bluuebunny/crossref_metadata_2025 huggingface dataset:
A soil moisture and temperature network for SMOS validation in Western Denmark
Authors: Bircher S. , Skou N. , Jensen K. H. , Walker J. P. , Rasmussen L.
Published: May 2012

Abstract. The Soil Moisture and Ocean Salinity Mission (SMOS) acquires surface soil moisture data of global coverage every three days. Product validation for a range of climate and environmental conditions across continents is a crucial step. For this purpose, a soil moisture and soil temperature sensor network was established in the Skjern River Catchment, Denmark. The objectives of this article are to describe a method to implement a network suited for SMOS validation, and to present sample data collected by the network to verify the approach. The design phase included (1) selection of a single SMOS pixel (44 × 44 km), which is representative of the land surface conditions of the catchment and with minimal impact from open water (2) arrangement of three network clusters along the precipitation gradient, and (3) distribution of the stations according to respective fractions of classes representing the prevailing environmental conditions. Overall, measured moisture and temperature patterns could be related to the respective land cover and soil conditions. Texture-dependency of the 0–5 cm soil moisture measurements was demonstrated. Regional differences in 0–5 cm soil moisture, temperature and precipitation between the north-east and south-west were found to be small. A first comparison between the 0–5 cm network averages and the SMOS soil moisture (level 2) product is in range with worldwide validation results, showing comparable trends for SMOS retrieved soil moisture (R2 of 0.49) as well as initial soil moisture and temperature from ECMWF used in the retrieval algorithm (R2 of 0.67 and 0.97, respectively). While retrieved/initial SMOS soil moisture indicate significant under-/overestimation of the network data (biases of −0.092/0.057 m3 m−3), the initial temperature is in good agreement (bias of −0.2 °C). Based on these findings, the network performs according to expectations and proves to be well-suited for its purpose. The discrepancies between network and SMOS soil moisture will be subject of subsequent studies.
Behavior analysis of convective and stratiform rain using Markovian approach over Mediterranean region from meteorological radar data
Authors: Lazri M. , Hameg S. , Ameur S. , Brucker J. M. , Ouallouche F. , Mohia Y.
Published: May 2012

Abstract. The aim of this study is to analyze the chronological behavior of precipitation in the north of Algeria using a Markovian approach. The probabilistic approach presented here proposes to study the evolution of the rainfall phenomenon in two distinct study areas, one located in sea and other located in ground. The data that we have used are provided by the National Office of Meteorology in Algiers (ONM). They are a series of images collected by the meterological radar of Setif during the rainy season 2001/2002. A decision criterion is established and based on radar reflectivity in order to classify the precipitation events located in both areas. At each radar observation, a state of precipitations is classified, either convective (heavy precipitation) or stratiform (average precipitation) both for the "sea" and for the "ground". On the whole, a time series of precipitations composed of three states; S0 (no raining), S1 (stratiform precipitation) and S2 (convective precipitation), is obtained for each of the two areas. Thereby, we studied and characterized the behavior of precipitation in time by a Markov chain of order one with three states. Transition probabilities Pij of state Si to state Sj are calculated. The results show that rainfall is well described by a Markov chain of order one with three states. Indeed, the stationary probabilities, which are calculated by using the Markovian model, and the actual probabilities are almost identical.
Trends in rainfall erosivity in NE Spain at annual, seasonal and daily scales, 1955–2006
Authors: Angulo-Martínez M. , Beguería S.
Published: May 2012

Abstract. Rainsplash – the detachment and transport of soil particles by the impact of raindrops on a bare soil – is a major mechanism of soil degradation and erosion on semiarid areas and agricultural lands. Rainfall erosivity refers to the ability of precipitation to erode soil, and depends on the characteristics of the raindrops – size and velocity – and on the rainfall intensity and duration. Despite the relevance of rainfall erosivity for soil degradation prevention very few studies addressed its spatial and temporal variability. On this study the time variation of rainfall erosivity in the Ebro valley (NE Spain) is assessed for the period 1955–2006. The results show a general decrease in annual and seasonal rainfall erosivity, which is explained by a decrease of very intense rainfall events whilst the frequency of moderate and low events increased. This trend is related to prevailing positive conditions of the main atmospheric teleconnection indices affecting the West Mediterranean, i.e. the North Atlantic Oscillation (NAO), the Mediterranean Oscillation (MO) and the Western Mediterranean Oscillation (WeMO).
Iceland spar and its legacy in science
Authors: Kristjánsson L.
Published: May 2012

Abstract. In the late 17th century, Rasmus Bartholin and Christiaan Huygens investigated a curious optical property of crystals found at Helgustaðir in Eastern Iceland. This property which has been called double refraction, revealed in the 19th century a new aspect of light which turned out to be very useful as a probe of the internal structure of matter. Clear specimens of these crystals, an unusually pure variety of calcite, have since around 1780 been known as ''Iceland spar''. Few if any other localities yielding calcite crystals of comparable size and quality were discovered before 1900, and no alternatives for use in precision optical instrumentation were developed until the 1930s. Hundreds of tons of calcite were exported from Helgustaðir, mostly between 1850 and 1925. However, little information has been found on trading routes for the material of optical quality, so that some enigmas remain regarding its supply-demand situation. A study of the scientific literature in the period up to 1930 has revealed that results obtained with the aid of Iceland spar accelerated progress within the earth sciences (in mineralogy and petrology), physics, chemistry, and biology, even by decades. This has also influenced the development of technology and of medicine in various direct and indirect ways.
Comparable analysis of the distribution functions of runup heights of the 1896, 1933 and 2011 Japanese Tsunamis in the Sanriku area
Authors: Choi B. H. , Min B. I. , Pelinovsky E. , Tsuji Y. , Kim K. O.
Published: May 2012

