bluuebunny/crossref_metadata_2025 huggingface dataset:
Longpath DOAS observations of surface BrO at Summit, Greenland
Authors: Stutz J. , Thomas J. L. , Hurlock S. C. , Schneider M. , von Glasow R. , Piot M. , Gorham K. , Burkhart J. F. , Ziemba L. , Dibb J. E. , Lefer B. L.
Published: February 2011

Abstract. Reactive halogens, and in particular bromine oxide (BrO), have frequently been observed in regions with large halide reservoirs, for example during bromine catalyzed coastal polar ozone depletion events. Much less is known about the presence and impact of reactive halogens in areas without obvious halide reservoirs, such as the polar ice sheets or continental snow. We report the first LP-DOAS measurements of BrO at Summit research station in the center of the Greenland ice sheet at an altitude of 3200 m. BrO mixing ratios in May 2007 and June 2008 were typically between 1–3 pmol mol−1, with maxima of up to 5 pmol mol−1. These measurements unequivocally show that halogen chemistry is occurring in the remote Arctic, far from known bromine reservoirs, such as the ocean. During periods when FLEXPART retroplumes show that airmasses resided on the Greenland ice sheet for 3 or more days, BrO exhibits a clear diurnal variation, with peak mixing ratios of up to 3 pmol mol−1 in the morning and at night. The diurnal cycle of BrO can be explained by a changing boundary layer height combined with photochemical formation of reactive bromine driven by solar radiation at the snow surface. The shallow stable boundary in the morning and night leads to an accumulation of BrO at the surface, leading to elevated BrO despite the expected smaller release from the snowpack during these times of low solar radiation. During the day when photolytic formation of reactive bromine is expected to be highest, efficient mixing into a deeper neutral boundary layer leads to lower BrO mixing ratios than during mornings and nights. The extended period of contact with the Greenland snowpack combined with the diurnal profile of BrO, modulated by boundary layer height, suggests that photochemistry in the snow is a significant source of BrO measured at Summit during the 2008 experiment. In addition, a rapid transport event on 4 July 2008, during which marine air from the Greenland coast was rapidly transported to Summit, led to enhanced mixing ratios of BrO and a number of marine tracers. However, marine transport events are rare and most likely not the main source of bromide in surface snow at Summit. The observed levels of BrO are predicted to influence NOx chemistry as well as impact HOx partitioning. However, impact of local snow photochemistry on HOx is smaller than previously suggested for Summit.
Interpreting methane variations in the past two decades using measurements of CH4 mixing ratio and isotopic composition
Authors: Monteil G. , Houweling S. , Dlugockenky E. J. , Maenhout G. , Vaughn B. H. , White J. W. C. , Rockmann T.
Published: February 2011

Abstract. The availability δ13C-CH4 measurements from atmospheric samples has significantly improved in recent years, which allows the construction of time series spanning up to about 2 decades. We have used these measurements to investigate the cause of the methane growth rate decline since 1980, with a special focus on the period 1998–2006 when the methane growth came to a halt. The constraints provided by the CH4 and δ13C-CH4 measurements are used to construct hypothetic source and sink scenarios, which are translated into corresponding atmospheric concentrations using the atmospheric transport model TM3 for evaluation against the measurements. The base scenario, composed of anthropogenic emissions according to Edgar 4, constant emissions from natural sources, and a constant atmospheric lifetime, overestimates the observed global growth rates of CH4 and δ13C-CH4 by, respectively, 10 ppb yr−1 and 0.02‰ yr−1 after the year 2000. It proves difficult to repair this inconsistency by modifying trends in emissions only, notably because a temporary reduction of isotopically light sources, such as natural wetlands, leads to a further increase of δ13C-CH4. Furthermore, our results are difficult to reconcile with the estimated increase of 5 Tg CH4 yr−1 in emissions from fossil fuel use in the period 2000–2005. On the other hand, we find that a moderate (less than 5% per decade) increase in the global OH concentration can bring the model in agreement with the measurements for plausible emission scenarios. This study demonstrates the value of global monitoring of methane isotopes, and calls for further investigation into the role OH and anthropogenic emissions to further improve our understanding of methane variations in recent years.
A method to improve the determination of wave perturbations close to the tropopause by using a digital filter
Authors: Alexander P. , de la Torre A. , Llamedo P. , Hierro R. , Schmidt T. , Haser A. , Wickert J.
Published: February 2011

Abstract. Calculations of gravity wave activity all over the globe derived from GPS radio occultation temperature profiles led some years ago to the following question: are the wave amplitude enhancements systematically observed around tropopause levels due to physical processes or are they a simple artifact generated by any digital filter used to isolate the wave components? The latter alternative has been found to be the correct one. This has been concluded after almost a decade of work on global wave climatologies obtained from GPS radio occultation satellite data, which allowed to analyze, for the first time, a large amount of atmospheric profiles including both the troposphere and the stratosphere. We present a new filtering method which can be equally applied to temperature or refractivity profiles. The suggested technique significantly reduces artificial enhancements around the tropopause, which represents an improvement in comparison to previous applications of standard filters.
Seasonal and interannual variability of physical and biological dynamics at the Shelfbreak Front of the Middle Atlantic Bight: nutrient supply mechanisms
Authors: He R. , Chen K. , Fennel K. , Gawarkiewicz G. G. ,   D. J. McGillicuddy Jr.
Published: February 2011

