bluuebunny/crossref_metadata_2025 huggingface dataset:
Force Fields for Studying the Structure and Dynamics of Ionic Liquids: A Critical Review of Recent Developments
Authors: Dommert Florian , Wendler Katharina , Berger Robert , Delle Site Luigi , Holm Christian
Published: February 2012

Classical molecular dynamics simulations are a valuable tool to study the mechanisms that dominate the properties of ionic liquids (ILs) on the atomistic and molecular level. However, the basis for any molecular dynamics simulation is an accurate force field describing the effective interactions between all atoms in the IL. Normally this is done by empirical potentials which can be partially derived from quantum mechanical calculations on simple subunits or have been fitted to experimental data. Unfortunately, the number of accurate classical non‐polarizable models for ILs that allow a reasonable description of both dynamical and statical properties is still low. However, the strongly increasing computational power allows one to apply computationally more expensive methods, and even polarizable‐force‐field‐based models on time and length scales long enough to ensure a proper sampling of the phase space. This review attempts to summarize recent achievements and methods in the development of classical force fields for ionic liquids. As this class of salts covers a large number of compounds, we focus our review on imidazolium‐based ionic liquids, but show that the main conclusions are valid for non‐imidazolium salts, too. Insight obtained from recent electronic density functional results into the parametrization of partial charges and on the influence of polarization effects in bulk ILs is highlighted. An overview is given of different available force fields, ranging from the atomistic to the coarse‐grained level, covering implicit as well as explicit modeling of polarization. We show that the recently popular usage of the ion charge as fit parameter can looked upon as treating polarization effects in a mean‐field matter.
Does Corporate Social Responsibility Pay Off in Times of Crisis? An Alternate Perspective on the Relationship between Financial and Corporate Social Performance
Authors: Ducassy Isabelle
Published: February 2012

There are numerous studies analyzing the relationship between corporate social performance (CSP) and financial performance, and even if recent surveys give the upper hand to a generally positive relationship, this question still gives rise to debate. I have chosen to approach this theme from a different angle in order to provide an alternate perspective on this issue: does CSP play a role during periods of uncertainty? I test this hypothesis of CSP acting as an insurance‐like protection on a sample of French listed companies, over several reference periods around the current financial crisis. My findings show a significant positive link between CSP and financial performance for the period corresponding to the beginning of the crisis (second‐half of 2007), but in early 2007 and after the first six months of turmoil, there is no longer a significant connection between the two variables. Copyright © 2012 John Wiley & Sons, Ltd and ERP Environment.
Use of Industrial Waste for the Manufacturing of Sustainable Building Materials
Authors: Sugrañez Rafael , Cruz‐Yusta Manuel , Mármol Isabel , Martín Francisco , Morales Julián , Sánchez Luis
Published: February 2012

Presently, appropriate waste management is one of the main requisites for sustainable development; this task is tackled by the material construction industry. The work described herein is focused on the valorization of granite waste through incorporation, as a filler‐functional admixture, into cement‐based mortar formulations. The main components of the waste are SiO2 (62.1 %), Al2O3 (13.2 %), Fe2O3 (10.1 %), and CaO (4.6 %). The presence of iron oxides is used to develop the photocatalytic properties of the waste. Following heating at 700 °C, α‐Fe2O3 forms in the waste. The inclusion of the heated sample as a filler admixture in a cement‐based mortar is possible. Moreover, this sample exhibits a moderate ability in the photodegradation of organic dye solutions. Also, the plastering mortars, in which the heated samples have been used, show self‐cleaning properties. The preparation of sustainable building materials is demonstrated through the adequate reuse of the granite waste.
Diversity order analysis of orthogonal space–time block coding over keyhole fading channels with antenna selection
Authors: Yang Liang
Published: February 2012

Although there are many research results for the keyhole fading channels in the current literature, fewer results have investigated the antenna selection scheme and quantified the diversity order. In this letter, we first derive some simple statistics of the output signal‐to‐noise ratio for the orthogonal space–time block coding over keyhole fading channels. On the basis of these results, we derive an approximate BER expression for the keyhole MIMO channels with receive antenna selection scheme. Results show that the diversity order with receive antenna selection is min{nR,nT}for nR ≠ nT, which means that the full diversity order with antenna selection is maintained. Finally, numerical results demonstrate the accuracy of our analytical expressions and the tightness of approximate formulas. Copyright © 2012 John Wiley & Sons, Ltd.
Polyphenolic fractions improve the oxidative stability of microencapsulated linseed oil
Authors: Rubilar Mónica , Morales Eduardo , Sáez Roberto , Acevedo Francisca , Palma Barbara , Villarroel Mario , Shene Carolina
Published: February 2012

The main objective of this study was to evaluate the effect of incorporating polyphenolic‐enriched fractions from murta leaves on the oxidative stability of linseed oil microencapsulated by spray drying. For this purpose, polyphenol‐enriched fractions from murta leaves were separated by gel permeation chromatography and chemically characterized. The oxidative stability of microencapsulated linseed oil (MLO) with antioxidants was evaluated in storage conditions at 25°C for 40 days. The antioxidant effects of the polyphenolic fractions and commercial antioxidants (BHT and trolox) on microencapsulated oil were evaluated by the value of conjugated dienes, peroxide, and p‐anisidine. In the initiation step of the oxidation, no significant oxidation delay (p>0.05) in MLO containing fractions F6, F8, or BHT and trolox was observed. However, in the termination step of the oxidation, the addition of fractions F6, F8, and BHT and trolox decreases significantly (p ≤ 0.05) the rancidity in MLO. Furthermore, the results of this study demonstrated the importance of the addition of natural antioxidants such as fractions of murta leaf extract in microencapsulated linseed oil to increase its resistance to oxidation.

