bluuebunny/crossref_metadata_2025 huggingface dataset:
Response of mice connective tissue to intracanal dressings containing chlorhexidine
Authors: Pereira Maristela Soares Swerts , Faria Gisele , Bezerra Da Silva Léa Assed , Tanomaru‐Filho Mário , Kuga Milton Carlos , Rossi Marcos A.
Published: August 2012

Substances containing chlorhexidine (CHX) have been studied as intracanal medicaments. The aim of the present study was to characterize the response of mouse subcutaneous connective tissue to CHX‐containing medications by conventional optical microscopy. The tissue response was evaluated by implanting polyethylene tubes containing one of the substances evaluated: Calen paste + 0.5% CHX, Calen + 2% CHX, 2% CHX gel, and Calen paste (control). After experimental periods of 7, 21, and 63 days, the implants (n = 10) were removed along with the subcutaneous connective tissue. Tissue samples were subjected to histological processing, and sections were stained with hematoxylin and eosin. Qualitative and quantitative analyses of the number of inflammatory cells, blood vessels, and vascularized areas were performed. Results were analyzed by ANOVA and Tukey tests with the significance level set at 5%. We concluded that Calen + 0.5% CHX led to reparative tissue response in contrast with Calen + 2% CHX and 2% CHX gel, which induced persistent inflammatory response, pointing to the aggressive nature of this mixture. When Calen + 2% CHX and 2% CHX gel were compared, the latter induced more intense inflammatory response. Microsc. Res. Tech., 2012. © 2012 Wiley Periodicals, Inc.
A multipartite Ramsey number for odd cycles
Authors: Benevides Fabrıcio Siqueira
Published: August 2012

In this article we study multipartite Ramsey numbers for odd cycles. Our main result is the proof that a conjecture of Gyárfás et al. (J Graph Theory 61 (2009), 12–21), holds for graphs with a large enough number of vertices. Precisely, there exists n0 such that if n⩾n0 is a positive odd integer then any two‐coloring of the edges of the complete five‐partite graph K(n − 1)/2, (n − 1)/2, (n − 1)/2, (n − 1)/2, 1 contains a monochromatic cycle of length n. © 2011 Wiley Periodicals, Inc. J Graph Theory
On r‐Connected Graphs with No Semi‐topological r‐Wheel
Authors: Horev Elad , Lomonosov Michael
Published: August 2012

A semi‐topological r‐wheel, denoted by , is a subdivision of the r‐wheel preserving the spokes. This paper describes the r‐connected graphs having no ‐subgraphs. For , these are shown to be only , while the class of 3‐connected ‐free graphs is unexpectedly rich. First, every graph G in has an efficiently recognizable set of “contractible edges” (sometimes empty) such that a contraction minor belongs to if and only if F is a part of this set. So, the subclass of ante‐contraction members of plays a key role. Second, the members of have 3‐edge cuts. The familiar cactus representation of minimum edge cuts (Dinits et al., in: Issledovaniya po Diskretnoy Optimizatsii, Nauka, Moscow, pp. 290–306, 1976 (Russian); also A. Schrijver, Combinatorial Optimization (Polyhedra and Efficiency), Algorithms and Combinatorics, Vol. 24, Springer, 2003, p. 253) maps onto the class of trees whose internal vertices have even degrees, equal to 6 for any vertex adjacent to a leaf. The description of (quite concise as expressed in appropriate terms) refers to the explicit reconstruction of the reverse image of such a tree. We also derive the upper bound on the number of edges in an arbitrary n‐vertex ‐free graph, , and conjecture that its maximum equals .
The Number of Subtrees of Trees with Given Degree Sequence
Authors: Zhang Xiu‐Mei , Zhang Xiao‐Dong , Gray Daniel , Wang Hua
Published: August 2012

This article investigates some properties of the number of subtrees of a tree with given degree sequence. These results are used to characterize trees with the given degree sequence that have the largest number of subtrees, which generalize the recent results of Kirk and Wang (SIAM J Discrete Math 22 (2008), 985–995). These trees coincide with those which were proven by Wang and independently Zhang et al. (2008) to minimize the Wiener index. We also provide a partial ordering of the extremal trees with different degree sequences, some extremal results follow as corollaries.
Relations between ENSO and the South Atlantic SST modes and their effects on the South American rainfall
Authors: Kayano Mary T. , Andreoli Rita V. , Ferreira de Souza Rodrigo A.
Published: August 2012

This paper analyses the relations between the El Niño/Southern Oscillation (ENSO) mode in the tropical Pacific and the sea surface temperature (SST) modes in the South Atlantic for the 1900–2006 period. In the South Atlantic, two modes are analysed in more detail: the South Atlantic dipole (SAD) mode, with centres at (15°S, Greenwich longitude) and at (37.5°S, 25°W) and the southwestern South Atlantic (SWSA) mode, with centres at (30°S, 40°W) and at the southern midlatitudes. The ENSO and SAD modes are lagged or lead connected depending on the period of analysis. An El Niño (a La Niña) precedes by up to 6 months the establishment of a positive (negative) SAD mode during the 1920–1930 and 1940–1980 periods. Otherwise, a positive (negative) SAD mode precedes by up to 1 year the establishment of a La Niña (El Niño) during the 1975–2000 period. On the other hand, the SWSA is strongly driven by the ENSO. The effects of both the SAD and SWSA modes on the South American rainfall are also discussed on a seasonal basis. In general, the SAD (ENSO) mode has a weak influence on the ENSO‐related (SAD‐related) rainfall anomalies over South America. On the other hand, in general, the SWSA and ENSO modes have a combined effect on rainfall of the southern and southeastern regions of South America. A particularly important result of the present analysis for climate monitoring and forecasting purposes seems to be the changing relations between the SAD and ENSO modes. Copyright © 2012 Royal Meteorological Society
High‐anthocyanin strawberries through cultivar selection
Authors: Fredericks Charissa H , Fanning Kent J , Gidley Michael J , Netzel Gabriele , Zabaras Dimitrios , Herrington Mark , Netzel Michael
Published: August 2012

