Analysis of post-COVID symptoms and predisposing factors for chronic post-COVID syndrome.

Introduction: While there is sufficient information about acute COVID-19, which can cause a multisystemic and fatal disease, post-COVID syndrome and risk factors for this condition remain poorly known. We aimed to identify postCOVID symptoms and risk factors for chronic post-COVID syndrome through this study. Materials and Methods: This prospective cross-sectional study was conducted on 254 out of 384 COVID-19 patients admitted to our COVID-19 polyclinic between February and April 2021. The patients were questioned with a list of 37 symptoms at the fifth and twelfth weeks after disease onset via phone review, and their acute post-COVID (APC) and chronic post-COVID (CPC) symptoms were recorded. Data on risk factors were collected from the hospital's medical records system. Associations between symptom count in the CPC phase and age, sex, hospitalization, RT-PCR result, specific radiological findings, comorbidities, and long-term medications were evaluated. Result: Two hundred twenty-one patients had APC symptoms, and 138 patients had CPC symptoms. While the most common symptom was fatigue at week five, it was hair loss at week 12. Symptoms were observed significantly less in the CPC phase than in the APC phase (Z= -12.301, p= 0.00). Female sex and the presence of specific radiological findings were significantly associated with the occurrence of CPC symptoms (p= 0.03, p= 0.00, respectively). Long-term use of angiotensin-2 receptor blockers (ARBs) was correlated with a low symptom count in the CPC phase (p= 0.00). Conclusions: Female sex and the presence of specific radiological findings were risk factors for developing CPC. Long-term use of ARBs was associated with a low chronic post-COVID symptom burden. A substantial cluster of multisystemic symptoms was observed in both phases, and this condition highlights the requirement for customized outpatient management that includes long-term follow-up and treatment of COVID-19 patients. Identifying the high-risk patients that will develop persistent symptoms can guide this management.

Speciation of chromium in water samples by solid-phase extraction on a new synthesized adsorbent.

Poly(1,3-thiazol-2-yl methacrylamide-co-4-vinyl pyridine-co-divinylbenzene) was prepared and used as a sorbent for the solid-phase extraction of Cr(VI) ions from aqueous solution. Two forms of chromium showed different exchange capacities at different pH values; Cr(VI) was selectively retained especially at pH 2. The total chromium was determined after the oxidization of Cr(III) to Cr(VI) by potassium permanganate as an oxidizing agent. Then, Cr(III) was calculated by subtracting the Cr(VI) concentration from the total chromium concentration. The optimum conditions were found for species of Cr(VI) (pH 2; eluent, 4 mol L(-1) NH3; sample flow rates, 2 mL min(-1) and eluent flow rates, 1 mL min(-1) etc.). The adsorption capacity and binding equilibrium constant were calculated to be 80.0 mg g(-1) and 0.018 L mg(-1), respectively. A preconcentration factor of 30 and a three-sigma detection limit of 2.4 µg L(-1) (n = 20) were achieved for Cr(VI) ions. The developed method was applied to stream water and waste water samples. At the same time, the polymer was applied to a certified reference material (CRM) (TMDA-52.3) sample.