Introduction:The pathological processes of pulmonary hypertension and COVID-19 disease are similar. Both are characterized by vascular damage, severe micro thrombosis, and microvascular obliterative disease due to extensive endothelial dysfunction.Objective:It was planned to present the clinical, radiological, and biochemical data of patients with pulmonary arterial hypertension(PAH) and Chronic Thromboembolic Pulmonary Hypertension (CTEPH) diagnosed with COVID-19, who were followed up in our pulmonary arterial hypertension (PAH) center, as well as to assess the survival rates and to investigate the factors impacting survival.Methods: Patients who were diagnosed with COVID-19 between March 2020 and July 2021 and were followed up in the PAH center of our hospital, were included in the study. All information were obtained from the records in the hospital automation system. Results:It was found that 24(7.2%) of the 331 patients who had been followed in the PAH center were diagnosed with coronavirus. The mean age of the patients was determined to be 53.54. It was found that 62.5% of the patients were female,54.2% had the etiology of CTEPH and 41.7% of the patients were in functional class II(WHO-FC II) before being infected with COVID-19.The survival rate was 79.2%. It was found out that the risk of mortality decreased by 0.007 times as the cardiac index increased, and the risk of mortality increased 10,233 times as the functional class increased.Conclusion:Mortality rates due to COVID-19 infection were determined to be higher in PAH/CTEPH patients. The cardiac index values and current functional classes of the patients were associated with survival.

Purpose: The aim of our in vitro study was to investigate the marginal leakage of class V cavities prepared by conventional diamond bur and Er:YAG laser. Materials and methods: 45 single rooted intact extracted human teeth were used. They were randomly assigned into three groups, dependent on the preparation technique: Group I (n=15) – diamond bur + total-etch technique; Group II (n=15) – Er:YAG laser + total-etch technique; Group III (n=15)– Er:YAG laser + laser etching. Microleakage was assessed according to the depth of dye penetration along the restoration at x 15 magnification. Results: None of the procedures investigated on our study completely eliminated the microleakage. The extent of dye penetration was lowest in the laser-treated and acid-etched group (Group II). Conclusions: The results of our study revealed that the laser irradiation can modify the morphology of the cavity walls and increase the bond strength with the composite filling.\n Keywords: Er:YAG laser, cavity preparation, microleakage, composite

Dental caries is one of the most common chronic diseases in the world, affecting 60-90% of school-age children and almost 100% of the adult population. Disease prevention at early ages is a fundamental public health principle and particularly relevant for dental caries.\nOne modern alternative method, gaining popularity in recent years is the application of lasers in clinical practice. Different type of laser systems are used in conservative dentistry in several fields as carious lesions diagnosis, desensitization of hypersensitive teeth, remineralisation of initial carious lesions and dental caries treatment.\n\n\nKey words: laser, dental caries, photodynamic therapy, photoactivated desinfection

Purpose: The aim of our in vitro study was to evaluate the effect of diode laser irradiation (λ=660 nm and λ=970 nm) on the intracanal dentin and their interference in the apical seal of filled root canals. Materials and methods: 48 human single rooted teeth were randomly assigned into 4 groups. Root canal preparation was done using ProTaper Universal rotary system up to F3. 2 % Sodium hypochlorite, 17 % EDTA and distilled water were used as irrigants. The laser irradiation was performed at the end of the traditional endodontic preparation and teeth were filled with gutta-percha and AH- plus. The apical leakage was report on mm. Results: Statistical analysis showed that the laser-treated groups had significantly less leakage in apical third than the control group. Conclusions: Certain lasers can help in removing the smear layer and debris and can modify the morphology of the root canal wall for better root canal sealing.\n Keywords: diode laser, apical leakage, Protaper rotary instruments

Photovoltaic (PV) system is integrated in microgrids because of the ability to trap renewable energy as secondary power sources. In this paper, the decentralized control scheme is proposed based on the optimum offset voltage gain in order to extract equal power sharing of the distributed PV source converters within the permissible bus voltage regulation of low voltage DC Microgrid. Moreover, the impact of unequal cable line impedances of the distributed sources is compensated by utilizing the optimal offset voltage for constant power loads (CPLs). Hybrid Particle Swarm–Nelder–Mead (PSO–NM) optimization algorithm is utilized for the optimal value of the offset voltage gains and voltage controller parameters. The stability analysis of the DC system is also performed for a specified range of droop gains and CPLs. The control scheme is utilized a hysteresis current controller and proportional-integral controller for renewable energy sources without any communication link. Three PV sources based on the proposed control scheme are performed with resistive and CPLs in the MATLAB/Simulink environment and verified by experimental results on FPGA-based hardware-in-loop (HIL) on a real-time simulator.