bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of melt processing conditions on the morphology and properties of nylon 6 nanocomposites
Authors: Chavarria F. , Shah R.K. , Hunter D.L. , Paul D.R. 
Published: September 2007

AbstractNylon 6 (PA‐6) organoclay nanocomposites were prepared by melt processing using three different twin screw extruders (TSEs). The effect of mixing conditions, feed port location, residence time, and number of extrusion passes on the morphology and mechanical properties of the nanocomposites were examined. Wide‐angle X‐ray scattering, transmission electron microscopy (TEM), and mechanical property data are reported. Particle analyses were performed on the TEM images to quantitatively characterize the extent of exfoliation. The amount of shear and the mixing conditions created by TSEs have a significant effect on the morphology and properties of PA‐6 nanocomposites. Morphology and mechanical property results show that (1) melting the polymer before coming into contact with the organoclay followed by a low level of shear and (2) maintaining a medium level of shear throughout the extruder with a longer residence time lead to extremely high platelet dispersion and matrix reinforcement for PA‐6 nanocomposites. Nanocomposites formed in a DSM microcompounder showed similar morphologies and modulus trends as those obtained with conventional TSEs; thus, this microcompounder is a good alternative for nanocomposite research especially when only small amounts of material are available. POLYM. ENG. SCI., 47:1847–1864, 2007. © 2007 Society of Plastics Engineers
Comparison of vertical and horizontal slot die coatings
Authors: Chang Hsien‐Ming , Chang Yu‐Rong , Lin Chi‐Feng , Liu Ta‐Jo 
Published: September 2007

AbstractComparison of vertical and horizontal slot coatings was carried out experimentally using aqueous glycerin solutions with varying viscosity on a laboratory‐scale slot coater. The maximum coating speeds achieved in vertical slot coating were found to be higher than those of horizontal slot coating for low‐viscosity solutions. The coating defects observed below the minimum wet thickness changed from ribbing to air entrainment at a critical solution viscosity of around μ = 75 mPa s. Above this critical viscosity, a lower minimum wet thickness was obtained for the horizontal coating but not for vertical coating. The difference between vertical and horizontal coating was mainly the length of the coating bead. The dimensionless minimum wet thickness was correlated as a function of Reynolds number. There existed three regions of minimum wet thickness depending on Reynolds number. Initially, the dimensionless wet thickness increased in the low Reynolds number region (Region I), then reached a plateau in the intermediate Re region (Region II), finally dropped off sharply in the high Re region (Region III). The boundaries of these three regions were identified by two critical Reynolds numbers, i.e., Re = 1 and 20. Only Regions I and II of the wet thickness could be found for horizontal coating, while mainly Regions II and III were obtained for vertical coating, depending on the viscosity of the coating solution. POLYM. ENG. SCI., 47:1927–1936, 2007. © 2007 Society of Plastics Engineers
Analysis of gene expression in two human‐derived cell lines exposed in vitro to a 1.9 GHz pulse‐modulated radiofrequency field
Authors: Chauhan Vinita , Qutob Sami S. , Lui Stephanie , Mariampillai Anu , Bellier Pascale V. , Yauk Carole L. , Douglas George R. , Williams Andrew , McNamee James P. 
Published: September 2007

AbstractThere is considerable controversy surrounding the biological effects of radiofrequency (RF) fields, as emitted by mobile phones. Previous work from our laboratory has shown no effect related to the exposure of 1.9 GHz pulse‐modulated RF fields on the expression of 22 000 genes in a human glioblastoma‐derived cell‐line (U87MG) at 6 h following a 4 h RF field exposure period. As a follow‐up to this study, we have now examined the effect of RF field exposure on the possible expression of late onset genes in U87MG cells after a 24 h RF exposure period. In addition, a human monocyte‐derived cell‐line (Mono‐Mac‐6, MM6) was exposed to intermittent (5 min ON, 10 min OFF) RF fields for 6 h and then gene expression was assessed immediately after exposure and at 18 h postexposure. Both cell lines were exposed to 1.9 GHz pulse‐modulated RF fields for 6 or 24 h at specific absorption rates (SARs) of 0.1–10.0 W/kg. In support of our previous results, we found no evidence that nonthermal RF field exposure could alter gene expression in either cultured U87MG or MM6 cells, relative to nonirradiated control groups. However, exposure of both cell‐lines to heat‐shock conditions (43°C for 1 h) caused an alteration in the expression of a number of well‐characterized heat‐shock proteins.
Raman spectroelectrochemistry on SWNTs at higher doping levels: Evidence for a transition to intercalative doping
Authors: Rafailov P. M. , Thomsen C. , Dettlaf‐Weglikowska U. , Hornbostel B. , Roth S. 
Published: September 2007

