bluuebunny/crossref_metadata_2025 huggingface dataset:
Grinding of Austempered Ductile Iron Grade 3 as Function of the Microcrystalline Al2O3 Grinding Wheels Composition
Authors: Benini Lucas , Weingaertner Walter Lindolfo , Uhlmann Eckart
Published: May 2015

The conventional grinding wheels employment is an economically viable alternative on Austempered ductile iron (ADI) grinding. The machining of this iron is in most cases performed with superabrasive grinding wheels, requiring machine tools with higher costs. The ADI grinding with conventional grinding wheels can produce work results comparable to the superabrasive grinding wheels, followed by lower costs and flexibility in profile grinding, since these wheels can be easily re-profiled. The aim of this work is to verify the work results of grinding ADI Grade 3 employing conventional grinding wheels. The approach is based on the influence evaluation of different abrasive microcrystalline Al2O3 percentage in these tools on the force results and roughness values in the ADI grinding. The findings show a correlation between the grinding forces and the microcrystalline abrasive percentage of microcrystalline Al2O3, since lower forces were demanded for wheels with higher percentages. Regarding the surface parameters, there was a decrease in roughness values by employing less percentages. The originality of this research is reflected in the fact that it is the first time that the influence of the composition of conventional grinding wheels is investigated on ADI Grade 3 grinding. The results present in this research will contribute to the most appropriate conventional grinding wheel specification for the ADI Grade 3 grinding.
MoS2: Advanced Nanofillers for Polymer Nanocomposites
Authors: Zhou Ke Qing , Gui Zhou , Hu Yuan
Published: May 2015

Since discovery of graphene, great attention had been paid to other two dimensional (2D) layered materials. As a graphene-like layered nanomaterial, molybdenum disulfide (MoS2) had gained enormous attention from the materials fields which had been widely used in many areas such as solid lubricants, lithium ion batteries, photocatalysts, sensors or as conductive fillers in polymer composites. In this work, MoS2 nanosheets were incorporated into polymer matrix as nanofillers by three typical preparation methods, including solvent blending, in situ polymerization and melt blending method. The MoS2 nanosheets were dispersed well in the polymer matrices which improved the thermal stability, mechanical properties and reduced fire hazards of the composites obviously. The improvements in the thermal properties, fire resistance properties and mechanical properties of polymer/MoS2 nanocomposites were mainly attributed to good dispersion of MoS2, physical barrier effects of MoS2 and catalytic char function of MoS2 nanosheets.
UV-Assisted Synthesis of Silver Nanoparticles Using Poly(Acrylic Acid) for Colorimetric Ammonia Sensing
Authors: Detsri Ekarat , Popanyasak Jittaporn , Laomaneenopparat Nathawut , Warngbun Kittima
Published: May 2015

Silver nanoparticles was successfully synthesized by the exposure of silver nitrate solution to the high intensity ultraviolet source with an addition of poly (acrylic acid, sodium salt), (PAA) as the stabilizing agent. The silver nanoparticles were displayed a dark blue color which a maximum absorbance at 784 nm. The average size and surface charges of PAA stabilized silver nanoparticles at pH5 were 81.62 nm and-14.32 mV, respectively. Upon the addition of ammonia solution, the dark blue color of silver nanoparticles were changed to light green and yellow. The detection of ammonia concentration using PAA stabilized silver nanoparticles has been responded to 1-80 ppm. The PAA stabilized silver nanoparticles, blue solution are promising to be an alternative method for colorimetric detection of ammonia in environmental or industrial section.
Numerical Modelling of the Interaction Macro–Multimicrocracks in a Pipe under Tensile Stress
Authors: Sahnoun Mohamed , Ouinas Djamel , Bouiadjra B. Bachir , Olay J. Vina , Vina Olay J.
Published: May 2015

In this paper, the evaluation of the SIFof a macrocrack in interaction with one or several microcracks in a material containing a geometrical defect was investigated. Several configurations were considered in order to apprehend the mechanisms induced by the interaction effect and in particular the effects of reduction and/or amplification of the stress field between macro and single or multiple microcracks. The obtained results show that, macro–microcrack spacing is an important parameter if the microscopic crack is relatively close to the macrocrack-tip. The macrocrack has the tendency to accelerate as it propagates towards the microcrack. When the relative distance characterizing this spacing is higher than 0.3, the interaction effect can be neglected and the SIF remains unchanged for both defect types. When this ratio is lower than 0.3, the interaction between the two defects becomes significant and the stress intensity factor at the macrocrack tip strongly increases.
2-(Methacryloyloxyethyl) Trimethyl Ammonium Chloride Grafted onto Natural Rubber in Latex State
Authors: Klinpituksa Pairote , Chekmae Nurhayatee , Borthoh Salinee
Published: May 2015

