bluuebunny/crossref_metadata_2025 huggingface dataset:
Quand les tout-petits apprennent… entre liaison et déliaison
Authors: Blain-Joguet Evelyne
Published: March 2018

Comment fait-on travailler les tout-petits à la Maternelle. Le challenge est important, car c’est dans ces premières années que peut se construire tout le rapport futur de l’enfant avec l’école. Évelyne Blain Joguet nous explique comment elle part du connu, du désir d’apprendre des enfants, pour les emmener vers l’inconnu, vers ce qui peut inquiéter, déranger. Chemin faisant, elle leur apprend à se développer, à grandir, à faire confiance, à s’autonomiser. Et tout cela avec beaucoup de respect, de bienveillance et de créativité. J’aurais rêvé d’avoir une “maîtresse” comme cela ! Cet article nous donne envie de revenir à nos jeunes années et de retourner à l’école. FB
E-learning content design standards based on interactive digital concepts maps in light of meaningful learning theory and constructivist learning theory
Authors: Afify Mohammed
Published: March 2018

The present study aims to identify standards of interactive digital concepts maps design and their measurement indicators as a tool to develop, oraganize and administer e-learning content in the light of Meaningful Learning Theory and Constructivist Learning Theory. To achieve the objective of the research, the author prepared a list of E-learning content design standards based on interactive digital concepts maps. It involved (11) general standards and (40) performance indicators. It was investigated by 21 teaching staff members who are experts in educational technology and e-learning to ration the list and its performance indicators. Results illustrated that standards are too significant and appropriate for the purpose of the study. Results were discussed in the light of theoretical background results of researches and literature review in the field. The study provided recomendations and suggestions that can be used as practical applications in the field of developing E-learning content based on utilizing interactive digital concepts maps.
Do Projects really end late? On the shortcomings of the classical scheduling techniques
Authors: Ballesteros-Pérez Pablo , Larsen Graeme D. , González-Cruz Maria C.
Published: March 2018

Many engineering projects fail to meet their planned completion dates in real practice. This a recurrent topic in the project management literature, with poor planning and controlling practices frequently cited among the most significant causes of delays. Unfortunately, hardly any attention has been paid to the fact that the classical scheduling techniques: Gantt chart, Critical Path Method (CPM), and Program Evaluation and Review Technique (PERT), may not be as fit for purpose as they seem. Arguably, because of their relative simplicity, these techniques are still almost the only ones taught nowadays in most introductory courses to scheduling in many engineering and management degrees. However, by utterly ignoring or inappropriately dealing with activity duration variability, these techniques provide optimistic completion dates, while suffering from other shortcomings. Through a series of simple case studies that can be developed with a few participants and common dice, a systematic critique of the classical scheduling techniques is offered. Discussion of the case studies results illustrate why limiting the contents of scheduling education and teaching can be detrimental, as the aforementioned classical scheduling techniques cannot not provide project managers with sufficient resources to effectively plan and control real projects.
Evolution of project-based learning in small groups in environmental engineering courses
Authors: Requies Jesús M. , Agirre Ion , Barrio V. Laura , Graells Moisès
Published: March 2018

This work presents the assessment of the development and evolution of an active methodology (Project-Based Learning –PBL-) implemented on the course “Unit Operations in Environmental Engineering”, within the bachelor’s degree in Environmental Engineering, with the purpose of decreasing the dropout rate in this course. After the initial design and implementation of this methodology during the first academic year (12/13), different modifications were adopted in the following ones (13-14, 14-15 & 15-16) in order to optimize the student’s and professor’s work load as well as correct some malfunctions observed in the initial design of the PBL. This active methodology seeks to make students the main architects of their own learning processes. Accordingly, they have to identify their learning needs, which is a highly motivating approach both for their curricular development and for attaining the required learning outcomes in this field of knowledge. The results obtained show that working in small teams (cooperative work) enhances each group member’s self–learning capabilities. Moreover, academic marks improve when compared to traditional learning methodologies. Nevertheless, the implementation of more active methodologies, such as project-based learning, in small groups has certain specific characteristics. In this case it has been implemented simultaneously in two different groups of 10 students each one. Such small groups are more heterogeneoussince the presence of two highly motivated students or not can vary or affect the whole group’s attitude and academic results.
The impact of virtual trips on the development of Arabic language listening skills among third grade students in Jordan
Authors: Alhajya Nail M. , Alzaghamim Sumaia S. , Arouri Yousef M.
Published: March 2018

This study aimed at investigating the impact of virtual trips on developing Arabic language listening skills among third grade students in Jordan. The researchers used a quasi-experimental design to answer the research questions. The study sample consisted of 48 students who were chosen purposely. Those participants were divided randomly into two groups: 1) experimental group which consisted of 24 students who were taught by using a Virtual Trip Model (VTM), and 2) control group which consisted of 24 students who were taught by using a traditional method of teaching. To achieve the study objectives, the researchers developed a content-based VTM and achievement test to measure Arabic language listening skills. Reliability and validity of the study instruments were checked. To answer the study questions, means and standard deviations were calculated, and ANCOVA test was used. Study results revealed that there were statistically significant differences (α=0.05) between means of students’ achievement test scores attributed to teaching method variable, and in favor of the experimental group.  Furthermore, there were no statistically significant differences (α=0.05) between means of students’ achievements test scores attributed to gender variable, and the interaction between teaching method and gender variables. Additional implications and future recommendations were argued.
JOTSE'S internationalisation: Goal achieved
Authors: Amante Beatriz , Martínez Martínez María
Published: March 2018