BACKGROUND: Diets high in fruit and vegetables are known to have significant health benefits. This is in part due to the presence of phytochemicals, which possess potential protective health benefits. This study focuses on the ability of strawberries to be bred for higher anthocyanin content. This is a major contributor to the characteristic colour and nutritional value of ripe strawberries, together with phenolic acids, ascorbic acid and total antioxidant capacity.

RESULTS: Anthocyanins in five commercial strawberry cultivars and three breeding lines were assessed. This led to the discovery of one breeding line (BL 2006‐221) as an exceptional source of anthocyanins (∼1 g kg−1 fresh weight), with approximately double the levels of current commercial cultivars. Temperature was shown to influence anthocyanin extraction, with 40 °C being the best extraction temperature using the accelerated solvent extraction (ASE) method. Hue angle and anthocyanin concentration showed a good correlation (r2 = 0.69).

CONCLUSION: The new breeding line BL 2006‐221 has the potential to be used in the development of phytochemically rich strawberry cultivars. Using hue angle as a screening tool for total anthocyanin concentration and extraction of anthocyanins from strawberries by ASE at 40 °C would support such cultivar development. © 2012 Commonwealth of Australia
An environmentally friendly and cost effective technique for the commercial cultivation of oyster mushroom [Pleurotus florida (Mont.) Singer]
Authors: Panjikkaran Seeja Thomachan , Mathew Deepu
Published: August 2012

BACKGROUND: The existing protocol for the cultivation of oyster mushroom (Pleurotus florida) in polyethylene bags leads to environmental pollution amounting to 18 g of polyethylene per 450 g of mushroom, which is the average biological efficiency achieved from a bag. Thus the projected annual global pollution amounts to 2 million tones, corresponding to the production of 48 million tones. Experiments were conducted at Kerala Agricultural University, India, to formulate an oyster mushroom cultivation strategy that reduces this pollution level.

RESULTS: Pooled results of experiments at the institute's and farmers' units have shown that reusable plastic buckets having perforations of 1.5 cm × 1.0 cm throughout the side walls could be used to substitute polyethylene bags, while following the standard cultivation protocols. Cultivation in perforated buckets has recorded a biological efficiency of 435.69 ± 56.75 g in 47.07 ± 5.22 days against 459.11 ± 53.52 g in 38.05 ± 4.54 days in polyethylene bags. The rate of contamination in buckets was significantly lower than that in bags: 9.28 ± 2.12 and 12.60 ± 3.73% respectively.

CONCLUSION: Reusable plastic buckets with perforations on the side walls could be used to substitute the conventional polyethylene bags in oyster mushroom cultivation, with no significant difference in yield. Losses due to slight increase in crop duration in buckets will be compensated with a lower rate of contamination. For a unit having a daily output of 100 kg, it was estimated that during 10 years of permanent cultivation following this technique, the cost of cultivation could be reduced to one‐tenth and the environmental pollution reduced by at least 730 000 non‐degradable polyethylene bags. © 2012 Society of Chemical Industry
Immunological determination of gliadin 33‐mer equivalent peptides in beers as a specific and practical analytical method to assess safety for celiac patients
Authors: Comino Isabel , Real Ana , de Lourdes Moreno Maria , Montes Raquel , Cebolla Ángel , Sousa Carolina
Published: August 2012

BACKGROUND: Cereals used for beer manufacturing contain gluten, which is immunotoxic for celiac patients. The gluten remaining after processes of malting and brewing is mostly hydrolyzed, which makes practical evaluation of the immunotoxicity of the gluten pools challenging.

RESULTS: We analyzed the presence of gluten peptides equivalent to the major immunotoxic protease‐resistant gliadin 33‐mer in 100 Belgium beers, using monoclonal antibodies (G12/A1). Immunochromatographic strips and enzyme‐linked immonosorbent assay G12/A1 methods estimated at least 20 ppm gluten equivalents in 90 beers and gluten‐free in 10 beers. The G12/A1 reactivity of beer high‐performance liquid chromatographic fractions correlated to the presence of T‐cell‐reactive epitopes identified by peptide sequencing.

CONCLUSION: The determination of equivalent gliadin 33‐mer epitopes in beers has been shown to be practical, specific, and sensitive for the measurement of potential immunotoxicity for celiac patients. Copyright © 2012 Society of Chemical Industry
Adjuvant therapy for pancreas adenocarcinoma
Authors: O'Reilly Eileen M.
Published: August 2012

Adjuvant therapy for pancreas adenocarcinoma in 2012 includes consideration of systemic therapy based on high level evidence and combined chemoradiotherapy based on less robust data. Current major adjuvant questions are examining the role of the addition of a second agent, either cytotoxic or targeted agent, to gemcitabine and whether or not the utilization of combined chemoradiotherapy improves overall survival. Progress to date has been modest and incremental in the adjuvant setting. J. Surg. Oncol. 2013;107:78–85. © 2012 Wiley Periodicals, Inc.
Podoplanin expression in cutaneous head and neck squamous cell carcinoma—prognostic value and clinicopathologic implications
Authors: Kreppel Matthias , Krakowezki Anton , Kreppel Barbara , Drebber Uta , Wedemeyer Inga , Mauch Cornelia , Zöller Joachim E. , Scheer Martin
Published: August 2012

Background

Although most patients are cured by local treatment from cutaneous head and neck squamous cell carcinoma (cHNSCC), a significant number of patients develops metastases to the regional lymph nodes. Recent studies suggest an influence of podoplanin expression on regional lymph node metastases in other head and neck squamous cell carcinoma. The aim of our study was to assess the impact of podoplanin expression on regional lymph node metastasis, locoregional recurrence, and prognosis.