The grafting of polar vinyl monomers onto natural rubber is usually investigated to modify specific properties of natural rubber. The aim of this research was to graft copolymerize 2-(methacryloyloxyethyl) trimethyl ammonium chloride (MAETAC) onto natural rubber (NR), using cumene hydroperoxide (CHP) and tetraethylene pentamine (TEPA) as a redox initiator system. The effects of the initiator system, the monomer, and the reaction temperature and time on grafting were investigated. The grafted product was characterized by FTIR spectrophotometry. The grafting tendency was determined by using the relative absorbance ratio of A1725/A842, which compares the C=O stretching in MAETAC with the =CH out-of-plane bending in natural rubber moieties. Near optimal grafting was obtained with CHP and TEPA both at 0.15 phr, monomer at 20 phr, reacted at 65°C for 120 minutes. The grafting percentage of NR-g-MAETAC was 6.10 as determined by ATR-FTIR.
Electroactive Polymer Actuator Based on PVDF and Graphene through Electrospinning
Authors: Wang Fan , Ko Seong Young , Park Jong Oh , Park Suk Ho , Kee Chang Doo
Published: May 2015

We report a novel high-performance electroactive polymer actuator based on poly (vinylidene fluoride) (i.e., PVDF) and graphene. The PVDF-graphene composite membranes were fabricated through electrospinning method. The electrospun composite membrane has a three-dimensional network structure, high porosity, and large ionic liquid solution uptake which are a prerequisite for high performance dry-type electroactive soft actuators. The conductive poly (3,4-ethylenedioxythiophene)-poly (styrenesulfonate) (PEDOT:PSS) layers were deposited on the surfaces of the composite membrane through dipping-drying method. The electroactive PVDF-graphene actuators under both harmonic and step electrical inputs show larger bending deformation and faster response time than the pure PVDF actuator. X-ray diffusion (XRD) and ionic conductivity testing results for the PVDF-graphene membrane were compared with those of pristine PVDF. Most important, the PVDF-graphene actuator shows much larger bending deformation under low input voltage, and this could be due to the synergistic effects of the higher ionic conductivity of PVDF-graphene membrane and the electrochemical doping processes of the PEDOT:PSS electrode layers.
Plastic Waste in Cement Concrete, LDPE and PVC Introduction Effect
Authors: Merbouh M'hammed , Glaoui Bachir
Published: May 2015

We checker huge quantities of plastic with various forms and types. Major problems caused by these wastes in nature, inside the urban areas and countryside, impose a concern of increasing difficulties for reasons of hygiene and environment
Cement concrete is a relatively inert and durable material, compact and waterproof, which can prevent contamination of the environment by living the harmful effects of plastic.
In this context it was considered appropriate to include in concrete composition the elements of plastic waste (bag: LDPE) and (bottle: PVC) as a technique for recovery and reuse it’s in the cost. It is a simple and clean procedure to remove these dangerous elements and participate to preserve the nature.
Results showed the possibility of using these types of plastic at ambient condition, as a substitution of aggregates, with a slight decrease in compressive strength on the percentage of substitution and an optimal increase in tensile resistance associated with a substantial gain in weight and a high removal rate, especially for PVC.
These materials may be intended for the manufacture of components requiring less performance (small works, architectural concrete and decorative elements of the interior, filling, surface coverage and roof.).
Wettability-Based Colorimetric Test Strips for Gasoline/Oil Mixture Differentiation
Authors: Qiu Shuang , Wong Michael Chung Kay , Li Paul Chi Hang
Published: May 2015

As inspired by the pH paper for the determination of the acidity levels of solutions, we have developed a wettability-based colorimetric test strip to differentiate the composition of gasoline/oil mixtures. These mixtures are widely used in two-stroke motor engines. A method that is rapid, low cost and simple-to-use will facilitate the differentiation of these gasoline/oil mixtures, and ensure the use of these mixtures in the proper ratios in two-stroke engines for optimized engine performance and endurance. An inverse opal film (IOF) consisting of nanopores was synthesized on the silicon strips. These strips were then functionalized with alkysilanes through chemical vapor deposition. Based on the observation that the silanized nanopores are wetted or not wetted by the gasoline/oil mixtures, we are able to differentiate between the 16:1 and 1:1 mixtures.
High and Low Speed Impact Characteristics of Nanocomposites
Authors: Aldajah Saud , Haik Yousef , Moustafa Kamal , Alomari Ammar
Published: May 2015

Nanocomposites attracted the attention of scientists due to their superior mechanical, thermal, chemical and electrical properties. This research studied the impact of adding carbon nanotubes (CNTs) to the woven Kevlar laminated composites on the high and low speed impact characteristics. Different percentages of CNTs were added to the woven Kevlar-Vinylester composite materials. An in-house developed drop weight testing apparatus was utilized for the low speed impact testing. Two different concentrations of the CNTs were added to a 15-layer woven Kevlar laminates, 0.32 wt% and 0.8 wt%. The results showed that: The 0.32 wt % CNT sample enhanced the interlaminar strength of the composite without enhancing the energy absorption capacity whereas, the 0.8 wt % CNT sample did not improve the impact resistance of the Kevlar composite.For the high speed impact tests, a bulletproof vest was prepared using woven Kevlar, resin, and CNTs at 1.5 w% percentage. The ballistic shooting was carried out by a professional shooter using a 30 caliber and 9 mm bullets for the tests. The CNT bulletproof sample bounced back the 30 caliber copper alloy bullet with no penetration.
Effects of Sputtering Pressure on Cu3N Thin Films by Reactive Radio Frequency Magnetron Sputtering
Authors: Ji Xiao Lin , Ju Hai Dong , Zou Tao Yu , Luo Jin Long , Hong Kun Quan , Yang Hai , Wang Hai
Published: May 2015

