bluuebunny/crossref_metadata_2025 huggingface dataset:
Influence of aerosols and thin cirrus clouds on the GOSAT-observed CO2: a case study over Tsukuba
Authors: Uchino O. , Kikuchi N. , Sakai T. , Morino I. , Yoshida Y. , Nagai T. , Shimizu A. , Shibata T. , Yamazaki A. , Uchiyama A. , Kikuchi N. , Oshchepkov S. , Bril A. , Yokota T.
Published: April 2012

Abstract. Lidar observations of vertical profiles of aerosols and thin cirrus clouds were made at Tsukuba (36.05° N, 140.12° E), Japan, to investigate the influence of aerosols and thin cirrus clouds on the column-averaged dry-air mole fraction of carbon dioxide (XCO2) retrieved from observation data of the Thermal And Near-infrared Sensor for carbon Observation Fourier Transform Spectrometer, measured in the Short-Wavelength InfraRed band (TANSO-FTS SWIR), onboard the Greenhouse gases Observing SATellite (GOSAT). The lidar system measured the backscattering ratio, depolarization ratio, and/or the wavelength exponent of atmospheric particles. The lidar observations and ground-based high-resolution FTS measurements at the Tsukuba Total Carbon Column Observing Network (Tsukuba TCCON) site were recorded simultaneously during passages of GOSAT over Tsukuba. GOSAT SWIR XCO2 data (Version 01.xx) released in August 2010 were compared with the lidar and Tsukuba TCCON data. High-altitude aerosols and thin cirrus clouds had a large impact on the GOSAT SWIR XCO2 results. By taking into account the observed aerosol/cirrus vertical profiles and using a more adequate solar irradiance database in the GOSAT SWIR retrieval, the difference between the GOSAT SWIR XCO2 data and the Tsukuba TCCON data was reduced. The 3-band retrieval approach where the aerosol and cirrus profiles were retrieved gave us the best results and the retrieved XCO2 data followed the seasonal cycle of ~8 ppm observed at Tsukuba TCCON site.
Carbon and hydrogen isotopic ratios of atmospheric methane in the upper troposphere over the Western Pacific
Authors: Umezawa T. , Machida T. , Ishijima K. , Matsueda H. , Sawa Y. , Patra P. K. , Aoki S. , Nakazawa T.
Published: April 2012

Abstract. We present the mixing ratio, δ13C and δD of atmospheric CH4 using commercial aircraft in the upper troposphere (UT) over the Western Pacific for the period December 2005–September 2010. The observed results were compared with those obtained using commercial container ships in the lower troposphere (LT) over the same region. In the Northern Hemisphere (NH), the UT CH4 mixing ratio shows high values in the boreal summer–autumn, when the LT CH4 mixing ratio reaches a seasonal minimum. From tagged tracer experiments made using an atmospheric chemistry transport model, we found that such high CH4 values are due to rapid transport of air masses influenced by CH4 sources in South Asia and East Asia. The observed isotopic ratio data suggest that CH4 sources in these areas have relatively low δ13C and δD signatures, implying biogenic sources. Latitudinal distributions of the annual average UT and LT CH4 mixing ratio intersect each other in the tropics; the mixing ratio value is lower in the UT than in the LT in the NH and the situation is reversed in the Southern Hemisphere (SH), due mainly to the NH air intrusion into the SH through the UT. Such intersection of the latitudinal distributions is observable in δD but not in δ13C, implying additional contribution of a reaction of CH4 with active chlorine in the marine boundary layer. δ13C and δD show low values in the NH and high values in the SH both in the UT and in the LT. We also observed an increase in the CH4 mixing ratio and decreases in δ13C and δD during 2007–2008 in the UT and LT over the Western Pacific, possibly due to enhanced biogenic emissions in the tropics and NH.
Diurnal variations of organic molecular tracers and stable carbon isotopic compositions in atmospheric aerosols over Mt. Tai in North China Plain: an influence of biomass burning
Authors: Fu P. Q. , Kawamura K. , Chen J. , Li J. , Sun Y. L. , Liu Y. , Tachibana E. , Aggarwal S. G. , Okuzawa K. , Tanimoto H. , Kanaya Y. , Wang Z. F.
Published: April 2012

