bluuebunny/crossref_metadata_2025 huggingface dataset:
Letramento acadêmico e a construção de sentido nas leituras de um gênero
Authors: Fischer Adriana , Pelandré Nilcéa Lemos
Published: July 2011

O objetivo deste trabalho é caracterizar como as diferentes formas de leitura situada de um gênero contribuem para que alunos se assumam insiders em contexto acadêmico. Os dados em análise foram coletados em 2005 e 2006, em um curso brasileiro de licenciatura, através de observações participantes e de entrevistas orais. Esses dados constituem parte dos eventos nomeados reflexivo-transformativos, incluindo leitura, produção e análise linguística do gênero discursivo crônica jornalística. Esses eventos também integram o modelo dialógico dos letramentos acadêmicos, que se reporta à construção de sentidos, à identidade, ao  poder, à autoridade e à natureza institucional do que conta como conhecimento no contexto de um curso de Letras. Por se realizar um acompanhamento longitudinal do trabalho com leitura, discutem-se dados de duas alunas, relativos ao gênero crônica, em duas disciplinas acadêmicas. Os resultados comprovam que, para as alunas, são ferramentas de poder conhecer o funcionamento de um dado domínio social, no qual se insere o gênero destinado à leitura e à produção escrita,e desenvolver o metaconhecimento que o constitui, a fim de fazerem uso do letramento crítico e usarem os letramentos dominantes que dele fazem parte, na direção de se assumirem insiders no contexto acadêmico.
A career stage perspective on employees' preferred psychological contract contributions and inducements
Authors: Low Chin Heng , Bordia Prashant
Published: July 2011

The employer–employee relationship is underpinned by a psychological contract, which refers to employee beliefs about the exchange of employee contributions and employer inducements. However, there is limited understanding of how employers can shape psychological contracts to meet employees' needs and aspirations. Meeting these needs starts with an understanding of employees' preferences for psychological contract contributions and inducements. We propose that career stage models can be used to achieve that understanding. Using the career stage models of Dalton, Thompson, and Price (1977) and Super (1957), we derive insights into the preferred contributions and inducements, respectively, at various points of an employee's career lifecycle. These insights will help organizations create desirable psychological contracts and retain valued employees.
A resource-based analysis of organizational turnaround: The contingency role of organizational life stages
Authors: Yeh Quey-Jen , Fang Pin
Published: July 2011

Drawing on the resource-based view (RBV) of the firm, this study proposes two levels of resource action: shedding resources and adding resources as the main two turnaround approaches. Since firms differ in the way they manage their resources over stages of organizational development, this study further analyzes the link between the RBV and organizational life-cycle model to investigate the contingency role of life stages in the turnaround context. The study sample consists of 72 Taiwan firms had ever experienced a successful turnaround. The results indicate that cost-cutting and investment in training and R&D, which represent respectively a shedding and an adding resource action, enable firms to turn around their deteriorating performance. The results also show that R&D investment is more effective for early-stage firms, while cost-cutting is more useful to firms in the late-stage.
Isoprene oxidation mechanisms: measurements and modelling of OH and HO2 over a South-East Asian tropical rainforest during the OP3 field campaign
Authors: Stone D. , Evans M. J. , Edwards P. M. , Commane R. , Ingham T. , Rickard A. R. , Brookes D. M. , Hopkins J. , Leigh R. J. , Lewis A. C. , Monks P. S. , Oram D. , Reeves C. E. , Stewart D. , Heard D. E.
Published: July 2011

Abstract. Forests are the dominant source of volatile organic compounds into the atmosphere, with isoprene being the most significant species. The oxidation chemistry of these compounds is a significant driver of local, regional and global atmospheric composition. Observations made over Borneo during the OP3 project in 2008, together with an observationally constrained box model are used to assess our understanding of this oxidation chemistry. In line with previous work in tropical forests, we find that the standard model based on MCM chemistry significantly underestimates the observed OH concentrations. Geometric mean observed to modelled ratios of OH and HO2 in airmasses impacted with isoprene are 5.32−4.43+3.68 and 1.18−0.30+0.30 respectively, with 68 % of the observations being within the specified variation. We implement a variety of mechanistic changes into the model, including epoxide formation and unimolecular decomposition of isoprene peroxy radicals, and assess their impact on the model success. We conclude that none of the current suggestions can simultaneously remove the bias from both OH and HO2 simulations and believe that detailed laboratory studies are now needed to resolve this issue.
Numerical simulation of flow, H2SO4 cycle and new particle formation in the CERN CLOUD chamber
Authors: Voigtländer J. , Duplissy J. , Stratmann F.
Published: July 2011

Abstract. To study the effect of galactic cosmic rays on aerosols and clouds, the Cosmic Leaving OUtdoor Droplets (CLOUD) project was established. Experiments are carried out at a 26 m3 tank at CERN (Switzerland). In the experiments, the effect of ionising particle radiation on H2SO4 particle formation and growth is investigated. To evaluate the experimental configuration, the experiment was simulated using a coupled multidimensional CFD – particle model (CLOUD-FPM). In the model the coupled fields of gas/vapour species, temperature, flow velocity and particle properties were computed to investigate the tank's mixing state and mixing times. Simulation results show that the mixing state of the tank's contents largely depends on the characteristics of the mixing fans and a 1-fan configuration, as used in first experiments, may not be sufficient to ensure a homogeneously mixed chamber. To mix the tank properly, 2 fans are necessary. The 1/e response times for instantaneous changes of wall temperature and saturation ratio inside the chamber were found to be in the order of few minutes. Particle nucleation and growth was also simulated and particle number size distribution properties of the freshly nucleated particles (particle number, mean size, standard deviation of the assumed log-normal distribution) were found to be mixed over the tank's volume similar to the gas species.
Simultaneous stable isotope analysis of methane and nitrous oxide on ice core samples
Authors: Sapart C. J. , van der Veen C. , Vigano I. , Brass M. , van de Wal R. S. W. , Bock M. , Fischer H. , Sowers T. , Buizert C. , Sperlich P. , Blunier T. , Behrens M. , Schmitt J. , Seth B. , Röckmann T.
Published: July 2011

