bluuebunny/crossref_metadata_2025 huggingface dataset:
Graphynes: an alternative lightweight solution for shock protection
Authors: Xia Kang , Zhan Haifei , Ji Aimin , Shao Jianli , Gu Yuantong , Li Zhiyong
Published: July 2019

The excellent mechanical properties of graphyne (GY) have made it an appealing candidate in the field of impact protection. We assessed the deformation mechanisms of monolayer GY nanosheets of different morphologies, including α-GY, β-GY, γ-GY and 6612-GY, under supersonic-velocity impacts (from 1 to 6 km/s) based on in silico studies. Generally, cracks initiate at the geometry center and the nanosheet experiences significant out-of-plane deformation before the propagation of cracks. Tracking the atomic von Mises stress distribution, it is found that its cumulative density function has a strong correlation with the magnitude of the Young’s modulus of the GYs. For nanosheets with a higher Young’s modulus, it tends to transfer momentum at a faster rate. Thus, a better energy dissipation or delocalization is expected during impact. This study provides a fundamental understanding of the deformation and penetration mechanisms of monolayer GY nanosheets under impact, which is crucial in order to facilitate their emerging applications for impact protection.
Magnetic Inflation and Stellar Mass. III. Revised Parameters for the Component Stars of NSVS 07394765
Authors: Healy Brian F. , Han Eunkyu , Muirhead Philip S. , Skiff Brian , Polakis Tom , Rilinger Anneliese , Swift Jonathan J.
Published: July 2019

We perform a new analysis of the M-dwarf–M-dwarf eclipsing binary system NSVS 07394765 in order to investigate the reported hyper-inflated radius of one of the component stars. Our analysis is based on archival photometry from the Wide Angle Search for Planets, new photometry from the 32 cm Command Module Observatory telescope in Arizona and the 70 cm telescope at Thacher Observatory in California, and new high-resolution infrared spectra obtained with the Immersion Grating Infrared Spectrograph on the Discovery Channel Telescope. The masses and radii we measure for each component star disagree with previously reported measurements. We show that both stars are early M-type main-sequence stars without evidence for youth or hyper-inflation (

,

,

,

), and we update the orbital period and eclipse ephemerides for the system. We suggest that the likely cause of the initial hyper-inflated result is the use of moderate-resolution spectroscopy for precise radial velocity measurements.
Marat et Castel : l’expérience du prisme revisitée
Authors: Blay Michel
Published: July 2019

Dans cet article, sont présentés les enjeux post-newtoniens de l’étude des phénomènes de la couleur à partir de l’analyse des travaux critiques de Jean-Paul Marat et du Père Castel. Ces deux auteurs, en repartant de l’expérience newtonienne du prisme et en la réinterprétant à leur manière ne formulent en aucune façon des critiques au sens physique de l’expérience du prisme mais soulignent, dans une perspective épistémologique, la spécificité de cette expérience et la nature originale de ce qu’est un fait en science physique. Ces deux analyses critiques constituent donc un apport tout à fait important tant sur le plan de l’étude des couleurs que sur celui de la réflexion épistémologique. Après avoir rappelé les principaux aspects de la théorie newtonienne des phénomènes de la couleur, j’analyse avec soin la reprise de l’expérience du prisme par Marat et Castel, tout en attirant l’attention, d’une part, sur les problèmes liés à la perception visuelle de Marat et, d’autre part, sur les conséquences de la théorie newtonienne du point de vue de l’analyse de la sensation colorée au 18 e  siècle.
Palettes et tableaux : des laboratoires de la couleur ?
Authors: Guichard Charlotte
Published: July 2019

Intense objet de réflexion pour les peintres, la couleur fut redéfinie aux confins de la physique de la lumière, de la chimie des pigments et de la théorie de l’art tout au long du 18 e  siècle. Dans cet article, le tableau est envisagé à la manière d’une « trading zone » (P. Galison), un laboratoire où les différentes conceptions de couleurs furent mises à l’épreuve. En s’affranchissant notamment, avant le moment romantique, des théories du clair-obscur, certains peintres comme François Boucher utilisèrent une nouvelle palette et expérimentèrent un jeu nouveau sur la distribution des lumières et des ombres dans le tableau. À l’horizon de notre réflexion, émerge l’idée que les peintres des Lumières furent pleinement engagés dans les innovations optiques, chimiques et esthétiques qui transformèrent les usages de la couleur dans les arts visuels autour de 1800.
Le style « couleur de rose » de Marguerite de Lubert
Authors: Gladu Kim
Published: July 2019

Cet article se penche sur l’usage de la « couleur de rose » en littérature, à partir d’un texte exemplaire à cet égard : La Princesse Couleur-de-ros e et le Prince Céladon (1743) de Marguerite de Lubert. On verra que la couleur de rose y sert de métaphore du style rococo qui cherche à créer un effet sensible sur le lecteur, particulièrement à travers l’analyse de l’épisode où la princesse se trouve métamorphosée en livre et offerte à la lecture, au regard et aux caresses avides du prince Céladon. Le texte met alors à profit une écriture du plaisir pur, tel que défini dans le célèbre discours préliminaire servant de préface à Tecserion (1743), et qui n’est pas étrangère aux réflexions sur le coloris dans le domaine des beaux-arts.
Des pouvoirs de la couleur dans La Nouvelle Héloïse
Authors: Martin Christophe
Published: July 2019

