bluuebunny/crossref_metadata_2025 huggingface dataset:
Butyl chloride as promoter in ethylene polymerization by magnesium ethoxide‐supported catalyst
Authors: Abedi Sadegh , Azadi Farhad , Daftari‐Besheli Majid , Majdabadi‐Farahani Noushin , Safinejad Ali
Published: November 2013

The effects of butyl chloride as a promoter in the ethylene polymerization were studied using a Mg(OEt)2/TiCl4/triethyl aluminum (TEA) Ziegler–Natta catalyst system, where Mg(OEt)2, TiCl4, TEA were used as support, catalyst, and activator, respectively. The influence of BC on the catalyst performance, polymerization rate, and polymer properties were investigated. This study strongly indicates that BC could act as a promoter with high performance in the ethylene polymerization. There was a remarkable increase in the catalyst yield and polymerization rate, in particularly, in the presence of hydrogen which was used for controlling the molecular weight. A reduction in the polymer molecular weight was observed in the presence of BC and hydrogen. The morphology of the polymers was evaluated through scanning electron microscopy and particle size distribution. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2014,131, 40189.
Synthesis of novel polyaniline/MgO composite for enhanced adsorption of reactive dye
Authors: Pandiselvi K. , Manikumar A. , Thambidurai S.
Published: November 2013

In this investigation, the porous structure of polyaniline/MgO (PANI/MgO) composites has been successfully synthesized by in‐situ oxidative polymerization method. The as‐prepared materials were characterized by Ultraviolet–visible absorption spectroscopy, Fourier transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy. The obtained composites, for the first time, are used as an adsorbent for the removal of the sulfonated anionic dye reactive orange 16 (RO) from aqueous solution. The equilibrium adsorption isotherms of RO on the PANI/MgO composites were analyzed by Langmuir and Freundlich models, suggesting that the Langmuir model provides the better correlation of the experimental data and maximum adsorption capacity was found to be 558.4 mg g−1. In addition, adsorption kinetics was followed by both pseudo‐first‐order and pseudo‐second‐order, but the latter model matches the results much better than the former one. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40210.
The preparation and properties study of methoxy functionalized silicone‐modified epoxy resins
Authors: Ren Qinyu , Zou Huawei , Liang Mei
Published: November 2013

In this work, a series of siloxane epoxy resins (E3074) were synthesized through reaction of poly(methylphenylsiloxane) (DC‐3074) with epoxy resin. The chemical structure of the resultant epoxy resin was determined by FTIR, GPC, and epoxy equivalent weight (EEW) tests. The mechanical measurements indicated that the tensile strength of E3074 was lower than that of neat epoxy resin after modification, while their elongations at break improved markedly when compared with that of epoxy resin. SEM revealed that the particle size of silicone had a significant effect on the mechanical properties of the modified epoxy resin. TGA results showed that the thermal stability of E3074 serials was better than that of epoxy resin. The char residue of E3074 at 600°C increased with the incremental content of silicone. DMA tests displayed that the addition of silicone effectively enhanced the damping properties of epoxy resin. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40212.
Early diagnosis of necrotizing fasciitis
Authors: Goh T , Goh L G , Ang C H , Wong C H
Published: November 2013

Background

Necrotizing fasciitis is a rapidly progressing skin infection characterized by necrosis of the fascia and subcutaneous tissue, accompanied by severe systemic toxicity. The objective of this systematic review was to identify clinical features and investigations that will aid early diagnosis.

Methods

A systematic literature search of PubMed was undertaken using the keywords ‘necrotising fasciitis’, ‘necrotising skin infection’, ‘diagnosis’ and ‘outcome’. Case series of 50 or more subjects with information on symptoms and signs at initial presentation, investigations and clinical outcome were included.

Results

Nine case series were selected, with a total of 1463 patients. Diabetes mellitus was a co-morbidity in 44·5 per cent of patients. Contact with marine life or ingestion of seafood in patients with liver disease were risk factors in some parts of Asia. The top three early presenting clinical features were: swelling (80·8 per cent), pain (79·0 per cent) and erythema (70·7 per cent). These being non-specific features, initial misdiagnosis was common and occurred in almost three-quarters of patients. Clinical features that helped early diagnosis were: pain out of proportion to the physical findings; failure to improve despite broad-spectrum antibiotics; presence of bullae in the skin; and gas in the soft tissue on plain X-ray (although this occurred in only 24·8 per cent of patients).

Conclusion

A high index of suspicion of necrotizing fasciitis is needed in a patient presenting with cutaneous infection causing swelling, pain and erythema, with co-morbidity of diabetes or liver disease. The presence of bullae, or gas on plain X-ray can be diagnostic. Early surgical exploration is the best approach in the uncertain case.
Kinetic Modeling of the Gas Antisolvent Process for Synthesis of 5‐Fluorouracil Nanoparticles
Authors: Esfandiari Nadia , Ghoreishi Seyyed M.
Published: November 2013

Mathematical modeling for 5‐fluorouracil (5‐FU) nanoparticle synthesis via gas antisolvent (GAS) process was investigated. 5‐FU was precipitated from a dimethyl sulfoxide (DMSO) solution using CO2 as antisolvent. The particle size was controlled by nucleation and growth rates, therefore, the kinetic modeling study is essential. Thermodynamic modeling was applied to determine optimal operating conditions for experimental 5‐FU synthesis. Kinetic parameters were evaluated by fitting the particle size distribution predicted by the model to experimental data. The experimental and modeling results indicated that the particle size decreased with increasing the antisolvent addition rate.
Coadsorption Equilibria of Automotive Fuel Vapors on Wet Activated Carbon Filters
Authors: Göbel Manfred U. , Lange Marcus , Meller Karl , Möller Andreas , Schieferstein Eva , Seeger Thomas , U. Keller Jürgen
Published: November 2013