Practical applications: For incorporating linseed oil, a source of omega‐3 fatty acids, in the diet it is necessary to protect it against oxidative rancidity, the main cause of deterioration that affects food with a high unsaturated fat content. Microencapsulation is effective in retarding or suppressing the oxidation of unsaturated fatty acids and natural plants extracts are effective in inhibiting the lipid oxidation of microencapsulated oil. The use of process technology and a natural additive is expected to increase storage stability and enable its use in dry foods such as instant products. Linseed oil can be used in human nutrition as well as in animal feed as a replacement for fish oil.
Interaction of Ferrocene Mediators with Gluconobacter oxydans Immobilized Whole Cells and Membrane Fractions in Oxidation of Ethanol
Authors: Indzhgiya E. Yu. , Ponamoreva O. N. , Alferov V. A. , Reshetilov A. N. , Gorton L.
Published: February 2012

Gluconobacter oxydans whole cells and membrane fractions in combination with ferrocene mediators were used to study oxidation of ethanol. The efficiency of mediatorenzyme interaction was assessed by the ratio of maximum current to the apparent Michaelis constant (Imax/KM) for saturating mediator concentrations. The bioelectrocatalytic processes were found to be more efficient with membrane fractions. The highest Imax/KM value of 120 and 3200 µA g/mol for, respectively, cells and fractions was obtained for ferrocene carboxylic acid. In test measurements of biological oxygen demand for rye distillers’ grains, the values obtained by a biosensor based on Gluconobacter membrane fractions and ferrocene were found to correlate with the reference data.
Gold‐Decorated Carbon Composite Electrodes for Enzymatic Oxygen Reduction
Authors: Luckarift Heather R. , Ivnitski Dmitri M. , Lau Carolin , Khripin Constantine , Atanassov Plamen , Johnson Glenn R.
Published: February 2012

Functional composites of carbon and gold nanoparticles create a hierarchical architecture that facilitates high enzyme loading. Subsequent immobilization of the multicopper oxidase, Trametes versciolor laccase, was optimal with dithiobis‐ (succinimidyl propionate), due to the formation of thiol bonds between the protein molecules and gold. The immobilized laccase catalyzed oxygen reduction, with an onset potential of ∼0.6 V (vs. Ag/AgCl), indicated effective orientation of the enzyme redox center to enable direct electron transport between enzyme and the composite electrode. Current densities in half‐cell configurations provide scalable outputs of 50–80 µA/cm2 with the optimized electrode design. The methodology herein describes a rapid, facile preparation of gold‐decorated carbon composite materials for use as electrode scaffolds that can be integrated into a range of bioelectronic devices.
Platinum‐Based and Carbon‐Based Screen Printed Electrodes for the Determination of Benzidine by Differential Pulse Voltammetry
Authors: Falciola Luigi , Pifferi Valentina , Mascheroni Elisabetta
Published: February 2012

Carbon‐ and platinum‐based screen‐printed electrodes have been tested, in comparison with standard GC and Pt electrodes, for detecting benzidine, an organic carcinogenic synthetic compound mainly used as intermediate in production of azo‐dyes. The methodology consists in a DPV in acidic media and offers excellent results in terms of large dynamic concentration ranges, high accuracy and precision and low limits of detection (1.2×10−9 M) and quantification (3.7×10−9 M). The use of disposable electrodes eliminates the problems of fouling and surface regeneration of the device. The use of Nafion membrane to further protect Pt‐SPE from fouling is also discussed. The new methodology was also tested on a real water sample.
Differential effects of diazepam, tandospirone, and paroxetine on plasma brain‐derived neurotrophic factor level under mental stress
Authors: Tamaji Ai , Iwamoto Kunihiro , Kawamura Yukiko , Takahashi Masahiro , Ebe Kazutoshi , Kawano Naoko , Kunimoto Shohko , Aleksic Branko , Noda Yukihiro , Ozaki Norio
Published: February 2012

Objectives

Serum brain‐derived neurotrophic factor (BDNF) levels are reduced in depressed patients, and successful antidepressant treatment leads to increases in BDNF levels. However, little is known about how psychotropic drugs affect the mechanism of the human response to mental stress. We investigated the influence of psychotropic drugs on plasma BDNF levels under mental stress using a driving simulator (DS) task.

Methods

Fourteen healthy male volunteers received one of four drugs, diazepam (5 mg), tandospirone (20 mg), paroxetine (10 mg), and matched placebo, in a double‐blind, crossover manner. Subjects were asked to perform the DS task 4 h post‐dosing. Plasma BDNF levels were measured before and after the DS task.

Results

Plasma BDNF levels under the placebo, diazepam, and tandospirone conditions significantly decreased after the DS task compared with before the task. Conversely, no significant differences in plasma BDNF levels were detected under the paroxetine condition.

Conclusion

As these three psychotropic drugs have differential effects on plasma BDNF levels under mental stress after 4 h post‐dosing, antidepressants, unlike anxiolytics, might have a prompt positive effect on the mental stress response. Copyright © 2012 John Wiley & Sons, Ltd.
How parents make sense of their young children's expressions of everyday pain: A qualitative analysis
Authors: Liossi C. , Noble G. , Franck L.S.
Published: February 2012

Background

Little is known about the communication of everyday pain between young children and their parents, i.e. when children experience pain resulting from minor injury or illness that occur in everyday life. This study aimed to gain an in‐depth understanding of how parents make sense of their young children's expression of everyday pains and how they respond.