Abstract. Methane and nitrous oxide are important greenhouse gases which show a strong increase in atmospheric mixing ratios since pre-industrial time as well as large variations during past climate changes. The understanding of their biogeochemical cycles can be improved using stable isotope analysis. However, high-precision isotope measurements on air trapped in ice cores are challenging because of the high susceptibility to contamination and fractionation. Here, we present a dry extraction system for combined CH4 and N2O stable isotope analysis from ice core air, using an ice grating device. The system allows simultaneous analysis of δD(CH4) or δ13C(CH4), together with δ15N(N2O), δ18O(N2O) and δ15N(NO+fragment) on a single ice core sample, using two isotope mass spectrometry systems. The optimum quantity of ice for analysis is about 600g with typical "Holocene" mixing ratios for CH4 and N2O. In this case, the reproducibility (1σ) is 2.1 ‰ for δD(CH4), 0.18 ‰ for δ13C(CH4), 0.51 ‰ for δ15N(N2O), 0.69 ‰ for δ18O(N2O) and 1.12 ‰ for δ15N(NO+fragment). For smaller amounts of ice the standard deviation increases, particularly for N2O isotopologues. For both gases, small-scale intercalibrations using air and/or ice samples have been carried out with other institutes that are currently involved in isotope measurements of ice core air. Significant differences are shown between the calibration scales, but those offsets are consistent and can be corrected for.
Revisiting the humid Roman hypothesis: novel analyses depict oscillating patterns
Authors: Dermody B. J. , de Boer H. J. , Bierkens M. F. P. , Weber S. L. , Wassen M. J. , Dekker S. C.
Published: July 2011

Abstract. Previous studies have proposed that potential vegetation in the Mediterranean maintained a wetter climate during the Roman Period until the initiation of large scale deforestation. The reduction in evapotranspirative fluxes associated with deforestation is suggested to have caused climatic aridification leading to the establishment of the present-day Mediterranean climate. There is also evidence to indicate that during the Roman Period Mediterranean climate was influenced by low frequency fluctuations in sea level pressure over the North Atlantic, termed here: the Centennial North Atlantic Oscillation (CNAO). In order to understand the importance of each of these mechanisms and disentangle their respective signals in the proxy record, we have employed an interdisciplinary approach that exploits a range of tools and data sources. An analysis of archaeological site distribution and historical texts demonstrate that climate did not increase in aridity since the Roman Period. Using an Earth system model of intermediate complexity prescribed with a reconstruction of ancient deforestation, we find that Mediterranean climate was insensitive to deforestation in the Late Holocene. A novel analysis of a composite of proxy indicators of climatic humidity depicts spatial and temporal patterns consistent with the CNAO. The link between the CNAO during the Roman Period and climatic humidity signals manifest in our composite analysis are demonstrated using a modelling approach. Finally, we present evidence indicating that fluctuations in the CNAO contributed to triggering a societal tipping point in the Eastern Mediterranean at the end of the Roman Period.
Simulation of snow distribution and melt under cloudy conditions in an Alpine watershed
Authors: Li H.-Y. , Wang J.
Published: July 2011

Abstract. An energy balance method and remote-sensing data were used to simulate snow distribution and melt in an alpine watershed in northwestern China within a complete snow accumulation-melt period. The spatial energy budgets were simulated using meteorological observations and a digital elevation model of the watershed. A linear interpolation method was used to estimate the daily snow cover area under cloudy conditions, using Moderate Resolution Imaging Spectroradiometer (MODIS) data. Hourly snow distribution and melt, snow cover extent and daily discharge were included in the simulated results. The root mean square error between the measured snow-water equivalent samplings and the simulated results is 3.2 cm. The Nash and Sutcliffe efficiency statistic (NSE) between the measured and simulated discharges is 0.673, and the volume difference (Dv) is 3.9 %. Using the method introduced in this article, modelling spatial snow distribution and melt runoff will become relatively convenient.
Integral quantification of seasonal soil moisture changes in farmland by cosmic-ray neutrons
Authors: Rivera Villarreyes C. A. , Baroni G. , Oswald S. E.
Published: July 2011

Abstract. The measurement of soil moisture at the plot or hill-slope scale is an important link between local vadose zone hydrology and catchment hydrology. However, so far only a few methods are on the way to close this gap between point measurements and remote sensing. One method that could determine an integral soil moisture at this scale is the so called cosmic ray sensing that was introduced to soil hydrology very recently the first time. The present study performed cosmic ray sensing at an agricultural field in a Central European lowland. To test the method it was accompanied by other soil moisture measurements for a summer period with corn crops growing on the field and a later autumn-winter period without crops and a longer period of snow cover. Additionally, meteorological data and above-ground crop biomass was included into the evaluation. Hourly values of cosmic ray sensing showed a high statistical variability. Six-hourly values corresponded well with classical soil moisture measurements, after calibration based on one dry and three wet periods of a few days each. Crop biomass seemed to influence the measurements only to minor degree, opposed to snow cover which has a more substantial impact on the measurements. The latter could be quantitatively related to count rates in two different variants of cosmic ray counters. Overall, our study outlines a procedure to apply the cosmic ray sensing method based on devices now commercially available, without the need for accompanying numerical simulations and suited for longer monitoring periods after initial calibration.
Use of the 3-D scanner in mapping and monitoring the dynamic degradation of soils. Case study of the Cucuteni-Baiceni Gully on the Moldavian Plateau (Romania).
Authors: Romanescu G. , Venedict B. , Cotiuga V. , Asandulesei A.
Published: July 2011