Abstract. A size-structured ecosystem model is coupled to a 3-dimensional, high-resolution circulation model to investigate the seasonal and interannual variability of physical and biological states and their driving mechanisms at the shelfbreak front of the Middle Atlantic Bight (MAB). Simulated surface chlorophyll fields compare favorably to the satellite observations and capture the shelfbreak biomass enhancement, which is one of the essential biological features of the region. The domain-wide upper water column nutrient content peaks in late winter-early spring. The phytoplankton spring bloom starts 1–2 months later, followed by a zooplankton bloom in early summer. Seasonal and interannual variability in hindcast shelfbreak nutrient supply is controlled by three processes: (1) local mixing that deepens the mixed layer and injects deep ocean nutrients into the upper water column; (2) alongshore nutrient transport by the shelfbreak jet and associated currents; and (3) nutrient upwelling associated with shelfbreak bottom boundary layer convergence. Interannual variability of physical and biological processes are highlighted by cross-shelf nutrient budget diagnostics for spring 2004 and 2007, which show not only complex vertical structure of various dynamical terms, but also significant variations in magnitude between the two years.
Entropy production and multiple equilibria: the case of the ice-albedo feedback
Authors: Herbert C. , Paillard D. , Dubrulle B.
Published: February 2011

Abstract. Nonlinear feedbacks in the Earth System provide mechanisms that can prove very useful in understanding complex dynamics with relatively simple concepts. For example, the temperature and the ice cover of the planet are linked in a positive feedback which gives birth to multiple equilibria for some values of the solar constant: fully ice-covered Earth, ice-free Earth and an intermediate unstable solution. In this study, we show an analogy between a classical dynamical system approach to this problem and a Maximum Entropy Production (MEP) principle view, and we suggest a glimpse on how to reconcile MEP with the time evolution of a variable. It enables us in particular to resolve the question of the stability of the entropy production maxima. We also compare the surface heat flux obtained with MEP and with the bulk-aerodynamic formula.
Evaluation of ice and snow content in the global numerical weather prediction model GME with CloudSat
Authors: Eikenberg S. , Fröhlich K. , Seifert A. , Crewell S. , Mech M.
Published: February 2011

Abstract. The present study evaluates the global numerical weather prediction model GME with respect to frozen particles, both ice and snow, focusing on the performance of a diagnostic versus a prognostic precipitation scheme. As a reference, CloudSat Cloud Profiling Radar observations are utilized – the so far only near-globally available data set which vertically resolves clouds. Both the observation-to-model and the model-to-observation approach are applied and compared to each other. For the latter, the radar simulator QuickBeam is utilized. Criteria are applied to further improve the comparability between model and observations. The two model versions are statistically evaluated for a four-month period. The comparison reveals that the prognostic scheme reproduces the shape of the CloudSat frequency distributions for both ice water content (IWC) and reflectivity factor well, while the diagnostic scheme produces no large IWCs or reflectivity factors because snow falls out instantaneously. However, the prognostic scheme overestimates the occurrence of high ice water paths (IWP), especially in the mid-latitudes. Sensitivity tests show that an increased fall speed of snow successfully reduces IWP. Both approaches capture the general features, but for details, the two together deliver the largest informational content. In case of limited resources, the model-to-observation approach is preferred. Finally, the results indicate that the lack of IWC in most global circulation models might be attributed to the use of diagnostic precipitation schemes, i.e., the lack of snow aloft. Based on its good performance the prognostic scheme went into operational mode in February 2010. The adjusted snow fall speed went operational in December 2010. However, continual improvements of the ice microphysics are necessary, which can be assessed by the proposed evaluation technique.
Geophysical characterisation of two segments of the Møre-Trøndelag Fault Complex, Mid-Norway
Authors: Nasuti A. , Pascal C. , Ebbing J. , Tønnesen J. F.
Published: February 2011

Abstract. The Møre-Trøndelag Fault Complex (MTFC) has controlled the tectonic evolution of Mid-Norway and its shelf for the past 400 Myr through repeated reactivations during Paleozoic, Mesozoic and perhaps Cenozoic times, the very last phase of reactivation involving normal to oblique slip faulting. Despite its pronounced signature in the landscape, its deep structure has remained unresolved until now. We focused on two specific segments of the MTFC (i.e. the so-called "Tjellefonna" and "Bæverdalen" faults) and acquired multiple geophysical data sets (i.e. gravity, magnetic, resistivity and shallow refraction profiles). A 100–200 m wide zone of gouge and/or brecciated bedrock dipping steeply to the south is interpreted as being the "Tjellefonna Fault" stricto sensu. The fault appears to be flanked by two additional but minor damage zones. A secondary normal fault also steeply dipping to the south but involving indurated breccias was detected ~1 km farther north. The "Bæverdalen Fault" is interpreted as a ~700 m wide and highly deformed zone involving fault gouge, breccias and lenses of intact bedrock, as such it is probably the most important fault segment in the studied area and accommodated most of the strain during presumably late Jurassic normal faulting. Our geophysical data are indicative of a "Bæverdalen Fault" dipping steeply towards the south, in agreement with the average orientation of the local tectonic grain. Our findings suggest that the influence of Mesozoic normal faulting along the MTFC on landscape development is more complex than previously anticipated.
Glacier changes on Sierra Velluda massif, Chile (37° S): mountain glaciers of an intensively-used mid-latitude landscape
Authors: Fernández A. , Santana A. , Jaque E. , Martínez C. , Sáez R.
Published: February 2011