Methods

Parents (n = 48) of children (1–5 years inclusive) participated in focus group discussions at seven children's centres across England where they were asked to describe their children's communication of everyday pain. Thematic analysis was used to analyse the data.

Results

Six main themes were identified in the parents' discourse. Parents described children's pain communication as (1) sharing common elements, but unique to each child; (2) having multifaceted pain and non‐pain‐related purposes; (3) challenging to interpret; (4) influenced by their own pain‐related communication; (5) requiring a variety of pharmacological, psychological and physical strategies to manage. The sixth theme that emerged from the data related to parents' dissatisfaction with health care providers, particularly general practitioners' sometimes quick dismissal of parental concerns about their children's pain and illness complaints.

Conclusions

These findings suggest that parents have well developed, although personal, ways of recognizing and responding to their children's communication of pain, but also experience uncertainty in their judgments. Parents would benefit from information about the developmental aspects of pain and should be included as active partners in their children's pain assessment and management.
Different involvement of autophagy in human malignant glioma cell lines undergoing irradiation and temozolomide combined treatments
Authors: Palumbo Silvia , Pirtoli Luigi , Tini Paolo , Cevenini Gabriele , Calderaro Francesco , Toscano Marzia , Miracco Clelia , Comincini Sergio
Published: February 2012

Glioblastoma (GB) has a poor prognosis, despite current multimodality treatment. Beside surgical resection, adjuvant ionizing radiation (IR) combined with Temozolomide (TMZ) drug administration is the standard therapy for GB. This currently combined radio‐chemotherapy treatment resulted in glial tumor cell death induction, whose main molecular death pathways are still not completely deciphered. In this study, the autophagy process was investigated, and in vitro modulated, in two different GB cell lines, T98G and U373MG (known to differ in their radiosensitivity), after IR or combined IR/TMZ treatments. T98G cells showed a high radiosensitivity (especially at low and intermediate doses), associated with autophagy activation, assessed by Beclin‐1 and Atg‐5 expression increase, LC3‐I to LC3‐II conversion and LC3B‐GFP accumulation in autophagosomes of irradiated cells; differently, U373MG cells resulted less radiosensitive. Autophagy inhibition, using siRNA against BECN1 or ATG‐7 genes, totally prevented decrease in viability after both IR and IR/TMZ treatments in the radiosensitive T98G cells, confirming the autophagy involvement in the cytotoxicity of these cells after the current GB treatment, contrary to U373MG cells. However, rapamycin‐mediated autophagy, that further radiosensitized T98G, was able to promote radiosensitivty also in U373MG cells, suggesting a role of autophagy process in enhancing radiosensitivity. Taken together, these results might enforce the concept that autophagy‐associated cell death might constitute a possible adjuvant therapeutic strategy to enhance the conventional GB treatment. J. Cell. Biochem. 113: 2308–2318, 2012. © 2012 Wiley Periodicals, Inc.
Involvement of hnRNP A1 in the matrix metalloprotease‐3‐dependent regulation of Rac1 pre‐mRNA splicing
Authors: Pelisch Federico , Khauv Davitte , Risso Guillermo , Stallings‐Mann Melody , Blaustein Matías , Quadrana Leandro , Radisky Derek C. , Srebrow Anabella
Published: February 2012

Rac1b is an alternatively spliced isoform of the small GTPase Rac1 that includes the 57‐nucleotide exon 3b. Rac1b was originally identified through its over‐expression in breast and colorectal cancer cells, and has subsequently been implicated as a key player in a number of different oncogenic signaling pathways, including tumorigenic transformation of mammary epithelial cells exposed to matrix metalloproteinase‐3 (MMP‐3). Although many of the cellular consequences of Rac1b activity have been recently described, the molecular mechanism by which MMP‐3 treatment leads to Rac1b induction has not been defined. Here we use proteomic methods to identify heterogeneous nuclear ribonucleoprotein (hnRNP) A1 as a factor involved in Rac1 splicing regulation. We find that hnRNP A1 binds to Rac1 exon 3b in mouse mammary epithelial cells, repressing its inclusion into mature mRNA. We also find that exposure of cells to MMP‐3 leads to release of hnRNP A1 from exon 3b and the consequent generation of Rac1b. Finally, we analyze normal breast tissue and breast cancer biopsies, and identify an inverse correlation between expression of hnRNP A1 and Rac1b, suggesting the existence of this regulatory axis in vivo. These results provide new insights on how extracellular signals regulate alternative splicing, contributing to cellular transformation and development of breast cancer. J. Cell. Biochem. 113: 2319–2329, 2012. © 2012 Wiley Periodicals, Inc.
Conjugated circuits currents in hexabenzocoronene and its derivatives formed by joining proximal carbons
Authors: Randić Milan , Vukičević Damir , Balaban Alexandru T. , Vračko Marjan , Plavšić Dejan
Published: February 2012

