bluuebunny/crossref_metadata_2025 huggingface dataset:
Three new species of Navicula (Bacillariophyta) from lakes in Yunnan Plateau (China)
Authors: Gong Zhijun , Metzeltin Ditmar , Li Yanling , Edlund Mark
Published: May 2015

Three new freshwater diatoms are described from China’s Yunnan Plateau region in sediments from Lakes Fuxian, Erhai, and Lugu. Navicula craticuloides, nov. sp., N. gongii, nov. sp. and N. yunnanensis, nov. sp. were identified from light and scanning electron micrographs. The main features of N. craticuloides are its valve outline with rounded ends, a narrow-lateral raphe, hooked terminal fissures, a linear axial area, a rectangular central area, and wavy striae towards the margins. The main features of N. gongii are narrowly lanceolate valves with long-protracted ends, a lateral raphe, a slightly curved axial area, and a rhombic or transversely expanded central area. The main features of N. yunnanensis are lanceolate valves with triundulate margins and cuneate ends and a lateral raphe. The new species have so far been found mainly in surficial sediment.
Helping the Dying Patient and His Family
Authors: Wahl Charles William
Published: May 2015

As valuable as our physical help and education can be, it is the emotional interchange which we have with the dying patient and his family which is, in the long run, the most effective care. Through our capacity and willingness to comfort, reassure and enhearten we reaffirm to our patients and ourselves that we are also members of the human race and no less mortal than those we treat. The patient is oddly comforted by the finitude that we have in common.
A Unique Approach to Generate Self-Aligned SiO2/Ge/SiO2/SiGe Gate-Stacking Heterostructures in a Single Fabrication Step
Authors: Lai Wei-Ting , Yang Kuo-Ching , Hsu Ting-Chia , Liao Po-Hsiang , George Thomas , Li Pei-Wen
Published: May 2015

We report a first-of-its-kind, unique approach for generating a self-aligned, gate-stacking heterostructure of Ge quantum dot (QD)/SiO2/SiGe shell on Si in a single fabrication step. The 4-nm-thick SiO2 layer between the Ge QD and SiGe shell fabricated during the single-step process is the result of an exquisitely controlled dynamic balance between the fluxes of oxygen and silicon interstitials. The high-quality interface properties of our “designer” heterostructure are evidenced by the low interface trap density of as low as 2–4 × 1011 cm−2 eV−1 and superior transfer characteristics measured for Ge-based metal-oxide-semiconductor field-effect transistors (MOSFETs). Thanks to the very thin interfacial SiO2 layer, carrier storage within the Ge QDs with good memory endurance was established under relatively low-voltage programming/erasing conditions. We hope that our unique self-aligned, gate-stacking heterostructure provides an effective approach for the production of next-generation, high-performance Ge gate/SiO2/SiGe channel MOSFETs.
Flexible conducting polymer/reduced graphene oxide films: synthesis, characterization, and electrochemical performance
Authors: Yang Wenyao , Zhao Yuetao , He Xin , Chen Yan , Xu Jianhua , Li Shibin , Yang Yajie , Jiang Yadong
Published: May 2015

In this paper, we demonstrate the preparation of a flexible poly (3,4-ethylenedioxythiophene) -poly (styrenesulfonate)/reduced graphene oxide (PEDOT-PSS/RGO) film with a layered structure via a simple vacuum filtered method as a high performance electrochemical electrode. The PEDOT-PSS/RGO films are characterized by scanning electron microscopy (SEM), X-ray diffraction, Raman spectroscopy, and Fourier transform infrared (FT-IR) spectrometry. The results indicate that a layer-ordered structure is constructed in this nanocomposite during the vacuum filtering process. The electrochemical performances of the flexible films are characterized by electrochemical impedance spectroscopy, cyclic voltammetry, and galvanostatic charge/discharge. The results reveal that a 193.7 F/g highly specific capacitance of nanocomposite film is achieved at a current density of 500 mA/g. This flexible and self-supporting nanocomposite film exhibits excellent cycling stability, and the capacity retention is 90.6 % after 1000 cycles, which shows promising application as high-performance electrode materials for flexible energy-storage devices.
Synthesis and antitubercular evaluation of 7-chloro-4-alkoxyquinoline derivatives
Authors: Bispo Marcelle de Lima Ferreira , Cardoso Laura Nogueira de Faria , LourenÃ§o Maria C. S. , Bezerra FlÃ¡vio Augusto Ferreira Martins , Pinto Soares Rodrigo Pedro Pinto Soares , Bertollo Caryne Margotto , De Souza Marcus VinÃ­cius Nora
Published: May 2015

A series of eight 7-chloro-4-alkoxyquinoline derivatives (2a-h) have been synthesized and their in vitro (antimycobacterial) activity against Mycobacterium tuberculosis was evaluated. Â Furthermore, all the active compounds were selected for evaluation of their cytotoxicities against the human hepatoma (HepG2) and the relative selectivity (selective index) of these compounds against M. tuberculosis compared to HepG2 was calculated based on MLD50/MIC ratios. Â These biological results have been compared to a series of 7-chloro-4-aminoquinoline derivatives 1a-i, previously identified by our research group with the aim to provide important information about the structure-activity relationship of quinoline derivatives.
El impacto de las remesas en el crecimiento económico de América Latina, 1975-2012
Authors: Martín Mayoral Fernando , Proaño María Belén
Published: May 2015