Copper nitride thin films were prepared by reactive radio frequency magnetron sputtering at different sputtering pressures with fixed nitrogen to argon ratio. The influences of sputtering pressure on the structure, optical band gap, and surface morphology of films were investigated. The results show that the preferential orientation of polycrystalline Cu3N thin films changes from [111] to [100] when the sputtering pressure increases. Meanwhile, the optical band gap (Eg) of Cu3N thin films increases with the sputtering pressure. The surface morphology of Cu3N thin film deposited at high sputtering pressure becomes smoother than that of Cu3N thin film deposited at low sputtering pressure.
Application of Stereological Relations for the Characterization of Porous Materials via Microscopic Image Analysis
Authors: Uhlířová Tereza , Gregorová Eva , Pabst Willi
Published: May 2015

In this work we demonstrate the application of stereology-based image analysis for the characterization of highly porous cellular ceramics (alumina foams) prepared by biological foaming with yeast and subsequent drying (80-105 °C) and firing (1570 °C). It is shown that the ceramics prepared usually have total porosities in the range 78-84 % and that the porosities made up by large pores (volume fraction of foam bubbles) are usually in the range 58-75 %. Further it is shown that the mean chord length and the Jeffries size, i.e. pore size measures related to the interface density and the mean curvature integral density, respectively, are relatively close to each other (usually 0.8-1.4 and 0.8-1.2 mm) with a ratio close to unity (0.9-1.3) and that the mean surface-to-surface distance of pores gives a realistic picture of the average pore wall thickness (usually 0.46-0.69 mm). Using a special processing variant (excess ethanol addition) it is possible to obtain microstructures with lower porosity (total porosity 68-70 %, foam bubble volume fractions 50-56 %) and smaller pore size (approx. 0.5 mm). Absolute errors are calculated using normalized deviations corresponding to 95 % reliability in the Student distribution and the standard errors for the quantities in question (both observed and estimated). Relative errors are found to be below 12 % when the number of measurements is of order 400-1000.
Porosity Quatification of Cast Aluminium Alloys on Machined Surfaces Using Metallography and Eddy-Currents
Authors: Skrbek Břetislav
Published: May 2015

The porosity is unwanted phenomenon mostly that is tried to eliminate. The pores are initiation site of fatigue fractions usually, they worse strength and ductility of materials, quality of machined surfaces and their following surface treatment.
Metallographic and Acoustic Analyses of Sintered Sliding Layers
Authors: Skrbek Břetislav
Published: May 2015

The aim of this contribution is to propose acceptable ultrasound diagnostic methods which should help discover products with excessive porosity of sintered sliding layer on bearing shells which causes low bearing durability by means of measuring of samples taken from bearing shells manufactured by commercial companies in Slovakia and Germany.
Chain Segment Analysis
Authors: Jech David , Klakurková Lenka , Čelko Ladislav , Doležal Pavel , Švejcar Jiří
Published: May 2015

The work is aimed at a detailed analysis of impaired chain segments manufactured by welding and determining the cause of chain segment failure. The main interest was focused on the base material structure, the quality of weld joint, the heat treatment of the weldment, and the overall condition of the component after operating workload. The chain segments were investigated in terms of the microstructure by means of the light microscope, scanning electron microscope equipped with an energy dispersive microanalyser, and hardness measurement.
Analysis of Cracked Spring Washer for Sleeper-Rail Joints
Authors: Pavloušková Zina , Man Ondřej , Horynová Miroslava , Čelko Ladislav , Švejcar Jiří
Published: May 2015

The paper deals with the qualitative, quantitative, and phase analyses of particles that were found during the metallographic analysis of a cracked spring washer made of silicon spring steel 38Si7, with the aim of ruling out the client’s suspicion of possible initiation of graphitization in the course of the heat treatment. The problem is solved via metallographic analysis using light microscopy, scanning electron microscopy including EDS microanalysis of the chemical composition and EDS line analysis.
Various Approaches to Accelerated Carbide Spheroidization of 54SiCr Steel
Authors: Kučerová Ludmila , Jirková Hana , Mašek Bohuslav
Published: May 2015

Changing the lamellar morphology of pearlite to a globular morphology significantly enhances the formability of pearlite-ferrite steels. This change is conventionally achieved by soft annealing. Annealed structures possess low yield strength and excellent ductility and this ensures their good cold formability. The problems of these technologies lie not only in long processing times, but also in high energy consumption which makes the final product quite expensive. The time necessary for cementite spheroidization can be shortened by unconventional heat treatment around Ac1 temperature combined with deformation applied at various processing stages. Several processing methods were utilized for spring steel 54SiCr with ferrite-pearlite original microstructure and lamellar pearlite morphology. The hardness of this structure reached 290 HV10. Three main strategies were tested in this work, using either tensile and compression deformation with following hold applied at heating temperature, temperature cycling around AC1 temperature, or deformation cycles applied at heating temperature. First of all, various heating temperatures in the region of 680-740°C were tested to determine the most suitable heating temperature for this steel. Subsequently, the influence of the character and intensity of applied deformations on cementite spheroidization and ferrite grain refinement were investigated. Carbide morphology and distribution were determined by the means of light and scanning electron microscopy and mechanical properties were determined by hardness measurement. Spheroidized carbides evenly distributed in fine ferrite matrix were obtained after the optimization of processing parameters.
RECENT ADVANCES IN THE 5Q- SYNDROME
Authors: Pellagatti Andrea , Boultwood Jacqueline
Published: May 2015

