bluuebunny/crossref_metadata_2025 huggingface dataset:
Diffusion‐controlled radiochemical oxidation of bisphenol A polysulfone
Authors: Richaud Emmanuel , Colin Xavier , Monchy‐Leroy Carole , Audouin Ludmila , Verdu Jacques
Published: November 2010

The radiochemical degradation of bisphenol A polysulfone was investigated under a γ‐ray dose rate of 24 kGy h−1 up to 30.7 MGy total absorbed dose at 60 °C using gel permeation chromatography, sol–gel analysis, glass transition and rheometry measurements, and oxidation profile measurements by microscopy coupled with Fourier transform infrared analysis in attenuated total reflectance mode. Thin (200 µm) and thick (2 mm) samples were compared. Thin samples undergo mainly chain scissions whereas thick ones undergo mainly crosslinking. The thickness of oxidized layers and, radiochemical yields for chain scissions, crosslinking, oxygen absorption and radical formation were tentatively determined from experimental data in order to determine the influence of oxidative processes on radiochemical ageing and to establish the nature of the crosslinking reactions. Copyright © 2010 Society of Chemical Industry
Synthesis of rosin‐based imidoamine‐type curing agents and curing behavior with epoxy resin
Authors: Wang Honghua , Wang Haiwei , Zhou Guangyuan
Published: November 2010

Rosin is an abundantly available natural product. The characteristic fused ring structure of rosin acids is analogous to that of some aromatic compounds in rigidity, and makes rosin and its derivatives potential substitutes for those aromatic compounds. In the study reported, the synthesis of biobased curing agents containing imide structure using rosin and the cure reaction were investigated. Rosin‐based imidoamine‐type curing agents were synthesized, and the chemical structure was confirmed using 1H NMR, Fourier transform infrared and electrospray ionization spectroscopy. The curing behavior with diglycidyl ether of bisphenol A epoxy was studied using differential scanning calorimetry. The thermal mechanical properties and thermal stability of the cured epoxy resins were evaluated using dynamic mechanical analysis and thermogravimetry, respectively. The results indicate that the curing behavior of the rosin‐based curing agents is similar to that of curing agents with analogous structures. Cured products have good thermal stability due to the presence of the imide group and the bulky hydrogenated phenanthrene ring structure. Rosin acids have a great potential in the synthesis of epoxy curing agents as replacements for some of the current commercial aromatic or cycloaliphatic analogues. Copyright © 2010 Society of Chemical Industry
Novel poly(thiourea‐ether‐imide)s derived from 4,4′‐oxydiphenyl‐bis(thiourea): probing the possibility for high‐temperature applications
Authors: Kausar Ayesha , Zulfiqar Sonia , Ali Liaquat , Ishaq Muhammad , Ilyas Sarwar Muhammad
Published: November 2010

Our interest in the fabrication of high‐performance polyimides has led to thiourea‐substituted poly(thiourea‐ether‐imide)s (PTEIs) with good retention of thermal properties along with flame retardancy. A new aromatic monomer, 4,4′‐oxydiphenyl‐bis(thiourea) (ODPBT), was efficiently synthesized and polymerized with various dianhydrides (pyromellitic dianhydride, 3,3′,4,4′‐benzophenonetetracarboxylic dianhydride and 4,4′‐(hexafluoroisopropylidene)diphthalic dianhydride) via two‐stage chemical imidization to fabricate a series of PTEIs. The structural characterization of ODPBT and the polymers was carried out using Fourier transform infrared, 1H NMR and 13C NMR spectral techniques along with crystallinity, organosolubility, inherent viscosity and gel permeation chromatographic measurements. PTEIs bearing CS and Omoieties in the backbone demonstrated an amorphous nature and were readily soluble in various amide solvents. The novel polymers had inherent viscosities of 1.16–1.23 dL g−1 and molecular weights of ca 90 783–96 927 g mol−1. Their thermal stability was substantiated via 10% weight loss in the temperature range 516–530 °C under inert atmosphere. The polyimides had glass transition temperatures of 260–265 °C. Incorporation of thiourea functionalities into polymer backbones is demonstrated to be an effective way to enhance their thermal properties and flame retardancy. Thus, ODPBT can be considered as an excellent candidate for use in the synthesis of high‐performance polymeric materials. Copyright © 2010 Society of Chemical Industry
Life‐cycle greenhouse gas effects of introducing nano‐crystalline materials in thin‐film silicon solar cells
Authors: van der Meulen Rob , Alsema Erik
Published: November 2010

Solar PV is widely considered as a “green” technology. This paper, however, investigates the environmental impact of the production of solar modules made from thin‐film silicon. We focus on novel applications of nano‐crystalline Silicon materials (nc‐Si) into current amorphous Silicon (a‐Si) devices. Two nc‐Si specific details concerning the environmental performance can be identified, when we want to compare to a‐Si modules. First, in how far the extra (and thicker) silicon layer (s) affects upstream material requirements and energy use. Second, in how far depositing an extra silicon layer may increase emissions of greenhouse gases as additional emissions of Fluor gases (F‐gases) are associated to this step. The much larger global warming potential of F‐gases (17 200–22 800 times that of CO2) may lead to higher environmental burdens. To date, no study has yet analyzed the effect of F‐gas usage on the environmental profile of thin‐film silicon solar modules. We performed a life‐cycle assessment (LCA) to investigate the current environmental usefulness of pursuing this novel micromorph concept. The switch to the new micromorph technology will result in a 60–85% increase in greenhouse gas emissions (per generated kWh solar electricity) in case of NF3 based clean processing, and 15–100% when SF6 is used. We conclude that F‐gas usage has a substantial environmental impact on both module types, in particular the micromorph one. Also, micromorph module efficiencies need to be improved from the current 8–9% (stabilized efficiency) toward 12–16% (stab. eff.) in order to compensate for the increased environmental impacts. Copyright © 2010 John Wiley & Sons, Ltd.
Radiation induced oxidation of hydroxy indoles by NO and Br radicals: effect of pH
Authors: Gaikwad P. , Naik G. H. , Priyadarsini K. I. , Mohan H. , Rao B. S. M.
Published: November 2010