La presente investigación analiza el efecto de las remesas en el crecimiento económico de los países de América Latina durante el período 1975-2012, controlando la posible endogeneidad de los regresores a través de estimadores GMM de sistema para modelos dinámicos de datos de panel. Los resultados muestran que no existe relación signi?cativa entre remesas y crecimiento económico en la mayor parte de países de América Latina, aunque su efecto sí es signi?cativo a partir de la crisis ?nanciera internacional de 2008. Por otro lado, el mayor crecimiento de las remesas se produce en aquellos países con un menor nivel de renta per cápita a corto plazo, lo que estaría evidenciando su carácter contracíclico y lo limitado de sus efectos al estar destinadas principalmente hacia el consumo.
Gobernanza de las aguas transfronterizas: fragilidades institucionales en América del Sur
Authors: Mello Sant’anna Fernanda , Villar Pilar Carolina
Published: May 2015

A partir de la década de 1990, la gobernanza ganó relevancia en la literatura sobre aguas transfronterizas, tal como la cooperación internacional entre los Estados ribereños. El presente trabajo pretende analizar cuáles son las fragilidades de la gobernanza de las principales cuencas transfronterizas en América del Sur, las Cuencas del Amazonas y del Plata. A pesar de la existencia de acuerdos internacionales, incluso para el desarrollo de infraestructuras y organismos supranacionales, la gobernanza del agua presenta fragilidades que se concentran en problemas institucionales, en la falta de participación y en la di?cultad de estructurar un proyecto común de desarrollo para esas aguas.
Las aguas subterráneas transfronterizas México-Estados Unidos: importancia e invisibilidad dentro del contexto del TLCAN
Authors: Hatch Kuri Gonzalo , Ibarra García María Verónica
Published: May 2015

Este artículo identifica la importancia del agua subterránea transfronteriza México-Estados Unidos, en relación con el vacío jurídico que predomina en su regulación en las diferentes escalas que intervienen en el uso, manejo y extracción de la misma y el significado de la escasez hídrica en la configuración del discurso hegemónico de seguridad nacional en el panorama neoliberal de integración regional del Tratado de Libre Comercio de América del Norte (TLCAN).
Inference for generalized exponential distribution based on generalized order statistics
Authors: Afify Eldesoky
Published: May 2015

Estimation of a parameter of generalized exponential distribution (gexp) is obtained based on generalized order statistics. The maximum likelihood and Bayes methods are used for this purpose. Survival function and hazard rate are also computed. Estimation based on upper record values from generalized exponential distribution is obtained as a special case and compared by simulated data.
Approximation operators by using finite family of reflexive relations
Authors: Abu-Donia Hassan , Salama Amgad
Published: May 2015

In this paper, we generalize the two types of Yao’s lower and upper approximations, using finite number of reflexive relations. Moreover, we give a comparison between these types and study some properties.
Taking IUPAC Literally: An International Union of Pure and Applied Chemistry
Authors: Seeman Jeffrey I.
Published: May 2015

This essay brings together two of the fundamental products of IUPAC, namely its international symposia and its official journal,
Twitter in Chemical Education, and IUPAC
Authors: @beardedchemist  , Hibbert D. Brynn
Published: May 2015

It is ironic that an article about Twitter, the quintessential social medium, should appear in a glossy print magazine for the benefit of the reading public. One might almost “lol” [1]. But all organisations are coming to grips (with more or less facility), with Facebook, Twitter, Instagram and all the paraphernalia of Web 2.0 [2]. The great movement to ‘open science’ is changing the way we communicate what we do.
Drug Design and Development: Part II: Reflections from an Academic-based Center
Authors: Erhardt Paul
Published: May 2015

As a follow-up to a previous issue of
Changes in cell death of peripheral blood lymphocytes isolated from children with acute lymphoblastic leukemia upon stimulation with 7 Hz, 30 mT pulsed electromagnetic field
Authors: Kaszuba-Zwoińska Jolanta , Ćwiklińska Magdalena , Balwierz Walentyna , Chorobik Paulina , Nowak Bernadeta , Wójcik-Piotrowicz Karolina , Ziomber Agata , Malina-Novak Kinga , Zaraska Wiesław , Thor Piotr J.
Published: May 2015

Pulsed electromagnetic field (PEMF) influenced the viability of proliferating in vitro peripheral blood mononuclear cells (PBMCs) isolated from Crohn’s disease patients as well as acute myeloblastic leukemia (AML) patients by induction of cell death, but did not cause any vital changes in cells from healthy donors. Experiments with lymphoid U937 and monocytic MonoMac6 cell lines have shown a protective effect of PEMF on the death process in cells treated with death inducers.The aim of the current study was to investigate the influence of PEMF on native proliferating leukocytes originating from newly diagnosed acute lymphoblastic leukemia (ALL) patients.

The effects of exposure to PEMF were studied in PBMCs from 20 children with ALL. PBMCs were stimulated with three doses of PEMF (7 Hz, 30 mT) for 4 h each with 24 h intervals. After the last stimulation, the cells were double stained with annexin V and propidium iodide dye to estimate viability by flow cytometric analysis.The results indicated an increase of annexin V positive as well as double stained annexin V and propidium iodide positive cells after exposure to threefold PEMF stimulation.

