bluuebunny/crossref_metadata_2025 huggingface dataset:
A Systematic Review and Analysis of Reporting Quality of Studies of Germline Genetic Variants Influencing Susceptibility to Nonmedullary Thyroid Cancer
Authors: Ritchie Judith E , Balasubramanian Sabapathy P
Published: March 2011

Genetic susceptibility makes a significant contribution to many multifactorial diseases, such as cancer. Genetic variants have been associated with medullary thyroid cancer but their role in nonmedullary thyroid cancer (NMTC) has not been clearly characterized. Although many published reports have evaluated association between some genetic variants and NMTC, a comprehensive assessment has not been done and the quality of reporting of these studies has not been evaluated. In this study, we report the results of a systematic review of published case-control studies looking at the association of polymorphisms with the susceptibility to nonmedullary thyroid cancer and an assessment of quality of study design, implementation and interpretation.

Methods

A systematic review of the existing literature was carried out, identifying studies through a search of the Medline literature via PubMed and through scanning of references of these papers. These papers were then subject to an assessment of quality of reporting using a scoring system modified from previously published criteria.

Results

50 studies published between 1997 and 2010 were included. These studies included 916 polymorphisms across 62 genes involved in a diverse range of cellular processes using 10,704 cases and 27,707 controls. The median quality score was 70.4% (range 52-93%). Areas of strength and weaknesses in study reporting were identified.

Conclusions

Research on the genetic susceptibility to nonmedullary thyroid cancer is sparse. Published studies are of suboptimal quality, have analyzed few variants and positive findings have not been replicated. Adherence to recently published guidelines on methodology should be encouraged. A consortium led approach involving multiple centers, including large numbers of patients in well-defined study protocols is required to investigate this subject comprehensively.
Importance of secondary sources in the atmospheric budgets of formic and acetic acids
Authors: Paulot F. , Wunch D. , Crounse J. D. , Toon G. C. , Millet D. B. , DeCarlo P. F. , Vigouroux C. , Deutscher N. M. , González Abad G. , Notholt J. , Warneke T. , Hannigan J. W. , Warneke C. , de Gouw J. A. , Dunlea E. J. , De Mazière M. , Griffith D. W. T. , Bernath P. , Jimenez J. L. , Wennberg P. O.
Published: March 2011

Abstract. We present a detailed budget of formic and acetic acids, two of the most abundant trace gases in the atmosphere. Our bottom-up estimate of the global source of formic and acetic acids are ~1200 and ~1400 Gmol yr−1, dominated by photochemical oxidation of biogenic volatile organic compounds, in particular isoprene. Their sinks are dominated by wet and dry deposition. We use the GEOS-Chem chemical transport model to evaluate this budget against an extensive suite of measurements from ground, ship and satellite-based Fourier transform spectrometers, as well as from several aircraft campaigns over North America. The model captures the seasonality of formic and acetic acids well but generally underestimates their concentration, particularly in the Northern midlatitudes. We infer that the source of both carboxylic acids may be up to 50% greater than our estimate and report evidence for a long-lived missing secondary source of carboxylic acids that may be associated with the aging of organic aerosols. Vertical profiles of formic acid in the upper troposphere support a negative temperature dependence of the reaction between formic acid and the hydroxyl radical as suggested by several theoretical studies.
Black carbon in the atmosphere and snow, from pre-industrial times until present
Authors: Skeie R. B. , Berntsen T. , Myhre G. , Pedersen C. A. , Ström J. , Gerland S. , Ogren J. A.
Published: March 2011

Abstract. The distribution of black carbon (BC) in the atmosphere and the deposition of BC on snow surfaces since pre-industrial time until present are modelled with the Oslo CTM2 model. The model results are compared with observations including recent measurements of BC in snow in the Arctic. The global mean burden of BC from fossil fuel and biofuel sources increased during two periods. The first period, until 1920, is related to increases in emissions in North America and Europe, and the last period after 1970 are related mainly to increasing emissions in East Asia. Although the global burden of BC from fossil fuel and biofuel increases, in the Arctic the maximum atmospheric BC burden as well as in the snow was reached in 1960s, with a slight reduction thereafter. The global mean burden of BC from open biomass burning sources has not changed significantly since 1900. With current inventories of emissions from open biomass sources, the modelled burden of BC in snow and in the atmosphere north of 65° N is small compared to the BC burden of fossil fuel and biofuel origin. From the concentration changes radiative forcing time series due to the direct aerosol effect as well as the snow-albedo effect is calculated for BC from fossil fuel and biofuel. The calculated radiative forcing in 2000 for the direct aerosol effect is 0.35 W m−2 and for the snow-albedo effect 0.016 W m−2. Due to a southward shift in the emissions there is an increase in the lifetime of BC as well as an increase in normalized radiative forcing, giving a change in forcing per unit of emissions of 26% since 1950.
Seasonal variations and vertical features of aerosol particles in the Antarctic troposphere
Authors: Hara K. , Osada K. , Nishita-Hara C. , Yamanouchi T.
Published: March 2011