Methods

In this retrospective study, podoplanin expression was examined immunohistochemically in 63 treatment‐naive patients with cHNSCC. We analyzed associations of podoplanin expression and clinicopathologic variables. Furthermore, we investigated the effects on overall survival (OS) and locoregional control in univariate and multivariate analysis.

Results

In 40 patients (63.5%), podoplanin was expressed in the tumor cells. The χ2‐test revealed that podoplanin expression was associated with the number of tumorous lymph nodes (P < 0.001). The OS was significantly influenced by podoplanin expression (P < 0.001). None of the patients with high levels of podoplanin expression survived, whereas the 5‐year OS for patients with podoplanin‐negative tumors was 91.3%.

Conclusions

We concluded that podoplanin is frequently expressed in cHNSCC and might serve as predictor for regional lymph node metastases, locoregional recurrence, and clinical outcome. J. Surg. Oncol. 2013;107:376–383. © 2012 Wiley Periodicals, Inc.
High‐temperature kinetics of the reaction between CN and hydrocarbons using a novel high‐enthalpy flow tube
Authors: Gardez Aline , Saidani Ghassen , Biennier Ludovic , Georges Robert , Hugo Edouard , Chandrasekaran Vijayanand , Roussel Vivien , Rowe Bertrand , Reddy K. P. J. , Arunan E.
Published: August 2012

More than 70 molecules of varied nature have been identified in the envelopes of carbon‐rich stars through their spectral fingerprints in the microwave or far infrared regions. Many of them are carbon chain molecules and radicals, and a significant number are unique to the circumstellar medium. The determination of relevant laboratory kinetics data is critical to keep up with the development of the high spectral and spatial resolution observations and of the refinement of chemical models. Neutral–neutral reactions of the CN radical with unsaturated hydrocarbons could be a dominant route in the formation of cyanopolyynes, even at low temperatures and deserve a detailed laboratory investigation. The approach we have developed aims to bridge the temperature gap between resistively heated flow tubes and shock tubes. The present kinetic measurements are obtained using a new reactor combining a high‐enthalpy source with a flow tube and a pulsed laser photolysis–laser‐induced fluorescence system to probe the undergoing chemical reactions. The high‐enthalpy flow tube has been used to measure the rate constant of the reaction of the CN radical with propane (C3H8), propene (C3H6), allene (C3H4), 1,3‐butadiene (1,3‐C4H6), and 1‐butyne (C4H6) over a temperature range extending from 300 to 1200 K. All studied reactions of CN with unsaturated hydrocarbons are rapid, with rate coefficients greater than 10−10 cm3 · molecule−1 · s−1 and exhibit slight negative temperature dependence above room temperature. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 753–766, 2012
Mechanical properties of porcine cartilage after uniform RF heating
Authors: Zemek Allison J. , Protsenko Dmitry E. , Wong Brian J.F.
Published: August 2012

Background and Objectives

Thermally mediated modalities of cartilage reshaping utilize localized heating of cartilage combined with mechanical deformation to achieve new geometries. We sought to determine the steady state elastic modulus of thermally modified cartilage without deformation, as this provides a constraint in mechanical models of the shape change process.

Study Design/Materials and Methods

The main objective of this study was to characterize the steady state elastic modulus of porcine septal cartilage after uniform heating with radiofrequency (RF) to peak temperatures of 50 ± 5, 65 ± 5, and 85 ± 5°C. The cartilage was divided into three equally sized regions, designated as anterior, middle and posterior. Each region was then sectioned into two specimens with the proximal component serving as a paired control.

Results

The data confirm that there is high baseline variability in control steady state elastic moduli between animals. Also, the control values confirm a decreasing steady state elastic modulus from anterior to posterior. There is no statistical significance (P > 0.05) found between the elastic moduli of control and treated samples.

Conclusions

Although shape change and retention have been fairly well characterized, little is known about the specific relation between steady state elastic modulus of cartilage and maximum treatment temperature. We determined that the difference of steady state elastic modulus between control and treated porcine septal samples was not statistically significant after uniform heating with RF to peak temperatures of 50 ± 5, 65 ± 5, and 85 ± 5°C. Ultimately, the results of this study do not pertain to the regions of heated cartilage that are shaped to hold a new form; however, it does show that the regions that are not mechanically deformed do return to the original pre‐treatment elastic modulus. This is still useful information that may be used in finite element models to predict changes in internal stress distributions of cartilage after laser reshaping. Lasers Surg. Med. 44: 572–579, 2012. © Wiley Periodicals, Inc.
The effects of low‐level laser therapy in a rat model of intestinal ischemia–reperfusion injury
Authors: Kirkby Kristin A. , Freeman David E. , Morton Allison J. , Ellison Gary W. , Alleman Arthur R. , Borsa Paul A. , Reinhard Mary K. , Robertson Sheilah A.
Published: August 2012

Background and Objective

To investigate the effects of low‐level laser therapy applied to the serosal surface of the rat jejunum following ischemia and reperfusion.