The reactions of NOand Brradicals with 5‐hydroxyindole (HIn), 5‐hydroxytryptophol (HTpl), 5‐hydroxytryptophan (HTpn) and 5‐hydroxytryptamine (HTpe) were studied using pulse radiolysis. The rate constants for their reaction with NOradical were found to vary from 105to 107 dm3 mol−1 s−1in the pH range 5–9 but a higher value (k = 1.4 ± 0.01 × 108 dm3 mol−1 s−1) was noticed in HTpe at pH 9. The gradual increase in reactivity with pH is due to the decrease in the reduction potentials of indoloxyl radicals withE = 0.55 V at pH 9. In contrast, the rate constants with Brradical were found to be diffusion controlled and remained unaffected by the pH. The transient spectra measured are attributed to the indoloxyl radical formed on oxidation withλmaxat 420 nm. The indoloxyl radicals further react with the parent hydroxy indole derivative forming the radical adduct and their decay was found to be pH dependent in derivatives containing an amino group. At pH 5, no decay of the radical adducts was seen in all derivatives up to 5 ms whereas those with the amino group decayed faster at pH 9. The total yields of the oxygen centred and carbon centred radicals formed in the reaction of NOradical with hydroxy indoles were found to be nearly equal to G(NO). Our results suggest that NOradical is inefficient in oxidizing hydroxy indoles under physiological conditions preventing the formation of toxic dimers of indole derivatives. Copyright © 2010 John Wiley & Sons, Ltd.
Conformational analysis of N‐phenyl‐ and N‐trifyl‐4,4‐dimethyl‐4‐silathiane 1‐sulfimides
Authors: Shainyan Bagrat A. , Suslova Elena N. , Kleinpeter Erich
Published: November 2010

N‐Substituted 4,4‐dimethyl‐4‐silathiane 1‐sulfimides [R = Ph (1), CF3 (2)] were studied experimentally by variable temperature dynamic NMR spectroscopy. Low temperature 13C NMR spectra of the two compounds revealed the frozen ring inversion process and approximately equal content of the axial and equatorial conformers. Calculations of the 4‐silathiane derivatives 1, 2 and the model compound [R = Me (3)] as well as their carbon analogs, the similarly N‐substituted thiane 1‐sulfimides [R = Ph (4), CF3 (5), Me (6)] at the DFT/B3LYP/6–311G(d,p) level in the gas phase and in chloroform solution using the PCM model at the same level of theory showed a strong dependence of the relative stability of the conformer on the solvent. The electronegative trifluoromethyl group increases the relative stability of the axial conformer. Copyright © 2010 John Wiley & Sons, Ltd.
Enhanced Autohesive Bonding of Polyetheretherketone (PEEK) for Biomedical Applications Using a Methane/Oxygen Plasma Treatment
Authors: Awaja Firas , Zhang Shengnan , James Natalie , McKenzie David R.
Published: November 2010

High performance polymers such as PEEK are currently considered unsuitable for the encapsulation of biomedical implants, partly because of a lack of a strong and durable bonding technology. Strong autohesive bonds were achieved between semi‐crystalline PEEK surfaces using a treatment in RF plasma with a mixture of methane and oxygen (CH4/O2) gases. The surfaces were bonded under pressure above the glass transition temperature (Tg) and below the melting point (Tm). The treatment with CH4/O2 gases produced significantly higher bond strength than untreated samples and samples treated with CH4 only. The CH4/O2 plasma treatments generated a higher polar component of surface energy than observed for the untreated surfaces and also higher than that observed for surfaces plasma treated in CH4 alone. XPS analysis of surfaces treated with CH4/O2 plasma for more than 3 min showed that oxygenated nano‐films were deposited that contained CO groups and these showed the highest bonding strength. Free radical induced cross‐linking of the deposited nano‐film is proposed as a mechanism to explain the high bond strength achieved.

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Chemical and Morphological Characterization of Low‐k Dielectric Films Deposited From Hexamethyldisiloxane and Ethylene RF Glow Discharges
Authors: Coclite Anna Maria , Milella Antonella , Palumbo Fabio , Fracassi Francesco , d'Agostino Riccardo
Published: November 2010

Low‐k dielectric films were deposited by PECVD from mixtures of hexamethyldisiloxane (HMDSO), ethylene, and oxygen. After deposition the films were thermally annealed in order to reduce their permittivity. Different deposition conditions were investigated in order to accomplish the best trade‐off between low permittivity and low thickness loss upon annealing. Soft plasma conditions were required in order to allow organic species incorporation in the film and achieve dielectric constant as low as 2.2 with a thickness loss of 14% upon thermal annealing treatment. Results were also compared to those obtained with divinyltetramethyldisiloxane, which is similar in structure to HMDSO but with two vinyl groups replacing methyl ones. The morphological analysis showed that feeding the plasma with a large amount of ethylene, CHx‐enriched nanodomains were obtained over a siloxane matrix. Finally, the plasma phase composition was also investigated by infrared spectroscopy and correlated with the film chemistry.