Abstract. Tethered balloon-borne aerosol measurements were conducted at Syowa Station, Antarctica during the 46th Japanese Antarctic expedition (2005–2006). The CN concentration reached a maximum in the summer, although the number concentrations of fine particles (Dp > 0.3 μm) and coarse particles (Dp > 2.0 μm) increased during the winter-spring. The CN concentration was 30–2200 cm−3 near the surface (surface – 500 m) and 7–7250 cm−3 in the lower free troposphere (>1500 m). During the austral summer, higher CN concentration was often observed in the lower free troposphere, where the number concentrations in fine and coarse modes were remarkably lower. The frequent appearance of higher CN concentrations in the free troposphere relative to continuous aerosol measurements at the ground strongly suggests that new particle formation is more likely to occur in the lower free troposphere in Antarctic regions. Seasonal variations of size distribution of fine-coarse particles show that the contribution of the coarse mode was greater in the winter-spring than in summer because of the dominance of sea-salt particles in the winter-spring. The number concentrations of fine and coarse particles were high in air masses from the ocean and mid-latitudes. Particularly, aerosol enhancement was observed not only in the boundary layer but also in the lower free troposphere during and immediately after Antarctic haze events occurring in May, July, and September.
Verification and comparison of probabilistic precipitation forecasts using the TIGGE data in the upriver of Huaihe Basin
Authors: Zhao L.-N. , Tian F.-Y. , Wu H. , Qi D. , Di J.-Y. , Wang Z.
Published: March 2011

Abstract. The precipitation forecasts of three ensemble prediction systems (EPS) and two multi-model ensemble prediction systems (MM EPS) were assessed by comparing with observations from 19 rain gauge stations located in the Dapoling-Wangjiaba sub-catchment of Huaihe Basin for the period from 1 July to 6 August 2008. The sample Probabilistic Distribution Functions (PDF) of gamma distribution, the Relative Operating Characteristic (ROC) diagrams, the percentile precipitation and a heavy rainfall event are analyzed to evaluate the performances of the single and multi-model ensemble prediction system (EPS). The three EPS were from the China Meteorological Administration (CMA); the United States National Centre for Environment Predictions (NCEP); and the European Centre for Medium-Range Weather Forecasts (ECMWF), all were obtained from the TIGGE-CMA archiving centre (THORPEX Interactive Grand Global Ensemble, TIGGE). The MM EPS were created using the equal weighting method for every ensemble member over the test area, the first ( MM-1) consisted of all three EPS, the second (MM-2) consisted of the ECMWF and NCEP EPS. The results demonstrate the level of correspondence between deterioration in predictive skill and extended lead time. Compared with observations and with a lead time of one day, ECMWF performs a little better than other centre's. With over five days in advance, all the three EPS and the two MM EPS don't give reliable probabilistic precipitation forecasts. Both MM EPS can outperform CMA and NCEP for most of the forecasted days, but still perform a little worse than ECMWF. Though variation of daily percentile precipitation and ROC areas show MM-2 outperforms MM-1, gamma distribution indicates much similar performances for all 10-day forecast, and neither is superior to ECMWF.
Quasi-periodic oscillations of aerosol backscatter profiles and surface meteorological parameters during winter nights over a tropical station
Authors: Manoj M. G. , Devara P. C. S.
Published: March 2011

Abstract. Atmospheric gravity waves, which are a manifestation of the fluctuations in buoyancy of the air parcels, are well known for their direct influence on concentration of atmospheric trace gases and aerosols, and also on oscillations of meteorological variables such as temperature, wind speed, visibility and so on. The present paper reports quasi-periodic oscillations in the lidar backscatter signal strength due to aerosol fluctuations in the nocturnal boundary layer, studied with a high space-time resolution polarimetric micro pulse lidar and concurrent meteorological parameters over a tropical station in India. The results of the spectral analysis of the data, archived on some typical clear-sky conditions during winter months of 2008 and 2009, exhibit a prominent periodicity of 20–40 min in lidar-observed aerosol variability and show close association with those observed in the near-surface temperature and wind at 5% statistical significance. Moreover, the lidar aerosol backscatter signal strength variations at different altitudes, which have been generated from the height-time series of the one-minute interval profiles at 2.4 m vertical resolution, indicate vertical propagation of these waves, exchanging energy between lower and higher height levels. Such oscillations are favoured by the stable atmospheric background condition and peculiar topography of the experimental site. Accurate representation of these buoyancy waves is essential in predicting the sporadic fluctuations of weather in the tropics.
Analysis of ionospheric electrodynamic parameters on mesoscales – a review of selected techniques using data from ground-based observation networks and satellites
Authors: Vanhamäki H. , Amm O.
Published: March 2011

Abstract. We present a review of selected data-analysis methods that are frequently applied in studies of ionospheric electrodynamics and magnetosphere-ionosphere coupling using ground-based and space-based data sets. Our focus is on methods that are data driven (not simulations or statistical models) and can be used in mesoscale studies, where the analysis area is typically some hundreds or thousands of km across. The selection of reviewed methods is such that most combinations of measured input data (electric field, conductances, magnetic field and currents) that occur in practical applications are covered. The techniques are used to solve the unmeasured parameters from Ohm's law and Maxwell's equations, possibly with help of some simplifying assumptions. In addition to reviewing existing data-analysis methods, we also briefly discuss possible extensions that may be used for upcoming data sets.
Contribution of riverine nutrients to the silicon biogeochemistry of the global ocean – a model study
Authors: Bernard C. Y. , Dürr H. H. , Heinze C. , Segschneider J. , Maier-Reimer E.
Published: March 2011