AbstractWe studied the transition from the electrochemical double‐layer charging regime to intercalative doping of SWNT buckypaper in KCl aqueous solution. For this purpose we used doping levels by applying constant potentials above 1 V approaching and slightly exceeding the oxidation potential for Cl– ions. At each potential in situ Raman measurements of the radial breathing mode (RBM), the high‐energy tangential mode (HEM) and the disorder‐induced (D) mode were performed. From a comparative analysis of the Raman spectra we conclude that above 1 V a significant penetration of chlorine species into the interstitial channels of the SWNT bundles and possibly functionalization take place. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth mechanism of solution‐deposited layers of the charge‐transfer salt CuDDQ
Authors: Weitz Ralf Thomas , Rauschenbach Stephan , Forment‐Aliaga Alicia , Burghard Marko , Kern Klaus 
Published: September 2007

AbstractCharge‐transfer (CT) salts such as copper‐2,3‐dichloro‐5,6‐dicyano‐p ‐benzoquinone (CuDDQ) are promising components of reversible resistive memory switching devices. In the study presented here, we report on the composition of CuDDQ layers grown from acetonitrile containing solution onto copper‐coated silicon substrates. According to Rutherford Backscattering Spectrometry (RBS) experiments, the CuDDQ film is homogeneously composed of copper and DDQ across its whole thickness, and the ratio between copper and DDQ is 1:1. A complex between copper and acetonitrile has been identified by Electro Spray Ionization (ESI) time‐of‐flight mass spectrometry as the main source of copper ions for the CuDDQ layer formation. In contrast, if ethanol is used as solvent, no copper‐ethanol complex can be discerned from the ESI mass spectrum. This finding underlines the vital role of acetonitrile as the main copper source for the complexation reaction with DDQ. The continuous availability of the copper‐acetonitrile complex in solution during the growth of the CuDDQ layers explains their homogeneity as determined by RBS. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Optical properties of polymer films with embedded single‐wall carbon nanotubes
Authors: Chernov A. I. , Obraztsova E. D. , Lobach A. S. 
Published: September 2007

AbstractIn this work the thin polymer films (based on polyvinyl alcohol or carboxymetylcellulose) containing single‐wall carbon nanotubes synthesized by different methods have been fabricated by a novel technology and studied in detail by UV–VIS–NIR optical absorption and Raman scattering techniques. The films are prospective as an optical material with a high non‐linearity. This property allows using them as ultra‐fast saturable absorbers in different laser schemes, especially, in fiber lasers. The optical spectroscopy has been used for optimization of several film parameters: an optical density, a thickness, a level of scattered light and proximity of the film absorption bands to the operation wavelengths of different solid state lasers. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An evaluation of the growth of nitrides on semipolar substrates using two indicators
Authors: Gil Bernard , Bigenwald Pierre , Briot Olivier 
Published: September 2007

AbstractWe evaluate the properties of nitride heterostructures on semipolar substrates using two indicators: the cancellation of the Quantum Confined Stark Effect and the volume density of elastic energy stored in the strained layers of GaN–GaInN heterostructures lattice‐matched to (hkl)‐oriented GaN semipolar substrates. These two parameters indicate that the growth on specific orientations is a plus when compared to growth on (0001) polar substrates. We will show that, unfortunately, one cannot simultaneously minimize the stored elastic energy and cancel the Quantum Confined Stark Effect, but it is possible to significantly reduce both of them. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Tandem mass spectrometry acquisition approaches to enhance identification of protein‐protein interactions using low‐energy collision‐induced dissociative chemical crosslinking reagents
Authors: Soderblom Erik J. , Bobay Benjamin G. , Cavanagh John , Goshe Michael B. 
Published: September 2007