The 5q- syndrome is the most distinct of the myelodysplastic syndromes (MDS) and patients with this disorder have a deletion of chromosome 5q [del(5q)] as the sole karyotypic abnormality. Several genes mapping to the commonly deleted region of the 5q- syndrome have been implicated in disease pathogenesis in recent years. Haploinsufficiency of the ribosomal gene RPS14 has been shown to cause the erythroid defect in the 5q- syndrome. Loss of the microRNA genes miR-145 and miR-146a has been associated with the thrombocytosis observed in 5q- syndrome patients. Haploinsufficiency of CSNK1A1 leads to hematopoietic stem cell expansion in mice and may play a role in the initial clonal expansion in patients with 5q- syndrome. Moreover, a subset of patients harbor mutation of the remaining CSNK1A1 allele. Mouse models of the 5q- syndrome, which recapitulate the key features of the human disease, indicate that a p53-dependent mechanism underlies the pathophysiology of this disorder. Importantly, activation of p53 has been demonstrated in the human 5q- syndrome. Recurrent TP53 mutations have been associated with an increased risk of disease evolution and with decreased response to the drug lenalidomide in del(5q) MDS patients. Potential new therapeutic agents for del(5q) MDS include the translation enhancer L-leucine.
Healthcare provider and patient perspectives on diagnostic imaging investigations
Authors: Makanjee Chandra R. , Bergh Anne-Marie , Hoffmann Willem A.
Published: May 2015

Background: Much has been written about the patient-centred approach in doctor–patient consultations. Little is known about interactions and communication processes regarding healthcare providers’ and patients’ perspectives on expectations and experiences of diagnostic imaging investigations within the medical encounter. Patients journey through the health system from the point of referral to the imaging investigation itself and then to the post-imaging consultation.Aim and setting: To explore healthcare provider and patient perspectives on interaction and communication processes during diagnostic imaging investigations as part of their clinical journey through a healthcare complex.Methods: A qualitative study was conducted, with two phases of data collection. Twenty-four patients were conveniently selected at a public district hospital complex and were followed throughout their journey in the hospital system, from admission to discharge. The second phase entailed focus group interviews conducted with providers in the district hospital and adjacent academic hospital (medical officers and family physicians, nurses, radiographers, radiology consultants and registrars).Results: Two main themes guided our analysis: (1) provider perspectives; and (2) patient dispositions and reactions. Golden threads that cut across these themes are interactions and communication processes in the context of expectations, experiences of the imaging investigations and the outcomes thereof.Conclusion: Insights from this study provide a better understanding of the complexity of the processes and interactions between providers and patients during the imaging investigations conducted as part of their clinical pathway. The interactions and communication processes are provider–patient centred when a referral for a diagnostic imaging investigation is included.
Factoring a Quadratic Operator as a Product of Two Positive Contractions
Authors: Li Chi-Kwong , Tsai Ming-Cheng
Published: May 2015

Let T be a quadratic operator on a complex Hilbert space H. We show that T can be written as a product of two positive contractions if and only if T is of the form

for some a, b ∊ [0, 1] and strictly positive operator P with . Also, we give a necessary condition for a bounded linear operator T with operator matrix on H⊕K that can be written as a product of two positive contractions.
Contemporary Challenges of Access to Information in Public Governance in South Eastern Europe
Authors: Kovač Polonca
Published: May 2015

Access or right to information (RTI) is a fundamental principle in a democratic society. Most countries, particularly in the EU, regulate such institution by law, making a distinction between access to file within administrative procedures and access to public information. The article provides a normative and comparative study of the RTI regulation in Slovenia, Serbia and Croatia as South Eastern European countries. The dilemmas arising in the practical implementation thereof are analyzed as well. In the respective area, the degree of awareness of the need for open and good administration governance is rather high, taking into account EU guidelines, yet regulation alone does not suffice and should be followed by effective implementation to overcome still undergoing processes of Europeanization and (post)transition and develop good administrative governance.
Factors explaining the Impact of Performance Measures in European Local Governments
Authors: Torres Lourdes , Pina Vicente , Martí Caridad
Published: May 2015

This paper seeks to identify the drivers of the variations in the impact perceived by managers of the implementation of performance measures (PM) across European local governments. We argue that insights from the use of PM for managerial processes and human resources (HR) management features condition the perceived impact of PM systems. The data was collected through a questionnaire answered by local governments of 16 European countries. The results show that the higher the use of PM in performance-oriented budgeting processes, the higher the impact of PM on improvements in the quality of decision-making. Monetary incentives linked to performance better explain the actual results in PM implementation than the kind of HR system of the cities and the academic backgrounds of their senior managers.
The Potential of Dynamic Enterprises in Job Creation in Slovenian Regions
Authors: Novak Riko , Pšeničny Viljem
Published: May 2015

