Direct Probing of Dispersion Quality of ZrO2 Nanoparticles Coated by Polyelectrolyte at Different Concentrated Suspensions.

This study reports useful application of the electrokinetic sonic amplitude (ESA) technique in combination with rheometry and electron microscopy techniques for direct probing the stability of low and high-concentrated zirconia (ZrO2) nanosuspensions in the presence of an alkali-free anionic polyelectrolyte dispersant Dolapix CE64. A comparative study of the electrokinetic characteristics and the rheological behavior of concentrated ZrO2 nanosuspensions has been done. Good agreement was obtained from relationship between the electrokinetic characteristics (zeta potential, ESA signal), viscosity, and its pH dependence for each concentrated ZrO2 nanosuspension with different dispersant concentration in the range of 0.9-1.5 mass%. A nanoscale colloidal hypothesis is proposed to illustrate that the addition of different amounts of dispersant influences on both the stability and the electrokinetic and rheological properties of concentrated ZrO2 nanosuspensions. It is found that an optimum amount of 1.4 mass% dispersant at the inherent pH (>9.2) can be attached fully onto the nanoparticles with sufficient electrosteric dispersion effects, suitable for casting applications. Supplementary scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM) analyses followed by colorization effect were taken to verify the visible interaction between dispersant and nanoparticles surfaces. SEM and HR-TEM images proved the existence of visible coverage of dispersant on the surface of individual nanoparticles and showed that thin polyelectrolyte layers were physically bound onto the particles' surfaces. This study will be of interest to materials scientists and engineers who are dealing with dispersion technology, nanoparticle surface treatments, functionalization, characterization, and application of bio/nanoparticle suspensions at various concentrations using different types of polymers

The potential of highly nutritious frozen stages of Tyrophagus putrescentiae as a supplemental food source for the predatory mite Amblyseius swirskii

Astigmatid mites have potential as supplementary prey items to support generalist predator populations in crops. However, applying living prey mites has some disadvantages; if not predated they have the potential to cause crop damage and allergies. In this study, we evaluated various diets based on the astigmatid mite Tyrophagous putrescentiae (Schrank) as a supplemental food source for the predatory mite Amblyseius swirskii Ahias-Henriot. Eggs and larvae of T. putrescentiae were reared on a diet of dog food (rich in proteins and fat) or bran (rich in carbohydrate); they were offered either frozen or alive, and either with or without cattail pollen (Typha angustifolia L.). Oviposition rate of A. swirskii fed with frozen mite larvae reared on dog food was similar to the rate observed when they were fed with cattail pollen or living prey mites, but developmental time of A. swirskii was longer on this frozen diet than on a diet of living prey mites or pollen. Both living and frozen prey mites were, in contrast with cattail pollen, not suitable for oviposition by western flower thrips, Frankliniella occidentalis Pergande. In a greenhouse study, the use of frozen prey mite stages as supplemental food on chrysanthemum plants allowed populations of A. swirskii to establish, but not increase; in contrast, provision of living prey mites and pollen increased A. swirskii populations on plants. Hence, our study shows that living prey mites, but not frozen prey mites, had the greatest potential as a supplemental food source for A. swirskii.</p

The Most-cited Articles in Dentistry Up to 2017

Introduction: Citation analysis is a suitable way to help us to identify research trends within a specific topic. The purpose of this study was to identify the 100 most cited articles in the field of dentistry published over the past 67 years. Methods: A comprehensive list of the most cited articles in dentistry was compiled using ISI Web of Science. The characteristics including number of citations, authors and journals were analyzed. Results: The database resulted in 3,831 articles with 100 or more citations published between 1950 and 2017. Most of these articles had been published by the Journal of Clinical Periodontology, followed by the Journal of Periodontology, and Journal of Dental Research. Sokransky SS followed by Lindhe J, Nyman S, and Genco RJ had the most number of citations. Conclusion: The most cited articles in the field of dentistry allows for advances in this field and also provide useful information for direct future studies and patient care

The Effect of LiFePO 4 Coating on Electrochemical Performance of LiMn 2 O 4 Cathode Material