À première vue, La Nouvelle Héloïse semble illustrer exemplairement une pauvreté chromatique assez générale dans le roman des Lumières qui, le plus souvent, ne semble nullement refléter l’importance nouvelle alors accordée aux couleurs. Lire La Nouvelle Héloïse au prisme de la couleur peut sembler d’autant plus paradoxal que le roman a toute chance d’avoir été composé à peu près au moment où Rousseau développe tout un discours anticoloriste dans l’ Essai sur l’origine des langues . Faut-il dès lors ne percevoir dans la Julie qu’une « condamnation puritaine de la couleur », selon la formule de Bernadette Fort ? En réalité, non seulement Rousseau ne reproche pas à la couleur de farder la réalité, mais il ne l’accuse pas non plus de séduire artificiellement les sens. À tenir compte des sujets d’estampe et à relire attentivement nombre de lettres du recueil, c’est au contraire toute une esthétique de la suggestion chromatique qui se laisse discerner dans le roman.
De la mémoire affective comme instrument compositionnel : Corinne de M me de Staël
Authors: Perrin Jean-François
Published: July 2019

Si Corinne est le premier grand roman de la mémoire affective après La Nouvelle Héloïse et avant Volupté , ce n’est pas pour telle ou telle scène brillante relative à la musique italienne ou à la poésie ossianique, mais parce que les réminiscences provoquées ou spontanées affectant les héros du roman structurent la composition de l’œuvre entière, tant en termes de progression dramatique, que de jeux maîtrisés, d’échos ou de contrepoint.
Adrien Lamourette et les philosophes : rupture ou continuité ?
Authors: Brucker Nicolas
Published: July 2019

Adrien Lamourette a-t-il varié dans son jugement sur les philosophes, leur rôle dans la Révolution et la crise religieuse ? Une approche historique, privilégiant une périodisation stricte et des facteurs circonstanciels, pencherait vers le oui, à la manière de la satire qui en 1792 oppose trois Lamourette. Les textes publiés avant et après les événements font apparaître d’évidents indices de continuité : Lamourette ne cesse de réfléchir sur un possible rapprochement entre les deux bords du monde intellectuel, sur une possible conciliation entre clercs et philosophes, et plus largement sur le lien entre religion et philosophie, faisant de la Révolution le pivot d’une pensée intégratrice, pensée qu’il n’a fait cependant qu’esquisser.
Evaluation of an Electronically Delivered Learning Module Intended for Continuing Education of Practicing Registered Nurses: A Pretest–Posttest Longitudinal Study
Authors: Schilinski Susan , Hellier Susan D. , Cline Thomas W.
Published: July 2019

Background:

A widely used method for distributing continuing education to health care professionals is via electronically delivered learning modules (EDLM). The purpose of this study is to determine if RNs retain and value education provided by an EDLM.

Method:

This is a one-group pretest–posttest and longitudinal study employing survey methodology. RNs completed an electronically delivered sepsis educational module, an immediate posttest, and then a posttest 4 weeks later. Additionally, the researchers measured participants' feelings and practices regarding EDLMs.

Results:

The mean value for total knowledge scores increased immediately postintervention then decreased to near baseline after 1 month. Additionally, participants reported that EDLMs did not increase their knowledge, nor did they value EDLMs.

Conclusion:

Our findings suggest that didactic information received via EDLMs may have minimal sustained impact on nurses' knowledge. Participants' lack of knowledge retention may be affected by module and evaluation design.

[
J Contin Educ Nurs.
2019;50(7):331–336.]
Biodegradable Waste a Nutrient Asset for Upholding Soil Health and Crop Production
Authors: Ashraf Ifra , Ramzan Shazia , Rashid Nowsheeba , Mir Ikhlaq A. , Jillani Asima
Published: July 2019

Management of solid wastes is a grave concern because of its associated significant negative impacts on quality of the environs. Accretion and putrefaction of solid wastes have potent hazardous effects on biotic and abiotic factors of the environment including human beings. Unmanaged solid wastes especially organic in nature add efficient quantity of greenhouse gases in the atmosphere. For dealing with wastes purely organic in nature, there is a need of an adequate waste management technology to reduce the quantity of organic waste being disposed of traditionally. Composting is an environmentally sound and sustainable approach to manage biodegradable fractions of solid waste. It has received considerable attention in the last few decades because of its potential of redressing the environmental pollution concerns associated with other waste disposal methods. This chapter is aimed to review supremacy of composting over other waste disposal methods.
Generation and Management of Biomedical Waste
Authors: Kalpana  , Azam Rifat , Parveen Nazia , Singh Dig Vijay , Azam Zaffar
Published: July 2019

Biomedical wastes (BMWs) are generated by the treatment of living organism as well as during research activities. With the increase of population in developing countries, generation of BMWs is increasing, but with inappropriate disposal management technologies. BMWs pose threats to the humans and also degrade the quality of environment. Handling of the BMWs by inexperienced and untrained staff increases the risk of accumulation of waste at the source as well as increases the chances of the spread of the dreadful diseases. The implementation of BMWs regulations is inadequate and unsatisfactory in developing countries: a major concern. Safe and reliable methods for management of BMWs are of utmost importance. The proper management of BMWs can be helpful in maintaining the overall quality of the environment. In order to get good results, the need is to increase the involvement of the ecofriendly techniques as well as increase awareness among the citizens, staff, and the workers directly involved in the management of the BMWs.
Innovations in Recycling for Sustainable Management of Solid Wastes
Authors: Parveen Nazia , Singh Dig Vijay , Azam Rifat
Published: July 2019