Abstract. The central-southern section of Chile is defined as one of the Latin American hot spots in the last IPCC Report due to the impact of glacier retreat on water resources, the transitional character of the climate, and its importance in terms of agricultural and forestry activities. In order to provide a better understanding of glacier behavior in this zone, this paper analyzes the volumetric changes of glaciers in the Sierra Velluda, located in the upper Bío Bío River Basin. Bibliographic sources, satellite images, and DEMs were used to estimate frontal, areal, and volumetric changes. An analysis of significance was performed in order to provide accurate estimations of the fluctuations. The results indicate that Sierra Velluda glaciers have suffered a significant reduction since the 1960s, despite some short periods of positive fluctuations. A maximum position of a glacier for the year 1828 was identified, which is in concordance with other proxies registered elsewhere in Chile. These changes agree with measurements of glacier fluctuation elsewhere in Chile. While short-term fluctuations are consistent with the inter-annual precipitation variability, lake levels records, and a warm phase of the El Niño Southern Oscillation (ENSO), the general shrinkage agrees with the shift of the ENSO (PDO) in 1976. Therefore, it is proposed that Sierra Velluda's glaciers are highly sensitive to high frequency climatic fluctuations and even to inter-annual variability. Considering that models project a reduction in Andean precipitation and an altitudinal increase in the 0 °C isotherm, these ice bodies are expected to continue to shrink.
Concordance between Clinical and Histopathologic Diagnosis in Recipient Corneas
Authors: Kanavi Mozhgan Rezaei , Javadi Atefeh , Ali Javadi Mohammad , Yaseri Mehdi , Feizi Sepehr
Published: February 2011

Purpose.

To specify a concordance rate between the preoperative clinical and the postoperative histopathologic diagnosis in recipient corneas referred to the pathology department of Central Eye Bank of Iran.

Methods.

Concordance and discrepancy between the preoperative clinical and postoperative histopathologic diagnosis of recipient corneal buttons were evaluated.

Results.

Overall, 340 corneal specimens were evaluated. The total concordance rate between the clinical and histopathologic diagnoses was 97.5%. The concordance rate in keratoconus, nonspecific scar and opacity, mustard gas keratopathy, combined keratoconus and dystrophy, postkeratorefractive keratectasia, and chemical burns was 100%. Discordant cases were observed in acquired corneal endothelial decompensation, corneal dystrophies, infectious keratitis, and miscellaneous causes, with the rate of 6.0%, 4.1%, 2.8%, and 16.6%, respectively.

Conclusions.

Our series demonstrated a significantly high concordance between the preoperative clinical and the postoperative histopathologic diagnosis in recipient corneas with different types of corneal disorders.
Genetic screening for Krabbe disease: Learning from the past and looking to the future
Authors: Macarov Michal , Zlotogora Joel , Meiner Vardiella , Khatib Zinab , Sury Vivi , Mengistu Getu , Bargal Ruth , Shmueli Esther , Meidan Bela , Zeigler Marsha
Published: February 2011

In Israel, Krabbe disease is frequent in two Moslem Arab villages in the Jerusalem area. In this paper we present our experience of almost four decades with diagnosis of Krabbe disease, carrier screening and prenatal diagnosis. The screening program is well accepted by the community, and there is a clear trend towards premarital testing. The screening program and prenatal diagnosis have led to a decrease in the incidence of Krabbe disease from 1.6 per 1,000 live births to 0.82 per 1,000. © 2011 Wiley‐Liss, Inc.
Isolated skeletal malformations in a child with a small mosaic ring microduplication of 18 p11.21q11.2: Genotype–phenotype correlations
Authors: Slavin Thomas P. , Kuruvilla Kevin , Curtis Christine A. , Christ Laurie A. , Mitchell Anna L.
Published: February 2011

We describe a developmentally normal Amish child who has a karyotype with 47 chromosomes, including a supernumerary ring‐shaped chromosome 18 in each metaphase studied. The only phenotypic findings in the patient were hemivertebrae and rib anomalies. Further analysis of interphase cells revealed an additional, less frequent mosaic, apparently normal cell population. Genes in the triplicated region that possibly are contributing to her skeletal phenotype include GATA6, MC2R, MC5R, RBBP8, ESCO1, and ROCK1, among others. By studying such patients with abnormal genetic dosage, genotype–phenotype correlations can be used to refine gene function. © 2011 Wiley‐Liss, Inc.
Blepharophimosis mental retardation syndrome Say‐Barber/Biesecker/Young‐Simpson type – New findings with neuroimaging
Authors: Szakszon Katalin , Berényi Ervin , Jakab András , Bessenyei Beáta , Balogh Erzsébet , Köbling Tamás , Szilvássy Judit , Knegt Alida C. , Oláh Éva
Published: February 2011

We report on a female patient with blepharophimosis mental retardation syndrome of Say/Barber/Biesecker/Young‐Simpson (SBBYS) type. Main findings in her were marked developmental delay, blepharophimosis, ptosis, cleft palate, external auditory canal stenosis, small and malformed teeth, hypothyroidism, hearing impairment, and joint limitations. We performed diffusion tensor magnetic resonance imaging (MRI) and tractography of the brain which showed inappropriate myelination and disturbed white matter integrity. Cytogenetic analysis, subtelomeric fluorescence in situ hybridization and comparative genomic hybridization failed to identify an abnormality. It remains uncertain whether the MRI findings are specific to the present patient or form part of the SBBYS syndrome. © 2011 Wiley‐Liss, Inc.
Linking chromosome abnormality and copy number variation
Authors: Cody Jannine D. , Hale Daniel E.
Published: February 2011