Abstract. Organic tracer compounds of tropospheric aerosols, as well as organic carbon (OC), elemental carbon (EC), water-soluble organic carbon (WSOC), and stable carbon isotope ratios (δ13C) of total carbon (TC) have been investigated for aerosol samples collected during early and late periods of Mount Tai eXperiment 2006 (MTX2006) field campaign in North China Plain. Total solvent extracts were investigated by gas chromatography/mass spectrometry. More than 130 organic compounds were detected in the aerosol samples. They were grouped into twelve organic compound classes, including biomass burning tracers, biogenic primary sugars, biogenic secondary organic aerosol (SOA) tracers, and anthropogenic tracers such as phthalates, hopanes and polycyclic aromatic hydrocarbons (PAHs). In early June when the field burning activities of wheat straws in North China Plain were very active, the total identified organics (2090 ± 1170 ng m−3) were double those in late June (926 ± 574 ng m−3). All the compound classes were more abundant in early June than in late June, except phthalate esters, which were higher in late June. Levoglucosan (88–1210 ng m−3, 403 ng m−3) was found as the most abundant single compound in early June, while diisobutyl phthalate was the predominant species in late June. During the biomass-burning period in early June, the diurnal trends of most of the primary and secondary organic aerosol tracers were characterized by the concentration peaks observed at mid-night or in early morning, while in late June most of the organic species peaked in late afternoon. This suggests that smoke plumes from biomass burning can uplift the aerosol particulate matter to a certain altitude and then transported to and encountered the summit of Mt. Tai during nighttime. On the basis of the tracer-based method for the estimation of biomass-burning OC, fungal-spore OC and biogenic secondary organic carbon (SOC), we estimate that an average of 24% (up to 64%) of the OC in the Mt. Tai aerosols was due to biomass burning in early June, followed by the contribution of isoprene SOC (mean 4.3%). In contrast, isoprene SOC was the main contributor (6.6%) to OC, and only 3.0% of the OC was due to biomass burning in late June. In early June, δ13C of TC (−26.6‰ to −23.2‰, mean −25.0‰) were lower than those (−23.9‰ to −21.9‰, mean −22.9‰) in late June. In addition, a strong anti-correlation was found between levoglucosan and δ13C values. This study demonstrates that crop-residue burning activities can significantly enhance the organic aerosol loading and alter the organic molecular compositions and stable carbon isotopic compositions of aerosol particles in the troposphere over North China Plain.
Horizontal and vertical structure of the Eyjafjallajökull ash cloud over the UK: a comparison of airborne lidar observations and simulations
Authors: Grant A. L. M. , Dacre H. F. , Thomson D. J. , Marenco F.
Published: April 2012

Abstract. During April and May 2010 the ash cloud from the eruption of the Icelandic volcano Eyjafjallajökull caused widespread disruption to aviation over northern Europe. Because of the location and impact of the eruption a wealth of observations of the ash cloud were obtained and can be used to assess modelling of the long range transport of ash in the troposphere. The UK's BAe-146-301 Atmospheric Research Aircraft overflew the ash cloud on a number of days during May. The aircraft carries a downward looking lidar which detected the ash layer through the backscatter of the laser light. The ash concentrations are estimated from lidar extinction coefficients and in situ measurements of the ash particle size distributions. In this study these estimates of the ash concentrations are compared with simulations of the ash cloud made with NAME (Numerical Atmospheric-dispersion Modelling Environment), a general purpose atmospheric transport and dispersion model. The ash layers seen by the lidar were thin, with typical depths of 550–750 m. The vertical structure of the ash cloud simulated by NAME was generally consistent with the observed ash layers. The layers in the simulated ash clouds that could be identified with observed ash layers are about twice the depth of the observed layers. The structure of the simulated ash clouds were sensitive to the profile of ash emissions that was assumed. In terms of horizontal and vertical structure the best results were mainly obtained by assuming that the emission occurred at the top of the eruption plume, consistent with the observed structure of eruption plumes. However, when the height of the eruption plume was variable and the eruption was weak, then assuming that the emission of ash was uniform with height gave better guidance on the horizontal and vertical structure of the ash cloud. Comparison between the column masses in the simulated and observed ash layers suggests that about 3% of the total mass erupted by the volcano remained in the ash cloud over the United Kingdom. The problems with the interpretation of this estimate of the distal fine ash fraction are discussed.
Predicting photosynthesis and transpiration responses to ozone: decoupling modeled photosynthesis and stomatal conductance
Authors: Lombardozzi D. , Levis S. , Bonan G. , Sparks J. P.
Published: April 2012

Abstract. Plants exchange carbon dioxide and water, two key greenhouse gases, with the atmosphere through the processes of photosynthesis and transpiration, making them essential in climate regulation. Carbon dioxide and water exchange are typically coupled through the control of stomatal conductance, and the parameterization in many models often predict conductance based on photosynthesis values. Some environmental conditions, like exposure to high ozone (O3) concentrations, alter photosynthesis independent of stomatal conductance, so models cannot accurately predict both. The goals of this study were to test direct and indirect photosynthesis and stomatal conductance modifications based on O3 damage in a coupled Farquhar/Ball-Berry model. The same modifications were then tested in the Community Land Model (CLM) to determine the impacts on gross primary productivity (GPP) and transpiration. Modifying the Vcmax parameter and directly modifying stomatal conductance best predicts photosynthesis and stomatal conductance responses to chronic O3 over a range of environmental conditions. On a global scale, directly modifying conductance reduces the effect of O3 on both transpiration and GPP compared to indirectly modifying conductance, particularly in the tropics. The results of this study suggest that independently modifying stomatal conductance can improve the ability of models to predict hydrologic cycling, and therefore improve future climate predictions.
Lightning activity, rainfall and flash flooding – occasional or interrelated events? A case study in the island of Crete
Authors: Koutroulis A. G. , Grillakis M. G. , Tsanis I. K. , Kotroni V. , Lagouvardos K.
Published: April 2012