Abstract. Continental shelf seas are known to support a large fraction of the global primary production. Yet, they are mostly ignored or neglected in global biogeochemical models. A number of processes that control the transfer of dissolved nutrients from rivers to the open ocean remain poorly understood. This applies in particular to dissolved silica which drives the growth of diatoms that form a large part of the phytoplankton biomass and are thus an important contributor to export production of carbon. Here, the representation of the biogeochemical cycling along continents is improved by coupling a high resolution database of riverine fluxes of nutrients to the global biogeochemical ocean general circulation model HAMOCC5-OM. Focusing on silicon (Si), but including the whole suite of nutrients – carbon (C), nitrogen (N) and phosphorus (P) in various forms – inputs are implemented in the model at coastal coupling points using the COSCAT global database of 156 mega-river-ensemble catchments from Meybeck et al. (2006). The catchments connect to the ocean through coastal segments according to three sets of criteria: natural limits, continental shelf topography, and geophysical dynamics. According to the model the largest effects on nutrient concentrations occur in hot spots such as the Amazon plume, the Arctic – with high nutrient inputs in relation to its total volume, and areas that encounter the largest increase in human activity, e.g., Southern Asia.
Experimental fossilisation of viruses from extremophilic Archaea
Authors: Orange F. , Chabin A. , Gorlas A. , Lucas-Staat S. , Geslin C. , Le Romancer M. , Prangishvili D. , Forterre P. , Westall F.
Published: March 2011

Abstract. The role of viruses at different stages of the origin of life has recently been reconsidered. It appears that viruses may have accompanied the earliest forms of life, allowing the transition from an RNA to a DNA world and possibly being involved in the shaping of tree of life in the three domains that we know presently. In addition, a large variety of viruses has been recently identified in extreme environments, hosted by extremophilic microorganisms, in ecosystems considered as analogues to those of the early Earth. The earliest traces of life were preserved by the precipitation of silica on organic structures. The study of the in situ and experimental fossilisation of microorganisms allows better understanding of the fossilisation processes and helps identification of traces of life in ancient rocks. In a continuation of these studies, we present the results of the first experimental fossilisation by silica of viruses from extremophilic Archaea (SIRV2 – Sulfolobus islandicus Virus 2, TPV1 – Thermococcus prieurii virus 1, and PAV1 – Pyrococcus abyssi virus 1). Our results confirm that viruses can be fossilised, with silica precipitating on the different viral structures (proteins, envelope) over several months. However differences in the silicification process were noticed, depending on the viral structure and composition. The fossilisation mechanism is similar to that of the fossilisation of microorganisms. This study thus suggests that viral remains or traces could be preserved in the rock record although their identification may be challenging due to the small size of the viral particles.
Clouds and the Faint Young Sun Paradox
Authors: Goldblatt C. , Zahnle K. J.
Published: March 2011

Abstract. We investigate the role which clouds could play in resolving the Faint Young Sun Paradox (FYSP). Lower solar luminosity in the past means that less energy was absorbed on Earth (a forcing of −50 W m−2 during the late Archean), but geological evidence points to the Earth having been at least as warm as it is today, with only very occasional glaciations. We perform radiative calculations on a single global mean atmospheric column. We select a nominal set of three layered, randomly overlapping clouds, which are both consistent with observed cloud climatologies and reproduced the observed global mean energy budget of Earth. By varying the fraction, thickness, height and particle size of these clouds we conduct a wide exploration of how changed clouds could affect climate, thus constraining how clouds could contribute to resolving the FYSP. Low clouds reflect sunlight but have little greenhouse effect. Removing them entirely gives a forcing of +25 W m−2 whilst more modest reduction in their efficacy gives a forcing of +10 to +15 W m−2. For high clouds, the greenhouse effect dominates. It is possible to generate +50 W m−2 forcing from enhancing these, but this requires making them 3.5 times thicker and 14 K colder than the standard high cloud in our nominal set and expanding their coverage to 100% of the sky. Such changes are not credible. More plausible changes would generate no more than +15 W m−2 forcing. Thus neither fewer low clouds nor more high clouds can provide enough forcing to resolve the FYSP. Decreased surface albedo can contribute no more than +5 W m−2 forcing. Some models which have been applied to the FYSP do not include clouds at all. These overestimate the forcing due to increased CO2 by 20 to 25% when pCO2 is 0.01 to 0.1 bar.
Sub-daily variability of suspended sediment fluxes in small mountainous catchments &ndash implications for community-based river monitoring
Authors: Duvert C. , Gratiot N. , Némery J. , Burgos A. , Navratil O.
Published: March 2011