Due to their above average growth, dynamic enterprises contribute significantly to general economic growth, especially in the field of job creation and the investment cycle. Therefore this article presents the potential of dynamic enterprises for the creation of jobs in selected Slovenian statistical regions. The empirical findings are divided into three different researched periods, namely for the period between 2006 and 2010, the period between 2007 and 2011, and the period between 2008 and 2012 on a population of 4,511, 4,380, and 3,725 dynamic enterprises respectively, taken from the entire national statistics database managed by AJPES (Agency of the Republic of Slovenia for Public Legal Records and Related Services) on the basis of 13 previously determined criteria. The objective of this article is twofold: In the first stage, it aims to present the dispersion of dynamic enterprises in different Slovenian regions based on a previously conducted qualitative and quantitative study, and in the second stage to show their potential for job creation. All in all, it was established that the analysed dynamic enterprises created all the net new jobs in the Slovenian national economy during the crisis (in the period between 2009 and 2012).
Planning Oral Health and Clinical Discharge in Primary Care: The Comprehensive Dental Care Protocol Outcome
Authors: Cavalcanti Yuri Wanderley , de Almeida Leopoldina de Fátima Dantas , de Souza Barbosa Ailma , Padilha Wilton Wilney Nascimento
Published: May 2015

Introduction

The dental care must be driven by preventive and curative measures that can contribute to the population's oral health promotion.

Objective

To evaluate the impact of the actions proposed by a comprehensive dental care protocol (CDCP) on the oral health condition of primary care users.

Materials and methods

The sample consisted of 32 volunteers, assisted throughout the six phases proposed by the CDCP: diagnosis of dental needs; resolution of urgencies; restorative interventions; application of promotional measures; evaluation of the achieved health level; and periodic controls. Data were collected through clinical exams, which measured the simplified oral hygiene index (OHI-S), gingival bleeding index (GBI) and the decayed, missing and filled teeth (DMFT) Index, before and after the CDCP was implemented. Statistical analysis consisted of the Wilcoxon test, at 5% significance level (α = 0.05).

Results

The OHI-S and GBI indices showed a significant reduction (p < 0.05) from the initial (1.4 ± 0.6 and 46.3 ± 19.9) to final condition (0.9 ± 0.3 and 21.5 ± 7.5). The decayed, missing and filled teeth and the missing teeth component were not significantly altered (p > 0.05), showing final values equal to 12.7 ± 9.6 and 5.6 ± 7.8, respectively. Decayed elements were fully converted into filled elements, and the final values of the decayed and filled elements were, respectively, 0.0 ± 0.0 and 7.3 ± 5.7 (p < 0.05).

Conclusions

The enactment of the CDCP had a beneficial effect on the oral health of the population assisted by the dental services offered in primary care and this protocol seems to fit the public dental service demands.

Clinical significance

The CDCP can be useful to public dental service planning since it showed an efficient clinical outcome to the patients. We consider that this protocol should be employed in primary care oral health services in order to achieve overall upgrade, access enlargement and public oral health promotion.

How to cite this article

Cavalcanti YW, de Fátima Dantas de Almeida L, de Souza Barbosa A, Padilha WWN. Planning Oral Health and Clinical Discharge in Primary Care: The Comprehensive Dental Care Protocol Outcome. J Contemp Dent Pract 2015;16(3):172-177.
Evaluation of the Influence of Three different Temperatures on Microleakage of Two Self-etch and One Total-etch Adhesives
Authors: Akbarian Sahar , Sharafeddin Farahnaz , Akbarian Golsa
Published: May 2015

Aim

To evaluate the bonding temperature effect on dentinrestoration microleakage.

The null hypothesis of the study is that the score of microleakage is identical among different adhesive bondings at different temperatures.

Materials and methods

Ninety caries free maxillary premolars were selected. Class V cavities were prepared on the cemento enamel junction (CEJ) of the buccal sides with enamel margins on occlusal sides and cementum margins on gingival sides. The specimens were divided into 3 groups: G1, single bond adhesive + Z250 composite; G2, P90 adhesive + Filtek Silorane composite; and G3, Clearfil SE bond + Clearfil APX. All groups were divided into three subgroups based on the adhesive temperature: A—4°C; B—25°C; and C—40°C. After coating the specimens with nail polish 1 mm beyond the margin of the restorations, they were stored in 0.5% basic Fuchsin dye solution for 24 hours. The teeth then were buccolingually sectioned and observed under a stereomicroscope.

Results

There was no significant difference between microleakage of occlusal and gingival margins in each group. Clearfil SE bond and Adper single bond displayed lower microleakage than P90 adhesive at 4°C and 25°C. The most and least microleakage score for Adper single bond was at 40°C and 25°C respectively. Clearfil SE bond showed less microleakage at 25°C than 4°C and 40°C.

Conclusion

Clearfil SE bond and Adper single bond displayed less microleakage at 25°C while there was no significant difference among for P90 adhesive microleakage at three temperatures.