Abstract. The 3-D Scanner, a rapid and precise means of monitoring the dynamics of erosive processes, was used, first of all nationally (Romania), as a new technique of cartography and monitoring the dynamics of soil degradation processes in the Moldavian Plateau. Three sets of measurements took place: in 2008, in 2009 and in 2010, at intervals of exactly one year for the first and six months for the second part. Qualitative and quantitative differences were highlighted. The data obtained were corroborated with precipitation in the area studied. The 3-D scanner has a measurement accuracy of 6 mm. The map highlights the dynamics of gullies developed and may form the basis for the prediction of soil degradation phenomena. The dynamics of the gully and the type of land use show that the phenomenon of erosion of the Moldova Plateau will continue to accelerate. In this case the gully attacked and destroyed an archaeological site of national importance. The rate of advance of the Cucuteni-Baiceni gully is extremely high (10 m/1.6 yr). There are no measures at all to reduce or fight the process of the gully advance. Maximum erosion occurred at the beginning of spring after a winter rich in rainfall, which made the terrain subject to the process of subsidence.
Effect of hydraulic parameters on sediment transport capacity in overland flow over erodible beds
Authors: Ali M. , Sterk G. , Seeger M. , Boersema M. P. , Peters P.
Published: July 2011

Abstract. Sediment transport is an important component of the soil erosion process, which depends on several hydraulic parameters like unit discharge, mean flow velocity, and slope gradient. In most of the previous studies, the impact of these hydraulic parameters on transport capacity was studied for non-erodible bed conditions. Hence, this study aimed to examine the influence of unit discharge, mean flow velocity and slope gradient on sediment transport capacity for erodible beds and also to investigate the relationship between transport capacity and composite force predictors i.e. shear stress, stream power, unit stream power and effective stream power. In order to accomplish the objectives, experiments were carried out using four well sorted sands (0.230, 0.536, 0.719, 1.022 mm). Unit discharges ranging from 0.07 to 2.07 × 10−3 m2 s−1 were simulated inside the flume at four slopes (5.2, 8.7, 13.2 and 17.6 %) to analyze their impact on sediment transport rate. The sediment transport rate measured at the bottom end of the flume by taking water and sediment samples was considered equal to sediment transport capacity, because the selected flume length of 3.0 m was found sufficient to reach the transport capacity. The experimental result reveals that the slope gradient has a stronger impact on transport capacity than unit discharge and mean flow velocity due to the fact that the tangential component of gravity force increases with slope gradient. Our results show that unit stream power is an optimal composite force predictor for estimating transport capacity. Stream power and effective stream power can also be successfully related to the transport capacity, however the relations are strongly dependent on grain size. Shear stress showed poor performance, because part of shear stress is dissipated by bed irregularities, bed form evolution and sediment detachment. An empirical transport capacity equation was derived, which illustrates that transport capacity can be predicted from median grain size, total discharge and slope gradient.
Ultra Low Frequency (ULF) European multi station magnetic field analysis before and during the 2009 earthquake at L'Aquila regarding regional geotechnical information
Authors: Prattes G. , Schwingenschuh K. , Eichelberger H. U. , Magnes W. , Boudjada M. , Stachel M. , Vellante M. , Villante U. , Wesztergom V. , Nenovski P.
Published: July 2011

Abstract. This work presents ground based Ultra Low Frequency (ULF) magnetic field measurements in the frequency range from 10–15 mHz from 1 January 2008 to 14 April 2009. In this time period a strong earthquake series hit the Italian Abruzzo region around L'Aquila with the main stroke of magnitude M = 6.3 on 6 April 2009. In the frame of the South European Geomagnetic Array (SEGMA), a European collaboration runs ULF fluxgate instruments providing continuously magnetic field data recorded in mid- and south Europe. The main scientific objective is the investigation of signal variations due to seismic activity and the discrimination between other natural and human influences. The SEGMA station closest to the L'Aquila earthquake epicenter is L'Aquila observatory located in the epicenter region. For the scientific analysis we extract the nighttime period from 22:00–02:00 UT and determine the power spectral density (PSD) of the horizontal (H) and vertical (Z) magnetic field components and the standardized polarization ratio (Z) over (H). To discriminate local emissions from global geomagnetic effects, data from three SEGMA stations in distances up to 630 km from the epicenter region are analyzed and further compared to the independent global geomagnetic ∑ Kp index. Apart from indirect ionospheric effects, electromagnetic noise could be originated in the lithosphere due to tectonic mechanisms in the earthquake focus. To estimate the amplitude of assumed lithospheric electromagnetic noise emissions causing anomalies in the PSD of the (Z) component, we consider magnetotelluric calculations of the electric crust conductivity in the L'Aquila region. Results found at L'Aquila observatory are interpreted with respect to the lithosphere electrical conductivity in the local observatory region, the ∑ Kp index, and further in a multi station analysis. Possible seismic related ULF anomalies occur ~2 weeks before the main stroke.
Time-lapse slip variation associated with a medium-size earthquake revealed by "repeating" micro-earthquakes: the 1999 Xiuyan, Liaoning, MS = 5.4 earthquake
Authors: Li Y. T. , Wu Z. L. , Peng H. P. , Jiang C. S. , Li G. P.
Published: July 2011