Abstract. Accurate estimates of suspended sediment yields depend on effective monitoring strategies. In mountainous environments undergoing intense seasonal precipitation, the implementation of such monitoring programs relies primarily on a rigorous study of the temporal variability of fine sediment transport. This investigation focuses on seasonal and short-term variability in suspended sediment flux in a subhumid region of the Mexican Volcanic Belt. Intensive monitoring was conducted during one year in four contrasting catchments (3 to 630 km2). Analyses revealed significant temporal variability in suspended sediment export over various time scales, with between 63 and 97% of the annual load exported in as little as 2% of the time. Statistical techniques were used to evaluate the sampling frequency required to get reliable estimates of annual sediment yield at the four sites. A bi-daily sampling scheme would be required at the outlet of the 630 km2 catchment, whereas in the three smaller catchments (3–12 km2), accurate estimates would inevitably require hourly monitoring. At the larger catchment scale, analysis of the sub-daily variability of fine sediment fluxes showed that the frequency of sampling could be lowered by up to 100% (i.e. from bi-daily to daily) if a specific and regular sampling time in the day was considered. In contrast, conducting a similar sampling strategy at the three smaller catchments could lead to serious misinterpretation (i.e. up to 1000% error). Our findings emphasise the importance of an analysis of the sub-daily variability of sediment fluxes in mountainous catchments. Characterising this variability may offer useful insights for improving the effectiveness of community-based monitoring strategies in rural areas of developing countries. In regions where historical records based on discrete sampling are available, it may also help assessing the quality of past flux estimates. Finally, the study confirms the global necessity of acquiring more high frequency data in small mountainous catchments, especially in poorly gauged areas.
Köppen versus the computer: an objective comparison between the Köppen-Geiger climate classification and a multivariate regression tree
Authors: Cannon A. J.
Published: March 2011

Abstract. A global climate classification is defined using a multivariate regression tree (MRT). The MRT algorithm is automated, which removes the need for a practitioner to manually define the classes; it is hierarchical, which allows a series of nested classes to be defined; and it is rule-based, which allows climate classes to be unambiguously defined and easily interpreted. Climate variables used in the MRT are restricted to those from the Köppen-Geiger climate classification. The result is a hierarchical, rule-based climate classification that can be directly compared against the traditional system. An objective comparison between the two climate classifications at their 5, 13, and 30 class hierarchical levels indicates that both perform well in terms of identifying regions of homogeneous temperature variability, although the MRT still generally outperforms the Köppen-Geiger system. In terms of precipitation discrimination, the Köppen-Geiger classification performs poorly relative to the MRT. The data and algorithm implementation used in this study are freely available. Thus, the MRT climate classification offers instructors and students in the geosciences a simple instrument for exploring modern, computer-based climatological methods.
Anthropic Rock: a brief history
Authors: Cathcart R. B.
Published: March 2011

Abstract. Stone tool-making is a reductive process. Synthetic rock manufacturing, preeminently an additive process, will not for-ever be confined to only the Earth-biosphere. This brief focuses on humanity's ancient past, hodiernal and possible future even more massive than present-day creation of artificial rocks within our exploitable Solar System. It is mostly Earth-centric account that expands the factual generalities underlying the unique non-copyrighted systemic technogenic rock classification first publicly presented (to the American Geological Society) during 2001, by its sole intellectual innovator, James Ross Underwood, Jr. His pioneering, unique exposition of an organization of this ever-increasingly important aspect of the Anthropic Rock story, spatially expansive material lithification, here is given an amplified discussion for the broader geo and space science social group-purpose of encouragement of a completer 21st Century treatment of Underwood's explicative subject-chart (Fig. 2).
Synthesis of Biodegradable Amphiphilic Nanocarriers by Chemo-Enzymatic Transformations for the Solubilization of Hydrophobic Compounds
Authors: Kumar Sumit , Mohr Andreas , Kumar Amit , Sharma Sunil K. , Haag Rainer
Published: March 2011

Polymeric nanocarriers possess advanced physicochemical properties that improve bioavailability, enhance cellular dynamics, and control target ability in drug delivery. In particular, dendritic polyglycerol is a promising new biocompatible scaffold for drug delivery. The present study explores the chemo-enzymatic modifications on dendritic hyperbranched polyglycerol (dPG) leading to amphiphilic polymeric architectures with easily hydrolysable ester linkages. Furthermore, these architectures were studied for nile red solubilization with capacity up to 5.6 mg/L at 0.1 wt % polymer conc. This corresponds to an ~10 fold increase in solubility of nile red. The release of nile red from these polymers was observed with a half life of 8 hours at pH 5.0, while no release was found at pH 7.4. The cell viability studies of our polymeric architectures showed them to be relatively nontoxic and to have the potential for future drug delivery applications.
One-Way and Reversible Dual-Shape Effect of Polymer Networks Based on Polypentadecalactone Segments
Authors: Behl Marc , Zotzmann Jörg , Lendlein Andreas
Published: March 2011

A series of degradable polymer networks containing poly(ω-pentadecalactone) (PPD) switching segments showing a thermally-induced shape-memory effect were synthesized by co-condensation of PPD-macrotriols or -tetrols with an aliphatic diisocyanate. Thermal and mechanical properties at different temperatures were explored for polymer networks as a function of crosslink density by varying the polymer chain segment length or the netpoint functionality. All polymer networks exhibited excellent shape-memory properties with shape recovery rates Rr between 99% and 100% determined in the 5th cycle under stress-free conditions. Furthermore, the polymer networks were capable of a reversible dual-shape effect based on crystallization induced elongation (CIE) and melting-induced contraction (MIC) in cyclic, thermomechanical experiments under constant stress. In these tests, the polymer networks were capable of a shape-change of 130% elongation. The associated temperatures at which CIE or MIC occurred (TCIE and TMIC) were shown to be a function of the applied stress. By an increase of stress of 1.6 MPa, TCIE could be increased by 10 K.
El as the Speaking Voice in Psalm 82:6–8
Authors: Frankel David
Published: March 2011

