bluuebunny/crossref_metadata_2025 huggingface dataset:
Die neuen Eisenbahn-Kundenrechte: Übersicht, erste Erfahrungen und Einordnungen
Authors: Hilpert-Janßen Thomas
Published: May 2024

Im vergangenen Jahr gab es bei den Kundenrechten im Eisenbahnverkehr einige Änderungen und Ankündigungen von weiteren Neuregelungen. So traten im Sommer 2023 nicht nur wesentliche Teile der Verordnung (EU) 2021/782 in Kraft, sondern es wurde auch das nationale Eisenbahnrecht novelliert. Mit den Änderungen im deutschen Recht wurden neben Anpassungen auf Grund des neuen EU-Rechts auch weitergehende Ansprüche für Kunden eingeführt, allerdings wurde auch von der in der Verordnung (EU) 2021/782 vorhandenen Option für Ausnahmen Gebrauch gemacht. Unter dem Datum des 29.11.2023 initiierte die EU-Kommission schließlich mehrere Verordnungsvorschläge und eine delegierte Verordnung, jeweils mit dem Schwerpunkt im multimodalen Bereich.
Superductile, Wavy Silica Nanostructures Inspired by Diatom Algae
Authors: Garcia Andre P. , Pugno Nicola , Buehler Markus J.
Published: March 2011

Biology implements intriguing structural design principles that allow for attractive mechanical properties—such as high strength, toughness, and extensibility despite being made of weak and brittle constituents, as observed in biomineralized structures. For example, diatom algae contain nanoporous hierarchical silicified shells, called frustules, which provide mechanical protection from predators and virus penetration. These frustules generally have a morphology resembling honeycombs within honeycombs, meshes, or wavy shapes, and are surprisingly tough when compared to bulk silica, which is one of the most brittle materials known. However, the reason for its extreme extensibility has not been explained from a molecular level upwards. By carrying out a series of molecular dynamics simulations with the first principles‐based reactive force field ReaxFF, the mechanical response of the structures is elucidated and correlated with underlying deformation mechanisms. Specifically, it is shown that for wavy silica, unfolding mechanisms are achieved for increasing amplitude and allow for greater ductility of up to 270% strain. This mechanism is reminiscent to the uncoiling of hidden length from proteins that allows for enhanced energy dissipation capacity and, as a result, toughness. We report the development of an analytical continuum model that captures the results from atomistic simulations and can be used in multiscale models to bridge to larger scales. Our results demonstrate that tuning the geometric parameters of amplitude and width in wavy silica nanostructures are beneficial in improving the mechanical properties, including enhanced deformability, effectively overcoming the intrinsic shortcomings of the base material that features extreme brittleness.
Gender differences in oral health in South Asia: Metadata imply multifactorial biological and cultural causes
Authors: Lukacs John R.
Published: March 2011

Objects:

This study was designed to examine the magnitude and etiology of gender differences in oral health. South Asia was selected for study because sex differences in caries rates exist in prehistory here, great cultural diversity provides context, and clinical reports document caries by gender.

Methods:

A literature survey yielded extensive data on caries rates in India, Nepal, Bangladesh, and Sri Lanka. The percentage of individuals with caries (prevalence) and the mean number of decayed, missing, and filled teeth (experience) comprise the data. Statistical tests for gender differences come from published sources or were independently computed.

Results:

Higher caries rates were found more often among females than males. The data show that: (a) in male children caries rates are greater than, or equal to, female rates, (b) the gender bias reverses (F > M caries rates) from adolescence through the reproductive years, (c) mature adults typically exhibit significant differences, with higher caries rates in females, (d) a male gender bias in adults is rare, and (e) though some studies find no significant gender difference in caries, a female bias dominates. Tooth loss is also greater in women than men and often results from caries (vs. periodontal disease).

Conclusions:

The gender gap in oral health exists in South Asia and results from genetic, hormonal, and cultural influences. Three cultural factors contribute to this gender gap South Asia: (a) the relative value of sons and daughters, (b) frequent fasting among Hindu women, and (c) the belief that dietary restrictions result in easier childbirth. Am. J. Hum. Biol., 2011. © 2011 Wiley‐Liss, Inc.
Fette und Öle als nachwachsende Rohstoffe in der Chemie
Authors: Biermann Ursula , Bornscheuer Uwe , Meier Michael A. R. , Metzger Jürgen O. , Schäfer Hans J.
Published: March 2011

Pflanzliche und tierische Öle und Fette waren und sind die wichtigsten nachwachsenden Rohstoffe der chemischen Industrie. In den vergangenen zehn Jahren hat eine beträchtliche Verlagerung der oleochemischen Produktion sowohl geographisch als auch hinsichtlich des Rohstoffs stattgefunden: von Nordamerika und Westeuropa nach Südostasien bzw. von Rindertalg zu Palmöl. Es wird in den kommenden Jahren von großer Bedeutung sein, neue Ölpflanzen mit gewünschten interessanten Eigenschaften für die chemische Nutzung einzuführen und anzubauen, was auch die agrokulturelle Biodiversität erhöhen könnte. Das Problem der industriellen Nutzung von Pflanzenölen, die vorzugsweise Nahrungsmittel sind, ist mit der Entwicklung der globalen Biodieselproduktion dringlicher geworden. Im Folgenden werden die bemerkenswerten Fortschritte diskutiert, die während des letzten Jahrzehnts mit Pflanzenölen und den daraus erhaltenen oleochemischen Basischemikalien in der organischen Synthese, der Katalyse und der Biotechnologie gemacht wurden. Diese in großem Maßstab als nachwachsende Kohlenstoffquelle zur Verfügung stehenden Rohstoffe können beispielsweise über eine ω‐Funktionalisierung von Fettsäuren mit inneren Doppelbindungen, die Anwendung der Olefinmetathese oder die De‐novo‐Synthese von Fettsäuren zu wichtigen Produkten der chemischen Industrie veredelt werden.
Release of fluorescent markers from phase‐separated gelatin‐maltodextrin hydrogels
Authors: Khan Rizwan S. , Nickerson Michael T. , Paulson Allan T. , Rousseau Dérick
Published: March 2011

