bluuebunny/crossref_metadata_2025 huggingface dataset:
A institucionalização do Ensino a Distância no Brasil: o caso da graduação em administração na Universidade Federal do Rio Grande do Norte (UFRN)
Authors: Novais Sueli Menelau de , Fernandes Antônio Sérgio Araújo
Published: April 2011

O Ensino a Distancia (EaD) tem no projeto do Curso Piloto de Administração uma importante iniciativa para sua difusão no país. Este se configura em um consórcio de 25 Instituições de Ensino Superior (IES), apoiado pelo MEC, pela Universidade Aberta do Brasil (UAB) e pelo Banco do Brasil (BB). Este trabalho procura compreender o processo de institucionalização deste na UFRN, identificando as principais ações isomórficas com vistas à sua legitimação. Adotou-se a pesquisa qualitativa, ainda que tenham sido adicionadas técnicas estatísticas como survey, Anova de N fatores e o teste de Tuckey. A pesquisa apontou que as IES que atuam com EaD ainda não constituem um campo organizacional e a criação, bem como o estabelecimento do Curso no contexto da UFRN foram advindos de pressões isomórficas externas, porém apenas as variáveis internas influenciam positivamente à institucionalização do Curso.
A high spatial resolution retrieval of NO2 column densities from OMI: method and evaluation
Authors: Russell A. R. , Perring A. E. , Valin L. C. , Bucsela E. , Browne E. C. , Min K.-E. , Wooldridge P. J. , Cohen R. C.
Published: April 2011

Abstract. We present a new retrieval of tropospheric NO2 vertical column density from the Ozone Monitoring Instrument (OMI) based on high spatial and temporal resolution terrain and profile inputs. We find non-negligible impacts on the retrieved NO2 column for terrain pressure (±20%), albedo (±40%), and NO2 vertical profile (−75%–+10%). We compare our NO2 product, the Berkeley High-Resolution (BEHR) product, with operational retrievals and find that the operational retrievals are biased high (30%) over remote areas and biased low (8%) over urban regions. We validate the operational and BEHR products using boundary layer aircraft observations from the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS-CA) field campaign which occurred in June 2008 in California. Results indicate that columns derived using our boundary layer extrapolation method show good agreement with satellite observations (R2 = 0.65–0.83; N = 68) and provide a more robust validation of satellite-observed NO2 column than those determined using full vertical spirals (R2 = 0.26; N = 5) as in previous work. Agreement between aircraft observations and the BEHR product (R2 = 0.83) is better than agreement with the operational products (R2 = 0.65–0.72). We also show that agreement between satellite and aircraft observations for all products can be further improved (e.g. BEHR: R2 = 0.91) using cloud information from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument instead of the OMI cloud product. These results indicate that much of the variance in the operational products can be attributed to coarse resolution terrain and profile parameters.
Ecology of aerobic anoxygenic phototrophic bacteria along an oligotrophic gradient in the Mediterranean Sea
Authors: Lamy D. , Jeanthon C. , Cottrell M. T. , Kirchman D. L. , Van Wambeke F. , Ras J. , Dahan O. , Pujo-Pay M. , Oriol L. , Bariat L. , Catala P. , Cornet-Barthaux V. , Lebaron P.
Published: April 2011

Abstract. Aerobic anoxygenic phototrophic (AAP) bacteria are photoheterotrophic prokaryotes able to use both light and organic substrates for energy production. They are widely distributed in coastal and oceanic environments and may contribute significantly to the carbon cycle in the upper ocean. To better understand questions regarding links between the ecology of these photoheterotrophic bacteria and the trophic status of water masses, we examined their horizontal and vertical distribution and the effects of nutrient additions on their growth along an oligotrophic gradient in the Mediterranean Sea. Concentrations of bacteriochlorophyll-a (BChl-a) and AAP bacterial abundance decreased from the western to the eastern basin of the Mediterranean Sea and were linked with concentrations of chlorophyll-a, nutrient and dissolved organic carbon. Inorganic nutrient and glucose additions to surface seawater samples along the oligotrophic gradient revealed that AAP bacteria were nitrogen- and carbon-limited in the ultraoligotrophic eastern basin. The intensity of the AAP bacterial growth response generally differed from that of the total bacterial growth response. BChl-a quota of AAP bacterial communities was significantly higher in the eastern basin than in the western basin, suggesting that reliance on phototrophy varied along the oligotrophic gradient and that nutrient and/or carbon limitation favors BChl-a synthesis.
Terrestrial mollusc records from Xifeng and Luochuan L9 loess strata and their implications for paleoclimatic evolution in the Chinese Loess Plateau during marine Oxygen Isotope Stages 24-22
Authors: Wu B. , Wu N. Q.
Published: April 2011

