bluuebunny/crossref_metadata_2025 huggingface dataset:
Colorful Nanofibers for Advanced Apparel Application
Authors: Ahmed Farooq , Qureshi Umair Ahmed , Khatri Zeeshan
Published: March 2018

We report herein, the synthesis of colorful nanofibers by electrospinning and dyeing with various class of dyestuff. Results revealed that dyes impart better color yield with the acceptable colorimetric values, color yield and color fastness. Morphology of nanofibers showed smooth surface of the dyed nanofibers under SEM. Cellulose nanofibers in particular, were prepared using precursor cellulose acetate and then converted into cellulose under alkaline treatment. Results revealed that dyes impart better color yield with the adequate color yield (KS) and color fastness. Morphology of nanofibers showed smooth nanofibers after dyeing under SEM. Based results obtained, the colorful nanofiber can be a better choice for advance apparel applications.
Adsorption of Methylene Blue (MB) Dye in Wastewater by Electrospun Polysulfone (PSF)/Organo-Montmorillonite (O-MMT) Nanostructured Membrane
Authors: Aquino Ruth R. , Tolentino Marvin S. , Crisogono Bianca Mae Z. , Salvacion Sarah Katrina V.
Published: March 2018

In this study, organo-montmorillonite was utilized as an additive for the fabrication of the nanostructured membrane via electrospinning process.The purpose of this study is to investigate the performance of 95% PSF and 5% O-MMT blend in terms of its adsorption capacity towards MB dye in wastewater and comparing it to pure PSF membranes. Pure PSF and 5% O-MMT blend were immersed in the simulated wastewater at different time intervals (1, 5, 12, 24 and 48 hours), and the change in MB dye concentration was observed by UV-Vis absorbance reading. To determine the mechanism of adsorption, the data obtained were subjected to pseudo-first order and pseudo-second order kinetic models, and were fitted to Langmuir, Freundlich and Temkin adsorption isotherms to determine the adsorption equilibrium data. The results show that the adsorption efficiency was improved by 5.32%.
Synthesis, Short-Range Structure and Hydration Processes of Oxyhalides Ba2InO3X (X = F, Cl, Br) with Ruddlesden-Popper Structure
Authors: Tarasova Nataliia , Animitsa Irina
Published: March 2018

The oxyhalides Ba2InO3F, Ba2InO3Cl, and Ba2InO3Br were synthesized using the solid state method. It was found that the increasing of halide ion radius leads to the increase of lattice parameters and also caused to redistribution of indium-oxygen bond lengths. The possibility of water uptake was proved by thermogravimetry measurements. The presence of different forms of oxygen-hydrogen groups in the structure of hydrated oxyhalides was indicated by infrared spectroscopy.
One-Step FSP Synthesis of Nanocrystalline Fe/Al2O3 and Fe-Ce/Al2O3 Catalyst for CO2 Hydrogenation Reaction
Authors: Piriyasurawong Kanyarat , Piticharoenphun Sunthon , Mekasuwandumrong Okorn
Published: March 2018

Nanocrystalline Fe/Al2O3 and Fe-Ce/Al2O3 catalysts doped with various amounts of cerium were prepared using the one-step flame spray pyrolysis (FSP) technique. The characterization of the catalysts was measured by several methods such as X-ray diffraction, nitrogen physisorption and hydrogen temperature programmed reduction (H2-TPR) techniques. The results revealed that the FSP-made catalyst exhibited the characteristic pattern of FeAl2O4 phase without any phases of aluminum or iron oxide. In addition, cerium (Ce) dopant did not alter crystal structure at low content. However, 7 wt% content of cerium dopant resulted in the formation of ceria (CeO) and iron oxide (Fe2O3) phase. The catalytic performance of the FSP-made catalyst was tested in carbon dioxide hydrogenation for selective production of long chain hydrocarbon, and was compared to conventional impregnation-made catalysts. In the comparison, the FSP-made catalyst exhibited lower catalytic activity but possessed a higher long chain hydrocarbon selectivity. After doping with Ce, the catalytic activity was improved while the hydrocarbon selectivity was decreased and shifted to the short chain hydrocarbon product. In the case of conventional-made catalysts, the activity remained unchanged but the hydrocarbon selectivity was decreased. Among all catalysts, the FSP-made Fe-Ce/Al2O3 catalyst with 3% Ce-promoted catalyst exhibited the best performance in terms of selectivity to long chain hydrocarbon.
Encapsulation of Bioactive Compounds (Monocaprin and Monolaurin) into Polymeric Nanoparticles
Authors: Kaewmanee Paramaporn Chiewpattanakul , Wongsatayanon Benjamas , Durand Alain
Published: March 2018

The dextran-covered poly (lactic acid) (PLA) polymeric nanoparticles were prepared by a nanoprecipitation process for the encapsulation of monocaprin (MC) or monolaurin (ML). The concentration of PLA/MC or ML was varied to evaluate the best condition for preparation. The miscibility of various PLA/MC or ML blends was studied using differential scanning calorimetry. The result showed that at concentrations of 50/50 wt/wt, the PLA/ML blend was partly miscible and the nanoparticle suspension produced large amounts of macroscopic aggregates after nanoprecipitation. Conversely, the miscibility of PLA/MC blends progressively increased with increasing amounts of PLA. Therefore, the best concentration to encapsulate the MC was the PLA/MC 90/10 (wt/wt), according to the miscibility results.
High Cycle Fatigue Properties of Multi-Directionally Forged Commercial Purity Grade 2 Ti Plate
Authors: Ilhamdi Ilhamdi , Kakiuchi Toshifumi , Miura Hiromi , Uematsu Yoshihiko
Published: March 2018