Kraftstoffdampf‐Rückhaltesysteme in PKWs enthalten gewöhnlich einen Aktivkohlefilter an dem die flüchtigen Kraftstoffkomponenten adsorbieren. Kurz vor Durchbruch dieser Stoffe wird die Zufuhr der Dämpfe unterbrochen und der Filter mithilfe von Umgebungsluft regeneriert. Da die Luft feucht ist, wird untersucht, ob im langjährigen Betrieb Wasser auf dem Filter kumuliert und so die Beladekapazität und Funktionsfähigkeit beeinträchtigt wird. Die Kosorptionsgleichgewichte von Wasser und n‐Pentan auf Aktivkohle wurden gemessen. Die Gemischbeladungen weichen nur wenig von den Summen der Reinstoffbeladungen beider Komponenten ab. Auch bei extremer Vorbefeuchtung der Kohle ist nur eine geringe Reduktion der Pentanbeladungskapazität zu beobachten.
Cortical inputs innervate calbindin‐immunoreactive interneurons of the rat basolateral amygdaloid complex
Authors: Unal Gunes , Paré Jean‐Francois , Smith Yoland , Paré Denis
Published: November 2013

The present study was undertaken to shed light on the synaptic organization of the rat basolateral amygdala (BLA). The BLA contains multiple types of GABAergic interneurons that are differentially connected with extrinsic afferents and other BLA cells. Previously, it was reported that parvalbumin immunoreactive (PV+) interneurons receive strong excitatory inputs from principal BLA cells but very few cortical inputs, implying a prevalent role in feedback inhibition. However, because prior physiological studies indicate that cortical afferents do trigger feedforward inhibition in principal cells, the present study aimed to determine whether a numerically important subtype of interneurons, expressing calbindin (CB+), receives cortical inputs. Rats received injections of the anterograde tracerPhaseolus vulgaris‐leucoagglutinin (PHAL) in the perirhinal cortex or adjacent temporal neocortex. Light and electron microscopic observations of the relations between cortical inputs and BLA neurons were performed in the lateral (LA) and basolateral (BL) nuclei. Irrespective of the injection site (perirhinal or temporal neocortex) and target nucleus (LA or BL), ∼90% of cortical axon terminals formed asymmetric synapses with dendritic spines of principal BLA neurons, while 10% contacted the dendritic shafts of presumed interneurons, half of which were CB+. Given the previously reported pattern of CB coexpression among GABAergic interneurons of the BLA, these results suggest that a subset of PV‐immunonegative cells that express CB, most likely the somatostatin‐positive interneurons, are important mediators of cortically evoked feedforward inhibition in the BLA. J. Comp. Neurol. 522:1915–1928, 2014. © 2013 Wiley Periodicals, Inc.
Utility of P16 expression and Ki‐67 proliferation index in ASCUS and ASC‐H pap tests
Authors: Toll Adam D. , Kelly Deidra , Maleki Zahra
Published: November 2013

Current cervical screening uses a combination of cytology and high‐risk human papillomavirus (HR‐HPV) analysis in cases of atypical squamous cells of undetermined significance (ASCUS) and atypical squamous cells cannot exclude high‐grade intraepithelial lesion (ASC‐H). These diagnoses are subject to interobserver variability and HR‐HPV analysis can be limited by sampling inadequacy. This study correlates immunoexpression of P16 and Ki‐67 in residual cervicovaginal material against cytology category and HR‐HPV status. Eighteen pap tests were selected: 8 ASCUS, 4 ASC‐H, and 6 controls (2 LSIL and 4 HSIL). Digene Hybrid Capture II test was used to detect HR‐HPV. The cytospins were stained for P16/Ki‐67. Pap tests, P16, Ki‐67, HR‐HPV result and available biopsies were correlated. P16 expression correlated with HR‐HPV status in 15/17 cases. Discordant cases (1 ASCUS and 1 ASC‐H) were +P16/–HR‐HPV. Ki‐67 correlated with HR‐HPV in 8/15 cases. Discordant cases were +HR‐HPV/– Ki‐67 (HSIL, LSIL, and ASC‐H one each), and –HR‐HPV/+Ki‐67 (3 ASCUS, 1 LSIL, 1 ASC‐H). Two cases were + P16/+ Ki‐67/– HR‐HPV. None were ‐ P16/– Ki‐67/+ HR‐HPV. Histologic follow‐up in 13 cases varied from benign to CIN III. Two cases of +P16/ – Ki‐67/– HR‐HPV had benign cervical biopcies. Although a small sample size, our findings show a utility for adjunct P16/ Ki‐67 in addition to HR‐HPV testing in cases of squamous atypia when HR‐HPVs are non‐detected due to low DNA copies, or missed lesions in cervical biopsies. Diagn. Cytopathol. 2014;42:576–581. © 2013 Wiley Periodicals, Inc.
Second messenger networks for accurate growth cone guidance
Authors: Akiyama Hiroki , Kamiguchi Hiroyuki
Published: November 2013