Abstract. Marine Isotope Stages 24-22 is a key period of the Mid-Pleistocene Transition, however, its climate variability is still unclear. The coarse-grained loess unit L9, one of the most prominent units in the Chinese loess stratigraphy, yields a high potential terrestrial record of paleoclimatic and paleoenvironmental changes during this period. In this study, two high-resolution terrestrial mollusc records of L9 loess strata from the Xifeng and Luochuan sequences in the Chinese Loess Plateau were analysed. Our mollusc results show that the MIS 24, the early and late parts of MIS 22 were dominated by cold and dry climate. Relatively mild-humid climate occurred in MIS 23 and the middle part of MIS 22. The climatic conditions at Xifeng region were cooler and more unstable compared to Luochuan region. A comparison of mollusc species composition and other proxies of L9 strata (MIS 24-22) with those of L1 loess units (MIS 4-2) indicates that the L9 loess was not deposited under the most severe glacial conditions in Quaternary climate history as suggested in previous studies. Our study shows that climatic conditions in the Loess Plateau during the L9 loess forming period were similar to that of gentle glacials (MIS 24 and MIS 22) and interglacial (MIS 23), as suggested by the marine δ18O record. Three cooling fluctuations occurred at ~930 ka, 900 ka and 880 ka, which might hint to the global "900 ka cooling event". The "900-ka event" in the Loess Plateau does not seem to be a simple long glaciation, but rather several complex climatic fluctuations superposed on a general cooling trend. The uplift of the Tibetan Plateau and the general cooling experienced by the Earth during this period may have resulted in abundant dust sources and increased dust transport capability, as indicated by increased grain size and the mass accumulation rate of L9 loess.
Seasonal evaluation of the land surface scheme HTESSEL against remote sensing derived energy fluxes of the Transdanubian region in Hungary
Authors: Wipfler E. L. , Metselaar K. , van Dam J. C. , Feddes R. A. , van Meijgaard E. , van Ulft L. H. , van den Hurk B. , Zwart S. J. , Bastiaanssen W. G. M.
Published: April 2011

Abstract. The skill of the land surface model HTESSEL is assessed to reproduce evaporation in response to land surface characteristics and atmospheric forcing, both being spatially variable. Evaporation estimates for the 2005 growing season are inferred from satellite observations of the Western part of Hungary and compared to model outcomes. Atmospheric forcings are obtained from a hindcast run with the Regional Climate Model RACMO2. Although HTESSEL slightly underpredicts the seasonal evaporative fraction as compared to satellite estimates, the mean, 10th and 90th percentile of this variable are of the same magnitude as the satellite observations. The initial water as stored in the soil and snow layer does not have a significant effect on the statistical properties of the evaporative fraction. However, the spatial distribution of the initial soil and snow water significantly affects the spatial distribution of the calculated evaporative fraction and the models ability to reproduce evaporation correctly in low precipitation areas in the considered region. HTESSEL performs weaker in dryer areas. In Western Hungary these areas are situated in the Danube valley, which is partly covered by irrigated cropland and which also may be affected by shallow groundwater. Incorporating (lateral) groundwater flow and irrigation, processes that are not included now, may improve HTESSELs ability to predict evaporation correctly. Evaluation of the model skills using other test areas and larger evaluation periods is needed to confirm the results. Based on earlier sensitivity analysis, the effect of a number of modifications to HTESSEL has been assessed. A more physically based reduction function for dry soils has been introduced, the soil depth is made variable and the effect of swallow groundwater included. However, the combined modification does not lead to a significantly improved performance of HTESSEL.
Towards reconstruction of the flow duration curve: development of a conceptual framework with a physical basis
Authors: Yokoo Y. , Sivapalan M.
Published: April 2011

Abstract. In this paper we investigate the climatic and landscape controls on the flow duration curve (FDC) with the use of a physically-based rainfall-runoff model. The FDC is a stochastic representation of within-year variability of runoff, which arises from the transformation, by the catchment, of within-year variability of precipitation that can itself be characterized by a corresponding duration curve for precipitation (PFDC). Numerical simulations are carried out with the rainfall-runoff model under a variety of combinations of climatic inputs (i.e., precipitation, potential evaporation, including their within-year variability) and landscape properties (i.e., soil type and depth). The simulations indicated that the FDC can be disaggregated into two components, with sharply differing characteristics and origins: the FDC for surface (fast) runoff (SFDC) and the FDC for subsurface (slow) runoff (SSFDC). SFDC closely tracked PFDC and can be approximated with the use of a simple, nonlinear (threshold) filter model. On the other hand, SSFDC tracked the FDC that is constructed from the regime curve (ensemble mean within-year variation of streamflow), which can be closely approximated by a linear filter model. Sensitivity analyses were carried out to understand the climate and landscape controls on each component, gaining useful physical insights into their respective shapes. In particular the results suggested that evaporation from dynamic saturated areas, especially in the dry season, can contribute to a sharp dip at the lower tail of the FDCs. Based on these results, we develop a conceptual framework for the reconstruction of FDCs in ungauged basins. This framework partitions the FDC into: (1) a fast flow component, governed by a filtered version of PFDC, (2) a slow flow component governed by the regime curve, and (3) a correction to SSFDC to capture the effects of high evapotranspiration at low flows.
Brief communication "Monitoring ionospheric variations before earthquakes using the vertical and oblique sounding network over China"
Authors: Xu T. , Wu J. , Zhao Z. , Liu Y. , He S. , Li J. , Wu Z. , Hu Y.
Published: April 2011

Abstract. The problem of earthquake prediction has stimulated the research for correlation between seismic activity and ionospheric anomaly. Many observations have shown the existence of anomaly of critical frequency of ionospheric F-region, foF2, before earthquake onset. Ionospheric sounding has been conducted routinely for more than 60 years in China by the China Research Institute of Radiowave Propagation (CRIRP), and deveoloped a very powerful ability to observe the ionosphere. In this paper, we briefly describe the anomalous variation of the foF2 before Ms8.0 Wenchuan earthquake (occurred on 12 May 2008 at 14:28 LT; 31.00° N, 103.40° E), which is a sign of the great interest arising in the seismo-ionospheric investigation of Chinese researchers. Furthermore, we introduce the routine work on seismo-ionospheric anomaly by the ground based high-resolution ionospheric observation (GBHIO) network comprising 5 vertical and 20 oblique sounding stations.
The Graz seismo-electromagnetic VLF facility
Authors: Schwingenschuh K. , Prattes G. , Besser B. P. , Močnik K. , Stachel M. , Aydogar Ö. , Jernej I. , Boudjada M. Y. , Stangl G. , Rozhnoi A. , Solovieva M. , Biagi P. F. , Hayakawa M. , Eichelberger H. U.
Published: April 2011