Tension-tension fatigue tests were conducted using ultrafine-grained commercially pure Titanium (Ti) plates fabricated by multi-directional forging (MDFing). The MDFed pure Ti plates with the thickness of 1 mm were developed aiming at dental implant application. The fatigue properties of MDFed pure Ti plates were superior to those of the conventional rolled pure Ti plates. The higher fatigue strengths in MDFed plates could be attributed to the much finer grains evolved by MDFing. Fatigue crack initiated from specimen surface, when number of cycles to failure was shorter than 106 cycles. In the high cycle fatigue (HCF) region, however, subsurface crack initiation with typical fish-eye feature was recognized in the MDFed pure Ti plate in spite of the thin thickness. Fractographic analyses revealed that no inclusion existed at the center of fish-eye. The subsurface crack initiation mechanism could be related to the inhomogeneity of microstructure with some coarse grains in the inner part of the plate.
Effect of Thermal Oxidation and Carbon Concentrations on Co-Cr-Mo Alloy in Enhanced Corrosion Protection
Authors: Mas-Ayu H. , Daud Rosdi , Shah Arman , Hazwan H.M. , Tomadi Siti Haryani , Salwani Mohd Salleh
Published: March 2018

Surface modification of metallic implants is often required to facilitate positive interaction between the implant and the surrounding hard tissue. In the present study, an oxide layer (Cr2O3) was successfully created on a Co-Cr-Mo alloys substrate by using thermal oxidation technique in atmospheric condition. The effect of different carbon content (0.03% and 0.24%) of oxidized Co-Cr-Mo alloys was investigated in terms of its corrosion behavior using electrochemical impedance spectroscopy techniques that immersed in simulated body fluid. The corrosion tests were repeated for five times for each of sample condition. The results demonstrated that thermal oxidation and carbon content have correlation in influencing the corrosion performance in Co-Cr-Mo alloys. A high carbon content sample generates a lower corrosion-rate compared to low carbon content sample even though all samples were treated at similar oxidation temperature and time duration. Observation also showed that less diffusion of cobalt released in high carbon sample which is believed has effects in creating the uniformity and dense oxide layer without any presence of microcracks and delamination. This phenomenon can be concluded that carbon content in Co-Cr-Mo alloy have influenced in controlling the reaction of metal elements during thermal oxidation which is beneficial in formation of oxide layer. The uniformity and compact oxide layer substantially have enhanced the corrosion resistance of high carbon Co-Cr-Mo alloy.
An Investigation into the Potential Use of Calcium Carbonate Nanoparticles in Mine Backfill
Authors: Hefni Mohammed A. , Hassani Ferri P. , Kermani Mehrdad F.
Published: March 2018

This study is part of large and ongoing investigation into the potential use of calcium carbonate nanoparticles (NCaCO3) to improve the mechanical and physical properties of mine backfill. The investigation was conducted in two phases. In phase I, gold tailings were used to prepare backfill sample using Portland cement (PC) as the binding agent under various NCaCO3 and superplasticizer (SP) dosages. In phase II, fine silica sand was used to minimize the reactive nature of tailings, which can adversely affect uniaxial compressive strength (UCS). Samples in this phase were prepared under various NCaCO3 dosages using slag:PC weight ratios of 80:20 as the binding agent. Select samples from phase II were subjected to Mercury Intrusion Porosimetry (MIP) to compare microstructural properties before and after addition of NCaCO3. Phase I results showed that the UCS of samples containing NCaCO3 was low, even when SP was used to improve particle dispersion. Phase II samples exhibited up to 9.5% higher UCS after 28 days of curing at a NCaCO3 dosage of 6% by weight of binder. MIP results showed that samples containing NCaCO3 were less porous than the corresponding controlled silica sand backfill samples, which in turn influenced the UCS results.
Comparison of Morphology and Mechanical Properties of Polyoxymethylene/Cellulose and Poly(Lactic Acid)/Cellulose Composites
Authors: Wacharawichanant Sirirat , Wimonsupakit Nisarat , Kuhaudomlap Sasithorn
Published: March 2018

The objective of this study is to fabricate the polyoxymethylene (POM)/microcrystalline cellulose (MCC) and poly(lactic acid) (PLA)/MCC composites, and to compare the effect of MCC on the morphology and mechanical properties of POM and PLA. The polymer composites were prepared by melt mixing in an internal mixer and molded by compression molding. The MCC concentrations were 1, 3, 5, 7, 10, 15 and 10% by weight. From scanning electron microscopy study observes the fracture surface of POM and PLA composites is much rough and the roughness increases with increasing MCC content. This observation indicates MCC induces the ductile fracture characteristic of POM and PLA. The addition of MCC can improve the impact strength of PLA composite and improve Young’s modulus of both POM and PLA composites. While the tensile strength and strain at break decrease after adding MCC. In summary, MCC can enhance the morphology and mechanical properties of PLA composites is better than POM composites.
Characterization of Non-Metallic Inclusions in API Steel Grades Using Automated Energy Dispersive X-Ray
Authors: Al-Gahtani Masoud , Pillai Sunilkumar , Al-Raddadi Ahmad
Published: March 2018