Rapid generation and accumulation of waste in developing countries is due to the increase in development, urbanization, industrialization, poor government policies, and population explosion. Various kinds of waste are produced in the developing countries but due to non-availability of ecofriendly environmental techniques, lack of resources, or the technical expertise, it is becoming difficult to treat the waste at the disposal sites. Most of the waste produced in developing countries is directly disposed to the landfills without any proper sorting and segregation, where it produces greenhouse gases, thus results in global warming. Recycling and composting is helpful in reducing the volume of the waste and producing valuable products which can have multiple applications. Thus, the requirement is to manage the waste by implementing strict laws, increasing awareness, utilization of innovative, as well as latest techniques (global system of mobile, geographical information system) in order to control the growing menace of the solid waste in developing countries.
High-Fidelity Multidisciplinary Design Optimization Methodology with Application to Rotor Blades
Authors: Wang Li , Diskin Boris , Biedron Robert T. , Nielsen Eric J. , Sonneville Valentin , Bauchau Olivier A.
Published: July 2019

A multidisciplinary design optimization procedure has been developed and applied to rotorcraft simulations involving tightly coupled, high-fidelity computational fluid dynamics and comprehensive analysis. A discretely consistent, adjoint-based sensitivity analysis available in the fluid
dynamics solver provides sensitivities arising from unsteady turbulent flows on unstructured, dynamic, overset meshes, whereas a complex-variable approach is used to compute structural sensitivities with respect to aerodynamic loads. The multidisciplinary sensitivity analysis is conducted
through integrating the sensitivity components from each discipline of the coupled system. Accuracy of the coupled system for high-fidelity rotorcraft analysis is verified; simulation results exhibit good agreement with established solutions. A constrained gradient-based design optimization
for a HART-II rotorcraft configuration is demonstrated. The computational cost for individual components of the multidisciplinary sensitivity analysis is assessed and improved.
To feel with and for Friedrich Schleiermacher: On religious experience
Authors: Veldsman Daniël P.
Published: July 2019

The German systematic theologian Friedrich Schleiermacher has shaped Western Christian theological thinking in many ways. One such influential way has been his formulation and exposition of religious experience, and specifically the concept of the ‘feeling of absolute dependence’ (Gefühl der schlechthinnigen Abhängigkeit). From a brief account of his understanding of the ‘feeling of absolute independence’, a few critical remarks are made from the broader context of contemporary hermeneutical discourses, focusing on the constitutive role of affectivity and narrative identity in religious experiences of embodied personhood. It is argued that these two themes in revisiting Schleiermacher’s understanding of the ‘feeling of absolute dependence’ can contribute to a more comprehensive understanding of religious experience.
The political economy of capital gains taxation in South Africa - Part II: The public choice of capital gains taxation and public policy
Authors: Spindler Zane A.
Published: July 2019

Public Finance and Public Choice principles are used to analyze the ideological and practical basis for the proposed introduction of a Capital Gains Tax into the income tax system of South Africa. The paper concludes that this is a flawed tax whose time has passed - especially for countries like South Africa.
Post-Soviet globalisation
Authors: Van der Hoek M. P.
Published: July 2019

In this paper, I will focus on the current situation with regard to globalisation from a historical perspective, while I will also look at possible future developments. The term globalisation appeared in a dictionary for the first time in 1961, but the concept of globalisation is not always clear. According to Levitt (1993) a global corporation "operates (...) as if the entire world (or major regions of it) were a single entity; it sells the same things in the same way everywhere". This describes a problem of some of US companies operating in foreign markets rather than to define globalisation meaningfully. Globalisation is sometimes viewed as synonymous to internationalisation, increasing international interdependence, or as a development towards relations acquiring relatively distanceless and borderless qualities. I interpret globalisation as economic integration of countries in the world economy on the basis of open markets and free movement of goods, services, workers and capital.
The role of mining in the South African economy
Authors: Fedderke Jobannes , Pirouz Farah
Published: July 2019

This paper examines the contribution of three aggregate mining sectors of the South African economy to output and employment over the 1970-97 period. The finding of a declining importance of mining in output and employment creation must be sectorally differentiated. Gold and Uranium Mining is the chief source of these declines, while evidence for Coal and Diamond and Other Mining is more modulated. We find strong redistribution of output from equity to labour over the course of the 1990s for Gold and Uranium Mining. In mining labour markets, we present developments in employment trends, in real labour cost, and in labour productivity. We examine links between these dimensions in an explanation of changing employment trends. We conclude with a VECM estimation of a labour requirements equation to corroborate our findings
The public finance management act as a reform measure to capacitate public officials
Authors: Fourie D. J.
Published: July 2019

The urgent need to develop South Africa's human resources in the public service has been conceptualized in many policy documents. The underlying objective of efforts to strengthen the human resources in the public sector, is the delivery of effective services to the people of South Africa. In line with the White Paper on the Transformation of the Public Service, 1995, the effective mobilization, development and utilization of human resources are stressed as important factors in the transformation of the public service because of their contribution to individual and institutional capacity to ensure effective governance. Financial resources are important in order to develop and sustain the skills of the public servants; however, there is a tendency to cut the budget for human resource development programmes. Alternative methods should be developed to obtain additional sources of income.
Aligned commitment and the high performance organisation
Authors: Kotze J. G.
Published: July 2019