Abstract. Data from a field survey of the 2011 Tohoku-oki tsunami in the Sanriku area of Japan is used to plot the distribution function of runup heights along the coast. It is shown that the distribution function can be approximated by a theoretical log-normal curve. The characteristics of the distribution functions of the 2011 event are compared with data from two previous catastrophic tsunamis (1896 and 1933) that occurred in almost the same region. The number of observations during the last tsunami is very large, which provides an opportunity to revise the conception of the distribution of tsunami wave heights and the relationship between statistical characteristics and the number of observed runup heights suggested by Kajiura (1983) based on a small amount of data on previous tsunamis. The distribution function of the 2011 event demonstrates the sensitivity to the number of measurements (many of them cannot be considered independent measurements) and can be used to determine the characteristic scale of the coast, which corresponds to the statistical independence of observed wave heights.
Impact of Preoperative Therapy with 5-α-Reductase Inhibitors in the Treatment of Benign Prostatic Hyperplasia
Authors: De Stefano Giacomo , Fusco Ferdinando , Arcaniolo Davide , Pistone Antonio , Capece Marco , Mirone Simone Sannino Vincenzo
Published: May 2012

Benign prostatic hyperplasia is considered a progressive disease intimately linked with aging. The long-term use of combination therapy with a 5-alpha-reductase inhibitor, together with an alpha blocker in men with moderate-severe symptoms, reduces the risk of clinical progression and BPH-related surgery.

It is unclear what the impact is of preoperative therapy with 5-ARI in patients that undergo surgery. The aim of our study was to evaluate the impact of preoperative therapy with 5-alpha-reductase inhibitors on: a) indication on the type of surgery; b) surgical and functional outcomes; c) surgical complications. This is a prospective observational study. It will include all patients undergoing surgery by TURP or Open Prostatectomy in a period of 24 months.

We expect results that demonstrate significant and favorable influence of pretreatment with 5-alpha-reductase inhibitors on certain outcomes. Therefore, therapy with 5-ARI could be considered as neoadjuvant to surgery, whatever this is.
Oil and the U.S. Macroeconomy: A Reinvestigation Using Rolling Impulse Responses
Authors: Gronwald Marc
Published: May 2012

This paper investigates the role of extreme oil price increases in empirical studies of the macroeconomics of oil prices. The innovative approach of rolling impulse responses is applied and data on both the aggregate and the industry-level is considered. The results show that the first oil crisis drives long-run results and superimposes both subsample and industry-specifics. Furthermore, there is evidence that the non-occurrence of large oil shocks after the mid-1980s is an important explanation for the Great Moderation.
Providing Free Autopoweroff Plugs: Measuring the Effect on Households’ Electricity Consumption through a Field Experiment
Authors: Jensenf Carsten Lynge , Hansen Lars Gårn , Fjordbak Troels , Gudbjerg Erik
Published: May 2012

Experimental evidence of the effect of providing households with cheap energy saving technology is sparse. We present results from a field experiment in which autopoweroff plugs were provided free of charge to randomly selected households. We use propensity score matching to find treatment effects on metered electricity consumption for different types of households. We find effects for single men and couples without children, while we find no effect for single women and households with children. We suggest that this could be because of differences in saving potential (e.g. some households do not have appliances where using a plug is relevant), differences in the skills relevant for installing the technology and differences in the willingness to spend time and effort on installation. We conclude that targeting interventions at more responsive households, and tailoring interventions to target groups, can increase the efficiency of programs.
From Bioconjugation to Self‐Assembly in Nanobiotechnology: Quantum Dots Trapped and Stabilized by Toroid Protein Yoctowells
Authors: Schreiber Andreas , Yuan Ying , Huber Matthias C. , Thomann Ralf , Ziegler Andreas , Cölfen Helmut , Dengjel Jörn , Krüger Michael , Schiller Stefan M.
Published: May 2012

Conjugation of quantum dots (QDs) with proteins is applicable for biosensing and imaging in biomedical applications but also for the confined assembly of various nanostructures. Here, the conjugation of CdSe QDs ranging from 2.5 up to 9.5 nm with Hcp1, a yoctowell forming hexameric core protein of Pseudomonas aeruginosa, is described. Defined structures ranging from single QDs trapped within the donut‐shaped hexameric protein cavity over “globular” multi‐toroid architectures up to photonic wires of 850 nm in length and 9 nm in width are self‐assembled while preserving the native hexameric structure of the protein conserving the photoluminescence intensity of the QDs in aqueous solution for more than 3 month.
Chemoenzymatic Synthesis of GDP‐L‐Fucose Derivatives as Potent and Selective α‐1,3‐Fucosyltransferase Inhibitors
Authors: Lin Yu‐Nong , Stein Daniel , Lin Sheng‐Wei , Chang Sue‐Ming , Lin Ting‐Chien , Chuang Yu‐Ruei , Gervay‐Hague Jacquelyn , Narimatsu Hisashi , Lin Chun‐Hung
Published: May 2012

