhsh Amir , Ashori Alireza 
Published: March 2008

AbstractWood fibers are increasingly being used as reinforcement in commercial thermoplastic composites due to their low cost, high specific properties and renewable nature. The ultimate goal of our research was to find a fundamental understanding of the mechanical behavior of poplar/polypropylene (PP) composites. The effect of wood fiber concentrations and mixing temperature on the mechanical properties of composites, prepared by using MAPP as the coupling agent, was investigated. In the sample preparation, four levels of fiber loading (10, 20, 30, and 40 wt%) and three compounding temperatures (180, 190, and 200oC) were used. Most major changes in composite performance occurred at fiber contents above 30%. The results clearly showed that the fiber loading of 30 and 40 wt% at 190oC was provided adequate reinforcement to increase the tensile and flexural strength of the PP powder. The modulus also increased with increasing the fiber content, because poplar fibers are believed to be more rigid than polymer. However the addition of wood fibers resulted in a decrease in elongation and impact properties of the composites. The FTIR spectroscopy showed that the copolymer was bonded to the fibers by ester linkages and hydrogen bonds at 1705–1735 cm−1. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers
Electrical conductivity and microwave absorbing properties of nickel‐coated multiwalled carbon nanotubes/poly(phthalazinone ether sulfone ketone)s composites
Authors: Feng Xuebin , Liao Gongxiong , Du Jinhong , Dong Liming , Jin Kejia , Jian Xigao 
Published: March 2008

AbstractNickel‐coated multiwalled carbon nanotubes (Ni‐MWNT) were prepared by electroless deposition with ultrasonic vibrations. The morphologies and components were characterized by scanning electron microscope and energy dispersive spectroscopy. Two types of fillers, multiwalled carbon nanotubes (MWNT) and Ni‐MWNT, were blended with poly(phthalazinone ether sulfone ketone)s (PPESK) by the solution‐mixing method, respectively. The electrical conductivity and microwave absorbing properties of the composites were investigated. The results show that Ni‐MWNT/PPESK composites have relatively lower electrical resistivity values than MWNT/PPESK, and in both cases the decrease in electrical resistivity indicates a similar percolation transition behavior in the same MWNT content region. Moreover, as MWNT loading is 5 parts per hundred parts of resin (phr), Ni‐MWNT/PPESK composite has the wider frequency region (9.5–13.5 GHz) of the reflection loss (RL) less than −10 dB and the lower minimum value of RL (−27.5 dB) compared with MWNT/PPESK. The better microwave absorption properties can be attributed to the improved dielectric and magnetic properties of the fillers. A good correlation between electrical conductivity and microwave absorption was found for MWNT/PPESK composites. In addition, tensile test and thermogravimetric analysis indicate that introducing Ni‐MWNT into PPESK is favorable for the improvement of the mechanical properties and high temperature stability of the composites. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers
A “click” approach to ROMP block copolymers
Authors: Hilf Stefan , Hanik Nils , Kilbinger Andreas F. M. 
Published: March 2008

AbstractAmphiphilic block copolymers can be conveniently prepared via convergent syntheses, allowing each individual polymer block to be prepared via the polymerization technique that gives the best architectural control. The convergent “click‐chemistry” route presented here, gives access to amphiphilic diblock copolymers prepared from a ring opening metathesis polymer and polyethylene glycol. Because of the high functional group tolerance of ruthenium carbene initiators, highly functional ring opening metathesis polymerization (ROMP) polymer blocks can be prepared. The described synthetic route allows the conjugation of these polymer blocks with other end‐functional polymers to give well‐defined and highly functional amphiphilic diblock copolymers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2913–2921, 2008
Synthesis and liquid crystalline properties of poly(1‐alkyne)s carrying triphenylene discogens
Authors: Xing Changmin , Lam Jacky W. Y. , Zhao Keqing , Tang Ben Zhong 
Published: March 2008