Abstract. In this paper we describe the Graz seismo-electromagnetic very low frequency (VLF) facility, as part of the European VLF receiver network, together with the scientific objectives and results from two years operation. After a brief technical summary of the present system – with heritage from a predecessor facility – i.e. hardware, software, operational modes and environmental influences, we discuss results from statistical data and scientific events related to terrestrial VLF propagation over Europe.
Coastal observing and forecasting system for the German Bight – estimates of hydrophysical states
Authors: Stanev E. V. , Schulz-Stellenfleth J. , Staneva J. , Grayek S. , Seemann J. , Petersen W.
Published: April 2011

Abstract. A coastal observing system for Northern and Arctic Seas (COSYNA) aims at construction of a long-term observatory for the German part of the North Sea, elements of which will be deployed as prototype modules in Arctic coastal waters. At present a coastal prediction system deployed in the area of the German Bight integrates near real-time measurements with numerical models in a pre-operational way and provides continuously state estimates and forecasts of coastal ocean state. The measurement suite contributing to the pre-operational set up includes in situ time series from stationary stations, a High-Frequency (HF) radar system measuring surface currents, a FerryBox system and remote sensing data from satellites. The forecasting suite includes nested 3-D hydrodynamic models running in a data-assimilation mode, which are forced with up-to-date meteorological forecast data. This paper reviews the present status of the system and its recent upgrades focusing on developments in the field of coastal data assimilation. Model supported data analysis and state estimates are illustrated using HF radar and FerryBox observations as examples. A new method combining radial surface current measurements from a single HF radar with a priori information from a hydrodynamic model is presented, which optimally relates tidal ellipses parameters of the 2-D current field and the M2 phase and magnitude of the radials. The method presents a robust and helpful first step towards the implementation of a more sophisticated assimilation system and demonstrates that even using only radials from one station can substantially benefit state estimates for surface currents. Assimilation of FerryBox data based on an optimal interpolation approach using a Kalman filter with a stationary background covariance matrix derived from a preliminary model run which was validated against remote sensing and in situ data demonstrated the capabilities of the pre-operational system. Data assimilation significantly improved the performance of the model with respect to both SST and SSS and demonstrated a good skill not only in the vicinity of the Ferry track, but also over larger model areas. The examples provided in this study are considered as initial steps in establishing new coastal ocean products enhanced by the integrated COSYNA-observations and numerical modelling.
Multi-decadal mass loss of glaciers in the Everest area (Nepal Himalaya) derived from stereo imagery
Authors: Bolch T. , Pieczonka T. , Benn D. I.
Published: April 2011

Abstract. Mass loss of Himalayan glaciers has wide-ranging consequences such as changing runoff distribution, sea level rise and an increasing risk of glacial lake outburst floods (GLOFs). The assessment of the regional and global impact of glacier changes in the Himalaya is, however, hampered by a lack of mass balance data for most of the range. Multi-temporal digital terrain models (DTMs) allow glacier mass balance to be calculated. Here, we present a time series of mass changes for ten glaciers covering an area of about 50 km2 south and west of Mt. Everest, Nepal, using stereo Corona spy imagery (years 1962 and 1970), aerial images and recent high resolution satellite data (Cartosat-1). This is the longest time series of mass changes in the Himalaya. We reveal that the glaciers have been significantly losing mass since at least 1970, despite thick debris cover. The specific mass loss for 1970–2007 is 0.32 ± 0.08 m w.e. a−1, however, not higher than the global average. Comparisons of the recent DTMs with earlier time periods indicate an accelerated mass loss. This is, however, hardly statistically significant due to high uncertainty, especially of the lower resolution ASTER DTM. The characteristics of surface lowering can be explained by spatial variations of glacier velocity, the thickness of the debris-cover, and ice melt due to exposed ice cliffs and ponds.
Gavecelt Consensus Statement on the Correct use of Totally Implantable Venous Access Devices for Diagnostic Radiology Procedures
Authors: Bonciarelli Giorgio , Batacchi Stefano , Biffi Roberto , Buononato Massimo , Damascelli Bruno , Ghibaudo Flavio , Orsi Franco , Pittiruti Mauro , Scoppettuolo Giancarlo , Verzè Alessia , Borasi Guido , De Cicco Marcello , Dosio Roberto , Gazzo Paolo , Maso Renzo , Roman Alessandro , Ticha Vladimira , Venier Giacomo , Blackburn Paul , Goossens Godelieve A. , Santolucito Jamie Bowen , Stas Marguerite , Van Boxtel Ton , Vesely Thomas M. , de Lutio Enrico
Published: April 2011

The use of totally implantable venous access devices in radiology may be associated with complications such as occlusion of the system (because of the high density of some contrast), infection (if the port is not handled in aseptic conditions, using proper barrier protections), and mechanical complications due to the high-pressure administration of contrast by automatic injectors (so-called power injector), including extravasation of contrast media into the soft tissues, subintimal venous or myocardial injection, or serious damage to the device itself (breakage of the external connections, dislocation of the non-coring needle, or breakage of the catheter).