Nine out of 10 people has a chromosome copy number variation (CNV) of >1,000 bp of DNA. In some cases they are inconsequential, in other cases the variations cause disease or disability, and in most cases the relevance has not been elucidated. Several studies describe CNVs as “normal” biological variants while other studies suggest that CNVs may be associated with developmental disability. A concerted effort is needed to classify genes according to their dosage sensitivity, or to their lack of sensitivity. Over time, this effort will lead to the establishment of principles that permit the prediction of the consequence of any one genomic copy number change. © 2011 Wiley‐Liss, Inc.
Clinical, pathological, and molecular analyses of cardiovascular abnormalities in Costello syndrome: A Ras/MAPK pathway syndrome
Authors: Lin Angela E. , Alexander Mark E. , Colan Steven D. , Kerr Bronwyn , Rauen Katherine A. , Noonan Jacqueline , Baffa Jeanne , Hopkins Elizabeth , Sol‐Church Katia , Limongelli Giuseppe , Digilio Maria Christina , Marino Bruno , Innes A. Micheil , Aoki Yoko , Silberbach Michael , Delrue Marie‐Ange , White Susan M. , Hamilton Robert M. , O'Connor William , Grossfeld Paul D. , Smoot Leslie B. , Padera Robert F. , Gripp Karen W.
Published: February 2011

Cardiovascular abnormalities are important features of Costello syndrome and other Ras/MAPK pathway syndromes (“RASopathies”). We conducted clinical, pathological and molecular analyses of 146 patients with anHRASmutation including 61 enrolled in an ongoing longitudinal study and 85 from the literature. In our study, the most common (84%)HRASmutation was p.G12S. A congenital heart defect (CHD) was present in 27 of 61 patients (44%), usually non‐progressive valvar pulmonary stenosis. Hypertrophic cardiomyopathy (HCM), typically subaortic septal hypertrophy, was noted in 37 (61%), and 5 also had a CHD (14% of those with HCM). HCM was chronic or progressive in 14 (37%), stabilized in 10 (27%), and resolved in 5 (15%) patients with HCM; follow‐up data was not available in 8 (22%). Atrial tachycardia occurred in 29 (48%). Valvar pulmonary stenosis rarely progressed and atrial septal defect was uncommon. Among those with HCM, the likelihood of progressing or remaining stable was similar (37%, 41% respectively). The observation of myocardial fiber disarray in 7 of 10 (70%) genotyped specimens with Costello syndrome is consistent with sarcomeric dysfunction. Multifocal atrial tachycardia may be distinctive for Costello syndrome. Potentially serious atrial tachycardia may present in the fetus, and may continue or worsen in about one‐fourth of those with arrhythmia, but is generally self‐limited in the remaining three‐fourths of patients. Physicians should be aware of the potential for rapid development of severe HCM in infants with Costello syndrome, and the need for cardiovascular surveillance into adulthood as the natural history continues to be delineated. © 2011 Wiley‐Liss, Inc.
Molecular cytogenetic and clinical characterization of a patient with a 5.6‐Mb deletion in 7p15 including HOXA cluster
Authors: Jun Kyung Ran , Seo Eul‐Ju , Lee Jin‐Ok , Yoo Han‐Wook , Park In‐Sook , Yoon Hye‐Kyung
Published: February 2011

Here, we describe the clinical features of a boy with a 5.6‐Mb deletion at chromosome 7p15.1–p15.3. He has mild facial anomalies, hand‐foot abnormalities, hypospadias, congenital heart defects, and supernumerary nipples. This deletion was detected by array comparative genomic hybridization and verified by fluorescence in situ hybridization using BACs selected from the USCS genome browser. This deletion was not found in subsequent FISH analysis of the parental chromosomes. The deleted region contains several genes, including contiguous developmental genes on the HOXA cluster, which play a role in regulating aspects of morphogenesis during normal embryonic development. The patient's limb and urogenital features were similar to those observed in hand‐foot‐genital syndrome, which is caused by haploinsufficiency of HOXA13, whereas the congenital heart defect may reflect the deletion of HOXA3. We hypothesized that many clinical features of the patient were due to combined haploinsufficiency of the HOXA cluster. Our study also demonstrates the clinical usefulness of a molecular cytogenetic tool that is capable of detecting imbalances in the genome. © 2011 Wiley‐Liss, Inc.
Effect of shape and orientation of carbon steel fiber on the modulus of epoxy‐based composite
Authors: Ghoraishi M. S. , Zadhoush A. , GharehAghaji A. A.
Published: February 2011

In this research work, the effect of parameters such as orientation, length, and shape of fibers were investigated. Flat and waved carbon steel fibers with 15 mm length were used with different orientations. The effect of orientation and shape of fibers on composite modulus was investigated. Fiber‐reinforced epoxy resin with 30 mm waved and endhooked fibers were also investigated. The theoretical results obtained using Halpin‐Tsai model are in good agreement with the experimental results for all the shapes and orientations. Because of the mechanical interlock, the shaped fibers can bridge matrix cracks effectively and improve composite's modulus. Improvement of modulus using shaped fibers for certain orientations has been achieved. The results obtained are useful in the application of texturising on the synthetic fibers in polymeric materials and provide flexibility in design of any demanded shape through improving modulus at different angles. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Functionality of wheat straw lignin extracted in organic acid media
Authors: Delmas Guo‐Hua , Benjelloun‐Mlayah Bouchra , Bigot Yves Le , Delmas Michel
Published: February 2011