Genipin‐crosslinked gelatin‐maltodextrin phase‐separated hydrogels consisting of gelatin‐continuous or bicontinuous microstructures were developed to regulate swelling and release behavior of four fluorescent markers of varying molecular weights [(fluorescein (332 Da) and FITC‐dextrans (FD) (4000–250,000 Da)]. Bicontinuous hydrogels showed significantly greater swelling than gelatin‐continuous hydrogels under all conditions (at pH 1.5 and 7.4 and three genipin/gelatin crosslinking ratios) (P < 0.05). With both microstructures, fluorescein showed the largest release rate and total release followed by FD 4000 Da, FD 40,000 Da, and FD 250,000 Da (P < 0.05). Marker molecular weight, pH, and crosslink ratio all affected the rate and amount of release. The mode of transport for the solvent and all markers was Fickian or slightly anomalous, with diffusional exponent (n) values ranging from 0.35 to 0.64. These results demonstrated that with the proper combination of crosslink density, solvent pH, and microstructure, hydrogels with a specified swelling behavior may be developed. This, coupled with a marker of appropriate size, can lead to controllable levels and rates of release. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Morphology, rheological, crystallization behavior, and mechanical properties of poly(L‐lactide)/ethylene‐co‐vinyl acetate blends with different VA contents
Authors: Li Yanli , Liu Li , Shi Yunyun , Xiang Fangming , Huang Ting , Wang Yong , Zhou Zuowan
Published: March 2011

Poly(L‐lactide)/ethylene‐co‐vinyl acetate (PLLA/EVA) blends with different contents of Vinyl Acetate (VA) in EVA phase were prepared through melt blending process. Although the composition of the blends was invariant (70/30), different phase morphologies were observed, namely, sea‐island morphologies for the blends with VA contents of 7.5, 18, and 28 wt %, whereas approximate co‐continuous morphology for the blend with VA content of 40 wt % was observed. The interfacial interaction between PLLA and EVA was visualized by Fourier transform infrared and rheological measurements. The nonisothermal and isothermal crystallization behaviors of the blends were investigated by wide angle X‐ray diffraction, Differential scanning calorimetry, and polarization optical microscope. Post‐thermal treatment was applied to improve the crystalline structure of PLLA. The results show that all the samples are mainly in amorphous state during the injection molding process. However, annealing promotes the second crystallization of PLLA matrix, leading to the improvement of the crystalline structure. Especially, the effect of annealing on crystalline structure of PLLA matrix is greatly dependent on the VA content of EVA. As expected, addition of EVA results in the improvement of the ductility and fracture toughness of the blends. The decreased tensile modulus and tensile strength can be enhanced through annealing process. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Investigating the accuracy of prediction pressure by laplace law in pressure‐garment applications
Authors: Aghajani Marzie , Jeddi Ali A. A. , Tehran M. Amani
Published: March 2011

To suitably treat and cure special skin damage, the exertion of pressure on the injured limb is advised by therapists. This type of therapy is called pressure therapy. Currently, pressure therapy is performed with pressure garments on the tissue. In all pressure‐garment applications, the amount of exerted pressure on the limb is very essential, and the success of treatment is extremely dependent on this pressure. Accordingly, the accurate prediction of exerted pressure is very important. Until now, in most related articles and researches, Laplace law has been used as the pressure predictor equation. In this study, the accuracy of Laplace law for two types of structures, elastic fabric and rubber, were investigated. The obtained results indicate that the measured pressure in all specimens was considerably more than that predicted by Laplace law. Therefore, the accuracy of Laplace law was proven to be inefficient for the prediction of pressure, and as such, more investigation is recommended. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Pervaporation separation of IPA‐water mixtures through 4A zeolite‐filled sodium alginate membranes
Authors: Sudhakar H. , Venkata Prasad C. , Sunitha K. , Chowdoji Rao K. , Subha M. C. S. , Sridhar S.
Published: March 2011

Incorporation of zeolites into natural polymers has been shown experimentally to enhance both the flux and selectivity in pervaporative dehydration separation of organic compounds. Pervaporation is a promising membrane technique for separation of volatile organic compounds (VOCs)/water mixtures. In this study, hydrophilic sodium alginate (SA) mixed membranes were prepared using solution casting technique by incorporating zeolites into the polymer matrix. The prepared membranes were characterized by ATR‐Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), scanning electron microscopy (SEM), Thermal Gravimetric Analysis (TGA), and differential scanning calorimetry (DSC) were tested in a laboratory scale pervaporation experimental set‐up. The effect of experimental parameters such as the type and composition of zeolites on permeation flux and selectivity was investigated. When tested on IPA‐water mixtures, the zeolite‐filled membrane was found to give much higher selectivity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Copolymer hydrogel microspheres consisting of modified sulfate chondroitin‐co‐poly(N‐isopropylacrylamide)
Authors: Reis Adriano V. , Guilherme Marcos R. , S de Almeida Elizângela A. M. , Kunita Marcos H. , Muniz Edvani C. , Rubira Adley F. , Tambourgi Elias B.
Published: March 2011