Growth cones are able to navigate over long distances to find their appropriate target by following guidance cues that are often presented to them in the form of an extracellular gradient. These external cues are converted into gradients of specific signaling molecules inside growth cones, while at the same time these internal signals are amplified. The amplified instruction is then used to generate asymmetric changes in the growth cone turning machinery so that one side of the growth cone migrates at a rate faster than the other side, and thus the growth cone turns toward or away from the external cue. This review examines how signal specification and amplification can be achieved inside the growth cone by multiple second messenger signaling pathways activated downstream of guidance cues. These include the calcium ion, cyclic nucleotide, and phosphatidylinositol signaling pathways. © 2013 Wiley Periodicals, Inc. Develop Neurobiol 75: 411–422, 2015
Fe(TAML)Li/(diacetoxyiodo)benzene‐Mediated Oxidation of Alcohols: Evidence for Mild and Selective C–O and C–C Oxidative Cleavage in Lignin Model Transformations
Authors: Napoly François , Jean‐Gérard Ludivine , Goux‐Henry Catherine , Draye Micheline , Andrioletti Bruno
Published: November 2013

A novel combination of Fe(TAML)Li and (diacetoxyiodo)benzene for the oxidation of primary and secondary alcohols at 25 °C in acetone is reported. In view of the interesting ability of this system to selectively cleave specific types of C–C bonds of elaborated alcohols, the application of this novel combination to the oxidative cleavage of lignin model molecules was investigated. Considering the numerous supported versions of the oxidant as well as the mild conditions employed, the developed methodology appears to be a promising lignin depolymerization strategy.
Annulations of α‐Carbamoyl Ketene Dithioacetals with Dicarboxylic Acid Dichlorides: Synthesis of Functionalized Pyrrolidinetriones and Piperidinetriones
Authors: Dong Ying , Guo Yaru , Liu Jun , Zheng Gang , Wang Mang
Published: November 2013

An annulation strategy based on ketene dithioacetals is described. Under very mild conditions, a number of pyrrolidinetriones 2 and piperidinetriones 3 have been synthesized by the cycloaddition reaction of α‐carbamoyl ketene dithioacetals 1 with di‐carboxylic acid dichlorides in good to excellent yields. Further application of this protocol is highlighted by the synthesis of a set of fused pyrimidine derivatives 4/5 from 2/3 and amidines.
The effects of counterfactual defences on social judgements
Authors: Catellani Patrizia , Bertolotti Mauro
Published: November 2013

Research on counterfactuals (‘If only…’) has seldom considered the effects of counterfactual communication, especially in a defensive context. In three studies, we investigated the effects of counterfactual defences employed by politicians. We assumed that self‐focused upward counterfactuals (‘If only I…, the outcome would have been better’) are a form of concession, other‐focused upward counterfactuals (‘If only they…, the outcome would have been better’) are a form of excuse, and self‐focused downward counterfactuals (‘If only I…, the outcome would have been worse’) are a form of justification. In Study 1, a counterfactual defence led to a more positive evaluation of the politician than a corresponding factual defence. Of the two types of defence, the counterfactual defence reduced the extent to which the politician was held responsible for the past event and was perceived as more convincing. In Study 2, counterfactual excuse and counterfactual justification were equally effective and led to a more positive evaluation of the politician than counterfactual concession. In Study 3, the higher effectiveness of counterfactual justification was independent from perceived ideological similarity with the politician, supporting the strength of this defence. These results show that counterfactual defences provide subtle communication strategies that effectively influence social judgements. Copyright © 2013 John Wiley & Sons, Ltd.
Biofuel Cell Based on Anode and Cathode Modified by Glucose Oxidase
Authors: Krikstolaityte Vida , Oztekin Yasemin , Kuliesius Jurgis , Ramanaviciene Almira , Yazicigil Zafer , Ersoz Mustafa , Okumus Aytug , Kausaite‐Minkstimiene Asta , Kilic Zeynel , Solak Ali Osman , Makaraviciute Asta , Ramanavicius Arunas
Published: November 2013

A single compartment biofuel cell (BFC) based on an anode and a cathode powered by the same fuel glucose is reported. Glucose oxidase (GOx) from Aspergillus niger was applied as a glucose consuming biocatalyst for both anode and cathode of the BFC. The 5‐amino‐1,10‐phenanthroline modified graphite rod electrode (GRE) with cross‐linked GOx was used as the bioanode, and the GRE with co‐immobilised horseradish peroxidase and GOx was exploited as the biocathode of the BFC. The open‐circuit voltage of the designed BFC exceeded 450 mV and a maximal power density of 3.5 µW/cm2 was registered at a cell voltage of 300 mV.
Comparative effects of sediment versus aqueous polychlorinated biphenyl (PCB) exposure on benthic and planktonic invertebrates
Authors: Nowicki Carly J. , van Hees Edmond H. , Kashian Donna R.
Published: November 2013

Polychlorinated biphenyls (PCBs) are an environmental concern because of their adverse effects on humans and wildlife, and understanding the contribution of various matrices (i.e., sediment and water) to PCB exposure on aquatic communities is critical for successful remediation of impacted sites. The present study examined the toxicity of different routes of PCB exposure in aquatic invertebrates. In complementary laboratory and field experiments, the authors compared the effects of aqueous versus sedimentary exposure of PCBs on invertebrates. In laboratory bioassays, the planktonic Daphnia pulex and benthic Chironomus dilutus exhibited significant mortality when exposed to PCB-contaminated (1100 µg/g) sediment (p = 0.03 and p < 0.01, respectively). In field experiments, adult Dreissena bugensis were placed in cages along a depth gradient at a reference site and a PCB-impacted site in St. Clair Shores, Michigan, USA. Mussels experienced significantly greater mortality (p < 0.001) when placed in close proximity to impacted-site sediments compared with reference sediments. After 7 d, 94% of D. bugensis survived at the reference site compared with only 57% surviving at the impacted site. In addition, D. bugensis at the impacted site experienced significantly less mortality at the water surface (p < 0.001) compared to those near the sediment. The present study demonstrates the importance of evaluating toxicity at the sediment–water interface. Environ Toxicol Chem 2014;33:641–647. © 2013 SETAC
Embryonic exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin impairs prey capture by zebrafish larvae
Authors: Chollett Danielle , Perez Kathryn E. , King-Heiden Tisha C.
Published: November 2013