Non-metallic inclusions in API steel grades deteriorate steels’ mechanical properties and their resistance to hydrogen induced cracking. The formation and evolution of inclusion during liquid steel processing was investigated by analyzing samples taken from different stages of the steel making process in API X52 and X60 steel grades. Scanning electron microscope (SEM) with automated feature EDX analyzer (INCAF 250) was used to identify each inclusion in terms of its size, area and composition. It was found that non-metallic inclusions in API X52 and X60 grades from steelmaking and casting samples were mainly Al2O3, Ca–Al and Ca-Mg-Al. In this work changes in inclusion composition, size and area fraction from ladle processing to casting were mapped and this information was used to improve steel cleanness and product quality.
Numerical and Experimental Investigation on Corrugation Geometry for Metallic Tubes under Lateral Loading
Authors: Eyvazian Arameh , Mozafari Hozhabr , Tarlochan Faris , Hamouda Abdel Magid S.
Published: March 2018

Energy absorption devices are being used to protect structures from severe damages and reduce injury to occupants during accidents. The integrated characteristics of crash absorption devices can be classified as high energy absorption capacity, light-weight, and cost-effective. One of the thin-walled structures which has drawn the attention of scientists is corrugated tube structure. In this paper, the effect of corrugation geometry on the crushing parameters of an aluminum corrugated tube is investigated. In this regard, different elliptical corrugation shapes were deemed and the compression response was numerically evaluated under lateral quasi-static loading. Finally, the crashworthiness parameters were extracted and compared to determine the influence of corrugation shape on the crashworthy response. Our results showed that using vertical elliptical corrugation decrease the densification point. Moreover, there is a gradual enhancement of mean crushing load by moving from the horizontal elliptical corrugations to the vertical ones. Also, by modifying of corrugation shape, the stress variation pattern changes, significantly.
Evaluation of Thermal History and Defect in Friction Stir Processing of As-Cast Magnesium AZ91
Authors: Esmaeili Ali , Hamouda Abdel Magid S.
Published: March 2018

Friction stir processing (FSP) is a thermos-mechanical process for modifying the microstructural and material properties of metals. FSP also can be used for mechanical alloying and producing metal matrix composites. Due to creation of longitudinal cracks and tunneling cavities throughout the processing path, FSP of AZ91 is difficult and also sensitive to processing temperature. In this study, the effect of processing parameters such as the traverse and rotational speeds and the dimension of the tool pin on the temperature history experienced by material were investigated. Additionally, a minimum temperature required to produce a defect-free specimen was presented.
The Influence of the Tablet Height and Plunger Pressing Velocity on the Final Porosity of Die Casting
Authors: Gaspar Stefan , Pasko Jan , Knezo Dusan
Published: March 2018

With a pressure die casting process, one of the important factors affecting the quality of castings represented by porosity is plunger pressing velocity determines the regime die cavity filling and correct determination of dose mass of a molten metal required for one casting cycle. The mass is given by a total of the net mass of a casting, overflows, a gate system and a metal rest inside a filling chamber (the tablet height). As a rule, the tablet height represents the largest mass ratio regarding the waste metal. A correct determination of the tablet height is important from both economical and qualitative aspect of a pressure die casting process.
Microwave Absorbing Property of Thin Coating in the Broadband Low-Frequency Range
Authors: Chen Le , Gu Zhao Zhan , Zhang Ming Xue
Published: March 2018

Coatings with flake carbonyl-iron powder as absorber and polyurethane resin as matrix were prepared. The complex permittivity, complex permeability and microwave-absorbing properties were investigated in the frequency range of 2–18 GHz. Both the complex permittivity and permeability of the flaky carbonyl-iron were increased compared to the spherical powders. The minimum reflection loss decreased and the matching frequency shifted to the lower frequency region with increase in the coating thickness. The band width can reach nearly 16GHz as the RL was below than-4 dB with thickness only 1.4 mm. The minimum reflection loss value of-14.5 dB was obtained at 3.56 GHz for the 1.6mm coatings with 89 wt% carbonyl-iron powders. These results showed that the coatings were favorable for the broadband low-frequency microwave absorption with a small thickness.
Its Optical Property and Characterization of Silver Antimony Sulfide Nanostructured Clusters Synthesized Using a Facile Wet Chemical Route
Authors: Saksornchai Eksuree , Kavinchan Jutarat
Published: March 2018

Cubic phase of silver antimony sulfide (AgSbS2) nanostructures were successfully synthesized from silver nitrate (AgNO3), antimony acetate (CH3CO2)3Sb, and sodiumthiosulphate pentahydrate (Na2S2O3.5H2O) in propylene glycol (PG) without using any surfactants or splitting agents by a facile wet chemical route at 160 OC for 30 min. The XRD, SEM and TEM reveal AgSbS2 nanostructures forming the clusters. Due to the UV-visible absorption shows its direct band gap, is 1.80 eV, AgSbS2 is found to be the excellent material for the solar energy converters. And the possible formation of AgSbS2 nanostructured cluster was also discussed.
Strengthening Mechanism of Al2O3 Ceramic-Lined Composite Steel Pipe Prepared by the SHS Gravitational Separation Process
Authors: Hou Xing Hui , Yu Jing Kun
Published: March 2018