Abstract. We obtained the time-lapse cumulative slip before and after the 29 November 1999, Xiuyan, Liaoning, China, Ms = 5.4 earthquake by using "repeating events" defined by waveform cross-correlation. We used the seismic waveform data from the Liaoning Regional Seismograph Network from June 1999 to December 2006. Two "multiplets" located near the seismogenic fault of the 1999 Xiuyan earthquake and the 4 February 1975, Haicheng Ms = 7.3 earthquake, respectively, were investigated. For the "multiplet" that occurred before and after the 1999 Xiuyan earthquake, apparent pre-shock accelerating-like slip behavior, clear immediate-post-seismic change, and relaxation-like post-seismic change can be observed. As a comparison, for the "multiplet" near the 1975 Haicheng earthquake which occurred a quarter century ago, the cumulative slip appears linear with a much smaller slip rate.
Ultrasound-Guided Fine-Needle Aspiration Biopsy in Unselected Consecutive Patients with Thyroid Nodules
Authors: Kamenov Zdravko A. , Karamfilova Vera N. , Chavrakov Georgi N.
Published: July 2011

The objective was to analyze the results of UG-FNAB, performed in unselected consecutive patients with thyroid nodules. Methods. The UG-FNAB records were analyzed in this retrospective study. Indication for biopsy was the presence of at least one nodule detected by ultrasound. Results. 330 patients at mean age ± SD
48.4 ± 11.2 years; women/men = 12.8/1 were analyzed. From the total 596 nodules found
546 (91.6%) were investigated with 1231 punctures (2.3 per nodule and 3.7 per patient).
Benign solitary nodules had 42.7%, multinodular goiter (MNG) 44.8%, inconclusive 4.8%, and
others 2.1% and malignant nodules 5.5% of the patients (6.6% of solitary and 5.1% of
MNG patients). The risk for a separate nodule in MNG to be malignant was 2.7%.
Conclusions. UG-FNAB is a safe and reliable diagnostic approach for thyroid nodules. It is the method of choice for hypo- and isoechoic not purely cystic solitary nodules, regardless of the nodule size. In MNG, its positive predictive value and diagnostic accuracy are lower. The final decision for regular US monitoring, UG-FNAB of the dominant nodule, multipuncture
UG-FNAB or surgical exploration is one of complex appraisal. We consider UG-FNAB appropriate for most nodules in MNG, according to the above mentioned criteria.
Techniques for Evaluating the Fit of Removable and Fixed Prosthesis
Authors: Shetty Mallika S. , Shenoy K. Kamalakanth
Published: July 2011

The importance of an accurately fitting fixed prosthesis or a removable prosthesis is essential for the success of the restoration. Ill-fitting prosthesis may cause mechanical failures of the prosthesis, implant systems, or biologic complications of the surrounding tissue. There are several causes related to improper seating of the prosthesis. Some of which can be corrected and the others need to be repeated. Hence the clinician must carefully evaluate the adaptation of the prosthesis using the clinical techniques and combination of the available materials and evaluation methods to optimize the fit of prosthesis. This article reviews the various clinical methods that have been suggested for evaluating the fit of the fixed and removable prosthesis.
Genetic Effects of Trabecular Titanium on MG-63 Cell Line: A Genetic Profiling Evaluation
Authors: Vincenzo Sollazzo , Leo Massari , Furio Pezzetti , Ambra Girardi , Francesca Farinella , Vincenzo Lorusso , Silvia Burelli , Hans Rudolf Bloch , Francesco Carinci
Published: July 2011

Pure titanium and titanium alloys are materials widely used in orthopaedics because of their mechanical properties, chemical stability, and biocompatibility. Recently, a new highly porous titanium biomaterial named Trabecular Titanium (TT) has been developed. In this in vitro study, we tested the genetic effects of TT on osteoblast-like cells (MG63) using DNA microarrays technology: cDNA microarrays provides the ability to comparatively analyze mRNA expression of thousands of genes in parallel thus showing activated and repressed genes by the presence of the TT.
Several genes that were significantly up- or downregulated have been identified. Globally, it was demonstrated that TT stimulates osteoblasts proliferation and differentiation, and reduces apoptosis. Therefore, all these effects can contribute to improve the osseointegration of this material. These results encourage the clinical application of Trabecular Titanium to prosthetic devices.
Boundary Layer Mixture Model for a Microbubble Drag Reduction Technique
Authors: Tsai Jing-Fa , Chen Chi-Chuan
Published: July 2011

The boundary mixture model is derived to predict the performance of the microbubble drag reduction technique for a flat plate. The flat plate with a porous material microbubble injecting system and resistance-measuring system are set up to measure the frictional resistance of the flat plate without and with injected microbubbles. The tests are conducted in a water tunnel and a towing tank. The test results show that the boundary mixture model predicts the drag reduction well for the flat plate when testing with injected microbubbles in the water tunnel. However, the boundary mixture model overestimates the drag reduction effect for the flat plate tested in the towing tank. The possible mechanism for the overestimation of drag reduction effect in the towing tank may be due to the different behaviors of microbubbles in the velocity gradient of boundary layer.
Promotion of the Toxic Action of Cyclophosphamide by Digestive Tract Luminal Ammonia in Rats
Authors: Ivnitsky Jury Ju. , Schäfer Timur V. , Rejniuk Vladimir L.
Published: July 2011