Fucosyltransferases (FucTs) usually catalyze the final step of glycosylation and are critical to many biological processes. High levels of specific FucT activities are often associated with various cancers. Here we report the development of a chemoenzymatic method for synthesizing a library of guanosine diphosphate β‐L‐fucose (GDP‐Fuc) derivatives, followed by in situ screening for inhibitory activity against bacterial and human α‐1,3‐FucTs. Several compounds incorporating appropriate hydrophobic moieties were identified from the initial screening. These were individually synthesized, purified and characterized in detail for their inhibition kinetics. Compound 5 had a Ki of 29 nM for human FucT‐VI, and is 269 and 11 times more selective than for Helicobacter pylori FucT (Ki=7.8 μM) and for human FucT‐V (Ki=0.31 μM).
Fifteen years of occupational and environmental health projects support in Brazil, Chile, and Mexico: A report from Mount Sinai School of Medicine ITREOH program, 1995–2010
Authors: Peres Frederico , Claudio Luz
Published: May 2012

Background

The Fogarty International Center of the National Institutes of Health created the International Training and Research Program in Occupational and Environmental Health (ITREOH program) in 1995 with the aim to train environmental and occupational health scientists in developing countries. Mount Sinai School of Medicine was a grantee of this program since its inception, partnering with research institutions in Brazil, Chile, and Mexico. This article evaluates Mount Sinai's program in order to determine whether it has contributed to the specific research capacity needs of the international partners.

Methods

Information was obtained from: (a) international and regional scientific literature databases; (b) databases from the three participating countries; and (c) MSSM ITREOH Program Database.

Results

Most of the research projects supported by the program were consistent with the themes found to be top priorities for the partner countries based on mortality/morbidity and research themes in the literature. Indirect effects of the training and the subsequent research projects completed by the trained fellows in the program included health policy changes and development of collaborative international projects.

Conclusion

International research training programs, such as the MSSM ITREOH, that strengthen scientific research capacity in occupational and environmental health in Latin America can make a significant impact on the most pressing health issues in the partner countries. Am. J. Ind. Med. 56:29–37, 2013. © 2012 Wiley Periodicals, Inc.
POSS Core star‐shape molecular hybrid materials: Effect of the chain length and POSS content on dielectric properties
Authors: Ke Fuyou , Zhang Chao , Guang Shanyi , Xu Hongyao
Published: May 2012

A series of inorganic–organic molecular hybrids, poly(styrene‐co‐octavinyl‐polyhedral oligomeric silsesquioxane)s (PS‐POSSs), were synthesized, and their structures and properties were characterized by FTIR, 1H‐NMR, 29Si‐NMR, XRD, optical microscopy (OM), and atomic force microscopy (AFM). The chemical incorporation of POSS into polymer matrixes achieves uniform dispersion and makes the resultant hybrids display good film formability. The relationship between molecular structure of these hybrids and their dielectric constants and formation mechanism of low dielectric constant were investigated. The low dielectric constant of the hybrids mainly originates from the increase of free volume, involving the free volume of intrinsic porosity from POSS and an increase in the free volume owing to steric hindrance of bulky POSS. The latter plays a dominant role to increase the free volume and formation of low dielectric constant. Simultaneously, the polymer arm‐length has an important influence on the dielectric constant of the star‐type hybrids. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Influence of organic liquids on the nanostructure of precipitated cellulose
Authors: Watson Brian J. , Hammouda Boualem , Briber Robert M. , Hutcheson Steven W.
Published: May 2012

Organic liquids have been used in pretreatments to improve the digestibility of lignocellulosic biomass, ultimately reducing the amount of enzyme required to digest the material to its constituent sugars. To understand the influence of these solvents on cellulose nanostructure, phosphoric acid was used to solubilize cellulose (PAS cellulose) followed by washing of the PAS cellulose with organic liquids previously demonstrated to aid pretreatment. PAS cellulose washed using methanol, ethanol, and ethylene glycol had gel‐like properties with disrupted nanostructures. PAS cellulose washed with acetone, 2‐propanol, and water yielded an opaque white precipitate. Small‐angle neutron scattering indicated the formation of loosely bundled rods of cellulose in the gel‐like material. Fourier transform infrared resonance of solvent‐washed, flash‐dried PAS cellulose suggested an increase in interchain hydrogen bonds in the gel‐like precipitates relative to the more obvious precipitates formed in other solvents. The optimal wash liquid was determined to be 40% by volume ethanol in water to induce a highly digestible, gel‐like material. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Waterborne cationomer polyurethane coatings with improved hydrophobic properties
Authors: Król Piotr , Król Bożena , Stagraczyński Ryszard , Skrzypiec Krzysztof
Published: May 2012