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Characterising metabolic resistance in pyrethroid‐insensitive pollen beetle (Meligethes aeneus F.) from Poland and Switzerland
Authors: Philippou Despina , Field Linda M , Wȩgorek Pawel , Zamojska Joanna , Andrews Melanie C , Slater Russell , Moores Graham D
Published: November 2010

BACKGROUND: Pollen beetle (Meligethes aeneus F.) has become the most important pest of oilseed rape in Europe, but its control has been greatly hindered by pyrethroid resistance. Target‐site resistance has been implicated previously, and, whilst synergism has been found with piperonyl butoxide (PBO), the exact nature of metabolic resistance has remained unknown. The use of PBO, in conjunction with its analogue EN 16/5‐1, has allowed the characterisation of metabolic resistance.

RESULTS: In vitro assays in combination with in vivo studies using PBO and EN 16/5‐1 showed that high synergism of pyrethroids was primarily correlated with an oxidative mechanism, although a limited contribution by esterases was implicated in one population.

CONCLUSION: Differential synergism has enabled the characterisation of pyrethroid resistance in populations of M. aeneus. It was found to be principally due to an oxidative‐based mechanism, and, if a synergist were to be used to inhibit this enzyme group, renewed control against resistant pests could be achieved. Copyright © 2010 Society of Chemical Industry
Synthesis of D‐glucosamine quaternary ammonium derivatives and evaluation of their antifungal activity together with aminodeoxyglucose derivatives against two wood fungi Coriolus versicolor and Poria placenta: structure–activity relationships
Authors: Muhizi Théoneste , Coma Véronique , Grelier Stéphane
Published: November 2010

BACKGROUND: Structure–activity relationships are often reported in scientific studies. These may be employed in searching for new acceptable biocides to use against harmful microorganisms, because the biocides used hitherto encounter various problems, including lack of efficiency, high toxicity and persistence. Nowadays, scientists are trying to find new, environmentally acceptable biocides to replace these earlier biocides. Different compounds from renewable materials have been studied and have shown pronounced antifungal activity against wood fungi. These include aminopolysaccharide derivatives and different quaternary ammonium polymers. A biological study carried out with these products indicated a possible relationship between amino groups and differences in biological activity observed.

RESULTS: In this study, an amino group was successively fixed to different carbon atoms of glucose, and glucosamine was also modified by both N‐alkylation and quaternisation. The impact of the amino group position on antifungal activity against two wood decay fungi was investigated. The amino group at the anomeric position showed the highest antifungal activity against both Coriolus versicolor Quel. and Poria placenta (Fr.) Cooke. Furthermore, the positive impact of both N‐alkylation and quaternisation on the growth of both strains was demonstrated.

CONCLUSION: The anomeric position of the amino group and the N‐alkylation and quaternisation of amino sugars considerably increase the antifungal activity of these compounds. Copyright © 2010 Society of Chemical Industry
Immobilisation of bifenthrin for termite control
Authors: Guan Yan‐Qing , Chen Jia Mei , Li Zhi Bin , Feng Qi Li , Liu Jun‐Ming
Published: November 2010

BACKGROUND: Termites are worldwide pests causing considerable damage to agriculture, forestry and buildings. While various approaches have been tried to eliminate termite populations, the relevant toxicants are associated with certain risks to the environment and human health.

RESULTS: In this study, to combine the merits of effective chemical control by bifenthrin and a drug photoimmobilisation technique, silk fibroin was used as a carrier to embed bifenthrin, which was then photoactively immobilised by ultraviolet treatment on the surface of wood (cellulose). The immobilised bifenthrin embedded in the photoactive silk fibroin was characterised by Fourier transform infrared spectroscopy (FTIR), ultraviolet absorption spectroscopy (UV), fluorescence measurement and CHN analysis. The surface structures and biological activity were examined by scanning electron microscopy (SEM), atomic force microscopy (AFM), electron spectroscopy for chemical analysis (ESCA) and bioassays respectively.

CONCLUSIONS: The results indicate that the embedded and immobilised bifenthrin has been very well protected from free release and has a long‐term stability allowing slow release with a high efficiency against termites at a low dose of 1.25 µg cm−2. This study provides a novel and environmentally benign technique for termite control by photoimmobilising silk‐fibroin‐embedded bifenthrin on the surface of materials that are otherwise easily attacked by termites. Copyright © 2010 Society of Chemical Industry
Effect of pesticide fate parameters and their uncertainty on the selection of ‘worst‐case’ scenarios of pesticide leaching to groundwater
Authors: Vanderborght Jan , Tiktak Aaldrik , Boesten Jos JTI , Vereecken Harry
Published: November 2010

BACKGROUND: For the registration of pesticides in the European Union, model simulations for worst‐case scenarios are used to demonstrate that leaching concentrations to groundwater do not exceed a critical threshold. A worst‐case scenario is a combination of soil and climate properties for which predicted leaching concentrations are higher than a certain percentile of the spatial concentration distribution within a region. The derivation of scenarios is complicated by uncertainty about soil and pesticide fate parameters. As the ranking of climate and soil property combinations according to predicted leaching concentrations is different for different pesticides, the worst‐case scenario for one pesticide may misrepresent the worst case for another pesticide, which leads to ‘scenario uncertainty’.

RESULTS: Pesticide fate parameter uncertainty led to higher concentrations in the higher percentiles of spatial concentration distributions, especially for distributions in smaller and more homogeneous regions. The effect of pesticide fate parameter uncertainty on the spatial concentration distribution was small when compared with the uncertainty of local concentration predictions and with the scenario uncertainty.