Wheat straw lignin was extracted by the CIMV process using organic acid media at pilot plant scale. The product was analyzed by gel permeation chromatography (GPC), 1H and 13C NMR spectroscopy, infrared attenuated total reflectance‐Fourier transform infrared analysis (ATR‐FTIR), and gas chromatography (GC) to clarify its structure and functionality. In most cases, lignin was esterified before analysis. Control of the esterification was conducted via ATR‐FTIR and NMR. GC analysis was used to quantify total hydroxyl group of lignin by saponification of propionylated lignin and was also used to quantify phenolic hydroxyl groups of lignin by aminolysis of propionylated lignin. Acetylated lignin was analyzed by GPC. Carboxylic group of lignin was determined by pH metric titration. Lignin extracted from the CIMV process was observed as a low molecular weight polymer with a low polydispersity index and high free hydroxyl content. The potential of lignin as a natural polyphenol was confirmed by the analytical results obtained. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Mechanical and thermal characteristics and morphology of polyamide 6/isotactic polypropylene blends in the presence of a β‐nucleating agent
Authors: Li Jie , Wang Shi‐Wei , Yang Wei , Xie Bang‐Hu , Yang Ming‐Bo
Published: February 2011

The mechanical and thermal characteristics and morphology of polyamide 6 (PA6)/isotactic polypropylene (iPP) blends (10/90 w/w) prepared with different processing procedures and incorporated with an aryl amide nucleating agent, a kind of β‐nucleating agent (β‐NA) for iPP, were investigated. The yield strength and flexural modulus of the blends decreased as β‐NA was introduced into the blends, whereas the impact strength and elongation at break improved. The crystalline structures of the blends closely depended on (1) the processing conditions and (2) competition between the β‐nucleating effect of β‐NA and the α‐nucleating effect of PA6 for iPP. Scanning electron microscopy, differential scanning calorimetry, and X‐ray diffraction were adopted to reveal the microstructures of the blends. At a low β‐NA content (<0.1 wt %), the α‐phase iPP dominated the blends, whereas the relative content of the β‐phase iPP increased remarkably when the β‐NA content was not less than 0.1 wt %. The processing conditions also showed profound influences on the supermolecular structures of iPP; this resulted in different mechanical properties of the blends. As for PA6, the crystallization behavior and crystalline structure did not exhibit obvious changes, but PA6 did play an important role in the epitaxial crystallization of iPP on PA6. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Syntheses of an azo‐group‐bound silica initiator and silica–polystyrene composites
Authors: Feng Libang , Ye Jiaofeng , Qiang Xiaohu , Zhang Hongxia
Published: February 2011

In this article, we present a facile method for the synthesis of an azo‐group‐bound silica (SiO2–azo) initiator. The azo groups were introduced onto the surface of silica (SiO2) nanoparticles via facile condensation between 4,4′‐azobis‐4‐cyanopentanoic acid and the alkyl–hydroxyl groups ‐ immobilized on the SiO2 nanoparticle surface under ambient conditions. The polystyrene (PS) chains were grafted onto the SiO2 nanoparticle surface by in situ polymerization with the resulting SiO2–azo as an initiator, and then, the SiO2–PS composite was prepared. The syntheses and properties of the SiO2–azo initiator and the composite were characterized by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, thermogravimetric analysis, gel permeation chromatography, and differential scanning calorimetry techniques. The results confirm that the SiO2–azo initiator and the composite were synthesized successfully. Styrene was polymerized with the initiation of SiO2–azo, and the resulting PS domain accounted for 48.6% of the total amount of composite. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Improvement of the mechanical and electrical properties of waste rubber with carbon nanotubes
Authors: Mahmoud Waleed E. , El‐Mossalamy E. H. , Arafa H. M.
Published: February 2011

The effect of carbon nanotubes (CNTs) on the stability of the mechanical and electrical properties of recycled waste rubber was experimentally investigated. The stress–strain curves of the composites were studied. The results show that the toughness, the area under the stress–strain curve, of the recycled rubber increased monotonically as a result of the addition of CNTs. The modulus of the nanocomposites increased by 28 times when only 5 wt % CNTs was added to the recycled rubber matrix. The effects of the cyclic fatigue and hysteresis for the composites were also examined. The strain energy density, dissipation energy, and linear damage accumulation versus the number of cycles are discussed for all of the samples. The analysis of the results showed that the strain energy density increased by 15 times at a CNT concentration of 5 wt %. The electrical properties were measured for all of the samples. The results indicate that the addition of CNTs to the recycled rubber improved its electrical conductivity by more than two orders. © 2011 Wiley Periodicals, Inc. J Polym Sci, 2011
Cross‐linking of ethylene‐octene copolymer (EOC) by dicumyl peroxide (DCP)
Authors: Svoboda Petr , Poongavalappil Sameepa , Theravalappil Rajesh , Svobodova Dagmar , Mokrejs Pavel , Kolomaznik Karel , Ougizawa Toshiaki , Inoue Takashi
Published: February 2011