The Al2O3 ceramic-lined composite steel pipes were produced by the SHS gravitational separation process (SHS-GS process) from Al, Fe2O3 and Cr2O3 as the raw materials within different reaction systems. The phase, composition, micro-structure and properties of ceramic coatings were investigated to discuss the strengthening mechanism of the composite steel pipe. The results showed that the phase composition of Al-Fe2O3-Cr2O3 reaction system could be Al2O3 and Fe-Cr alloy compared with the Al2O3-Fe-FeAl2O4 phases of Al-Fe2O3 reaction system, which led to the increase of strength and hardness of ceramic coating. Because the Fe-Cr alloy was formed instead of Fe element, and the addition of Cr2O3 reduced the production of erodible FeAl2O4. The transition structure consisted of ceramic coating-transition layer-steel pipe was formed, and in its direction the Al and O element contents decreased, the metallic Fe and Cr increased. Therefore, the transitional changes of all the element contents could decrease the stress difference between the layers, and increase the bonding strength of the composite steel pipe.
Morphology Induced Effect on the Electrochemical Activity of Cobaltous Oxide Nanostructures in Potassium Hydroxide and Phosphoric Acid Media
Authors: Untalasco John Lemuel G. , Mariscal Abdul Rahman , Marquez Menandro C.
Published: March 2018

The morphology of cobalt oxide / cobaltous oxide (Co3O4) nanostructures was controlled using different seed layer concentrations and deposition time. Co3O4 nanostructures were deposited on ITO glass synthesized using two step solution route. The morphological evolution of the Co3O4 nanostructures has been investigated using scanning electron microscopy (SEM). This has been correlated to the electrochemical activity of the material using cyclic voltammetry (CV) in a potassium hydroxide (KOH) and phosphoric acid (H3PO4) media. Other characterization technique such as x-ray diffraction analysis (XRD) was used to verify the crystal structures of the Co3O4 nanostructures. The Co3O4 nanostructures revealed pronounced redox peaks in a 1M KOH electrolyte which proved its high electrochemical activity. Also the redox peaks increases with the increase in scan rate which demonstrated good reversibility of a fast charge-discharge response. Varying CV curves have been observed in a 1M H3PO4 electrolyte which denotes the instability of Co3O4. The change in the morphology of Co3O4 certainly affects the electrochemical property of the Co3O4. This leads to an advance study for its promising electrochemical applications for a cleaner energy.
Different Selected Mechanisms Attenuated the Inhibitory Interaction of KIR2DL1 with C2+ HLA-C in Two Indigenous Human Populations in Southern Africa
Authors: Nemat-Gorgani Neda , Hilton Hugo G. , Henn Brenna M. , Lin Meng , Gignoux Christopher R. , Myrick Justin W. , Werely Cedric J. , Granka Julie M. , Möller Marlo , Hoal Eileen G. , Yawata Makoto , Yawata Nobuyo , Boelen Lies , Asquith Becca , Parham Peter , Norman Paul J.
Published: March 2018

The functions of human NK cells in defense against pathogens and placental development during reproduction are modulated by interactions of killer cell Ig-like receptors (KIRs) with HLA-A, -B and -C class I ligands. Both receptors and ligands are highly polymorphic and exhibit extensive differences between human populations. Indigenous to southern Africa are the KhoeSan, the most ancient group of modern human populations, who have highest genomic diversity worldwide. We studied two KhoeSan populations, the Nama pastoralists and the ≠Khomani San hunter-gatherers. Comprehensive next-generation sequence analysis of HLA-A, -B, and -C and all KIR genes identified 248 different KIR and 137 HLA class I, which assort into ∼200 haplotypes for each gene family. All 74 Nama and 78 ≠Khomani San studied have different genotypes. Numerous novel KIR alleles were identified, including three arising by intergenic recombination. On average, KhoeSan individuals have seven to eight pairs of interacting KIR and HLA class I ligands, the highest diversity and divergence of polymorphic NK cell receptors and ligands observed to date. In this context of high genetic diversity, both the Nama and the ≠Khomani San have an unusually conserved, centromeric KIR haplotype that has arisen to high frequency and is different in the two KhoeSan populations. Distinguishing these haplotypes are independent mutations in KIR2DL1, which both prevent KIR2DL1 from functioning as an inhibitory receptor for C2+ HLA-C. The relatively high frequency of C2+ HLA-C in the Nama and the ≠Khomani San appears to have led to natural selection against strong inhibitory C2-specific KIR.
Flooding and poverty: Two interrelated social problems impacting rural development in Tsholotsho district of Matabeleland North province in Zimbabwe
Authors: Dube Ernest , Mtapuri Oliver , Matunhu Jephias
Published: March 2018

Flooding and poverty are the two social problems that have coexisted within the rural communities of Tsholotsho district. As a result, both problems have negatively affected and disrupted the everyday pattern of lives of people living in the district. This study sought to highlight how the two problems combine to impact human societies. The objectives that the study sought to fulfil were to establish the impact of flooding on the development of rural communities, to analyse how poverty manifests itself in rural communities, to analyse the relationship that exists between flooding and poverty and to suggest ways for dealing with the two problems. A qualitative research approach, using interviews and observations, was used to gather data from the research participants. The study findings were that flooding impeded development through shifting of human populations, destruction of crops, shelter and livestock. Floods also affected human capital through causing injuries to members of the community. Poverty manifested itself in three ways – as a development barrier, a vulnerability amplifier and a non-discriminatory agent. The study further found that a strong relationship exists between flooding and poverty because of the fact that flooding causes or worsens poverty, whereas poverty increases flood vulnerability. The study concluded that the poor need government assistance to reconstruct shelter destroyed by floods. Furthermore, programs aimed at improving livelihoods of the poor are an indispensable imperative. This study informs policymakers and offers a methodological significance to development and disaster practitioners. It also adds to the body of literature on flooding and poverty.
Evaluation of Flexural Strength of Polymethyl Methacrylate modified with Silver Colloidal Nanoparticles subjected to Two Different Curing Cycles: An in vitro Study
Authors: Ranganath LM , Gaikwad Ajay , Jain Saket K , Pal Kapil S
Published: March 2018

Aim

Silver colloidal nanoparticles have been incorporated into acrylic resins to induce antimicrobial properties. However, as additives, they can influence the mechanical properties of the final product. Mechanical properties are also dependent on different curing cycles. The aim of this study was to evaluate flexural strength of a denture base resin incorporated with different concentrations of silver colloidal nanoparticles subjected to two different curing cycles.

