The influence of saccharin adsorption on NiFe alloy film growth mechanisms during electrodeposition

This article deals with the effects of current modes on saccharin adsorption during NiFe electrodeposition, and, as a consequence, its effect on chemical composition, crystal structure, and microstructure of deposited films. For this purpose, we obtained NiFe films using direct, pulse, and pulse-reverse electrodeposition modes. The deposit composition, crystal structure, and surface microstructure are studied. Direct current (DC) and pulse current (PC) films have a smooth surface, while a pulse-reverse current (PRC) film surface is covered by a volumetric cauliflower-like microstructure. The mechanism of the film surface development was considered from the point of view of saccharin adsorption and its action as an inhibitor of vertical grain growth during different current modes. During the DC and PC modes, saccharin is freely adsorbed on the growth centers and restrains their vertical growth. Whereas in the case of the PRC electrodeposition, saccharin adsorbs during cathodic pulses and desorbs during anodic pulses. Therefore, its inhibiting action decreases, vertical grain growth rises, and a rougher surface develops.

THE INFLUENCE OF FINISHING PROCESSING FEATURES ON THE POLYMERIZED COMPOSITE SURFACE STRUCTURE

The purpose of this work is to assess the influence, feasibility and effectiveness of glycerin as one of the means that prevent the formation of an oxygen-inhibited layer, to search for the most effective polymerization protocol for the final portion of the composite materialThe prepared carious cavities of the first class were sealed with a composite, then the samples were degreased and dried. Since the dental material is a dielectric material and is highly susceptible to charging under the influence of an electron beam, it was decided to apply a thin (30 nm) layer of platinum to the surface of the objects under study.Studies of the surface of the teeth and the applied composite were carried out using a scanning electron microscope (SEM) Tescan Vega 3 SBH.Based on the essence of the mechanism of formation of the oxygen-inhibited composite layer, polymerization protocols were selected. The samples were divided into 4 groups according to each protocol of finishing processing.Based on the study of the surface of composite restoration using a scanning electron microscope (SEM) Tescan Vega 3 SBH, it is concluded that the most optimal protocol for finishing the restoration is polymerization using means that prevent the formation of an oxygen-inhibited layer, and subsequent finishing treatment. This method allows you to achieve a smooth surface of the composite, the absence of pores and microcracks, high-quality edge fit.

TREATMENT OF CHRONIC APICAL PERIODONTITIS: IN A SINGLE OR MULTIPLE VISITS? (REVIEW)

The article describes the effectiveness of the treatment of chronic apical periodontitis in one visit compared to multiple visits. A systematic review of the literature was conducted analyzing articles published on PubMed, Google scholar, ResearchGate and ScienceDirect between 2011 and 2021, treatment effectiveness was the selected outcome variable. A total of 21 articles were selected, 9 of which were selected for detailed review. Chief question in this article was: which treatment approach is more effective? Cleaning, Shaping, disinfecting and obturating in one visit? Or multiple (two) visit protocol? Chronic Apical Periodontitis is treatable in one visit, if done properly. Chronic Apical Periodontitis is treatable in one visit, if done properly, with proper shaping, disinfection, and proper hermetic obturation of the root canal. Bioceramic sealers showed the highest success rate out of all sealers used, the usage of 3-5.25% sodium hydrochloride and 17% ethylenediaminetetraacetic acid showed favorable results, although photodynamic therapy and ultrasonic activated irrigation showed outstanding results.

La, Ce and Nd in the soil-plant system in a vegetation experiment with barley (Hordeum vulgare L.)

Rare earth elements (REEs) have received enormous attention in recent years. However, there are many gaps in the understanding of their behavior in the soil-plant system. The aim of this study is to investigate the behavior of three most common REEs (La, Ce, Nd) in the soil-plant system directly on soil samples using barley (Hordeum vulgare L.) in a vegetation experiment. We attribute the absence of significant changes in plant biomass and photosynthetic pigment content to the reduced availability of REEs in soil samples. The concentration of water-soluble forms of La, Ce and Nd didn't exceed 1 mg/kg, while the concentration of exchangeable forms varied and decreased in a row La > Ce > Nd. The transfer factor (TF) from soil to above-ground biomass was low for all three elements (<1). The stem-to-leaf TF increased with the increase in REEs concentration in soil. The concentration in plant material increased in the row Ce < Nd < La. REEs concentrations in barley leaves didn't exceed 1-3% of the corresponding element concentration in soil samples. REEs concentration in plant tissues is in close direct correlation with the REEs total concentration in soil, water-soluble and exchange forms. REEs concentration in barley leaves is 3-4 times higher than in the stems and for the group with extraneous concentration of 200 mg/kg for La, Ce and Nd was 6.20 ± 1.48, 2.10 ± 0.51, 6.90 ± 3.00 mg/kg, respectively. We show that there were no major changes in barley plants, but further study is needed of the relationship between the absorption of lanthanides by plants and the content of various forms of lanthanides in the soil.

Toxicity assay of lanthanum and cerium in solutions and soil

Lanthanum (La) and cerium (Ce) are one of the most abundant rare earth elements (REEs). In spite of quite extensive studying of the effects of these lanthanides on biota, some contradictions remain in the results. Also little is known about the effect of lanthanum and cerium on plant cells and their mitotic cycle, especially in soils. In this study, the effects of La and Ce in solutions and soil samples on root growth, mitotic index (MI) and frequency of aberrant cells (FAC) were assayed using one of the most convenient objects for testing of cytotoxicity - onion Allium cepa L. Bulbs were germinated on media containing La and Ce in concentrations 0-200 mg/l and 0-50 mg/l respectively for solutions and 0-200 mg/kg for soil samples. After 5 days of germination in solutions, a significant decrease in root elongation and MI in apical meristem cells are shown. We have also observed an increase in the number of cells with aberrations at 50 mg/l La and Ce concentration. The number of observed stickiness and disturbed metaphase has increased significantly. Soil samples turned out to be less toxic compared to the solutions probably due to the decreased availability of REEs. In spite of this, significant cytotoxicity of soil samples containing the highest concentration of La and Ce (200 mg/kg) is observed. The latter may indicate the importance of considering the cytotoxicity of soils containing high lanthanides concentrations - in extraction and production areas and actively fertilized fields.

Application of tissue Doppler to interpretation of exercise echocardiography: diagnostics of ischemia localization in patients with ischemic heart disease

Development of optimal methods for the objective non-invasive diagnosis of coronary artery disease remains a challenge for imaging techniques in stress tests.

AIM

The aim of this study was to obtain quantitative diagnostic criteria TDI which could detect significant coronary artery disease during exercise echocardiography.

METHODS AND RESULTS

We evaluated regional systolic and diastolic myocardial functions of 123 patients by pulsed wave tissue Doppler imaging (TDI) in eight segments of left ventricle during exercise stress testing. Diagnostic criteria were obtained by comparing TDI and coronary angiography data. Best cut-points of velocity parameters allowed developing two diagnostic models for the detection of left anterior descending (LAD) and circumflex (LCx) artery diseases. The accuracy of the TDI diagnostic model for LAD-disease was 86.2% and for LCx-disease 78.3%. There were no criteria for the detection of RCA disease in this study.

CONCLUSION

So TDI is a very accurate method for the detection of LAD- and LCx-disease during exercise stress echocardiography.