Modified chondroitin sulfate (π‐CdS) microspheres were synthesized by way of crosslinking‐copolymerization reaction with N‐isopropylacrylamide (NIPAAm), yielding CdS‐co‐PNIPAAm copolymer network. The incorporation of vinyl groups onto the CdS was processed with the use of glycidyl methacrylate (GMA) in an aqueous solution of pH 3.5 under stirring speed of 800 rpm at 50°C. 13C NMR and 1H NMR spectra of CdS treated with the GMA indicated the formation of 3‐methacryloyl‐1‐glyceryl ester of π‐CdS and 3‐methacryloyl‐2‐glyceryl ester of π‐CdS that are the reaction products resultant of an epoxide ring‐opening mechanism via. The synthesis of microspheres was performed via radical reaction of the vinyl groups at the π‐CdS with vinyl groups at the NIPAAm in a water−benzyl alcohol microemulsion. The formation of spherical structures is the result of the polymerization‐crosslinking reaction of the π‐CdS with the NIPAAm monomers at the droplets of water, in view that both reactants have hydrophilic characteristics at the temperature at which the reaction was processed. The pure CdS hydrogel microspheres showed a slightly cracked structure with a lower diameter range while the CdS‐co‐PNIPAAm hydrogel microspheres showed a flat and tight structure with a more regular mass distribution. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Use of biocrude derived from woody biomass to substitute phenol at a high‐substitution level for the production of biobased phenolic resol resins
Authors: Cheng Shuna , D'Cruz Ian , Yuan Zhongshun , Wang Mingcun , Anderson Mark , Leitch Mathew , Xu Chunbao (Charles)
Published: March 2011

Phenolic bio‐oil produced by the direct liquefaction of Eastern white pine (Pinus Strobus L.) sawdust in a hot‐compressed ethanol‐water (1:1 w/w) medium at 300 °C was used to partially substitute for phenol in the synthesis of bio‐oil‐phenol‐formaldehyde (BPF) resol resins. Bio‐based resol resins with high levels of phenol substitution (up to 75 wt%) could be used as plywood adhesives because of the low molecular weights found for the phenolic bio‐oil (weight‐average molecular weight = 1072 g/mol, number‐average molecular weight = 342 g/mol). The properties of the BPF resol resins were analyzed by differential scanning calorimetry, Fourier transform infrared spectroscopy, gel permeation chromatography, and thermogravimetric analysis. All of the experimental BPF resins possessed broad molecular weight distributions but had similar chemical/thermal properties compared to a conventional phenol–formaldehyde (PF) resol resin reference (or 0 wt % BPF resin). The BPFs exhibited the typical properties of a thermosetting PF resin, for example, an exothermic curing temperature of 140–150°C and an acceptable residual carbon yield of 48–72 wt % nonvolatile content at 700°C. The experimental BPFs were applied as adhesives in the assembly of plywood, and then, the dry/wet tensile strengths were evaluated. The tensile strengths of the dry plywood samples bonded with the BPF resins up to a high ratio value of 75 wt % bio‐oil exceeded or were comparable to that of the conventional pure PF resin adhesive. All of the BPF‐resin‐bonded plywood samples gave wet tensile strengths comparable to those of the conventional PF adhesive. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Flame‐retardant synergism of sepiolite and magnesium hydroxide in a linear low‐density polyethylene composite
Authors: Gul Rahmat , Islam Atif , Yasin Tariq , Mir Sadullah
Published: March 2011

A synergistic effect on flame retardancy, thermal stability, and mechanical properties was found when sepiolite was incorporated into a linear low‐density polyethylene (LLDPE)/magnesium hydroxide (MH) composite. Different amounts of sepiolite (up to a maximum concentration of 15 phr) were added to a standard LLDPE/MH formulation, and vinyltriethoxysilane was used as a compatibilizer as well as a crosslinking agent. The thermal stability and the oxidation induction time increased with increasing sepiolite content in the LLDPE composites. Limiting oxygen index (LOI) results indicated an increase in LOI with the addition of sepiolite, and an LOI value of 36.5% was observed with 15 phr sepiolite in the LLDPE/MH formulation. The addition of sepiolite increased the gel content and tensile strength of all samples and lowered the elongation at break. The heat deflection, Vicat softening temperature, and hardness were also improved by the incorporation of sepiolite. This synergistic behavior of sepiolite with MH could be used in halogen‐free, flame‐retardant LLDPE formulations. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Novel physical hydrogels composed of opened‐ring poly(vinyl pyrrolidone) and chitosan derivatives: Preparation and characterization
Authors: Abashzadeh S. , Hajimiri M. H. , Atyabi F. , Amini M. , Dinarvand R.
Published: March 2011