A low-frequency pulsed electromagnetic field induces cell death in native proliferating cells isolated from ALL patients. The increased vulnerability of proliferating PBMCs to PEMF-induced interactions may be potentially applied in the therapy of ALL.The analysis of expression of apoptosis-related genes revealed changes in mRNA of some genes engaged in the intrinsic apoptotic pathway belonging to the Bcl-2 family and the pathway with apoptosis-inducing factor (AIF) abundance upon PEMF stimulation of PBMCs.
Antioxidant effect of a fermented powder of Lady Joy bean in primary rat hepatocytes
Authors: Marca Margherita La , Pucci Laura , Bollini Roberto , Russo Rossella , Sparvoli Francesca , Gabriele Morena , Longo Vincenzo
Published: May 2015

The role and beneficial effects of plant and food extracts against various diseases induced by oxidative stress have received much attention in recent years. Legumes are rich in bioactive compounds, and some studies suggest a correlation between their consumption and a reduced incidence of diseases. Primary cultures of rat hepatocytes were used to investigate whether and how an extract obtained from a fermented powder of bean named Lady Joy (Phaseolus vulgaris L.) is able to regulate antioxidant and detoxifying enzymes through the NRF2 pathway, inhibit NF-kB activation, and reduce H
GGeneration of an efficient artificial promoter of bovine skeletal muscle alpha-actin gene (ACTA1) through addition of cis-acting element
Authors: Hu Qian , Tong Huili , Zhao Dandan , Cao Yunkao , Zhang Weiwei , Chang Shuwei , Yang Yu , Yan Yunqin
Published: May 2015

The promoter of skeletal muscle α-actin gene (ACTA1) is highly muscle specific. The core of the bovine ACTA1 promoter extends from +29 to −233, about 262 base pairs (bp), which is sufficient to activate transcription in bovine muscle satellite cells. In this study, analysis by PCR site-specific mutagenesis showed that the cis-acting element SRE (serum response element binding factor) was processed as a transcriptional activator. In order to enhance the bovine ACTA1 promoter’s activity, we used a strategy to modify it. We cloned a fragment containing three SREs from the promoter of ACTA1, and then one or two clones were linked upstream of the core promoter (262 bp) of ACTA1. One and two clones increased the activity of the ACTA1 promoter 3-fold and 10-fold, respectively, and maintained muscle tissue specificity. The modified promoter with two clones could increase the level of ACTA1 mRNA and protein 4-fold and 1.1-fold, respectively. Immunofluorescence results showed that green fluorescence of ACTA1 increased. Additionally, the number of total muscle microfilaments increased. These genetically engineered promoters might be useful for regulating gene expression in muscle cells and improving muscle mass in livestock.
Determination of Enthalpy of Pyrolysis from DSC and Industrial Reactor Data: Case of Tires
Authors: Lanteigne Jean-Remi , Laviolette Jean-Philippe , Chaouki Jamal
Published: May 2015

This study was motivated by the fact that differential scanning calorimetry (DSC)/differential thermal analysis (DTA) results in literature showed significant exothermic peaks while in overall, pyrolysis is an endothermic phenomenon. The specific heat of the decomposing tires has been determined with a new methodology: instead of assuming constant char properties throughout pyrolysis, the specific heat of evolving solids (char) was evaluated with increasing temperature and conversion. Measured specific heat values were observed to increase until pyrolysis was triggered at 250°C. Then, the specific heat of the solids decreased continuously until 400°C at which point they started to increase. This unexpected trend pointed out that the exothermic peak observed with DSC is an artefact generated by the control system of the apparatus. To overcome this limitation, the energy balance was performed over industrial data and the newly found heat capacity values. The enthalpy of pyrolysis was found to have a term dependent on the weight loss derivative, with a constant value of 410 kJ/kg tires. Two other terms for the enthalpy of pyrolysis have been identified, which were independent of weight loss. The first one is believed to correspond to the sulphur cross-link breakage at low temperature (65 kJ/kg), while the second one, at the final stage of pyrolysis, should correspond to charring reactions approaching the thermodynamic equilibrium (75 kJ/kg). Ultimately, this work proposes a new methodology to determine the enthalpy of pyrolysis with larger scale experimental data.
Xyngráphein – Historiographie und das Problem der Zeit. Überlegungen zum Muster der ‚Verdichtung’ in der europäischen Historiographie
Authors: Meier Mischa
Published: May 2015

Der Beitrag geht der Hypothese nach, dass narrative Geschichtswerke seit Thukydides (um 400 v. Chr.) in den Fällen, in denen die Autoren aus der Erfahrung einer existenziellen Bedrohungssituation heraus (z. B. durch Kriege) und mit besonderem affektiven Ausdruck schreiben, spezifische kompositionelle Muster erkennen lassen, die immer wiederkehren und den Historiographen mitunter auch unbewusst oder gar gegen ihre jeweilige Intention unterlaufen. Speziell für das Muster der zeitlichen Verdichtung wird diese Hypothese an exemplarischen Autoren der Vormoderne und der Moderne nachverfolgt: Thukydides, Orosius, Eduard Schwartz und Reinhart Koselleck.
Preparation and Characterization of Genipin-Crosslinked Chitosan Microspheres for the Sustained Release of Salidroside
Authors: Luo Mei , Peng Hailong , Deng Zhonghua , Yin Zhonghua , Zhao Qiang , Xiong Hua
Published: May 2015