To estimate the influence of the digestive tract luminal ammonia pool on acute toxic effects of cyclophosphamide, the dynamics of blood ammonia, glutamine and urea level, symptoms of toxic action and the survival time have been studied in rats, intraperitoneally treated with cyclophosphamide, at the background of the gavage with non-lethal dose of ammonium acetate (12 mmol/kg, i.e., 0.35 LD50). Ammonium acetate enhanced the hyperammonaemic action of cyclophosphamide while promoting its lethal action: the mean survival time decreased 1.5, 2.1, 2.8, or 6.1 times at the background of cyclophosphamide i/p doses 200, 600, 1000, or 1400 mg/kg, respectively. Animals exposed to the combination of toxicants, manifested symptoms which were characteristic of the effect of lethal doses of ammonia salts. These data provide the evidence of the detrimental role of gastrointestinal luminal ammonia in the acute high-dose cyclophosphamide toxicity.
Improving the Isotretinoin Photostability by Incorporating in Microemulsion Matrix
Authors: Patel Mrunali R. , Patel Rashmin B. , Parikh Jolly R. , Patel Bharat G.
Published: July 2011

The present paper demonstrates the increased photostability of isotretinoin when loaded in microemulsion. The photodegradation of isotretinoin, in methanol and microemulsion formulation was studied under direct sun light. The photodegradation process was monitored by UV spectrophotometry. In methanol solution, isotretinoin undergoes complete photodegradation just within a few minutes of light exposure. Isotretinoin incorporated in microemulsion formulation showed an increased stability in comparison to the methanol solutions. In particular for isotretinoin, a residual concentration of 75% was still present after a light irradiance versus a residual value of just 16% measured at the same time in methanol solution. Further, degradation kinetic parameters of isotretinoin-loaded microemulsion formulation were demonstrated increase isotretinoin half-life about five-times in comparison with a methanol solution under a direct sun light.
Smoking and Cervical Cancer
Authors: Fonseca-Moutinho José Alberto
Published: July 2011

Cervical cancer (CC) is the third most common cancer in women worldwide; however, CC is a preventable disease, and much effort should be done to prevent it. Persistence of high-risk HPV infection is the strongest epidemiologic risk factor for CC, however it is not sufficient for development of the disease it cofactors should be present. In 2004; IARC listed cervical cancer among those causally related to smoking. Smoking interferes with incidence and prevalence of HPV infection and is associated with cervical intraepithelial neoplasia and invasive CC. Multiple factors seem to intervene on cervical carcinogenesis related with tobacco, especially by direct local carcinogenic effect and local immunosuppression. Smoking addition is also closely related with other confounding factors, like unfavorable psychosocial events, systemic immunity, contraception, and nutrition, which got difficult epidemiologic evaluation of smoking role on cervical carcinogenesis. Smoking habits should be taken in account in clinical practice and in research concerning CC.
Smoking and Other Interstitial Lung Diseases
Authors: Carlos Carpio , Luis Gómez-Carrera , Rodolfo Álvarez-Sala
Published: July 2011

Cigarette smoking has been implicated in the development of some uncommon respiratory interstitial diseases. Desquamative interstitial pneumonia and respiratory bronchiolitis-associated interstitial lung diseases are characterized by a diffuse alveolar and peribronchiolar filling with macrophages, respectively. Pulmonary Langerhans' cell histiocytosis is a rare interstitial lung disorder characterized by the proliferation of Langerhans' cell forming interstitial infiltrates and nodules that could progress to cavitary nodules. The treatment of these disorders involves smoking cessation and sometimes the use of steroids. High-resolution computed tomography is essential for the characterization of these smoking-related interstitial lung diseases, but frequently it is necessary to create a workgroup composed by pulmonologists, pathologists, and radiologists to diagnosis and treat patients affected with these pathologies.
Preparation and properties of poly(propylene carbonate maleate) microcapsules for controlled release of pazufloxacin mesilate
Authors: Liu Yanfei , Peng Dongming , Huang Kelong , Liu Suqin , Liu Zhenbao
Published: July 2011

A novel biodegradable aliphatic polycarbonate, poly(propylene carbonate maleate) (PPCMA) was synthesized by terpolymerization of carbon dioxide, propylene oxide, and maleic anhydride (MA), using a polymer supported bimetallic complex as catalyst. The utility of PPCMA to encapsulate and control the release of drug pazufloxacin mesilate (PZFX), via microcapsules, was investigated. PPCMA microcapsules containing PZFX were elaborated by solvent evaporation method based on the formation of double W/O/W emulsion. The manufacturing parameters such as the volume ratio of V(PPCMA) : V(PZFX), the concentration of stabilizer gelatin in outer aqueous phase played major roles on microcapsule characters, and were altered to optimize the process parameters. The PPCMA‐PZFX microcapsules were obtained with smooth and spherical surface under optimum condition, the mean diameter of microcapsules was ∼ 2 μm, and the drug loading and drug encapsulation efficiency of the microcapsules were 22.9 ± 1.05% and 82.1 ± 2.03%, respectively. PZFX released from PPCMA microcapsules was found to reach 89.8 ± 2.89% after 36d in a pH 7.4 phosphate‐buffered solution, and the release profile obeyed the Higuchi equation. The results suggest that the new polymer PPCMA provides an alternative to degradable matrix polymers for long‐term sustained releasing drug delivery systems. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effects of acid hydrolysis on microstructure of cured urea‐formaldehyde resins using atomic force microscopy
Authors: Park Byung‐Dae , Jeong Ho‐Won
Published: July 2011