AbstractTriphenylene‐containing 1‐decynes with different alkyl chain lengths and their polymers are synthesized and the effects of the structural variables on their mesomorphic properties are investigated. The monomers [HCC(CH2)8CO2C18H6 (OCmH2m+1)5; m = 4–9] are prepared by consecutive etherization, coupling, and esterification reactions. The monomers form columnar phases at room temperature. The polymerizations of the monomers are effected by [Rh(nbd)Cl]2, producing soluble polymers in high yields (up to 84%). The structures and properties of the polymers are characterized and evaluated by IR, NMR, TGA, DSC, POM, and XRD analyses. All the polymers are thermally stable, losing little of their weights when heated to 300 °C. The isotropization temperature of the polymers increases initially with the length of alkyl chain but decreases on further extension. Although the polymers with shorter and longer alkyl chain lengths adopt a homogeneous hexagonal columnar structure, those with intermediate ones form mesophases with mixed structures. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2960–2974, 2008
Preparation and chemical properties of soluble π‐conjugated poly(aryleneethynylene) consisting of azabenzothiadiazole as the electron‐accepting unit
Authors: Fukumoto Hiroki , Yamamoto Takakazu 
Published: March 2008

AbstractA soluble charge‐transfer type poly(aryleneethynylene), PAE‐AzaBzTdz, consisting of a highly electron‐accepting azabenzothiadiazole unit was prepared in 99% yield by palladium‐catalyzed polycondensation between 4,7‐dibromo‐2,1,3‐azabenzothiadiazole (Br2‐AzaBzTdz) and 1,4‐diethynyl‐2,5‐didodecyloxybenzene. PAE‐AzaBzTdz showed a number‐average molecular weight, Mn, of 6000 in gel‐permeation chromatography analysis and had good thermal stability as measured by TGA. UV–vis spectrum of PAE‐AzaBzTdz exhibited an absorption peak at 529 nm in chloroform, and the absorption peak shifted to a longer wavelength (601 nm) in film. Addition of MeOH to a CHCl3 solution of PAE‐AzaBzTdz led to aggregation of the polymer to form stable colloidal particles. Results of filtration experiments using 0.2 and 0.02 μm membranes supported aggregation of the polymer. Addition of trifluoroacetic acid (TFA) to a chloroform solution of PAE‐AzaBzTdz led to a red‐shift of the UV–vis peak from 529 to 640 nm. An X‐ray diffraction pattern of powdery PAE‐AzaBzTdz indicated that the polymer assumed a layer‐to‐layer stacked structure with an interlayer distance of 3.4 Å in the solid state. An X‐ray diffraction pattern of cast film of PAE‐AzaBzTdz revealed that the polymer molecules in the cast film were ordered on the surface of Pt plate with the dodecyl side chain oriented toward the surface of the Pt plate. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 2975–2982, 2008
Near‐infrared electroluminescence from fluorene‐based copolymers
Authors: Sun Mingliang , Jiang Xi , Wang Li , He Chao , Du Bin , Yang Renqiang , Cao Yong 
Published: March 2008

AbstractA series of random low band‐gap conjugated copolymers (PFO‐DDTQ) derived from 9,9‐dioctylfluorene (DOF) and 6,7‐dimethyl‐4,9‐di(4‐hexylthien‐2‐yl)‐[1,2,5]thiadiazolo[3,4‐g]quinoxalines (DDTQ) are prepared by the palladium‐catalyzed Suzuki coupling reaction. The obtained polymers are readily soluble in common organic solvents. The thin solid films of the polymers absorb light from 300 to 840 nm with two absorbance peaks at around 380 and 710 nm. Electroluminescent peaks are between 0.8 and 0.9 μm based on the polymers. The maximal external quantum efficiency reaches 0.30% with the emission peak at 824 nm from PFO‐DDTQ1 based devices. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3007–3013, 2008
Compliance in cystic fibrosis: An examination of infection control guidelines
Authors: Masterson Tracy , Wildman Beth G. , Newberry Benjamin , Omlor Gregory , Bryson Elizabeth , Kukay Ann 
Published: March 2008

AbstractThe goal of this research was to begin the process of evaluating acceptability of infection control (IC) recommendations to CF patients and their families, determine whether compliance with IC guidelines differs from compliance with traditional CF medical treatment with respect to the variables predictive of compliance, and assess which patients are most likely to comply with IC recommendations. Participants were recruited during routine outpatient visits at a regional CF center located in a pediatric hospital. The sample included 44 child and adolescent patients, aged 9–18 years and their guardian, and 27 adult patients. All patients completed questionnaires and interviews. Results of this preliminary study suggest that many individuals with CF are unaware of or unconcerned with the risks involved in infection transmission via social contact with other CF patients. Further, most participants reported that they could benefit from friendships with other CF patients. Health belief variables were found to be predictive of compliance with both IC guidelines and traditional medical treatments in the adult and parent sample, but not in the child sample. Possible explanations for study findings are discussed and recommendations for future research on IC compliance are highlighted. Pediatr Pulmonol. 2008; 43:435–442. © 2008 Wiley‐Liss, Inc.
Inactivation of the NF2 tumor suppressor protein merlin in DU145 prostate cancer cells
Authors: Horiguchi Akio , Zheng Rong , Shen Ruoqian , Nanus David M. 
Published: March 2008