We report on calculated CC bond currents for a dozen derivatives of hexabenzocoroenene in which one or more proximal carbon atoms at the molecular periphery have been bridged. The approach that we use is graph‐theoretical in nature, following our outline of this method in 2003, which is based on finding all conjugated circuits in all Kekulé valence structures of these molecules. To the π‐electrons having 4n + 2 π‐electrons are assigned anticlockwise π‐electron currents and to conjugated circuits having 4n π‐electrons are assigned π‐electron currents. One may summarize the results reported in this work by stating that CC bond currents in the compounds considered decrease on going from peripheral rings to the central ring of the molecule, and also that CC bond currents decrease by insertion of bridges to proximal peripheral benzenoid rings. © 2012 Wiley Periodicals, Inc.
Metronidazole photodegradation in aqueous solution by using photosensitizers and hydrogen peroxide
Authors: Sánchez‐Polo Manuel , Rivera‐Utrilla José , Prados‐Joya Gonzalo , Ocampo‐Pérez Raúl
Published: February 2012

BACKGROUND: The effectiveness of UV radiation on the indirect photodegradation of metronidazole (MNZ) conducting a kinetic study of the process in the presence of radical promoter (H2O2) and photosensitizer (Sens) promoters (duroquinone, tetrahydroxyquinone, tetrachloro‐1,4‐benzoquinone, 4‐carboxy‐benzophenone, 2,4‐dihydroxybenzophenone, 4‐hydroxybenzophenone, and 4,4′‐dihydroxybenzophenone) was investigated.

RESULTS: The electron‐donating groups of photosensitizers may favor MNZ photodegradation through electron transfer. However, the photosensitizers studied showed low effectiveness of MNZ photodegradation in aqueous phase. The presence of H2O2 substantially increased MNZ photodegradation rate, which was enhanced by increasing the concentration of hydrogen peroxide in the system. The contribution of direct photolysis of MNZ in the UV/H2O2 system was drastically decreased with increasing H2O2 concentrations.

CONCLUSIONS: The low effectiveness obtained with most of the Sens used demonstrates that metronidazole cannot be photoxidized by indirect photooxidation in aqueous solution. Copyright © 2012 Society of Chemical Industry
Linear models for estimating annual and growing season reference evapotranspiration using averages of weather variables
Authors: Cristea Nicoleta C. , Kampf Stephanie K. , Burges Stephen J.
Published: February 2012

We develop linear regression equations to estimate location‐specific average annual reference evapotranspiration (ETo) using one or more of annual averages of: incoming solar radiation (Rs), air temperature (T), relative humidity (RH), and wind speed (U). We also provide two sets of equations to estimate growing season ETo, either using one or more of annual averages of Rs, T, RH, and U, or using growing season averages of the same variables. The equations are developed using the FAO‐56 Penman–Monteith model ETo estimates as a reference. Supporting weather data to develop the regression equations were from 102 locations (494 station‐years) across the contiguous United States. The models were tested with additional data from 32 stations (114 station‐years). To illustrate potential applications of the regression models, we estimate spatial patterns of annual ETo and growing season ETo across the contiguous United States using existing spatial datasets of annual averages of Rs, T, RH, and U. Other applications of the models provided may include rapid assessments of historical annual and growing season ETo, evaluation of past ETo trends, or evaluation of ETo projected trends based on output from global climate models. Copyright © 2012 Royal Meteorological Society
Metabolism of ferulic acid during growth of Lactobacillus plantarum and Lactobacillus collinoides
Authors: Knockaert Dries , Raes Katleen , Wille Christophe , Struijs Karin , Van Camp John
Published: February 2012

BACKGROUND: Food‐isolated lactic acid bacteria can transform ferulic acid (FA) into several products. Since quantification of these metabolites during the different bacterial growth phases is lacking, the aim of this study was to identify and quantify conversion products of FA and to follow the kinetics of FA metabolism during growth of Lactobacillus plantarum and Lactobacillus collinoides.

RESULTS: Lactobacillus plantarum and Lactobacillus collinoides were incubated in MRS broth, to which different amounts of FA were added (final concentrations of 0, 0.5, 1.5 and 3 mmol L−1), at 30 °C until the late stationary phase. Lactobacillus plantarum metabolised FA into 4‐vinylguaiacol (4‐VG) and hydroferulic acid (HFA). Conversion to 4‐VG started simultaneously with the degradation of FA, while formation of HFA started in the mid‐exponential phase. Lactobacillus collinoides only formed 4‐VG, mainly in the stationary phase. No significant effect of the different amounts of FA was seen on the growth and fermentation characteristics of both bacteria.

CONCLUSION: The results demonstrate that both bacteria are able to convert FA. However, start of conversion differs between the two strains. The different amounts of FA had no influence on the growth and fermentation characteristics of both bacteria. Copyright © 2012 Society of Chemical Industry
The in vitro digestibility and absorption of magnesium in some edible seaweeds
Authors: Nakamura Eri , Yokota Hiroki , Matsui Tohru
Published: February 2012

BACKGROUND: Many edible seaweeds are rich in magnesium (Mg). However, Mg absorption is low in some seaweeds because fibers in these seaweeds suppress Mg absorption. We hypothesize that Mg absorption from some other seaweeds is not low because of the diversity of fibers. We measured Mg concentration and Mg solubility after in vitro digestion in edible seaweeds, Aosa (Ulvaceae pertusa), Kombu (Laminaria japonica) and Funori (Gloiopeltis furcata). Then we determined Mg absorption in rats given diets containing these seaweeds or magnesium oxide as the major source of Mg, and calculated Mg absorption from seaweeds.

RESULTS: The fractional apparent absorption of Mg in seaweeds was Kombu = magnesium oxide > Aosa = Funori. Mg concentration was Aosa > Kombu and Funori had an intermediate amount of Mg, while Mg solubility after in vitro digestion was Funori = Kombu > Aosa. Consequently, the absorbable Mg concentration was Aosa = Kombu > Funori.