Ethylene‐octene copolymer (EOC) was crosslinked by dicumyl peroxide (DCP) at various temperatures (150–200°C). Six concentrations of DCP in range 0.2–0.7 wt % were investigated. cross‐linking was studied by rubber process analyzer (RPA) and by differential scanning calorimetry (DSC). From RPA data analysis real part modulus s', tan δ, and reaction rate were investigated as a function of peroxide content and temperature. The highest s'max and the lowest tan δ were found for 0.7% of DCP at 150°C. Chain scission was analyzed by slope analysis of conversion ratio, X in times after reaching the maximum. Less susceptible to chain scission are temperatures in range 150–170°C and peroxide levels 0.2–0.5%. Heat of reaction was analyzed by DSC at various heating rates (5–40°C min−1). It was found to be exothermic. By projection to zero heating rate, the reaction was found to start at 128°C with the maximum at 168°C. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Facile preparation of nylon 6 nanocomposites based on clay reinforcement and core‐shell latex toughening: Morphology, properties, and impact fracture behavior
Authors: Sun Shuangyue , He Yadong , Wang Xiaodong , Wu Dezhen
Published: February 2011

This work is focused on a facile route to prepare a new type of nylon 6‐based nanocomposites with both high fracture toughness and high strength. A series of nylon 6‐matrix blends were prepared via melting extrusion by compounding with poly (methyl methacrylate‐co‐butadiene‐co‐styrene) (MBS) or poly(methyl methacrylate‐co‐methylphenyl siloxane‐co‐styrene) (MSIS) latices as impact modifier and diglycidyl ether of bisphenol‐A (DGEBA) as compatibilizer. Layered organic clay was also incorporated into above nylon 6 blends for the reinforcement of materials. Morphology study suggests that the MBS or MSIS latex particles could achieve a mono‐dispersion in nylon 6 matrix with the aid of DGEBA, which improves the compatibilization and an interfacial adhesion between the matrix and the shell of MBS or MSIS. High impact toughness was also obtained but with a corresponding reduction in tensile strength and stiffness. A moderate amount of organic clay as reinforcing agent could gain a desirable balance between the strength, stiffness and toughness of the materials, and tensile strength and stiffness could achieve an improvement. This suggests that the combination of organic clay and core‐shell latex particles is a useful strategy to optimize and enhance the properties of nylon 6. Morphology observation indicates that the layered organic clay was completely exfoliated within nylon 6 matrix. It is found that the core‐shell latex particles and the clay platelets were dispersed individually in nylon 6 matrix, and no clay platelets were present in MBS or MSIS latex particles. So the presence of the clay in nylon 6 matrix does not disturb the latex particles to promote high fracture toughness via particle cavitation and subsequent matrix shear yielding, and therefore, provides maximum reinforcement to the polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Mechanical and thermal properties of biocomposites from poly(lactic acid) and DDGS
Authors: Li Yonghui , Susan Sun Xiuzhi
Published: February 2011

Distillers dried grains with solubles (DDGS), an ethanol industry coproduct, is used mainly as a low‐value feedstuff. Poly(lactic acid) (PLA) is a leading biodegradable polymer, but its applications are limited by its relatively high cost. In this study, low‐cost, high‐performance biodegradable composites were prepared through thermal compounding of DDGS and PLA with methylene diphenyl diisocyanate (MDI) as a coupling agent. Mechanical, morphological, and thermal properties of the composites were studied. The coupling mechanism of MDI in the PLA/DDGS system was confirmed via Fourier‐transform infrared spectra. The PLA/20% DDGS composite with 1% MDI showed tensile strength (77 MPa) similar to that of pure PLA, but its Young's modulus was 25% higher than that of pure PLA. With MDI, strong interfacial adhesion was established between the PLA matrix and DDGS particles, and the porosity of the composites decreased dramatically. Crystallinity of PLA in the composites was higher than that in pure PLA. Composites with MDI had higher storage moduli at room temperature than pure PLA. This novel application of DDGS for biocomposites has significantly higher economic value than its traditional use as a feedstuff. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Phase separation induced morphology evolution andcorresponding impact fracture behavior of iPP/PEOc blends
Authors: Pang Yongyan , Dong Xia , Zhao Ying , Han Charles C. , Wang Dujin
Published: February 2011

In this study, the influence of phase separation on impact toughness of isotactic polypropylene (iPP)/poly(ethylene‐co‐octene) (PEOc) blends was investigated. For the typical toughened polymeric system, three iPP/PEOc compositions (80/20, 70/30, and 60/40) were selected. When the polymeric blends were annealed at 200°C, the coarsening of phase domains was more prominent for the blend containing higher content of PEOc, and the scale of its morphological evolution was increased as well. The impact test showed that the impact strength variation trend as a function of annealing time was closely related to morphological evolution. It was believed that the sharpening of phase boundary and coarsening of phase domains were responsible for the depression of impact toughness, and the probable fracture mode alteration from shear banding to crazing and voiding. Structure evolution induced by phase separation showed an important effect on impact toughness, and it was also affected by the environmental conditions. Proper temperature was required to catch the tough‐brittle transition induced by phase separation. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Flame‐retardant finishing in cotton fabrics using zinc oxide co‐catalyst
Authors: Lam Y. L. , Kan C. W. , Yuen C. W. M.
Published: February 2011