Materials and Methods

Ninety‐six male Sprague–Dawley rats were assigned to 15 groups and anesthetized. Small intestinal ischemia was induced by clamping the superior mesenteric artery for 60 minutes. A laser diode (70 mW, 650 nm) was applied to the serosal surface of the jejunum at a dose of 0.5 J/cm2either immediately before or following initiation of reperfusion. Animals were maintained under anesthesia and sacrificed at 0, 1, and 6 hours following reperfusion. Intestinal, lung, and liver samples were evaluated histologically.

Results

Intestinal injury was significantly worse (P < 0.0001) in animals treated with laser and no ischemia–reperfusion injury (IRI) compared to sham. Intestinal injury was significantly worse in animals that underwent IRI and laser treatment at all time points compared to sham (P < 0.001). In animals that underwent IRI, those treated with laser had significantly worse intestinal injury compared to those that did not have laser treatment at 0 (P = 0.0104) and 1 (P = 0.0015) hour of reperfusion. After 6 hours of reperfusion there was no significant difference in injury between these two groups. Lung injury was significantly decreased following IRI in laser‐treatment groups (P < 0.001).

Conclusions

At the dose and parameters used, low‐level laser did not protect against intestinal IRI in the acute phase of injury. However, laser did provide protection against distant organ injury. Failure to observe a therapeutic response in the intestine may be due to inappropriate dosing parameters. Furthermore, the model was designed to detect the histologic response within the first 6 hours of injury, whereas the beneficial effects of laser, if they occur, may not be observed until the later phases of healing. The finding of secondary organ protection is important, as lung injury following IRI is a significant source of morbidity and mortality. Lasers Surg. Med. 44: 580–587, 2012. © Wiley Periodicals, Inc.
Modification of Polycarbonate and Glycol Modified Poly(ethylene terephthalate) by Addition of Silica‐Nanoparticles Grafted with SAN Copolymer Using “Classical” and ARGET ATRP
Authors: Haase Andreas , Hesse Pascal , Brommer Lars , Jacobs Olaf , Abetz Clarissa , Handge Ulrich A. , Boschetti‐de‐Fierro Adriana , Abetz Volker
Published: August 2012

This study presents a nanocomposite manufacturing route starting from non‐functionalized nanosilica and SAN surface modification via “grafting from” ATRP up to processing of transparent polycarbonate and glycol modified poly(ethylene terephthalate) nanocomposites. Synthesis limitations of low molecular weight graft SAN derived from “classical” ATRP are overcome by employment of the emerging ARGET ATRP. Mechanical investigations of polycarbonate and glycol modified poly(ethylene terephthalate) nanocomposites present up to 80% enhancement of creep performance and additionally 70% enhancement against wear abrasion for glycol modified poly(ethylene terephthalate) nanocomposites. Strength and tensile modulus are only moderately influenced by the addition of nanoparticles. Morphological studies confirm that the present modification route is able to create uniform dispersions of single particles and small particle aggregates in polymer matrices.

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UV‐Cured Acrylic Conductive Inks for Microelectronic Devices
Authors: Sangermano Marco , Chiolerio Alessandro , Marti Giulio , Martino Paola
Published: August 2012

UV‐curable inks based on a poly(ethylene glycol) diacrylate (PEGDA) matrix and containing a dispersion of aqueous Ag nanoparticles in different amounts from 10 to 50% are prepared for the fabrication of inkjet printed resistors. The composition is adapted to the inkjet requirements in terms of viscosity, surface tension, and particle size. The gel content, glass transition temperature, conversion, UV‐Vis absorption, morphology, and DC electrical properties of the materials are characterized. It is found that the NPs dispersed in the polymeric matrix realize a percolating path by aligning themselves in chains, which results in a reduction of the percolation threshold. Thus, resistivity is well beyond the dissipative range.

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The Importance of Crosslinking and Glass Transition Temperature for the Mechanical Strength of Nanofibers Obtained by Green Electrospinning
Authors: Giebel Elisabeth , Getze Julia , Röcker Thorsten , Greiner Andreas
Published: August 2012

Crosslinked particles containing butyl acrylate, methyl methacrylate, and allyl methacrylate are prepared by free‐radical emulsion polymerization. The glass transition temperatures of the polymers are varied by the crosslinking densities in the latex particles. Aqueous acrylate dispersions with polymers of different glass transition temperatures are electrospun with PVA as the matrix polymer. The effects of crosslinking density and Tg on the structure and mechanical properties of the fibers are studied. Crosslinking of unreacted allyl groups is induced by UV irradiation to stabilize the fibers by interparticle crosslinking. Both the ability to undergo interparticle crosslinking and the E modulus depend on the merging of the particles during the electrospinning process.