Chitosan microspheres (CsMs) that encapsulate salidroside (Sal) were prepared by the emulsion crosslinking method with naturally occurring genipin (Gp) and then examined for their in vitro release. Sal-loaded CsMs (Sal-CsMs) showed nearly spherical and smooth surfaces with internal voids. The particle size of Sal-CsMs ranged within 0.56–5.01 μm, and their encapsulation efficiency and loading capacity were beyond 77.58% and 23.29%, respectively. The stability of Sal improved after entrapment into the CsMs. The release rate of Sal from CsMs was initially rapid, followed by sustained release. The release behavior depended on the pH of the release medium. The main release mechanisms underlying the release procedure were anomalous behavior and Fickian diffusion. These results indicated that CsMs with a novel crosslinker of Gp was a potential carrier system for producing functional foods containing Sal.
Inner harbour wave agitation using boussinesq wave model
Authors: Panigrahi Jitendra K. , Padhy C.P. , Murty A.S.N.
Published: May 2015

Short crested waves play an important role for planning and design of harbours. In this context a numerical simulation is carried out to evaluate wave tranquility inside a real harbour located in east coast of India. The annual offshore wave climate proximity- to harbour site is established using Wave Model (WAM) hindcast wave data. The deep water waves are transformed to harbour front using a Near Shore spectral Wave model (NSW). A directional analysis is carried out to determine the probable incident wave directions towards the harbour. Most critical threshold wave height and wave period is chosen for normal operating conditions using exceedence probability analysis. Irregular random waves from various directions are generated confirming to Pierson Moskowitz spectrum at 20m water depth. Wave incident into inner harbor through harbor entrance is performed using Boussinesq Wave model (BW). Wave disturbance experienced inside the harbour and at various berths are analysed. The paper discusses the progresses took place in short wave modeling and it demonstrates application of wave climate for the evaluation of harbor tranquility using various types of wave models.
Propensity Score Analysis with Survey Weighted Data
Authors: Ridgeway Greg , Kovalchik Stephanie Ann , Griffin Beth Ann , Kabeto Mohammed U.
Published: May 2015

Propensity score analysis (PSA) is a common method for estimating treatment effects, but researchers dealing with data from survey designs are generally not properly accounting for the sampling weights in their analyses. Moreover, recommendations given in the few existing methodological articles on this subject are susceptible to bias. We show in this article through derivation, simulation, and a real data example that using sampling weights in the propensity score estimation stage and the outcome model stage results in an estimator that is robust to a variety of conditions that lead to bias for estimators currently recommended in the statistical literature. We highly recommend researchers use the more robust approach described here. This article provides much needed rigorous statistical guidance for researchers working with survey designs involving sampling weights and using PSAs.
Was wir für Public Health haben und was uns noch fehlt
Authors: Räbiger Jutta , Borde Theda
Published: May 2015

Einleitung

In Forschung und Lehre ist Public Health in Deutschland gut aufgestellt. Auch als Politikberater haben Gesundheitswissenschaftler einen festen Platz erlangt. Was nach Ansicht der Autorinnen in Zukunft verstärkt werden müsste, ist die praktische Umsetzung von Public Health Maßnahmen (Epidemien wie Ebola haben die Defizite deutlich gemacht) und eine medienwirksame Öffentlichkeitsarbeit im weltweiten Verbund.
Die Medizinische Soziologie und Public Health
Authors: Koppelin Frauke , Babitsch Birgit
Published: May 2015

Dieser Beitrag widmet sich anhand der drei Themen, Soziale Ungleichheit und Gesundheit, Geschlecht und Gesundheit sowie Partizipation und Gesundheit, der Frage, welche möglichen Berührungspunkte als auch Unterschiede zwischen den Disziplinen Medizinische Soziologie und Public Health bestehen. Dabei wird deutlich, welchen Erkenntnisbeitrag die Medizinische Soziologie und/oder Public Health für das Verständnis von Gesundheit und der Gesundheitsversorgung geleistet haben bzw. leisten.
Möglichkeiten und Grenzen der Gesundheitsökonomie: Wettbewerb
Authors: Greß Stefan
Published: May 2015

Einleitung

Aus gesundheitsökonomischer Sicht ist der Wettbewerb der Krankenkassen untereinander ein wichtiges Steuerungsinstrument, um die Gesundheit der Bevölkerung zu verbessern. Die Erfolge sind jedoch bisher begrenzt. Krankenkassen haben in einem wettbewerblichen System zudem wenige Anreize, um in langfristig wirksame Maßnahmen von Prävention und Gesundheitsförderung zu investieren. Krankenkassen bieten daher vor allem solche Maßnahmen an, die kurzfristig im Sinne von Marketingmaßnahmen wirksam sind.
Patientenorientierung ernst nehmen
Authors: Braun Bernard , Klemperer David
Published: May 2015

Einleitung

Die Orientierung an und auf die Bedarfe, Bedürfnisse und Präferenzen von Patienten gehört seit vielen Jahren zum Basisrepertoire der Gesundheitsrhetorik. Trotz einiger praktischer Schritte in diese Richtung, sieht der Alltag im deutschen Gesundheitswesen aber noch deutlich anders aus. Erst wenn Versorgungsforscher, gesundheitspolitisch Verantwortliche und Versorgungspraktiker Patientenorientierung zum archimedischen Punkt ihrer Sicht- und Handlungsweise machen, wird sich daran etwas ändern.
Die Impfmüdigkeit in Deutschland: Eine potenzielle Bedrohung für uns alle?!
Authors: Hofmann Friedrich
Published: May 2015