CONCLUSION: Uncertainty in pesticide fate parameters and scenario uncertainty can be accounted for using higher percentiles of spatial concentration distributions and considering a range of pesticides for the scenario selection. Copyright © 2010 Society of Chemical Industry
Assessing departure from dose linearity under a repeated measures incomplete block design
Authors: Cheng Bin , Chow Shein‐Chung
Published: November 2010

Dose proportionality/linearity is a desirable property in pharmacokinetic studies. Various methods have been proposed for its assessment. When dose proportionality is not established, it is of interest to evaluate the degree of departure from dose linearity. In this paper, we propose a measure of departure from dose linearity and derive an asymptotic test under a repeated measures incomplete block design using a slope approach. Simulation studies show that the proposed method has a satisfactory small sample performance in terms of size and power. Copyright © 2010 John Wiley & Sons, Ltd.
Dietary quinic acid supplied as the nutritional supplement AIO + AC‐11® leads to induction of micromolar levels of nicotinamide and tryptophan in the urine
Authors: Pero Ronald W. , Lund Harald
Published: November 2010

Hippuric acid is synthesized and produced primarily by the gastrointestinal (GI) microflora. However, there is no known health benefit for hippuric acid except its catabolic conjugation of benzene‐type compounds via glycine and subsequent excretion in the urine. For years the GI tract microflora were known to metabolize quinic acid to hippuric acid. Recently it was also proposed that DNA repair was strongly enhanced by quinic acid. In order to explain these quinic acid effects, Pero and colleagues have examined whether tryptophan and nicotinamide were also enhanced by quinic acid levels in urine. They were indeed, and so another study was designed using a natural supplement source of quinic acid called AIO + AC‐11®, and then the effects of intervention were measured after only 21 days. It was possible to show profound increases in quinic acid that were again paralleled by increases in tryptophan and nicotinamide urinary levels. Because the high pressure liquid chromatography (HPLC) methods differed greatly between the two studies, differences in chemical analyses probably did not contribute to the data base. Copyright © 2010 John Wiley & Sons, Ltd.
Flexible Field Emission of Nitrogen‐Doped Carbon Nanotubes/Reduced Graphene Hybrid Films
Authors: Lee Duck Hyun , Lee Jin Ah , Lee Won Jong , Kim Sang Ouk
Published: November 2010

The outstanding flexible field emission properties of carbon hybrid films made of vertically aligned N‐doped carbon nanotubes grown on mechanically compliant reduced graphene films are demonstrated. The bottom‐reduced graphene film substrate enables the conformal coating of the hybrid film on flexible device geometry and ensures robust mechanical and electrical contact even in a highly deformed state. The field emission properties are precisely examined in terms of the control of the bending radius, the N‐doping level, and the length or wall‐number of the carbon nanotubes and analyzed with electric field simulations. This high‐performance flexible carbon field emitter is potentially useful for diverse, flexible field emission devices.
Fluorescent Polymeric Nanoparticles: Aggregation and Phase Behavior of Pyrene and Amphotericin B Molecules in Nanoparticle Cores
Authors: Kumar Varun , Adamson Douglas H. , Prud’homme Robert K.
Published: November 2010

The state of aggregation of compounds, especially drugs, in the cores of nanoparticles (NPs) formed by rapid precipitation is a significant unresolved issue. The state can control the dissolution kinetics from the NP, bioavailability, and chemical stability of the compound. A block‐copolymer‐directed rapid precipitation process is used to form ≈100 nm NPs comprising mixtures of hydrophobic species including fluorescent probe molecules. Fluorescence measurements are used to probe the state of aggregation and dynamics of rearrangement of pyrene (Py), Hostasol Yellow (HosY), and amphotericin B (AmpB) in NP cores. The Flory–Huggins theory of mixing is used to predict the miscibility or phase separation of the fluorophores from the host NP core material (polystyrene, cholesterol, or polycaprolactone). For Py, excimer fluorescence shows an initial microphase separation in the polystyrene core. Over time the Py redistributes more uniformly with a decrease in excimer and increase in monomer fluorescence. The Flory–Huggins theory predicts the miscibility. For HosY, the fluorescence quenching is not time‐dependent, thus indicating stability of the microphase‐separated fluorophores, which is consistent with the Flory–Huggins theory calculations. For the drug compound AmpB, the amphiphilic character of the molecule creates unusual “anti‐Ostwald” ripening behavior in which the size distribution decreases and narrows over time, and the fluorescence demonstrates an increased ordering in the NP core over time—opposite to the behavior observed for Py.
Inhibition of Influenza Virus Infection by Multivalent Sialic‐Acid‐Functionalized Gold Nanoparticles
Authors: Papp Ilona , Sieben Christian , Ludwig Kai , Roskamp Meike , Böttcher Christoph , Schlecht Sabine , Herrmann Andreas , Haag Rainer
Published: November 2010