As a ubiquitous, persistent environmental contaminant, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) has the potential to cause lethal deformities in larval fishes. Few studies have examined its impacts on larval growth and craniofacial development in conjunction with feeding capability. The authors used morphological and behavioral assessments to demonstrate that feeding capability of larvae is impaired even when craniofacial structures are not grossly malformed. Zebrafish embryos were exposed to 25 pg TCDD/mL, 50 pg TCDD/mL, or 100 pg TCDD/mL or <0.1% dimethyl sulfoxide for 1 h at 4 h postfertilization and then raised in clean water for 21 d or 90 d to assess craniofacial morphology, feeding capability, and long-term survival. The lower jaw was 5% smaller in 21-d larvae exposed to ≥50 pg TCDD/mL, and those larvae caught 10% fewer prey items; survival was reduced by 13% to 23%. The direct cause of TCDD's impacts on feeding capability is not known, but feeding success was correlated with growth, length of lower jaw, and survival. Since low larval mortality rates are key for recruitment, this suggests that exposure to concentrations of TCDD during embryonic development that do not initially cause mortality still has the potential to impact the recruitment success of feral fish. Furthermore, the present work provides additional evidence that behavioral end points are often more sensitive than morphological ones and should be included when assessing the sublethal toxicity of environmental contaminants. Environ Toxicol Chem 2014;33:784–790. © 2013 SETAC
Building Scenarios of Multiple Time Series that Take into Account the Effects of an Expected Intervention
Authors: Guerrero Víctor M. , Silva Eliud , Gómez Nicolás
Published: November 2013

We consider a forecasting problem that arises when an intervention is expected to occur on an economic system during the forecast horizon. The time series model employed is seen as a statistical device that serves to capture the empirical regularities of the observed data on the variables of the system without relying on a particular theoretical structure. Either the deterministic or the stochastic structure of a vector autoregressive error correction model of the system is assumed to be affected by the intervention. The information about the intervention effect is just provided by some linear restrictions imposed on the future values of the variables involved. Formulas for restricted forecasts with intervention effects and their mean squared errors are derived as a particular case of Catlin's static updating theorem. An empirical illustration uses Mexican macroeconomic data on five variables and the restricted forecasts consider targets for years 2011–2014. Copyright © 2013 John Wiley & Sons, Ltd.
Code interoperability and standard data formats in quantum chemistry and quantum dynamics: The Q5/D5Cost data model
Authors: Rossi Elda , Evangelisti Stefano , Laganà Antonio , Monari Antonio , Rampino Sergio , Verdicchio Marco , Baldridge Kim K. , Bendazzoli Gian Luigi , Borini Stefano , Cimiraglia Renzo , Angeli Celestino , Kallay Peter , Lüthi Hans P. , Ruud Kenneth , Sanchez‐Marin José , Scemama Anthony , Szalay Peter G. , Tajti Attila
Published: November 2013

Code interoperability and the search for domain‐specific standard data formats represent critical issues in many areas of computational science. The advent of novel computing infrastructures such as computational grids and clouds make these issues even more urgent. The design and implementation of a common data format for quantum chemistry (QC) and quantum dynamics (QD) computer programs is discussed with reference to the research performed in the course of two Collaboration in Science and Technology Actions. The specific data models adopted, Q5Cost and D5Cost, are shown to work for a number of interoperating codes, regardless of the type and amount of information (small or large datasets) to be exchanged. The codes are either interfaced directly, or transfer data by means of wrappers; both types of data exchange are supported by the Q5/D5Cost library. Further, the exchange of data between QC and QD codes is addressed. As a proof of concept, the H + H2 reaction is discussed. The proposed scheme is shown to provide an excellent basis for cooperative code development, even across domain boundaries. Moreover, the scheme presented is found to be useful also as a production tool in the grid distributed computing environment. © 2013 Wiley Periodicals, Inc.
GENDER INEQUALITY AND ECONOMIC GROWTH: A CRITICAL REVIEW
Authors: Cuberes David , Teignier Marc
Published: November 2013

The link between gender inequality and economic growth is a topic that is of growing interest, both in the academic literature and the policy arena. In this paper, we survey the literature that analyses this relationship from a macroeconomic perspective. We argue that that the existing theories provide a wide range of mechanisms through which these two variables may affect each other but also that more work needs to be carried out to obtain quantitative predictions out of these models. In the empirical arena, we note the lack of connection between most studies and the existing theories described earlier. In both cases, we propose approaches to alleviate these problems. Copyright © 2013 John Wiley & Sons, Ltd.
On‐farm comparison of variable rates of nitrogen with uniform application to maize on canopy reflectance, soil nitrate, and grain yield
Authors: Ma Bao‐Luo , Wu Tian‐Yun , Shang Jiali
Published: November 2013