Einleitung

Die Durchführung von Impfungen ist eine erfolgreiche Maßnahme zur Kontrolle von Infektionskrankheiten. In Deutschland werden von der Ständigen Impfkommission am Robert Koch-Institut (STIKO) derzeit 15 Standard- und 7 Indikationsimpfungen empfohlen. Immunisierungslücken können zur Weiterverbreitung gefährlicher Pathogene führen und stellen damit ein Risiko für die Gesellschaft dar, da nicht alle Personen (z.B. Neugeborene) geimpft werden können. Deshalb müssen hohe Durchimpfungsraten erreicht werden, um Infektionserreger kontrollieren und eradizieren zu können.
Inklusion älterer und gesundheitlich eingeschränkter Arbeitnehmer in der Arbeitswelt
Authors: Hodek Lene , Niehaus Mathilde
Published: May 2015

Einleitung

Mit Unterzeichnung der UN-BRK verpflichtet sich Deutschland, die Rechte von Menschen mit Behinderung zu achten. Der Arbeitsmarkt soll offen und inklusiv gestaltet werden, zudem besteht ein Recht auf sichere und gesunde Arbeitsbedingungen. Bislang wird dies nicht in allen Unternehmen gewährleistet. Durch die verbesserte Zusammenarbeit von Arbeitnehmern, Unternehmen und Sozialversicherungsträgern soll es ermöglicht werden, frühzeitig potenzielle Gefährdungen der Beschäftigungsfähigkeit zu erkennen und die berufliche Inklusion gesundheitlich beeinträchtigter Beschäftigter zu sichern. Dies auch vorrangig mit dem Ziel die Beschäftigungsfähigkeit älterer Arbeitnehmer dauerhaft zu erhalten.
Germany’s global health policy
Authors: Razum Oliver , Karrasch Laura , Zeeb Hajo
Published: May 2015

Einleitung

2013 veröffentlichten fünf Bundesministerien erstmals ein gemeinsames Konzeptpapier zu Deutschlands internationaler Gesundheitspolitik. Trotz dieses positiven Schritts bleibt Klärungsbedarf: Die Rolle der Pharmaindustrie wird genauso unzureichend spezifiziert wie die Mechanismen der Zusammenarbeit zwischen den beteiligten Ministerien. Globale Gesundheit beginnt im eigenen Land: Das Konzeptpapier sollte sich eingehender mit einer menschenwürdigen Flüchtlingsstrategie für alle EU-Länder beschäftigen.
Impact response characterization of shear CFRP strengthened RC beams by Fourier and wavelet methods: tests and analyses
Authors: Shafei Erfan
Published: May 2015

The current experimental study investigates impact response features of reinforced concrete (RC) beams with dominant shear failure mode. Six built nonstrengthened and strengthened RC beams with a shear span-to-depth ratio of 2.5 were subject to repeated low-velocity impacts. Projectile energy is equal to the amount required for collapse. Retrofit consists of carbon fiber-reinforced polymer (CFRP) sheets attached to the exterior surface in vertical-unidirectional and cross-ply orientation. Laser linear variable differential transformer (LVDT) and micro-electro-mechanical systems (MEMS) accelerometers record the resultant deflection and acceleration to inspect the relationship between retrofit and damage. Fast Fourier transform (FFT) and continuous wavelet transform (CWT) extract the response content specimens to monitor the frequency change for each case. According to extracted results, CFRP skin provides notable stiffness on the upward shift of active frequency range and peak spectrum amplitude maintained for impact repeats. The active domain in FFT spectrum is sensitive to failure type (shear or flexural). CWT analysis ridges show a clear difference between failure type samples. CFRP retrofit controls cracking and deflection, which is shown as increased acceleration in records, especially for the cross-ply wrap. Effective stiffness recovers during initial impacts and then starts degrading because of the rupture of horizontal fibers in cross-ply retrofit, but the stiffness is stable for unidirectional retrofit during all impacts.
Study Microstructure and Mechanical Properties of Prosthesis of Forging
Authors: Rojas-Olmos D. C. , López-Perrusquia N. , Doñu-Ruiz M. A. , Juanico Loran J.A , Torres San Miguel C. R.
Published: May 2015

This work studies the change microstructural and mechanical properties of biomedical component hot forging of titanium; was assessed quantitatively and qualitatively the microstructural features obtained in this titanium biocompatible Ti6Al4V. The forging process was obtained at temperature of 950 °C, after by technical optical microscopy are obtained the microstructural characterization showing the phases present after forging. Likewise, the technical X-ray diffraction (XRD) shows the presence of the phases. Also is evaluated the hardness and modulus of elasticity by technical nanoindentation. The characterization of this material has the objective to show that the results obtained with temperature study of 950 °C. Likewise by the forging process obtained a type phases and optimal properties required for these biomedical materials.
Characterization of Mg AZ31 Alloy ECASD Processed Using Dynamical Mechanical Analysis (DMA)
Authors: Peláez Daniel , Restrepo-Osorio Adriana , Mendoza Emigdio , Isaza Cesar , Fernandez-Morales Patricia
Published: May 2015

In the present work was used Dynamical Mechanical Analysis (DMA) to study the magnesium alloy Mg AZ31-B, in plate form with a thickness of 2.5 mm. The plates were processed using Equal Channel Angular Sheet Drawing (ECASD), which is a severe plastic deformation technique, which allows imposing strain without dimensional changes to a metal plate, at room temperature with an angle of 135°. The obtained results show dependence between the storage modulus (M’), temperature and frequency used on the tests. The greater M’ values were obtained at the lower temperatures and at the higher frequency used. However, at lower frequencies M’ response is not affected by the used frequencies. At the higher temperatures there is an M’ reduction, which promotes the material deformation.
Physicochemical Properties of Vitrified Forms for LILW Generated From Korean Nuclear Power Plant
Authors: Kim Cheon-Woo , Lee Hyehyun , Jang In-Sun , Jo Hyun-Jun , Cho Hyun-Je
Published: May 2015