.
Revisiting the upper floors of the Casa d'Argo at Herculaneum*
Authors: Andrews James N.
Published: March 2018

La Casa d’Argo a été la première maison fouillée à ciel ouvert au début du xixe siècle ; elle possédait au moment de sa découverte des étages encore bien conservés, avec des réserves contenant de nombreux restes de nourriture et des salles de réception luxueuses. Ils furent malheureusement détruits peu après avoir été fouillés et les détails fournis par le responsable des fouilles, Carlo Bonucci, sont restés largement ignorés. Or il est rare d’avoir conservé, sur des sites romains, des étages : la Casa d’Argo constitue donc un cas d’étude unique qui peut nous aider à reconsidérer notre connaissance de l’espace domestique romain. L’article propose de reconstituer les étages de la maison en se fondant sur les éléments architecturaux et décoratifs documentés, ainsi que les trouvailles effectuées. L’analyse montre que les étages ont joué des rôles différents : l’un servait d’espace de stockage et de service, tandis que l’autre a servi à des activités de réception qui ont pu revêtir un caractère public. La question de l’accès et de la visibilité de ces étages est également importante ; il semblerait que l’usage des espaces ait été saisonnier et plus complexe que ce que l’on pensait jusque-là.
BLUETOOTH-BASED WIRELESS DIGITAL STETHOSCOPE WITH MOBILE INTEGRATION
Authors: Degbedzui Derek Kweku , Tetteh Michael , Kaufmann Elsie Effah , Mills Godfrey A.
Published: March 2018

Acoustic stethoscopes are used to monitor signals from patients. Incidentally, the connecting tube between the chest-piece and the ear-piece of common stethoscopes is known to serve as a medium for transmitting pathogens from patients to physicians or from one patient to another patient. This work presents a wireless stethoscope design with mobile integration that transmits heart sounds to mobile devices for evaluation and analysis, thus, eliminates the connecting tube. This is an extension of the previous work that presented the proof of concept of a wireless stethoscope with Bluetooth transmission. In this work, however, the chest-piece of the traditional stethoscope is integrated with microcontroller unit and Bluetooth communication device. Captured signals are processed and transmitted wirelessly to a mobile device with interface application software for recording, listening and visual display of waveforms. Following numerical simulation, a prototype was developed. Testing conducted on the prototype device using a class 2 Bluetooth device with 4[Formula: see text]dBm transmission power showed good quality received signals when the mobile device was placed 20[Formula: see text]m within indoor environments and 42[Formula: see text]m in open-space outdoor environment, beyond which degradation in quality occurs. It is worth pointing out that a smart Bluetooth device with high transmission range and data speed may produce much longer operating distance. Hence, for applications that require operating ranges beyond 50[Formula: see text]m, smart Bluetooth devices may be well suited for such systems. This system may serve as the means for monitoring patients from remote locations particularly quarantine units and can also be useful for training health personnel through broadcasting of recorded signals for analysis and evaluation by members of a medical team.
IMPROVEMENT OF THE PERFORMANCE OF FINGERPRINT VERIFICATION USING A COMBINATORIAL APPROACH
Authors: Alimardani Fatemeh , Boostani Reza
Published: March 2018

Fingerprint verification systems have attracted much attention in secure organizations; however, conventional methods still suffer from unconvincing recognition rate for noisy fingerprint images. To design a robust verification system, in this paper, wavelet and contourlet transforms (CTS) were suggested as efficient feature extraction techniques to elicit a coverall set of descriptive features to characterize fingerprint images. Contourlet coefficients capture the smooth contours of fingerprints while wavelet coefficients reveal its rough details. Due to the high dimensionality of the elicited features, across group variance (AGV), greedy overall relevancy (GOR) and Davis–Bouldin fast feature reduction (DB-FFR) methods were adopted to remove the redundant features. These features were applied to three different classifiers including Boosting Direct Linear Discriminant Analysis (BDLDA), Support Vector Machine (SVM) and Modified Nearest Neighbor (MNN). The proposed method along with state-of-the-art methods were evaluated, over the FVC2004 dataset, in terms of genuine acceptance rate (GAR), false acceptance rate (FAR) and equal error rate (EER). The features selected by AGV were the most significant ones and provided 95.12% GAR. Applying the selected features, by the GOR method, to the modified nearest neighbor, resulted in average EER of [Formula: see text]%, which outperformed the compared methods. The comparative results imply the statistical superiority ([Formula: see text]) of the proposed approach compared to the counterparts.
Optical and Morphology Changes upon Self-Assembly of Tetrasulphonated Copper Phthalocyanine and Polyaniline Particles on Zinc Oxide Nanorods
Authors: Marquez Menandro C.
Published: March 2018