CONCLUSION: The absorption of Mg from different seaweeds differs and is not affected by the Mg solubility alone. The absorbable Mg concentration was high in Aosa and in Kombu, indicating that Aosa and Kombu are good sources of Mg. Copyright © 2012 Society of Chemical Industry
Combined effects of E2F1 and E2F2 polymorphisms on risk and early onset of squamous cell carcinoma of the head and neck
Authors: Lu Meixia , Liu Zhensheng , Yu Hongping , Wang Li‐E , Li Guojun , Sturgis Erich M. , Johnson David G. , Wei Qingyi
Published: February 2012

Deregulated expression of most members of the E2F family has been detected in many human cancers. We examined the association of common single nucleotide polymorphisms (SNPs) of E2F transcription factors 1 and 2 (E2F1 and E2F2) with risk of squamous cell carcinoma of the head and neck (SCCHN) in 1,096 SCCHN patients and 1,090 cancer‐free controls. We genotyped 10 selected SNPs in E2F1 and E2F2, including those at the near 5′‐untranslated region (UTR), microRNA (miRNA)‐binding sites at the near 3′‐UTR and tagSNPs according to bioinformatics analysis. Although none of the selected SNPs alone was significantly associated with risk of SCCHN, there was a statistically significantly increased risk of SCCHN associated with the combined risk genotypes (i.e., rs3213182 AA, rs3213183 GG, rs3213180 GG, rs321318121 GG, rs2742976 GT+TT, rs6667575 GA+AA, rs3218203 CC, rs3218148 AA, rs3218211 CC, and rs3218123 GT+TT). Compared with those with 0–4 risk genotypes, an increased risk was observed for those who carried 5–8 risk genotypes (adjusted OR = 1.04; 95% CI = 0.86–1.26) and 9–10 risk genotypes (adjusted OR = 1.62; 95% CI = 1.14–2.30) in a dose–response manner (P = 0.045). Furthermore, the joint effect was more pronounced among patients with oropharyngeal cancer, younger adults (≤57 yr old), men, non‐smokers, non‐drinkers, and individuals with family history of cancer in first‐degree relatives. Additionally, we also observed that those with 5–10 risk genotypes had an earlier SCCHN onset than those with 0–4 risk genotypes, particularly for non‐smokers and/or non‐drinkers. We concluded that E2F1 and E2F2 genetic variants may jointly play important roles in head and neck carcinogenesis. © 2012 Wiley Periodicals, Inc.
Identification of the thermal growth characteristics of coagulated tumor tissue in laser‐induced thermotherapy
Authors: Hömberg Dietmar , Liu Jijun , Togobytska Nataliya
Published: February 2012

We consider an inverse problem arising in laser‐induced thermotherapy, a minimally invasive method for cancer treatment, in which cancer tissues are destroyed by coagulation. For the dosage planning, numerical simulations play an important role. To this end, a crucial problem is to identify the thermal growth kinetics of the coagulated zone. Mathematically, this problem is a nonlinear and nonlocal parabolic heat source inverse problem. The solution to this inverse problem is defined as the minimizer of a nonconvex cost functional in this paper. The existence of the minimizer is proven. We derive the Gateaux derivative of the cost functional, which is based on the adjoint system, and use it for a numerical approximation of the optimal coefficient. Numerical implementations are presented to show the validity of the optimization schemes. Copyright © 2012 John Wiley & Sons, Ltd.
Study of 5‐hydroxymethylfurfural and its metabolite 5‐sulfooxymethylfurfural on induction of colonic aberrant crypt foci in wild‐type mice and transgenic mice expressing human sulfotransferases 1A1 and 1A2
Authors: Florian Simone , Bauer‐Marinovic Morana , Taugner Felicitas , Dobbernack Gisela , Monien Bernhard H. , Meinl Walter , Glatt Hansruedi
Published: February 2012

Scope

It was reported that the Maillard product 5‐hydroxymethylfurfural (HMF) initiates and promotes aberrant crypt foci (ACF) in rat colon. We studied whether 5‐sulfooxymethylfurfural (SMF), an electrophilic and mutagenic metabolite of HMF, is able to induce ACF in two murine models.

Methods and results

In the first model, FVB/N mice received four intraperitoneal administrations of SMF (62.5 or 125 mg/kg) or azoxymethane (10 mg/kg). Animals were killed 4–40 weeks after the last treatment. A total of 1064 ACF and five adenocarcinomas were detected in the azoxymethane‐treated groups (20 animals), but none in the negative control and SMF‐treated groups (35 and 50 animals, respectively). In the second model, HMF was administered via drinking water to wild‐type FVB/N mice and transgenic mice carrying several copies of human sulfotransferase (SULT) 1A1 and 1A2 genes. HMF SULT activity was clearly elevated in cytosolic fractions of colon mucosa, liver and kidney of transgenic animals compared to wild‐type mice and humans. The animals (six per group) received 134 and 536 mg HMF/kg/day for 12 weeks. HMF did not induce any ACF either in wild‐type or transgenic animals.