Since 1994, the KHNP has developed a vitrification technology to treat the LILW generated from Korean nuclear power plant. To vitrify the LILW including combustible Dry Active Waste (DAW) and Ion Exchange Resin (IER) containing Zeolite, two borosilicate glasses are formulated. One of the formulated glass, DG2, is for the DAW vitrification solely and the other one, AG8W1, is for the blended wastes (DAW & IER) vitrification in a commercial vitrification facility in HanUl (former Ulchin) nuclear power plant. The physicochemical properties of the two glasses have been evaluated. To evaluate the processability of the glasses, the viscosities and electrical conductivities of the glass melts were measured in the laboratory within a temperature range between 950 and 1,350 degrees C, respectively. The liquidus temperatures of the glasses were evaluated using a gradient furnace for DG2 and data from heat treatment for AG8W1. The Mössbauer spectroscopy for AG8W1 was employed to evaluate the relations between the redox equilibria of iron. In addition, to verify the waste acceptance criteria for the final disposal of the vitrified forms, the compressive strengths of the vitrified forms were tested after an immersion test, a thermal cycling test, and an irradiation test. To verify the chemical durability of the glasses, several tests such as PCT, ISO, VHT, Soxhlet, MCC-1, and ANS16.1 were carried out. The PCT showed leach rates of B, Na, Li and Si were much less than those of the benchmark glass. The ISO test was performed at 90 degrees C for 1,022 days and Cumulative Fraction Leached of all elements in the glasses were analyzed. According to the VHT, the glasses had an outstanding chemical resistance under humid environment at 200 degrees C for 7 days. The Soxhlet leaching was performed on rectangular glass samples at 98 degrees C for 30 days. To analyze the forward dissolution rates of major glass elements, the MCC-1 was conducted at temperatures of 40, 70, and 90 degrees C for three weeks in pH buffer solutions ranging from pH 4 to 11. The processability of the glasses was in the desired ranges. And the product quality of the glasses met all regulatory guidelines. Using two glasses, the CCIM commissioning tests in the UVF were successfully performed and they showed good workability.
Physical Mechanisms Affecting the Reliability of GaN-based High Electron Mobility Transistors
Authors: Schrimpf R. D. , Fleetwood D. M. , Pantelides S. T. , Puzyrev Y.S. , Mukherjee S. , Reed R. A. , Speck J. S. , Mishra U. K.
Published: May 2015

The physical mechanisms responsible for electrically-induced parametric degradation in GaN-based high electron mobility transistors are examined using a combination of experiments, device simulation, and first-principles defect analysis. A relatively simple formulation is developed under the assumption that the hot-electron scattering cross-section is independent of the electron energy. In this case, one can relate the change in defect concentration to the operational characteristics of a device, such as the spatial and energy distribution of electrons (electron temperature), electric field distribution, and electron energy loss to the lattice.
Crystal Growth of CdTe2O5 by a Modified Bridgman Technique
Authors: Nawash Jalal
Published: May 2015

The growth of CdTe2O5 single crystals using a modified Bridgman technique in a RF furnace was attempted. A platinum/gold crucible was used to melt the powder mixture in a customized insulated chamber to provide an adequate vertical thermal gradient. Growths resulted in mica-shaped single crystals that were extracted and investigated. Some optical and electrical properties were studied. Czochralski (CZ) method was also tried but returned very small crystals at best, whereas evaporation of CdO and/or TeO2 presented another challenge.
Extracting Mobility-Lifetime Product in Solar Cell Absorbers Using Quantum Efficiency Analysis
Authors: Poindexter Jeremy R. , Brandt Riley E. , Mangan Niall M. , Buonassisi Tonio
Published: May 2015

The long-wavelength quantum efficiency (QE) response of photovoltaic absorbers is determined by the length scales for minority carrier collection. However, extracting quantitative measurements of minority carrier mobility-lifetime product (μτ) is complicated by uncertainty in other factors such as the depletion width, electric field, and the absorption coefficient. We apply previously developed methods to obtain estimates for μτ in a tin(II) sulfide (SnS) solar cell. We compare three analytic models for the minority carrier collection probability as a function of absorber depth to determine which model most accurately captures the behavior in our devices. For models in which multiple parameters are unconstrained, a random numerical search is used to optimize the fit to experimental QE for SnS. To identify sources of error, we perform a sensitivity analysis by fitting with SCAPS-1D. Our analysis shows that changes in absorption most strongly affect estimates for μτ, highlighting the need to obtain accurate, device-specific absorption data. Further modeling and experimental constraints are required to obtain self-consistent values for μτ that correspond to actual device performance.
Influence of glycidylmethacrylate functional groups attached to gelatin on the formation and properties of hydrogels
Authors: Löwenberg Candy , Julich-Gruner Konstanze K. , Neffe Axel T. , Lendlein Andreas
Published: May 2015