Zinc oxide (ZnO) nanorods were grown on the pre-seeded substrate using a facile, solution route technique. The multilayer self-assembly of polyaniline (PAni) and tetrasulphonated phthalocyanine (TSCuPc) on ZnO nanorods was monitored by FTIR, UV-Vis SEM and XRD. Infrared spectrum of the assembled layer showed peaks centered at 1589cm-1and 1504 cm-1, confirmed the presence of quinoid and benzenoid structures of PAni, while peaks centered at ~1165cm-1and ~775cm-1 provided evidence for the presence of TSCuPc species. Absorption spectra of the assembled layer show broadened peaks at ~600nm and ~700nm affirmed the presence of PAni and TSCuPc molecules. A linear increase in the absorbance level at these wavelengths was also observed upon increasing the number of bilayers. The surface modification of the ZnO nanorods after self-assembly was confirmed through SEM. The edges of the ZnO nanorods was observed to change from sharp to dull upon employing layer by layer deposition of PAni and TSCuPc. XRD pattern of the assembled layer showed broadened peaks at low 2Θvalues associated to the amorphous nature of the emeraldine base of PAni. Even so, the diffraction peaks in XRD patterns of ZnO nanorods and ZnO/(TSCuPc-PAni) multilayer have been indexed as hexagonally wurtzite structure. The multilayer deposition of PAni and TSCuPc on the surface of ZnO as monitored by UV-Vis spectroscopy and confirmed by FTIR, XRD, and SEM provides a new way of anchoring dye molecules without carboxylic moieties on the surface of metal oxides
Production of Biomass Fiber Packaging Material by Microwave Foaming Method
Authors: Sun Hao , CAO Yangfen , Wei Ling Jun , Qian Jing , Wang Li Qiang , Zhang Xin Chang
Published: March 2018

In recent years, the production and application of plastic planting tray is subject to more restrictions, many scholars at domestic and abroad are actively to develop biodegradable biomass packaging materials. Based on these analysis and summarization, make use of treated sludge, waste paper fibers and industrial waste wood chips as raw materials, adding other environmental protection additives to prepare a kind of biomass foaming material which has low quality, low density and good mechanical properties. Text result shows that it is feasible to use this method to make environmental material, and its density is 0.43g/cm3, the compressive strength is 10.64MPa.
Synthesis and Characterization of Cu/ZnO Catalyst on Carbon Nanotubes and Al2O3 Supports
Authors: Zabidi Noor Asmawati Mohd , Tuan Sulong Tuan Syahylah , Ali Sardar
Published: March 2018

CO2 conversion into valuable chemicals is an attractive option to deal with the increasing CO2 concentration in the atmosphere. In this study, Cu/ZnO catalyst was synthesized on multi-walled carbon nanotubes (MWCNTs) and Al2O3 supports via incipient wetness impregnation method. The physicochemical properties of the catalysts were investigated using TEM, XRD, N2 adsorption-desorption analysis, H2-TPR and XPS. The performance of the synthesized catalysts in a CO2 hydrogenation reaction was evaluated in a fixed-bed reactor at 503 K, 22.5 bar and H2:CO2 ratio of 3:1. TEM images showed that Cu/ZnO nanoparticles were deposited inside the CNTs as well as on the exterior walls of the CNTs. The average CuO crystallite size on Al2O3 and CNTs supports was 15.7 and 11 nm, repectively. Results of H2-TPR studies showed that the reducibility of the catalyst was improved on the CNTs support. XPS analysis confirmed the presence of Cu2+ in the samples, however, the binding energy of Cu 2p3/2 peak on the Al2O3 support was shifted to higher value compared to that of CNTs support. Products obtained from the CO2 hydrogenation reaction in the presence of these catalyts were methanol, ethanol, methyl formate and methane. The CO2 conversion of around 23% was obtained using both types of catalysts, however, Cu/ZnO on CNTs resulted in higher yield of methyl formate compared to that of Al2O3-supported catalyst.
Mass-Producible Organic Nanocapsule with Water-Responsive Releasing Ability
Authors: Kogiso Masaki , Ding Wu Xiao , Masuda Mitsutoshi
Published: March 2018

An organic nanocapsule was obtained by mixing zinc acetate powder into a peptide lipid dispersion in ethanol. The nanocapsule was mass-produced at a scale of over 100 g L–1 within 1 h. Fourier transform infrared spectroscopy and scanning electron microscopy revealed that a zinc-peptide lipid complex was formed within 15 min, which subsequently transformed into a nanocapsule as a result of changes in the hydrogen bonding networks between the peptides. A variety of organic dyes could be encapsulated by simply adding them during the nanocapsule formation. We also confirmed their high stabilities in organic solvents, water-responsive morphological change, and resulting guest release. The water-responsive nanocapsule is expected to be useful in a variety of fields.
Neural Network as an Assisting Tool in Designing Talus Implant
Authors: Daud Rosdi , Suaidah Sulaiman , Mas-Ayu H. , Tomadi Siti Haryani , Salwani Mohd Salleh , Shah Arman , Abdul-Kadir Mohammed Rafiq
Published: March 2018