The AFM method was used to investigate the phase structure of the coatings, which have been obtained after application of polyurethane cationomers, synthesized in the reaction of 4,4′‐methylenebis(phenyl isocyanate) or isophorone diisocyanate with polyoxyethylene glycol (M = 600) and N‐methyl or N‐butyldiethanolamine with 2,2,3,3‐tetrafluoro‐1,4‐butanediol. Changes were discussed in the surface‐free energy (SFE) and its components, as calculated independently according to the method suggested by van Owens–Wendt, in relation to chemical structures of cationomers, as well as morphology of coating surfaces obtained from those cationomers. Fluorine incorporated into cationomers (about 2–5%) contributed to lower SFE values, down to about 30 mJ/m2. An attempt was made to use 1H‐NMR spectroscopy to provide more extensive grounds for the effect of polyurethane chemical structures (by parameters κ) on the SFE of coatings obtained from such polyurethanes, with the values of SFE (γS, γ) and determined by the Owens–Wendt method. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and investigation of the β‐nucleated polypropylene/polystyrene blends
Authors: Zhang Zishou , Wang Chunguang , Du Yifei , Zhang Junping , Mai Kancheng
Published: May 2012

In this work, β‐polypropylene/polystyrene (β‐PP/PS) blends were prepared with PP, PS, and a novel supported β‐nucleating agent or β‐nucleated PP and PS. The β‐PP/PS blends were compatabilized by PP‐g‐MA, PP‐g‐GMA, POE‐g‐MA, and EVA‐g‐MA, respectively. For exploring the effect of PS amount and compatibilizers on the β‐nucleation of PP, crystallization behavior and melting characteristics, the β‐crystal content and crystal morphology of β‐PP are characterized by differential scanning calorimetry (DSC), wide angle X‐ray diffraction (WAXD), and polarized light microscopy (POM). The results indicated that the PP with high content of β‐crystal was obtained by addition of CaCO3 supported β‐nucleating agent (β‐NA) into PP. The β‐nucleation, crystallization behavior, and melting characteristics, and the β‐crystal content of β‐PP in these blends were not influenced by addition of PS and its amount. However, the increased content of PS decreased the size of β‐spherulites of PP in these blends. The β‐nucleation of PP in compatabilized blends slightly depended on the compatibilizers. β‐PP/PS blends with high β‐crystal content can easily be prepared. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Creep behavior of PLA‐based biodegradable plastic exposed to a hydrocarbon liquid
Authors: Widiastuti Indah , Sbarski Igor , Masood S.H.
Published: May 2012

This study explores the effect of hydrocarbon liquid on creep behavior of polylactic acid (PLA)‐based plastic. Evolution of the mechanical properties of the material was investigated experimentally by measurement of creep under tensile load. Tensile creep behavior was studied with a constant load over a temperature range from 30 to 50°C using specimens containing different levels of liquid. It was shown that the hydrocarbon liquid diffusion obeys the Fickian law of diffusion. The viscoelastic properties vary with temperature and these properties dramatically decrease above the glass transition temperature (Tg). Significant decreases in modulus and in the peak of tan δ were observed with an increase in liquid concentration at low temperatures. In contrast, at high temperatures, drier material recorded lower storage modulus. However, only small changes ofTgwere recorded. Dependence of compliance on temperature was observed in the creep test at all levels of liquid content. With respect to drier samples, it was noted that the high liquid content material had a lower rate of increasing creep strain with temperature. Therefore, at elevated temperatures, higher creep strain of dry specimens was observed compared to those with a higher liquid content. The improvement of creep resistance and stiffening of material at high temperatures can be attributed to the significant increase of crystallinity fraction induced by liquid absorption. Understanding the effect of liquid diffusion in conjunction with temperature provides useful information for assessment of the potential use of this biodegradable plastic in load‐bearing applications exposed to an organic liquid. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of surface modifiers and surface modification methods on properties of acrylonitrile–butadiene–styrene/poly(methyl methacrylate)/nano‐calcium carbonate composites
Authors: Zhang Aimin , Zhao Guoqun , Guan Yanjin
Published: May 2012

Nano‐calcium carbonate (nano‐CaCO3) was used in this article to fill acrylonitrile–butadiene–styrene (ABS)/poly(methyl methacrylate) (PMMA), which is often used in rapid heat cycle molding process (RHCM). To achieve better adhesion between nano‐CaCO3 and ABS/PMMA, nano‐CaCO3 particles were modified by using titanate coupling agent, aluminum–titanium compound coupling agent, and stearic acid. Dry and solution methods were both utilized in the surface modification process. ABS/PMMA/nano‐CaCO3 composites were prepared in a corotating twin screw extruder. Influence of surface modifiers and surface modification methods on mechanical and flow properties of composites was analyzed. The results showed that collaborative use of aluminum–titanium compound coupling agent and stearic acid for nano‐CaCO3 surface modification is optimal in ABS/PMMA/nano‐CaCO3 composites. Coupling agent can increase the melt flow index (MFI) and tensile yield strength of ABS/PMMA/nano‐CaCO3 composites. The Izod impact strength of composites increases with the addition of titanate coupling agent up to 1 wt %, thereafter the Izod impact strength shows a decrease. The interfacial adhesion between nano‐CaCO3 and ABS/PMMA is stronger by using solution method. But the dispersion uniformity of nano‐CaCO3 modified by solution method is worse. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Highly sensitive toluene vapor sensors using carbon black/amino‐functional copolymer composites
Authors: Matsuguchi Masanobu , Asahara Koji , Mizukami Takashi
Published: May 2012