Materials and methods

Lucitone 199 denture base resin was used into which silver colloidal nanoparticles were incorporated at 0.5 and 5% by polymer mass. Specimens devoid of nanoparticles were used as controls. A total of 60 specimens were fabricated and divided into two groups. Each group was divided into three subgroups consisting of 10 specimens each. The specimens were fabricated according to American Dental Association (ADA) specification No. 12 and tested for flexural strength using universal testing machine.

Results

Silver colloidal nanoparticle incorporation at 0.5% concentration increased the mean flexural strength in both curing cycles by 7.5 and 4.4%, respectively, when compared with the control group.

Conclusion

The study suggested that the mean flexural strength value of 0.5% silver colloidal nanoparticles in denture base resin was above the value of the control group both in short and long curing cycles, which makes it clinically suitable as a denture base material. However, at 5% concentration, the statistically significant amount of decrease in flexural strength compared with the value of control group both in short and long curing cycles gives it a questionable prognosis.

Clinical significance

The specimens incorporated with the antimicrobial agent 0.5% silver colloidal nanoparticles and processed by long curing cycles showed significant increase in its flexural strength compared with the control group, which makes it clinically suitable as a denture base material.

How to cite this article

Munikamaiah RL, Jain SK, Pal KS, Gaikwad A. Evaluation of Flexural Strength of Polymethyl Methacrylate modified with Silver Colloidal Nanoparticles subjected to Two Different Curing Cycles: An in vitro Study. J Contemp Dent Pract 2018;19(3):262-268.
Comparison between Fluoride and Nano-hydroxyapatite in Remineralizing Initial Enamel Lesion: An in vitro Study
Authors: Daas Issa , Badr Sherine , Osman Essam
Published: March 2018

Aim

The aim of this study was to compare the effectiveness of nano-hydroxyapatite (nano-HAP) paste and fluoride varnish in remineralizing initial enamel lesion in young permanent teeth and their ability to resist secondary caries under dynamic pH cycling quantitatively and qualitatively.

Materials and methods

Initial caries-like lesions were artificially developed on 45 specimens. Specimens were divided into three groups: (1) Control (without treatment), (2) fluoride varnish (3M ESPE), and (3) nano-HAP paste (Desensibilize Nano P). The nano-HAP paste was applied twice separated by one pH cycle, and the varnish was applied only once followed by 7 days of pH cycling. All specimens were examined using DIAGNOdent® pen (KaVo, Germany), and a representative specimen was randomly selected from each group for qualitative evaluation using scanning electron microscope (SEM) at four stages: Baseline, after lesion formation, immediately after remineralization, and after pH cycling. Data were statistically analyzed with Statistical Package for the Social Sciences (SPSS), version 20.

Results

The degree of demineralization was significantly elevated in control group; however, no significant difference was found between fluoride varnish group and nano-HAP paste group (p < 0.001).

Conclusion

Nano-HAP paste showed promising long-term protective effect in terms of surface depositions and maintaining a smooth surface compared with fluoride varnish.

Clinical significance

Based on the findings of this study, nano-HAP paste might be recommended as alternative remineralizing agent with lower fluoride concentration than fluoride varnish that could be beneficial for children, pregnant females, and those who are at high risk of dental fluorosis.

How to cite this article

Daas I, Badr S, Osman E. Comparison between Fluoride and Nano-hydroxyapatite in Remineralizing Initial Enamel Lesion: An in vitro Study. J Contemp Dent Pract 2018;19(3):306-312.
Utilizing the GentleWave® System for Debridement of Undetected Apical Anatomy
Authors: Ford Michael W
Published: March 2018

Aim and background

Debriding and disinfecting complex anatomies within the root canal system pose a major challenge during root canal therapy. Even with current chemomechanical techniques, debris and bacterial remnants are commonly left behind, which are generally believed to increase the risk of endodontic failure. This case details the use of a new technique to debride complex apical anatomy in a maxillary molar.

Case report

A 48-year-old female presented to the clinic with a chief complaint of increasing pain in her tooth. Clinical examination of the right first maxillary molar (#3) revealed moderate sensitivity to percussion and mild sensitivity to palpation. A pulpal diagnosis of symptomatic irreversible pulpitis and a periapical diagnosis of symptomatic apical periodontitis were made. Mechanical instrumentation was performed using rotary file size #25/.04 for the mesiobuccal and distobuccal canals and size #25/.06 for the palatal canal to create a fluid path and enable obturation of the root canal system following the GentleWave®Procedure. The GentleWave Procedure was completed using Multisonic Ultracleaning™ for complete debridement and disinfection of the root canal system. The tooth was obturated using a warm vertical continuous wave obturation technique. Postoperative radiographs revealed complex anatomy within the apical third that was undetected both during pre-operative radiography and mechanical instrumentation. The palatal canal exhibited a complex apical delta with multiple points of exit, and the mesiobuccal canal revealed an undetected lateral canal within the apical third that had a separate and distinct egress.