AbstractChemical crosslinking combined with mass spectrometry is a useful tool for studying the topological organization of multiprotein interactions, but it is technically challenging to identify peptides involved in a crosslink using tandem mass spectrometry (MS/MS) due to the presence of product ions originating from both peptides within the same crosslink. We have previously developed a novel set of collision‐induced dissociative chemical crosslinking reagents (CID‐CXL reagents) that incorporate a labile bond within the linker which readily dissociates at a single site under low‐energy collision‐induced dissociation (CID) to enable independent isolation and sequencing of the crosslinked peptides by traditional MS/MS and database searching. Alternative low‐energy CID events were developed within the in‐source region by increasing the multipole DC offset voltage (ISCID) or within the ion trap by increasing the collisional excitation (ITCID). Both dissociation events, each having their unique advantages, occur without significant backbone fragmentation to the peptides, thus permitting subsequent CID to be applied to these distinct peptide ions for generation of suitable product ion spectra for database searching. Each approach was developed and applied to a chemical crosslinking study involving the N‐terminal DNA‐binding domain of AbrB (AbrBN), a transition‐state regulator in Bacillus subtilis. A total of thirteen unique crosslinks were identified using the ITCID approach which represented a significant improvement over the eight unique crosslinks identified using the ISCID approach. The ability to segregate intrapeptide and interpeptide crosslinks using ITCID represents the first step towards high‐throughput analysis of protein‐protein crosslinks using our CID‐CXL reagents. Copyright © 2007 John Wiley & Sons, Ltd.
Influence of a 4‐aminomethylbenzoic acid residue on competitive fragmentation pathways during collision‐induced dissociation of metal‐cationized peptides
Authors: Osburn Sandra , Ochola Sila , Talaty Erach , Van Stipdonk Michael 
Published: September 2007

AbstractFormation of [bn + 17 + cat]+ is a prominent collision‐induced dissociation (CID) pathway for Li+‐ and Na+‐cationized peptides. Dissociation of protonated and Ag+‐cationized peptides instead favors formation of the rival b/[bn−1 + cat]+ species. In this study the influence of a 4‐aminomethylbenzoic acid (4AMBz) residue on the relative intensities of [b3−1 + cat]+ and [b3 + 17 + cat]+ fragment ions was investigated using several model tetrapeptides including those with the general formula A(4AMBz)AX and A(4AMBz)GX (where X = G, A, V). For Li+‐ and Na+‐cationized versions of the peptides there was a significant increase in the intensity of [b3−1 + cat]+ for the peptides that contain the 4AMBz residue, and in some cases the complete elimination of the [b3 + 17 + cat]+ pathway. The influence of the 4AMBz residue may be attributed to the fact that [b3−1 + cat]+ would be a highly conjugated species containing an aromatic ring substituent. Comparison of CID profiles generated from Na+‐cationized AAGV and A(4AMBz)GV suggests an apparent decrease in the critical energy for generation of [b3−1 + Na]+ relative to that of [b3 + 17 + Na]+ when the aromatic amino acid occupies a position such that it leads to the formation of the highly conjugated oxazolinone, thus leading to an increase in formation rate for the former compared to the latter. Copyright © 2007 John Wiley & Sons, Ltd.
Efficient enrichment and desalting of protein digests using magnetic mesocellular carbon foams in matrix‐assisted laser desorption/ionization mass spectrometry
Authors: Kim Young‐Pil , Cho Kun , Lee Dohoon , Piao Yunxian , Ahn Yeong Hee , Yoo Jong Shin , Hyun Taeghwan , Kim Hak‐Sung 
Published: September 2007

AbstractWe demonstrate that magnetic mesocellular carbon foams (Mag‐MCF‐C) can be effectively used for enrichment and desalting of protein digests or peptides in matrix‐assisted laser desorption/ionization mass spectrometry (MALDI‐MS). The large mesocellular pores and surface area of Mag‐MCF‐C are likely to mainly contribute to high efficiency in enrichment and desalting of protein digests. The magnetic property of Mag‐MCF‐C enabled easy and simple enrichment and desalting process comprising adsorption, washing, and separation steps by using an external magnet. Following elution from Mag‐MCF‐C by using a matrix solution (CHCA in 70% ACN/0.1% TFA), the peptides were subjected to MALDI‐MS analysis. As a result, MALDI mass spectra of peptides or tryptic protein digests were distinct even at a peptide concentration as low as 50 pM. The use of Mag‐MCF‐C resulted in significantly improved sequence coverage for protein identification when compared to other conventional methods. Mag‐MCF‐C will find applications in mass spectrometric analysis of low abundance peptides or protein digests with high sensitivity. Copyright © 2007 John Wiley & Sons, Ltd.
The Ecology of Adolescent Substance Abuse Service Utilization
Authors: Jones Diana L. , Heflinger Craig Anne , Saunders Robert C. 
Published: September 2007