The design of current talus implant are focusing too much on mechanical simplicity and usually based on certain population which tends to ignore the anatomically difference between populations. An anatomically talus implant design is known can reduce the contact pressure but one of the constraints for designing implant anatomically is to get bone parameters. This is due to the difficulty to get enough volunteers in getting bone parameters using hazardous method (X-ray or CT scan) .Thus, the talus implant (TI) for particular population was developed based on artificial neural network (ANN) prediction. By using Finite Element Method (FEM), numerical models that include mainly the talus bone and the talus implants are created to compare the contact pressure distribution of the newly develop talus implant with the three different kind of current talus implant designs (BOX, STAR & TNK). For FEM results, only BOX and the newly develop talus implant exceeded the contact stress recommended for the superior articular surface compared to the others. The results also showed that the stress increased near the resected surface. Thus, it is agreed that excessive bone resection may not support the force at the ankle which consequently may contribute to early loosening and subsidence of the talus implant. It is concluded that the excessive bone resection can be avoided by perfectly match talus implant which only can be achieved by designing talus implant for a particular population.
Development of Mesoporous Magnetic Hydroxyapatite Nanocrystals
Authors: Wu Hsi Chin , Lin J.Y. , Wang Tzu Wei
Published: March 2018

Mesoporous magnetic hydroxyapatite nanocrystals (MPmHAp NCs) were successfully prepared through one-step co-precipitate process. From the results, the MPmHAp NCs kept HAp lattice structure and had short rod-like morphology with superparamagnetic property. The size of MPmHAp was 60-80 nm in length and 10-20 nm in width. It also had excellent cell viability when coculture with 3T3 cells in vitro. In addition, MPmHAp NCs not only possessed mesoporous architecture with high surface area for effective drug loading capacity and drug release. The above results indicate that the biocompatible MPmHAp NCs showed great potential as multifunctional therapeutic nanoagent for biomedical application.
The Influence of Sulfates on Tobermorite Formation in Lime-Ash Composite
Authors: Černý Vit , Melichar Jindřich , Fleischhacker Jan , Drochytka Rostislav
Published: March 2018

Autoclaved aerated concrete is an ecological building material with suitable properties and long-time tradition. The research of secondary raw materials usage and technology optimization is needed in order to increase the efficiency and sustainability of its production. It is important to focus on development of mineralogical composition while studying the influence of input materials and the parameters of hydrothermal synthesis on the properties of final product. This is especially important in case of tobermorite formation as the bearer of strength in the structure. Main focus of this paper is applicability of fly ash (silica component) and admixture of energo-gypsum (sulfate component) in production of lime-ash composite in hydrothermal conditions. The research was focused on autoclaving of samples at temperature of 170°C in three various isothermal sustains. Final samples were analyzed by XRD and SEM in order to proof the influence of input materials. Results show that 5% admixture of energo-gypsum had positive influence on tobermorite formation.
Lightweight Mortar Containing High Amounts of Alternative Raw Materials with Increased Thermal Resistance
Authors: Melichar Tomáš , Bydžovský Jiří , Dufka Ámos
Published: March 2018

The paper researches lightweight mortars based on a high content of alternative materials. 25 – 30% heating plant slag was used in order to modify the matrix. Fly ash agloporite (a lightweight aggregate produced by self-combustion from fly ash) was used as an aggregate. Mortars were exposed to the temperatures up to 1,250° C. Two types of cooling were carried out at 1,000° C; controlled slow (in the furnace) and by shock (in water baths of approximate 18° C). Developed materials were further analyzed by various methods: monitoring changes in an observation furnace, physical–mechanical (to determine strength properties), physical-chemical (phase composition - XRD) and microstructural (SEM).
Content of Aluminium Hydroxide in Lime-Silica Composite and its Influence on Tobermorite Formation
Authors: Melichar Jindřich , Černý Vit , Fleischhacker Jan , Drochytka Rostislav
Published: March 2018

Aerated concrete is lightweight building material with excellent thermos-technical properties compared to its strengths, easy workability and economic efficiency. It is material with long tradition of manufacturing since 1924 but its potential is yet possible to be extended. Since the beginning pure ingredients such as lime and silica sand has been used. Nowadays we are looking for ways to replace these expensive raw materials with cheaper alternatives. One of the most important mechanical properties of each material is its strength. In case of aerated concrete the bearer of strength is mineral tobermorite. It is created by reaction of silicon oxides and lime at hydrothermal conditions. It belongs to the group of calcium hydrosilicates with chemical formula Ca5Si6O16(OH)2·4H2O. Main goal of this paper is proposal for modification of the raw materials composition and autoclave regime of aerated concrete using aluminium hydroxide in order to improve final mechanical properties and mineralogical composition.
The Mechanical Properties and Micro-Structure of Oil Well Cement Enhanced by Graphene Oxide
Authors: Liu Hui Ting , Jin Jian Zhou , Yu Yong Jin , Liu Shuo Qiong
Published: March 2018

The improvement of strength and ductility is a challenging task for application of oil well cement. As a 2D nanomaterial with high strength and toughness, graphene oxide (GO) was used as a reinforcing additive in oil well cement. The mechanical properties and micro-structure of oil well cement enhanced by GO were investigated. The compressive strength and flexrual strenghth of cement stone both showed a good enhancement effect when the content of GO was 0.02% -0.05%. The compressive strength and flexrual strength could increase by 15.8% and 33.5%, respectively. The results of SEM and MIP revealed that GO played a template role in promoting the formation of hydration products and further filled in the pores between the hydration products, which refined the micro-structure and improved mechanical properties of the cement consequently.
Quantitative Experimental Study of SiO2-Water Nanofluids on Backward-Facing Step Flow under Low Reynolds Number
Authors: Lv Ji Zu , Li Liang Yu , Hu Cheng Zhi , Bai Min Li , Chang Sheng Nan , Gao Dong Dong , Wang Peng
Published: March 2018