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Open Drug Discovery Teams: A Chemistry Mobile App for Collaboration
Authors: Ekins Sean , Clark Alex M. , Williams Antony J.
Published: August 2012

The Open Drug Discovery Teams (ODDT) project provides a mobile app primarily intended as a research topic aggregator of predominantly open science data collected from various sources on the internet. It exists to facilitate interdisciplinary teamwork and to relieve the user from data overload, delivering access to information that is highly relevant and focused on their topic areas of interest. Research topics include areas of chemistry and adjacent molecule‐oriented biomedical sciences, with an emphasis on those which are most amenable to open research at present. These include rare and neglected diseases, and precompetitive and public‐good initiatives such as green chemistry. The ODDT project uses a free mobile app as user entry point. The app has a magazine‐like interface, and server‐side infrastructure for hosting chemistry‐related data as well as value added services. The project is open to participation from anyone and provides the ability for users to make annotations and assertions, thereby contributing to the collective value of the data to the engaged community. Much of the content is derived from public sources, but the platform is also amenable to commercial data input. The technology could also be readily used in‐house by organizations as a research aggregator that could integrate internal and external science and discussion. The infrastructure for the app is currently based upon the Twitter API as a useful proof of concept for a real time source of publicly generated content. This could be extended further by accessing other APIs providing news and data feeds of relevance to a particular area of interest. As the project evolves, social networking features will be developed for organizing participants into teams, with various forms of communication and content management possible.
Quantitative chemical exchange sensitive MRI using irradiation with toggling inversion preparation
Authors: Jin Tao , Kim Seong‐Gi
Published: August 2012

Chemical exchange (CE) sensitive MRI contrast acquired with an off‐resonance irradiation pulse is affected by other relaxation mechanisms, such as longitudinal and transverse relaxations. In particular, for intermediate CEs, the effect of transverse relaxation often dominates CE contrast. Since water relaxation rates can change significantly in many pathological conditions or during physiological challenge, it is crucial to separate these relaxation effects in order to obtain pure CE contrast. Here we proposed a novel acquisition scheme in which a toggling inversion pulse is applied prior to the off‐resonance irradiation. By combined acquisition of irradiation images with and without an inversion pulse at both the labile proton frequency and the reference frequency, longitudinal and transverse relaxation contributions are cancelled, and the quantification of CE parameters, such as the exchange rate and the labile proton concentration, can be simplified. Furthermore, the CE‐mediated relaxation rate can be readily determined with a relatively short irradiation pulse and without approaching the steady state, therefore, reducing the limitations on hardware and specific absorption rate requirements. The signal characteristics of the proposed method are evaluated by numerical simulations and phantom experiments. Magn Reson Med, 2012. © 2012 Wiley Periodicals, Inc.
Anterior tibialis cmap amplitude correlations with impairment in CMT1A
Authors: Komyathy Kelsey , Neal Stephanie , Feely Shawna , Miller Lindsey J. , Lewis Richard A. , Trigge George , Siskind Carly E. , Shy Michael E. , Ramchandren Sindhu
Published: August 2012

Introduction: CMT1A is the most common form of Charcot‐Marie‐Tooth disease (CMT), a slowly progressive neuropathy in which impairment is length dependent. Fibular nerve conduction studies to the anterior tibialis muscle (AT) may serve as a physiological marker of disease progression in patients with CMT1A. The objective of this study is to determine whether the AT compound muscle action potential (CMAP) amplitude correlates with impairment in patients with CMT1A. Methods: We correlated AT CMAP amplitudes and impairment measured by the CMT Neuropathy Score (CMTNS) in a cross‐section of 121 patients with CMT1A and a subset of 27 patients with longitudinal data. Results: AT CMAP amplitudes correlated with impairment as measured by the CMTNS in cross sectional analysis. Longitudinal changes in the AT CMAP showed a strong inverse correlation with leg strength but not other components of the CMTNS. Conclusions: AT CMAP amplitude may serve as a useful outcome measure for physiological changes in natural history studies and clinical trials for patients with CMT1A. Muscle Nerve, 2013
Discrete element modeling of tool‐rock interaction I: rock cutting
Authors: Huang H. , Lecampion B. , Detournay E.
Published: August 2012

Tool‐rock interaction processes can be classified as indentation or cutting depending on the direction of motion of the tool with respect to the rock surface. The modes of failure induced in the rock by an indenting or a cutting tool can be ductile and/or brittle. The ductile mode is associated with the development of a damage zone, whereas the brittle mode involves the growth of macrocracks. This is the first part of a series of two papers concerned with an analysis of the cutting and the indentation processes based on using the discrete element method. In this paper, numerical simulations of the cutting process are conducted to reproduce the transition from a ductile to a brittle failure mode with increasing depth of cut, which is observed in experiments. The numerical results provide evidence that the critical depth of cut d *  controlling the failure mode transition is related to the characteristic length ℓ = (KIc ∕ σc)2 with KIc denoting the material toughness and σc its unconfined compressive strength. The nature of frictional contact between the cutter face and the rock in the ductile failure mode is also examined. It is shown that the inclination of the total cutting force is controlled by a multi‐directional flow mechanism ahead of the cutter that is related to the formation of a wedge of failed material, intermittently adhering to the cutter. As a result, the inclination of the total cutting force varies with the rake angle of the cutter and cannot be considered an intrinsic measure of the interfacial friction between the cutter and the rock. Copyright © 2012 John Wiley & Sons, Ltd.
Effect of maleic anhydride grafting on nanokaolinclay reinforced polystyrene/high density polyethylene blends
Authors: George Tresa Sunitha , Krishnan Asha , Joseph Newly , Anjana R. , George K.E.
Published: August 2012