The last problem – i.e., the damage of the device from a power injection – is not an unjustified fear, but a reality. A warning by the US Food and Drug Administration of July 2004 reports around 250 complications of this kind, referring to both port and central venous catheters and peripherally inserted central catheter systems, which occurred over a period of several years; in all cases, the damage occurred during the injection of contrast material by means of power injectors for computed tomography or magnetic resonance imaging procedures.

Though the risk associated with the use of ports in radiodiagnostics is thus clear, it has been suggested that administration of the contrast material via the port may have some advantage in terms of image quality, increased comfort for the patient, and maybe more accurate reproducibility of the patient's own follow-up exams. This contention needs to be supported by evidence.

Also, since many cancer patients who need frequent computed tomography studies already have totally implantable systems, it would seem reasonable to try to define how and when such systems may safely be used.

The purpose of this consensus statement is to define recommendations based on the best available evidence, for the safe use of implantable ports in radiodiagnostics.
Incidental Parathyroid Disease during Thyroid Surgery: Should We Remove Them?
Authors: Helme S. , Lulsegged A. , Sinha P.
Published: April 2011

Aim. Despite an incidence of parathyroid “incidentalomas” of 0.2%–4.5%, only approximately 135 cases have been reported in the literature. We present eight patients in whom an incidental abnormal parathyroid gland was found during routine thyroid surgery. We have reviewed the literature and postulate whether these glands could represent further evidence of a preclinical stage of primary hyperparathyroidism.
Methods. A retrospective analysis of all 236 thyroid operations performed by a single surgeon was performed to identify patients in whom abnormal parathyroid tissue was removed at surgery.
Results. 8/236 patients (3.39%) had a single macroscopically abnormal parathyroid gland removed and sent for analysis. Seven patients were found to have histological evidence of a parathyroid adenoma or hyperplasia. None of the patients had abnormal serum calcium detected preoperatively. Postoperatively, four patients had normal calcium, three had temporary hypocalcaemia and one refused followup. No patients had recurrent laryngeal nerve impairment.
Conclusions. Despite the risk of removing a histologically normal gland, we believe that when parathyroid “incidentalomas” are found during surgery they should be excised and sent for histological analysis. We have found this to be a safe procedure with minimal morbidity to the patient.
As the natural history of primary hyperparathyroidism is better understood, these glands found in normocalcaemic patients may in fact represent the early or preclinical phase of the disease. By removing them at the original operation, the patient is saved redo neck surgery with its high complication rate as or when clinically apparent primary hyperparthryoidism develops in the future.
The Management of “Coats' Response” in a Patient with X-Linked Retinitis Pigmentosa—A Case Report
Authors: Bansal Shveta , Saha Niladri , Woon W. H.
Published: April 2011

The management of exudative retinal detachment in Coats disease can be very difficult with variable results. A case is presented of a 12 year old boy who was diagnosed with X-linked retinitis pigmentosa with an associated “Coat's Response”. The patient had a marked reduction in his left visual acuity due to intragel and subhyaloid haemorrhage as well as exudative retinal detachment. This was managed successfully with vitrectomy and endolaser, resulting in clearance of the haemorrhage and flattening of the retina. In our experience endolaser should be considered as viable therapeutic option in the management of this condition.
Oscillatory Thermopower Waves Based on Bi2Te3 Films
Authors: Walia Sumeet , Weber Rodney , Latham Kay , Petersen Phred , Abrahamson Joel T. , Strano Michael S. , Kalantar‐zadeh Kourosh
Published: April 2011

Exothermic chemical reactions that are coupled to Bi2Te3 porous layers, which are deposited onto terracotta or alumina (Al2O3) substrates, are used to produce self‐propagating thermal waves that are guided along the surface. Nitrocellulose is used as the highly reactive chemical. Bi2Te3 is employed because of its large Seebeck coefficient and high electrical conductivity. For the Al2O3 based structures, the thermal conduction of the substrate results in strong oscillations of the output signals. Such thermopower waves produce a power as large as 10 mW and voltages as high as 150 mV. The power per mass ratio of the developed system is quite remarkable, namely, on the order of 1 kW kg−1. Depending on the thermal conductivity of the substrate used, the wave front average propagation velocity is either slow (ca. 0.009 m s−1 for terracotta) or much faster (on the order of 0.4 m s−1 for Al2O3). We have used a mathematical model based on two coupled heat transport equations, in conjunction with the chemical reaction equation, to predict the behavior of the system, which describes the average propagation velocity and the time between oscillation peaks.
Growth of Topological Insulator Bi2Se3 Thin Films on SrTiO3 with Large Tunability in Chemical Potential
Authors: Zhang Guanhua , Qin Huajun , Chen Jun , He Xiaoyue , Lu Li , Li Yongqing , Wu Kehui
Published: April 2011

The growth of high quality, gate‐tunable topological insulator Bi2Se3 thin films on SrTiO3 substrates by molecular beam epitaxy is reported in this paper. The optimized substrate preparation procedures are critical for obtaining undoped Bi2Se3 thin films with sufficiently low carrier densities while maintaining the strong dielectric strength of the substrates. The large tunability in chemical potential is manifested in the greatly enhanced longitudinal resistivity and the reversal of the sign of the Hall resistivity at negative back‐gate voltages. These thin films provide a convenient basis for fabrication of hybrid devices consisting of gate‐tunable topological insulators and other materials such as a superconductor and a ferromagnet.
Critical Property in Relaxor‐PbTiO3 Single Crystals – Shear Piezoelectric Response
Authors: Li Fei , Zhang Shujun , Xu Zhuo , Wei Xiaoyong , Shrout Thomas R.
Published: April 2011

