In the present study, phosphoric acid doped polybenzimidazole (PBI) membranes with potential applications in high temperature PEM fuel cells were investigated. PBI was synthesized by polycondensation of 3,3 0 -diaminobenzidine and isophtalic acid in polyphosphoric acid. The formation of PBI was validated by H 1 -NMR and elemental analysis. PBI membranes were prepared by solution casting method and immersed in phosphoric acid in order to provide ionic conductivity. The phosphoric acid doped membranes were used to prepare membrane electrode assemblies (MEA) for PEMFC operation. Gas diffusion layer (GDL) spraying method was used to prepare the electrodes. In order to determine optimum electrode structure, the effect of electrode preparation technique on fuel cell performances was studied. Two methods were applied in which the binder differs in the catalyst ink. In the first method, 5 wt % PBI solution was used as the binder. In the second method, polyvinylidene fluoride (PVDF) was used in addition to PBI as the binder in the catalyst ink. The MEA were tested in a single cell operating at 100 C without need for humidification of reactant gases. The observed maximum power output was increased considerably from 0.015 to 0.072 W/cm 2 at 150 C when the binder of the catalyst was changed from PBI to PBI and PVDF mixture (PVDF : PBI ¼ 3 : 1). A single cell was operated up to 160 C and the power outputs of 0.032 and 0.063 W/cm 2 were obtained at operating temperatures of 125 and 160 C, respectively.
Objectives: To explore the rate of pneumoconiosis in dental technicians (DTP) and to evaluate the risk factors. Material and Methods: Data of 893 dental technicians, who were admitted to our hospital in the period January 2007-May 2012, from 170 dental laboratories were retrospectively examined. Demographic data, respiratory symptoms, smoking status, work duration, working fields, exposure to sandblasting, physical examination findings, chest radiographs, pulmonary function tests and high-resolution computed tomography results were evaluated. Results: Dental technicians' pneumoconiosis rate was 10.1% among 893 cases. The disease was more common among males and in those exposed to sandblasting who had 77-fold higher risk of DTP. The highest profusion subcategory was 3/+ (according to the International Labour Organization (ILO) 2011 standards) and the large opacity rate was 13.3%. Conclusions: To the best of our knowledge, it was the largest DTP case series (N = 893/90) in the literature in English. Health screenings should be performed regularly for the early diagnosis of pneumoconiosis, which is an important occupational disease for dental technicians.
The aim of this study was to explain the demographic data, comorbidity and laboratory fi ndings of our fi rst cases in COVID-19 pneumonia in our country. METHODS: We gathered the data of COVID-19 pneumonia participants from our electronic medical system, including daily medical knowledge and laboratory, radiological, and microbiological results between March 10 to April 7, 2020. RESULTS: Totally, 125 patients, whose fi ndings were compatible with COVID-19, were included in the study, 42 patients were excluded from the study. The distribution of genders was, 39 females (46.9 %), 44 males (53.01 %), the average age was 56. 36 ± 16.25 (19-85). Hypertension above 60 years of age and diabetes mellitus under 60 years of age were the most common comorbidities. Neutrophils/ Lymphocyte percent (% NLR) was noted in 44 (53.01 %) patients, average: 3 (range 1.78-4.63). There was a statistically signifi cant and positive relationship between D-dimer and C Reactive Protein (CRP) and ferritin. CONCLUSION: We detected that comorbidities, which were seen at COVID-19 disease differ according to the patients age. Besides that D-dimer, ferritin and CRP outcomes were particularly high and had a signifi cant correlation with COVID-19 severity (Tab. 3, Fig. 2, Ref. 25).
Objective We aimed to evaluate the relationship between perceived social support, coping strategies, anxiety, and depression symptoms among hospitalized COVID-19 patients by comparing them with a matched control group in terms of age, gender, and education level. Method The patient group (n = 84) and the healthy controls (HCs, n = 92) filled in the questionnaire including the socio-demographic form, Hospital Anxiety Depression Scale, Multidimensional Perceived Social Support Scale, and Brief Coping Orientation to Problems Experienced through the online survey link. Results The COVID-19 patients had higher perceived social support and coping strategies scores than the HCs. However, anxiety and depression scores did not differ significantly between the two groups. In logistic regression analysis performed in COVID-19 patients, the presence of chest CT finding (OR = 4.31; 95% CI = 1.04–17.95) was a risk factor for anxiety and the use of adaptive coping strategies (OR = 0.86; 95% CI = 0.73–0.99) had a negative association with anxiety. In addition, the use of adaptive coping strategies (OR = 0.89; 95% CI = 0.79–0.98) and high perceived social support (OR = 0.97; 95% CI = 0.93– 0,99) had a negative association with depression symptoms. Conclusions Longitudinal studies involving the return to normality phase of the COVID-19 pandemic are needed to investigate the effects of factors such as coping strategies and perceived social support that could increase the psychological adjustment and resilience of individuals on anxiety and depression.
Life-threatening ‘breakthrough’ cases of critical COVID-19 are attributed to poor or waning antibody response to the SARS-CoV-2 vaccine in individuals already at risk. Pre-existing autoantibodies (auto-Abs) neutralizing type I IFNs underlie at least 15% of critical COVID-19 pneumonia cases in unvaccinated individuals; however, their contribution to hypoxemic breakthrough cases in vaccinated people remains unknown. Here, we studied a cohort of 48 individuals (age 20-86 years) who received 2 doses of an mRNA vaccine and developed a breakthrough infection with hypoxemic COVID-19 pneumonia 2 weeks to 4 months later. Antibody levels to the vaccine, neutralization of the virus, and auto-Abs to type I IFNs were measured in the plasma. Forty-two individuals had no known deficiency of B cell immunity and a normal antibody response to the vaccine. Among them, ten (24%) had auto-Abs neutralizing type I IFNs (aged 43-86 years). Eight of these ten patients had auto-Abs neutralizing both IFN-α2 and IFN-ω, while two neutralized IFN-ω only. No patient neutralized IFN-β. Seven neutralized 10 ng/mL of type I IFNs, and three 100 pg/mL only. Seven patients neutralized SARS-CoV-2 D614G and the Delta variant (B.1.617.2) efficiently, while one patient neutralized Delta slightly less efficiently. Two of the three patients neutralizing only 100 pg/mL of type I IFNs neutralized both D61G and Delta less efficiently. Despite two mRNA vaccine inoculations and the presence of circulating antibodies capable of neutralizing SARS-CoV-2, auto-Abs neutralizing type I IFNs may underlie a significant proportion of hypoxemic COVID-19 pneumonia cases, highlighting the importance of this particularly vulnerable population.
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