YHWH is usually understood to play two roles in Psalm 82: that of prosecutor of the gods (vv 2–5) and that of high judge who convicts the gods to death (vv 6–7). This article suggests that the role of the high judge is played not by YHWH but by El. YHWH serves as prosecutor of the gods in El's court. In this reading YHWH speaks only in vv 2–5. In vv 6–8 El offers his verdict, after hearing the testimony of YHWH against the gods. After sentencing the gods of his council to death (vv 6–7), El appoints YHWH to rule the world in their place (v 8).
Archaeology and Professional Ethical Codes in Israel in the mid 80s: The Case of the Association of Archaeologists in Israel and Its Code of Ethics
Authors: Kletter Raz , Solimani Gideon
Published: March 2011

This article deals with the (relatively) short-lived Association of Archaeologists in Israel and its Code of Ethics. By doing so, it sheds light on an episode in the history of Israeli archaeology that has not received much attention in research.
In Conversation With Joshua A. Berman, Created Equal: How the Bible Broke With Ancient Political Thought (Oxford University Press, 2008).
Authors: Olyan Saul M. , Berman Joshua A. , Ackerman Susan , Gottwald Norman
Published: March 2011

This contribution emerges out of a session devoted to a critical assessment of the book that took place at the 2009 SBL Annual Meeting. It includes Joshua Berman, “Created Equal: Main Claims and Methodological Assumptions,” Susan Ackerman, “Only Men are Created Equal, ”Norman Gottwald, “Between Diachronic and Synchronic Approaches,” Saul M. Olyan, “Equality and Inequality in the Socio-Political Visions of the Pentateuch’s Sources,” and Joshua Berman, “A Response: Three Points of Methodology”
Cationic Gold(I)‐Catalyzed Intermolecular [4+2] Cycloaddition between Dienes and Allenyl Ethers
Authors: Wang Guan , Zou Yue , Li Zhiming , Wang Quanrui , Goeke Andreas
Published: March 2011

Simple allenyl ethers have been shown to be efficiently activated by cationic gold(I) catalysts to form reactive dienophiles in intermolecular Diels–Alder reactions. A range of different dienes give the cycloaddition products in moderate to excellent yields and good selectivity.
Efficient Synthesis of 9‐Tosylaminofluorene Derivatives by Boron Trifluoride Etherate‐Catalyzed Aza‐Friedel–Crafts Reaction of in situ Generated N‐Tosylbenzaldimines
Authors: Yu Xufen , Lu Xiyan
Published: March 2011

An efficient and expeditious boron trifluoride etherate (BF3⋅Et2O) catalyzed one‐pot reaction for the synthesis of N‐tosyl‐9‐aminofluorenes and anthracene derivatives from in situ generated N‐tosylbenzaldimines via an aza‐Friedal–Crafts reaction has been developed. The catalytic reaction shows high substrate tolerance with excellent yields.
Oxaphosphole‐Based Monophosphorus Ligands for Palladium‐Catalyzed Amination Reactions
Authors: Rodriguez Sonia , Qu Bo , Haddad Nizar , Reeves Diana C. , Tang Wenjun , Lee Heewon , Krishnamurthy Dhileepkumar , Senanayake Chris H.
Published: March 2011

A novel class of C‐2‐substituted oxaphosphole‐based monophosphines 1–4 has been synthesized. Palladium complexes derived from these ligands and their C‐2‐unsubstituted analogs provide general catalysts for amination reactions of challenging aryl and heteroaryl halides with sterically hindered anilines and alkylamines.
Removal of pyridine from water by pervaporation using filled SBR Membranes
Authors: Singha N. R. , Ray S. , Ray S. K. , Konar B. B.
Published: March 2011

Styrene butadiene rubber (SBR) was efficiently cured (crosslinked) by using sulfur to accelerator ratio less than unity. This cured SBR was further compounded with carbon black filler (grade N330) with three different doses i.e., 5, 10, and 20 wt % of filler to form three different filled and crosslinked membranes, i.e., SBR5, SBR10, and SBR20. These filled rubber membranes and one unfilled but efficiently cured membrane, i.e. SBR0, were used for pervaporative removal of pyridine from its mixtures with water. The filled membranes were found to show better selectivity and mechanical properties but lower flux than the unfilled membrane. All of these membranes showed reasonably good range of flux and pyridine selectivity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Improved adhesion of silicone rubber to polyurethane by surface grafting
Authors: Wang Jing , Xia Weijuan , Liu Kun , Tuo Xinlin
Published: March 2011

Polyurethane (PU) has widespread applications in implantable devices because of its excellent mechanical and biocompatible properties, whereas weak biostability limits its long‐term implantation. The introduction of silicone rubber (SR) onto the PU surface is an effective method for improving the biostability of PU, but the adhesion of these two polymers is unsatisfactory. In this study, the surface modification of PU via grafting through the introduction of vinyl and SiH groups onto the PU surface was attempted to improve the adhesion of PU to SR. Fourier transform infrared, energy‐dispersive X‐ray spectroscopy, and X‐ray photoelectron spectroscopy were employed to investigate the graft reaction on the PU surface. The interfacial and surface morphology was characterized with scanning electron microscopy. Different PU/SR interfaces after oscillation and shear were compared as well. The results indicated that the PU surface was activated by diisocyanate, which generated free isocyanate groups for the further grafting of vinyl and SiH groups. When addition‐type, room‐temperature‐vulcanized SR was poured onto the PU surface, the vinyl and SiH groups on the PU surface underwent an addition reaction, which improved the adhesion of PU and SR by connecting them with chemical bonds. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Grafting of polyacrylamide from poly(ethylene terephthalate) films
Authors: Zhou Chao , Zhang Hong‐Wen , Jiang Yan , Wang Wen‐Jun , Yu Qiang
Published: March 2011

