Antimicrobial efficacy of nanosilver, sodium hypochlorite and chlorhexidine gluconate against Enterococcus faecalis

The purpose of this study was to compare the antibacterial efficacy of nanosilver (NS), chlorhexidine gluconate (CHX) and sodium hypochlorite (NaOCl) against Enterococcus faecalis. Two tests of minimum inhibitory concentration (MIC) and zone of inhibition were carried out using NS, NaOCl and CHX. 70-fold concentration of NaOCl is required for the same antibacterial effect of NS. CHX precipitated in contact with the culture medium and was excluded from MIC test. The means and standard deviations of the zones of inhibition for 5.25% NaOCl, 0.33% NaOCl, 25 μg/ml NS, 50 μg/ml NS, 4000 μg/ml NS and 2% CHX were 12.16 ± 1.46, 6.91 ± 0.66, 10.00 ± 0.42, 12.00 ± 0.60, 13.33 ± 1.23 and 24.80 ± 1.11, respectively. Statistical analysis using ANOVA showed significant differences among groups (p < 0.001). A post hoc Tukey test revealed no significant differences between 5.25% NaOCl and 4000 μg/ml NS (p = 0.057). However, the zones of inhibition for 2% CHX were significantly larger than those seen around the filter papers saturated with undiluted NaOCl and NS (p < 0.001 for both). This study revealed that NS in a remarkably lower concentration would possess the same bactericidal effect as 5.25% NaOCl.Key words: Chlorhexidine gluconate, Enterococcus faecalis, nanosilver, sodium hypochlorite

Clinical efficacy of convalescent plasma for treatment of COVID-19 infections: Results of a multicenter clinical study

Since Dec. 2019 the new coronavirus (SARS-CoV-2) has infected millions and claimed life of several hundred thousand worldwide. However, so far no approved vaccine or drug therapy is available for treatment of virus infection. Convalescent plasma has been considered a potential modality for COVID-19 infection. One hundred eighty-nine COVID-19 positive patients including 115 patients in plasma therapy group and 74 patients in control group, registered in the hospitals with confirmed COVID-19 infection, entered this multi-center clinical study. Comparison of outcomes including all-cause mortality, total hospitalization days and patients� need for intubation between the two patient groups shows that total of 98 (98.2 ) of patients who received convalescent plasma were discharged from hospital which is substantially higher compared to 56 (78.7 ) patients in control group. Length of hospitalization days was significantly lower (9.54 days) in convalescent plasma group compared with that of control group (12.88 days). Only 8 patients (7) in convalescent plasma group required intubation while that was 20 in control group. This clinical study provides strong evidence to support the efficacy of convalescent plasma therapy in COVID-19 patients and recommends this treatment for management of these patients. Clinical efficacy, immediate availability and potential cost effectiveness could be considered as main advantages of convalescent plasma therapy. © 2020 Elsevier Lt

Investigation of the spectroscopic features along with the media polarity effect in some symmetrical disc-shaped liquid crystals

Disc�shaped liquid crystals with interesting structural features are an important research field in the science and technology. Function of these strongly depends on their molecular structure and the media that surrounds them. This paper highlights spectral features of three symmetrical disc�shaped liquid crystals with similar structures and dissimilar substituent groups in various surrounding media to recognize their interactional and structural similarities and differences. Determining the type of molecular interactions in these liquid crystals and their effect is of great importance in accurate determination of host�guest interactions for diverse applications in polymer�dispersed liquid crystal displays, elastomers and optical industries, and so on. For this purpose, spectral variations were analyzed through KAT (Kamlet�Abboud�Taft) model and the dipole moments were measured through UV�visible spectroscopic technique, too. The dipole moment results reveal that the electron cloud resides in the central part of these liquid crystals. The experimental data were validated via DFT (Density Functional Theory) calculations. Both experimental and theoretical data assist to better identify the spectroscopic features of these liquid crystals and give useful information about their performance in various media that can be valuable for designing applicable guest�host or mixture liquid crystal systems. © 2018 Elsevier B.V