AbstractBACKGROUNDThe neurofibromatosis 2 (NF2) tumor suppressor gene product merlin is an important regulator of contact‐dependent cell proliferation. Phosphorylation of merlin at serine 518 (Ser518) by the Rac effector p21‐activated kinase (PAK) inactivates merlin's growth suppressing function, and is regulated by cell‐culture conditions, including cell density, cell/substrate attachment, and growth factor availability. We examined the regulation of merlin expression and merlin phosphorylation in prostate cancer cells.METHODSPhosphorylation of merlin in five prostate cancer cell lines (LNCaP, DU145, PC3, 22RV1, and LAPC‐4) was examined by Western blotting using anti‐phospho‐merlin (Ser518) antibody. The activity of PAK, an upstream regulator of merlin phosphorylation, was measured by Western blotting using phospho‐PAK (Ser141) antibody. The effects of various cell‐culture conditions on the phosphorylation levels of merlin and PAK were analyzed.RESULTSBoth merlin expression and phosphorylation were low in LNCaP, PC3, 22RV1, and LAPC‐4 prostate cancer cells. In DU145 cells, total and phosphorylated merlin were abundant, but phosphorylation was not inhibited by high cell density, serum withdrawal, the addition of hyaluronic acid or inhibition of CD44 expression, all of which are reported to inhibit merlin phosphorylation in non‐neoplastic cells. PAK activation was elevated in DU145 cells and the addition of a PAK‐specific inhibitor peptide but not the Rac1‐specific inhibitor NSC23766 inhibited both PAK and merlin phosphorylation.CONCLUSIONSMerlin is inactivated in DU145 prostate cancer cells by PAK‐mediated constitutive phosphorylation, identifying a novel mechanism of merlin inactivation in neoplastic cells. Prostate 68:975–984, 2008. © 2008 Wiley‐Liss, Inc.
Recovery of bipedal locomotion in bonnet macaques after spinal cord injury: Footprint analysis
Authors: Babu R. Suresh , Namasivayam A. 
Published: March 2008

AbstractAnalysis of the recovery of gait after spinal cord injury has been widely demonstrated in rat and cat models using different behavioral tests and scoring systems. The present investigation was aimed to quantitatively analyze the degree of functional recovery in bipedal locomotion of bonnet macaques after inflicting spinal cord hemisection lesion. To measure the degree of locomotor recovery, we recorded four gait variables, viz., tip of opposite foot (TOF), print length (PL), toe spread (TS), and intermediary toes (IT) using a footprint analyzing technique. Monkeys were trained preoperatively to perform the monopedal hop or bipedal locomotion on runways. Footprints of trained monkeys were recorded using the nontoxic ink and white paper before and after surgery. Surgical hemisection was induced unilaterally in the right side of spinal cord at T12‐L1 level of trained monkeys. In hemiplegic monkeys, initially there was a substantial decrease in TOF and PL variables of the paretic limb, which then gradually increased for longer duration and reached the near presurgical values by the 7th and 5th postoperative month, respectively. In contrast to TOF and PL, the recovery of TS and IT variables was quicker, which dramatically increased at first and then slowly recovered to levels not significantly different from the corresponding preoperative values by the 4th postoperative month. The nonparetic limb has also showed mild alterations in all footprint variables but reached the normal values much faster compared to the paretic limb. The alterations in footprint variables of hemiplegic monkeys were examined for a postoperative period of up to 1 year. The findings of this study suggest that the mechanisms underlying locomotor recovery of lesioned macaques may be correlated to the mature function of spinal pattern generator for locomotion under the impact of residual descending and afferent connections. Further, this study also indicates the functional contribution of progressive strengthening of undamaged nerve fibers through a collateral sprouts/synaptic plasticity formed in partially lesioned cord of macaques. Synapse 62:432–447, 2008. © 2008 Wiley‐Liss, Inc.
Dynorphin and prodynorphin mRNA changes in the striatum during nicotine withdrawal
Authors: Isola Raffaella , Zhang Hailing , Tejwani Gopi A. , Neff Norton H. , Hadjiconstantinou Maria 
Published: March 2008