Abstract. The majority of cyclones passing over Crete in late autumn to early winter originate from southwest, west and northwest and are of varying size and intensity. A number of these cyclones cause flash floods. The present study reports the possible relationships between lighting activity and high precipitation related to flash flood events. In this study an attempt was made to correlate the lightning number and location, recorded by the ZEUS lightning detection system, with the rainfall characteristics for sixteen rain events (4 flood and 12 non-flood events) on the island of Crete, during the period 2008–2009. Spatiotemporal analysis of rain and rain rate with flash count was performed with respect to distance (radius) of flashes from raingauge location at various temporal scales, in order to examine the correlation of accumulated rainfall and lightning activity. The maximum attained statistical significant correlation was obtained within a circular area of an average radius of 15 km around the raingauge, and an average time lag of flash count prior precipitation accumulation of 15 min. The maximum correlation between the lightning and rainfall data is obtained for shorter time lags for the flood events (15 min) than the non-flood events (25 min), that could reflect the faster propagation of flood triggering storms due to high convective activity. Results show increased lightning activity occurring during flood triggering storms, by an average of four times higher. Furthermore, there is evidence that the number of flashes that occur during a precipitation event is related to precipitation depth when the latter is adequate to produce a flood event. Differences between flood and non-flood producing storms need to be further assessed by analyzing more independent parameters, including the synoptic conditions and dominant flash flood hydrological generating processes.
Assimilation of SLA along track observations in the Mediterranean with an oceanographic model forced by atmospheric pressure
Authors: Dobricic S. , Dufau C. , Oddo P. , Pinardi N. , Pujol I. , Rio M.-H.
Published: April 2012

Abstract. A large number of SLA observations at a high along track horizontal resolution are an important ingredient of the data assimilation in the Mediterranean Forecasting System (MFS). Recently new higher frequency SLA products have become available, and the atmospheric pressure forcing has been implemented in the numerical model used in the MFS data assimilation system. In a set of numerical experiments we show that in order to obtain the most accurate analyses the ocean model should include the atmospheric pressure forcing and the observations should contain the atmospheric pressure signal. When the model is not forced by the atmospheric pressure the high frequency filtering of SLA observations, however, improves the quality of the analyses. It is further shown that MFS analyses, produced by an assimilation system given by the numerical model and the high frequency SLA observations, have a correct power spectrum at high wave numbers and they filter efficiently the SLA assimilated observations which, on the other hand, are contaminated by high wavenumber noise.
Repeat optical satellite images reveal widespread and long term decrease in land-terminating glacier speeds
Authors: Heid T. , Kääb A.
Published: April 2012

Abstract. By matching of repeat optical satellite images it is now possible to investigate glacier dynamics within large regions of the world and also between regions to improve knowledge about glacier dynamics in space and time. In this study we investigate whether the negative glacier mass balance seen over large parts of the world has caused the glaciers to change their speeds. The studied regions are Pamir, Caucasus, Penny Ice Cap, Alaska Range and Patagonia. In addition we derive speed changes for Karakoram, a region assumed to have positive mass balance and that contains many surge-type glaciers. We find that the mapped glaciers in the five regions with negative mass balance have over the last decades decreased their velocity at an average rate per decade of: 43 % in the Pamir, 8 % in the Caucasus, 25 % on Penny Ice Cap, 11 % in the Alaska Range and 20 % in Patagonia. Glaciers in Karakoram have generally increased their speeds, but surging glaciers and glaciers with flow instabilities are most prominent in this area. Therefore the calculated average speed change is not representative for this area.
The Process of General Education Reform from a Faculty Perspective:
Authors: Hachtmann Frauke
Published: April 2012

The purpose of this study was to explain the process and implementation of an outcomes-based general education program at a public, doctoral/research-extensive institution from the perspective of faculty. The theory that emerged explains how different causal, intervening, and contextual conditions interact with and affect the phenomenon of general education reform.
The Impact of the University of Utah's LEAP Program on Student Performance
Authors: Bliss Carolyn , Webb Jeff , Andre Mark St.
Published: April 2012

This article reports the results of a quantitative matching study investigating the impact on first-year students of a two-semester learning community. Results indicate a statistically significant association between leap participation and academic performance measured by retention, gpa, and time to graduation. Participation was associated with improved performance only for women.
The Cathodic Breakdown Test to Assess Chromic Acid Anodized Aluminum Alloys Corrosion Protection Performance, in Correlation with Salt Spray (Fog) Testing
Authors: Ouaziz Ghita , Savadogo Oumarou
Published: April 2012

The corrosion protection performance of chromic acid anodized (CAA) coating, applied on aerospace aluminum sheets is determined by the Cathodic Breakdown Test (CBT). The results were compared to those obtained with the classical salt spray test using the standard ASTM B117. A clear experimental procedure was developed to describe this non-standardized test, leading to the conclusion that the CBT results correlate well with those of the salt spray tests. All the sealed samples, which fail in CBT test, also fail in salt spray. The CBT was not identified as a useful tool to differentiate different types of unsealed aluminum bare samples. The CBT failure criteria set was successfully used in the identification of sealed sample failures from salt spray tests. The sealing performance of the sample was correlated to the CBT test parameters. The CBT test lasted at least 2000 times less long than the salt spray test. Furthermore the utilization of a relevant experimental procedure of the CBT testing method is an interesting way to lower significantly the testing time of the evaluation of corrosion protection performance of sensitive coated aerospace materials in comparison to the salt spray method.
Histopathological Features of Dental Pulp in Teeth with Different Levels of Chronic Periodontitis Severity
Authors: Zuza Elizangela Partata , Carrareto Ana Luiza Vanzato , Lia Raphael Carlos Comelli , Pires Juliana Rico , Toledo Benedicto Egbert Corrêa de
Published: April 2012