In attempting to achieve high performance levels within the enterprise, the manifestation of aligned commitment is a very desirable goal to aim for. It is instrumental in the realisation of the full potential of organisational members and in focusing their efforts and performance on the strategic vision of the enterprise. A model, which introduces, describes, and integrates the various processes, steps and actions required in the development of aligned commitment, is suggested. Guidelines, derived from research findings as well as experience gained in the actual implementation of the various constituent elements of the model, are supplied. These guidelines should assist in the successful establishment and maintenance of a value-driven, aligned commitment culture within any enterprise.
Sales call anxiety: Investigating the role of fear in a selling situation
Authors: Rousseau G. G. , Jansingh L.
Published: July 2019

The main objective of this study was to investigate sales call anxiety (SCA)amongst insurance sales staff in Port Elizabeth. The study was based on past research and uses a modified questionnaire developed in previous research. The sample (N=112 sales persons) was drawn using a simple random sampling technique. Results confirm four dimensions of SCA identified by Verbeke and Bagozzi (2000), namely negative self-evaluation, negative evaluation from clients, physiological symptoms and protective actions. Significant differences in SCA between black and white salespeople were further observed. These findings have important implications for training of salespeople.
Sonar and LiDAR investigation of lineaments offshore between central New England and the New England seamounts, USA
Authors: Marple Ronald T. , Hurd, Jr. James D.
Published: July 2019

High-resolution multibeam echosounder (MBES) and light detection and ranging (LiDAR) data, combined with regional gravity and aeromagnetic anomaly maps of the western Gulf of Maine, reveal numerous lineaments between central New England and the New England seamounts. Most of these lineaments crosscut the NE-SWtrending accreted terranes, suggesting that they may be surface expressions of deep basement-rooted faults that have fractured upward through the overlying accreted terranes or may have formed by the upward push of magmas produced by the New England hotspot. The 1755 Cape Ann earthquake may have occurred on a fault associated with one of these lineaments. The MBES data also reveal a NW-SE-oriented scarp just offshore from Biddeford Pool, Maine (Biddeford Pool scarp), a 60-km-long, 20-km-wide Isles of Shoals lineament zone just offshore from southeastern New Hampshire, a 50-m-long zone of mostly low-lying, WNW-ESE-trending, submerged ridge-like features and scarps east of Boston, Massachusetts, and a ~180-km-long, WNW-ESE-trending Olympus lineament zone that traverses the continental margin south of Georges Bank. Three submarine canyons are sinistrally offset ~1–1.2 km along the Thresher canyon lineament of the Olympus lineament zone.
A Common Extension of Arhangel’skĭ’s Theorem and the Hajnal–Juhász Inequality
Authors: Bella Angelo , Spadaro Santi
Published: July 2019

We present a result about $G_{\unicode[STIX]{x1D6FF}}$ covers of a Hausdorff space that implies various known cardinal inequalities, including the following two fundamental results in the theory of cardinal invariants in topology: $|X|\leqslant 2^{L(X)\unicode[STIX]{x1D712}(X)}$ (Arhangel’skiĭ) and $|X|\leqslant 2^{c(X)\unicode[STIX]{x1D712}(X)}$ (Hajnal–Juhász). This solves a question that goes back to Bell, Ginsburg and Woods’s 1978 paper (M. Bell, J.N. Ginsburg and R.G. Woods, Cardinal inequalities for topological spaces involving the weak Lindelöf number, Pacific J. Math. 79(1978), 37–45) and is mentioned in Hodel’s survey on Arhangel’skiĭ’s Theorem (R. Hodel, Arhangel’skii’s solution to Alexandroff’s problem: A survey, Topology Appl. 153(2006), 2199–2217).

In contrast to previous attempts, we do not need any separation axiom beyond $T_{2}$.
Characterising the surface microlayer in the Mediterranean Sea: trace metals concentration and microbial plankton abundance
Authors: Tovar-Sánchez Antonio , Rodríguez-Romero Araceli , Engel Anja , Zäncker Birthe , Fu Franck , Marañón Emilio , Pérez-Lorenzo María , Bressac Matthieu , Wagener Thibaut , Desboeuf Karine , Triquet Sylvain , Siour Guillaume , Guieu Cécile
Published: July 2019

Abstract. The Sea Surface Microlayer (SML) is known to be enriched in trace metals relative to the underlaying water and to harbor diverse microbial communities (i.e. neuston). However, the processes linking metals and biota in the SML are not yet fully understood. In this study, we analyzed the metal (Cd, Co, Cu, Fe, Ni, Mo, V, Zn and Pb) concentrations in aerosol samples, SML (dissolved and total fractions) and in subsurface waters (SSW; dissolved fraction at ~ 1 m depth) from the Western Mediterranean Sea during a cruise in May–June 2017. The bacterial community composition and abundance in the SML and SSW, and the primary production and Chl-a in the SSW were measured simultaneously at all stations during the cruise. Residence times of particulate metals derived from aerosols deposition ranged from a couple of minutes for Co (2.7 ± 0.9 min; more affected by wind conditions) to a few hours for Cu (3.0 ± 1.9 h). Concentration of most dissolved metals in both, the SML and SSW, were well correlated with the salinity gradient and showed the characteristic eastward increase in surface waters of the Mediterranean Sea (MS). Contrarily, the total fraction of some reactive metals in the SML (i.e. Cu, Fe, Pb and Zn) showed negative trends with salinity, these trends of concentrations seem to be associate to microbial uptake. Our results suggest a toxic effect of Ni on neuston and microbiology community’s abundance of the top meter of the surface waters of the Western Mediterranean Sea.
Estimation of gas record alteration in very low accumulation ice cores
Authors: Fourteau Kévin , Martinerie Patricia , Faïn Xavier , Ekaykin Alexey A. , Chappellaz Jérôme , Lipenkov Vladimir
Published: July 2019