Recent development in canopy optical‐sensing technology provides the opportunity to apply fertilizer variably at the field scale according to spatial variation in plant growth. A field experiment was conducted in Ottawa, Canada, for two consecutive years to determine the effect of fertilizer nitrogen (N) input at variable‐ vs. uniform‐application strategies at the V6–V8 growth stage, on soil mineral N, canopy reflectance, and grain yield of maize (Zea mays L.). The variable N rates were calculated using an algorithm derived from readings of average normalized difference vegetation index (NDVI) of about 0.8 m × 4.6 m, and N fertilizer was then applied to individual patches of the same size of NDVI readings (0.8 m × 4.6 m) within a plot (2184 m2). Canopy reflectance, expressed as NDVI, was monitored with a hand‐held spectrometer, twice weekly before tasseling and once a week thereafter until physiological maturity. Soil mineral N (0–30 cm depth) was analyzed at the V6 and VT growth stages. Our data show that both variable and uniform‐application strategies for N side‐dressings based on canopy‐reflectance mapping data required less amount of N fertilizer (with an average rate of 80 kg N ha–1 as side‐dressing in addition to 30 kg N ha–1 applied at planting), and produced grain yields similar to and higher nitrogen‐use efficiency (NUE) than the preplant fully fertilized (180 kg N ha–1) treatment. No difference was observed in either grain yield or NUE between the variable‐ and uniform‐application strategies. Compared to unfertilized or fully fertilized treatments, the enhancements in grain yield and NUE of the variable‐rate strategy originated from the later N input as side‐dressing rather than the variation in N rates. The variable‐rate strategy resulted in less spatial variations in soil mineral N at the VT growth stage and greater spatial variations in grain yield at harvest than the uniform‐rate strategy. Both variable‐ and uniform‐application strategies reduced spatial variations in soil mineral N at the VT stage and grain yield compared to the unfertilized treatment. The variable‐rate strategy resulted in more sampling points with high soil mineral N than the uniform‐rate strategy at the VT stage.
Iron‐reducing bacteria can enhance the activation and turnover of the Fe(III)‐fixed phosphorus for mycorrhizal plants
Authors: Zhang Shirong , Wang Rongping , Zhang Lin , Li Shuyi , Feng Gu , Ding Xiaodong
Published: November 2013

In a greenhouse experiment, Medicago sativa was grown in iron‐rich soil colonized with iron‐reducing bacteria (IRB) and/or Glomus mosseae (GM) under different inorganic phosphorus levels, which was to understand the effects of IRB and GM on the activation and turnover of the Fe(III)‐fixed phosphorus. The results showed that at the both P rates, dual‐inoculation treatment stimulated the hyphal growth and increased the shoot P content. IRB could accelerate mycorrhizal colonization, and showed a positive effect on plant biomass and P uptake at both P levels. Compared to sole‐IRB or GM treatment, the dual inoculation treatment increased the soil available P content at both P rates (p < 0.05), which was in the following order: the dual IRB+GM > the sole IRB > the sole GM > control for soil SMP content at low P rate, whilst the dual IRB+GM > the sole IRB ≈ the sole GM > control treatment at high P rate. Compared with the IRB treatment, the GM treatment significantly decreased the soil available P content and the MBP content at low P rate, but made no difference at high P rates. The soil MBC in dual‐inoculation treatment was greatest under the high P level, while the highest soil MBC was the sole‐GM treatment under the low P level. The sole GM treatment showed significantly (p < 0.05) higher soil MBC than that of sole IRB at low P rate (p < 0.05), while there was no significant differences between sole IRB and sole GM at high P rate. Our results suggested that the interaction between GM and IRB had synergetic effect on the mobilization of Fe(III)‐fixed P and their relationship could be regulated by the turnover of MBP. The fact that plants acquired more P via mycorrhizal pathway in the GM‐IRB system suggested that the three symbiont of plant‐GM‐IRB had great ecological and functional significance for P activity in tropical and subtropical soil.
Effects of pretreatment and solution chemistry on solubility of rice‐straw phytoliths
Authors: Ngoc Nguyen Minh , Dultz Stefan , Guggenberger Georg
Published: November 2013

Rice is a Si‐accumulator plant, whereby Si has physio‐chemical functions for plant growth. Its straw contains high shares of plant silica bodies, so‐called phytoliths, and can, when returned to the soil, be an important Si fertilizer. Release of Si from phytoliths into soil solution depends on many factors. In order to improve prognosis of availability and management of Si located in phytoliths, in this study we analyzed the effect of pretreatment of rice straw by dry and wet ashing and the soil‐solution composition on Si release. Dry ashing of rice straw was performed at 400°C, 600°C, and 800°C and wet ashing of the original straw and the sample from 400°C treatment with H2O2. To identify the impact of soil‐solution chemistry, Si release was measured on separated phytoliths in batch experiments at pH 2–10 and in presence of different cations (Na+, K+, Mg2+, Ca2+, Al3+) and anions (Cl–, NO$ _3^- $, SO$ _4^{2-} $, acetate, oxalate, citrate) in the concentration range from 0.1 to 10 mmolc L–1. After burning rice straw at 400°C, phytoliths and biochar were major compounds in the ash. At an electrolyte background of 0.01 molc L–1, Si released at pH 6.5 was one order of magnitude higher than at pH 3, where the zeta potential (ζ) was close to zero. Higher ionic strength tended to suppress Si release. The presence of cations increased ζ, indicating the neutralization of deprotonated Si‐O– sites. Monovalent cations suppressed Si release more strongly than bivalent ones. Neutralization of deprotonated Si‐O– sites by cations might accelerate polymerization, leading to smaller Si release in comparison with absences of electrolytes. Addition of Al3+ resulted in charge reversal, indicating a very strong adsorption of Al3+, and it is likely that Si‐O‐Al‐O‐Si bonds are formed which decrease Si release. The negative effect of anions on Si release in comparison with deionized H2O might be due to an increase in ionic strength. The effect was more pronounced for organic anions than for inorganic ones. Burning of rice straw at low temperatures (e.g., 400°C) appears suitable to provide silicon for rice in short term for the next growing season. High inputs of electrolytes with irrigation water and low pH with concomitant increase of Al3+ in soil solution should be avoided in order to keep dissolution rate of phytoliths at an appropriate level.
A Late Younger Dryas–Early Holocene tephrostratigraphy for Fosen, Central Norway
Authors: LIND EWA M. , WASTEGÅRD STEFAN , LARSEN JEPPE J.
Published: November 2013