Purpose. To evaluate the histopathological condition of the pulp in teeth with different levels of chronic periodontitis in humans. Methods. Twenty-five single-root nondecayed teeth were divided into three groups as follows: group 1, clinical attachment level (CAL) 3 to 4 mm and alveolar bone loss (BL) from 4 to 6 mm without reaching the tooth apex; group 2, CAL≥5 mm and BL>6 mm without reaching the tooth apex; group 3, CAL≥5 mm and BL>6 mm up to the tooth apex. Histological analyses were accomplished after laboratorial processing. Results. The mean of CAL was 3.2±0.7 mm in group 1, 7.6±2.0 mm in group 2, and 12.1±2.8 mm in group 3, while for BL it was 4.8±0.9 mm, 7.6±2.2 mm, and 11.9±2.1 mm, respectively. Histopathological data in the pulpal chambers were similar among the three groups showing normal aspects, and, the radicular pulps showed variable levels of reactive dentin, fibrosis, dystrophic mineralizations, atrophy, and mononuclear inflammatory infiltrate. Conclusions. Gradual progression of the chronic periodontitis led to changes in the histopathological aspects of the radicular pulp with progressive involvement.
Targeted Delivery of Nanomedicines
Authors: Kumar Khanna Vinod
Published: April 2012

The role of targeting of the diseased region by a drug is emphasized. The rationale for resorting to nanomaterials as drug carriers is explained. A clear understanding of the biological environment, its degradation in diseased condition, and the interaction of the drug with it in normal condition and during illness lie at the core of successful drug delivery. Passive and active drug targeting approaches are differentiated. Commonly used drug targets, targeting ligands, and nanoscale systems are elaborated. Mechanisms of internalization of nanomedicines and circumventing P-glycoprotein mediated resistance are outlined. The paper presents an overview of the current scenario of targeted transportation of nanomedicines to the affected organ and suggests future research directions.
Predicting Software Projects Cost Estimation Based on Mining Historical Data
Authors: Najadat Hassan , Alsmadi Izzat , Shboul Yazan
Published: April 2012

In this research, a hybrid cost estimation model is proposed to produce a realistic prediction model that takes into consideration software project, product, process, and environmental elements. A cost estimation dataset is built from a large number of open source projects. Those projects are divided into three domains: communication, finance, and game projects. Several data mining techniques are used to classify software projects in terms of their development complexity. Data mining techniques are also used to study association between different software attributes and their relation to cost estimation. Results showed that finance metrics are usually the most complex in terms of code size and some other complexity metrics. Results showed also that games applications have higher values of the SLOCmath, coupling, cyclomatic complexity, and MCDC metrics. Information gain is used in order to evaluate the ability of object-oriented metrics to predict software complexity. MCDC metric is shown to be the first metric in deciding a software project complexity. A software project effort equation is created based on clustering and based on all software projects’ attributes. According to the software metrics weights values developed in this project, we can notice that MCDC, LOC, and cyclomatic complexity of the traditional metrics are still the dominant metrics that affect our classification process, while number of children and depth of inheritance are the dominant from the object-oriented metrics as a second level.
Nuevas políticas de seguridad vial y motivación de los ciudadanos
Authors: Tena-Sanchez Jordi , León Medina Francisco José
Published: April 2012

La evidencia empírica señala que las nuevas políticas de tráfi co aplicadasdesde 2004 han tenido una fuerte incidencia positiva sobre la conductade los conductores que se ha traducido en importantes descensos de lasiniestralidad. No obstante, no se ha prestado atención a cuáles han sidolos mecanismos sociales que dan cuenta de ese cambio ni a cuál ha sidoel impacto en la motivación de los ciudadanos. ¿Han tenido dichas políticasefectos «pedagógicos»? En el presente trabajo se analizan los datosdisponibles que permiten responder a esta pregunta. Dichos datos nopermiten afi rmar que las reformas hayan tenido ningún tipo de impactopositivo sobre la motivación de los conductores y la mejora del cumplimientoparece deberse al efecto disuasorio de las sanciones.
Gerontological Content in Canadian Nursing and Social Work Programs
Authors: Hirst Sandra P. , Lane Annette M. , Stares Brittany
Published: April 2012

MethodA survey of gerontological content in nursing and social work programs across Canada (English speaking) was conducted. The survey tool was the competencies list developed for interprofessional gerontological education by the National Initiative for the Care of the Elderly (NICE). Deans or designates of English-speaking nursing and social work programs across Canada were contacted by e-mail. Data was collected by Zoomerang.com.ResultsFindings indicate that clear progress is being made in ensuring that students have the knowledge and skills needed to provide the care required by older adults in a variety of settings.
Happy 2012!
Authors: Madden Ken
Published: April 2012

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Heterojunction Engineering of CdTe and CdSe Quantum Dots on TiO2 Nanotube Arrays: Intricate Effects of Size‐Dependency and Interfacial Contact on Photoconversion Efficiencies
Authors: Yang Haihua , Fan Wenguang , Vaneski Aleksandar , Susha Andrei S. , Teoh Wey Yang , Rogach Andrey L.
Published: April 2012

The quality of heterojunctions at the quantum dot (QD)‐TiO2 nanotube (TNT) interface has important implications on the efficiencies of photoelectrochemical solar cells. Here, it is shown that electrophoretic deposition of pre‐synthesized thioacid‐capped CdTe QDs results in relatively poor charge transfer across the heterojunctions. This is likely due to the intermediate layer of bifunctional linkers (S‐R‐COOH) in between the QDs and TNT. On the other hand, CdTe QD‐sensitized TNT prepared by in situ deposition in aqueous medium provides direct QD‐TNT contact, and hence more favorable heterojunction for charge transfer. This is exemplified not only by the drastic improvement in photocurrent efficiencies, but also provides clear difference on the size‐dependent electron injection efficiencies from the CdTe QDs of different sizes. By extending the system further to CdSe QDs, drastic enhancement is found when carrying out the in situ deposition in an organic medium. The results are discussed in terms of the nature of deposition and the corresponding charge transport characteristics. More importantly, the work reflects the intricacy of the effects of QD size and the quality of the heterojunctions on the overall photoconversion efficiencies.
Synaptic Learning and Memory Functions Achieved Using Oxygen Ion Migration/Diffusion in an Amorphous InGaZnO Memristor
Authors: Wang Zhong Qiang , Xu Hai Yang , Li Xing Hua , Yu Hao , Liu Yi Chun , Zhu Xiao Juan
Published: April 2012

