Comparison of Cyclic Fatigue Resistance of Five Heat Treated NiTi Rotary Systems in Single and Double Curved Canals.

BackgroundThe aim of this study was to compare cyclic fatigue resistance (CFR) and separation patterns during rotating movement of five heat-treated nickel titanium files in both single and double-curved canals. MethodsCFR was compared between five groups of 24 files each: HyFlex® EDM, HyFlex™ CM, Vortex Blue®, Protaper Next®, and One Curve, by determining the time needed to fracture (TTF) and the number of cycles to failure (NCF) in a cyclic fatigue testing device with a single 5-mm radius of curvature (ROC) and 60° angle, and a double curvature; coronal curvature (5 mm ROC and 60° angle) and apical curvature (2 mm ROC and 70° angle). The separation pattern was evaluated, and file fragment separated length were measured. One-way ANOVA and Tukey’s post-hoc were used to compare statistical differences between the groups. Scanning Electron Microscope (SEM) was used to investigate the fracture sites. Results HyFlex™ CM files displayed significantly higher CFR, followed by HyFlex® EDM and Vortex Blue® in single curvature canals, and Protaper Next® (PTN) in the double curvature canals, as observed by TFF and NCF. PTN group had the highest tendency for files to extrude apically after separation in both curvatures. ConclusionHyFlex™ CM instruments have superior resistance to cyclic flexural fatigue within single canals with single and double curvatures, followed by HyFlex® EDM and Vortex Blue® instruments. Protaper Next® files followed by One Curve had the highest tendency to extrude apically after separationClinical relevanceHyFlex™ CM instruments showed the highest safety in preparing canals with single or double curvatures, considering CFR.

Validated Simultaneous Gradient Ultra-Performance Liquid Chromatographic Quantification of Some Proton Pump Inhibitor Drug Residues in Saudi Pharmaceutical Industrial Wastewater

Monitoring and quantification of active pharmaceutical ingredients (APIs) in the environment constitute important and challenging tasks, as they are directly associated with human health. Three commonly used proton pump inhibitors (PPIs), namely, omeprazole sodium (OMP), pantoprazole sodium (PNT), and lansoprazole sodium (LNZ) are well separated and quantified using ultra-performance liquid chromatography (UPLC) in pharmaceutical industrial wastewater. The separation of the studied drugs was performed on a stationary phase with a WatersTM column (100 × 2.1 mm, 1.7 µm). The mobile phase was composed of methanol:0.05 M potassium dihydrogen phosphate buffer (adjusted to pH 7.5 using NaOH) (50:50, v/v). The elution process was done in gradient mode by changing the relative proportions of the mobile phase components with time to get an optimum separation pattern. The flow rate of the developing system was adjusted to 0.8 mL/minute. Detection of the separated drugs was performed at 230 nm. The studied drugs were quantified in the concentration range of 10–200 ng/mL for all drugs. The cited method was fully validated according to the international conference on harmonization (ICH-Q2B) guidelines, then it was applied successfully for quantification of the studied PPIs in real wastewater samples after their solid phase extraction (SPE).

Development and Use of New Polymer Adhesives for the Restoration of Marine Equipment Units

A new adhesive material and a restoration technology for marine equipment units are proposed. The optimal content of hardeners of different nature is found, and the effect of temperature conditions used for crosslinking epoxy resin DER-331, on the adhesive properties of the polymeric material is determined. The polymerization of the epoxy oligomer DER-331 and polyethylene polyamine (PEPA) hardener at a temperature T = 413 ± 2 K is found to enhance the adhesive properties of the polymeric material by 3.2–3.6 times, as compared to polymer GEN-150. In addition, the separation pattern of metal surfaces was analyzed, which allowed for an in-depth evaluation of the adhesive strength at separation and its variation upon increasing the content of hardeners introduced. Based on complex studies, it is shown that the developed polymeric adhesive should be used in the restoration of marine transport units, in particular, wheel fit in the compressor section of turbocharger.

Elevation influence the macrofungi diversity and composition of Gunung Korbu, Perak, Malaysia

Nur ‘Aqilah MB, NurJannah S, Salleh S, Thi BK, Ahmad Fitri Z, Mohd Khairul Faizi M, Haja Maideen KM, Nizam MS. 2020. Title. Biodiversitas 21: 1707-1713. Fructification of macrofungi depends on two main factors, abiotic and biotic. In this study, the main focus is to determine the macrofungi composition and diversity as the effect of elevation and substrate. Macrofungi collection was conducted at three different elevations along the trails (Trail A, B, and C) of Gunung Korbu in July 2019. The sampling area was divided by ascent elevation from the Seroja Camp to the Rimba Gate (Trail A, 796 m above sea level[a.s.l]), the Seroja Camp to the Kijang Camp (Trail B, 1092 m a.s.l) and the Kijang Camp to the summit of Gunung Korbu (Trail C, 2183 m a.s.l). The collected macrofungi were photographed, described based on their macroscopic characters and any colour changes when bruising or chemicals reactions were recorded. In total 90 macrofungi specimens were in good condition belonging to 6 families from 13 genera, including the unidentified. About 93.33% (84 specimens) of the collections are saprotrophic fungi and six parasitic fungi. Trail B recorded the highest diversity index of 2.20 and 0.87 for Shannon Index and Simpson index, respectively. Non-metric multidimensional scaling ordinations showed a clear separation pattern of macrofungi community found in three different trails, with most of the specimens found in Trail B.