A number of rapid climate oscillations occur during the Lateglacial–Early Holocene, 15–8 ka BP period and a well‐developed tephrostratigraphy in association with these oscillations increases the possibilities to correlate climate archives around the North Atlantic. This paper presents a tephrostratigraphy for Fosen peninsula, Central Norway. Both the Vedde Ash ca.12.1 ka BP and the Saksunarvatn Ash ∼10.3 ka BP are important isochrones for correlations of Late Quaternary palaeoenvironmental records in the North Atlantic region and have been assigned ages in GICC05. Beside these tephras we have also identified a new tephra, the Fosen Tephra, with a Borrobol‐type geochemistry that occurs above both the Vedde Ash and the Saksunarvatn Ash with an age ∼10.2 ka BP. Several tephras with Borrobol‐type geochemistry have been identified around the North Atlantic. One group is the Borrobol/Penifiler tephras dated to Greenland Interstadial‐1 and another group is dated to the Early Holocene. We suggest that some of the Early Holocene Borrobol‐type tephras and the Fosen Tephra may actually be the same layer. If so, the Fosen Tephra is spread over a large area of the North Atlantic and has the potential to become an important marker for short‐term climate variability in Scandinavia and in the northern hemisphere.
In vivo optical signatures of neuronal death in a mouse model of Alzheimer's disease
Authors: Lin Alexander J. , Castello Nicholas A. , Lee Grace , Green Kim N. , Durkin Anthony J. , Choi Bernard , LaFerla Frank , Tromberg Bruce J.
Published: November 2013

Background

There currently is a need for cost‐effective, quantitative techniques to evaluate the gradual progression of Alzheimer's disease (AD). Measurement techniques based on diffuse optical spectroscopy can detect blood perfusion and brain cellular composition changes, through measuring the absorption (µa) and reduced scattering (µs′) coefficients, respectively, using non‐ionizing near‐infrared light. Previous work has shown that brain perfusion deficits in an AD mouse model can be detected. The objective of this study was to determine if µs′ is sensitive to the inflammation and neuron death found in AD.

Methods

We used spatial frequency domain imaging (SFDI) to form quantitative maps of µa and µs′ in 3‐month old male CaM/Tet‐DTA mice harboring transgenes for the doxycyline‐regulated neuronal expression of diphtheria toxin. When doxycycline is removed from the diet, CaM/Tet‐DTA mice develop progressive neuronal loss in forebrain neurons. Mice (n = 5) were imaged longitudinally immediately prior to and after 23 days of lesion induction, and µa and µs′ (30 wavelengths, 650–970 nm) were compared to properties obtained from Tet‐DTA controls (n = 5). Neuron death and infiltration of inflammatory cells in brain cortical slices was confirmed with immunohistochemistry.

Results

No significant difference in baseline scattering and absorption were measured between CaM/Tet‐DTA mice and controls. After 23 days of lesion induction, brain cortical µs′ was 11–16% higher in the CaM/Tet‐DTA mice than in controls (P < 0.03). Longitudinal imaging showed no significant difference in µs′ between the first and 23rd day of imaging in controls. Removing doxycycline from the diet was associated with a significant decrease in total hemoglobin concentrations (119 ± 9 µM vs. 91 ± 8 µM) (P < 0.05) in controls, but not in CaM/Tet‐DTA mice.

Conclusions

Neuronal death and brain inflammation are associated with increased tissue scattering (µs′) and this optical biomarker may be useful in pre‐clinical AD therapy evaluation or monitoring of disease progression in AD patients.Lasers Surg. Med. 46:27–33, 2014. © 2013 The Authors. Lasers in Surgery and Medicine Published by Wiley Periodicals, Inc.
On‐Line Monitoring of Molecular Weight Using NIR Spectroscopy in Reactive Extrusion Process
Authors: Bergmann Björn , Becker Wolfgang , Diemert Jan , Elsner Peter
Published: November 2013

Near infrared spectroscopy (NIR) is a versatile tool for process control, scientific research and quality management. Consequently it is our aim to utilize NIR technique for the understanding and following of reactive extrusion processes. As preliminary results it was shown the molecular weight of degraded, non‐purified polyester can be measured and forecasted using purely NIR spectra analysis. In this paper we describe the close correlation of the received molecular weight values of partly glycolised Polyethylene terephthalate (PET) samples using reactive extrusion, measured using size exclusion chromatography (SEC) techniques and chemometric models basing on NIR measurements.
Mass Transfer in Miniemulsion Polymerisation
Authors: Jansen T.G.T. , Lovell P.A. , Meuldijk J. , van Herk A.M.
Published: November 2013