An amino‐functional copolymer [N,N,‐dimethyl‐1,3‐propanediamine (MCD)] developed in our laboratory was blended with carbon black (CB/MCD composite) and its electrical responses to toluene vapor at low concentrations were measured at 30°C. When exposed to 200 ppm of toluene vapor, the CB/MCD sensor responded at S = 0.04 (S was obtained by dividing the relative change in the resistance of the sensor upon exposure to toluene vapor by the baseline resistance), demonstrating its ability to detect toluene vapor at low concentrations. The response was affected by humidity in the atmosphere due to the hydrophilic nature of MCD film; however, the behavior was reproducible before and after exposure of the sensor to the humid atmosphere. In addition, in 10 consecutive sorbing/desorbing cycles, it was confirmed that the changes in the resistance of the CB/MCD sensor were reproducible. These favorable sensing characteristics were attributed to vapor sorption behavior arising from the glassy and loosely crosslinked nature of MCD and explained by the dual‐sorption model. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and characterization of acrylic polymer nanocomposite films obtained from aqueous dispersions
Authors: Carneiro Catarina , Vieira Ricardo , Mendes Adélio M. , Magalhães Fernão D.
Published: May 2012

A functionalized fumed silica was dispersed in water using a nonionic surfactant, yielding a stable nanodispersion. This was blended with an aqueous acrylic polymer dispersion to produce hybrid nanocomposite films. The silica particles were shown to be well dispersed in the polymer matrix, with little agglomeration. Further evidence of good compatibility between the silica and acrylic polymer was given by the improved thermal stability of the nanocomposite compared with the pristine polymer. The nanocomposite films exhibited significantly lower dirt pick‐up behavior, which seems to be associated to the nanoroughness of the composite film surface observed in AFM analysis. This decreases the contact area between film and micrometric dirt particles. Surface tension and hardness do not seem to be significantly different in the composite and noncomposite materials. This approach may provide a strategy to obtain hybrid coatings with self‐cleaning properties, taking advantage of the relatively low cost, and large availability of fumed silica. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Effect of end‐capped nanosilica on mechanical properties and microstructure of LLLDPE/EVA blends
Authors: Heidary Mahmud , Jafari Seyed Hassan , Khonakdar Hossein Ali , Wagenknecht Udo , Heinrich Gert , Boldt Regine
Published: May 2012

This article describes the influence of a hexamethyldisilane‐treated nanosilica (end‐capped SiO2) on morphological and tensile properties of linear low‐density polyethylene (LLDPE)/ethylene vinyl acetate copolymer (EVA) blends prepared by one step melt mixing process via a twin screw extruder. The treatment replaces many of the surface hydroxyl groups on the nanosilica with extremely hydrophobic trimethylsilyl groups. Transmission electron microscopic results revealed that the treated nanosilica formed small aggregates in polymer matrix and they were mostly localized in the LLDPE matrix besides localizing in EVA droplets and at LLDPE/EVA interface. These nanoparticles had compatibilizing role on the blend system and at high content changed morphology from biphasic toward a monophasic. Addition of the end‐capped nanosilica to the blend and increasing its content increased the Young's modulus, tensile strength as well as elongation at break of the nanocomposites. Different models were used to predict the Young's modulus of the nanocomposites. It was found that the experimental data were better fitted by Counto model than the other models. Melt rheological investigations on the nanosilica filled LLDPE/EVA blend system showed that incorporation of the treated nanosilica, even up to 10 wt %, did not lead to a solid‐like behavior at low‐frequency indicating ease of processing of such highly filled system. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Structure and property of polyurethane/SiO2 composite elastomer prepared via in situ polymerization
Authors: Ding Jingjing , Ye Lin
Published: May 2012

A series of polyurethane (PU)/SiO2 composites were prepared via in situ polymerization through a prepolymer process. The effect of SiO2 content on mechanical and solvent‐resistant properties of PU/SiO2 composites was investigated. It was found that with increasing SiO2 content, the tensile strength and toughness, hardness, and modulus of PU composites increased. PU/SiO2 composites exhibited only one loss peak corresponding to the glass transition temperature of the soft‐segment of PU, which shifted insignificantly with increasing SiO2 content. The equilibrium swelling ratio and swelling rate constant in cyclohexanone and xylene were reduced by increasing SiO2 content, indicating the enhancement of the solvent resistance of the PU elastomer. Morphology observation of PU/SiO2 composites showed that the acicular SiO2 dispersed uniformly in PU matrix, and there was no obvious aggregation even at 9 wt % loading of SiO2. The reinforcing and toughening effects depended largely on the dispersion of SiO2 in PU matrix and the interfacial layer formed between the two phases. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Preparation and characterization of polyethylene/silver nanocomposite films with antibacterial activity
Authors: Dehnavi Arefeh Sadat , Aroujalian Abdolreza , Raisi Ahmadreza , Fazel Shahrzad
Published: May 2012