AbstractNicotine withdrawal causes somatic and negative affective symptoms that contribute to relapse and continued tobacco smoking. So far, the neuronal substrates involved are not fully understood, and an opioid role has been suggested. In this regard, the opioid dynorphin (Dyn) is of interest as it produces aversive states and has been speculated to play a role in the nicotine behavioral syndrome. These studies explore whether Dyn metabolism is altered during withdrawal following chronic administration of nicotine. Mice were administered nicotine, 2 mg/kg, s.c., four times daily for 14 days, and Dyn and prodynorphin (PD) mRNA estimated in selective brain regions at various times (30 min to 96 h) following drug discontinuation. The content of Dyn, estimated by RIA, was decreased in the striatum for a protracted time, from 30 min to over 72 h. In contrast, the mRNA for PD, evaluated by Northern blot, was elevated, appearing by 8 h and lasting over 96 h. Dyn was decreased in both ventral and dorsal striatum, and PD mRNA was differentially increased in the two striatal compartments as demonstrated by in situ hybridization. PD message was predominantly augmented in the nucleus accumbens, rostral pole, core, and shell, and the medial aspects of caudate/putamen. We interpret these data to indicate increased activity of striatal, particularly accumbal, dynorphinergic neurons during nicotine withdrawal resulting in enhanced peptide release and compensatory synthesis. Heightened dynorphinergic tone might be responsible, in part, for the emergence of the negative affective states observed during nicotine withdrawal. Synapse 62:448–455, 2008. © 2008 Wiley‐Liss, Inc.
The in vivo genotoxic effects of carvacrol and thymol in rat bone marrow cells
Authors: Azirak Sebile , Rencuzogullari Eyyup 
Published: March 2008

AbstractThe aim of this study was to investigate the in vivo genotoxic effects of carvacrol and thymol in bone marrow cells of rats. In the present study, both carvacrol (10, 30, 50, and 70 mg/kg b.w.) and thymol (40, 60, 80, and 100 mg/kg b.w.) significantly induced the structural and total chromosome abnormalities (CA) for all treatment periods (6, 12, and 24 h) when compared with control in bone marrow cells of rats intraperitonally administered. Both carvacrol and thymol showed similar effects with the positive control urethane on induction of the percentage of structural and total CA at the highest concentrations except the effects of carvacrol for 6 h treatment (70 mg/kg b.w. and 100 mg/kg b.w., respectively). In addition, carvacrol induced the numerical CA at all concentrations when compared to control and at two highest concentrations (50 and 70 mg/kg b.w.) when compared to solvent control. Thymol also induced the numerical CA especially at the highest concentration (100 mg/kg b.w.) for all treatment periods. It was shown that there was a dose‐dependent effect on induction of structural, numerical and total CA for both carvacrol and thymol. Carvacrol and thymol decreased the mitotic index (MI) in all the concentrations and treatment times when compared with control. Carvacrol showed the similar effects with EC on decreasing the MI at 70 mg/kg b.w. for 6 h, at 30 and 50 mg/kg b.w. for 12 h and at all concentrations for 24 h treatment periods. Thymol also showed a similar effect with urethane (ethyl carbamate, EC) on decreasing the MI at 60, 80, and 100 mg/kg b.w. for 6 h and at all concentrations for 24 h treatment periods. Test substances decreased the MI in a dose‐dependent manner. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2008.
Genetic factors influencing alcohol dependence
Authors: Mayfield R D , Harris R A , Schuckit M A 
Published: March 2008

Plentiful data from both animal and human studies support the importance of genetic influences in substance abuse and dependence (Bierut et al., 1998; Tsuang et al., 1998; Kendler et al., 2003). This review summarizes the evidence supporting such genetic influences, places them into perspective regarding animal and human studies, discusses the importance of both genes and environment, and highlights some specific genes of interest regarding the vulnerabilities for problems associated with alcohol use disorders. A long history of repetitive heavy use of alcohol exists across generations as well as the high prevalence of alcohol‐related problems in Western societies. Moreover, the information offered here addresses the importance of more general issues regarding genetics and gene expression related to alcohol abuse and dependence.British Journal of Pharmacology (2008) 154, 275–287; doi:fn1; published online 24 March 2008
Treatment with DF 2162, a non‐competitive allosteric inhibitor of CXCR1/2, diminishes neutrophil influx and inflammatory hypernociception in mice
Authors: Cunha T M , Barsante M M , Guerrero A T , Verri W A , Ferreira S H , Coelho F M , Bertini R , Di Giacinto C , Allegretti M , Cunha F Q , Teixeira M M 
Published: March 2008