Poly(ethylene terephthalate) (PET) films were modified via the grafting of polyacrylamide (PAAM) onto the surface by surface‐initiated atom transfer radical polymerization and UV‐initiated grafting. The surface composition and morphology of the modified PET films were characterized by Fourier transform infrared spectroscopy, X‐ray photoelectron spectroscopy, and scanning electron microscopy (SEM). The results show that the surface of the PET film was grafted by PAAM, with its own surface morphology different from that of PET. The properties of the modified PET films were studied by contact‐angle, peeling force, penetrability, haze, and friction factor measurements. The results indicate that the peeling force and friction factor of the modified PET films were higher than those of the unmodified PET film. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Polymerization kinetics of acrylonitrile by oxidation: Reduction system using potassium persulfate/ascorbic acid in an aqueous medium
Authors: Nagaraja G. K. , Demappa T. , Mahadevaiah
Published: March 2011

The kinetics of acrylonitrile polymerization initiated by free radicals formed in situ in a potassium persulfate/ascorbic acid redox system was investigated in an aqueous sulfuric acid medium in the temperature range of 40–70°C. The rate of polymerization and the rate of the disappearance of potassium persulfate were measured. A kinetic scheme involving the production of initiating radicals from the oxidation of ascorbic acid by potassium persulfate ions and termination exclusively by the interaction of chain radicals with persulfate ions is proposed. The effects of some water‐miscible organic solvents on the rate of polymerization were investigated. The temperature dependence of the rate was studied. A possible mechanism consistent with the experimental data is proposed. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
The dynamic crystallization and multiple melting behavior of polypropylene in the in‐reactor alloy: A differential scanning calorimetry study
Authors: Zhu Haijin , Yang Hengrui , Zhao Ying , Wang Dujin
Published: March 2011

The isothermal and nonisothermal crystallization and the subsequent melting behaviors of the polypropylene (PP) component in the in‐reactor alloy were studied systematically by a series of thermal analysis techniques. The alloy sample used in the present study is a newly invented in situ blend of polypropylene with high ethylene–propylene rubber content. The effect of annealing temperatures on the subsequent crystallization and melting process of PP was explained by the different molecular behavior in the three “temperature domains.” Multiple melting endotherms were also obser‐ved for the nonisothermally crystallized sample, and were attributed to the dynamic melting process which consists of three steps: melting, recrystallization, and remelting. The melting temperature of initial mesomorphic phase is found to be very close to the temperature of recrystallization or reorganization. To separate the recrystallization process from the overlapping processes, the difference spectra of fast and slow heated DSC endotherms were used, which is based on a straight forward but reasonable assumption. In addition, temperature modulated differential scanning calorimetry (TMDSC) has also been used to study the melting of PP component. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
New polysiloxane‐chemically immobilized C,C‐bipyrazolic receptor for heavy metals adsorption
Authors: Radi Smaail , Toubi Yahya , Attayibat Ahmed , Bacquet Maryse
Published: March 2011

A porous polysiloxane has been chemically modified with a functional C,C‐bibyrazolic ligand using the heterogeneous route. This synthetic route involved the reaction of 3‐glycidoxypropyltrimethoxysilane silylant agent, previously anchored on a silica surface, with C,C‐bipyrazolic ligand. The new modified polysiloxane (SiL) has been characterized by elemental analysis and infrared spectra and was studied and evaluated by determination of the surface area using the BET equation, the adsorption and desorption capability using the isotherm of nitrogen and B.J.H. Pore sizes. The new inorganic‐organic polymer exhibits good thermal stability determined by thermogravimetry curves and good chemical stability examined in various acidic and buffer solutions. The solid was utilized in batch method for separation and trace extraction of (Hg2+, Cd2+, Pb2+, and Cu2+) and compared with the results of classical liquid‐liquid extraction with the unbound C,C‐bipyrazole compound. The grafting at the surface of silica does not affect complexing properties of the ligand and the material exhibits a high selectivity toward Hg(II). © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Comparative study on the electrooptical properties of polymer‐dispersed liquid crystal films with different mixtures of monomers and liquid crystals
Authors: Ahmad Farzana , Jamil Muhammad , Jeon Young Jae , Woo Lee Jin , Jung Jae Eun , Jang Jae Eun , Lee Gae Hwang , Park Jinsang
Published: March 2011

This article deals with the study of polymer‐dispersed liquid crystal (PDLC) films that consisted of microdroplets of liquid crystals (LCs) dispersed in a polymer matrix. The PDLC films were fabricated by the photoinduced phase separation method under room‐temperature conditions. To determine the extent of the effects of the molecular structures and their physical properties of different mixtures of monomers and LCs on the morphology and electrooptical properties of the PDLC films, various mixtures were used. A detailed discussion of the obtained results is given. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Chemistry, functionality, and coating performance of biobased copolycarbonates from 1,4:3,6‐dianhydrohexitols
Authors: Noordover Bart A. J. , Haveman Daniël , Duchateau Robbert , van Benthem Rolf A. T. M. , Koning Cor E.
Published: March 2011