A novel, physically stabilized hydrogel system composed of chitosan (Chi) or its derivatives [e.g., carboxymethyl chitosan (CMC), sodium carboxymethyl chitosan, or trimethyl carboxymethyl chitosan (TMCMC)] with poly(vinyl pyrrolidone) (PVP) or opened‐ring poly(vinyl pyrrolidone) (OR–PVP) were prepared and characterized. TMCMC was synthesized by a novel method with dimethylsulfate as the methylation agent. The synthesized materials were characterized by Fourier transform infrared spectroscopy, 1H‐NMR, 13C‐NMR, and size exclusion chromatography. The mechanical properties, gel fraction, swelling behavior, and water state of the prepared hydrogels were investigated. Gelation occurred when the OR–PVP and Chi solutions were blended within a few seconds. However, the gelation of the OR–PVP and CMC solutions needed pH adjustment. No gelation occurred when the solutions of TMCMC and PVP or OR–PVP were blended. The quaternization or protonization of NH2 groups may have prevented the gelation of the solutions. The amino groups of Chi derivatives should have been free to take part in hydrophilic bonds between the two polymers. The physical entanglement of polymeric chains and strong hydrogen bonds between the polymers were considered as mechanisms for the formation of the physical hydrogels. The physical hydrogels showed ionic and pH‐sensitive swelling properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis, characterization, and soil biodegradation study of polyamides derived from the novel bioactive diacid monomer 5‐(2‐phthalimidoethanesulfonamido) isophthalic acid
Authors: Karimi Zarchi Mohammad Ali , Tayefi Mohammad , Tirgir Farhang , Sabzalian Mohammad R.
Published: March 2011

A new bioactive diacid monomer, 5‐(2‐phthalimidoethanesulfonamido) isophthalic acid (6), was synthesized in three steps. This monomer can be regarded as biologically active aromatic diacid and may be used in the design of biodegradable and biological materials. This monomer was polymerized with several aromatic diamines by step‐growth polymerization to give a series of biodegradable and highly thermally stable polyamides (PAs) with good yield (70–82%) and moderate inherent viscosity between 0.38–0.68 dL/g in a system of triphenylphosphite/pyridine/N‐methyl‐2‐pyrolidone/CaCl2. The new aromatic diacid 6 and all of the PAs derived from this diacid and aromatic diamines were characterized by Fourier transform infrared, 1H‐NMR, 13C‐NMR, and elemental analysis techniques. The thermal stability of the PAs was determined by thermogravimetric analysis and differential scanning calorimetry techniques under a nitrogen atmosphere, and we found that they were moderately stable. The soil biodegradability behavior of 6 and all of the PAs derived from this diacid and aromatic diamines were investigated in culture media, and we found that the synthesized diacid 6 and all of the PAs were biodegradable under a natural environmental. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Synthesis and degradation of sorbitol‐based polymers
Authors: Pasupuleti Sasikiran , Madras Giridhar
Published: March 2011

A new class of biodegradable copolyesters was synthesized by the catalyst‐free melt condensation of sorbitol with citric acid, tartaric acid, and sebacic acid. The resulting polymers were designated as poly(sorbitol citric sebacate) [p(SCS)] and poly(sorbitol tartaric sebacate) [p(STS)]. The synthesized polymers were characterized by Fourier transform infrared spectroscopy, 1H‐NMR spectroscopy, and differential scanning calorimetry analysis. Porous spongelike scaffolds were prepared with a salt‐leaching technique and characterized with scanning electron microscopy. Tensile testing of the p(SCS) and p(STS) polymers showed that they exhibited a wide range of mechanical properties. The Young's modulus and tensile strengths of the polymers ranged from 1.06 ± 0.12 to 462.65 ± 34.21 MPa and from 0.45 ± 0.04 to 20.32 ± 2.54 MPa, respectively. In vitro degradation studies were performed on disc‐shaped polymer samples. The half‐life of the polymers ranged from 0.54 to 38.52 days. The percentage hydration of the polymers was in the range 9.36 ± 1.26 to 78.25 ± 1.91, with sol contents of 2–14%. At any given polymer composition, the Young's modulus and tensile strength of p(SCS) was higher than that of p(STS), whereas the degradation rates of p(SCS) was lower than that of p(STS). This was attributed to the structural difference between the citric and tartaric monomers and to the degree of crosslinking. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effect of vanadium pentoxide on the mechanical, thermal, and electrical properties of poly(vinyl alcohol)/vanadium pentoxide nanocomposites
Authors: Wacharawichanant Sirirat , Wutanasiri Nareerut , Srifong Paveena , Meesangpan Usarat , Thongyai Supakanok
Published: March 2011

In this study, we examined the effect of vanadium pentoxide (V2O5) on the mechanical, thermal, and morphological properties of poly(vinyl alcohol) (PVA)/V2O5 nanocomposites. The PVA/V2O5 nanocomposites were prepared by solution mixing, followed by film casting. The results show that the Young's moduli of the resulting nanocomposites films were higher than the pure PVA modulus with increasing V2O5 content, and it reached a maximum point at about 0.4 wt % V2O5 content at 8.55 GPa. The tensile strength and stress at break increased with increasing V2O5 content. The addition of V2O5 did not affect the melting temperature. The crystallization temperatures of PVA were significantly changed with increasing V2O5 content. The 5% weight loss degradation temperature of the nanocomposites was measured by thermogravimetric analysis. The degradation temperatures of the V2O5 nanocomposites increased with increasing filler content and were higher than the degradation temperature of pure PVA; this showed a lower thermal stability compared to those of the nanocomposites. The results show that the thermal stability increased with the incorporation of V2O5 nanoparticles. The dielectric constant of PVA had a tendency to improve when the dispersion of particles was effective. The morphology of the surfaces the nanocomposites was examined by scanning electron microscopy. We observed that the dispersion of the V2O5 nanoparticles was relatively good; only few aggregations existed after the addition of the V2O5 nanoparticles at greater than 0.4 wt %. In perspective, the addition of 0.4 wt % V2O5 nanoparticles into PVA maximized the mechanical, thermal, and electrical properties. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Studies on the Amidoximation of Polyacrylonitrile Films: Influence of Synthesis Conditions
Authors: Mishra Abhishek , Sharma Shiromani , Gupta Bhuvanesh
Published: March 2011