AbstractThis paper presents an ecological‐community model toward the explanation of variation in patterns of substance abuse (SA) service utilization among adolescents who are enrolled in Tennesssee's Medicaid program (TennCare). Guided by a theoretical framework that draws from the social ecology work of Bronfenbrenner and health services utilization models promoted by Aday and Andersen, we apply a social indicators approach toward explaining the impact of community ecology on identification of SA and treatment engagement. Both county‐level rates and individual‐level treatment utilization are examined and hierarchical linear modeling is incorporated to examine the individual‐in‐community phenomenon. This study is an expansion of previous service utilization research and suggests that explanations of youth's service utilization must necessarily include not only individual, familial, and service system characteristics, but community factors, as well.
Metabolic and cardiovascular changes in women with polycystic ovary syndrome
Authors: Meden‐Vrtovec H. , Vrtovec B. , Osredkar J. 
Published: September 2007

AbstractObjectiveTo analyze the relationship between QTc interval and cardiovascular risk factors in women with polycystic ovary syndrome (PCOS).MethodsStudy group included 119 PCOS women (age: 32.2 ±5.2 years) and the control group 64 age‐matched healthy women; they all underwent QT interval measurement, and plasma levels of high‐sensitivity CRP (hsCRP), endothelin‐1 (ET1), insulin, and testosterone determinations.ResultsIn PCOS women hsCRP (2.35 ± 2.14 mg/L vs. 1.01 ± 1.28 mg/L; P = 0.04), ET1 (23.6 ± 10.3 ng/L vs. 7.7 ± 15.9 ng/L; P = 0.01), and insulin (16.5 ± 7.8 mIU/L vs. 11.8 ±10.7 mIU/L; P = 0.03) levels were significantly higher, and QTc interval significantly shorter than in controls (401 ± 61 ms vs. 467 ± 61 ms; P = 0.007). In 67 (56%) PCOS patients with a short QTc interval (< 400 ms), plasma testosterone levels were significantly higher than in PCOS women with normal QTc interval (2.3 ± 2.1 nmol/L vs. 1.4 ± 1.7 nmol/L; P = 0.02).ConclusionsIn patients with polycystic ovary syndrome increased testosterone levels may attenuate the effects of coronary risk factors.
The challenges of improving emergency obstetric care in two rural districts in Mali
Authors: Otchere S.A. , Kayo A. 
Published: September 2007

AbstractObjectiveWe describe a collaboration between Save the Children USA, the Averting Maternal Death and Disability (AMDD) program and the Ministry of Health of Mali, to improve the availability, quality and utilization of emergency obstetric care (EmOC) in Yanfolila and Bougouni rural districts in Sikasso Region of Mali.MethodsProject planning, interventions and strategies between 2001 and 2004 were aimed at improving the capacity of 2 district hospitals to provide quality EmOC, sensitizing the community as partners to use services and to influence changes in policy at a national level through advocacy efforts.ResultsBy the end of 2004, despite many health systems’ challenges, the 2 hospitals were providing comprehensive EmOC. Providing 24‐hour service proved difficult and, though not effectively institutionalized in the 2 hospitals, the UN Process Indicators showed modest improvements in quality and utilization of EmOC. Met need for EmOC increased from 9% in 2001 to 15% in 2004 in Bougouni and from 6% in 2001 to 15% in 2004 in Yanfolila. Case fatality rates declined by 69% (from 7% in 2001 to 2% in 2004) and by 38% (from 8% in 2001 to 5% in 2004) in Bougouni and Yanfolila, respectively.DiscussionAlthough useful policy changes were achieved at the national level, more are needed if UN Guidelines are to be met. Availability of more obstetric functions at the community level, and fewer staff transfers are among policy changes needed.ConclusionSave the Children's project experience showed that it is possible to improve the quality and use of EmOC in hospitals despite challenges; we drew national attention to EmOC as a key strategy in maternal mortality reduction, and raised awareness of the need for improved EmOC services at clinics that are more accessible to the community.
Evaluation of health workers' training in use of the partogram
Authors: Fatusi A.O. , Makinde O.N. , Adeyemi A.B. , Orji E.O. , Onwudiegwu U. 
Published: September 2007