This study investigated the effect of acid hydrolysis on the microstructure of cured urea‐formaldehyde (UF) resins using atomic force microscopy (AFM) to better understand its hydrolytic degradation process which has been known to be responsible for the formaldehyde emission of wood‐based composite panels. The AFM was scanned on both outer surface and facture surfaces of the thin films of cured UF resins that had been exposed to the etching of dilute hydrochloric acid to simulate their hydrolysis process. The AFM images showed two distinctive parts, which were classified as the hard and soft phases in cured UF resins. For the first time, this study reports the presence of thin filament‐like crystalline structures on the fracture surface of cured UF resin. The soft phase of cured UF resins by ammonium chloride was much more easily hydrolyzed than those cured by ammonium sulfate, indicating that hardener types had a great impact on the hydrolytic degradation behavior of cured UF resins. The surface roughness measurement results also supported this result. The results of this study suggested that the soft phase was much more susceptible to the hydrolysis of cured UF resin than the hard phase. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effects of γ‐aminopropyltriethoxylsilane on morphological characteristics of hybrid nylon‐66‐based membranes before electron beam irradiation
Authors: Leo C.P. , Linggawati A. , Mohammad A. W. , Ghazali Z.
Published: July 2011

Nylon‐66 is a typical semicrystalline polymer that can be crosslinked using crosslinking agents and electron beam irradiation. Hybrid nylon‐66‐based membranes are more porous but denser compared to the pure nylon‐66 membrane. Besides that, hybrid nylon‐66 membranes exhibit higher water uptake and severe swelling in water. Si/nylon‐66 membranes were prepared by adding γ‐aminopropyltriethoxylsilane (APTEOS). Crosslinked silica in nylon‐66 membranes is confirmed with high gel content and Fourier transform infrared peaks, but XRD results showed that there is a low crystalline degree in these membranes. The thermal stability of hybrid nylon‐66 membranes is also less affected by APTEOS. The crosslinking agent only improves storage modulus in hybrid nylon‐66 membranes. After irradiation, it is learned that APTEOS improves separation performance of nylon‐66 membranes. However, excessive APTEOS causes the ratio of effective thickness over porosity (Δx/Ak) reduces significantly resulting a lower permeability membrane. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Density functional theory [B3LYP/6‐311G(d,p)] study of a new copolymer based on carbazole and (3,4‐Ethylenedioxythiophene) in their aromatic and polaronic states
Authors: El Malki Z. , Bouzzine S. M. , Bejjit L. , Haddad M. , Hamidi M. , Bouachrine M.
Published: July 2011

We report a theoretical study of a new copolymer based on (Carbazole and Ethylenedioxythiophene)n (n = 1–3) in their neutral and oxidized states, by using B3LYP/6‐311G(d,p) calculations and thus deduce its optoelectronic properties. We discuss the influence of chain length of these properties. We also discuss the experimental UV‐Visible spectrum for (Polyvinylcarbazole‐Poly(3,4‐ethylenedioxythiophene)) (PVK‐PEDOT) copolymer powder for comparison. Conformational analysis shows that there are no big changes in the structural parameters of the oligomers in their neutral form. After oxidation the oligomers become more planar and show a quinoidal character. The electronic states of monomers (Cbz‐Edot) based Carbazole (Cbz) and Ethylenedioxythiophene (Edot), were elucidated by molecular orbital calculations using B3LYP/6‐311G(d,p). The HOMO, LUMO, and gap energies Eg were also deduced for the stable structure of the neutral, polaronic, and bipolaronic forms. Electronic transition energies and oscillator strengths of copolymers were obtained by the ZINDO, TD‐DFT, and CIS methods. Band gaps of the corresponding polymers were obtained by extrapolating oligomer gaps to infinite chain lengths. These results will be compared with the experimental values obtained by optical spectrum. The optoelectronic properties of the (Cbz‐Edot)3 led us to suggest that this oligomer is a good model to reflect those of the parent polymer. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Characterization of in situ prepared nano‐hydroxyapatite/polyacrylic acid (HAp/PAAc) biocomposites
Authors: El‐Bahy G. S. , Abdelrazek E. M. , Allam M. A. , Hezma A. M.
Published: July 2011

Nanoparticles hydroxyapatite (HAp) was prepared via an in situ biomimetic process with polyacrylic acid (PAAc) as a host polymeric material. Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, X‐ray diffraction, thermogravimetric analysis, and differential scanning calorimetry were used to test the physical and chemical characteristics of biocomposites. The formation of HAp is confirmed by energy dispersion X‐ray analysis. Chemical binding between inorganic HAp and PAAc was investigated and discussed. HAp formation was initiated through the interaction of Ca2+ ions with the negative side groups of the polymer surface. The results showed that the biocomposites were formed with good homogeneity and thermal stability. Nanoparticles of HAp were uniformly distributed in the polymeric matrices. The resulting new materials are hoped to be applicable in the biomedical fields. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Natural dyeing with anthocyanins from Hibiscus rosa sinensis flowers
Authors: Vankar Padma S. , Shukla Dhara
Published: July 2011