Chemical transformation of acrylic membranes with hydroxylamine hydrochloride (HA) was carried out to introduce amidoxime groups. It was found that the reaction conditions, such as reaction time, HA concentration and temperature influence the amidoxime content, significantly. A sharp enhancement in the amidoximation at 80°C was observed. The FTIR studies showed a significant loss of nitrile groups during amidoximation process. Optimum conditions for the amidoximation process were investigated. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Investigation in thermal endurance of polyesterimide used in electrical machines
Authors: Nedjar M.
Published: March 2011

The purpose of this investigation is to evaluate thermal lifetime of polyesterimide using Weibull statistics. Thermal aging was performed on twisted pair specimens of copper wire insulated by a polyesterimide layer. The study shows that breakdown voltage varies versus aging time. Its increase is allotted to a crosslinking inducing a diminution of mean‐free path of charge carriers leading thereby to a mobility decrease, whereas its decrease is attributed to the viscosity diminution expressing a weakening of molecular bonds and a mobility increase of charge carriers. Shape parameter changes in function of aging time. Its increase is ascribed to an arrangement of the molecular structure, whereas its decrease is due to an augmentation in the size of defects. The thermal endurance graph is a straight line indicating that the degradation is governed by a first‐order chemical reaction. Activation energy and temperature index were determined. The degradation is governed by the dissolution of copper into the polymer and accelerates its degradation occurring at the polyesterimide–copper interface. Oxygen can diffuse into the insulation and attack copper resulting in the formation of copper oxide. The degradation is caused by the scission of imide and ester bonds. The process is followed by a change in color and a presence of cracks. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Effects of rice straw fiber morphology and content on the mechanical and thermal properties of rice straw fiber‐high density polyethylene composites
Authors: Ming‐Zhu Pan , Chang‐Tong Mei , Xu‐Bing Zhou , Yun‐Lei Pu
Published: March 2011

Rice straw fiber‐high density polyethylene (HDPE) composites were prepared to investigate the effects of rice straw fiber morphology (rice straw refined fiber, rice straw pellet, rice straw strand), fiber content (20 and 40 wt %), and maleic anhydride polyethylene (MAPE) concentration (5 wt %) on the mechanical and thermal properties of the rice straw fiber‐HDPE composites in this study. Rice straw refined fiber exhibited more variability in length and width, and have a higher aspect ratio of 16.3. Compared to the composites filled of rice straw pellet, the composites made of the refined fiber and strand had a slightly higher tensile strength and lower tensile elongation at break. The tensile and flexural strength of the composites increased slightly with increasing rice straw fiber content up to 40 wt %, while the tensile elongation at break decreased. With addition MAPE, the composites filled with 20 wt % rice straw fiber showed an increase in tensile, flexural and impact strength and a decrease in tensile elongation at break. Differential scanning calorimetry showed that the fiber addition and morphology had no appreciable effect on the crystallization temperature of the composites but decreased the crystallinity. The scanning electron microscopy observation on the fracture surface of the composites indicated that introduction of MAPE to the system resulted in promotion in fiber dispersion, and an increase in interfacial bonding strength. Fiber breakage occurred significantly in the composites filled with refined fiber and strand after extruding and injection processing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Herbal drug incorporated antibacterial nanofibrous mat fabricated by electrospinning: An excellent matrix for wound dressings
Authors: Suganya S. , Senthil Ram T. , Lakshmi B. S. , Giridev V. R.
Published: March 2011

Nano‐components and nano‐systems for health care and medical applications are the focus of many research projects worldwide. Nanofibrous membranes are highly soft materials with high surface‐to‐volume ratios, and therefore can serve as excellent carriers for therapeutic agents that are antibacterial or accelerate wound healing. PCL/PVP Nanofiber mat containing chloroform: methanol (4:1) crude bark extract of Tecomella undulata, a medicinal plant widely known for its traditional medical applications including its wound healing ability, were prepared and evaluated for their antibacterial properties. With good drug stability and high drug‐loading efficacy, the incorporation of herbal extract in the polymer media did not appear to influence the morphology of the resulting fibers, as both the drug‐free and the drug‐loaded nanofibers remained unaltered, microscopically. Activity was tested against standard strains of Pseudomonas aeruginosa MTCC 2297, Staphylococcus aureus ATCC 933, Escherichia coli (IP‐406006). Extract loaded PCL/PVP nanofiber mat were able to inhibit the growth of the bacterial strains which indicate that it could act not only as a drug delivery system but also in the treatment of wound healing or dermal bacterial infections thereby proving a potential application for use as a wound dressing. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011
Polyaniline‐Intercalated Molybdenum Oxide Nanocomposites: Simultaneous Synthesis and their Enhanced Application for Supercapacitor
Authors: Zheng Lei , Xu Yang , Jin Dong , Xie Yi
Published: March 2011