AbstractObjectiveTo assess the impact of training on use of the partogram for labor monitoring among various categories of primary health care workers.MethodsFifty‐six health workers offering delivery services in primary health care facilities were trained to use the partogram and were evaluated after 7 months.ResultsA total of 242 partograms of women in labor were plotted over a 1‐year period; 76.9% of them were correctly plotted. Community health extension workers (CHEWs) plotted 193 (79.8%) partograms and nurse/midwives plotted 49 (20.2%). Inappropriate action based on the partogram occurred in 6.6%. No statistically significant difference was recorded in the rate of correct plotting and consequent decision‐making between nurse/midwives and the CHEWs.ConclusionLower cadres of primary health care workers can be effectively trained to use the partogram with satisfactory results, and thus contribute towards improved maternal outcomes in developing countries with scarcity of skilled attendants.
Breed differences in mucosal and systemic antibody response to nematode infection in sheep: an important role for IgE?
Authors: SAYERS G. , GOOD B. , HANRAHAN J. P. , O'DONOVAN J. , MULCAHY G. , SWEENEY T. 
Published: September 2007

SUMMARYThis study compared the immunological and biochemical responses of co-grazed Suffolk and Texel lambs to a natural gastrointestinal nematode infection. Variables analysed included serum pepsinogen, total protein, albumin, haematological variables and nematode-specific serum immunoglobulin activity, at 11, 14 and 17 weeks of age. At 17 weeks, randomly selected lambs were necropsied to determine worm burdens, nematode-specific mucosal abomasal and intestinal immunoglobulin activity. Nematode burden, faecal egg count and pepsinogen concentrations were significantly higher in Suffolks relative to Texels, at all 3 time-points investigated. Suffolks displayed significantly higher erythrocyte, total leukocyte, lymphocyte and neutrophil counts, mean cell volume and packed cell volume, than Texels (P<0·01). However, breed differences in eosinophil counts were not significant. While serum nematode-specific antibody activity levels were significantly higher (P<0·001) in Texels for all isotypes measured, antibody activity levels at a mucosal level were equivalent in both breeds. Correlation analysis of mucosal antibody levels and nematode variables highlighted a more consistent pattern of events in Texels, with more mucosal antibodies negatively correlated with FEC and worm burden, in comparison to Suffolks. In particular, an important role for mucosal IgE is proposed. In Texels, a significant and negative correlation was identified between IgE and faecal egg counts and worm burden (FEC: −0·48, P<0·005). This was not observed in Suffolks. The evidence suggests that susceptibility in Suffolks may be mediated through poor IgE affinity/avidity and/or through deficiencies in related mechanisms such as mast cell production, recruitment or activation.
O(n) mass matrix inversion for serial manipulators and polypeptide chains using Lie derivatives
Authors: Lee Kiju , Wang Yunfeng , Chirikjian Gregory S. 
Published: September 2007

SUMMARYOver the past several decades, a number of O(n) methods for forward and inverse dynamics computations have been developed in the multibody dynamics and robotics literature. A method was developed by Fixman in 1974 for O(n) computation of the mass-matrix determinant for a serial polymer chain consisting of point masses. In other of our recent papers, we extended this method in order to compute the inverse of the mass matrix for serial chains consisting of point masses. In the present paper, we extend these ideas further and address the case of serial chains composed of rigid-bodies. This requires the use of relatively deep mathematics associated with the rotation group, SO(3), and the special Euclidean group, SE(3), and specifically, it requires that one differentiates real-valued functions of Lie-group-valued argument.
Legislating for a Market Economy in China
Authors: Clarke Donald C. 
Published: September 2007

AbstractSince the early 1990s, China has come a long way in legislating the foundational rules for its reformed economy. Virtually all of the important areas – contracts, business organizations, securities, bankruptcy and secured transactions, to name a few – are now covered by national legislation as well as lower-level regulations. Yet an important feature of a legal structure suited to a market economy is missing: the ability of the system to generate from below solutions to problems not adequately dealt with by existing legislation. The top-down model that has dominated Chinese law reform efforts to date can only do so much. What is needed now is a more welcoming attitude to market-generated solutions to the gaps and other problems that will invariably exist in legislation. The state's distrust of civil-society institutions and other bottom-up initiatives suggests, however, that this different approach will not come easily.