Abstract. We measured the methane mixing ratios of enclosed air in five ice core sections drilled on the East Antarctic plateau. Our work aims to study two effects that affect the recorded gas concentrations in ice cores: layered gas trapping artifacts and firn smoothing. Layered gas trapping artifacts are due to the heterogeneous nature of polar firn, where some strata might close early and trap abnormally old gases that appear as spurious values during measurements. The smoothing is due to the combined effects of diffusive mixing in the firn and the progressive closure of bubbles at the bottom of the firn. Consequently, the gases trapped in a given ice layer span a distribution of ages. Concentration measurements thus only measure the average value in the ice layer, which removes the fast variability from the record. We focus on the study of East Antarctic plateau ice cores, as these low accumulation ice cores are particularly affected by both layering and smoothing. Our results suggest that the presence of layering artifacts in deep ice cores is linked with the chemical content of the ice. We use high-resolution methane data to parametrize a simple model reproducing the layered gas trapping artifacts for different accumulation conditions typical of the East Antarctic plateau. We also use the high-resolution methane measurements to estimate the gas age distributions of the enclosed air in the five newly measured ice core sections. It appears that for accumulations below 2 cm ie yr−1(ice equivalent) the gas records experience nearly the same degree of smoothing. We therefore propose to use a single gas age distribution to represent the firn smoothing observed in the glacial ice cores of the East Antarctic plateau. Finally, we used the layered gas trapping model and the estimation of glacial firn smoothing to estimate their potential impacts on a million-and-a-half years old ice core from the East Antarctic plateau. Our results indicate that layering artifacts are no longer individually resolved in the case of very thinned ice near the bedrock. They nonetheless contribute to slight biases of the measured signal (less than 10 ppbv and 0.5 ppmv in the case of methane and carbon dioxide). However, these biases are small compared to the dampening experienced by the record due to firn smoothing.
Highly Efficient Artificial Photosynthesis of Formate from CO2 and Water on Heterojunction Copper Iron Oxide Catalysts
Authors: Park Hyunwoong , Kang Unseock , Suk Han Dong , Abdel-Wahab Ahmed
Published: July 2019

Solar CO2 recycling has received wide attention primarily to address global CO2 emission and to convert CO2 and water to value-added chemicals. Despite a long research history over the past four decades, the technology remains in an early stage, with low CO2 conversion efficiency and selectivity. CO2 is highly stable and has limited solubility in water, and its reduction requires multiple proton-coupled electron transfers, resulting in a range of carbon intermediates (C1–C3) as well as a larger amount of H2 over CO2 conversion products. For the realization of solar CO2 recycling, the system of interest should be operated sustainably, which requires the development of not only energy-efficient and cost-effective materials but also stand-alone, complete reaction processes (CO2 reduction and water oxidation) operating for long periods without any external bias. A range of semiconductors (mostly p-types) have been studied for CO2 conversion, including GaP, InP, GaAs, Si, Cu2O, and CuFeO2, all of which have narrow bandgaps (Eg) and sufficient Fermi levels (EF) capable of reducing CO2. Although promising, these aterials inherently require potential biases to drive the CO2 reduction reaction and compete with other metallic electrodes, whereas complete reactions (CO2 reduction and water oxidation) have been rarely demonstrated due to large overpotentials. Photocathode-photoanode couples have been demonstrated to operate, yet the syntheses of materials are complicated and the energy conversion efficiency is low. We have searched for high-efficiency, low-cost, and scalable p-type materials and found that CuFeO2 and CuO mixed materials meet all requirements. To our surprise, this material converted CO2 to formate with selectivity greater than 90% over 1 week and simultaneously produced molecular oxygen via water oxidation when simply wired to an inert anode (Pt foil) without any external bias under circum-neutral pH. The solar-to-formate (STF) energy efficiency was in the range of 0.7–1.2%, which is the highest reported value and comparable to the efficiency of photosynthesis occurring in most plants. For comparison, CuFeO2, CuO, and even Cu2O were fabricated; however, their efficiencies for formate production were much lower, and no oxygen was evolved.
Atmospheric Corrosion Behavior of Al 6xxx Alloys in Qatar State
Authors: Sliem Mostafa Hussien
Published: July 2019

Al 6000 series [Al-Mg-Si-Cu] are widely used in oil field for frames, tanks, pipelines and machinery applications. They showed a relatively high corrosion resistant, thermal and electrical conductivity and low cost. Establishing a materials map (Corrosion Atlas) for different region in Qatar. Al 6063 and Al 6082 are part of this map. Studying the forms of corrosion for the two Al alloys at different sites. Studying the corrosion rate, pit aspect ratio and pit density of the Al alloys after different times of exposure at different atmospheric condition. Many authors have been studied the corrosion behavior of aluminum alloys indoor significantly than the outdoor studies. However, the indoor corrosion studies seem to be markedly ignored numbers of air pollutants practically sulfur and chloride contaminations. In addition, weather exposure designs (outdoor tests) of aluminum and its alloys have been performed in different atmosphere all over the world by many countries. The aim of this article is to investigate the atmospheric corrosion behavior of Aluminum alloy Al-6063 after 6 months of exposure at seven different sites in Qatar which are representing different environments (Desert, industrial, coastal and marine) by visual observation with low power optical analysis for counting the pit depth and pit density for each site. In addition, electrochemical techniques were applied on the collected specimens to show the effect of the formed oxide layer on the corrosion behavior. SEM was used to study the susceptibility of studied alloys to intergrainular corrosion and the influence of sulfur and chloride compounds in intergrainular corrosion. The results were put in comparison with indoor test in 3.5% NaCl + 1%HCl mixture using SEM and Accelerated electrochemical techniques.
Effect of Surface Oxidation on Performance of Ti3C2Tx/MO Composite as Anode Materials for Lithium Ion Batteries
Authors: Ali Adnan
Published: July 2019