A new and universal synthetic strategy to hybridize metal oxides and conduct polymer nanocomposites has been proposed in this work. The simultaneous reaction process, which includes the generation of metal oxide layers, the oxidation polymerization of monomers, and the in situ formation of polymer–metal oxides sandwich structure is successfully realized and results in the unique hybrid polyaniline (PANI)‐intercalated molybdenum oxide nanocomposites. The peroxomolybdate proved to play a dual role as the precursor of the inorganic hosts and the oxidizing agent for polymerization. The as‐obtained hybrid nanocomposites present a flexible lamellar structure by oriented assembly of conductive PANI chains in the MoO3 interlayer, and thus inherit excellent electrical performance and possess the potential of active electrode materials for electrochemical energy storage. Such uniform lamellar structure together with the anticipated high conductivity of the hybrid PANI/MoO3 nanocomposites afford high specific capacitance and good stability during the charge–discharge cycling for supercapacitor application.
Diode‐Like I–V Characteristics of a Nonplanar Polyaromatic Compound: a Spectroscopic Study of Isolated and Stacked Dibenzo[g,p]chrysene
Authors: Lee Shern‐Long , Huang Min‐Jie , Chen Chun‐hsien , Wang Cheng‐I , Liu Rai‐Shung
Published: March 2011

In this scanning‐tunneling‐microscopy/spectroscopy study (STM/STS), samples of isolated and close‐packed dibenzo[g,p]chrysene (DBC), a nonplanar polyaromatic compound, are used as model systems to demonstrate the effect of intermolecular interactions on the electronic structures. For dropcast films, DBC molecules adopt an edge‐on orientation in a close‐packed structure on graphite. Isolated DBC molecules are prepared on graphite from a DBC‐coated STM tip by a ca. 7 V/10 μs pulse. STS spectra for both isolated‐ and close‐packed DBC molecules exhibit diode‐like I–V curves in which the latter shows a turn‐on voltage (0.47 V) smaller than that of the former (0.91 V). The diode‐like behaviors are attributed to the more‐facile tunneling of electrons through the HOMO of DBC than through the LUMO. The reduced turn‐on voltage for the films is ascribed to the diminished HOMO–LUMO gap based on the results of DFT (density functional theory) simulations for the energy‐level couplings of π‐stacked DBC molecules.
The Effect of the Buffering Capacity of the Supporting Electrolyte on the Electrochemical Oxidation of Dopamine and 4‐Methylcatechol in Aqueous and Nonaqueous Solvents
Authors: Chen Shanshan , Tai Kah Yieng , Webster Richard D.
Published: March 2011

Dopamine was electrochemically oxidized in aqueous solutions and in the organic solvents N,N‐dimethyl‐formamide and dimethylsulfoxide containing varying amounts of supporting electrolyte and water, to form dopamine ortho‐quinone. It was found that the electrochemical oxidation mechanism in water and in organic solvents was strongly influenced by the buffering properties of the supporting electrolyte. In aqueous solutions close to pH 7, where buffers were not used, the protons released during the oxidation process were able to sufficiently change the localized pH at the electrode surface to reduce the deprotonation rate of dopamine ortho‐quinone, thereby slowing the conversion into leucoaminochrome. In N,N‐dimethylformamide and dimethylsulfoxide solutions, in the absence of buffers, dopamine was oxidized to dopamine ortho‐quinone that survived without further reaction for several minutes at 25 °C. The voltammetric data obtained in the organic solvents were made more complicated by the presence of HCl in commercial sources of dopamine, which also underwent an oxidation process.
Effect of injury on S1 dorsal root ganglia in an experimental model of neuropathic faecal incontinence
Authors: Peirce C , O'Herlihy C , O'Connell P R , Jones J F X
Published: March 2011

Background

An experimental model of neuropathic faecal incontinence has recently been established. This study aimed to quantify and compare the effect of crush and compression injury on first-order sensory neurones of the inferior rectal nerve (IRN) using a nuclear marker of axonal injury, activating transcription factor (ATF) 3.

Methods

Eighteen Wistar rats were allocated to three groups: an unoperated control group, an IRN crush group (positive control) and a retrouterine balloon compression group. Five days after surgery, all animals were anaesthetized and perfused with fixative, and S1 dorsal root ganglia (DRG) were harvested. The tissue was sampled and neuronal nuclear ATF-3 expression calculated.

Results

Estimated total S1 DRG ATF-3 nuclear labelling was higher in the nerve crush (median (interquartile range) 171 (60–824) cells) and balloon compression (59 (20–274) cells) groups, compared with that in the unoperated control group (9 (3–24) cells) (P = 0·001 and P = 0·008 respectively). In all groups, most neurones displaying the marker of injury were of the C-fibre class.

Conclusion

This study confirmed the presence of axonal injury in a pelvic compression model of obstetric injury. C-fibre afferent pathways appeared to be most vulnerable. Neuromodulation may function through augmentation of residual C-fibre pathways.
Impact of endoscopic assessment and treatment on operative and non-operative management of acute oesophageal perforation
Authors: Kuppusamy M K , Felisky C , Kozarek R A , Schembre D , Ross A , Gan I , Irani S , Low D E
Published: March 2011

Background

Surgeons have not typically utilized an endoscopic approach for diagnosis and management of acute oesophageal perforation, mainly due to fears of increased mediastinal contamination. This study assessed the evolution of endoscopic approaches and their effect on outcomes over time in acute oesophageal perforation.

Methods

All patients with documented acute oesophageal perforation between 1990 and 2009 were enrolled prospectively in an Institutional Review Board-approved database.

Results

Of 81 patients who presented during the study period, 52 had upper gastrointestinal endoscopy for diagnosis alone (12 patients; 23 per cent) or as a component of acute management (40 patients; 77 per cent). Use of endoscopy increased from four of 13 patients in the first 5 years of the study to 20 of 24 patients in the final 5 years. Endoscopy was used in conjunction with surgery in 28 patients, of whom 21 underwent primary repair, three had resection, and one a diversion; 12 patients in this group had hybrid operations (combination of surgical and endoscopic management). Primary endoscopic treatment was used in 15 patients (29 per cent), most commonly involving stent placement (7). Of those having endoscopy, complication rates improved (from 3 of 4 to 8 of 20 patients), as did mean length of stay (from 21·8 to 13·4 days) between the initial and final 5 years of the study. There were two deaths (4 per cent). Of 21 patients who had both endoscopic assessment and management in the operating room, endoscopy identified additional pathology in ten, leading to a change in management plan in five patients.