Nanofillers have revolutionized the field of polymer modification. Modification of polymer blends with nanofillers opens up a myriad of opportunities to develop materials of choice. Polystyrene (PS) and high density polyethylene (HDPE) are two widely used standard plastics. To generate high modulus and strength a PS rich blend of PS/HDPE (80/20) was selected and the blend was modified using low cost nanokaolin clay, a 1:1 alumina silicate. The effect of maleic anhydride grafted PS/PE as compatibilizer in this system was studied. The incorporation of the compatibilizer improves the mechanical properties. This can be correlated with better interfacial adhesion as evidenced by scanning electron microscopy. The optimum in these properties was obtained at a compatibilizer concentration of 10–15%. The composites were characterized byX‐ray diffraction, differential scanning calorimetric, and dynamic mechanical analyzer techniques. This study shows that kaolin can be used as potential modifier of PS/HDPE blend. POLYM. COMPOS. 2012. © 2012 Society of Plastics Engineers
The tensile behavior of off‐axis loaded plant fiber composites: An insight on the nonlinear stress–strain response
Authors: Shah Darshil U. , Schubel Peter J. , Clifford Mike J. , Licence Peter
Published: August 2012

Composites in load‐bearing applications are often exposed to off‐axis loads. For plant fiber composites (PFCs) to be seriously and readily considered in structural applications, knowledge and reliable prediction of their response to off‐axis loads is critical. This article (i) characterizes the stress–strain response, (ii) investigates the tensile properties, and (iii) analyses the fracture modes, of unidirectional flax‐polyester composites subjected to off‐axis tensile loading. A key finding of this study is that due to the nonlinear stress–strain response of PFCs, the apparent stiffness of the composite reduces by ∼30% in the strain range of 0.05 to 0.25%. In addition, through cyclic tests on the composites, the elastic strain limit is found to be only ∼0.15%. This has major implications on the strain range to be used for the determination of the composite elastic Young's modulus. Consequently, it is proposed that the tensile modulus for PFCs should be measured in the strain range of 0.025 to 0.100%. Through comparison with experimental data, conventional composite micromechanical models are found to be adequate in quantitatively describing the tensile behavior of off‐axis loaded PFCs. The application of such models has also enabled the determination of, otherwise difficult to measure, material properties, such as fiber shear and transverse modulus. Off‐axis loaded PFCs fail by three distinct fracture modes in three different off‐axis ranges; each fracture mode produces a unique fracture surface. POLYM. COMPOS. 2012. © 2012 Society of Plastics Engineers
Effect of organosilane coupling agents on microstructure and properties of nanosilica/epoxy composites
Authors: Yu Zhi‐Qiang , You Shu‐Li , Baier Horst
Published: August 2012

Three types of silane coupling agents, γ‐aminopropyltriethoxysilane, γ‐glycidoxypropyltrimethoxysilane, and γ‐methacryloxypropyltrimethoxysilane, were used as modifiers to modify the surface of the nanosilica, respectively, and the nanocomposites of the epoxy resin filled with nano‐sized silica modified by three silane coupling agents were prepared by physical blending. The properties of the modified silica nanoparticles were characterized by Fourier transform infrared spectrum and particle‐size analyzer. The microstructure, mechanical behavior, and heat resistant properties of the nanocomposites were investigated by transmission electron microscopy, scanning electron microscopy, thermo gravimetric analyses, differential thermal gravity, differential scanning calorimetry, and flexural tests. The results showed that these modifiers are combined to the surfaces of nanosilica by the covalent bonds, and they change the surface properties of nanosilica. The different structures of coupling agents have different effects on the dispersibility and stability of modified particles in the epoxy matrix. In comparison, the silica nanoparticles modified by γ‐glycidoxypropyltrimethoxysilane exhibit a good dispersivity. The nanocomposites with 4 wt% weight fraction nanosilica modified by γ‐glycidoxypropyltrimethoxysilane have higher thermal decomposing temperature and glass transition temperature than those of the other two composites with the same nanosilica contents, and they are raised by 43.8 and 8°C relative to the unmodified composites, respectively. The modified silica nanoparticles have good reinforcing and toughening effect on the epoxy matrix. The ultimate flexural strengths of the composites with 4 wt% nanoparticles modified by γ‐aminopropyltriethoxysilane, γ‐glycidoxypropyltrimethoxysilane, and γ‐methacryloxypropyltrimethoxysilane are increased by 10, 30, and 8% relative to the unmodified composites, respectively. The flexural fracture surfaces of modified composites present ductile fracture features. POLYM. COMPOS. 2012. © 2012 Society of Plastics Engineers
Abnormal increase of glass transition temperature of poly(propylene carbonate) modified with rubber particles
Authors: Wang Xiang , Li Zhuoxin , Cao Xingzhong , Wang Baoyi , Qi Guicun , Zhang Xiaohong , Gao Jianming , Li Binghai , Song Zhihai , Qiao Jinliang
Published: August 2012

Poly(propylene carbonate) (PPC) modified with CBS‐UFPR rubber particle was used as an example to explore the abnormal increase of glass transition temperature (Tg) of thermoplastics modified with rubber particle. TEM and AFM results showed that CBS‐UFPR was dispersed well in PPC with diameter of about 100 nm. The concentration and size of free‐volume in blends were measured by PALS, which indicated the existence of interfacial interaction between PPC and CBS‐UFRP. A schematic two‐layer model was proposed and the thickness of the interfacial layer was calculated. POLYM. COMPOS. 2012. © 2012 Society of Plastics Engineers
Unchanged prevalence of Down syndrome in the Netherlands: results from an 11‐year nationwide birth cohort
Authors: van Gameren‐Oosterom Helma B. M. , Buitendijk S. E. , Bilardo C. M. , van der Pal‐de Bruin Karin M. , Van Wouwe J. P. , Mohangoo A. D.
Published: August 2012

Objective

This study aims to evaluate trends in prevalence of Down syndrome (DS) births in the Netherlands over an 11‐year period and how they have been affected by maternal age and introduction of prenatal screening.