A single synaptic device with inherent learning and memory functions is demonstrated based on an amorphous InGaZnO (α‐IGZO) memristor; several essential synaptic functions are simultaneously achieved in such a single device, including nonlinear transmission characteristics, spike‐rate‐dependent and spike‐timing‐dependent plasticity, long‐term/short‐term plasticity (LSP and STP) and “learning‐experience” behavior. These characteristics bear striking resemblances to certain learning and memory functions of biological systems. Especially, a “learning‐experience” function is obtained for the first time, which is thought to be related to the metastable local structures in α‐IGZO. These functions are interrelated: frequent stimulation can cause an enhancement of LTP, both spike‐rate‐dependent and spike‐timing‐dependent plasticity is the same on this point; and, the STP‐to‐LTP transition can occur through repeated “stimulation” training. The physical mechanism of device operation, which does not strictly follow the memristor model, is attributed to oxygen ion migration/diffusion. A correlation between short‐term memory and ion diffusion is established by studying the temperature dependence of the relaxation processes of STP and ion diffusion. The realization of important synaptic functions and the establishment of a dynamic model would promote more accurate modeling of the synapse for artificial neural network.
Carbon fibers based on pyrolytic lignin
Authors: Qin W. , Kadla J. F.
Published: April 2012

Carbon fibers were prepared from pyrolytic lignin isolated from a commercial bio‐oil by thermal spinning followed by carbonization. Compared to other technical lignins, a lower spinning temperature was required for the pyrolytic lignin. The pyrolytic lignins tended to develop fibers with hollow structures and were observed to fuse together during thermostabilization. However, a thermal treatment before fiber spinning was found to maintain the fiber integrity during thermostabilization and the following carbonization process. The mechanical properties and yield of the pyrolytic‐lignin‐based carbon fiber was found to be comparable to those based on other technical lignins. This work serves as a proof‐of‐concept study indicating pyrolytic lignin as a potential feedstock for low‐cost carbon‐fiber production. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Controlled release of prednisolone acetate from molecularly imprinted hydrogel contact lenses
Authors: Malaekeh‐Nikouei Bizhan , Ghaeni Fatemeh Abbasi , Motamedshariaty Vahideh Sadat , Mohajeri Seyed Ahmad
Published: April 2012

The aim of this work was to study the influence of methacrylic acid (MAA) as a comonomer and the application of a molecular imprinting technique on the loading and release properties of weakly crosslinked 2‐hydroxyethyl methacrylate (HEMA) hydrogels, with a view toward their use as reloadable soft contact lenses for the administration of prednisolone acetate (PA). The hydrogels were prepared with HEMA (95.90–98.30 mol %) as a backbone monomer, ethylene glycol dimethacrylate (140 mM) as a crosslinker, and MAA (0, 50, 100, or 200 mM) as a functional monomer. Different PA/MAA molar ratios (0, 1 : 8, 1 : 6, and 1 : 4) in the feed composition of the hydrogels were also applied to study the influence of the molecular imprinting technique on their binding properties. The hydrogels (0.4 mm thick) were synthesized by thermal polymerization at 60°C for 24 h in a polypropylene mold. The hydrogels were then characterized by the determination of their swelling and binding properties in water. Their loading and release properties were also studied in 0.9% NaCl and artificial lachrymal fluid. Increasing the MAA content of the hydrogel and applying the molecular imprinting technique led to an increase in the loading capacity of the hydrogel. The optimized imprinted hydrogel showed the highest affinity for PA and the greatest ability to control the release process, sustaining it for 48 h. The results obtained clearly indicate that the incorporation of MAA as a comonomer increased the PA loading capacity of hydrogel. Our data showed that the molecular imprinting technique also had a significant effect on the loading and release properties of the hydrogels. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Pore structure and liquid behavior of nonwovens composed of nanosized fibers by conjugate spinning
Authors: Li Yue , Joo Chang Whan
Published: April 2012

Nonwovens composed of nanofibers are of interest for use in high‐function textile materials, such as filtration, insulation, and absorption media. The pore structure of nonwovens has a dominant influence on the performance characteristics of the final products, particularly in controlling the transport properties. The transport properties include the filtration of gas and liquid, sound absorption, and heat transfer. In this study, we focused on the pore structure and liquid behavior of needle‐punched nonwovens composed of nanofibers produced by conjugate spinning. Nanofiber nonwovens were prepared with poly(ethylene terephthalate)/co‐(polyethylene terephthalate) sea‐island bicomponent fibers by an alkali treatment. The pore diameter distributions were experimentally obtained with a capillary flow porosimeter; this indicated that the nonwovens composed of nanofibers had a compact and uniform textile structure. Moreover, a comparison of the pore diameters, water absorption, and wicking behaviors of the nonwovens before and after the alkali treatment was made. The nonwovens composed of nanofibers possessed excellent water absorption capacities and fast wicking behaviors. Thus, they have promising potential applications as absorption media. In addition, a theoretical model of air volume and channel radius for liquid behavior was established and compared with the experimental results. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Polyurethane dispersions derived from polycarbonatediols by a solvent‐free process
Authors: Lee Da‐Kong , Tsai Hong‐Bing , Yang Zong‐Da , Tsai Ruey‐Shi
Published: April 2012