In this work, a novel method was proposed for the fabrication of antibacterial nanocomposite polymeric films, for use in food packaging. In the first step, a stable colloidal solution of silver nanoparticles was prepared by chemical reduction of silver salt using fructose as an environmental friendly reducing agent. In the second step, corona air plasma was used as a pretreatment of low density polyethylene (LDPE) films to increase the adhesion of silver nanoparticles on the film surface. In the third step, silver nanoparticles were coated on the LDPE surface by immersion of the treated films in the colloidal silver solutions. Surface morphology of the silver/LDPE nanocomposite was characterized by FE‐SEM and AFM analysis. The amounts of coated silver and silver ion release from the nanocomposite surface were determined. In addition, the antibacterial activity of the fabricated films was evaluated by agar well diffusion and dynamic shake flask methods. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Tripodal “click” ligands for copper‐catalyzed ATRP
Authors: Sangtrirutnugul Preeyanuch , Maisopa Purmpoon , Chaicharoenwimolkul Laksamee , Sunsin Atchariya , Somsook Ekasith , Reutrakul Vichai
Published: May 2012

A series of tris(R‐methyltriazolylmethyl)amines [R = C6H5 (1), 4‐FC6H4 (2), 4‐MeOC6H4 (3), Fc (4)] were prepared and used as ligands for catalytic ATRP of methyl methacrylate (MMA). Despite a lower activity, the CuBr/4 catalyst promoted relatively well controlled polymerization compared to CuBr/1, as evidenced by narrower polydispersity indices. Meanwhile, no polymerization activity was observed with CuBr/2 and CuBr/3 under the catalytic conditions investigated. The CV measurements of CuBr2 complexes supported 1 and 4 in DMSO showed E1/2 values of –0.206 and –0.224 V, respectively, confirming the more electron‐rich nature of CuBr/4. Although both CuBr/1 and CuBr/4 catalysts were only partially soluble in several organic solvents used, kinetic studies revealed a pseudo first order linear plot of ln[M]0/[M]t versus time. Addition of CuBr2 into the polymerization systems led to a decrease in polymer polydispersities and the observed rate constants (kobs). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Poly(N‐hydroxyethyl acrylamide)‐b‐polystyrene by combination of ATRP and aminolysis processes
Authors: Gunes Deniz , Batu Kurtarel Omer , Bicak Niyazi
Published: May 2012

Block copolymers of very hydrophilic poly(N‐hydroxyethyl acrylamide) (PHEAA) with polystyrene (PS) were successfully synthesized by sequential atom transfer radical polymerization of ethyl acrylate (EA) and styrene monomers and subsequent aminolysis of the acrylic block with ethanolamine. Quantitative aminolysis of poly(ethyl acrylate) (PEA) block yielded poly(N‐hydroxyethyl acrylamide)‐b‐polystyrene in well‐defined structures, as evidenced by Fourier transform infrared spectroscopy (FTIR) and 1H‐NMR spectroscopy techniques. Three copolymers with constant chain length of PHEAA (degree of polymerization: 80) and PS blocks with 21, 74, and 121 repeating units were prepared by this method. Among those, the block copolymer with 21 styrene repeating units showed excellent micellation behavior in water without phase inversion below 100°C, as inferred from dynamical light scattering, environmental scanning electron microscopy, and fluorescence measurements. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Molecular composites obtained by polyaniline synthesis in the presence of p‐octasulfonated calixarene macrocycle
Authors: Grigoras Mircea , Catargiu Ana Maria , Tudorache Florin
Published: May 2012

Polyaniline (PANI) molecular composites were synthesized by chemical oxidative polymerization of the aniline and aniline dimer, N‐phenyl‐1,4‐phenylendiamine, in the presence of a macrocycle, calix[8]arene p‐octasulfonic acid (C8S), using ammonium peroxidisulfate as oxidant. The macrocycle has acted both as acid dopant and surfactant to obtain processable PANI‐ES. The PANI/calix[8]arene p‐octasulfonic acid composite was also obtained by a simple doping of PANI emeraldine base form with calix[8]arene sulfonic acid. The structure of materials was confirmed by Fourier transform infrared, UV–vis and nuclear magnetic resonance spectroscopy. All synthesized composite materials are amorphous and soluble in chloroform, dimethylsulfoxide, NMP, showing excellent solution‐processing properties combined with electrical conductivity. Cyclic voltammetry evidenced a good electroactivity for the composite films. Dielectric properties (dielectric constant and dielectric losses) were determined and are comparable with those of other PANI/ionic acid polymer composites. Preliminary studies have evidenced a high dielectric constant (104 at 100 Hz) and electrical conductivity of 6 × 10−3 S/cm for PANI composites. From sulfur elemental analysis of the PANI/calixarene, it results that the content in macrocycle is ∼30% (weight). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Dye removal from colored‐textile wastewater using chitosan‐PPI dendrimer hybrid as a biopolymer: Optimization, kinetic, and isotherm studies
Authors: Sadeghi‐Kiakhani Mousa , Arami Mokhtar , Gharanjig Kamaladin
Published: May 2012