Method

Nationwide data of an 11‐year birth cohort (1997–2007) from the Netherlands Perinatal Registry were analyzed. First‐trimester combined screening was introduced in 2002, free of charge only for women 36 years of age or older and only on patients' request. Changes in maternal age, prevalence of DS births, and rates of births at <24 weeks (legal limit for termination of pregnancy in the Netherlands) during the study period were evaluated using logistic and linear regression analyses.

Results

In total, 1 972 058 births were registered (91% of the births in 1997–2007). Mean prevalence of DS was 14.57 per 10 000 births (95% confidence interval 14.43; 14.73); 85% of DS were live births. No significant trend in overall prevalence of DS births was observed (p = 0.385), in spite of a significant increase of mean maternal age during the same period (p < 0.001). The increased prevalence of DS births at ≥24 weeks among women ≥36 years of age (p = 0.011) was offset by a significant increase in the proportion of DS births at <24 weeks among women aged <36 years (p = 0.013).

Conclusion

The proportion of DS births in the Netherlands has not changed during the period 1997–2007. © 2012 John Wiley & Sons, Ltd.
Avoidant personality disorder
Authors: Maruta Toshimasa , Kato Masaaki , Matsumoto Chihiro , Iimori Makio
Published: August 2012

In this paper, we discuss avoidant personality disorder and its complexities by presenting a case in which the differential diagnosis was extremely difficult. The presented case concerns a patient, who initially received the diagnosis of ‘Taijin kyofusho’, a diagnosis commonly made in the traditional psychiatry in Japan, and later, his diagnosis was changed to avoidant personality disorder as the DSM‐III gained popularity. His chief complaint was his concern over his odour from his genitourinary organs, which led him to avoid interpersonal relationships. During the course of illness, his concern over his body odour and appearance grew to the extent that he sought surgical treatment, but he managed to succeed in his business. Currently, he is being treated with the medium dose of selective serotonin reuptake inhibitors in addition to psychotherapy, but his symptoms concerning interpersonal relationships still remain. Many symptoms other than typical ones of avoidant personality disorder were observed, and other psychiatric diagnoses, including delusional disorder, somatization disorder, and body dysmorphic disorder, were considered for differential diagnosis. Although they were ruled out in light of the criteria in the current diagnostic classification, this case illustrates the complex nature of the diagnosis of avoidant personality disorder, and furthermore, of psychiatric diagnoses. Copyright © 2012 John Wiley & Sons, Ltd.
A comprehensive full factorial LC‐MS/MS proteomics benchmark data set
Authors: Wessels Hans J. C. T. , Bloemberg Tom G. , van Dael Maurice , Wehrens Ron , Buydens Lutgarde M. C. , van den Heuvel Lambert P. , Gloerich Jolein
Published: August 2012

An important prerequisite for the development and benchmarking of novel analysis methods is a well‐designed comprehensive LC‐MS/MS data set. Here, we present our data set consisting of 59 LC‐MS/MS analyses of 50 protein samples extracted individually from Escherichia coli K12 and spiked with different concentrations of bovine carbonic anhydrase II and/or chicken ovalbumin, according to a 2 × 3 full factorial design. Using the well‐annotated and commonly used E. coli proteome as the sample background ensures that the complexity of the data is on a par with most current proteomic analyses. Data were acquired over a 2‐month period using multiple reversed‐phase columns and instrument calibrations to include real‐life challenges faced when analyzing large proteomics data sets. Moreover, so‐called “ground truth” data, comprised by LC‐MS/MS measurements of the pure spikes are included in the data set. The current manuscript elaborates this comprehensive benchmark data set for future development and evaluation of analysis methods and software.
Impairing the microRNA biogenesis pathway induces proteome modifications characterized by size bias and enrichment in antioxidant proteins
Authors: Peric Delphine , Labarre Jean , Chevalier François , Rousselet Germain
Published: August 2012

Perturbation of individual microRNAs, or of the microRNA pathway, plays a role in carcinogenesis. In certain cancer cells, inhibition of the microRNA biogenesis pathway leads to a growth arrest state (CoGAM for Colony Growth Arrest induced by Microprocessor inhibition), which can be rescued by re‐expression of individual microRNAs such as miR‐20a. We now report that inhibition of the microRNA biogenesis pathway induced proteome changes characterized by a size bias in differentially expressed proteins, with induction of small proteins and inhibition of large ones. This size bias was observed in cells undergoing CoGAM, as well as in CoGAM‐resistant cells, and in CoGAM‐sensitive cells rescued by miR‐20a. In this case, GO analysis of induced proteins identified by mass spectrometry revealed a significant enrichment in proteins involved in resistance to oxidative stress. In addition, H2O2 treatment of Saccharomyces cerevisiae or mammalian cells led to similarly size‐biased proteome modifications. Our results point to size bias as a relevant readout of proteome modifications, in particular in conditions of stress such as inhibition of the microRNA biogenesis pathway or oxidative stress. They also suggest research avenues to study the role of the microRNA pathway in proteostasis.
Toward the design of LPEI containing block copolymers: Improved synthesis protocol, selective hydrolysis, and detailed characterization
Authors: Tauhardt Lutz , Kempe Kristian , Schubert Ulrich S.
Published: August 2012