Recently, a new group of 2D material showed a great promise in supercapacitors and batteries application due to their good conductivity as well as hydrophilic nature [1]. It has general formula Mn+1Xn, where n = 1, 2 or 3, M is an early transitional metal and X is C and/or N [2]. According to X-ray photoelectron spectroscopy (XPS) and energy dispersive x-ray spectrometry (EDS) studies, MXenes can be terminated with a mixture of O, OH, and/or F groups depending on the chemical etching method and post-treatment. The as-synthesized MXenes are electronically conducting and hydrophilic, which is a unique combination. Ultrasonication can be used to delaminate the 2D layers and produce single-layer and few-layered flake [3].

As MXenes are hydrophilic, once delaminated, they form stable, surfactant-free colloidal solutions in water. The possibility of intercalating MXenes with various organic molecules plays a critical role for utilizing MXene in a range of applications, from polymer reinforcements to energy storage systems. The MXenes’ 2D morphology, together with to their good electronic conductivities, render them strong candidates for many applications that range from sensors and electronic device materials to catalysts in the chemical industry, conductive reinforcement additives to polymers, and electrochemical energy storage materials, among many others [4].

We have used hydrothermal route to synthesize nanocomposite material i.e. Ti3C2Tx/MO (MO = Fe2O3, Co3O4). After hydrothermal treatment, nanocomposite was calcinated at 400°C for 4 hours to get rid of entrapped moisture. Nano-composite was characterized using scanning electron microscopy, transmission electron microscopy and X-ray diffraction. After synthesis, nanocomposite was applied as anode in lithium ion battery. Anode was fabricated as thin film using doctor blade on copper foil.

Ti3C2Tx/Fe2O3 composite as anode material exhibited discharge and charge capacities of 190 and 120 mAh/g, respectively. Characterization shows that the MO nanoparticles are not uniformly distributed and also X-ray diffraction analysis has confirmed that Ti3C2Tx has oxidized during hydrothermal treatment. Due to oxidation, the surface of Ti3C2Tx was decomposed to TiO2 and leaving carbon sheets behind which played a big role in decreasing conductivity of the anode. In turn, it has greatly affected its performance as anode material in the lithium ion batteries. To enhance its performance as anode material in Lithium ion batteries, it is extremely important to protect it from oxidizing. For this purpose, it should be exfoliated in a medium other than water. Besides this, metal oxide should be uniformly distributed.
Isolation and Identification of Potentially Pathogenic Vibrio Species from Qatari Coastal Seawaters
Authors: Anand Anjana , Zeyara Aisha , Al Malaki Amina , Al-Ghanim May M. , Hitha P.K. , Al deen Saad Taj , Al Marri Masoud , Fotedar Rashmi
Published: July 2019

The genus Vibrio accounts for a major group of marine and estuarine bacteria capable of causing diseases in various aquatic organisms including fishes, corals, shellfish's and shrimps. Infections with these organisms have profound environmental and economic consequences. In the present study, 52 isolates of Vibrio species were isolated from the water samples collected from 14 sites surrounding Qatar during the winter season. Using 16S rRNA gene sequence analysis and MALDI-TOF MS we identified 13 different luminous and non-luminous Vibrio species. V. alginolyticus (50%) was the predominant species followed by V. harveyi (11%), V. owensii (7%), V. nigripulchritudo (6%), V. rotiferianus (6%), V. mediterranei (6%), V. hepatarius (2%), V. shilonii (2%), V. maritimus (2%), V. coralliilyticus (2%), V. tubiashii (2%), V. parahaemolyticus (2%), and V. proteolyticus (2%). We were able to identify all (100%) isolates using 16S rRNA, (>94 percentage similarity) as compared to MALDI TOF-MS which could correctly identify only 60% isolates. Majority (70%) of the potentially pathogenic Vibrio's isolates of Vibrio's were recovered from the fishing ports of Qatar namely Al-Khor and Al-Wakra. The isolation of various pathogenic species of Vibrio's from the Qatari marine environment indicates the potential sanitary risk and stresses the need for further studies to prevent infections.

Acknowledgments:

This research was supported by the research grant (Grant NPRP 6-647-1-127) from the Qatar National Research Fund (a member of Qatar Foundation) to R. Fotedar (Ministry of Environment, Qatar), Thorsten Stoeck (L, Germany), Teun Boekhout (CBS- KNAW, The Netherlands) and Jack Fell (RSMAS,USA).
The Role of 4-hydroxynonenal in Human Preadipocyte Proliferation and Differentiation
Authors: Elrayess Mohamed A. , Al Muraikhi Shamma , Al-Khelaifi Fatima , Al-Yafei Afnan , Bashah Moataz , Jaganjac Morana
Published: July 2019