In this article, N‐Methylol dimethylphosphonopropionamide (FR) in combination with a melamine resin (CL), phosphoric acid (PA) catalyst and zinc oxide (ZnO) or nano‐ZnO co‐catalyst were used (FR‐CL‐PA‐ZnO or nano‐ZnO system) to impart flame‐retardant property on cotton fabrics. FR‐CL or FR‐CL‐PA‐treated cotton specimen showed roughened and wrinkled fabric surface morphology, which was caused by the attack of the FR with slightly acidity. In addition, FTIR analysis showed some new characteristic peaks, carbonyl, CH2 rocking and CH3 asymmetric and CH2 symmetric stretching bands, in the chemical structure of treated cotton specimens. Apart from these, the flame ignited on the flame‐retardant‐treated fabrics (without subjected to any post‐wet treatment) extinguished right after the removal of ignition source. However, FR‐CL treated specimens were no longer flame‐resistant when the specimens subjected to neutralization and/or home laundering, while FR‐CL‐PA treated specimens showed opposite results. By using 0.2% and 0.4% of ZnO or nano‐ZnO as co‐catalyst, the flame spread rate of neutralized and/or laundered test specimens decreased, even the specimens were undergone 10 home laundering cycles. Moreover, flame‐retardant‐treated cotton specimens had low breaking load and tearing strength resulting from side effects of the crosslinking agent used, while addition of ZnO or nano‐ZnO co‐catalyst could compensates for the reduction. Furthermore, the free formaldehyde content was dropped when ZnO and nano‐ZnO co‐catalyst was added in the treatment. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Sustainable Production: Practices and Determinant Factors of Green Supply Chain Management of Chinese Companies
Authors: Liu Xianbing , Yang Jie , Qu Sixiao , Wang Leina , Shishime Tomohiro , Bao Cunkuan
Published: February 2011

This paper explores the green supply chain management (GSCM) of companies based in the Yangtze River Delta, China. The companies' overall GSCM practice level (LGSCM) is measured by using the data from 165 valid respondents in a questionnaire survey conducted during April and May 2009. The relationships between LGSCM and the classified determinant factors are analyzed. It is indicated that Chinese companies are still at a preliminary stage of GSCM practices. Their environmental management in cooperation with external members of the supply chain is very marginal. A company's LGSCM is significantly and positively associated with the external pressures from regulatory, domestic clients and business competitors. As an internal factor, a company's learning capacity greatly determines LGSCM. We also confirm that the internal factors function as intermediate variables of external pressures in influencing a company's GSCM. A company's environmental management capacities will be strongly enhanced by frequent internal training of employees to increase its involvement in GSCM practices. Copyright © 2011 John Wiley & Sons, Ltd and ERP Environment.
Efficient lookup table based camera pose estimation for augmented reality
Authors: Li Shiqi , Xu Chi
Published: February 2011

Until now, exising camera pose estimation methods for the widely used square marker‐based augmented reality (AR) are either highly sensitive to noise or much time consuming, and developers have to work hard to find the proper trade‐off between computational speed and quality in mobile AR applications where computational resources are limited. The major difficulty is that only the four corner points of the square AR marker are available, and no redundant point correspondences can be used for a stable estimation. To solve this problem, an efficient lookup table (LUT)‐based non‐iterative solution is presented in this paper that achieves high stability in the presence of noise better than the most robust and accurate iterative solutions in the field, with the same level of accuracy and a much lower computational complexity. Our central idea consists of extracting a key parameter β from the camera pose and creating a LUT for β by taking the symmetrical structure of the square marker into account, thereby exploiting additional information. Copyright © 2011 John Wiley & Sons, Ltd.
Combining path planners and motion graphs
Authors: van Basten B.J.H. , Egges A. , Geraerts R.
Published: February 2011

Natural locomotion of virtual characters is very important in games and simulations. The naturalness of the total motion strongly depends on both the path the character chooses and the animation of the walking character. Therefore, much work has been done on path planning and generating walking animations. However, the combination of both fields has received less attention. Combining path planning and motion synthesis introduces several problems. In this paper, we will identify two problems and propose possible solutions. The first problem is selecting an appropriate distance metric for locomotion synthesis. When concatenating clips of locomotion, a distance metric is required to detect good transition points. We have evaluated three common distance metrics both quantitatively (in terms of footskating, path deviation and online running time) and qualitatively (user study). Based on our observations, we propose a set of guidelines when using these metrics in a motion synthesizer. The second problem is the fact that there is no single point on the body that can follow the path generated by the path planner without causing unnatural animations. This raises the question how the character should follow the path. We will show that enforcing the pelvis to follow the path will lead to unnatural animations and that our proposed solution, which uses path abstractions, generates significantly better animations. Copyright © 2011 John Wiley & Sons, Ltd.
Coronary artery bifurcation interventions: The disconnect between randomized clinical trials and patient centered decision‐making
Authors: Moussa Issam D.
Published: February 2011