Conclusion

We found no evidence for an induction of ACF by HMF or its metabolite SMF in extensive studies in mice.
Determination of liquefaction susceptibility of soil: a least square support vector machine approach
Authors: Samui Pijush , Karthikeyan J.
Published: February 2012

This article adopts least square support vector machine (LSSVM) for determination of liquefactions susceptibility of soil based on standard penetration test data. Two models (Models I and II) have been developed. For Model I, input variables are cyclic stress ratio and standard penetration test value (N). Model II employs peak ground acceleration and N as input variables. The developed LSSVM models (Models I and II) give equations for determination of liquefaction susceptibility of soil. The performances of Models I and II are the same. The developed LSSVM gives probabilistic output. The results of LSSVM have been compared with the artificial neural network model. This article shows that N and the peak ground acceleration are sufficient input parameters for determination of liquefaction susceptibility of soil. Copyright © 2012 John Wiley & Sons, Ltd.
Korrelative Licht‐ und Elektronenmikroskopie (CLEM)
Authors: Elli Alexandra F. , Thomas Christian , Böker Christian , Wiederspahn Markus
Published: February 2012

Korrelative Mikroskopie bezeichnet die Verknüpfung von unterschiedlichen Mikroskopietechniken, sowohl gerätetechnisch als auch auf der Bildebene. Die Kombination verschiedener Verfahren an ein und derselben Probenstelle erlaubt einen zusätzlichen Informationsgewinn, da verschiedene, sich ergänzende Informationen räumlich zugeordnet und unterschiedliche Größenordnungen bezogen auf Auflösung und Bildfeld erfasst werden können. Automatisierte Systeme gewähren außerdem einen entscheidenden Zeitvorteil bei der Untersuchung.
Bilder berechnen – nicht nur aufnehmen
Authors: Fehr Janis , Jähne Bernd
Published: February 2012

Das noch junge Forschungsgebiet der „Computational Photography”︁ besetzt die Schnittstelle zwischen technischer Optik, Computer Graphik, Bildverarbeitung und Bildanalyse. Grundlegendes Ziel ist, mittels algorithmischer („computation”︁) Ansätze die physikalischen Grenzen der traditionellen projektiven Kamera, wie begrenzte Tiefenschärfe, Auflösung und Verlust der dritten Dimension, zu überwinden. In diesem Tutorial wird zuerst der neue Ansatz des Computational Imaging erläutert und dann exemplarisch einige dieser neuen, zum Teil bereits kommerziell verfügbaren, „Computational”︁‐Kameras vorgestellt und deren Anwendung im Bereich der industriellen Bildverarbeitung diskutiert.
Use of nonsteroidal anti‐inflammatory drugs prior to chronic renal replacement therapy initiation: a nationwide study
Authors: Kristensen Søren Lund , Fosbøl Emil L. , Kamper Anne‐Lise , Køber Lars , Hommel Kristine , Lamberts Morten , Abildstrøm Steen Z. , Blicher Thalia M. , Torp‐Pedersen Christian , Gislason Gunnar H.
Published: February 2012

Purpose

Nonsteroidal anti‐inflammatory drugs (NSAIDs) may be associated with severe renal complications, including acute renal failure, reduced glomerular filtration rate and interstitial nephritis. Caution against NSAIDs is therefore recommended in advanced chronic kidney disease. In this study, we examined NSAID use, aetiology and comorbidity among a national cohort of patients before the initiation of chronic renal replacement therapy (RRT).

Methods

Patients initiated on chronic RRT in the period 1997–2006 were identified in the Danish National Registry on Regular Dialysis and Transplantation, including etiological diagnosis. The use of NSAID before the start of RRT was studied by linkage to the National Prescription Register and comorbidity by linkage to the National Patient Registry.

Results

A total of 6663 patients were included in the study, and 2407 patients (36.1%) were prescribed NSAID in the 3 years before the start of RRT. These patients were older (mean age = 63.0 vs 61.4 years) and had a significantly higher degree of comorbidity (Charlson score = 2.85 vs 2.61, p < 0.05) compared with patients not treated with NSAIDs. In the 3 years leading up to RRT, the number of patients treated with NSAID each year and the cumulated median length of treatment including all NSAIDs were stable at approximately 20% and 40 days, respectively.

Conclusions

In this study of a nationwide group of patients, we observed a widespread use of NSAID with an unaffected high annual incidence in the 3 years leading up to the initiation of RRT. Copyright © 2012 John Wiley & Sons, Ltd.
Enhanced orientation of the water‐assisted injection‐molded ipp in the presence of nucleating agent
Authors: Zheng Guo‐Qiang , Jia Zhenhua , Liu Xianhu , Liu Baochen , Zhang Xiaoli , Dai Kun , Shao Chunguang , Zheng Xuejing , Liu Chuntai , Cao Wei , Chen Jingbo , Peng Xiangfang , Li Qian , Shen Changyu
Published: February 2012

The nucleated isotactic polypropylene (iPP) was molded by water‐assisted injection molding. The crystalline morphology and orientation distribution were studied. The results show that shear brought by melt filling and pressurized water penetration can separately induce the formation of oriented structures in skin region (i.e., the region near mold cavity wall) and the water channel region. For virgin iPP, slightly oriented lamellae appear exclusively in the above aforementioned regions. However, shish‐kebab structure occurs not only in skin and water channel region of the iPP containing moderate content of nucleator (0.2 wt%) but also in the whole region of the iPP containing a higher content of nucleator (1 wt%). It is well known that nucleator cannot directly induce the development of shish‐kebab in the absence of shear, thus the results indicate: shear flow actually distributes over a much broader range than expected; in shear field, nucleator is significantly helpful for the shear which is not sufficient to solely induce oriented structure to promote the formation of the oriented structure. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Dynamic gray‐box modeling for on‐line monitoring of polymer extrusion viscosity
Authors: Liu Xueqin , Li Kang , McAfee Marion , Nguyen Bao Kha , McNally Gerard M.
Published: February 2012