On the aerodynamic flow around a cyclist model at the hoods position

Aerodynamic flow around an 1/5 scale cyclist model was studied experimentally and numerically. First, measurements of drag force were performed for the model in a low-speed wind tunnel at Reynolds numbers from $$5.5 \times 10^{4}$$5.5×104 to $$1.8 \times 10^{5}$$1.8×105. Meanwhile, numerical computation using a large eddy simulation method was performed at three Reynolds numbers of $$1.1 \times 10^{4}$$1.1×104, $$6.5 \times 10^{4}$$6.5×104 and $$1.5 \times 10^{5}$$1.5×105 to obtain the drag coefficients for comparison. Second, flow visualization was made in a water channel and the wind tunnel mentioned to examine the three-dimensional flow separation pattern on the model surface, which could also be realized from the numerical results. Finally, a wake flow survey based on the hot-wire measurements in the wind tunnel showed that in the near-wake region, the flow was featured with the formation of multiple streamwise vortices. The numerical results further indicated that these vortices were evolved from the separated flows occurred on the model surface. Graphic Abstract

Modular nature of simian foamy virus genomes and their evolutionary history

Among all known retroviruses, foamy viruses (FVs) have the most stable virus–host co-speciation history, co-diverging in concert with their vertebrate hosts for hundreds of millions of years. However, detailed molecular analyses indicate that different parts of their genome might have different evolutionary histories. While their polymerase gene displays a robust and straightforward virus–host co-speciation pattern, the evolutionary history of their envelope (env) gene, is much more complicated. Here, we report eleven new FV env sequences in two mandrill populations in Central Africa, geographically separated by the Ogooué River into the North and the South populations. Phylogenetic reconstruction of the polymerase gene shows that the two virus populations are distinct, and each contains two variants of env genes co-existing with one another. The distinction between the two env variants can be mapped to the surface domain, flanked by two recombination hotspots, as previously reported for chimpanzee and gorilla FVs. Our analyses suggest that the two env variants originated during the diversification of Old World monkeys and apes, ∼30 million years ago. We also show that this env gene region forms two phylogenetically distinct clades, each displaying a host co-divergence and geographical separation pattern, while the rest of the genome of the two strains is phylogenetically indistinguishable in each of the host-specific groups. We propose possible evolutionary mechanisms to explain the modular nature of the FV genome.

Quantum gauge transformation, gauge-invariant extension and angular momentum decomposition in Abelian Higgs model

I discuss the momentum and angular momentum decomposition problem in the Abelian Higgs model. The usual gauge-invariant extension (GIE) construction is incorporated naturally into the framework of quantum gauge transformation à la Strocchi and Wightman and with this, I investigate the momentum and angular momentum separation in a class of GIE conditions which correspond to the so-called “static gauges”. Using this language, I find that the so-called “generator criterion” does not generally hold even for the dressed physical field. In the case of U(1) symmetry breaking, I generalize the standard GIE construction to include the matter field degrees of freedom so that the usual separation pattern of momentum and angular momentum in the unitarity gauge can be incorporated into the same universal framework. When the static gauge condition could not uniquely fix the gauge, I show that this GIE construction should be expanded to take into account the residual gauge symmetry. In some cases, I reveal that the usual momentum or angular momentum separation pattern in terms of the physical dressed field variables needs some type of modification due to the nontrivial commutator structure of the underlying quantum gauge choice. Finally, I give some remarks on the general GIE constructions in connection with the possible commutator issues and modification of momentum and angular momentum separation patterns.

CRIMINALISTICS RESEARCH OF SEMISYNTHETIC MOTOR OILS OF FOREING AND DOMESTIC PRODUCTION

Characteristics of engine oils exterior in spectrum UV region, solubility parametres are determined. By results of research it’s established that all types of the investigated engine oils are characterized by similar colour characteristics, ability to solubility in liquids of various nature and polarity. The results of researches of structurally-group composition of some semisynthetic oils offoreign and domestic production with the use of methods of thin-layer chromatography and IR-spectroscopy are presented. The use of IR-spectroscopy method gives the basic information on the structure of investigated objects under condition of registration of corresponding absorption bands, and also makes it possible to detect the presence ofadditives ofantioxidant, dispersive and viscous purpose. An obstacle for reliable interpretation of IR spectra at an establishment of oil concrete type (mineral, semisynthetic or synthetic) is the presence of common intensive absorption bands, and also imposing of more intensive bands on less intensive (masking). Efficiency of this method use for an establishment of oil type is situational. It depends on composition which is defined by the manufacturer. In order to obtain more informative IR spectra we may recommend a classical method of registration - using liquid cuvettes or in a thin layer between the plates made from KBr. The use of the thin-layer chromatography method has shown possibility of semisynthetic oils differentiation from mineral and synthetic oils under condition of complex processing of chromatograms with the Marki reactant, iodine vapors and examination in UV-beams. It’s ascertained that received chromatograms of semisynthetic oils have an overall separation pattern with motor and synthetic oils. At that chromatograms of mineral and synthetic oils essentially differfrom each other. Thus, attributing oils to semisynthetic becomes possible when obtaining a chromatographic separation pattern in a thin layer of a sorbent at set of signs characteristic both for mineral and for synthetic oils.