Background and purpose:Neutrophil migration into tissues is involved in the genesis of inflammatory pain. Here, we addressed the hypothesis that the effect of CXC chemokines on CXCR1/2 is important to induce neutrophil migration and inflammatory hypernociception.Experimental approach:Mice were treated with a non‐competitive allosteric inhibitor of CXCR1/2, DF 2162, and neutrophil influx and inflammatory hypernociception were assessed by myeloperoxidase assay and electronic pressure meter test, respectively, in various models of inflammation.Key results:DF 2162 inhibited neutrophil chemotaxis induced by CXCR1/2 ligands but had no effect on CXCL8 binding to neutrophils. A single mutation of the allosteric site at CXCR1 abrogated the inhibitory effect of DF 2162 on CXCL‐8‐induced chemotaxis. Treatment with DF 2162 prevented influx of neutrophils and inflammatory hypernociception induced by CXCL1 in a dose‐dependent manner. The compound inhibited neutrophil influx and inflammatory hypernociception induced by carrageenan, lipopolysaccharide and zymosan, but not hypernociception induced by dopamine and PGE2. DF 2162 had a synergistic effect with indomethacin or the absence of TNFR1 to abrogate carrageenan‐induced hypernociception. Treatment with DF 2162 diminished neutrophil influx, oedema formation, disease score and hypernociception in collagen‐induced arthritis.Conclusions and implications:CXCR1/2 mediates neutrophil migration and is involved in the cascade of events leading to inflammatory hypernociception. In addition to modifying fundamental pathological processes, non‐competitive allosteric inhibitors of CXCR1/2 may have the additional benefit of providing partial relief for pain and, hence, may be a valid therapeutic target for further studies aimed at the development of new drugs for the treatment of rheumatoid arthritis.British Journal of Pharmacology (2008) 154, 460–470; doi:10.1038/bjp.2008.94; published online 24 March 2008
Different Types of Postpartum Luteal Activity Affected by the Exposure of Heat Stress and Subsequent Reproductive Performance in Holstein Lactating Cows
Authors: Kornmatitsuk B , Chantaraprateep P , Kornmatitsuk S , Kindahl H 
Published: March 2008

ContentsThe aim of the present study was to determine the effect of heat stress on postpartum (PP) luteal activity and subsequent reproductive performance in lactating cows. Thirty Holstein–Friesian (HF, ≥75%) cows (hot season, n = 15 and cool season, n = 15) were studied over 60 days after calving. The changes of temperature‐humidity index (THI) were monitored within both seasons. Body condition scores (BCS), uterine involution and the ovarian structures were recorded. Plasma samples were obtained three times a week for the analysis of progesterone (P4) and prostaglandin F2α metabolite (PG metabolite). Subsequent reproductive performance of the cows, calved within the same period was also evaluated. The means of THI for hot and cool seasons varied between 84–87 and 78–83 respectively. A drop of the mean BCS was recorded at 5 weeks PP in the cows during hot season (p < 0.01), however a delay of uterine involution during early PP period in hot season was not clearly seen. The cows with normal PP ovarian cyclicity during hot and cool seasons were 4/15 (26.7%) and 9/15 (60.0%) respectively. A higher percentage of abnormal luteal activity was found in the cows during hot season (p = 0.07) and delayed luteal cyclicity/anovulation was the most pronounced atypical P4 profile. The levels of PG metabolite were not different between groups and the relationship between the levels of PG metabolite and the time of uterine involution was not evident (p > 0.05). The heat detection rates and the pregnancy rates were higher in the cows during cool season (p < 0.05). Additionally, the higher first AI conception rates during cool season were recorded (p = 0.06). In conclusion, heat stress conditions had negative effects on BCS and altered a normal process of ovarian resumption PP, consequently resulted in lower reproductive performance in a tropical dairy herd.