The current evidence‐base pertaining to PCI in coronary bifurcation lesions is not adequate to inform decision making in all patients, hence a gap still exists between the evidence‐base and patient‐centered decision‐making. Although meta‐analyses of the existing RCTs improve the statistical power of the data they do not remedy the problem of trial design. The reason for the gap between “evidence” and patient‐centered decision‐making is that the research methodology used in the RCTs does not simulate the questions asked in practice. The purpose of this review is to make the case for a counter perspective to the narrative that provisional stenting (PS) [stenting the main vessel (MV), with additional stenting of the side branch (SB) only in the case of an unsatisfactory result] is better than elective double stenting (EDS) of both branches in all patients. Namely, that neither approach should be the default strategy in all patients with bifurcation lesions and a decision as to which technique to use should be based on the patient's bifurcation anatomy. The majority of patients with bifurcation lesions will have anatomy that can be safely treated with PS; however, some patients have “at risk” bifurcation anatomy where PS may be associated with high risk of side branch occlusion. © 2011 Wiley‐Liss, Inc.
Fundamental solutions of homogeneous fully nonlinear elliptic equations
Authors: Armstrong Scott N. , Smart Charles K. , Sirakov Boyan
Published: February 2011

We prove the existence of two fundamental solutions Φ and
$\tilde \Phi$
of the PDE
\input amssym $$F(D^2\Phi) = 0 \quad {\rm in} \ {\Bbb{R}}^n \setminus \{ 0 \}$$

for any positively homogeneous, uniformly elliptic operator F. Corresponding to F are two unique scaling exponents α*, $\tilde\alpha^*$
> −1 that describe the homogeneity of Φ and $\tilde \Phi$. We give a sharp characterization of the isolated singularities and the behavior at infinity of a solution of the equation F(D2u) = 0, which is bounded on one side. A Liouville‐type result demonstrates that the two fundamental solutions are the unique nontrivial solutions of F(D2u) = 0 in \input amssym ${\Bbb{R}}^n \setminus \{ 0 \}$
that are bounded on one side in both a neighborhood of the origin as well as at infinity. Finally, we show that the sign of each scaling exponent is related to the recurrence or transience of a stochastic process for a two‐player differential game. © 2010 Wiley Periodicals, Inc.
Performance analysis of job dissemination techniques in Grid systems
Authors: Bruneo Dario , Longo Francesco , Scarpa Marco , Puliafito Antonio
Published: February 2011

In the last few years, remarkable efforts have been made to extend the Grid paradigm to commercial solutions. Business‐oriented grids call for effective Quality of Service strategies able to adapt to different user requirements and to address Service Level Agreements. Performance analysis and prediction with respect to different load conditions or management policies are required to define such strategies. However, the highly distributed nature of Grid systems and the presence of distinct administrative domains make it difficult to carry out performance estimations. In fact, several parameters are involved and the autonomy of each site could make it complex to set them in a proper way. In this paper, we present a non‐Markovian Stochastic Petri Net methodology that allows to conduct performance analysis of Grid systems focusing on aspects related to the Virtual Organization as a whole. In particular, different job allocation techniques can be evaluated with respect to both user and provider points‐of‐view. The influence of different information update policies on the accuracy of the allocation schemes can also be investigated, highlighting the costs/benefits in terms of job waiting time, service availability, and system utilization. The proposed methodology is designed to be as general as possible and it can be applied to analyze a gLite Grid infrastructure taken as case study. Copyright © 2011 John Wiley & Sons, Ltd.
Effects of Distortion of Metal–Oxygen Octahedra on Photocatalytic Water‐Splitting Performance of RuO2‐Loaded Niobium and Tantalum Phosphate Bronzes
Authors: Nishiyama Hiroshi , Kobayashi Hisayoshi , Inoue Yasunobu
Published: February 2011

Sodium, niobium, and tantalum phosphate bronzes Na4M8P4O32 (M=Nb, Ta) are employed as photocatalysts for water splitting to reveal the effects of the distortion of metal–oxygen octahedra on the photocatalytic performance. Addition of RuO2 as a co‐catalyst leads to high, stable activity in the stoichiometric production of H2 and O2 under UV irradiation. The combination of highly crystallized phosphates and a high dispersion of RuO2 particles result in high photocatalytic activity. The sodium niobium phosphate bronze Na2Nb8P4O32, consisting of a framework built up from slabs of corner‐sharing NbO6 octahedra connected through isolated PO4 tetrahedra, provide heavily distorted NbO6 octahedra with large internal dipole moments. The results support the existing view that the activity correlates with the magnitude of the dipole moment. The heavy distortion of NbO6 octahedra is shown to play a significant role in photocatalytic water splitting.
A slot‐based BS scheduling with maximum latency guarantee and capacity first in 802.16e networks
Authors: Hsieh I‐Ping , Chang Fu‐Min , Kao Shang‐Juh
Published: February 2011

The IEEE 802.16e standard specifies the QoS support at the MAC level for wireless broadband access network. To meet the QoS requirements, an efficient scheduling algorithm at base station (BS), which is not defined in the standard, is necessary for slots allocation. In this paper, a Slot‐based BS scheduling algorithm with Maximum Latency Guarantee and Capacity First (SMLG‐CF) is proposed. With SMLG‐CF, the connection request is satisfied with highest slot capacity first. Together with the use of dynamic sub‐frame adjustment, the overall system transmission can be efficiently improved. Through the finer slots calculation and accurate transmission time scheduling, the maximum latency guarantee can be better achieved for urgent requests. In the simulation, we compare the proposed mechanism with the deficit fair priority queue scheduling algorithm and the Highest Urgency First scheduling algorithm. The simulation results reveal that SMLG‐CF outperforms both algorithms from the aspect of maximum latency violation rate and average transmission rate. Copyright © 2011 John Wiley & Sons, Ltd.