Conclusion and clinical significance

It is important for the clinician to debride and disinfect complex anatomy within the root canal system to reduce the risk of endodontic failure. This case report highlights the clinical significance of utilizing the GentleWave Procedure for detecting complex apical anatomy during endodontic therapy.

How to cite this article

Ford MW. Utilizing the GentleWave®System for Debridement of Undetected Apical Anatomy. J Contemp Dent Pract 2018;19(3):345-351.
Report of a large depletion in the ozone layer over southern Brazil and Uruguay by using multi-instrumental data
Authors: Bresciani Caroline , Bittencourt Gabriela Dornelles , Bageston José Valentin , Pinheiro Damaris Kirsch , Schuch Nelson Jorge , Bencherif Hassan , Leme Neusa Paes , Peres Lucas Vaz
Published: March 2018

Abstract. Ozone is one of the chemical compounds that form part of the atmosphere. It
plays a key role in the stratosphere where the “ozone layer” is located and
absorbs large amounts of ultraviolet radiation. However, during austral
spring (August–November), there is a massive destruction of the ozone layer,
which is known as the “Antarctic ozone hole”. This phenomenon decreases
ozone concentration in that region, which may affect other regions in
addition to the polar one. This anomaly may also reach mid-latitudes; hence,
it is called the “secondary effect of the Antarctic ozone hole”. Therefore,
this study aims to identify the passage of an ozone secondary effect (OSE)
event in the region of the city of Santa Maria – RS (29.68∘ S,
53.80∘ W) by means of a multi-instrumental analysis using the
satellites TIMED/SABER, AURA/MLS, and OMI-ERS. Measurements were made in
São Martinho da Serra/RS – Brazil (29.53∘ S, 53.85∘ W)
using a sounding balloon and a Brewer Spectrophotometer. In addition, the
present study aims to describe and analyse the influence that this
stratospheric ozone reduction has on temperatures presented by these
instruments, including data collected through the radio occultation
technique. The event was first identified by the AURA/MLS satellite on
19 October 2016 over Uruguay. This reduction in ozone concentration was found
by comparing the climatology for the years 1996–1998 for the state of Rio
Grande do Sul, which is close to Uruguay. This event was already observed in
Santa Maria/RS-Brazil on 20 October 2016 as presented by the OMI-ERS
satellite and the Brewer Spectrophotometer. Moreover, a significant decrease
was reported by the TIMED/SABER satellite in Uruguay. On 21 October, the poor
ozone air mass was still over the region of interest, according to the
OMI-ERS satellite, data from the sounding balloon launched in Santa
Maria/RS-Brazil, and measurements made by the AURA/MLS satellite.
Furthermore, the influence of ozone on the stratosphere temperature was
observed during this period. Despite a continuous decrease detected in
height, the temperature should have followed an increasing pattern in the
stratospheric layer. Finally, the TIMED/SABER and OMI-ERS satellites showed
that on 23 October, the air mass with low ozone concentration was moving
away, and its layer, as well as the temperature, in the stratosphere was
re-established. Keywords. Atmospheric composition and structure (middle atmosphere – composition and chemistry; instruments and techniques)
Ages and transit times as important diagnostics of model performance for predicting carbon dynamics in terrestrial vegetation models
Authors: Ceballos-Núñez Verónika , Richardson Andrew D. , Sierra Carlos A.
Published: March 2018

Abstract. The global carbon cycle is strongly controlled by the source/sink strength of vegetation as well as the capacity of terrestrial ecosystems to retain this carbon. These dynamics, as well as processes such as the mixing of old and newly fixed carbon, have been studied using ecosystem models, but different assumptions regarding the carbon allocation strategies and other model structures may result in highly divergent model predictions. We assessed the influence of three different carbon allocation schemes on the C cycling in vegetation. First, we described each model with a set of ordinary differential equations. Second, we used published measurements of ecosystem C compartments from the Harvard Forest Environmental Measurement Site to find suitable parameters for the different model structures. And third, we calculated C stocks, release fluxes, radiocarbon values (based on the bomb spike), ages, and transit times. We obtained model simulations in accordance with the available data, but the time series of C in foliage and wood need to be complemented with other ecosystem compartments in order to reduce the high parameter collinearity that we observed, and reduce model equifinality. Although the simulated C stocks in ecosystem compartments were similar, the different model structures resulted in very different predictions of age and transit time distributions. In particular, the inclusion of two storage compartments resulted in the prediction of a system mean age that was 12–20 years older than in the models with one or no storage compartments. The age of carbon in the wood compartment of this model was also distributed towards older ages, whereas fast cycling compartments had an age distribution that did not exceed 5 years. As expected, models with C distributed towards older ages also had longer transit times. These results suggest that ages and transit times, which can be indirectly measured using isotope tracers, serve as important diagnostics of model structure and could largely help to reduce uncertainties in model predictions. Furthermore, by considering age and transit times of C in vegetation compartments as distributions, not only their mean values, we obtain additional insights into the temporal dynamics of carbon use, storage, and allocation to plant parts, which not only depends on the rate at which this C is transferred in and out of the compartments but also on the stochastic nature of the process itself.
Palaeoclimate significance of speleothems in crystalline rocks: a test case from the Late Glacial and early Holocene (Vinschgau, northern Italy)
Authors: Koltai Gabriella , Cheng Hai , Spötl Christoph
Published: March 2018