Nanofluids is an innovative study of nanotechnology applied to the traditional field of thermal engineering. It refers to the metal or non-metallic nanopowder was dispersed into water, alcohol, oil and other traditional heat transfer medium, to prepared as a new heat transfer medium with high thermal conductivity. The role of nanofluids in strengthening heat transfer has been confirmed by a large number of experimental studies. Its heat transfer mechanism is mainly divided into two aspects. On the one hand, the addition of nanoparticles enhances the thermal conductivity. On the other hand, due to the interaction between the nanoparticles and base fluid causing the changes in the flow characteristics, which is also the main factor affecting the heat transfer of nanofluids. Therefore, a intensive study on the flow characteristics of nanofluids will make the study of heat transfer more meaningful. In this experiment, the flow characteristics of SiO2-water nanofluids in two-dimensional backward step flow are quantitatively studied by PIV. The results show that under the same Reynolds number, the turbulence of nanofluids is larger than that of pure water. With the increase of nanofluids volume fraction, the flow characteristics are constantly changing. The quantitative analysis proved that the nanofluids disturbance was enhanced compared with the base liquid, which resulting in the heat transfer enhancement.
Synthesis and Characterization of Zinc Oxide Nanoparticles for Application in the Detection of Fingerprints
Authors: Guzman Maribel , Flores Betty , Malet Loic , Godet Stephane
Published: March 2018

Stable zinc oxide nanoparticles were prepared by chemical process. Zinc oxide nanoparticles were synthesized using a modified method with zinc nitrate and sodium hydroxide at 60° C. The synthesized nanopowders were characterized in terms of chemical composition (EDS), structure FTIR and XRD, particle size and morphology by TEM. The XRD results confirm that ZnO nanoparticles were obtained with hexagonal arrangement (Wurtzite). The nanoparticles showed sizes between 10 to 30 nm and semispherical forms. The luminescent properties of the synthesized nanoparticles were measured in a photoluminescence assay on a Raman instrument. The samples were irradiated with two laser beams of different wavelengths. The application of the fingerprints on different surfaces was done using deferments surfaces.
A Permeability Model for Polymer-Clay Nanocomposites with Varying Clay Platelets Thickness
Authors: Al-Abduljabbar Abdulhamid
Published: March 2018

Polymer-clay nanocomposites (PCNC), are characterized by the high ratio of surface area to volume of the clay nanoparticles which are in the form of clay platelets with very high aspect ratio. This feature provides superior gas barrier properties at very low volume fraction of the nanofiller. Clay platelets introduce discontinuity to flows through the bulk polymer matrix material. The extent of this improvement depends on the success of separation of clay layers during processing which would produce single-layer particles (exfoliation) or several-layer particles (intercalation) through the bulk polymer matrix. This paper discusses the common permeability models used to capture the effects of the clay nanofillers in PCNC. Since these models assume a state of full exfoliation of clay platelets; that is a single phase of the nanofiller, they fall short of representing the actual state as evidenced by experimental works, which confirm the presence of both the intercalated phase and the exfoliated phase. A model that incorporates clay inclusions with different sizes (different thicknesses) is proposed and its implications are assessed.
Density Functional Calculation for BP/GaN Heterostructures
Authors: Özkişi Harun , Dalgıç Seyfettin
Published: March 2018

Recently, it has become indispensable to use semiconducting nanostructures in the production and development of electronic devices. In this study, the bulk and nanowire heterostructures of the BP / GaN system have been investigated for the structures pure and Te atom doped. In calculations, the plane wave self-consistent field program based on density functional theory was used. The average potentials of the aforementioned systems have been calculated and the interface effect has investigated.
Preparation of Cuprous Oxide/Cobaltous Oxide Nanostructured Composite with the Aid of Polyethylene Glycol and Ultrasonic Sound
Authors: Custodio Cyron L. , Untalasco John Lemuel G. , Marquez Menandro C.
Published: March 2018

Metal oxide semiconductors such as cobaltous oxide (Co3O4) and cuprous oxide (Cu2O) have caught the attention of many researchers due to their wide variety of applications. The attachment of Cu2O to Co3O4 was assisted by polyethylene glycol and the nanostructuring by ultrasonic sound. X-ray Diffraction (XRD) analysis of the fabricated composite reported characteristic peaks for crystalline Co3O4 and Cu2O. Results from Energy Dispersive X-ray (EDX) Spectroscopy showed the presence of cobalt, copper, and oxygen atoms which supports the result obtained in XRD. Cauliflower to nearly spherical shaped Cu2O - Co3O4 nanostructures were formed as observed in the Scanning Electron Micrographs (SEM) with a mean diameter of 0.5-1.0 μm. the shape of the composite and its surface morphology was altered with the use of different precursor materials for the synthesis of the Co3O4 seed. A blue shift in the UV-vis was observed upon the use of nitrate based precursor indicating the presence of smaller and finer particles in the composite. Overall results prove that Cu2O and Co3O4 can be synthesized using a facile solution approach with the aid of PEG and ultrasonic sound its application in the field of photocatalysis is probable.
Thermally Induced Morphological and Structural Transitions of Zinc Blende CdSe Hollow Nanoparticles Studied by Molecular Dynamics Simulation
Authors: Dalgic Serap Senturk
Published: March 2018