Preparation of a biopolymer chitosan‐polypropylene imine (CS‐PPI) as a biocompatible adsorbent and its reactive textile dyes removal potential were performed. Chemical specifications of CS‐PPI were determined using Fourier transform infrared, 1H‐NMR, and 13C‐NMR. The surface morphology of the CS‐PPI surface was characterized by scanning electron microscopy. Results confirmed that the linkages between the NH2 groups of PPI dendrimer and carboxylic groups of modified Chitosan were accomplished chemically. Two textile reactive dyes, reactive black 5 (RB5) and reactive red 198 (RR198), were used as model compounds. A response surface methodology was applied to estimate the simple and combined effects of the operating variables, including pH, dye concentration, time contact, and temperature. Under the optimal values of process parameters, the dye removal performance of 97 and 99% was achieved for RB5 and RR198, respectively. Furthermore, the isotherm and kinetic models of dyes adsorption were performed. Adsorption data represented that both examined dye followed the Langmuir isotherm. The adsorption kinetics of both reactive dyes were satisfied by pseudo‐second order equation. Based on this study, CS‐PPI due to having high adsorption capacity (6250 mg/g for RB5 and 5882.35 mg/g for RR198), biocompatibility and ecofriendly properties might be a suitable adsorbent for removal of reactive dyes from colored solutions. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
The effect of multiple variables on tensile property of injection‐molded polypropylene through the combination of orthogonal design and variance analysis
Authors: Hu Juan , Gao Xueqin , Chen Zhanchun , Shen Kaizhi , Deng Cong
Published: May 2012

In this article, a combination of orthogonal design and variance analysis was used to study the systematical effect of vibration pressure, melt temperature, packing cycle, and mold temperature on the tensile property of polypropylene in dynamic packing injection molding (DPIM). The tensile measurement results show that all variables had significant influence on the final tensile property under the present molding condition. Meanwhile, the optimal molding condition to achieve high tensile strength was also obtained in the investigated ranges. Further quantitative statistical analysis revealed the degree of influence of four variables on the tensile property of polypropylene in DPIM. The sequence of the degree of influence from maximum to minimum is as follow: vibration pressure, melt temperature, packing cycle, and mold temperature. These findings provide the experimental and statistical evidences to illustrate that the application of orthogonal design and variance analysis might be an effective approach to systematically study the effect of multiple variables on the final mechanical property. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013
Controller Synthesis with Highly Simplified Linear Constraints
Authors: Dideban Abbas , Zareiee Meysam , Alla Hassane
Published: May 2012

This paper deals with the problem of forbidden states in safe Petri nets to obtain a maximally permissive controller. To prevent the system from entering the forbidden states, assigning some constraints to them is possible. The constraints can be enforced on the system using control places. When the number of forbidden states is large, a large number of constraints should be assigned to them. This results in a large number of control places being added to the model of the system, which causes a complicated model. Some methods have been proposed to reduce the number of constraints. Nevertheless, they do not always give the best results. In this paper, two ideas are offered to reduce the number of constraints, giving a more simplified controller.
Massive Human Co‐Expression Network and Its Medical Applications
Authors: Feng Yaping , Hurst Jonathan , Almeida‐De‐Macedo Marcia , Chen Xi , Li Ling , Ransom Nick , Wurtele Eve Syrkin
Published: May 2012

Network‐based analysis is indispensable in analyzing high‐throughput biological data. Based on the assumption that the variation of gene interactions under given biological conditions could be better interpreted in the context of a large‐scale and wide variety of developmental, tissue, and disease conditions, we leverage the large quantity of publicly available transcriptomic data >40,000 HG U133A Affymetrix microarray chips stored in ArrayExpress (http://www.ebi.ac.uk/arrayexpress/) using MetaOmGraph (http://metnet.vrac.iastate.edu/MetNet_MetaOmGraph.htm). From this data, 18,637 chips encompassing over 500 experiments containing high‐quality data (18637 Hu‐dataset) were used to create a globally stable gene co‐expression network (18637 Hu‐co‐expression‐network). Regulons, groups of highly and consistently co‐expressed genes, were obtained by partitioning the 18637 Hu‐co‐expression‐network using an Markov clustering algorithm (MCL). The regulons were demonstrated to be statistically significant using a gene ontology (GO) term overrepresentation test combined with evaluation of the effects of gene permutations. The regulons include ca. 12% of human genes, interconnected by 31,471 correlations. All network data and metadata are publically available (http://metnet.vrac.iastate.edu/MetNet_MetaOmGraph.htm). Text mining of these metadata, GO term overrepresentation analysis, and statistical analysis of transcriptomic experiments across multiple environmental, tissue, and disease conditions, has revealed novel fingerprints distinguishing central nervous system (CNS)‐related conditions. This study demonstrates the value of mega‐scale network‐based analysis for biologists to further refine transcriptomic data, derived from a particular condition, to study the global relationships between genes and diseases, and to develop hypotheses that can inform future research.
Nested Hierarchal Organization of Conservation for MicroRNAs and Their Putative Targets to Drosophila melanogaster
Authors: Woodcock M. Ryan
Published: May 2012

This study examined microRNA network properties traced through taxonomic hierarchy considering both the acquisition of potential network targets and regulators. Primary literature review and database analyses were conducted to establish modules of conserved microRNAs across metazoan taxonomy. A hierarchical schema for the conservation of microRNAs and their putative targets to Drosophila melanogaster was engineered through comprehensive meta‐analysis, and conservation history of 90.39% of the total Drosophila dataset could be resolved through this hierarchical sampling regime; tracing from taxonomic order down to empire. The findings presented in this study represent a documentation of Drosophila microRNA regulatory network behavior thorough taxonomic hierarchy. MicroRNA regulatory network properties were found to transect taxonomic hierarchy. Newly acquired microRNAs from novel families reinforce the pre‐existing regulatory network, while expanding the target list to include a small number of novel genes. Lineage specific microRNAs were found to exhibit far fewer conserved targets than do the more broadly conserved microRNAs; even when considering only more recently emerged targets. There was a dramatic expansion in network complexity with the expansion of the microRNA repertoire, and this corresponds to the expansion in biological complexity.
Predicting Antigenicity of Proteins in a Bacterial Proteome; a Protein Microarray and Naïve Bayes Classification Approach
Authors: Liang Li , Felgner Philip L.
Published: May 2012