How to cite this article

Akbarian S, Sharafeddin F, Akbarian G. Evaluation of the Influence of Three different Temperatures on Microleakage of Two Self-etch and One Total-etch Adhesives. J Contemp Dent Pract 2015;16(3):178-182.
Evaluation of Different Irrigating Solutions on Smear Layer Removal of Primary Root Dentin
Authors: Balto Hanan , Salama Fouad , Al-Mofareh Sultan , Al-Yahya Faisal
Published: May 2015

Aim

To evaluate the efficacy of ethanolic extract of Salvadora persica (S. persica) and BioPure MTAD (a mixture of a tetracycline isomer, an acid, and a detergent) in removing the intracanal smear layer of primary teeth.

Materials and methods

The root canal of 40 extracted human primary anterior teeth were cleaned, shaped and grouped into experimental (n = 30) and control (n = 10). The root canals of the positive (n = 5) and the negative control (n = 5) were irrigated for 3 minutes with 5 ml of 17% ethylenediaminetetraacetic acid (EDTA) or saline respectively. The canals in the experimental groups were irrigated for 3 minutes with 5 ml of 1 mg/ml ethanolic extract of S. persica (n = 15) or BioPure MTAD (n = 15) and then flushed with 2 ml of saline. The presence or absence of smear layer at the coronal and middle portion of each canal were examined under a scanning electron microscope (SEM).

Results

A significant d ifference (p = 0 .004) i n s mear l ayer removal between S. persica and MTAD at the middle third of the canal was observed. MTAD solution was as effective as 17% EDTA in removing the smear layer.

Conclusion

MTAD was significantly more effective in smear layer removal than S. persica solution at the middle third of the canal wall.

Clinical significance

Both tested irrigant solutions have the ability to remove the intracanal smear from primary root dentin following cleaning and shaping of the root canal and could be an alternative to EDTA.

How to cite this article

Balto H, Salama F, Al-Mofareh S, Al-Yahya F. Evaluation of Different Irrigating Solutions on Smear Layer Removal of Primary Root Dentin. J Contemp Dent Pract 2015;16(3):187-191.
Sealing Ability of Root-end Filling Materials
Authors: Borges Alvaro Henrique , Bandéca Matheus Coelho , de Araújo Estrela Cyntia Rodrigues , Amezcua Octávio , Gonzalez Álvaro Cruz , Estrela Carlos
Published: May 2015

Background

The aim of this research was to compare the apical sealing ability of different root-end filling materials (Super EBA®, ProRoot MTA®, thermoplasticized gutta-percha + AHPlus®, thermoplasticized RealSeal®), by means of microbial indicators.

Materials and methods

Thus, 50 human single-rooted teeth were employed, which were shaped until size 50, retro-prepared with ultrasonic tips and assigned to 4 groups, retro-filled with each material or controls. A platform was employed, which was split in two halves: upper chamber—where the microbial suspension containing the biological indicators was introduced (E. faecalis + S. aureus + P. aeruginosa + B. subtilis + C. albicans); and a lower chamber containing the culture medium brain, heart infusion, where 3 mm of the apical region of teeth were kept immersed. Lectures were made daily for 60 days, using the turbidity of the culture medium as indicative of microbial contamination. Statistical analyses were carried out at 5% level of significance.

Results

The results showed microbial leakage at least in some specimens in all of the groups. RealSeal® has more microbial leakage, statistically significant, compared to ProRoot® MTA and SuperEBA®. No significant differences were observed when compared ProRoot® MTA and SuperEBA®. The guttapercha + AH Plus results showed no statistically significant differences when compared with the other groups.

Conclusions

All the tested materials showed microbial leakage. Root-end fillings with Super-EBA or MTA had the lowest bacterial filtration and RealSeal shows highest bacterial filtration.

How to cite this article

Amezcua O, Gonzalez AC, Borges AH, Bandeca MC, de Araújo Estrela CR, Estrela C. Sealing Ability of Root-end Filling Materials. J Contemp Dent Pract 2015;16(3):210-214.
Efficacy of Oral Exfoliative Cytology in Diabetes Mellitus Patients: A Light Microscopic and Confocal Microscopic Study
Authors: Gopal Deepika , Malathi N , Reddy B Thirupathi
Published: May 2015

Aim

Diabetes mellitus (DM) has become a global problem. By monitoring the health status of these individuals, diabetic complications can be prevented. We aimed to analyze alterations in the morphology and cytomorphometry of buccal epithelial cells of type 2 DM patients using oral exfoliative cytology technique and determine its importance in public health screening, diagnosis and monitoring of diabetes mellitus.

Materials and methods

The study was carried out in 100 type 2 DM patients and 30 healthy individuals. Smears were taken from the right buccal mucosa and stained by the Papanicolaou technique. Staining with Acridine orange was carried out to view qualitative changes with confocal laser scanning microscope (LSM-510 Meta). The cytomorphometry was evaluated using IMAGE PRO PLUS 5.5 software with Evolution LC camera. All findings were statistically analyzed.

Results

The results showed that with increase in fasting plasma glucose levels, there is significant increase in nuclear area, decrease in cytoplasmic area, and increase in nuclear cytoplasmic ratio (p < 0.05) when compared to the control group. Various qualitative changes were noted, such as cell degeneration, micronuclei, binucleation, intracytoplasmic inclusion, candida and keratinization.