The morphological and structural transitions in CdSe hollow nanoparticles (hNPs) with zinc blende structure have studied by molecular dynamics (MD) simulation method under heating. The seven samples of CdSe-hNPs are constructed with different thicknesses from the solid NPs at 10nm and 15nm sizes. Morphological changes in CdSe-hNPs have presented by describing the first stage melting in hollow semiconductor NPs. The thermal effect on the atomic arrangement has also examined by the cubic zinc blende-to-wurtzite transformation occurred during the melting in hNPs. MD results show that the inner shells of those with thin walls have begun to melt at lower temperatures due to the thickness of the NPs. The first stage melting, which resulted in the filling of the void within the particle, takes place almost at the same temperature for hNPs with the thick wall thickness. Then, the melting of the particles is completed at higher temperatures. The cubic diamond structure disappears with the collapse of the inner cavity, and the hcp structure begins to appear at later temperatures.
Electronic Properties of Cr and Mn Doped BN Nanowires
Authors: Özkapı Sena Güler , Özkapı Barış , Dalgıç Seyfettin
Published: March 2018

In this work, we have investigated electronic structures of pure and doped (with Cr and Mn atoms, separately) BN nanowires along [001] direction with zinc blende phase by means of density functional theory calculations. Our results show that the substitution doping of nanowires by Cr and Mn atoms decrases the band gaps of the all BN nanowires. Also, spin polarized calculations exhibit that the density of states (DOS) for spin up and spin down electrons are antisymmetric structure for both Cr and Mn doped BN nanowires. All these show that doped BN nanowire systems have potential applications in electronics and spintronics.
Surfactant Assisted Sol-Gel Synthesis of Nickel Oxide Nanostructures
Authors: Mateo Jan Rommel C. , Salut Annalou L. , Marquez Menandro C.
Published: March 2018

This paper aims to find various ways to maximize the potential of nickel oxide (NiO) nanostructures which is produced via simple route method. The morphology of the NiO nanostructures was modified by adding surfactants such as Tween 80, SDS and CTAB. The effect on the morphology and optical property of the type and amount of the surfactant used were determined. The synthesized nanostructures were compared in terms of its shape, uniformity and size. SEM images revealed that the morphologies were altered by simply adding and adjusting the amount of surfactant such as CTAB, Tween 80 and SDS on to the solution. Nanocubic, nanospheres and nanoblades were produced using CTAB, Tween 80 and SDS respectively. XRD confirmed the presence of oxide and hdroxides of nickel on the produced product. The effects on the morphology of the NiO upon adding surfactant could give a good impact in different applications such as electrode, catalysts and gas sensors.
CCR7 on CD4+ T Cells Plays a Crucial Role in the Induction of Experimental Autoimmune Encephalomyelitis
Authors: Belikan Patrick , Bühler Ulrike , Wolf Christina , Pramanik Gautam K. , Gollan René , Zipp Frauke , Siffrin Volker
Published: March 2018

Multiple sclerosis (MS) is the most common chronic inflammatory demyelinating disease of the CNS. Myelin-specific CD4+ Th lymphocytes are known to play a major role in both MS and its animal model experimental autoimmune encephalomyelitis (EAE). CCR7 is a critical element for immune cell trafficking and recirculation, that is, lymph node homing, under homeostatic conditions; blocking CCR7+ central memory cells from egress of lymph nodes is a therapeutic approach in MS. To define the effect of CD4+ T cell–specific constitutive deletion of CCR7 in the priming and effector phase in EAE, we used an active EAE approach in T cell reconstituted Rag1−/− mice, as well as adoptive transfer EAE, in which mice received in vitro–primed CCR7−/− or CCR7+/+ myelin Ag TCR-transgenic 2d2 Th17 cells. Two-photon laser scanning microscopy was applied in living anesthetized mice to monitor the trafficking of CCR7-deficient and wild-type CD4+ T cells in inflammatory lesions within the CNS. We demonstrate that CD4+ T cell–specific constitutive deletion of CCR7 led to impaired induction of active EAE. In adoptive transfer EAE, mice receiving in vitro–primed CCR7−/− 2d2 Th17 cells showed similar disease onset as mice adoptively transferred with CCR7+/+ 2d2 Th17 cells. Using two-photon laser scanning microscopy CCR7−/− and CCR7+/+ CD4+ T cells did not reveal differences in motility in either animal model of MS. These findings indicate a crucial role of CCR7 in neuroinflammation during the priming of autoimmune CD4+ T cells but not in the CNS.
CXCL17 Chemokine–Dependent Mobilization of CXCR8+CD8+ Effector Memory and Tissue-Resident Memory T Cells in the Vaginal Mucosa Is Associated with Protection against Genital Herpes
Authors: Srivastava Ruchi , Hernández-Ruiz Marcela , Khan Arif A. , Fouladi Mona A. , Kim Grace J. , Ly Vincent T. , Yamada Taikun , Lam Cynthia , Sarain Sheilouise A. B. , Boldbaatar Undariya , Zlotnik Albert , Bahraoui Elmostafa , BenMohamed Lbachir
Published: March 2018