Aqueous polyurethane dispersions derived from various polycarbonatediols, carboxylic diols, and m‐di(2‐isocyantopropyl)benzene (TMXDI) were prepared by a solvent‐free process. The dispersing procedure was investigated by Fourier transform infrared spectroscopy and it was found that the use of TMXDI could avoid the over hydrolysis of the isocyanate groups during dispersing in water. The molecular weight tends to reach a maximum around an NH2/NCO ratio during chain extension of 0.8 : 1.0. The particle size, tensile properties, thermal properties, and dynamic mechanical properties of the polyurethane dispersions were investigated. The properties were significantly influenced by the molecular weight of the polycarbonatediols and the chemical structure of the carboxylic diols, and described by the effects of the ionic content, miscibility between the polycarbonate soft segment and the polyurethane segment, and the soft segment content. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Characterization of epoxy hybrid composites filled with cellulose fibers and nano‐SiC
Authors: Alamri H. , Low I. M.
Published: April 2012

Three different approaches have been applied and investigated to enhance the thermal and mechanical properties of epoxy resin. Epoxy system reinforced with either recycled cellulose fibers (RCF) or nanosilicon carbide (n‐SiC) particles as well as with both RCF and n‐SiC has been fabricated and investigated. The effect of RCF/n‐SiC dispersion on the mechanical and thermal properties of these composites has been characterized. The fracture surface morphology and toughness mechanisms were investigated by scanning electron microscopy. The dispersion of n‐SiC particles into epoxy nanocomposites was studied by synchrotron radiation diffraction and transmission electron microscopy. Results indicated that mechanical properties increased as a result of the addition of n‐SiC. The presence of RCF layers significantly increased the mechanical properties of RCF/epoxy composites when compared with neat epoxy and its nanocomposites. The influence of the addition of n‐SiC to RCF/epoxy composites in mechanical properties was found to be positive in toughness properties. At high temperatures, thermal stability of neat epoxy increased due to the presence of either n‐SiC particles or RCF layers. However, the presence of RCF accelerated the thermal degradation of neat epoxy as well as the addition of n‐SiC to RCF/epoxy samples increased the rate of the major thermal degradation. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Bulk polytransesterification of L‐lactic acid esters: An alternative route to synthesize poly(lactic acid)
Authors: Marques Dina S. , Gil M. H. , Baptista Cristina M. S. G.
Published: April 2012

The synthesis of poly(lactic acid) (PLA) by bulk polytransesterification of different L‐lactic acid esters was successfully carried out. The experiments were performed in two steps: a first one at 170°C, maximum temperature, and atmospheric pressure, to obtain a viscous oligomer; and a final step at 180°C and under reduced pressure to improve the byproduct elimination and increase the polymerization degree. The ethyl L‐lactate polytransesterification in the presence of the binary catalytic system Sb2O/Zn(O2CCH3)2·2H2O allowed achieving the highest average molecular weight, 22,300 g mol−1. The yellowing of the melt polymer samples was recorded. The resulting materials were subjected to several characterization techniques: the chemical structure of PLA was confirmed by 1H‐NMR, the molecular weight was determined by size exclusion chromatography, thermal behavior measured by differential scanning calorimetry and racemization extent by specific rotation measurements. A special attention was paid to the polymer optical purity, as it is of major importance to assess its quality and the significance of the synthesis route. To the best of our knowledge, there is no previous report dealing with the synthesis of PLA by bulk polytransesterification. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Isobaric relaxation phenomenon of mixed PMMA/PS‐b‐PEO monolayers at different temperatures
Authors: Jheng Kai‐Teng , Hsu Wen‐Ping
Published: April 2012

The objective of this research was to find out the effect of molecular weight of poly(methyl methacrylate) (PMMA) and temperature on the isobaric relaxation behaviors of mixed PMMA/poly(styrene)‐block‐poly(ethylene oxide) (PS‐b‐PEO) monolayers. Isobaric relaxation experiments of mixed monolayers of PMMA with different molecular weights and PS‐b‐PEO at the air/water interface were investigated at three different temperatures (10, 25, and 40°C). The PS‐b‐PEO monolayer was found to exhibit a fast relaxation curve (i.e., the surface area decreased significantly with increasing time). Addition of PMMA into PS‐b‐PEO slowed the relaxation behavior especially at the lowest experimental temperature (10°C). It was shown that the area relaxation process of mixed PMMA/PS‐b‐PEO monolayers could be well represented by a model considering the nucleation and growth mechanisms. The characteristic exponent x values were found to be almost temperature independent. The kx values were detected to decrease mostly as a result of temperature elevation regardless of pure or mixed monolayers. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Multifunctional ZnO‐biopolymer nanocomposite coatings for health‐care polymer foams and fabrics
Authors: Sanoop P. K. , Mahesh K. V. , Nampoothiri K. M. , Mangalaraja R. V. , Ananthakumar S.
Published: April 2012