An efficient synthesis of sialic‐acid‐terminated glycerol dendron to chemically functionalize 2 nm and 14 nm gold nanoparticles (AuNPs) is described. These nanoparticles are highly stable and show high activity towards the inhibition of influenza virus infection. As the binding of the viral fusion protein hemagglutinin to the host cell surface is mediated by sialic acid receptors, a multivalent interaction with sialic‐acid‐functionalized AuNPs is expected to competitively inhibit viral infection. Electron microscopy techniques and biochemical analysis show a high binding affinity of the 14 nm AuNPs to hemagglutinin on the virus surface and, less efficiently, to isolated hemagglutinin. The functionalized AuNPs are nontoxic to the cells under the conditions studied. This approach allows a new type of molecular‐imaging activity‐correlation and is of particular relevance for further application in alternative antiviral therapy.
Graphene Fluoride: A Stable Stoichiometric Graphene Derivative and its Chemical Conversion to Graphene
Authors: Zbořil Radek , Karlický František , Bourlinos Athanasios B. , Steriotis Theodore A. , Stubos Athanasios K. , Georgakilas Vasilios , Šafářová Klára , Jančík Dalibor , Trapalis Christos , Otyepka Michal
Published: November 2010

Stoichoimetric graphene fluoride monolayers are obtained in a single step by the liquid‐phase exfoliation of graphite fluoride with sulfolane. Comparative quantum‐mechanical calculations reveal that graphene fluoride is the most thermodynamically stable of five studied hypothetical graphene derivatives; graphane, graphene fluoride, bromide, chloride, and iodide. The graphene fluoride is transformed into graphene via graphene iodide, a spontaneously decomposing intermediate. The calculated bandgaps of graphene halides vary from zero for graphene bromide to 3.1 eV for graphene fluoride. It is possible to design the electronic properties of such two‐dimensional crystals.
Flexible electronics: 12‐GHz Thin‐Film Transistors on Transferrable Silicon Nanomembranes for High‐Performance Flexible Electronics (Small 22/2010)
Authors: Sun Lei , Qin Guoxuan , Seo Jung‐Hun , Celler George K. , Zhou Weidong , Ma Zhenqiang
Published: November 2010

Multigigahertz flexible electronics are attractive and have broad applications. A gate‐after‐source/drain fabrication process using preselectively doped single‐crystal silicon nanomembranes (SiNM) is an effective approach to realizing high device speed. However, further downscaling this approach has become difficult in lithography alignment. In this full paper, a local alignment scheme in combination with more accurate SiNM transfer measures for minimizing alignment errors is reported. By realizing 1 μm channel alignment for the SiNMs on a soft plastic substrate, thin‐film transistors with a record speed of 12 GHz maximum oscillation frequency are demonstrated. These results indicate the great potential of properly processed SiNMs for high‐performance flexible electronics.
Attentional blink and repetition blindness
Authors: Arnell Karen M. , Shapiro Kimron L.
Published: November 2010

When two masked, to‐be‐attended targets are presented within half a second of each other, report accuracy for the second target (T2) is impaired relative to when the two targets are presented farther apart in time or relative to when the first target (T1) can be ignored. This effect is known as the attentional blink (AB). An additional T2 accuracy deficit is observed if T1 and T2 are identical or highly similar on a task‐relevant dimension. This effect is known as repetition blindness (RB). For both AB and RB, targets are typically imbedded in rapid serial visual presentation (RSVP) streams and the dual‐task attention cost lasts approximately half a second. Given the high degree of superficial similarity, AB and RB are often considered to be related phenomena. Although research thus far has suggested that both phenomena reflect limits of the attentional system and how attention is allocated when needing to organize stimuli for entrance into awareness, these two phenomena are dissociable; RB is not simply an enhanced AB. Furthermore, investigations of AB and RB have taken quite different courses over the last two decades. The AB has been investigated extensively with a variety of experimental, behavioral, neurophysiological, and clinical approaches, and has become widely used as a paradigm of convenience with which to study other effects. In contrast, studies of RB have tended to manipulate the nature of the target information to understand the level of representation that supports RB. WIREs Cogni Sci 2011 2 336–344 DOI: 10.1002/wcs.129

This article is categorized under:

Psychology > Attention
Antibiotics that target protein synthesis
Authors: McCoy Lisa S. , Xie Yun , Tor Yitzhak
Published: November 2010

The key role of the bacterial ribosome makes it an important target for antibacterial agents. Indeed, a large number of clinically useful antibiotics target this complex translational ribonucleoprotein machinery. The majority of these compounds, mostly of natural origin, bind to one of the three key ribosomal sites: the decoding (or A‐site) on the 30S, the peptidyl transferase center (PTC) on the 50S, and the peptide exit tunnel on the 50S. Antibiotics that bind the A‐site, such as the aminoglycosides, interfere with codon recognition and translocation. Peptide bond formation is inhibited when small molecules like oxazolidinones bind at the PTC. Finally, macrolides tend to block the growth of the amino acid chain at the peptide exit tunnel. In this article, the major classes of antibiotics that target the bacterial ribosome are discussed and classified according to their respective target. Notably, most antibiotics solely interact with the RNA components of the bacterial ribosome.

The surge seen in the appearance of resistant bacteria has not been met by a parallel development of effective and broad‐spectrum new antibiotics, as evident by the introduction of only two novel classes of antibiotics, the oxazolidinones and lipopeptides, in the past decades. Nevertheless, this significant health threat has revitalized the search for new antibacterial agents and novel targets. High resolution structural data of many ribosome‐bound antibiotics provide unprecedented insight into their molecular contacts and mode of action and inspire the design and synthesis of new candidate drugs that target this fascinating molecular machine.WIREs RNA2011 2 209–232 DOI: 10.1002/wrna.60

This article is categorized under:

RNA Interactions with Proteins and Other Molecules > Small Molecule–RNA Interactions

Translation > Ribosome Structure/Function
Assessment of Quality of Life After Gastrectomy Using EORTC QLQ‐C30 and STO22
Authors: Kobayashi Daisuke , Kodera Yasuhiro , Fujiwara Michitaka , Koike Masahiko , Nakayama Goro , Nakao Akimasa
Published: November 2010

Background

The European Organization for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire–Cancer (QLQ‐C30) and the site‐specific module for gastric cancer (QLQ‐STO22) have seldom been used to measure the postoperative health‐related quality of life (HRQOL) in Japanese gastric cancer patients. The aim of this study was to evaluate the HRQOL after gastrectomy using these instruments and to compare various aspects of HRQOL among surgical procedures.