Accumulation of lipid peroxidation products in response to oxidative stress can cause dysfunction and pathology in a variety of tissues. In this study, we investigated the presence of 4-hydroxynonenal (4-HNE), the most abundant lipid peroxidation end product, in paired subcutaneous (SC) and omental (OM) tissues obtained from morbidly obese individuals undergoing weight reduction surgery. We further assessed 4-HNE effect on proliferation and differentiation of preadipocytes derived from these tissues in two metabolically distinct groups. Levels of 4-HNE accumulation were positively correlated between the paired SC and OM tissues (R2 = 0.9, p = 0.01) and exhibited a higher accumulation in OM-adipocytes and connective tissues compared to SC-derived counterparts. Exposure of tissues-derived preadipocytes to physiological levels of 4-HNE caused inhibition of proliferation and differentiation of SC, but not OM-derived preadipocytes. When samples were dichotomized into insulin sensitive (IS) and insulin resistant (IR) groups based on their HOMA-IR index, 4-HNE treatment caused a greater reduction of both proliferation by 76% with a mean difference of 11.4% (3–45.3) and differentiation capacity by 56% with a mean difference of 25.9% (3.9–55.7) in IS compared to IR. This data suggest that 4-HNE induced oxidative stress plays a role in the regulation of adipocyte proliferation and differentiation in a depot and insulin sensitivity-specific manners and may therefore contribute to metabolic dysfunction associated with insulin resistance. This research was sponsored by Qatar National Research Fund (QNRF), Grant number NPRP6-235-1-048.
Exploring the SIRT1/P53 Pathway in Adipocytes Hyperplasia
Authors: Abdesselem Houari
Published: July 2019

The expansion of fat mass in the obese state is due to increased adipocyte hypertrophy and hyperplasia. Knowledge on what drives adipocyte hyperplasia in obesity remains limited. SIRT1, a key regulator of mammalian metabolism, maintains proper metabolic functions in many tissues counteracting obesity. By stably knocking down SIRT1 in mouse 3T3-L1 preadipocytes, we demonstrate that SIRT1 is a key regulator of proliferation in preadipocytes and mitotic clonal expansion (MCE) in differentiating adipocytes. Quantitative proteomics reveals that the p53 pathways is altered to drive enhanced proliferation in SIRT1 knockdown preadipocytes. Moreover, p53 is hyperacetylated, p27 is reduced and CDK2 is activated in SIRT1-silenced preadipocytes. Remarkably, differentiating SIRT1-silenced preadipocytes exhibit enhanced MCE accompanied with reduced p27, increased C/EBPβ, and also have hyperacetylated p53, leading to hyperplastic and dysfunctional adipocytes. Better understanding of the molecular mechanisms of adipocyte hyperplasia will open new venues towards understanding obesity.
Filamin A is Reduced and Contributes to CASR Sensitivity in Human Parathyroid Tumors
Authors: Terranegra Annalisa , Mingione Alessandra , Verdelli Chiara , Brasacchio Caterina , Pivari Francesca , Dogliotti Elena , Corbetta Sabrina , Soldati Laura
Published: July 2019

Background

Parathyroid tumors display reduced sensitivity to extracellular calcium ([Ca2+]o). The parathyroid cell sensitivity to [Ca2+]o is mediated by the calcium-sensing receptor (CASR), a G-protein-coupled receptor interacting with the scaffold protein filamin A (FLNA). We investigated: the FLNA expression in human parathyroid tumors, its effect on the CASR membrane stabilization, and on ERK signaling activation in HEK293 cells, the effect of the C-terminal CASR variants (R990G) on the interaction with FLNA.

Methods

FLNA expression was analyzed by immunohistochemistry and immunofluorescence in parathyroid tumors and in cells from parathyroid adenomas (PAds). Endogenous FLNA in HEK293 cells transfected with the CASR variants was silenced by siRNA technique. Results FLNA expression was down-regulated in human parathyroid tumors; In 74 PAds, FLNA mRNA levels positively correlated with CASR levels. In HEK293 cells transfected with 990R-CASR or 990G-CASR, FLNA silencing reduced both the total and membrane protein expression levels. However, in presence of endogenous FLNA, 990G-CASR expression in cell membrane was higher than that of the 990R-CASR. FLNA loss reduced significantly p-ERK levels induced both 990R-CaSR and 990G-CaSR. Treatment with the CASR agonist R568 delete the effect of FLNA loss and restoring 990G-CASR sensitivity to [Ca2+]o in absence of FLNA.

Conclusions

FLNA is down-regulated in parathyroid tumors and paralleled the CASR expression levels. Loss of FLNA reduced the CASR expression levels and the CASR-induced ERK phosphorylation. The CASR 990G allele was associated with increased sensitivity to [Ca2+]o, though FLNA was required to determine the 990G-CASR higher expression and activity than that of 990R-CASR protein.
Application of Pulsed Streaming Potentials in Plastic Microfluidic Channels for Quantitative Point-of-Care Determination of Cardiac Markers
Authors: Elazazy Marwa , Alvarez Julio
Published: July 2019

Acute myocardial infarction (AMI) is a well-recognized angiocardiopathy that can be spotted by a rise and fall of “chemical biomarkers” in a clinical context. Biomarkers are then, valuable indicators, together with ischemic symptoms, of an impaired cardiac function. Assay of Cardiac troponin T (cTnT), the biomarker of choice, is now an indispensable element in the medical practice followed to diagnose and control AMI. Though being proved sensitive and cardiospecific, the enhancement of diagnostic sensitivity attained using CTnT, have noticeably come with a reduction in specificity. Herein, we report a new sensing strategy based on pulsed streaming potential for direct determination of CTnT. The current biosensor consists of a patterned microchannel built with commodity thermoplastic cyclo olefin copolymer (COC). Specific binding of “avidin to biotin” on an “EDC-NHS” modified microchannel was used to tether biotinylated “anti-troponin T monoclonal Ab” to our target “CTnT”. Furthermore, the selectivity of the created platform was tested with success in serum samples. The analytical response to this system was measured by changes in magnitude of the streaming potential and correlated with the amount of analyte bound to the sensor surface. Different from the well-established biochemical assays adopted for cTnT, the current biosensor does not require labeling (fluorescent, electrochemical or radioactive) or usage of tedious chemical procedures. In addition, a stable quick response is attained under pulsed flow not steady state conditions, which permits a real time analysis. The linear region (1.9–6.5 μg/mL) matches with the clinically relevant concentrations of cTnT in human serum which has a cutoff value of 4 ng/mL.
Physical Exercise Alleviated ER Stress in Obese Humans through Reduction in the Expression and Release of GRP78 Chaperone
Authors: Khadir Abdelkrim , Tiss Ali , Abubaker Jehad , Abu-Farha Mohamed , Dehbi Mohammed
Published: July 2019