The shear piezoelectric behavior in relaxor‐PbTiO3 (PT) single crystals is investigated with regard to the crystal phase. High levels of shear piezoelectric activity, d15 or d24 >2000 pC N−1, are observed for single‐domain rhombohedral (R), orthorhombic (O), and tetragonal (T) relaxor‐PT crystals. The high piezoelectric response is attributed to a flattening of the Gibbs free energy at compositions close to the morphotropic phase boundaries, where polarization rotation is easily accomplished by applying a perpendicular electric field. The shear piezoelectric behavior of perovskite ferroelectric crystals is discussed with respect to ferroelectric‐ferroelectric phase transitions and the dc bias field using a phenomenological approach. The relationship between the single‐domain shear piezoelectric response and piezoelectric activities in domain‐engineered configurations is also given in this paper. From an application viewpoint, the temperature and ac‐field drive stability for shear piezoelectric responses are investigated. A temperature‐independent shear piezoelectric response (d24, in the range of ‐50 °C to the O‐T phase‐transition temperature) is thermodynamically expected and experimentally confirmed in orthorhombic relaxor‐PT crystals; a relatively high ac‐field drive stability (5 kV cm−1) is obtained in manganese‐modified relaxor‐PT crystals. For all thickness shear vibration modes, the mechanical quality factor Qs are less than 50, corresponding to the facilitated polarization rotation.
Carbon Nanoparticles on Carbon Fabric for Flexible and High‐Performance Field Emitters
Authors: Yuan Longyan , Tao Yuting , Chen Jian , Dai Junjie , Song Ting , Ruan Mingyue , Ma Zongwei , Gong Li , Liu Kang , Zhang Xianghui , Hu Xuejiao , Zhou Jun , Wang Zhong Lin
Published: April 2011

Carbon nanoparticles (CNPs) are grown on flexible carbon fabric via a simple and low‐cost flame synthesis process. The entire struture of the carbon fabric substrate retains its high flexibility after the growth of CNPs and can even be rolled‐up and twisted to a large degree without affecting the electric characteristics. No appreciable changes in the conductance can be observed under different bending curvatures after hundreds of bending cycles. The thermal conductivity of the carbon fabric with CNPs is about 2.34 W m−1 K−1, about one order of magnitude higher than that of most polymer substrates. The field emitter fabricated using the structure has a low threshold electric field of around 2.8 V μm−1, and a high field emission current density of 108 mA cm−2, which is about two to four orders of magnitude higher than that of most polymer substrate‐based flexible CNT field emitters. These results indicate that CNPs on carbon fabric have potential applications in flexible electronics devices and displays.
Nanoscale Assembly in Biological Systems: From Neuronal Cytoskeletal Proteins to Curvature Stabilizing Lipids
Authors: Safinya Cyrus R. , Raviv Uri , Needleman Daniel J. , Zidovska Alexandra , Choi Myung Chul , Ojeda‐Lopez Miguel A. , Ewert Kai K. , Li Youli , Miller Herbert P. , Quispe Joel , Carragher Bridget , Potter Clinton S. , Kim Mahn Won , Feinstein Stuart C. , Wilson Leslie
Published: April 2011

The review will describe experiments inspired by the rich variety of bundles and networks of interacting microtubules (MT), neurofilaments, and filamentous‐actin in neurons where the nature of the interactions, structures, and structure‐function correlations remain poorly understood. We describe how three‐dimensional (3D) MT bundles and 2D MT bundles may assemble, in cell free systems in the presence of counter‐ions, revealing structures not predicted by polyelectrolyte theories. Interestingly, experiments reveal that the neuronal protein tau, an abundant MT‐associated‐protein in axons, modulates the MT diameter providing insight for the control of geometric parameters in bio‐ nanotechnology. In another set of experiments we describe lipid‐protein‐nanotubes, and lipid nano‐ tubes and rods, resulting from membrane shape evolution processes involving protein templates and curvature stabilizing lipids. Similar membrane shape changes, occurring in cells for the purpose of specific functions, are induced by interactions between membranes and proteins. The biological materials systems described have applications in bio‐nanotechnology.
Nanoscale Materials for Tackling Brain Cancer: Recent Progress and Outlook
Authors: Rozhkova Elena A.
Published: April 2011

This article reports on recent progress in the development of advanced nanoscale photoreactive, magnetic and multifunctional materials applicable to brain cancer diagnostics, imaging, and therapy, with an emphasis on the latest contributions and the novelty of the approach, along with the most promising emergent trends.
Study of effect of temperature gradient on solid dissolution process under action of transverse rotating magnetic field
Authors: Rakoczy Rafał
Published: April 2011

The study of effect of the transverse rotating magnetic field on the dissolution process of rock‐salt sample is the main purpose of this work. Moreover, the experimental study of the influence of the temperature gradient between the surface of sample and the solvent temperature on this process is presented in this article. The results of investigations are worked out by means of the novel type dimensionless equations including standard and magnetic numbers. The obtained results are compared with the data given in the previous literature. © 2011 American Institute of Chemical Engineers AIChE J, 2012
Microwave combination heating: Coupled electromagnetics‐ multiphase porous media modeling and MRI experimentation
Authors: Rakesh Vineet , Datta Ashim K. , Walton Jeffrey H. , McCarthy Kathryn L. , McCarthy Michael J.
Published: April 2011