Biopolymer‐mediated sonochemical synthesis has been carried out for obtaining stable, nanocrystalline ZnO‐biopolymer nanocomposite colloids to be applied on polymer foam and cotton fabrics to ultimately produce multifunctional, heath‐care surface modifications.In situnucleation and growth of nano‐ZnO was achieved by ultrasonication at ∼ 60°C in aqueous biopolymer media prepared using starch, gelatin, chitosan, and agar. Phase analysis, structure–bonding characteristics, ZnO morphology, particle size distributions, rheology, and thermal decompositions were studied using XRD, FTIR, SEM/TEM, viscometer, and TG/DTA tools. Morphologically varied nanocrystalline ZnO of size ∼ 40 nm were synthesized. Biopolymers media resulted in stable ZnO colloids through steric stabilization. ZnO‐biopolymer nanocomposites colloid was applied on polyurethane foams and cotton fabric substrates by dip coating. These coatings were examined for the UV photoactivity and resistance to fungi growth. A comparison has been made among the biopolymers. It is shown that the surface coatings of ZnO‐biopolymer nanocomposites can produce anti‐fungal, UV active polymer foams and fabrics. The study has significant relevance in automobile and hospital industries because such functionally modified polymer foams and cotton fabrics can be disinfected and refreshed just by periodic application of water‐free, UV cleaning. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Carbon nanotube/polypropylene composite particles for microwave welding
Authors: Wu Tongfei , Pan Yongzheng , Liu Erjia , Li Lin
Published: April 2012

Multiwalled carbon nanotube (MWCNT)/polypropylene (PP) composite particles with various compositions were prepared by mechanical grinding of PP microparticles and MWCNT powders in a mortar at room temperature. Scanning electron microscopy (SEM) revealed that PP particles were coated by MWCNTs, forming a core‐shell structure. The electrical resistivity versus temperature behavior of MWCNT/PP composite particles and the changes in phase structures before and after melting were studied. Furthermore, MWCNT/PP composite particles with 4 wt % MWCNT were used to weld PP substrates under microwave irradiation. The effects of the irradiation duration and the compression pressure on the welding strength were examined. Here, we have demonstrated a simple and economic method for polymer welding. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Investigation of the molecular weight of polyethylene using rheological techniques
Authors: Li Pengpeng , Yang Shiyuan , Wang Meiling
Published: April 2012

The zero shear viscosity (η0), relaxation time, relaxation spectrum index (RSI) of 20 metallocene‐catalyzed, and conventional polyethylenes are presented. The effect of molecular weight (Mw) determined by gel‐permeation chromatography on rheology parameters was analyzed. The dependence of zero shear viscosity or relaxation time on molecular weight allowed the polyethylene samples to be separated into three different groups and different values of parameter in
${\eta _{\rm{0}}} = K{{\rm{(}}{M_w})^\alpha }$
were obtained, respectively. Two groups of polymers display viscosity deviation from linear relationship and the reason was attributed to different level of long‐chain branching and high‐molecular weight tails. The intrinsic reason was disclosed when relaxation spectra at frequencies between 1 s and 10 s were involved and RSI was used for quantitative analysis. Thus, an alternative single rheological method, based on the effect of molecular structure on dynamic rheological behaviors, was proposed to evaluate the molecular weight of polyethylene. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
pH‐responsive release behavior of genipin‐crosslinked chitosan/poly(ethylene glycol) hydrogels
Authors: Liu Yangshuo , Chen Wenbao , Kim Hyung‐Il
Published: April 2012

Chitosan/poly(ethylene glycol) blends were crosslinked by the nontoxic genipin as a crosslinker to produce the pH‐responsive hydrogels. The pH‐responsive swelling and releasing behavior of chitosan/poly(ethylene glycol) hydrogels was studied by varying the contents of poly(ethylene glycol) (PEG) and genipin, and the molecular weights of PEG. The drug release increased as the pH of the medium decreased, because the protonation of amino acids in chitosan chains at the acidic condition caused the higher swelling of hydrogels. The drug release increased as the content of PEG increased, because the larger pores were formed in the hydrogel and the higher swelling of matrix was obtained. The drug release decreased with the increase of the content of genipin, because the higher degree of crosslinking impeded the diffusion of drug from the hydrogel matrix. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Synovial fluid from patients with early osteoarthritis modulates fibroblast‐like synoviocyte responses to Toll‐like receptor 4 and Toll‐like receptor 2 ligands via soluble CD14
Authors: Nair Anjali , Kanda Veero , Bush‐Joseph Charles , Verma Nikhil , Chubinskaya Susan , Mikecz Katalin , Glant Tibor T. , Malfait Anne‐Marie , Crow Mary K. , Spear Greg T. , Finnegan Alison , Scanzello Carla R.
Published: April 2012

Objective

Synovial inflammation, a feature of both osteoarthritis (OA) and meniscal injury, is hypothesized to be triggered in part via stimulation of Toll‐like receptors (TLRs). We undertook this study to test whether a TLR‐2– or TLR‐4–stimulating factor in synovial fluid (SF) from patients with early knee OA with meniscal injury could lead to inflammatory activation of synoviocytes.

Methods

SF was obtained from patients with early OA cartilage damage undergoing arthroscopic meniscal procedures. SF was used to stimulate primary cultures of fibroblast‐like synoviocytes (FLS) and cell lines transfected with TLR‐2 or TLR‐4. SF was used either alone or in combination with a TLR‐2 stimulus (palmitoyl‐3‐cysteine‐serine‐lysine‐4 [Pam3CSK4]) or a TLR‐4 stimulus (lipopolysaccharide [LPS]). In blocking experiments, SF was preincubated with anti‐CD14 antibody.