Conclusion

Endoscopy is a safe and important component of the management of acute oesophageal perforation. It provides additional information that modifies treatment, and its wider use should result in improved outcomes.
Doing Research with Imprisoned Adult Male Child Sexual Abusers: Reflecting on the Challenges
Authors: Roberts Susan
Published: March 2011

Much research has been undertaken within the prison environment, particularly in relation to sexual offenders. Yet, little attention has been paid to the task of doing research with imprisoned adult male child sexual abusers. This is a personal account of the experiences of a female researcher and the issues which emerged as part of the process of undertaking a qualitative, descriptive research study with 101 imprisoned adult males convicted of sexual offences against children. Consideration is given to the challenges which presented prior to and during the fieldwork phase; the means by which these were dealt with; the impact of the data collection process on the researcher; and the part played by gender in that. Copyright © 2011 John Wiley & Sons, Ltd.

‘This is a personal account of the experiences of a female researcher’
Good Practice in Social Care for Refugee and Asylum‐seeking Children
Authors: Newbigging Karen , Thomas Nigel
Published: March 2011

This article seeks to identify key components of good practice in social care services for safeguarding refugee and asylum‐seeking children. It is based on a wider research study, conducted in England, Wales and Northern Ireland, which aimed to identify indicators and examples of good practice in social care for asylum seekers and refugees (both adults and children). Methods included a systematic literature review, focus groups with asylum seekers and refugees, and a survey of voluntary and statutory agencies. This paper reflects on the findings as they relate to children, including both unaccompanied children and those in families, with particular attention to safeguarding issues, and identifies key components of good practice from a synthesis of the findings. The primary component identified is a clear commitment to seeing the wellbeing of children and young people as the primary focus of practice, rather than the demands of immigration policy. Others include provision of safe and appropriate accommodation, support for engagement in appropriate education and leisure pursuits, attention to emotional well‐being, good support and information for families, and inclusion of families and communities in the safeguarding agenda. The research showed that the needs of unaccompanied asylum‐seeking children and young people tend to be more visible than those living with their families, and that more research is needed, particularly in relation to the latter group. Copyright © 2011 John Wiley & Sons, Ltd.

‘The wellbeing of children and young people as the primary focus of practice, rather than the demands of immigration policy’
Protein kinase B/Akt may regulate G2/M transition in the fertilized mouse egg by changing the localization of p21Cip1/WAF1
Authors: Wu Di‐Di , Feng Chen , Xu Xiao‐Yan , Xiao Jian‐Ying , Liu Chao , Meng Jun , Wang En‐Hua , Yu Bing‐Zhi
Published: March 2011

Protein kinase B (PKB, also called Akt) is known as a serine/threonine protein kinase. Some studies indicate that the Akt signalling pathway strongly promotes G2/M transition in mammalian cell cycle progression, but the mechanism remains to be clarified, especially in the fertilized mouse egg. Here, we report that the expression of Akt at both the protein and mRNA level was highest in G2 phase, accompanied by a peak of Akt activity. In addition, the subcellular localization of p21Cip1/WAF1 has been proposed to be critical in the cell cycle. Hence, we detected the expression and localization of p21Cip1/WAF1 after injecting fertilized mouse eggs with Akt mRNA. In one‐cell stage fertilized embryos microinjected with mRNA coding for a constitutively active myristoylated Akt (myr‐Akt), p21Cip1/WAF1 was retained in the cytoplasm. Microinjection of mRNA of kinase‐deficient Akt(Akt‐KD) resulted in nuclear localization of p21Cip1/WAF1. Meanwhile, microinjection of different types of Akt mRNA affected the phosphorylation status of p21Cip1/WAF1. However, there was no obvious difference in the protein expression of p21Cip1/WAF1. Therefore, Akt controls the cell cycle by changing the subcellular localization of p21Cip1/WAF1, most likely by affecting the phosphorylation status of p21Cip1/WAF1. Copyright © 2011 John Wiley & Sons, Ltd.
Comparing EndoPAT and BIOPAC measurement of vascular responses to mental stress
Authors: Martin Elizabeth A. , Nelson Rebecca E. , Felmlee‐Devine M. Donna , Brown Troy E. , Lerman Amir
Published: March 2011

There are currently no comparison measurements of stress‐induced changes in vascular function during acute mental stress tests to measurements made by BIOPAC MP150 systems technology, a standard polygraph device used to detect deception during polygraph examinations in military or law enforcement applications. Vascular responses to reactive hyperaemia and acute mental stress in 25 healthy subjects were measured by both peripheral arterial tonometry (EndoPAT) and a blood pressure cuff attached to a pressure transducer (BIOPAC) and compared. Reactive hyperaemia was performed at baseline and following three acute mental stress tests. There was no difference in vascular reactivity at baseline and following acute mental stress, as measured by EndoPAT or BIOPAC systems (p > 0·05). Mental stress ratios measured by EndoPAT were significantly different than those measured by BIOPAC (p < 0·01). These data suggest that EndoPAT measurements of vascular responses to acute mental stress may be more specific and sensitive than measurements using the BIOPAC system. Copyright © 2011 John Wiley & Sons, Ltd.
Adenylate‐Forming Enzymes of Rubradirin Biosynthesis: RubC1 Is a Bifunctional Enzyme with Aminocoumarin Acyl Ligase and Tyrosine‐Activating Domains
Authors: Boll Björn , Hennig Susanne , Xie Chunsong , Kyong Sohng Jae , Heide Lutz
Published: March 2011