The work includes development of a multiphase porous media model and magnetic resonance imaging (MRI) experiments to study microwave combination heating. Combination of electromagnetic, convective and radiant heating was considered. The material being heated was modeled as a hygroscopic porous medium with different phases: solid matrix, water and gas, and included pressure driven flow, binary diffusion and phase change. The three‐dimensional transport model was fully coupled with electromagnetics to include the effect of variable properties. MRI was used to obtain spatial temperature and moisture distributions to validate the model. The model demonstrated that high and low moisture materials behave differently under different combinations of heating and general guidelines for combining heating modes were obtained. Low moisture materials can be heated effectively using higher microwave power which is not possible in high moisture material. Cycling of microwave was found to be useful in distribution of excessive volumetric heat generated by microwaves. © 2011 American Institute of Chemical Engineers AIChE J, 2012
An efficient FeCl3‐promoted O‐alkyl cleavage of esters to carboxylic acids
Authors: Lian Xiaoyan , Fu Shaomin , Ma Tongmei , Li Shunbin , Zeng Wei
Published: April 2011

A reliable and practical procedure for FeCl3‐promoted ester cleavage has been developed. Lewis acids including TiCl4, ZnO and FeCl3 etc. were investigated as promoters for O‐alkyl cleavage of carboxylic acid ester. Under optimal reaction conditions, FeCl3 (1.5 equiv.) was found to possess the highest activity and efficiently enhanced dealkylation of aryl esters, alkyl esters and aromatic heterocyclic esters to give their corresponding carboxylic acids in 54–98% yield, the method provides a complementary access to dealkylation of ester under neutral condition. Copyright © 2011 John Wiley & Sons, Ltd.
Preparation of silicalite–polyamide composite membranes for desalination
Authors: Li Dan , He Li , Dong Dehua , Forsyth Maria , Wang Huanting
Published: April 2011

Silicalite–polyamide composite membranes were synthesized via interfacial polymerization on a commercial polysulfone substrate, for the purpose of studying the effect of the addition of silicalite nanocrystals on the desalination property of polyamide membrane. The scanning electron microscopy (SEM) images showed that both plain polyamide membrane and silicalite–polyamide composite membranes exhibited rough surface morphology which is similar to the commercial polyamide membranes. The existence of silicalite nanocrystals in the silicalite–polyamide composite membrane was confirmed by energy dispersive X‐ray spectroscopy (EDXS) and high‐resolution transmission electron microscopy (HRTEM). The effect of loading of silicalite nanocrystals on the desalination property of membranes was examined. By increasing the loading of silicalite nanocrystals, the water flux of silicalite–polyamide composite membranes increased, whereas the salt selectivity decreased significantly. Plain polyamide membrane had salt rejection of 98.1% and a flux of 5.07 × 10−7 m3/m2·s, whereas the silicalite–polyamide composite membrane, prepared from trimesoyl chloride (TMC)–hexane with 0.5% (w/v) silicalite, had a water flux of 2.74 × 10−6 m3/m2·s and NaCl rejection of 50% at a feed pressure of 34.48 bar by using 2000 ppm salt solution as the feed. The transport mechanisms of the silicalite–polyamide composite membranes were discussed. © 2011 Curtin University of Technology and John Wiley & Sons, Ltd.
An efficient electroluminescence copolymer based on vinyl‐linked donor–acceptor system
Authors: Qi Zheng‐Jian , Wei Bin , Sun Yue‐Ming , Hong Man‐Xin , Tang Lan‐Lan , Yin Shou‐Gen
Published: April 2011

Using copolymerization functionalization, poly[3,4‐dioctyloxythiophene‐alt‐2,5‐bis(4‐vinylphenyl)‐1,3,4‐oxadiazole] (P3,4DOOTV‐OXD) combining electrochemical properties of poly(3,4‐dioctyloxythiophene) (P3,4DOOT, donor) and 1,3,4‐oxadiazole (OXD, acceptor) was synthesized through Heck reaction and evaluated with 1H‐NMR, FTIR, gel permeation chromatography (GPC), UV–vis spectroscopy, photoluminescence (PL), and electroluminescence (EL) spectra. This D/A alternating copolymer, with regiosymmetrical 3,4‐dioctyloxythiophene, has good solubility in common organic solvents. The optical properties investigations showed that the band‐gap energy of P3,4DOOTV‐OXD is 10% higher than that of P3,4DOOT (2.27 eV) at 2.52 eV in solid film. However, the photoluminescence (PL) quantum yield is as high as 57.4%, > two times more than that of homopolymer P3,4DOOT in CHCl3 solution, and displays bright green‐yellow luminescence (518 nm) in solution and yellow (542 nm) in solid film. Cyclic voltammogram indicated that the copolymer has bipolar properties, and the band gap energy (Eg) calculated based on the cyclic voltammogram is consistent with that deduced from the absorption spectra at 2.40 eV. By using indium‐tin oxide (ITO) as the anode, poly(ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonate) (PSS) as the hole‐injection layer, P3,4DOOTV‐OXD as the emitter and aluminum (Al) as the cathode, double‐layer device with the structure of [ITO/PEDOT: PSS (50 nm)/polymer/Al (130 nm)] shows typical diode characters and exhibit bright yellow electroluminescence (562–552 nm) under the forward bias. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Antimicrobial activity of some new 4‐arylazo‐3‐methylthiophene disperse dyes on polyester fabrics
Authors: Gafer Hatem E. , Abdel‐Latif Ehab
Published: April 2011

