Researcher:
Topçu, Ahmet Umur

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Undergraduate Student

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Ahmet Umur

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Topçu

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Topçu, Ahmet Umur

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2022 - 20232

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    Vibrational spectra, force constants and quantum chemical calculations of mu-1,3-azide bridged triphenylphosphine complexes of copper(I) and silver (I)
    (Elsevier, 2022) Güven, Gökçe; Afyon, Semih; Yılmaz, Ayberk; Bölükbaşı, Olcay; N/A; Department of Chemistry; Topçu, Ahmet Umur; Somer, Mehmet Suat; N/A; Faculty Member; Department of Chemistry; N/A; College of Sciences; N/A; 178882
    The dimeric title compounds [(C6H5)(3)P]Cu-2(N-3)(2) and [C6H5)(3)P]Ag-2(N-3)(2) were synthesized and characterized by FT-Raman and IR spectroscopy. The two phases were not isotypic but possessed approximately the same molecular symmetry which was C-2/2m. The assignment of the modes was supported by quantum chemical DFT calculations coupled with TED (Total Energy Distribution) analyses. The calculated (N-N) force constants for the bridging -(NNN)- groups were directly comparable (f(N-N) = 11.75 (Cu) and 12.19 N cm(-1)(Ag)) and harmonized well with those of the free azide anion in the binary alkali azides. The (N-N) bond orders were obtained based on the calculated force constants (Siebert Bond Order, SBO) and Density-dependent electrostatic and chemical (DDEC6) method yielding SBO = 1.92 (Cu) and 1.96 (Ag) and BO = 2.00 (Cu) and 2.03 (Ag), respectively, indicating the presence of double bonds. The results underlined that the (N-N) force constants and bond orders in the bridging azide units were practically unaffected by the nature of the central metal atoms and that they could be regarded as quasi isolated anions similar to those in the binary azide compounds.
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    COVID-19–associated mucormycosis: a systematic review and meta-analysis of 958 cases
    (Elsevier, 2023) Khostelidi, Sofya N.; Klimko, Nikolai; Cornely, Oliver; Zakhour, Johnny; Kanj, Souha S.; Seidel, Danila; Hoenigl, Martin; N/A; Özbek, Laşin; Topçu, Ahmet Umur; Manay, Mehtap; Esen, Buğra Han; Bektaş, Şevval Nur; Aydın, Serhat; Özdemir, Barış; Ergönül, Önder; Undergraduate Student; Undergraduate Student; Undergraduate Student; Undergraduate Student; Undergraduate Student; Undergraduate Student; Undergraduate Student; Faculty Member; Koç Üniversitesi İş Bankası Enfeksiyon Hastalıkları Uygulama ve Araştırma Merkezi (EHAM) / Koç University İşbank Center for Infectious Diseases (KU-IS CID); School of Medicine; School of Medicine; School of Medicine; School of Medicine; School of Medicine; School of Medicine; School of Medicine; N/A; N/A; N/A; N/A; N/A; N/A; N/A; 110398
    Background: mucormycosis, a rare fungal infection, has shown an increase in the number of reported cases during the COVID-19 pandemic. Objectives: to provide a comprehensive insight into the characteristics of COVID-19–associated mucormycosis, through a systematic review and meta-analysis. Methods of data synthesis: demographic information and clinical features were documented for each patient. Logistic regression analysis was used to predict the risk of mortality. Data sources: PubMed, Scopus, Web of Science, Cochrane, CINAHL, Ovid MEDLINE, and FungiSCOPE. Study eligibility criteria: studies reporting individual-level information in patients with adult COVID-19–associated mucormycosis (CAM) between 1 January 2020 and 28 December 2022. Participants: adults who developed mucormycosis during or after COVID-19. Interventions: patients with and without individual clinical variables were compared. Assessment of risk of bias: quality assessment was performed based on the National Institutes of Health quality assessment tool for case series studies. Results: nine hundred fifty-eight individual cases reported from 45 countries were eligible. 88.1% (844/958) were reported from low- or middle-income countries. Corticosteroid use for COVID-19 (78.5%, 619/789) and diabetes (77.9%, 738/948) were common. Diabetic ketoacidosis (p < 0.001), history of malignancy (p < 0.001), underlying pulmonary (p 0.017), or renal disease (p < 0.001), obesity (p < 0.001), hypertension (p 0.040), age (>65 years) (p 0.001), Aspergillus coinfection (p 0.037), and tocilizumab use during COVID-19 (p 0.018) increased the mortality. CAM occurred on an average of 22 days after COVID-19 and 8 days after hospitalization. Diagnosis of mucormycosis in patients with Aspergillus coinfection and pulmonary mucormycosis was made on average 15.4 days (range, 0–35 days) and 14.0 days (range, 0–53 days) after hospitalization, respectively. Cutaneous mucormycosis accounted for <1% of the cases. The overall mortality rate was 38.9% (303/780). Conclusion: mortality of CAM was high, and most reports were from low- or middle-income countries. We detected novel risk factors for CAM, such as older age, specific comorbidities, Aspergillus coinfection, and tocilizumab use, in addition to the previously identified factors.