ABSTRACT: LiMn 2 O 4 spinel cathode materials have been successfully synthesized by solid-state reaction. Surface of these particles were modified by nanostructured LiFePO 4 via sol gel dip coating method. Synthesized products were characterized by thermally analyzed by Thermogravimetric and Differential Thermal Analysis(TG/DTA), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive X-ray (EDX) spectroscopy. The results of electrochemical tests showed that the charge/discharge capacities improved up to 120 mAh/g and charge retention of battery enhanced over %95. This improved electrochemical performance is caused by LiFePO 4 phosphate layer on surfaces of LiMn 2 O 4 cathode particles

Active and frozen host mite Tyrophagus putrescentiae (Acari : Acaridae) influence the mass production of the predatory mite Blattisocius mali (Acari: Blattisociidae): life table analysis

Blattisocius mali (Oudemans) is a candidate predatory mite on some astigmatid mite pests like Tyrophagus putrescentiae (Schrank). In current study, life table parameters of B. mali were comparatively evaluated when fed on mixed life stages, frozen (one day at-20°C) and cold stored (90 days at-20°C and 4°C) eggs of T. putrescentiae. The highest and lowest values of fecundity, total longevity, oviposition period, life span and adult longevity of B. mali were observed when the predator provided with one-day and 90-days frozen eggs (stored at 4°C) of T. putrescentiae, respectively. Moreover, the highest values of net reproductive rate (R0), intrinsic rate of increase (r) and finite rate of increase (λ) of B. mali were obtained by feeding on one-day frozen eggs (23.94 offspring/individual, 0.332 day-1, 1.39 day-1, respectively), without significant differences from the predators reared on alive mixed stages of T. putrescentiae. However, the lowest values of R0 (1.54 offspring/individual), r (0.058 day-1) and λ (1.06 day-1) were recorded when B. mali was reared on 90-days frozen eggs (stored at 4°C). The results, as first evidence of life-history of B. mali, represent not only the potential of the predator as suitable biological control agent against T. putrescentiae, but also the possibility of its mass production by frozen host stages. Provision of one-day frozen eggs of T. putrescentiae were the best choice for B. mali survival and reproduction with no harmful effects of living stages (direct damage, frass and exuviae) on crop

A child with Moyamoya Disease: Case Report

Cerebral stroke is a rare disease in children. Moyamoya (MM) is one of the infrequent cerebrovascular diseases with unknown etiology. We report an 8 year-old-boy with chief complain of sudden onset bilateral parietal lobe headache. He mentioned that his headache was first started about three weeks ago and was associated with visual disturbance. His mother declared that the boy developed gait problems few days later and only could walk with assistance. He was diagnosed with MM disease. After, medical treatment his symptoms were mildly improved and because of   his family disagreement cerebral revascularization surgery was not performed

Effect of zirconia nanotube coating on the hydrophilicity and mechanochemical behavior of zirconium for biomedical applications

Zirconium has attracted considerable attention in the biomedical field owing to its biocompatibility and desirable tribological and mechanical properties. In this study, we anodized pure zirconium in an ammonium fluoride and ethylene glycol electrolyte, which produced a coating of ZrO2 nanotubes (NTs). The ZrO2 coated samples were annealed at different temperatures, and the morphology and structure of the coated substrates were studied using XPS, SEM, TEM, EDS, and SAED. The micro/nanomechanical properties and corrosion resistance of the samples were evaluated. Wear tests performed on bare and coated substrates revealed that the coated samples annealed at 400 °C had a significantly lower average coefficient of friction than the other substrates. The corrosion test was performed on different substrates, and the results showed that the corrosion resistance of the coated sample annealed at 400 °C was considerably higher than that of the other substrates. According to the nanoindentation tests, the elastic modulus of the Zr sample decreased from 74.3 to 31.7 GPa after anodization and the creation of ZrO2 NTs. Biocompatibility tests revealed that cell attachment to the surface of the ZrO2 NTs decreased due to the presence of F−; however, the cell viability increased after the ZrO2 NT-coated samples were annealed at 200 and 400 °C.This work was supported by the National Research Foundation of Korea (grant number NRF-2020R1A4A1019074 ) and the Qatar National Research Fund, the Qatar Foundation, Doha, Qatar (grant number NPRP11S-0102-180178 ). The authors also would like to acknowledge University of Malaya and Sharif University of Technology for supporting this research.Scopu