Circulating conventional memory CD8+ T cells (i.e., the CD8+ effector memory T [TEM] cell and CD8+ central memory T [TCM] cell subsets) and the noncirculating CD8+ tissue-resident memory T (TRM) cell subset play a critical role in mucosal immunity. Mucosal chemokines, including the recently discovered CXCL17, are also important in mucosal immunity because they are homeostatically expressed in mucosal tissues. However, whether the CXCL17 chemokine contributes to the mobilization of memory CD8+ T cell subsets to access infected mucosal tissues remains to be elucidated. In this study, we report that after intravaginal HSV type 1 infection of B6 mice, we detected high expression levels of CXCL17 and increased numbers of CD44highCD62LlowCD8+ TEM and CD103highCD8+ TRM cells expressing CXCR8, the cognate receptor of CXCL17, in the vaginal mucosa (VM) of mice with reduced genital herpes infection and disease. In contrast to wild-type B6 mice, the CXCL17−/− mice developed 1) fewer CXCR8+CD8+ TEM and TRM cells associated with more virus replication in the VM and more latency established in dorsal root ganglia, and 2) reduced numbers and frequencies of functional CD8+ T cells in the VM. These findings suggest that the CXCL17/CXCR8 chemokine pathway plays a crucial role in mucosal vaginal immunity by promoting the mobilization of functional protective CD8+ TEM and CD8+ TRM cells, within this site of acute and recurrent herpes infection.
Kounis syndrome, a disease to know: Case report and review of the literature
Authors: Sciatti Edoardo , Vizzardi Enrico , Cani Dario S. , Castiello Assunta , Bonadei Ivano , Savoldi Daria , Metra Marco , D'Aloia Antonio
Published: March 2018

The case deals with an anaphylactoid reaction to intravenous ampicillin/sulbactam resulting in cardiogenic syncope and myocardial damage. Symptoms and ECG modifications promptly disappeared after corticosteroids administration. The Kounis syndrome is an acute coronary syndrome, including coronary spasm, acute myocardial infarction and stent thrombosis, resulting from an anaphylactic or anaphylactoid or allergic or hypersensitivity insult. First described in 1991, it can be caused by a lot of substances, particularly antibiotics. The management should be directed to both the allergic reaction and the myocardial damage. The Kounis syndrome is a not rare disease that every physician should know because of the wideness of triggers and the possible fatal evolution if not promptly recognized.
Stereoacuity and refractive, accommodative and vergence anomalies of South African school children, aged 13–18 years
Authors: Wajuihian Sam O. , Hansraj Rekha
Published: March 2018

Aim: The aim of this study was to explore possible associations between stereoacuity and refractive, accommodative and vergence anomalies.Methods: The study design was cross-sectional and comprised data from 1056 high school children aged between 13 and 18 years; mean age and standard deviation were 15.89 ± 1.58 years. Using a multi-stage random cluster sampling, participants were selected from 13 high schools out of a sample frame of 60 schools in the municipality concerned. In the final sample, 403 (38%) were males and 653 (62%) females. Refractive errors, heterophoria, near point of convergence, fusional vergences and accommodative functions (amplitude, facility, response and relative) were evaluated. Stereoacuity was evaluated using the Randot stereotest and recorded in seconds of arc where reduced stereoacuity was defined as worse than 40 s arc.Results: Overall, the mean stereoacuities (in seconds of arc) of the children with anomalies were the following: those with refractive errors (52.6 ± 36.9), with accommodative anomalies (53.1 ± 34.1) and with vergence anomalies (48.29 ± 31.1). The mean stereoacuity of those with vergence anomalies was significantly better than that of those with either refractive errors or accommodative anomalies (p = 0.02). In the refractive error category, only anisometropia had significantly reduced mean stereoacuity compared to emmetropia (Mann–Whitney U: p = 0.01). The mean stereoacuity of cases of accommodative anomalies was significantly reduced compared to those without such anomalies (Mann–Whitney U: p = 0.01). Similarly, the mean stereoacuity of cases with vergence anomalies was significantly reduced compared to those without vergence anomalies (p = 0.02).Conclusion: Refractive errors, accommodative or vergence anomalies are more likely to have reduced mean stereoacuity than cases without such anomalies. Refractive errors or accommodative anomalies had significantly more reduced stereoacuity than vergence anomalies. These findings suggest that the Randot stereotest could be used to identify those with such anomalies, and this study extends knowledge regarding the possible use of stereoacuity as a useful tool to screen for binocular anomalies.
Aligners: the Invisible Corrector—A Boon or Bane
Authors: Mahendra Lodd
Published: March 2018

How to cite this article: Mahendra L. Aligners: the Invisible Corrector—A Boon or Bane. J Contemp Dent Pract 2018;19(3):247.
Assessment of Salivary Catalase, α-Amylase, and Cotinine Levels in Chronic Smokers: A Comparative Study
Authors: Singh Satvinder , Sharma Mamta , Rohilla Nitika , Salgotra Varun , Kumar Varun , Sharma Rahul K
Published: March 2018

Introduction

One of the common practices observed in many parts of the world is smoking, of which tobacco forms an important constituent which is burned and inhaled. Smoking is known to have potential effect on body’s immune system, antioxidants level, and salivary cotinine levels. Hence, we planned the present study to evaluate the impact of cigarette smoke on salivary antioxidant levels and cotinine levels in smokers and nonsmokers.