Abstract. Partly coeval flowstones formed in fractured gneiss and schist were studied
to test the palaeoclimate significance of this new type of speleothem archive
on a decadal-to-millennial timescale. The samples encompass a few hundred to
a few thousand years of the Late Glacial and the early Holocene. The
speleothem fabric is primarily comprised of columnar fascicular optic calcite
and acicular aragonite, both indicative of elevated Mg ∕ Ca ratios in the
groundwater. Stable isotopes suggest that aragonite is more prone to
disequilibrium isotope fractionation driven by evaporation and prior
calcite/aragonite precipitation than calcite. Changes in mineralogy are
therefore attributed to these two internal fracture processes rather than to
palaeoclimate. Flowstones formed in the same fracture show similar
δ18O changes on centennial scales, which broadly correspond to
regional lacustrine δ18O records, suggesting that such
speleothems may provide an opportunity to investigate past climate conditions
in non-karstic areas. The shortness of overlapping periods in flowstone
growth and the complexity of in-aquifer processes, however, render the
establishment of a robust stacked δ18O record challenging.
Nitrogen attenuation, dilution and recycling at the groundwater
– surface water interface of a subtropical estuary
inferred from the stable isotope composition of nitrate and
water
Authors: Lamontagne Sébastien , Cosme Frédéric , Minard Andrew , Holloway Andrew
Published: March 2018

Abstract. Estuarine environments have a dynamic groundwater – surface water interface driven by terrestrial groundwater discharge, tidal cycles, waves and other processes. This interface also corresponds to an active biogeochemical environment. An assessment of discharging groundwater with elevated (>300 mg N L−1) NH4+ and NO3− concentrations at such an interface located in a subtropical estuary indicated that 80 % of the N was attenuated, one of the highest N removal rates (>100 mmol m−2 day−1) measured for intertidal sediments. The remaining N was also diluted by a factor of two or more by mixing before being discharged to the estuary. Most of the mixing occurred in a hyporheic zone in the upper 50 cm of the riverbed. However, groundwater entering this zone was already partially mixed (12–60 %) with surface water via a tidal circulation cell. Below the hyporheic zone (50–125 cm below the riverbed), NO3− concentrations declined slightly faster than NH4+ concentrations and δ15NNO3) and δ18ONO3 gradually increased, suggesting a co-occurrence of anammox and denitrification. In the hyporheic zone, δ15NNO3 continued to become enriched (consistent with either denitrification or anammox) but δ18ONO3 became more depleted (indicating some nitrification). The discrepancy between δ15NNO3 (23–35 ‰) and δ18ONO3 (1.2–8.2 ‰) in all porewater samples indicated that the original synthetic nitrate pool (δ15N ~ 0 ‰; δ18O ~ 18–20 ‰) had turned-over during transport in the aquifer before reaching the riverbed. Whilst porewater NO3− was more δ18O depleted than its synthetic source, porewater δ18OH2O) (−3.2 to −1.8 ‰) was enriched by 1–4 ‰ relative to rainfall-derived groundwater mixed with seawater. Isotopic fractionation from H2O uptake during the N cycle and H2O production during synthetic NO3− reduction are the probable causes for this δ18OH2O enrichment.
Extreme wildfire events are linked to global-change-type droughts in the northern Mediterranean
Authors: Ruffault Julien , Curt Thomas , Martin-StPaul Nicolas K. , Moron Vincent , Trigo Ricardo M.
Published: March 2018

Abstract. Increasing drought conditions under global warming are expected to alter the
frequency and distribution of large and high-intensity wildfires. However,
our understanding of the impact of increasing drought on extreme wildfires
events remains incomplete. Here, we analyzed the weather conditions
associated with the extreme wildfires events that occurred in Mediterranean
France during the exceptionally dry summers of 2003 and 2016. We identified
that these fires were related to two distinct shifts in the fire
weather space towards fire weather conditions that had not been explored before and
resulting from specific interactions between different types of drought and
different fire weather types. In 2016, a long-lasting “press drought”
intensified wind-driven fires. In 2003, a “hot drought” combining a
heat wave with a press drought intensified heat-induced fires. Our findings
highlight that increasing drought conditions projected by climate change
scenarios might affect the dryness of fuel compartments and lead to a higher
frequency of extremes wildfires events.
Open for Competition: Domesticates, Parasitic Domesticoids and the Agricultural Niche
Authors: Fuller Dorian Q. , Stevens Chris J.
Published: March 2018

This paper explores the relationship of weeds and crop parasites in the domestication of crop-plants within the Old World, drawing predominately on China and the Near East. This relationship is explored using the concept of niche construction in which the act of cultivation sets about chains of feedback in which the ecological worlds of plants and humans became increasingly intertwined resulting in ever increasing spheres of interdependence. Into this domestication entanglement a number of peripheral organisms (termed parasitic domesticoids) were drawn, from the weeds which came to inhabit arable fields, to the insect pests and rodents that came to settle in the grain stores of the first farmers. The evolution and spread of these organisms is then outlined against that of the crop itself.
Applying the Theory of Planned Behaviour (TPB) in Saving Behaviour of Pomak Households
Authors: Satsios Nikolaos , Hadjidakis Spyros
Published: March 2018