The use of very hydrophobic monomers in heterogeneous polymerisations is restricted because of insufficient mass transfer as a result of limited aqueous phase diffusion. Experimental evidence for a mass transfer mechanism in miniemulsion polymerisation that is based on the direct interaction between droplets as well as between droplets and particles (‘collisions’) rather than monomer diffusion is presented. Mass transfer that results in the formation of a copolymer in the miniemulsion polymerisation of a mixture of lauryl methacrylate and 4‐tert‐butyl styrene, is almost non‐existing when physical contact between individual droplets is prevented by a membrane. However, monomer transport by diffusion is observed in reference experiments with more hydrophilic monomers.
Numerical Simulation of Reactive Extrusion for Polycondensation of Poly(p‐phenylene terephthalamide) (PPTA)
Authors: Tang Hao , Zong Yuan , Xi Zhenhao , Zhao Ling
Published: November 2013

Poly(p‐phenylene terephthalamide) (PPTA), as a typical high performance fiber with excellent strength and modulus property, is usually synthesized by low temperature solution polycondensation with p‐phenylenediamine(PPD) and terephthaloyl chloride(TPC) in twin screw extruders. Since the polycondensation during the process is a multicomponent reaction with high reactivity and wide viscosity range, the molecular weight and its distribution of PPTA are strongly influenced by mixing behavior of the extruder. In this paper, the polycondensation process in fully‐filled conveying elements of twin screw extruder were analyzed by three‐dimensional numerical simulation using the finite element method. The effects of conveying element geometry, rotating speed on mixing state were studied. In order to understand the mechanism behind the reactive extrusion process of PPTA, reaction extent and instantaneous efficiency of stretch in extruder were calculated simultaneously. The results indicate that the reaction process and mixing behavior of the PPTA flow are strongly interrelated. The increase of rotating speed promotes the reaction extent by enhancing the stretch effect, while larger screw pitch accelerates the reaction by rearranges the proportion of energy for stretch.
Models in the Polymer Industry: What Present? What Future?
Authors: Vale H. , Daiss A. , Naeem O. , Šeda L. , Becker K. , Hungenberg K.‐D.
Published: November 2013

An industrial perspective on the present and future role of kinetic and process models in the polymer industry is presented. A number of selected examples illustrate the current value of model‐based approaches in supporting and accelerating tasks like process optimization, product development and design of polymerization reactors. In addition, future trends for the application of models in the polymer industry are discussed and areas where further improvement is thought to be needed are carefully underlined.
Metallocene Catalyzed Ethylene Polymerization with Specially Designed Catalyst Supports and Reaction Systems
Authors: Lee Sangyool , Kim Sung‐Kyoung , Lee Sangbok , Choi Kyu Yong
Published: November 2013

In heterogeneously catalyzed polymerization of α‐olefins, the characteristics of a solid support material impact the catalyst activity, polymer particle morphology, and resulting polymer properties. Silica is the most widely used support for metallocene catalysts in α‐olefin polymerization processes because of its large surface area and favorable surface properties for catalyst anchoring. Understanding the kinetics of heterogeneous olefin polymerization over a solid‐supported catalyst is often quite complicated because of mass transfer effects and catalyst particle fragmentation during the polymerization. Incomplete or premature fragmentation of support material results in a large fraction of catalyst sites left unavailable for the polymerization, causing some inconsistencies in the performance of the catalyst. Silica‐supported metallocene catalysts for α‐olefin polymerization are known to follow the layer‐by‐layer fragmentation mechanism where the fracture of the silica/polymer layer begins from the surface region of a silica particle and it gradually continues into the center of the particle as fragmentation is complete. In this paper, we present new experimental results on ethylene polymerization with rac‐Et(indenyl)2ZrCl2/MAO catalyst using different types of silica supports to quantitatively assess the effects of support geometry on intrinsic catalytic activity. Flat surface silica, nano‐sized spherical silica, straight cylindrical pore silica, and conventional silica are used as supports. The presence or absence of intraparticle monomer diffusion resistance and particle fragmentation has been shown to have significant effects on the catalytic activity.
Micro‐Cellular Polystyrene Foam Preparation Using High Pressure CO2: The Influence of Solvent Residua
Authors: Nistor Andra , Rygl Adam , Bobak Marek , Sajfrtova Marie , Kosek Juraj
Published: November 2013

Polystyrene (PS) foams are commonly used as heat insulators. Their heat insulation properties can be greatly improved by decreasing the cell size into the range of micrometres, resulting in the so‐called micro‐cellular foams. We prepared micro‐cellular PS foams and studied the influence of toluene residua on the foam structure. First, PS films were prepared by the dip‐coating method using toluene as the solvent. Then, the PS films were foamed by the pressure induced foaming method using high pressure CO2. The foam structures were examined by Scanning Electron Microscopy and X‐ray micro‐tomography. For the industrial PS sample containing nucleation agents, the influence of temperature and depressurization rate on cell size was observed in a way consistent with the literature. However, the obtained cell sizes were much larger. Therefore, the effect of toluene residua on the foaming process was systematically studied. A PS sample without nucleation agents was used to exclude their effect on the foaming process. Toluene acts as a co‐solvent and enhances the CO2 solubility in PS, which should lead to a large amount of small cells. However, at toluene concentrations below 8 %wt, the plasticizing effect of toluene dominates, resulting in enhanced coalescence and cell growth. Foam heat insulation properties improve with increasing porosity. The toluene residua increased the porosity by increasing the cell sizes and lowering the thickness of the compact skin at the film surface. We conclude that toluene residua greatly influence the foam structure and this finding can be potentially used to control the foaming process.
Polymerization of N‐Vinyl Formamide in Homogeneous and Heterogeneous Media and Surfactant Free Emulsion Polymerization of MMA Using Polyvinylamine as Stabilizer
Authors: Zataray J. , Aguirre A. , de la Cal J.C. , Leiza J.R.
Published: November 2013