Melt viscosity is a key indicator of product quality in polymer extrusion processes. However, real time monitoring and control of viscosity is difficult to achieve. In this article, a novel “soft sensor” approach based on dynamic gray‐box modeling is proposed. The soft sensor involves a nonlinear finite impulse response model with adaptable linear parameters for real‐time prediction of the melt viscosity based on the process inputs; the model output is then used as an input of a model with a simple‐fixed structure to predict the barrel pressure which can be measured online. Finally, the predicted pressure is compared to the measured value and the corresponding error is used as a feedback signal to correct the viscosity estimate. This novel feedback structure enables the online adaptability of the viscosity model in response to modeling errors and disturbances, hence producing a reliable viscosity estimate. The experimental results on different material/die/extruder confirm the effectiveness of the proposed “soft sensor” method based on dynamic gray‐box modeling for real‐time monitoring and control of polymer extrusion processes. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Anhydrous proton conductivity and chemical oxidation stability of amphoteric N‐methyl‐5‐vinyltetrazole‐based copolymers
Authors: Ye Sheng , Pu Hongting , Wan Decheng
Published: February 2012

Poly(N‐methyl‐5‐vinyltetrazole‐co‐5‐vinyltetrazole) (P(MVT‐VT)) with different N‐methyl‐5‐vinyltetrazole (MVT) contents was synthesized via the method of click chemistry and the methylation thereafter. The chemical structure of the copolymers was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR). Compared with that of poly(5‐vinyltetrazole) (PVT), the solubility of P(MVT‐VT) is improved. The chemical oxidation stability of the copolymer increases with increasing substitution value of the methyl group on the tetrazole ring. H3PO4 and imidazole (Imi) blended PVT and P(MVT‐VT) composite membranes were prepared. The proton conductivity of P(MVT‐VT)/H3PO4 and P(MVT‐VT)/Imi composite membranes decreases with increasing MVT content. After the methylation of the tetrazole ring, the amphoteric properties of P(MVT‐VT) is improved, which means either acid or base blended P(MVT‐VT) can exhibit suitable proton conductivity. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers
Synthesis and photovoltaic properties of two side‐chain polymeric metal complexes containing 8‐hydroxyquinoline and fluorene units with Zn(II) and Cd(II)
Authors: Wen Gaojun , Zhang Lirong , Guo Lihui , Xiu Qian , Deng Jinyan , Zhong Chaofan
Published: February 2012

Two novel side‐chain polymeric metal complexes (PF1 and PF2) containing 8‐hydroxyquinoline and fluorene units with Zn(II) and Cd(II) having donor‐acceptor π‐conjugated structure have been synthesized and characterized using Fourier transform infrared, 1H NMR, UV‐visible and photoluminescence spectroscopies, thermogravimetric analysis, differential scanning calorimetry, elemental analysis and cyclic voltammetry. Dye‐sensitized solar cells (DSSCs) based on PF1 and PF2 as the dye sensitizers exhibit good device performance with solar‐to‐electricity conversion efficiency up to 0.32% (Jsc = 0.83 mA cm−2, Voc = 0.62 mV and FF = 0.62) and 0.24% (Jsc = 0.69 mA cm−2, Voc = 0.59 mV and FF = 0.60), respectively, under simulated AM 1.5 G solar irradiation (100 mW cm−2). The data show that these novel polymeric metal complexes are suitable for DSSCs. Copyright © 2012 Society of Chemical Industry
Initiated PECVD of Organosilicon Coatings: A New Strategy to Enhance Monomer Structure Retention
Authors: Coclite Anna Maria , Gleason Karen K.
Published: February 2012

A new deposition method, initiated PECVD (iPECVD), is proposed for the formation of organosilicon polymers with enhanced monomer structure retention compared to conventional PECVD. The quasi‐selective fragmentation of an initiator is driven by a low power plasma discharge, as opposed to using a hot filament for initiator decomposition as in a standard, plasma‐free initiated CVD (iCVD). The weak peroxide bond (OO) in the initiator permits the formation of radical species at very low plasma power density (0.07 W · cm−2). Kinetic analysis of the deposition process indicates that the film formation rate follows the Arrhenius law, similarly to other iCVD process from organosilicon monomers.

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On the unyielding hydrophobic core of villin headpiece
Authors: Brown Jeffrey W. , Farelli Jeremiah D. , McKnight C. James
Published: February 2012

Villin headpiece (HP67) is a small, autonomously‐folding domain that has become a model system for understanding the fundamental tenets governing protein folding. In this communication, we explore the role that Leu61 plays in the structure and stability of the construct. Deletion of Leu61 results in a completely unfolded protein that cannot be expressed in Escherichia coli. Omission of only the aliphatic leucine side chain (HP67 L61G) perturbed neither the backbone conformation nor the orientation of local hydrophobic side chains. As a result, a large, solvent‐exposed hydrophobic pocket, a negative replica of the leucine side‐chain, was created on the surface. The loss of the hydrophobic interface between leucine 61 and the hydrophobic pocket destabilized the construct by ∼3.3 kcal/mol. Insertion of a single glycine residue immediately before Leu61 (HP67 L61[GL]) was also highly destabilizing and had the effect of altering the backbone conformation (α‐helix to π‐helix) in order to precisely preserve the wild‐type position and conformation of all hydrophobic residues, including Leu61. In addition to demonstrating that the hydrophobic side‐chain of Leu61 is critically important for the stability of villin headpiece, our results are consistent with the notion that the precise interactions present within the hydrophobic core, rather than the hydrogen bonds that define the secondary structure, specify a protein's fold.
Risk criteria, protection layers, and conditional modifiers
Authors: Summers Angela E. , Hearn William H.
Published: February 2012