Biobased polycarbonates were synthesized from 1,4:3,6‐dianhydro‐D‐glucitol, 1,4:3,6‐dianhydro‐L‐iditol, and 1,4:3,6‐dianhydro‐D‐mannitol as the principal diols, using different types of carbonyl sources. The (co)polycarbonates resulting from polycondensation reactions in solution using triphosgene consisted of several types of polymer chains with respect to chain topology (e.g., linear or cyclic chains) and end‐group structure (e.g., hydroxyl, chloroformate or alkyl chloride end‐groups). The introduction of flexible comonomers seemed to increase the amount of cyclic structures in the product mixtures. The melt polymerization of diphenyl carbonate with 1,4:3,6‐dianhydrohexitols required high reaction temperatures and led to almost exclusively hydroxy‐functional poly(1,4:3,6‐dianhydrohexitol carbonate)s. Copolymerizing the 1,4:3,6‐dianhydrohexitols with 1,3‐propanediol and diphenyl carbonate at high temperature resulted in the partial loss of 1,3‐propanediol. On the other hand, by melt polycondensation of 1,4:3,6‐dianhydrohexitol‐based bis(phenyl carbonate) monomers in combination with primary diols and/or triols, the insertion of the primary alcohols could be achieved in a more controlled way. OH‐functional materials were prepared, having suitable molecular weights, Tg values, thermal stability, and melt viscosity profiles for (powder) coating applications. These functional biobased (co)polycarbonates were cured with polyisocyanate curing agents, resulting in colorless to pale yellow transparent, glossy coatings with good mechanical performance and solvent resistance. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Recyclable polyvinyl chloride‐supported pyrrolidine‐thiourea as a bifunctional organocatalyst for direct asymmetric aldol reaction in aqueous medium
Authors: Li Jia , Yang Gengxu , Cui Yuanchen
Published: March 2011

Novel polyvinyl chloride (PVC)‐supported pyrrolidine‐thiourea has been first synthesized in a simple route. The target product was used as a bifunctional organocatalyst for the direct asymmetric aldol reaction between cyclohexanone and arylaldehydes. Effects of solvent and catalyst loading on reaction have been explored. It was found that even at a small dosage of 2.5 mol %, the catalyst exhibited high catalytic activity and stereoselectivities at room temperature in aqueous medium. Additionally, the catalyst can be reused at least for three times. The PVC resin can provide hydrophobic microenvironment for the substrates and catalytic center (pyrrolidine and thiourea moiety) to contact closely. The aldol reaction may take place at the interface between the polymer and aqueous phase. And the results indicated that the thiourea moiety of catalyst had an important effect on the activity and selectivity of the aldol reaction. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and characterization of 4A zeolite‐filled mixed matrix membranes for pervaporation dehydration of isopropyl alcohol
Authors: Prasad C. Venkata , Swamy B. Yerri , Sudhakar H. , Sobharani T. , Sudhakar K. , Subha M. C. S. , Rao K. Chowdoji
Published: March 2011

Sodium carboxymethylcellulose/poly (vinyl alcohol) mixed matrix membranes filled with different amounts 4A zeolite (0, 5, 10, 15, and 20 wt %) were prepared by solution casting method. Prepared membranes were crosslinked with GA and used for pervaporation dehydration of isopropyl alcohol of different feed mixtures at 35°C. On increment in zeolite content in the membrane it was found the improvement in the performance of the membrane, due to its hydrophilic nature and molecular sieving effect in addition to its favorable interaction with hydrophilic sodium carboxymethylcellulose and polyvinyl alcohol. The structure and chemical constituents of the MMM's were investigated by attenuated total reflectance Fourier transform infrared spectroscopy. Thermal stability of the membranes was assessed by DSC and TGA techniques. Crystallinity of the membranes was assessed using X‐ray diffraction, and the morphological properties were assessed by scanning electron microscopy. Mechanical properties were also carried out to determine the tensile strength and % of elongation at break using universal testing machine. It was found that the mechanical strength increases with increase in the zeolite content upto 15 wt % of zeolite with an optimum tensile strength of 113.31 N/mm2. Pervaporation was carried out to asses the membrane performance, the highest flux and selectivity obtained is 0.584 kg/m2/h and 6945 for NaCMCA20 and NaCMCA15, respectively, for a feed composition containing 17.5 and 10 wt % of water in the feed and further swelling studies also supporting the pervaporation results. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Inhibition of mild steel corrosion in acidic medium using starch and surfactants additives
Authors: Mobin M. , Khan M. A. , Parveen M.
Published: March 2011

The corrosion inhibition of mild steel in 0.1M H2SO4 in presence of starch (polysaccharide) was studied using weight loss and potentiodynamic polarization measurements in the temperature range of 30–60°C. Starch inhibits the corrosion rates of mild steel to a considerable extent; the maximum inhibition efficiency (%IE) being 66.21% at 30oC in presence of starch concentration of 200 ppm. The effect of the addition of very small concentration of sodium dodecyl sulfate and cetyl trimethyl ammonium bromide on the corrosion inhibition behavior of starch was also studied. The IE of starch significantly improved in presence of both the surfactants. The effect of surfactants on the corrosion inhibition behavior of starch appears to be synergistic in nature. Starch alone and in combination with surfactants is found to obey Langmuir adsorption isotherm from the fit of the experimental data of all concentration and temperature studied. Phenomenon of physical adsorption is proposed from the trend of IE with temperature and also the values Ea, ΔGads, and Qads obtained. The results obtained by potentiodynamic polarization measurements are consistent with the results of the weight loss measurement. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Preparation and characterization of a microporous polymer electrolyte based on poly(vinylidene fluoride)/ionic‐liquid‐functionalized SiO2 for dye‐sensitized solar cells
Authors: Yan Yang , Jie Tao , Xin Jin , Qi Qin
Published: March 2011