A series of novel 4‐arylazo‐3‐methylthiophenes was synthesized by the heterocyclization of 2‐arylhydrazono‐2‐acetyl thioacetanilide derivatives with a variety of α‐halogenated reagents, such as chloroacetone, phenacyl bromide, ethyl chloroacetate, and chloroacetonitrile. The structures of the synthesized thiophene derivatives were confirmed by ultraviolet–visible, IR, and 1H‐NMR spectroscopic techniques and elemental analysis. The synthesized dyes were applied to polyester fabrics as disperse dyes, and their fastness properties were evaluated. The dyed polyester fabrics displayed antibacterial efficacy against Gram‐positive (Staphylococcus aureus) and Gram‐negative (Escherichia coli) bacteria. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Rheological aspects of microbial hyaluronic acid
Authors: Pires Aline M. B. , Santana Maria H. A.
Published: April 2011

The rheological properties of the hyaluronic acid (HA) produced by the cultivation of Streptococcus zooepidemicus ATCC 39920 in synthetic medium at constant pH of 7.0 were determined. Relevant characteristics of the biopolymer as its pureness related to proteins (0.44 mg of protein per gram of HA) and its average molar weight (4.0 × 106 Da) were also determined. Experimental data in steady shear (flow curves) have been correlated with the Cross model, which described the apparent viscosity shear rate data well mainly at concentrations higher than 50 mg mL−1.The concentration dependence of specific viscosity showed two linear regimes that intercept at critical overlap concentration (c*) equal to 4 mg mL−1. The storage (G′) and loss (G″) moduli increasing along the HA concentration and estimates out of the studied range indicate that a crossover frequency decreased with the increasing concentration of HA. The high concentration dependence of G′ as well as the deviations of the Cox‐Merz rule for most of the HA concentrations indicate the hyperentangled properties for the HA chains, which could be visualized through atomic force microscopy images even at low concentrations as 0.01 mg mL−1. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Melt processing of poly(L‐lactic acid) in the presence of organomodified anionic or cationic clays
Authors: Katiyar Vimal , Gerds Nathalie , Koch Christian Bender , Risbo Jens , Hansen Hans Christian B. , Plackett David
Published: April 2011

Poly(L‐lactic acid) (PLA) films are in use for various types of food packaging; however, a wider range of applications would be possible if the barrier properties of these films could be improved. To make such improvements, combinations of PLA with two nanofillers, laurate‐intercalated Mg‐Al layered double hydroxide (LDH‐C12) and a cationic organomodified montmorillonite (MMT) clay (Cloisite® 30B), were investigated. The dispersion of these fillers in PLA by melt processing was explored using two methods, either by mixing the nanofillers with PLA granulate immediately before extrusion or by preparation and subsequent dilution of PLA‐nanofiller masterbatches. After melt processing of these materials, PLA molecular weight, thermal stability, film transparency, morphology, and permeability characteristics were determined. Direct addition of LDH‐C12 drastically reduced the PLA molecular weight. Although this reduction in molecular weight was still very significant, it was less when a PLA/LDH‐C12 masterbatch was processed. In contrast, there was no significant reduction in PLA molecular weight when processing with Cloisite® 30B. However, film transparency was compromised when either LDH or MMT nanofillers were used. Evidence from DSC analyses showed a significant increase in heat of fusion when LDH‐C12 was dispersed in PLA compared with Cloisite® 30B, likely indicating a difference in nucleating properties. Complementary optical purity analyses suggested that racemization as a result of processing could influence the PLA crystallinity as determined by DSC in certain cases. A reduction in thermal stability when incorporating LDH‐C12 could be a direct result of PLA molecular weight reduction. XRD and TEM analyses showed that both Cloisite® 30B‐ and LDH‐C12‐based PLA composites yielded exfoliated and intercalated morphologies, but nanofiller agglomeration was also seen when LDH‐C12 was used. PLA/Cloisite® 30B nanocomposite films exhibited significant enhancement in oxygen and water vapor barrier properties, but no such improvement was found in PLA/LDH‐C12 nanocomposite films. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Poly(lactic acid)/layered silicate nanocomposite films: Morphology, mechanical properties, and effects of γ‐radiation
Authors: Dadbin Susan , Naimian Faranak , Akhavan Azam
Published: April 2011

Poly(Lactic acid) (PLA)‐layered silicate nanocomposite films were prepared by solvent casting method. The films were irradiated with Co60 radiation facility at dose of 30 kGy. The effect of γ irradiation on mechanical properties of the neat PLA and nanocomposites was evaluated by data obtained from tensile testing measurements. The tensile strength of the irradiated PLA films increased with addition of 1 wt % triallyl cyanurate indicating crosslink formation. Significant ductile behavior was observed in the PLA nanocomposites containing 4 pph of nanoclay. Incorporation of nanoclay particles in the PLA matrix stimulated crystal growth as it was studied by differential scanning calorimetry. The morphology of the nanocomposites characterized by transmission electron microscopy and X‐ray diffraction revealed an exfoliated morphology in the PLA nanocomposite films containing 4 pph of nanoclay. Only very small changes were observed in the chemical structure of the irradiated samples as it was investigated by Fourier transform infrared spectroscopy. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and solubility properties of chitin acetate/butyrate copolymers
Authors: Draczynski Zbigniew
Published: April 2011