Several lines of evidence implicated the pathophysiological role of the endoplasmic reticulum (ER) stress in obesity-induced insulin resistance and diabetes. Using a targeted transcriptomic profiling approach consisting of the Heat Shock Response RT2 Profiler PCR Array, we previously reported impaired expression of DNAJB3/Hsp-40 cochaperone in obese and diabetic human subjects that was restored by physical exercise. In addition to DNAJB3/Hsp-40, three other genes showing differential expression between lean and obese human subjects were identified and GRP78 is the subject of our current investigation. Using histochemistry, immunofluorescence and western blots, our data show that GRP78 protein is increased in the adipose tissue obese subjects and thus, confirming the initial transcriptomic approach. More interestingly, higher levels of circulating GRP78 protein were found in obese compared to lean subjects and they correlated negatively with VO2, Max but positively with CRP and the obesity indicators such as BMI, body fat, and waist circumference. As GRP78 is the master regulator of the Unfolded Protein Response (UPR), we investigated the status of three arms of the UPR namely ATF6, IRE1a and PERK. Consistent with the finding on GRP78, our data indicated a marked increase in the expression and activity of these three arms in the adipose tissue from obese subjects. We finally tested the hypothesis that physical exercise could modulate the expression and release of GRP78 and its downstream targets. Here, we provide for the first evidence that physical attenuated significantly the endogenous expression and release of GRP78 with a concomitant reduction in the activity of IRE1a and eIF2a. Taken together, these results strongly suggest that exercise alleviated ER stress in obese subjects through attenuation of GRP78 signaling network.
Histone Deacetylase Inhibitor Trichostatin A (TSA) and DNA Methyltransferase Inhibitor 5-aza-2′-deoxycitidine (5-AZA) Enhanced the Cisplatin (CDDP) Induced Cytotoxicity of Neuroblastoma Cells, in Vitro
Authors: Busselberg Dietrich , Varghese Elizabeth , Florea Ana-Maria
Published: July 2019

Neuroblastoma is a childhood cancer that is frequently treated with CDDP. Upon chemotherapeutic treatment, neuroblastoma patients might develop drug resistance. A large body of evidence associates the cytotoxic effect of CDDP in cancer cells with the formation of DNA adducts and thus interference with the DNA replication of cancer cells but also with the increase of the intracellular calcium concentration ([Ca2+]i) that leads to apoptosis. Nevertheless, it is not understood how epigenetic mechanisms, such as DNA methylation and chromatin modification might influence the effect of CDDP on cytotoxicity and [Ca2+]i of neuroblastoma cells.

Therefore, here we investigate in human neuroblastoma cell lines SH-SY5Y and IMR-32 the changes in cytotoxicity and calcium homeostasis induced by the treatment with epigenetic modulators: TSA and 5-AZA but also in combination with CDDP.

Treatment schemes for calcium homeostasis experiments were performed in four different groups: A) treatment with CDDP only (control); B) acute treatment with 5-AZA or TSA (without CDDP); C) pre-treatment with both 5-AZA and TSA (before CDDP application), D) pre-treatment with 5-AZA (before CDDP). For cytotoxicity test: the Trypan Blue Cytotoxicity test was performed using the automated cell counter ViCellXR (Beckman Coulter, Germany), for exposure times ranging 24–72 h. The concentrations used were for 5-AZA ranging 1–200 μM while for TSA 1–10 μM were used.

The results showed significant increase of neurblastoma cells cytotoxicity upon treatment, especially for the combinatory treatment 5-AZA and TSA. We observed a time and concentration dependent increased cytotoxicity. The most efficient treatment was the combination 5-AZA and TSA, showing additive effects. TSA showed higher efficiencity triggering cytotoxic effects in neuroblastoma cells than 5AZA. Furthermore, the combinatory treatment of neuroblastoma cells with epigenetic modulators and CDDP increased the efficiency of CDDP treatment in a synergistic manner, effect that could be confirmed in IMR32 cells. Thus, the combination 5-AZA/CDDP or TSA/CDDP or 5-AZA /TSA/CDDP was more effective in triggering cell death of neuroblastoma cells than each of the compound alone.

For the investigation of changes in [Ca2+]i we performed calcium imaging studies using the calcium sensitive dye Fluo-4-AM in Tyrode's buffer with calcium (1.5 mM). Fluorescent images were taken with Olympus Microscope BX51 Wi with Xenon Arc Burner and “Xcellence rt” software. CDDP (1 μM) treatment (control group) increased the [Ca2+]i (30.3% ± 11.7) group “A” in SH-SY5Y cells. This effect of CDDP was reversed by the pretreatment with 5-AZA and TSA group “C” (5.1% ± 5.1) (p