A new approach for natural dyeing with anthocyanin has been discussed along with a convenient method of extraction. Anthocyanin from Hibiscus flowers has been extracted by developing a method using methanolic solution of 4% citric acid. The new method gave better yield of anthocyanin as compared with methanolic solution of 0.1% hydrochloric acid. It has been also shown that pH of the extract plays an important role on the dye, thus by adjusting the pH of the extract at 4, dyeing of cotton and silk together with metal mordanting gave different colors. The best dyeing results were obtained for stannous mordanted fabrics in terms of fastness properties. The role of metal ion complexation of stannous salt with the dye extract has been confirmed through UV‐Vis and FTIR spectra. Antioxidant activity of the anthocyanin extract seemed to have contributed to enhance the fastness properties of the dyed fabrics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Toughness of HDPE/CaCO3 microcomposites prepared from masterbatch by melt blend method
Authors: Ali Ilias , Elleithy Rabeh
Published: July 2011

In this study, a series of high‐density polyethylene and micro/nanocalcium carbonate polymer composites (HDPE/CaCO3 nanocomposites) were prepared via melt blend technique using a twin screw extruder. Nanocomposite samples were prepared via injection molding for further testing. The effect of % loading of CaCO3 on mechanical and fracture toughness of these composites has been investigated in details. The effect of precrack length variation on the fracture toughness of the composite samples was evaluated, and the morphology of the fractured samples was also observed using scanning electron microscopy (SEM). It was found that increasing the % of CaCO3 and precrack length decreased the fracture toughness. Fracture surface examination by SEM indicated that the diminished fracture properties in the composites were caused by the aglomerization of CaCO3 particles which acted as stress concentrators. A finite element analysis using ANSYS was also carried out to understand the effect of agglomeration size, interaction between the particles and crack tip length on the fracture properties of these composites. Finally, a schematic presentation of the envisioned fracture processes was proposed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Dyeing and fastness properties of polyamide fabrics using some acid‐based monoazo disperse dyes
Authors: Sadeghi‐Kiakhani M. , Gharanjig K. , Arami M. , Khosravi A.
Published: July 2011

A series of monoazo disperse dyes derived from naphthalimide containing butyric acid has been applied on polyamide fabrics. The build up and dyeing properties of these dyes such as leveling property, wash, light, perspiration for alkaline and acidic conditions, and rubbing fastnesses on polyamide fabrics have been investigated. The results showed that the applied dyes are capable of producing red to bluish red hues on polyamide fabrics. Because of the presence of both carboxylic acid and hydroxyl groups on the molecular structure of Dye 3, it showed desired and more strength in respect to other used dyes. Comparing the build up of these dyes to commercial dyes such as disperse red 60 and disperse red 73 revealed that most of the used dyes have higher build up in comparison to the commercial ones. Measurement of fastness properties of dyed samples indicated that they have good wash (4–5), rubbing (4), perspiration (4–5), and heat fastnesses (4–5) and they possess less than moderate light fastness (3–4) on polyamide fabrics. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Effect of hot air aging on properties of EPDM/SmBO3/EVA and EPDM/ATO/EVA composites
Authors: Su Jun , Chen Shuangjun , Zhang Jun
Published: July 2011

Ethylene–propylene–diene rubber (EPDM)/samarium borate (SmBO3)/ethylene‐vinyl acetate (EVA) copolymer and EPDM/antimony‐doped tin oxide (ATO)/EVA composites are aged at 150°C for different intervals. Surface modification is used to improve filler to matrix interphase. The main aim is to investigate the effect of filler type and vinyl acetate (VA) content in EVA on stability of EPDM composites. It is found that acidic ATO particles can lower pH level of EPDM composites and then promote the degradation of acetic acid during aging. Moreover, when VA content exceeds 14 wt %, the instable VA content causes more acetic acids escape during aging. With the increasing of aging time, EPDM/SmBO3 control and EPDM/SmBO3/EVA composites tend to become darker while EPDM/ATO and EPDM/ATO/EVA composites would become yellow. And the color change is correlated well with the variation of carbonyl index. The chemical crosslink points prevent crystals in EVA from melting at aging temperature (150°C), and the variation of crosslink density influences the crystallinity during aging. The tendency of tensile strength is well consistent with that of swelling ratios, and electric properties are correlated with increased polar groups and crystallinity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of a novel phosphorus‐containing compound on the flame retardancy and thermal degradation of intumescent flame retardant polypropylene
Authors: Zhang Shengqiang , Li Bin , Lin Mo , Li Qifei , Gao Suliang , Yi Wei
Published: July 2011

A novel flame retardant, tetra(5,5‐dimethyl‐1,3‐ dioxaphosphorinanyl‐2‐oxy) neopentane (DOPNP), was synthesized successfully, and its structure was characterized by FT‐IR, 1H NMR, and 31P NMR. The thermogravimetric analysis (TGA) results demonstrate that DOPNP showed a good char‐forming ability. Its initial decomposition temperature was 236.4°C based on 1% mass loss, and its char residue was 41.2 wt % at 600°C, and 22.9 wt % at 800°C, respectively. The flame retardancy and thermal degradation behavior of novel intumescent flame‐retardant polypropylene (IFR‐PP) composites containing DOPNP were investigated using limiting oxygen index (LOI), UL‐94 test, TGA, cone calorimeter (CONE) test, and scanning electron microscopy (SEM). The results demonstrate that DOPNP effectively raised LOI value of IFR‐PP. When the loading of IFR was 30 wt %, LOI of IFR‐PP reached 31.3%, and it passed UL‐94 V‐0. TGA results show that DOPNP made the thermal decomposition of IFR‐PP take place in advance; reduced the thermal decomposition rate and raised the residual char amount. CONE results show that DOPNP could effectively decrease the heat release rate peak of IFR‐PP. A continuous and compact char layer observed from the SEM further proved the flame retardance. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Study of photovoltaic performance of host‐guest system comprising photoluminescent polyurethane and rhodamine B dye
Authors: Pokhrel B. , Konwer S. , Dutta A. , Huda M. K. , Ghosh B. , Dolui S. K.
Published: July 2011