In this article, syntheses of chitin acetate/butyrate copolymers with different contents of acetyl residue in polymer chain have been described. Chitin copolymers as well as pure diacetylchitin (DAC) and dibutyrylchitin (DBC) have been obtained in the reaction of shrimp chitin with mixture of acetic and butyric anhydrides used in different proportion. Reactions have been carried out under heterogeneous condition with perchloric acid (PA) used as a catalyst of reaction. Chemical structure of DAC, DBC, and co‐(acetate/butyrates) was confirmed in 1H‐NMR as well as in Fourier transform infrared (FTIR) investigations. Results of 1H‐NMR investigation showed that in all cases of chitin esterification carried out at applied conditions, final products with summary degree of substitution (DP) closed to 2 have been obtained. Prepared chitin acetate/butyrate copolymers with high degree of polymerization (DP) (based on value of intrinsic viscosity) with varying amount of acetyl groups from 0.24 to 1.29 have been formed depending on the mixture composition of acetic and butyric acid anhydrides. All obtained co‐(acetate/butyrates) are soluble in organic solvents such as dimethylformamide (DMF), dimethylsulfoxide (DMSO), dimethylacetamide (DMAc) as well as ethanol and form strong transparent films. It was stated that solubility of obtained chitin copolyesters slightly decreases with increase of the acetyl groups content in polymer chain, but it is still high enough to be taken into consideration for eventual production of fibers or scaffolds. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Photogeneration of gelatinous networks from pre‐existing polymers
Authors: Carroll Gregory T. , Devon Triplett L. , Moscatelli Alberto , Koberstein Jeffrey T. , Turro Nicholas J.
Published: April 2011

In this manuscript we report the crosslinking of pre‐existing macromolecules in solution through the use of photoactive benzophenone chromophores. We show that a bifunctional crosslinker composed of two benzophenone chromophores as well as a single benzophenone chromophore crosslink poly (butadiene) and poly (ethylene oxide) in solution to form insoluble gels when irradiated with UV light. The molecular weight between crosslinks of the photogenerated gels was compared for the two crosslinkers, for an equivalent amount of benzophenone chromophores in each solution, by measuring the swelling ratio of the gels formed. Gels formed from the bifunctional benzophenone crosslinker were shown to contain more than twice as many crosslinks compared to gels formed from the crosslinker composed of a single benzophenone chromophore. EPR measurements of a nitroxide derivative absorbed into the gels further supported a higher crosslink density for the gels formed from the bifunctional benzophenone crosslinker. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and swelling characteristics of responsive carboxybetaine gel
Authors: Tarannum Nazia , Singh Meenakshi
Published: April 2011

A polyimminium gel, Dimedone‐[N, N′ melaminium] butyrocarboxylate copolymer, comprising of zwitterionic carboxybetaine repeat units was synthesized via a catalyst free facile polycondensation approach. The polymer was studied for its photoluminescence, thermal, and swelling behavior. Swelling behavior was investigated in different solvent mixtures as well as in pure solvents. The extent of swelling was dictated by solvent composition, such as dielectric constant, pH, ionic strength, and other variables for instance, temperature and crosslinking density. Gel was soluble in alkali and could be regenerated on treatment with an acid. This pH responsive behavior could find various industrial applications, especially in wastewater treatment. A preliminary study on sorption of dyes was also carried out. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.
Anti‐C1q antibodies are associated with systemic lupus erythematosus global activity but not specifically with nephritis: A controlled study of 126 consecutive patients
Authors: Katsumata Yasuhiro , Miyake Kohei , Kawaguchi Yasushi , Okamoto Yuko , Kawamoto Manabu , Gono Takahisa , Baba Sayumi , Hara Masako , Yamanaka Hisashi
Published: April 2011

Objective

Several studies have shown that anti‐C1q antibodies correlate with the occurrence and activity of nephritis in systemic lupus erythematosus (SLE). However, the significance of anti‐C1q antibodies in SLE has not been fully characterized. The aim of this study was to investigate associations between anti‐C1q antibodies and clinical and serologic parameters of SLE.

Methods

An enzyme‐linked immunosorbent assay kit was used to measure anti‐C1q antibodies in the sera of 126 consecutive patients with active SLE who were admitted to our university hospital from 2007 through 2009. Sera obtained from patients with high titers of anti‐C1q antibodies at the initial evaluation (n = 20) were reevaluated following treatment. Control sera were obtained from patients with other autoimmune diseases and from normal healthy control subjects (n = 20 in each group). Associations between anti‐C1q antibodies and clinical and serologic parameters of SLE were statistically analyzed.

Results

Anti‐C1q antibodies were detected in the sera of 79 of 126 patients with SLE. The prevalence and titers of anti‐C1q antibodies were significantly (P < 0.0001) higher in SLE patients than in patients with rheumatoid arthritis, patients with systemic sclerosis, and normal healthy control subjects. The prevalence and titers of anti‐C1q antibodies were not significantly associated with active lupus nephritis (P = 0.462 and P = 0.366, respectively). Anti‐C1q antibody titers were significantly correlated with SLE Disease Activity Index 2000 scores and the levels of anti–double‐stranded DNA antibodies, C3, C4, CH50, and C1q (P < 0.0001 for all comparisons). Moreover, anti‐C1q antibody titers significantly decreased as clinical disease was ameliorated following treatment (P = 0.00097).

Conclusion

These findings indicate that anti‐C1q antibodies are associated with SLE global activity but not specifically with active lupus nephritis.