Methods

A total of 98 patients who underwent gastrectomy and had no recurrence were evaluated. Among them, we compared the differences between major surgical procedures consisting of open total gastrectomy (TG, n = 8), open distal gastrectomy (DG, n = 24), and laparoscopy‐assisted distal gastrectomy (LADG, n = 44). Questionnaires were completed at baseline and at 1, 3, 6 and 12 months postoperatively.

Results

The worst scores for most of the items were observed at 1 month after surgery and usually improved thereafter. Scores after TG were the worst of all surgical procedures across all dimensions throughout the period. Scores after LADG were generally superior to those after DG at 1 and 3 months postoperatively but not at 12 months.

Conclusions

EORTC QLQ‐C30 and STO22 detected differences in several aspects of HRQOL among patients treated by the three surgical procedures. The laparoscopic approach resulted in superior short‐term outcomes, whereas TG continued to affect the HRQOL in several items 12 months after surgery.
Challenges of Meeting Surgical Needs in the Developing World
Authors: Gosselin Richard A. , Gyamfi Yaw‐Adu , Contini Sandro
Published: November 2010

The burden of surgical conditions and diseases is increasing in low‐income and middle‐income countries, but the capacity to meet the demands they present is not following pace. Ongoing initiatives, such as brief visits by surgeons from advantaged countries, sending surgical residents to spend time in a developing country as part of their training, or ships weighing anchor offshore and offering some limited on‐shore or on‐board services, have not proven successful. More comprehensive and sustainable solutions include the development of local training programs, better retention of trainees with adequate incentives particularly in rural areas, and engaging government and professional associations, as well as academic institutions, to develop and implement policies to address local training needs.
The effect of methylene blue during orthotopic liver transplantation on post reperfusion syndrome and postoperative graft function
Authors: Fukazawa Kyota , Pretto Ernesto A.
Published: November 2010

Background/Purpose

In orthotopic liver transplantation (OLT), a major component of the post‐reperfusion syndrome is hypotension, which may lead to additional graft liver ischemia‐reperfusion injury. A proposed mechanism of reperfusion hypotension is the massive induction of oxidative stress triggering the release of pro‐inflammatory mediators, including nitric oxide (NO). Methylene blue (MB) is an inhibitor of inducible NO synthase and an NO scavenger that has been shown to attenuate reperfusion hypotension. Of note, recent reports have shown that the exogenous administration of NO during OLT significantly improved the recovery of the graft liver. Therefore, we sought to investigate the effects of MB on the functional recovery of the graft liver following OLT.

Methods

We analyzed retrospective data from 715 patients who underwent OLT between 2003 and 2008. We classified patients into those who received a 1–1.5 mg/kg intravenous bolus of MB immediately prior to reperfusion (MB group) and those who did not (control group). Propensity score matching was used to adjust for differences between patients who received intraoperative MB and those who did not, and these data were used to determine the association between a single MB bolus during OLT and postoperative graft dysfunction.

Results

Our study cohort consisted of 715 OLT patients, of whom 105 received MB and 610 did not. After propensity score matching, demographic and donor data were similar in the two groups, except for the older age of recipients in the MB group (55.5 ± 0.9 vs 53.1 ± 0.8 years,p= 0.026). No differences were seen in mean arterial pressure changes after reperfusion and no differences were found in vasopressor requirements (bolus or infusion) or transfusion requirements. In addition, there was no significant difference in the incidence of primary nonfunction, retransplantation within 60 days, acute rejection, or graft survival between the groups by multivariate analysis or Kaplan–Meier survival analysis.

Conclusions

In our study, the administration of MB at 1–1.5 mg/kg immediately prior to reperfusion did not prevent post‐reperfusion hypotension and did not decrease vasopressor usage or transfusion requirements after reperfusion. Also, MB did not have any impact on postoperative graft function. These findings may argue against the routine use of MB during OLT.
Enzymology of the branched‐chain amino acid oxidation disorders: the valine pathway
Authors: Wanders Ronald J. A. , Duran Marinus , Loupatty Ference J.
Published: November 2010

Valine is one of the three branched‐chain amino acids which undergoes oxidation within mitochondria. In this paper, we describe the current state of knowledge with respect to the enzymology of the valine oxidation pathway and the different disorders affecting oxidation.
New insights on diet variability revealed by DNA barcoding and high‐throughput pyrosequencing: chamois diet in autumn as a case study
Authors: Rayé Gilles , Miquel Christian , Coissac Eric , Redjadj Claire , Loison Anne , Taberlet Pierre
Published: November 2010