Discovery of novel antigens associated with infectious diseases is fundamental to the development of serodiagnostic tests and protein subunit vaccines against existing and emerging pathogens. Efforts to predict antigenicity have relied on a few computational algorithms predicting signal peptide sequences (SignalP), transmembrane domains, or subcellular localization (pSort). An empirical protein microarray approach was developed to scan the entire proteome of any infectious microorganism and empirically determine immunoglobulin reactivity against all the antigens from a microorganism in infected individuals. The current database from this activity contains quantitative antibody reactivity data against 35,000 proteins derived from 25 infectious microorganisms and more than 30 million data points derived from 15,000 patient sera. Interrogation of these data sets has revealed ten proteomic features that are associated with antigenicity, allowing an in silico protein sequence and functional annotation based approach to triage the least likely antigenic proteins from those that are more likely to be antigenic. The first iteration of this approach applied to Brucella melitensis predicted 37% of the bacterial proteome containing 91% of the antigens empirically identified by probing proteome microarrays. In this study, we describe a naïve Bayes classification approach that can be used to assign a relative score to the likelihood that an antigen will be immunoreactive and serodiagnostic in a bacterial proteome. This algorithm predicted 20% of the B. melitensis proteome including 91% of the serodiagnostic antigens, a nearly twofold improvement in specificity of the predictor. These results give us confidence that further development of this approach will lead to further improvements in the sensitivity and specificity of this in silico predictive algorithm.
Integration of Diverse Statistical Evidence of GeneTrait Association in Systems Biology Studies
Authors: Cheng Cheng
Published: May 2012

The rapid advancement of high‐throughput genomic assay technologies has generated large amounts of diverse genomic data in disparate human populations and diseases. These data provide a unique opportunity for biomedical investigators to systematically study multifaceted aspects of genes' involvement in the biological processes underlying important traits from the systems biology perspective. An important component in such a study is the inference that integrates diverse lines of statistical evidence for genetrait association from the observed trait values and the massive numbers of measured genomic features. A novel integrated statistical analysis procedure is developed in this paper and is illustrated by an application in studying childhood leukemia.
Prediction and Comparison of SalmonellaHuman and SalmonellaArabidopsis Interactomes
Authors: Schleker Sylvia , Garcia‐Garcia Javier , Klein‐Seetharaman Judith , Oliva Baldo
Published: May 2012

Salmonellosis caused by Salmonella bacteria is a food‐borne disease and a worldwide health threat causing millions of infections and thousands of deaths every year. This pathogen infects an unusually broad range of host organisms including human and plants. A better understanding of the mechanisms of communication between Salmonella and its hosts requires identifying the interactions between Salmonella and host proteins. Proteinprotein interactions (PPIs) are the fundamental building blocks of communication. Here, we utilize the prediction platform BIANA to obtain the putative Salmonellahuman and SalmonellaArabidopsis interactomes based on sequence and domain similarity to known PPIs. A gold standard list of Salmonellahost PPIs served to validate the quality of the human model. 24,726 and 10,926 PPIs comprising interactions between 38 and 33 Salmonella effectors and virulence factors with 9,740 human and 4,676 Arabidopsis proteins, respectively, were predicted. Putative hub proteins could be identified, and parallels between the two interactomes were discovered. This approach can provide insight into possible biological functions of so far uncharacterized proteins. The predicted interactions are available via a web interface which allows filtering of the database according to parameters provided by the user to narrow down the list of suspected interactions. The interactions are available via a web interface at http://sbi.imim.es/web/SHIPREC.php.
Newborn Umbilical Cord Blood DNA Methylation and Gene Expression Levels Exhibit Limited Association with Birth Weight
Authors: Adkins Ronald M. , Tylavsky Frances A. , Krushkal Julia
Published: May 2012

Most cases of fetal growth retardation are unexplained. These newborns are at high risk of serious illness or death in the neonatal period and exhibit significantly increased risk of specific chronic illnesses later in life. While there are several hypotheses to explain the well‐established association between low birth weight and later risk of disease, the true etiology is unknown. To search for molecular patterns that may explain the biological basis for reduced fetal growth in a clinically normal cohort, and possibly provide clues for the lifelong increased risk of disease, we surveyed genome‐wide DNA methylation and gene expression patterns in the umbilical cord blood of newborns born in Shelby County, TN. While we did not find genome‐wide significant associations of birth weight with either leukocytic gene expression or DNA methylation, we did find suggestive associations in several genes with known effects on pre‐ or postnatal growth and health. As with previous molecular epidemiological studies of birth weight, we did not sample the most biologically relevant tissues in the newborn. However, our discovery of biologically plausible associations in a peripheral tissue suggests that further studies of tissues key to fetal growth regulation are warranted.