The biosynthesis of aminocoumarin antibiotics requires two acyladenylate‐forming enzymes: one for the activation of L‐tyrosine as a precursor of the aminocoumarin moiety and another for the linkage of an acyl moiety to the aminocoumarin moiety. Unexpectedly, the biosynthetic gene cluster of the aminocoumarin antibiotic rubradirin was found to contain three genes for putative acyladenylate‐forming enzymes of aminocoumarin biosynthesis and conjugation. We expressed, purified, and investigated these three proteins. Orf4 (55 kDa) was shown to be an active aminocoumarin acyl ligase. RubF6 (56 kDa) was inactive, but could be converted into an active enzyme by site‐directed mutagenesis. RubC1 (138 kDa) was shown to be a unique bifunctional enzyme, comprising an aminocoumarin acyl ligase, and tyrosine‐adenylation and peptidyl‐carrier domains. This natural hybrid enzyme is unique among known proteins. A hypothesis is proposed as to how such an enzyme could offer a particularly effective machinery for aminocoumarin antibiotic biosynthesis.
Unsteady Mixing Characteristics in a Vessel with Forward‐Reverse Rotating Impeller
Authors: Woziwodzki S.
Published: March 2011

Usually, mixing is carried out in a vessel with four baffles and a single impeller. In some applications, however, the use of a baffled vessel is not recommended. One of the stirring methods used instead is unsteady agitation with forward‐reverse rotating impellers. The aim of this work was to characterize the agitation characteristics in a baffled and an unbaffled vessel with a turbine impeller. Mixing time and mixing power were evaluated in relation to the presence of baffles and the frequency of forward‐reverse rotation. It was found that the frequency of oscillation does not affect either the mixing time and mixing power values or the drag and added mass coefficients. Power requirements and mixing time were higher compared to the steady mixing conditions in a baffled vessel. The results showed that it is not recommended to use baffles because they have no influence on unsteady mixing.
Synthesis, Structure, and Biological Activity of des‐Side Chain Analogues of 1α,25‐Dihydroxyvitamin D3 with Substituents at C18
Authors: Verlinden Lieve , Verstuyf Annemieke , Eelen Guy , Bouillon Roger , Ordóñez‐Morán Paloma , Larriba María Jesús , Muñoz Alberto , Rochel Natacha , Sato Yoshiteru , Moras Dino , Maestro Miguel , Seoane Samuel , Dominguez Fernando , Eduardo‐Canosa Silvina , Nicoletti Daniel , Moman Edelmiro , Mouriño Antonio
Published: March 2011

An improved synthetic route to 1α,25‐dihydroxyvitamin D3 des‐side chain analogues 2 a and 2 b with substituents at C18 is reported, along with their biological activity. These analogues display significant antiproliferative effects toward MCF‐7 breast cancer cells and prodifferentiation activity toward SW480‐ADH colon cancer cells; they are also characterized by a greatly decreased calcemic profile. The crystal structure of the human vitamin D receptor (hVDR) complexed to one of these analogues, 20(17→18)‐abeo‐1α,25‐dihydroxy‐22‐homo‐21‐norvitamin D3 (2 a) reveals that the side chain introduced at position C18 adopts the same orientation in the ligand binding pocket as the side chain of 1α,25‐dihydroxyvitamin D3.
The prediction of amino proton chemical shifts using optimally selected wave function
Authors: Shaghaghi Hoora , Iravani Maryam , Tafazzoli Mohsen
Published: March 2011

Gas phase amino proton chemical shifts in the 54 of amines have been predicted using Gauge‐independent atomic orbital (GIAO) method and optimally selected wave function. The effects of electron correlation, triple‐ξ valance shell, diffuse function, and polarization function on calculated amino proton chemical shifts have been investigated using factorial design as a multivariate technique. Different optimized wave functions for different groups of amines were recommended. A wave function as the best level of the theory is proposed for homologue amines covered. In this context, B3LYP/6‐311+G and HF/6‐311+G wave functions have been recommended as the best and the most efficient level of theory for calculating amino proton chemical shifts of alkylamines and arylamines respectively. © 2011 Wiley Periodicals, Inc. Concepts Magn Reson Part A 38A: 25–32, 2011.
NMR signal detection using inductive coupling: Applications to rotating microcoils
Authors: Jacquinot Jacques‐François , Sakellariou Dimitris
Published: March 2011

Sensitivity in solid‐state nuclear magnetic resonance can be improved by the use of rotating microcoils (1). The connection to the rest of the electronics is performed through resonant inductive coupling. This mode of detection of nuclear induction has major advantages as it provides a wireless way to obtain extremely high radio‐frequency amplitudes per unit current under sample rotation and thus improved sensitivity for size‐limited samples. We review the circuit electronics and discuss experimental optimization of the probe and coil parameters. We also present alternative geometries for coupling between rotating coils and we explicitly calculate the signal enhancement. Two practical cases are presented, namely a standard magic angle sample spinning probe and a double sample rotation probe. We conclude with a theoretical discussion about the limits of detection attainable with coil miniaturization. © 2011 Wiley Periodicals, Inc. Concepts Magn Reson Part A 38A: 33–51, 2011.