This work considers the homogeneous aqueous phase polymerization of n‐vinyl formamide(NVF). Thus, the effect of temperature, initiator and monomer concentration in the kinetics and molar mass distribution (MMD) of the polyNVF produced was experimentally assessed. SEC‐MALS analysis was misleading because anomalous elution was found due to interaction of the polyNVF chains with the column. This was solved by analyzing the polyNVF by asymmetric‐flow field flow fractionation chromatography coupled with multi‐angle light scattering and differential refractive index, AF4/MALS/RI. The second part of this work considered the synthesis of nanoparticles based on polyNVF. Two routes were explored. In the first one the inverse microemulsion photopolymerization of NVF was attempted and polyNVF dispersions in isopar M with solids content of 18 wt% and particle sizes in the range 50–70 nm with average molar masses of several millions were obtained. In the second route PolyNVF produced in homogeneous aqueous phase was hydrolyzed to yield polyvinyl amine, PVAm. The resulting water soluble polymers were used to produce polymethyl methacrylate, PMMA, nanoparticles by surfactant free emulsion polymerization initiated by tert‐butyl hydroperoxide TBHP. Stable pH responsive PMMA cationic nanoparticles with amino functionalities in the surface were easily produced.
Experimental Investigation of the Morphology Formation of Polymer Particles in an Acoustic Levitator
Authors: Sedelmayer Robert , Griesing Matthias , Halfar Annelie Heide , Pauer Werner , Moritz Hans‐Ulrich
Published: November 2013

Droplet polymerization of N‐vinyl‐2‐pyrrolidone (NVP) and sodium acrylate (NaAA) was carried out in an acoustic levitator for different ambient temperatures and relative humidities. The resulting particle morphologies were compared to particles of two crystalline systems (mannitol and ammonium sulfate) and two disperse systems (silica and styrene ‐ butyl acrylate dispersion), all obtained under similar drying conditions. NVP was found to form a higher amount of crystals with lower temperature and relative humidity, contrary to the behaviour observed for mannitol and ammonium sulfate. The processes of both, polymerization and drying of NaAA lead to similar morphologies at low temperatures and humidities, probably caused by the precipitation of NaAA during polymerization.
Detailed Investigations into Radical Polymerization Kinetics by Highly Time‐Resolved SP–PLP–EPR
Authors: Kattner Hendrik , Buback Michael
Published: November 2013

Instantaneous initiation of radical polymerization by applying an intense laser pulse on a monomer‐photoinitiator solution in conjunction with time‐resolved detection of radical concentration provides access to a detailed picture of polymerization kinetics. Examples are given of measurement of chain‐length‐dependent termination, of intramolecular chain transfer as well as of reversible‐deactivation radical polymerization, namely of RAFT and ATRP. The enormous potential of the method relates to the fact that the kinetics of the major acting species, i.e., of the radicals, may be directly monitored with high time resolution.
Condensed Mode Cooling in Ethylene Polymerisation: Droplet Evaporation
Authors: Alizadeh Arash , McKenna Timothy F.L.
Published: November 2013

A simplified model is used to explore the mechanisms for droplet vaporisation in fluidised bed reactors used for the production of polyethylene in the gas phase. Both homogeneous and heterogeneous vaporisation models are considered. It is shown that for a reasonable range of droplet sizes (less than 1 mm in diameter), droplet vaporisation will be essentially complete at bed heights on the order of 1 m.
Mass moment vector applications to the multi body dynamics with coupled rotations about no intersecting axes
Authors: (Stevanović) Hedrih Katica R. , Stamenković Marija B.
Published: November 2013

Multi body system contains finite number of rigid bodies that are placed on each axis, which do not intersect each other. Derivatives of the linear momentum and angular momentum with respect to time by use mass moment vectors and vector rotators for pole and axis, are determined. A number of theorems are defined. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Asynchronous variational Lie group integration for geometrically exact beam dynamics
Authors: Demoures Francois , Gay‐Balmaz Francois , Leitz Thomas , Leyendecker Sigrid , Ober‐Blöbaum Sina , Ratiu Tudor S.
Published: November 2013

For the elastodynamic simulation of a spatially discretized beam, asynchronous variational integrators (AVI) offer the possibility to use different time steps for every element [1]. They are symplectic and conserve discrete momentum maps and since the presented integrator for geometrically exact beam dynamics [2] is derived in the Lie group setting (SO(3) for the representation of rotational degrees of freedom), it intrinsically preserves the group structure without the need for constraints [3]. A decrease of computational cost is to be expected in situations, where the time steps have to be very low in certain parts of the beam but not everywhere, e.g. if some regions of the beam are moving faster than others. The implementation allows synchronous as well as asynchronous time stepping and shows very good energy behaviour, i.e. there is no drift of the total energy for conservative systems. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Numerical Simulation of Anisotropy Directions in Soft Tissues and in Particular in Skin
Authors: Li Xuhui , Raith Stefan , Itskov Mikhail
Published: November 2013

Orientation of collagen fibers and their spatial distribution predefine macroscopic mechanical properties of the soft tissue and in particular its anisotropy directions. In this contribution, we apply two different procedures to automatically generate these directions for a 3D FE‐model. The first procedure is based on an analogy with a heat conduction problem. Accordingly, a thermal flux under certain temperature boundary conditions is calculated by the same FE model and is further utilized for the definition of the anisotropy directions. The numerical result shows good agreement with Langer's lines data in human skin. Within the second procedure, the fiber vector field is calculated by the Laplacian smoothing method based on the user defined fiber direction sketches. (© 2013 Wiley‐VCH Verlag GmbH & Co. KGaA, Weinheim)