Risk analysis assesses the likelihood and consequence of events. The acceptability of the identified risk is determined by comparing it to a specified risk tolerance. The criteria applied depend on the analysis boundary, which may be the hazardous event or extend to the harm posed by the hazardous event. Risk analyses generally begin with a determination of the likelihood that the hazardous event occurs. This is where the process deviation exceeds the safe operating limit of the process resulting in loss of containment, release of hazardous materials, or other undesirable consequence. These analyses require estimation of the likelihood that the initiating event occurs and the probability that the proactive protection layers do not operate as required, allowing the hazardous event to occur. Reactive protection layers and conditional modifiers are considered when the analysis is evaluating the likelihood that harm is caused by the hazardous event.

Various methods for performing risk analyses are discussed in several CCPS publications including Chemical Process Quantitative Risk Analysis [CCPS/AIChE, Guidelines for Chemical Process Quantitative Risk Analysis, 2000], Hazard Evaluation Procedures [CCPS/AIChE, Guidelines for Hazard Evaluation Procedures, 2008], and Layers of Protection Analysis [CCPS/AIChE, Layer of Protection Analysis: Simplified Process Risk Assessment, 2001]. However, the link between the selected risk criteria as described in Guidelines for Developing Quantitative Safety Risk Criteria [CCPS/AIChE, Guidelines for Developing Quantitative Safety Risk Criteria, 2009] and the factors considered in the analysis is not clearly described in these texts. Recognizing this opportunity, this article begins with a brief introduction to risk analysis concepts to provide a foundation for a discussion of the typical analysis boundaries and associated risk criteria. Then, it discusses how the analysis boundary and risk criteria affect the consideration of protection layers, enabling conditions, and conditional modifiers. © 2011 American Institute of Chemical Engineers Process Saf Prog, 2011
Growth and spectroscopy of single lateral InGaAs/GaAs quantum dot molecules
Authors: Heldmaier Matthias , Hermannstädter Claus , Witzany Marcus , Wang Lijuan , Peng Jie , Rastelli Armando , Bester Gabriel , Schmidt Oliver G. , Michler Peter
Published: February 2012

Laterally coupled quantum dot molecules (QDMs) were grown by molecular beam epitaxy. We describe the challenging growth process as well as morphological studies of the produced samples leading to a promising theoretical approach to describe the properties of the QDMs using a many‐body pseudopotential approach. Extensive spectroscopic measurements on these laterally coupled QDMs were performed. We prove the single quantum system nature of the considered QDMs by photon‐correlation measurements and analyze the photoluminescence (PL) and photoluminescence excitation (PLE) spectra under different aspects. The spectroscopic results are compared in detail to the performed theoretical calculations. Agreement between experiment and theory are presented, as well as, limitations of the model as indicated by most recent measurements.

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Atomic‐force microscopy (AFM) image of a lateral QDM.
Excellent organic/inorganic transparent thin film moisture barrier entirely made by hot wire CVD at 100 °C
Authors: Spee Diederick , van der Werf Karine , Rath Jatin , Schropp Ruud
Published: February 2012

We present a silicon nitride/polymer hybrid multilayer moisture barrier for flexible electronics made entirely by hot wire chemical vapor deposition (HWCVD) at substrate temperatures below 100 °C. Using the initiated CVD (iCVD) variant of HWCVD for the polymer layers, these can be extremely thin, while efficiently decoupling the defects in consecutive inorganic layers. Although a single layer of low temperature SiNx is more prone to have pinholes than its state‐of‐the‐art high temperature equivalent, we have achieved a simple three‐layer structure consisting of two low‐temperature SiNx layers with a polymer layer in between, which is pinhole free and shows a water vapor transmission rate (WVTR) as low as 5 × 10–6 g/m2/day at a temperature of 60 °C and a relative humidity of 90%. This WVTR is low enough for organic devices. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
An undecomposed approach to control design for a class of nonlinear descriptor systems
Authors: Sun Liying , Wang Yuzhen
Published: February 2012

This paper studies control designs for a class of nonlinear descriptor systems under state undecomposed status and presents a number of new results on the stabilization, H∞ control, and robust adaptive control. It is shown that under a suitable state feedback, two sufficient conditions of impulse‐free can be established for the resulted closed‐loop system. Using the established conditions, the stabilization problem is then discussed for the nonlinear descriptor system, and a stabilization control design procedure is presented; on the basis of which, an admissible H∞ controller and an admissible robust adaptive controller are designed for the system with external disturbances and/or parametric uncertainties. Simulation results on a nonlinear descriptor circuit system show the efficiency of the controllers proposed in this paper. Copyright © 2012 John Wiley & Sons, Ltd.
Unmatched uncertainties compensation based on high‐order sliding mode observation
Authors: de Loza Alejandra Ferreira , Bejarano Francisco J. , Fridman Leonid
Published: February 2012

The problem of compensation of the effects of unmatched uncertainties ∕ perturbations is considered. High‐order sliding mode observers are employed for exact state and uncertainties ∕ perturbations reconstruction. A sliding mode control design is proposed ensuring theoretically exact compensation of the uncertainties ∕ perturbations for the corresponding unmatched states based on the identified perturbation values. An inverted pendulum simulation example is considered illustrating the feasibility of the proposed approach.Copyright © 2012 John Wiley & Sons, Ltd.