The following study uses the Ajzen’s Theory of Planned Behaviour as a theoretical framework with the purpose of extending a model which examines the saving behaviour of the Pomak households. The aim of this research is to identify factors that influence the saving behaviour of Pomak households in Greece. For the collection of data from households, a structured questionnaire was designed and distributed. The data of the study were obtained from a survey applied in 600 households in the prefectures of Xanthi, Rodopi and Evros. A path analysis was applied in order to confirm the proposed model and the results of the hypothesis tested. Findings show that attitude, subjective norm and perceived behavioural control have a direct positive effect on intention towards saving and final saving behaviour. The understanding of the Pomaks’ saving behaviour can have a significant contribution in the pursuit of a healthy household’s financial life.
A new wave of urologists? Graduating urology residents’ practices of and attitudes toward social media
Authors: Jain Kunal , Fuoco Michael B. , Fervaha Gagan , Leveridge Michael J.
Published: March 2018

Introduction: Social media (SoMe) have revolutionized healthcare, but physicians remain hesitant to adopt SoMe in their practices. We sought to assess graduating urology residents’ practices of and attitudes toward SoMe.Methods: A close-ended questionnaire, employing five-point Likert scales, was distributed to all final-year residents (n=100) in Canadian urology training programs in 2012, 2014, and 2016 to assess SoMe usage and perceived usefulness.Results: All (100%) questionnaires were completed. Respondents frequently used online services for personal (100%) and professional (96%) purposes. Most (92%) used SoMe. Many (73%) frequently used SoMe for personal purposes, but few (12%) frequently used SoMe for professional purposes. While a majority (59%) opposed direct patient interaction online, most supported using SoMe to provide patients with static information (76%) and collaborate with colleagues (65%). Many (70‒73%) were optimistic that novel solutions to privacy issues in online communications will arise, making SoMe and email contact with patients conceivable. Few (2‒8%) were aware and had read guidelines and legislations regarding physician online practices; however, awareness of medical associations’ and institutional SoMe policies significantly increased over time (p<0.05).Conclusions: Despite their active online use, graduating urology residents rarely used SoMe in professional settings and were wary of using it in patient care. Nevertheless, they were optimistic toward its integration in urology and supported its use in physician-physician communication. Considering SoMe’s increased influence on urology and graduating residents’ limited awareness of guidelines and legislations, postgraduate medical educators should encourage residents to become more familiar with current online communication recommendations.
Detection of Leguminous Protein in Casein by Nitrogen Stable Isotopes
Authors: Molkentin Joachim
Published: March 2018

Casein can legally be substituted with cheaper leguminous proteins in processed foods, such as imitation cheese, as long as the ingredients are declared. The detection of illegal admixtures of leguminous protein requires analytical procedures to identify an undisclosed adulteration of milk products. To investigate the suitability of stable isotope analyses as an alternative to more sophisticated methods, variations in d15N of soya (n = 27) and peanut (n = 10) protein, as well as casein (n = 14) were determined. Significant differences were established between d15N of casein (4.45 – 6.94‰) and soya (0.25 – 2.37‰) as well as peanut (0.70 – 2.13‰) protein. An average limit of detection for leguminous protein in casein was determined to be 2.1%, provided both components were available for additional analyses. Under practical conditions of food control, i.e., without having access to the actual ingredients, the variability of d15N resulted in an average limit of detection of 26.4%. Because protein d15N can be determined rapidly in crude food samples without elaborate sample preparation, stable isotope analysis can be used as a rapid screening method to determine the presence of higher amounts of leguminous protein in cheese and, in particular, to easily distinguish imitation cheese from cheese.
Sigara Bırakma Polikliniğine Başvuran Hastaların Nikotin Bağımlılığının Sosyo demografik Özellikler ve Depresyon İle İlişkisi
Authors: Velioğlu Usame , Sönmez Cemil Işık
Published: March 2018

Amaç: Bu çalışmada sigara bırakma polikliniğe başvuran

hastaların sigara bağımlılıklarının sosyodemografik özellikler ve depresyon ile

ilişkisini araştırmayı amaçladık.Yöntemler: Bu retrospektif çalışmaya Sigara Bırakma

Polikliniğine Mart 2015 - Kasım 2016 tarihleri arasında başvuran 2119 kişi

dahil edildi. Fagerstrom Nikotin Bağımlılık Testi (FNBT) ve Beck Depresyon

Ölçeği uygulanmış olan hastaların sosyo demografik özellikleri incelendi.

Hastaların nikotin bağımlılığının sosyo demografik özellikler ve depresyon

arasındaki ilişki incelendi.Bulgular: Çalışmadaki hastaların 1468 (%69,3)'i erkek, 651

(%30,7)'i kadındı. Çalışmamızda cinsiyet, medeni durum, eğitim durumu, meslek

durumu, ailede sigara kullanma durumunun FNBT skoru üzerine anlamlı etkisi

olmadığı gözlendi. Yaş gruplarına göre nikotin bağımlılık düzeylerine

bakıldığında"<20" yaş grubundaki nikotin bağımlılık düzeyi düşük

olan bireylerin oranı, "41-50" ve "51-60" yaş

gruplarındakilerden anlamlı düzeyde yüksekti(her biri için p<0,005). Alkol

kullananların nikotin bağımlılığının daha yüksek olduğu anlamlı olarak görüldü

(p=0,011). Nikotin bağımlılığı arttıkça depresyon düzeylerinin arttığı anlamlı

olarak saptandı (p<0,001).Sonuç: Nikotin bağımlılığının alkol ve depresyon ile

ilişkisinin olduğu saptanmıştır. Nikotin bağımlılığı ile mücadelede, hastalar

biyopsiko sosyal yaklaşımla değerlendirilmelidir. Sigara bıraktırma

uygulamalarında özellikle genç popülasyon hedef alınmalıdır.