Conclusion

In the present study, we found significant alterations in the cytomorphometry and cytomorphology of buccal epithelial cells of type 2 DM patients. This study supports and extends the view that these cellular changes can alert the clinician to the possibility of diabetes and aid in monitoring of diabetes throughout the lifetime of the patient.

How to cite this article

Gopal D, Malathi N, Reddy BT. Efficacy of Oral Exfoliative Cytology in Diabetes Mellitus Patients: A Light Microscopic and Confocal Microscopic Study. J Contemp Dent Pract 2015;16(3):215-221.
Removal of an Instrument Fractured by Ultrasound and the Instrument Removal System under Visual Magnification
Authors: Cruz Alvaro , Mercado-Soto Claudia Gabriela , Ceja Israel , Gascón L Gerardo , Cholico Patricia , Palafox-Sánchez Claudia A
Published: May 2015

Aim

The case of a lower molar with apical periodontitis, which had previous root canal treatment and a fractured instrument in the distal root beyond the foramen, is presented.

Background

The simultaneous presence of a foreign body (endodontic instrument or material) in periapical tissues and microorganisms in the root canal, are etiological factors in the formation or maintenance of a periapical lesion, and can lead to failure in endodontic treatment.

Case description

This instrument was removed through the staging platform technique, by using ultrasound and an Instrument removal system (IRS) microtube under microscope visual amplification. All the canals were re-instrumented, irrigated with sodium hypochlorite and passive ultrasonic irrigation, removal of smear layer and intracanal medication with calcium hydroxide for 8 days, after which they were filled. The symptoms disappeared and clinical and radiograph 2-year follow-up shows healing of periapical tissues.

Conclusion

The combined use of visual magnification microscope, ultrasound and the IRS system by staging platform technique, allowed the removal of an endodontic instrument beyond the foramen, which made it possible to apply a conventional disinfection protocol.

Clinical significance

Endodontic re-treatment by conservative approach of complicated cases it is an option with good clinical prognosis, before apical surgery or extraction.

How to cite this article

Cruz A, Mercado-Soto CG, Ceja I, Gascón LG, Cholico P, Palafox-Sánchez CA. Removal of an Instrument Fractured, by Ultrasound and the Instrument Removal System under Visual Magnification. J Contemp Dent Pract 2015;16(3):238-242.
Free amino acids in Antarctic aerosol: potential markers for the evolution and fate of marine aerosol
Authors: Barbaro E. , Zangrando R. , Vecchiato M. , Piazza R. , Cairns W. R. L. , Capodaglio G. , Barbante C. , Gambaro A.
Published: May 2015

Abstract. To investigate the impact of marine aerosols on global climate change it is important to study their chemical composition and size distribution. Amino acids are a component of the organic nitrogen in aerosols and particles containing amino acids have been found to be efficient ice nuclei. The main aim of this study was to investigate the L- and D-free amino acid composition as possible tracers of primary biological production in Antarctic aerosols from three different areas: two continental bases, Mario Zucchelli Station (MZS) on the coast of the Ross Sea, Concordia Station at Dome C on the Antarctic Plateau, and the Southern Ocean near the Antarctic continent. Studying the size distribution of amino acids in aerosols allowed us to characterize this component of the water-soluble organic carbon (WSOC) in marine aerosols near their source and after long-range transport. The presence of only free L-amino acids in our samples is indicative of the prevalence of phytoplanktonic material. Sampling at these three points allowed us to study the reactivity of these compounds during long-range transport. The mean total amino acid concentration detected at MZS was 11 pmol m−3, a higher percentage of amino acids were found in the fine fraction. The aerosol samples collected at Dome C had the lowest amino acid values (0.7 and 0.8 pmol m−3), and the coarse particles were found to have higher concentrations of amino acids compared to the coastal site. The amino acid composition in the aerosol collected at Dome C had also changed compared to the coastal site, suggesting that physical and chemical transformations had occurred during long range transport. During the sampling cruise on the R/V Italica on the Southern Ocean, high concentrations of amino acids were found in the total suspended particles, this we attribute to the presence of intact biological material (as microorganisms or plant material) in the sample.
The impact of volcanic aerosols on stratospheric ozone and the Northern Hemisphere polar vortex: separating radiative from chemical effects under different climate conditions
Authors: Muthers S. , Arfeuille F. , Raible C. C. , Rozanov E.
Published: May 2015

Abstract. After strong volcanic eruptions stratospheric ozone changes are modulated by heterogeneous chemical reactions (HET) and dynamical perturbations related to the radiative heating in the lower stratosphere (RAD). Here, we assess the relative importance of both processes as well as the effect of the resulting ozone changes on the dynamics using ensemble simulations with the atmosphere–ocean–chemistry–climate model (AOCCM) SOCOL-MPIOM forced by eruptions with different strength. The simulations are performed under present day and preindustrial conditions to investigate changes in the response behaviour. The results show that the HET effect is only relevant under present day conditions and causes a pronounced global reduction of column ozone. These ozone changes further lead to a slight weakening of the Northern Hemisphere (NH) polar vortex during mid-winter. Independent from the climate state the RAD mechanism changes the column ozone pattern with negative anomalies in the tropics and positive anomalies in the mid-latitudes. The influence of the climate state on the RAD mechanism significantly differs in the polar latitudes, where an amplified ozone depletion during the winter months is simulated under present day conditions. This is in contrast to the preindustrial state showing a positive column ozone response also in the polar area. The dynamical response of the stratosphere is clearly dominated by the RAD mechanism showing an intensification of the NH polar vortex in winter. Still under present day conditions ozone changes due to the RAD mechanism slightly reduce the response of the polar vortex after the eruption.
An improved method for retrieving nighttime aerosol optical thickness from the VIIRS Day/Night Band
Authors: McHardy T. M. , Zhang J. , Reid J. S. , Miller S. D. , Hyer E. J. , Kuehn R. E.
Published: May 2015

