Decreased Serum Selenium Levels of COVID-19 Patients in Comparison with Healthy Individuals.

BACKGROUND: Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is the cause of the COVID-19 pandemic and is the cause of increased mortality, especially among elderly patients and those who have severe complications, such as chronic pulmonary obstruction, hypertension, diabetes, and cancer. Nutrition, especially micronutrients, plays an important role in reducing mortality and complications from COVID-19 because micronutrients strengthen our immune system and nutritional status is an important factor that affects the outcome of patients with COVID-19. Among micronutrients, selenium has an important effect on both intrinsic and acquired immunity. Host selenium deficiency affects the viral genome and increases the virulence of viruses. We have investigated the serum selenium levels in COVID-19 patients and healthy control individuals. METHODS: A total of 50 patients with COVID-19 infection were included in this study. During hospitalization, 13 patients died (non-survivor group) and 37 patients recovered (survivor group). We assessed the serum selenium levels in 50 COVID-19 patients and 50 healthy individuals by Agilent SpectrAA-240 Z atomic absorption spectrometer. RESULTS: The serum selenium level was significantly lower in COVID-19 patients (77. 8 ± 13.9 µg/L) as compared to healthy control individuals (91.7 ± 16.7 µg/L), but there was no significant difference between the survivor and non-survivor groups. Also, there was no significant relationship between serum selenium levels and laboratory findings of COVID-19 patients. CONCLUSIONS: These results suggest that decreased serum selenium levels may be a risk factor for the COVID-19 infection, but there was no significant relationship between selenium and severity and mortality of COVID-19 disease.

Combined effects of calcium hydroxide and photobiomodulation therapy on apexogenesis of immature permanent teeth in dogs.

Treatment of high-risk traumatic immature teeth due to incomplete root development is challenging. Apexogenesis is currently the ideal treatment option that allows normal root development. The purpose of this study was to evaluate the apexogenesis process of immature permanent teeth of dogs when co-administered with calcium hydroxide and photobiomodulation therapy (PBMT). A total of 36 immature permanent anterior and premolar teeth were selected from three 4-6-month-old dogs of Iranian mixed generation. The teeth were categorized into two groups, calcium hydroxide with laser irradiation (CHL) and calcium hydroxide without laser irradiation (CH). All the selected teeth received calcium hydroxide pulpotomy. After restoring teeth with amalgam, the CHL group received gallium­aluminum-arsenide (GaAlAs) diode laser (810 nm, 4.2 J/cm2, 0.3 W, 9 s,CW) on apical one-third of both buccal and lingual roots. The irradiation was repeated every 48 h for fourteen days. Intravenous tetracycline was used to observe newly formed dentin in the first, third, seventh, and fourteenth days. The distance between tetracycline lines (DTL) was examined by Fluorescence microscopy. Generalized estimating equations (GEE) were used for data analysis. In all assessments, the mean DTL were greater in the CHL group. However, the two groups had no significant differences in the amount of deposited dentin between the first and third, third and seventh, and first and seventh lines. Meanwhile, there was a significant difference between the two groups in terms of the distances between lines 7 and 14, 1 and 14 and also 3 to 14 (P < .001). In other words, from the 7th day onwards, there was a significant difference between the two groups. Within the limitation of this study, the combination therapy of PBMT and pulpotomy with calcium hydroxide accelerated apexogenesis in immature permanent dogs' teeth.

A novel natural chitosan/activated carbon/iron bio-nanocomposite: Sonochemical synthesis, characterization, and application for cadmium removal in batch and continuous adsorption process.

The natural chitosan was synthesized using shrimp shells via sonochemical method, and activated carbon produced from grape stalks biomass. The novel bio-nanocomposite of chitosan/activated carbon/iron nanoparticles was synthesized via the sonochemical method and characterized using FTIR, SEM, and BET techniques. This bio-based nanocomposite was utilized to cadmium removal from dilute solution. The adsorption process via batch method was optimized, and the impacts of pH of feed, the dosage of adsorbent, and concentration of cadmium were analyzed. The kinetics and equilibrium analysis was done, and results indicate the predomination of chemical absorption and the single-layer adsorption process. Langmuir data indicates that the synthesized bio-nanocomposite can adsorb 344 mg cadmium per each gram. To evaluate the ability of the synthesized nanocomposite in the industrial application, the adsorption tests were done in a continuous adsorption system in three cycles.

Instability-Assisted Direct Writing of Microstructured Fibers Featuring Sacrificial Bonds.

A 30 µm-diameter thread of poly(lactic acid) (PLA) dissolved in dichloromethane is deposited on top of the eye of a sewing needle. The deposition robot traces a straight line; the helical shape of the thread is due to the liquid rope coiling instability. This instability is used to fabricate microstructured fibers with tailored mechanical properties.