Materials and methods

The present study included assessment of salivary parameters of smokers and nonsmokers. A total of 400 subjects were analyzed, of which 200 were active smokers and 200 were nonsmokers. Unstimulated salivary samples were taken and assessment of α-amylase levels was done using biochemical kit and spectrophotometer. Assessment of salivary catalase (CAT) activity was done using Luck method. For the determination of cotinine levels, Bioassay Technology Laboratory kit was used using enzyme-linked immunosorbent assay (ELISA) technique. After the assessment of levels of all the salivary parameters, all the data were recorded, compiled, and analyzed.

Results

α-Amylase in smokers and nonsmokers group was found to be 206.25 and 169.85 U/mL respectively. Nonsignificant results were obtained while comparing the salivary α-amylase levels among the two study groups. Nonsignificant results were obtained while comparing the salivary CAT levels among the smokers and nonsmokers group. We observed statistically significant results while comparing mean cotinine levels among smokers group and nonsmokers group.

Conclusion

Alteration in cotinine levels occurs in smokers in comparison to nonsmokers.

Clinical significance

Smoking can cause harmful effect on the oral mucous membrane by altering salivary defense components.

How to cite this article

Singh S, Sharma M, Rohilla N, Salgotra V, Kumar V, Sharma RK. Assessment of Salivary Catalase, α-Amylase, and Cotinine Levels in Chronic Smokers: A Comparative Study. J Contemp Dent Pract 2018;19(3):253-256.
Arab Societal Awareness of Dental Veneers
Authors: Alfouzan Afnan , Al-Sanie Aisha A , Al-Dhafiri Reem A
Published: March 2018

Aim

The aim of this study is to assess the Arab society’s knowledge, awareness, and attitudes toward dental veneers.

Materials and methods

A cross-sectional study was performed by collecting data through an online questionnaire created using the Survey Monkey website and distributed among Middle Eastern societies through social media to ascertain participants’ knowledge and awareness regarding dental veneers. The sample included Arab laypeople who were over 18 years old, to represent the awareness of the majority regarding dental veneers.

Results

The sample of this study included 1,332 subjects from different Middle Eastern nationalities, mainly Saudis, Kuwaitis, and Emiratis (15.6% of males and 84.4% of females). The results of this study showed that the total knowledge of dental veneers is 50.12%. The respondents with the highest level of knowledge acquired their information mainly from newspapers and magazines, followed by the Internet, then dentists, then social media, and, finally, friends and relatives.

Cost was the only factor limiting 38.4% of subjects from receiving veneers, and 56% of the subjects would receive veneers if they were free of cost. In total, 72.6% of the respondents believed that veneers are currently overused.

Conclusion

The knowledge and awareness of dental veneers were below a satisfactory level. Participants who relied on social media as a source of information had lower knowledge levels.

Clinical significance

This study emphasized the need for continual societal education regarding dental veneers.

How to cite this article

Alfouzan A, Al-Sanie AA, Al-Dhafiri RA. Arab Societal Awareness of Dental Veneers. J Contemp Dent Pract 2018;19(3):257-261.
Evaluation of the Efficacy of Different Mixing Techniques and Disinfection on Microbial Colonization of Polyether Impression Materials: A Comparative Study
Authors: Sharma Rajni , Pachar Renu B , Singla Youginder , Poriya Sangeeta , Mishra Aalok , Garg Anshu
Published: March 2018

Aim

This study aims to determine the role of mixing techniques of polyether impression materials and efficacy of disinfection on microbial colonization of these impression materials.

Materials and methods

Polyether impression material was mixed using two methods: First by hand mixing (group I) and second using an automixer (group II) with a total of 100 samples. Four microbial strains were studied, which included Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. After incubation, the bacterial colonies were counted, and then, disinfectant solution was applied. The effect of disinfection solution was evaluated for each specimen.

Results

The surface of polyether impression materials mixed with an automixer has less number of voids and overall a smoother surface as compared with the hand-mixed ones. On comparing the disinfection procedures, i.e., specimens without any disinfection and specimens after disinfection, statistically highly significant difference was seen between all the groups.

Conclusion

We can conclude that impression mixing procedures are important in determining the surface characteristics of the impression and ultimately the colonization of bacteria and also determine the importance of disinfection on microbial colonization.

Clinical significance

This study emphasises the deleterious role of nosocomial infections and specific measures that should be taken regarding the prevention of such diseases. Dental impressions are proved to be a source of such infections and may lead to transmission of such diseases. Thus, proper measures should be taken right from the first step of impression taking to minimizing and preventing such kind of contaminations in clinical practice.

How to cite this article

Singla Y, Pachar RB, Poriya S, Mishra A, Sharma R, Garg A. Evaluation of the Efficacy of Different Mixing Techniques and Disinfection on Microbial Colonization of Polyether Impression Materials: A Comparative Study. J Contemp Dent Pract 2018;19(3):296-300.