Characterizing the diet of large herbivores and the determinants of its variation remains a difficult task in wild species. DNA‐based techniques have the potential to complement traditional time‐consuming methods based on the microhistology of plant cuticle fragments in fecal or rumen samples. Recently, it has been shown that a short chloroplast DNA fragment, the P6 loop of the trnL (UAA) intron, can act as a minimalist barcode. Here, we used the trnL approach with high‐throughput pyrosequencing to study diet from feces in a wild herbivore, the alpine chamois (Rupicapra rupicapra) and showed that the fine resolution in plant determination obtained with this method allows exploring subtle temporal shifts and inter‐individual variability in diet composition. First, we built a DNA barcoding database of 475 plants species. Seventy‐two percent of plant species can be unambiguously identified to species level, 79% to genus level and 100% to family level using the P6 loop. Second, we analysed 74 feces collected from October to November. Based on 47,896 P6 loop sequences, we identified a total of 110 taxa, 96 in October and 76 in November, with a clear diet shift between October and November. We recognized four and two clusters of feces composition in October and November, respectively, revealing different diet categories among individuals within each month. DNA‐based diet analysis is faster and more taxonomically precise than studies based on microhistology, and opens new possibilities for analysing plant‐herbivore interactions in the wild.
Modeling the Primary Oxidation in Commercial Fish Oil Preparations
Authors: Sullivan Jenna C. , Budge Suzanne M. , St‐Onge Marc
Published: November 2010

The quality of commercial fish oil products can be difficult to maintain because of the rapid lipid oxidation attributable to the high number of polyunsaturated fatty acids (PUFA), specifically eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). While it is known that oxidation in fish oil is generally the result of a direct interaction with oxygen and fatty acid radicals, there are very few studies that investigate the oxidation kinetics of fish oil supplements. This study uses hydroperoxides, a primary oxidation product, to model the oxidation kinetics of two commercially available fish oil supplements with different EPA and DHA contents. Pseudo first order kinetics were assumed, and rate constants were determined for temperatures between 4 and 60 °C. This data was fit to the Arrhenius model, and activation energies (Ea) were determined for each sample. Both Ea agreed with values found in the literature, with the lower PUFA sample having a lower Ea. The oil with a lower PUFA content fit the first‐order kinetics model at temperatures ≥20 °C and ≤40 °C, while the higher PUFA oil demonstrated first‐order kinetics at temperatures ≥4 °C and ≤40 °C. When the temperature was raised to 60 °C, the model no longer applied. This indicates that accelerated testing of fish oil should be conducted at temperatures ≤40 °C.
Pseudohypoparathyreoidismus und epigenetische Veränderungen des GNAS-Genlocus
Authors: Thiele S. , Hiort O.
Published: November 2010

Die Bezeichnung Pseudohypoparathyreoidismus (PHP) beschreibt eine heterogene Gruppe von Erkrankungen, die durch eine Endorganresistenz gegenüber Parathormon (PTH) gekennzeichnet sind. Sie werden durch eine Defizienz der α-Untereinheit stimulierender G-Proteine (Gsα) verursacht. Gsα ist essenziell für die Signalvermittlung durch extrazelluläre Liganden über mehr als 1000 verschiedene G-Protein-gekoppelte Rezeptoren in das Zellinnere. Durch eine gewebespezifische Prägung verursachen maternale, autosomal-dominant vererbte Mutationen in dem für Gsα kodierenden GNAS-Genlocus PTH-Resistenz und klinische Zeichen der hereditären Albright-Osteodystrophie (AHO), einschließlich Brachymetakarpie, Kleinwuchs, subkutaner Ossifikationen und mentaler Retardierung (PHP-Typ Ia). Paternal vererbte GNAS-Mutationen führen zu selektiven AHO-Zeichen ohne Parathormonresistenz (Pseudo-PHP). Der PHP-Typ Ib, bei dem eine isolierte PTH-Resistenz vorliegt, wird durch heterozygote, maternal vererbte Deletionen stromaufwärts vom oder innerhalb des GNAS-Locus hervorgerufen, die durch eine Störung des Imprintingmusters eine gewebespezifische Stilllegung der Gsα-Expression hervorrufen. Diese Patienten zeigen in der Regel keine Zeichen der AHO. In der vorliegenden Arbeit wird ein Überblick über die Rolle epigenetischer Faktoren bei der Ätiopathogenese verschiedener PHP-Formen gegeben.
When Distance Mattered: Geographic Scale and the Development of European Representative Assemblies
Authors: STASAVAGE DAVID
Published: November 2010

Scholars investigating European state development have long placed a heavy emphasis on the role played by representative institutions. The presence of an active representative assembly, it is argued, allowed citizens and rulers to contract over raising revenue and accessing credit. It may also have had implications for economic growth. These arguments have in turn been used to draw broad implications about the causal effect of analogous institutions in other places and during other time periods. But if assemblies had such clear efficiency benefits, why did they not become a universal phenomenon in Europe prior to the nineteenth century? I argue that in an era of costly communications and transport, an intensive form of political representative was much easier to sustain in geographically compact polities. This simple fact had important implications for the pattern of European state formation, and it may provide one reason why small states were able to survive despite threats from much larger neighbors. I test several relevant hypotheses using an original data set that provides the first broad view of European representative institutions in the medieval and early modern eras. I combine this with a geographic information system data set of state boundaries and populations in Europe between 1250 and 1750. The results suggest a strong effect of geographic scale on the format of political representation. The broader implication of this result is to provide a reminder that if institutions help solve contracting problems, ultimately, the maintenance of institutions may itself depend on ongoing transactions costs.
The effect of feeding modified soyabean oil enriched with C18 : 4n-3 to broilers on the deposition ofn-3 fatty acids in chicken meat
Authors: Rymer C. , Hartnell G. F. , Givens D. I.
Published: November 2010

