Background and Aim: Discoloration is among the most common problems of composite restorations. Color change over time compromises the main advantage of composite resins namely their high esthetics. In such cases, the restoration needs to be replaced. .The aim of this in-vitro study was to evaluate the effect of accelerated Artificial aging (AAA) on the color stability of three composite resins (Filtek Z250, Filtek Z250XT, and Filtek Supreme). Materials and Methods: In this experimental study, 7 composite specimens with equal dimensions were fabricated of each composite resin. The initial color of specimens was measured using a spectroradiometer according to the CIE L*a*b* system. The specimens were then submitted to AAA for 384h and underwent color assessment again. Before and after aging, the surface roughness of one specimen from each group was determined by Atomic Force Microscopy (AFM). The obtained color parameters were analyzed by one-way ANOVA and Tukey’s test. Results: The color change of Filtek Z250 was significantly lower than that of Filtek Z250XT and Filtek Supreme (P≤0.05). No statistically significant differences were found between Z250XT and Supreme in this respect (P>0.05 ). Conclusion: All composite resins showed color change above the clinically acceptable threshold. Z250 microhybrid composite was more color stable than nano-composites (Z250XT and Supreme). AAA increased the surface roughness in all groups but it was within the clinically acceptable range.

Electron transport system (ETS) activity was found to be related to the initial inoculum size, culturability and viability of E. coli. In this experiment, ETS activity of Flexibacter chinensis was measured by INT-method under a variety of conditions such as starvation media with different amendments and different temperatures. The relation between ETS activity, cell culturability, and viability was investigated. We found that the addition of glucose increased ETS activity without affecting cell culturability. Urea addition led to an increase in survival, but did not increase ETS activity.

Influenza is an acute viral respiratory disease with diverse clinical manifestations. Despite extensive research, ambiguities remain regarding its prognostic factors. In this cross-sectional retrospective study, conducted during 2021 on 993 samples (546 males 447 females) from patients with suspected acute viral respiratory infections who were hospitalized in hospitals of Golestan Province, we evaluated the clinical and laboratory findings of patients with influenza. The samples were sent to the provincial molecular diagnostics laboratory for real-time polymerase chain reaction (PCR) molecular testing. All samples were also tested for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Test results, along with demographic, clinical, and laboratory data, were collected using a standardized questionnaire. Of the 993 samples tested for influenza, 174 were reported as positive. All, but one, of these positive cases were influenza A. From 993 tests for SARS-CoV-2, 271 cases were also reported as positive. Additionally, 11 patients had influenza and SARS-CoV-2 co-infection. The mean age of influenza patients hospitalized in the intensive care unit (ICU) was determined to be 55.60±15.11 years, while in other wards, it was 37.51±12.1 years (P<0.05). Regarding gender, the ICU-hospitalized male-to-female ratio was 3 times and 1.35 times in other wards (P<0.05). In ICU-hospitalized patients, the highest percentage of clinical symptoms belonged to fever, cough, chills, and anorexia, and in patients hospitalized in other wards, the highest percentage belonged to fever, followed by cough, chest pain, and chills. There was a statistically significant difference between ICU-hospitalized patients and those hospitalized in other wards for symptoms, such as anorexia, arthralgia, myalgia, sore throat, cough, nausea, headache, and chills (P<0.05). Blood factors, such as white blood cell (WBC) count, neutrophil and lymphocyte percentages, hemoglobin, erythrocyte sedimentation rate (ESR), and platelets, were evaluated, and no statistically significant difference was observed between the two patient groups. Biochemical factors, including blood urea nitrogen (BUN), creatinine, sodium, potassium, liver enzymes, such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), lactate dehydrogenase (LDH), creatine phosphokinase (CPK), and direct and indirect bilirubin, were also examined, and no significant difference was found between the two patient groups. Additionally, other factors, such as oxygen and carbon dioxide saturation percentages, bicarbonate, and blood pH were assessed, and a statistically significant difference was found between the two groups for oxygen and carbon dioxide saturation percentages (P<0.05). Based on the findings of this study, age and gender are effective factors in the severity of influenza. Men and older adults are at particular risk for ICU hospitalization. The high prevalence of influenza A and cases of SARS-CoV-2 co-infection also highlight the importance of accurate diagnosis and appropriate treatment. Given the increased risk of infection and disease severity among the elderly, implementing preventive programs, such as annual influenza and coronavirus disease 2019 (COVID-19) vaccinations, is essential for this group. Additionally, attention to laboratory findings like blood oxygen levels can be effective in the early identification of high-risk patients.

Introduction: Discoloration is one of the most common reasons for replacement of resin composites. The purpose of this study was to compare the color stability of three Methacrylate-based Resin Composites (Filtek Z250, Filtek Z250x, Filtek Z350xt) with Silorane-based Resin Composites (Filtek P90) after Accelerated Artificial Aging (AAA).Materials & Methods: In this in vitro study 56 composite discs were prepared (N=14). CIE L*a*b* parameters of each specimen were measured by a reflectance spectrophotometer after 24h and 384 h of AAA. Then Color change (DE) of each composite was calculated. Data were analyzed by one way ANOVA, Tukey and paired t-test at the significance level of 0.05.Results: DE values of Filtek Z250, Filtek Z250x, Filtek Z350xt and Filtek P90 were 7.77, 5.86, 8.95 and 8, respectively. One way ANOVA demonstrated a significant difference between DE values of composites (P˂0.001). Tukey’s test revealed that DE value of Filtek Z250xt was significantly lower than those of other composites (P˂0.05).Conclusion: Silorane and methacrylate based composites showed a color change more than the clinically acceptable level (DE˃3.3) after AAA. Filtek Z250xt showed the lowest color change and other composites showed relatively similar color change.

Background: Due to the occurrence of respiratory failure in patients with COVID-19, the need to use mechanical ventilation to save the lives of patients and improve the clinical conditions of patients hospitalized in the intensive care unit has also become common. In this study, SIMV and PRVC modes of mechanical ventilation have been compared and analyzed on hemodynamics parameters and oxygenation of COVID-19 patients hospitalized in the intensive care unit. Methods: In this study, which was conducted using the time series method, there were patients with COVID-19, who were admitted and treated for respiratory failure in the special care department of Al-Zahra Educational-Treatment Centers from January 1, 2019, to the end of June 1400 AH. They were under mechanical ventilation in one of the two groups with one of the modalities of PRVC, SIMV. Patients underwent periodic visits and were followed up for 48 hours after intubation. Findings: The obtained results show that the hemodynamic stability and oxygenation parameters in PRVC mode are higher than in SIMV mode, while the complications of SIMV mechanical breathing mode show higher values compared to PRVC mode. Conclusion: Hemodynamic parameters in patients with severe respiratory symptoms with COVID-19 who were admitted to the intensive care unit and were under mechanical ventilation with PRVC mode were more stable compared to the SIMV group. The frequency distribution of complications of mechanical ventilation in the SIMV group was significantly higher than in the PRVC group.