Gelatin functionalized with glycidyl methacrylate (GMA) has been shown to allow crosslinking by photopolymerization and metathesis reaction. However, side chain functionalization of gelatin might reduce triple helicalization, which influences mechanical properties of gelatin-based polymer networks. Here, the influence of glycidylmethycrylation of gelatin on the chain organization, swelling, and mechanical properties is investigated by comparing among each other physical gels prepared from GMA-gelatin solutions of different concentrations (5-20 wt.-%) by drying and rehydration. An increase of GMA-gelatin concentration from 5 wt.-% to 20 wt.-% led to an increased density of produced gelatin films and a decreasing water uptake of the films from 1160 wt.-% to 730 wt.-%, while the storage modulus was increasing about one order of magnitude from 440 Pa to 4090 Pa. The relative single and triple helix content was not influenced by the variation of polymer concentration.
Anisotropic Composites of Desaminotyrosine and Desaminotyrosyl Tyrosine Functionalized Gelatin and Bioactive Glass Microparticles
Authors: Julich-Gruner Konstanze K. , Lendlein Andreas , Boccaccini Aldo R. , Neffe Axel T.
Published: May 2015

Functionalization of gelatin with desaminotyrosine (DAT) and desamino tyrosyl tyrosine (DATT) has been demonstrated to allow network formation based on non-covalent interactions of the aromatic moieties. Based on the observation that the DAT(T) groups furthermore could interact with hydroxyapatite fillers, here it was investigated whether such interactions of DAT(T) could also be employed to stabilize composites formed by functionalized gelatins and bioactive glass (BG) particles. Because of sedimentation of the BG microparticles during the gelification, anisotropic composites with two distinct layers were formed. The characterization of mechanical properties by tensile tests and rheology showed that all composites of non-functionalized and DAT(T) functionalized gelatins with BG microparticles showed an increased Young’s modulus (E) up to 3 MPa, an increased storage modulus (G’) up to 100 kPa, increased tensile strength (σmax) up to 3.4 MPa, and increased loss modulus (G’’) compared to the pure matrices. As the observed effects were more pronounced in the DAT(T) functionalized gelatins compared to non-functionalized gelatins, and a much increased thermal stability of these composites was found, it is likely that there are binding interactions between the aromatic moieties and the BG microparticles. This effect open opportunities for the further development of this type of gelatin-based composites for bone regeneration applications.
Psychological First Aid
Authors: Ruzek Josef I. , Brymer Melissa J. , Jacobs Anne K. , Layne Christopher M. , Vernberg Eric M. , Watson Patricia J.
Published: May 2015

Psychological First Aid (PFA) consists of a systematic set of helping actions aimed at reducing initial post-trauma distress and supporting short- and long-term adaptive functioning. Designed as an initial component of a comprehensive disaster/trauma response, PFA is constructed around eight core actions: contact and engagement, safety and comfort, stabilization, information gathering, practical assistance, connection with social supports, information on coping support, and linkage with collaborative services. PFA for children and adolescents focuses on these same core actions, with modifications to make them developmentally appropriate. Formal evaluation of the effectiveness of PFA is needed and it is hoped that development of a PFA Field Operations Guide will facilitate such evaluation.
Clinician Perspectives of the Therapeutic Use of the Self-confrontation Procedure with Suicidal Clients
Authors: Popadiuk Natalee , Young Richard A. , Valach Ladislav
Published: May 2015

This research investigated clinician perspectives of the therapeutic use of the self-confrontation procedure with suicidal clients. The self-confrontation procedure, which involves the use of video playback of interviews with clients who have experienced suicidal ideation and attempts, has previously been used for research purposes. The current research sought to build on the use of the self-confrontation procedure by asking mental health clinicians how they might use the method in a therapeutic context. These professionals developed an understanding of the procedure through experiential activities, practice, readings, and discussion. They first identified the challenges in working with suicidal clients, and then developed ideas about how the self-confrontation method could be useful in overcoming these challenges.
Contemporary Issues in Private Practice: Spotlight on the Self-Employed Mental Health Counselor
Authors: Harrington Judith
Published: May 2015

Mental health counselors (MHCs) are employed in a variety of professional settings, among them community agencies, schools, colleges and universities, hospitals, clinics, treatment centers, government, military, employee assistance programs, insurance or managed care companies, and private practice. Arguably, private practice is the setting where the potential for career gratification and self-direction is most counterbalanced by vocational and financial vulnerability. This article introduces the Special Issue of the Journal of Mental Health Counseling (JMHC), Contemporary Issues in Private Practice, and highlights the paucity of scholarly literature dealing with private practice; recalls the historic challenges between the research and clinical communities related to field-based research and collaboration and accurately quantifying the actual number of private practitioners; and reflects on the recent past and future of private practice counseling.
Controlling Losses When Recompleting Low-Pressure Reservoirs
Authors: Uguna G. , Rachid R. , Milne A. , Ali S.
Published: May 2015

The challenge in many permeable water sensitive subhydrostatic reservoirs is to avoid the loss of completion fluid when completing or working over wells. It is not unusual to lose up to 1,000 bbl of completion fluid, resulting in a 20% to 50% reduction in production.

Several different approaches have been used to prevent these losses. The most common is viscous fluid-loss control pills with sized particulates, such as calcium carbonate, which often requires a further treatment to remove the solids. An alternative is a solids-free crosslinked viscous polymer pill, which must be spotted and kept in position across the reservoir prior to it crosslinking.

To overcome the limitation of conventional fluid-loss control pills, a low-viscosity system was developed. The system is composed of a viscous disproportionate permeability modifier (VDPM) with sized synthetic polymer particles and fibers, which, with time and temperature, degrade into organic acids. The VDPM reduces the effective permeability to the water-based fluids, and the sized particles create an impermeable filter cake. When the particles degrade, the organic acid acts to break any remaining polymer. The system can either be bullheaded or spotted in the wellbore prior to perforating and effectively seals the formation for several days.