Supplementing broiler diets with conventional vegetable oils has little effect on the long-chainn-3 PUFA (LCn-3 PUFA) content of the meat. The present study investigated the effect on fatty acid composition and sensory characteristics of chicken meat when broilers were fed oil extracted from soyabeans (SDASOY) that had been genetically engineered to produce C18 : 4n-3 (stearidonic acid (SDA), 240 mg/g oil). Three diets were fed to 120 birds (eight replicate pens of five birds) from 15 d to slaughter (41–50 d). Diets were identical apart from the oil added to them (45 and 50 g/kg as fed in the grower and finisher phases, respectively), which was either SDASOY, near-isogenic soya (CON) or fish oil (FISH). The LCn-3 PUFA content of the meat increased in the order CON, SDASOY and FISH. In breast meat with skin, the SDA concentration was 522, 13 and 37 (sem14·4) mg/100 g meat for SDASOY, CON and FISH, respectively. Equivalent values for C20 : 5n-3 (EPA) were 53, 13 and 140 (sem8·4); for C22 : 5n-3 (docosapentaenoic acid (DPA)) 65, 15 and 101 (sem3·5); for C22 : 6n-3 (DHA) 19, 9 and 181 (sem4·4). Leg meat (with skin) values for SDA were 861, 23 and 68 (sem30·1); for EPA 87, 9 and 258 (sem7·5); for DPA 95, 20 and 165 (sem5·0); for DHA 29, 10 and 278 (sem8·4). Aroma, taste and aftertaste of freshly cooked breast meat were not affected. Fishy aromas, tastes and aftertastes were associated with LCn-3 PUFA content of the meat, being most noticeable in the FISH leg meat (both freshly cooked and reheated) and in the reheated SDASOY leg meat.
UNDERSTANDING ETHNIC DIFFERENCES IN BEHAVIOUR RELATING TO SCHISTOSOMA MANSONI RE-INFECTION AFTER MASS TREATMENT
Authors: MOIRA ANGELA PINOT DE , KABATEREINE NARCIS B. , DUNNE DAVID W. , BOOTH MARK
Published: November 2010

It is now widely recognized that a decentralized approach to the control of parasitic infections in rural sub-Saharan populations allows for the design of more effective control programmes and encourages high compliance. Compliance is usually an indicator of treatment success, but cannot be used as a measure of long-term benefit since re-infection will be strongly influenced by a number of factors including the social ecology of a community. In this paper qualitative and quantitative methods are used to identify and understand the structural and behavioural constraints that may influence water contact behaviour and create inequalities with respect to Schistosoma re-infection following anti-helminth drug treatment. The research is set in a community where participant engagement has remained uniformly high throughout the course of a 10-year multidisciplinary study on treatment and re-infection, but where levels of re-infection have not been uniform and, because of variations in water contact behaviour, have varied by age, sex and ethnic background. Variations in the biomedical knowledge of schistosomiasis, socioeconomic constraints and ethnic differences in general attitudes towards life and health are identified that may account for some of these behavioural differences. The observations highlight the benefits of understanding the socio-ecology of control and research settings at several levels (both between and within ethnic groups); this will help to design more effective and universally beneficial interventions for control and help to interpret research findings.
INTELLIGENCE IN TAIWAN: PROGRESSIVE MATRICES MEANS AND SEX DIFFERENCES IN MEANS AND VARIANCES FOR 6- TO 17-YEAR-OLDS
Authors: LYNN RICHARD , CHEN HSIN-YI , CHEN YUNG-HUA
Published: November 2010

Data for Raven's Progressive Matrices are reported for a sample of 6290 6- to 17-year-olds in Taiwan. The Taiwanese obtained a mean IQ of 109.5, in relation to a British mean of 100. There was no difference in mean scores of boys and girls at age 7 years. At age 10 years girls obtained significantly higher scores than boys, and at ages 13 and 16 years boys obtained significantly higher scores than girls. There was no sex difference in variance at age 7 years. At ages 10, 13 and 16 years variance was significantly greater in boys.
Covered Farm Mortgage Bonds in the United States During the Late Nineteenth Century
Authors: Snowden Kenneth A.
Published: November 2010

Covered mortgage bonds have been used successfully in Europe for two centuries, but failed in the United States when introduced as farm mortgage debentures in the 1880s. Using firm-level data and a sample of loans made by one Kansas mortgage company, I find that debenture programs grew out of established loan brokerage operations and were used to fund mortgages that were difficult to broker because of size, term, or risk characteristics. Debentures broadened access to the interregional mortgage market and facilitated an expansion of western farm mortgage debt before the innovation failed in the mortgage crisis of the 1890s.

“[T]he availability of affordable mortgage financing is essential to turning the corner on the current housing crisis …. One option we have looked at extensively is covered bonds, which … have the potential to increase mortgage financing, improve underwriting standards, and strengthen U.S. financial institutions ….”

Secretary of Treasury Henry Paulson

July 28, 2008
The Sustainable Debts of Philip II: A Reconstruction of Castile's Fiscal Position, 1566–1596
Authors: Drelichman Mauricio , Voth Hans-Joachim
Published: November 2010

The defaults of Philip II have attained mythical status as the origin of sovereign debt crises. We reassess the fiscal position of Habsburg Castile, deriving comprehensive estimates of revenue, debt, and expenditure from new archival data. The king's debts were sustainable. Primary surpluses were large and rising. Debt-to-revenue ratios remained broadly unchanged during Philip's reign. Castilian finances in the sixteenth century compare favorably with those of other early modern fiscal states at the height of their imperial ambitions, including Britain. The defaults of Philip II therefore reflected short-term liquidity crises, and were not a sign of unsustainable debts.