The photovoltaic property of Rhodamine B dye embedded into Poly(tolyl‐1,1′‐binaphthyl carbamate) (PU1) and poly(hexamethylene‐1,1′‐binaphthyl carbamate) (PU2) matrices have been evaluated using host‐guest approach. The photoactive layer comprising photoluminescent polymer matrix (PU1 or PU2), Rhodamine B and TiO2 nanoparticles were prepared by spin casting method. The power conversion efficiency (PCE) the photovoltaic devices based on PU1 and PU2 matrices were found to be 0.043% and 0.029%, respectively. PCE of the photovoltaic devices were limited due to low lying highest occupied molecular orbital of PU1 and PU2 polymers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Preparation of the flexible polypyrrole/polypropylene composite fibrous film for electrochemical capacitor
Authors: Jin Ming , Liu Yanyun , Li Yulin , Chang Yunzhen , Fu Dongying , Zhao Hua , Han Gaoyi
Published: July 2011

Polypyrrole (PPy)/polypropylene fibrous membrane (PPF) composite materials with different PPy contents are prepared through in situ chemical oxidation polymerization in the pyrrole atmosphere at room temperature by dissolving the FeCl3·6H2O in methanol and acetonitrile as oxidant. The morphology of the composite is examined by scanning electron microscope (SEM), the conductivities of the composites are measured by convenient four‐probe method, and the properties of the capacitor cells assembled by the obtained PPy/PPF are investigated by cyclic voltammetry (CV), galvanostatic charge/discharge, and electrochemical impedance spectroscopy (EIS) measurements. The results show that the morphology, conductivity, and the capacitor property of the composite are influenced strongly by the solvent of the oxidant. The capacitor assembled by the PPy/PPF prepared by using acetonitrile as the solvent for FeCl3.6H2O can adapt for quick charge/discharge, and exhibit the highest capacitance of about 72.5 F g−1 when the PPy content is about 8.0%. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Characterization of poly(1‐methyl‐1,4‐butanediol‐1,4‐diyl/2,3,4‐trihydro‐5‐methylfuran‐2,5‐diyl) prepared from natural rubber through 2D NMR spectroscopy
Authors: Saito Takayuki , Yamamoto Yoshimasa , Kawahara Seiichi , Ohtake Yoshito
Published: July 2011

Poly(1‐methyl‐1,4‐butanediol‐1,4‐diyl/2,3,4‐trihydro‐5‐methylfuran‐2,5‐diyl) was prepared by epoxidation of deproteinized natural rubber with m‐chloroperbenzoic acid followed by hydrolysis with sulfuric acid. Characterization of the resulting product was performed through FT‐IR, 1H NMR, and 13C NMR spectroscopies. All signals appearing in the 1H and 13C NMR spectra were assigned by distortionless enhancement by polarization transfer (DEPT), quaternary carbon observation (QUAT), correlation spectroscopy (COSY), and heteronuclear multiple quantum correlation (HMQC) measurements. After proving the primary structure of the product, one pot synthesis of poly(1‐methyl‐1,4‐butanediol‐1,4‐diyl/2,3,4‐trihydro‐5‐methylfuran‐2,5‐diyl) from deproteinized natural rubber latex was carried out with peracetic acid and 2‐propanol. The resulting product was characterized by 1H NMR spectroscopy on the basis of the assignments established in this study, and its gas permeability was measured for a practical application as a film. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Synthesis of phosphorus‐containing polyhedral oligomeric silsesquioxanes via hydrolytic condensation of a modified silane
Authors: Zhang Wenchao , Yang Rongjie
Published: July 2011

A simple route to synthesize a new type of phosphorus‐containing polyhedral oligomeric silsesquioxanes (DOPO–POSS) in high yield, by the hydrolytic condensation of a modified silane, is reported. The starting material was a phosphorus‐containing triethoxy silane (DOPO–VTES), which was synthesized by addition reaction between 9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide (DOPO) and vinyl triethoxy silane (VTES). This product was subjected to hydrolytic condensation using an HCl catalyst in methanol. The new types of phosphorus‐containing POSS were obtained and characterized using 1H, 13C, 29Si‐NMR, MALDI‐TOF MS, XRD, DSC, and FTIR. All of these results suggested that the DOPO–POSS were amorphous mixtures of T8, T9(OH), and TGA curve of DOPO–POSS shows that the cage‐like compound has high thermal stability. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation of α‐Amino Acids by Oxidative Oxazoline–Oxazinone Rearrangement–Hydrogenation (OOOH). Scope and Limitations
Authors: Liu Chaomin , Molinski Tadeusz F.
Published: July 2011

The range and scope of the oxidative oxazoline–oxazinone rearrangement–hydrogenation sequence (OOOH)—a short, direct asymmetric synthesis of α‐amino acids from carboxylic acids—was explored. The highest yet reported diastereoselectivity for hydrogenation of the oxazinone CN bond (d.r.=>80:1) is disclosed and rationalized with the aid of ab initio molecular calculations.