A new type of ionic‐liquid‐functionalized SiO2 (IL‐SiO2) was synthesized to develop a microporous polymer electrolyte for quasi‐solid‐state dye‐sensitized solar cells. The samples were characterized by 1H‐NMR, Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, and X‐ray diffraction. Moreover, the ionic conductivity of the electrolytes was measured by an electrochemical workstation. Nanostructured silica containing imidazolium iodide showed excellent compatibility with the organic solvent. The incorporation of the IL‐SiO2 component into the polymer matrix improved the electrochemical behavior of the gel polymer electrolyte. A dye‐sensitized solar cell with a gel polymer electrolyte yielded an open‐circuit voltage of 0.662 V, a short‐circuit current of 13.40 mA/cm2, and a conversion efficiency of 4.01% at 1 sun illumination. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Pleuroperitoneal Canal Closure and the Fetal Adrenal Gland
Authors: Hayashi Shogo , Fukuzawa Yoshitaka , Rodríguez‐Vázquez José Francisco , Cho Baik Hwan , Verdugo‐López Samuel , Murakami Gen , Nakano Takashi
Published: March 2011

Pleuroperitoneal canal (PP canal) closure is generally considered to result from an increase in the height, and subsequent fusion, of the bilateral pleuroperitoneal folds (PP folds). However, the folds develop in the area ventral to the adrenal, in contrast to the final position of the diaphragm, which extends to the dorsal side of the adrenal (the “retro‐adrenal” diaphragm). We examined the semiserial histology of 20 human embryos and fetuses (crown‐rump length 11–40 mm). We started observations of the canal at the stage through which the lung bud extends far caudally along the dorsal body wall to the level of the future adrenal, and the phrenic nerve has already reached the PP fold. Subsequently, the developing adrenal causes narrowing of the dorsocaudal parts of the canal, and provides the bilateral midsagittal recesses or “false” bottoms of the pleural cavity. However, at this stage, the PP fold mesenchymal cells are still restricted to the ventral side of the adrenal, especially along the liver and esophagus. Thereafter, in accordance with ascent of the lung, possibly due to anchoring of the liver to the adrenal, the PP fold mesenchymal cells seem to migrate laterally along the coelomic mesothelium covering some sheet‐like loose mesenchymal tissue behind the adrenal. Final closure of the PP canal by lateral migration to provide the “retro‐adrenal” diaphragm is a process quite different from the common dogma. It is likely that the sheet‐like loose mesenchymal tissue becomes the caudal part of the pleural cavity through a process involving cell death. Anat Rec, 2011. © 2011 Wiley‐Liss, Inc.
Electrophysiological response patterns of 16 olfactory neurons from the trichoid sensilla to odorant from fecal volatiles in the locust, locusta migratoria manilensis
Authors: Cui Xiaojie , Wu Caihong , Zhang Long
Published: March 2011

Locusts are the most serious pests of crops in greater part of the world. They locate their host plants primarily through olfactory cues, using antennal chemosensilla, which house olfactory receptor neurons (ORNs). Despite the great economical interest of these species, their olfactory neurons have been poorly investigated at the functional level. In this study, we have used single sensillum recordings (SSRs) to obtain response patterns of ORNs from the antennal trichoid sensilla to various chemicals in the oriental locust Locusta migratoria. On the basis of their spontaneous spike amplitudes, trichoid sensilla could be distinguished into two types, housing two or three ORNs, respectively. These two structural types could be further classified into seven functional subtypes. Nine different odorants that are present in the locust feces were used as stimulants during SSRs. In particular, benzaldehyde elicited inhibitory responses in most of the ORNs tested. Moreover, in a majority of these ORNs, the excitatory responses obtained with trans‐2‐hexenal or 2‐heptanone was inhibited when benzaldehyde was mixed with these stimulants. At least 16 response patterns of these ORNs to nine chemicals were identified by SSRs, suggesting a high complexity of the cellular mechanisms underlying chemoreception in locusts. © 2011 Wiley Periodicals, Inc.
Global finite‐time stabilization of planar nonlinear systems with disturbance
Authors: Li Peng , Zheng Zhiqiang
Published: March 2011

This paper proposes a continuous global finite‐time controller for a class of planar systems with disturbance. The proposed controller consists of nominal and compensated parts. The nominal part, designed by an homogeneity‐based technique, takes care only of the nominal system. The closed‐loop nominal system is asymptotically stable and satisfies negative homogeneity of degree. However, using a finite‐time convergent second order sliding mode super‐twisting algorithm, the compensated part enables cancelling of the disturbance which is time‐varying or unbounded as long as its derivative is bounded. The combination of the nominal and compensated parts makes the planar system globally finite‐time stable. Simulation results show the effectiveness of the proposed method.

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