Abstract. Using Visible/Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) data, a method, dubbed the "variance method", is developed for retrieving nighttime aerosol optical thickness (τ) values through the examination of the dispersion of radiance values above an artificial light source. Based on the improvement of a previous algorithm, this updated method derives a semi-quantitative indicator of nighttime τ using artificial light sources. Nighttime τ retrievals from the newly developed method are inter-compared with an interpolated value from late afternoon and early morning ground observations from four AErosol RObotic NETwork (AERONET) sites as well as column-integrated τ from one High Spectral Resolution Lidar (HSRL) site at Huntsville, AL during the NASA Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign, providing full diel coverage. Sensitivity studies are performed to examine the effects of lunar illumination on VIIRS τ retrievals made via the variance method, revealing that lunar contamination may have a smaller impact than previously thought, however the small sample size of this study limits the conclusiveness thus far. VIIRS τ retrievals yield a coefficient of determination (r2) of 0.60 and a root-mean-squared-error (RMSE) of 0.18 when compared against straddling daytime-averaged AERONET τ values. Preliminary results suggest that artificial light sources can be used for estimating regional and global nighttime aerosol distributions in the future.
Salinization alters fluxes of bioreactive elements from streams and soils across land use
Authors: Duan S.-W. , Kaushal S. S.
Published: May 2015

Abstract. There has been increased salinization of fresh water over decades due to the use of road salt deicers, wastewater discharges, human-accelerated weathering, and groundwater irrigation. The effects of increased salinization on biogeochemical cycles in freshwater ecosystems are still not well understood. We investigated potential impacts of increased salinization on fluxes of bioreactive elements from stream sediments and riparian soils to overlying stream water. Two-day incubations of sediments and soils with stream and deionized water across 3 salt levels were conducted at 8 routine monitoring stations at the Baltimore Ecosystem Study Long-Term Ecological Research (LTER) site in the Chesapeake Bay watershed. Ambient stream chemistry was also monitored before and after a snow event coinciding with road salt additions. Results indicated: (1) salinization typically increased sediment releases of labile dissolved organic carbon (DOC), dissolved inorganic carbon (DIC), total dissolved Kjeldahl nitrogen (TKN) (ammonium + ammonia + dissolved organic nitrogen), and sediment transformations of nitrate, (2) salinization generally decreased DOC aromaticity and fluxes of soluble reactive phosphorus (SRP) from both sediments and soils, (3) the effects of increased salinization on sediment releases of DOC and TKN and DOC quality increased with percentage watershed urbanization. The differential responses of riparian soils and sediments to increased salinization were likely due to differences in organic matter amounts and composition. Results of the sediment and soil incubations were used to interpret changes in ambient stream chemistry before and after a snow event. Our results suggest that short-term increases in salinization can cause releases of significant amounts of labile organic carbon and nitrogen from stream substrates and organic transformations of nitrogen and phosphorus. Given that salinization of fresh water will increase in the future, potential impacts on coupled biogeochemical cycles and water quality should be expected.
Parameterization of biogeochemical sediment–water fluxes using in-situ measurements and a steady-state diagenetic model
Authors: Laurent A. , Fennel K. , Wilson R. , Lehrter J. , Devereux R.
Published: May 2015

Abstract. Diagenetic processes are important drivers of water column biogeochemistry in coastal areas. For example, sediment oxygen consumption can be a significant contributor to oxygen depletion in hypoxic systems and sediment–water nutrient fluxes support primary productivity in the overlying water column. Moreover, non-linearities develop between bottom water conditions and sediment–water fluxes due to loss of oxygen-dependent processes in the sediment as oxygen becomes depleted in bottom waters. Yet, sediment–water fluxes of chemical species are often parameterized crudely in coupled physical-biogeochemical models, using simple linear parameterizations that are only poorly constrained by observations. Diagenetic models that represent sediment biogeochemistry are available, but rarely are coupled to water column biogeochemical models because they are computationally expensive. Here, we apply a method that efficiently parameterizes sediment–water fluxes by combining in situ measurements, a steady state diagenetic model and a parameter optimization method. We apply this method to the Louisiana Shelf where high primary production, stimulated by excessive nutrient loads from the Mississippi-Atchafalaya River system, promotes the development of hypoxic bottom waters in summer. The parameterized sediment–water fluxes represent non-linear feedbacks between water column and sediment processes at low bottom water oxygen concentrations, which may persist for long periods (weeks to months) in hypoxic systems such as the Louisiana Shelf. This method can be applied to other systems and is particularly relevant for shallow coastal and estuarine waters where the interaction between sediment and water column is strong and hypoxia is prone to occur due to land-based nutrient loads.