Results

SF from these patients did not stimulate interleukin‐8 (IL‐8) release from TLR transfectants. Compared with SF on its own, SF (at concentrations of 0.09–25%) in combination with TLR‐2 or TLR‐4 ligands resulted in significant augmentation of IL‐8 release from both transfectants and primary FLS. Soluble CD14 (sCD14), a coreceptor for TLRs, was measured in SF from patients with early OA at levels comparable to those in patients with advanced OA and patients with rheumatoid arthritis. Blockade with anti‐CD14 antibody abolished the ability of SF to augment IL‐8 production in response to LPS, and diminished Pam3CSK4 responses.

Conclusion

SF augments FLS responses to TLR‐2 and TLR‐4 ligands. This effect was largely due to sCD14. Our results demonstrate that sCD14 in the setting of OA and meniscal injury sensitizes FLS to respond to inflammatory stimuli such as TLR ligands.
Chinese consumer ethnocentrism: A field experiment
Authors: Bi Xiaogang , Gunessee Sailesh , Hoffmann Robert , Hui Wendy , Larner Jeremy , Ma Qing‐Ping , Thompson Frauke Mattison
Published: April 2012

Consumer ethnocentrism presents barriers for internationalising organisations. In China, evidence of a resurgent nationalism partly fuelled by rapid economic growth portends a shift in consumption away from foreign towards domestic products. On the other hand, rising consumer demand for branded and luxury products cannot be fully met domestically. However, much of the available evidence on Chinese consumer ethnocentrism is anecdotal and is based on attitudinal surveys that, as accurate measures of actual purchasing behaviour, suffer from certain methodological issues. In response, we report an experiment that measures the ethnocentrism of 447 Chinese consumers as their incentive‐compatible choices between foreign and domestic products in a field setting. Our findings show little effect of foreign origin on subjects' choices that were only weakly related with attitudinal measures including the commonly used consumer ethnocentric tendencies scale (CETSCALE). Our results question the existence of ethnocentric consumer behaviour in China and the use of CETSCALE to gauge it generally. Copyright © 2012 John Wiley & Sons, Ltd.
Support vector machine classification of suspect powders using laser‐induced breakdown spectroscopy (LIBS) spectral data
Authors: Cisewski Jessi , Snyder Emily , Hannig Jan , Oudejans Lukas
Published: April 2012

Classification of suspect powders, by using laser‐induced breakdown spectroscopy (LIBS) spectra, to determine if they could contain Bacillus anthracis spores is difficult because of the variability in their composition and the variability typically associated with LIBS analysis. A method that builds a support vector machine classification model for such spectra relying on the known elemental composition of the Bacillus spores was developed. A wavelet transformation was incorporated in this method to allow for possible thresholding or standardization, then a linear model technique using the known elemental structure of the spores was incorporated for dimension reduction, and a support vector machine approach was employed for the final classification of the substance. The method was applied to real data produced from an LIBS device. Several methods used to test the predictive performance of the classification model revealed promising results. Published 2012. This article is a US Government work and is in the public domain in the USA.
ent‐Kaurane Diterpenoids from Isodon eriocalyx var. laxiflora
Authors: Wang Weiguang , Wu Haiyan , Du Xue , Yan Juming , Li Yan , Pu Jianxin , Sun Handong
Published: April 2012

Four new ent‐kaurane diterpenoids, 6β,13α,15β‐trihydroxy‐16‐ene‐3α,20‐epoxy‐ent‐kaur‐1,7‐dione (1), 6‐hydroxy‐3α,20‐epoxy‐5(6)‐ene‐ent‐kaur‐1,7,15‐trione (2), 6‐hydroxy‐15β‐acetoxy‐3α,20‐epoxy‐16β,17‐epoxy‐5(6)‐ene‐ent‐kaur‐1,7‐dione (3), 3α,17‐dihydroxy‐15(16)‐ene‐ent‐kaur‐7‐one (4), along with four known compounds 5–8 were isolated from the leaves of Isodon eriocalyx var. laxiflora. The structures were elucidated by extensive spectroscopic methods (IR, UV, MS and NMR). The cytotoxic activities of these compounds were evaluated by MTT assay. Compound 8 showed moderate inhibitory effects on HL‐60, SMMC‐7721, MCF‐7 and SW‐480 cell lines.
Rapid Determination of Costunolide and Dehydrocostuslactone in Human Plasma Sample and Chinese Patent Medicine Xiang Sha Yang Wei Capsule Using HPLC‐DAD Coupled with Second‐order Calibration
Authors: Liu Yajuan , Wu Hailong , Zhu Shaohua , Kang Chao , Xu Hui , Su Zhiyi , Gu Huiwen , Yu Ruqin
Published: April 2012

A novel methodology that combines high performance liquid chromatography with photodiode‐array detector (HPLC‐DAD) coupled with second‐order calibration method based on alternating trilinear decomposition (ATLD) algorithm was used in determination of the effective constituents such as costunolide and dehydrocostuslactone, in plasma sample and Chinese patent medicine Xiang Sha Yang Wei (XSYW) capsule. Complicated systems such as plasma and Chinese patent medicine which have intricate components are tedious to isolate and purify. The problem that chromatographic peaks are heavily overlapped among the analytes and interferents from the background matrices can be resolved, and the satisfactory quantification results have been gained with the help of the ATLD algorithm which utilized "mathematical separation" instead of partial "physical or chemical separation". Meanwhile, HPLC‐MS/MS method was used to validate the accuracy of the proposed determination method.