The synthesis of poly(2‐ethyl‐2‐oxazoline)‐b‐linear poly(ethylenimine) (PEtOx‐b‐LPEI) copolymers by selective basic hydrolysis of PEtOx‐b‐poly(2‐H‐2‐oxazoline) (PEtOx‐b‐PHOx) is described. For this purpose, an easy method for the preparation of the 2‐H‐2‐oxazoline (HOx) monomer was developed. Based on the microwave‐assisted polymerization kinetics for this monomer, PEtOx‐b‐PHOx copolymers were prepared. Subsequently, the block copolymers were selectively hydrolyzed to PEtOx‐b‐LPEI under basic conditions. The success of the polymerizations and subsequent post‐polymerization reactions was demonstrated by 1H NMR spectroscopy and MALDI‐TOF‐MS investigations of the obtained polymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012
Thermal Regime of a Cold Air Trap in Central Pennsylvania, USA: the Trough Creek Ice Mine
Authors: Edenborn Harry M. , Sams James I. , Kite J. Steven
Published: August 2012

Air temperatures internal and external to a talus cave (‘ice mine’) in central Pennsylvania were measured hourly for three years. Despite its location near the base of a talus slope, the cave demonstrated the thermal characteristics of an apparently static cave, with limited connections to the external environment other than through the cave entrance. Congelation ice that lasted until late spring formed as drip or flowstone and ponded ice from the limited influx of infiltrating water during late winter/early spring. A closed period of thermal stratification and slow warming of cave air was followed by an open period in winter months during which the cave was cooled by the influx of cold dry air. Unlike the occasionally strong and localised cooling induced by the flow of cold air from vents at the base of talus slopes, static cold traps retain their cold air and have little apparent effect on surrounding biota, instead providing potential refugia for organisms that prefer colder temperatures. Published 2012. This article is a U.S. Government work and is in the public domain in the USA.
RPGR mutations might cause reduced orientation of respiratory cilia
Authors: Bukowy‐Bieryłło Zuzanna , Ziętkiewicz Ewa , Loges Niki Tomas , Wittmer Mariana , Geremek Maciej , Olbrich Heike , Fliegauf Manfred , Voelkel Katarzyna , Rutkiewicz Ewa , Rutland Jonathan , Morgan Lucy , Pogorzelski Andrzej , Martin James , Haan Eric , Berger Wolfgang , Omran Heymut , Witt Michał
Published: August 2012

RPGR gene encodes retinitis pigmentosa guanosine triphosphatase regulator protein, mutations of which cause 70% of the X‐linked retinitis pigmentosa (XLRP) cases. Rarely, RPGR mutations can also cause primary ciliary dyskinesia (PCD), a multisystem disorder characterized by recurrent respiratory tract infections, sinusitis, bronchiectasis, and male subfertility. Two patients with PCD_RP and their relatives were analyzed using DNA sequencing, transmission electron microscopy (TEM), immunofluorescence (IF), photometry, and high‐speed videomicroscopy. The Polish patient carried a previously known c.154G>A substitution (p.Gly52Arg) in exon 2 (known to affect splicing); the mutation was co‐segregating with the XLRP symptoms in his family. The c.824 G>T mutation (p. Gly275Val) in the Australian patient was a de novo mutation. In both patients, TEM and IF did not reveal any changes in the respiratory cilia structure. However, following ciliogenesis in vitro, in contrast to the ciliary beat frequency, the ciliary beat coordination in the spheroids from the Polish proband and his relatives carrying the c.154G>A mutation was reduced. Analysis of the ciliary alignment indicated severely disturbed orientation of cilia. Therefore, we confirm that defects in the RPGR protein may contribute to syndromic PCD. Lack of ultrastructural defects in respiratory cilia of the probands, the reduced ciliary orientation and the decreased coordination of the ciliary bundles observed in the Polish patient suggested that the RPGR protein may play a role in the establishment of the proper respiratory cilia orientation. Pediatr Pulmonol. 2013; 48:352–363. © 2012 Wiley Periodicals, Inc.
Astrophysical evidence for the non‐Hermitian but PT‐symmetric Hamiltonian of conformal gravity
Authors: Mannheim P.D.
Published: August 2012

In this review we discuss the connection between two seemingly disparate topics, macroscopic gravity on astrophysical scales and Hamiltonians that are not Hermitian but PT symmetric on microscopic ones. In particular we show that the quantum‐mechanical unitarity problem of the fourth‐order derivative conformal gravity theory is resolved by recognizing that the scalar product appropriate to the theory is not the Dirac norm associated with a Hermitian Hamiltonian but is instead the norm associated with a non‐Hermitian but PT‐symmetric Hamiltonian. Moreover, the fourth‐order theory Hamiltonian is not only not Hermitian, it is not even diagonalizable, being of Jordan‐block form. With PT symmetry we establish that conformal gravity is consistent at the quantum‐mechanical level. In consequence, we can apply the theory to data, to find that the theory is capable of naturally accounting for the systematics of the rotation curves of a large and varied sample of 138 spiral galaxies without any need for dark matter. The success of the fits provides evidence for the relevance of non‐diagonalizable but PT‐symmetric Hamiltonians to physics.
Process hazard analysis for phases of operation in the process life cycle
Authors: Baybutt Paul
Published: August 2012

Processes experience various phases of operation during their life cycle. Hazard scenarios may occur during any of these phases, and they may vary by phase. Consequently, it is essential that process hazard analysis (PHA) studies address all phases of operation that a process may experience. Current PHA practices provide an inadequate treatment. This article describes an approach that provides an appropriate treatment for all process phases. © 2012 American Institute of Chemical Engineers Process Saf Prog, 2012