The fluid-loss pill has been used successfully in more than 25 wells. The volume of fluid lost into the formation is often less than 1 bbl, and production is maintained after the workover. The technique has made it possible to selectively stimulate new intervals or recomplete wells with an average increase of more than 240 BOPD, whereas, historically, a decline in production was not uncommon.
Injectivity during PWRI and Disposal in Thick Low Permeable Formations (Laboratory and Mathematical Modelling, Field Case)
Authors: Kalantariasl Azim , Schulze Kai , Storz Jöerg , Burmester Christian , Kuenckeler Soeren , You Zhenjiang , Badalyan Alexander , Bedrikovetsky Pavel
Published: May 2015

Produced water management is a growing challenge for oil and gas industry. Over the last decade, the scale of produced water re-injection (PWRI) and disposal in petroleum industry has increased tremendously. PWRI is an important economic and environmental-friendly option to convert waste to value with waterflooding. Nevertheless, drastic decline of injectivity, widely reported in the literature, restricts the project efficiency. In the present work, laboratory coreflood test using low permeable core sample is performed to investigate the impedance (normalised reciprocal of injectivity) behaviour. Analytical model for well impedance growth, along with probabilistic histograms of injectivity damage parameters, is applied to the well injectivity decline prediction during produced water disposal in a thick low permeable formation (Völkersen field). Unusual convex form of impedance curve is observed in both laboratory coreflooding and well behaviour modelling. Impedance grows slower during external cake formation compared to that during deep bed filtration. This is due to low reservoir permeability and consequent high values of filtration and formation damage coefficients causing fast impedance growth during deep bed filtration; while external cake build-up yields relatively slower impedance growth during cake formation. Risk analysis method using probabilistic histograms of injectivity damage parameters is applied to well behaviour prediction under high uncertainty conditions.
Role of Well Completion in PWRI design
Authors: Ochi Jalel , Hofsaess Thomas
Published: May 2015

Before any Produced Water Re-Injection (PWRI) project, specifications of water quality in terms of solid and oil contents must be determined to allow designing water treatment facilities. Also, specifications of injection pressure must be determined to allow designing injection pumps and network. An incorrect design may lead to significant injectivity declines, to injection volumes below target and therefore to loss of production. These specifications are usually provided by considering re-injection in fracturing flow regime because it is the only regime that can sustain the injectivity of wells on the long term. However, even if the matrix flow period which precedes the fracture initiation is also fundamental in determining these specifications, it currently remains considered in only very few commercial softwares.

It is fundamental to model the matrix flow period especially in terms of damage mechanisms. Indeed, this period can be of relatively long duration and can dominate the well behavior before the initiation of any fracturing. For example, this is the case of gas fields where only small volumes of water are produced during the first years of production. Taking into account this period can also help in optimizing water quality and pressure specifications by selecting the most appropriate completion for wells. In fact, the same water quality could lead to different damage potentials and thus to different fracturing pressures inititation that depend on the well completion scheme selected, whether open hole (OH) or cased and perforated (CP).

Even if a lot of models dealing with formation damage already exist for oil and gas producers, only very few models are available for CP water injectors. This paper presents a new model which allows simulating formation damage occurring while injecting in this type of wells. This model extends the standard CP calculations with the modeling approaches for external and internal damage which have already been available in Total's in-house simulator for OH completions. This paper also presents how water quality and injection pressure specifications are predicted for CP wells, the key parameters in perforation strategy to optimize them and why these specifications differ from one completion to the other. Finally, an example of field application of the model to design of PWRI project in a CP disposal well will be discussed.
Customized Sealants for Water/Gas Shutoff Operations in Horizontal and Highly Deviated Wellbore Completions
Authors: Eoff Larry , Vasquez Julio , Recio Antonio , Reddy B. R. , Pascarella Natalie
Published: May 2015

Horizontal wellbores can present unique problems during water and gas shutoff operations. The primary challenges include the extended length of many horizontal wells, which could be outside the reach of coiled tubing (CT), and the fact that many are completed with open holes, gravel packs, or slotted liners. With gravel pack and slotted liner completions, it can be extremely difficult, if not impossible, to obtain complete zonal isolation. Even when the offending water or gas producing zones are clearly demarcated from the producing zones, chemical remediation remains arduous. Mechanical plugs can be set inside gravel pack screens or slotted liners and a chemical sealant can be pumped into this isolated internal section. However, it is difficult to limit fluid flow in the outer annular space. Because most chemical sealants are designed to have relatively low viscosity, they tend to slump to the low side of the wellbore, either inside or outside of this isolated section. Consequently, the water and/or gas zones are not uniformly exposed to the treatment, which could result in an incomplete seal. Because more horizontal wells are being drilled, water/gas shutoff systems are necessary for these types of completions. An ideal sealant system would exhibit flow properties facilitating pumping and placement while, immediately upon placement in the desired location, resist slumping by behaving as a thick paste.

This paper presents three systems designed to address the challenges associated with treatment of zones within horizontal wellbores. The objective was to develop sealant systems that would not slump upon placement and subsequently undergo polymerization, crosslinking, or setting and provide lasting seals to prevent water/gas flow. The fluids discussed include polymeric and monomeric gels and a Sorel cement based system, which additionally contains additives to provide slump resistant properties. The chemistries that impart the slump resistant properties are discussed. In addition, laboratory data is presented to include slump measurements, gelation times, and flow resistance measurements.