The anchoring of a Cu(ii)–salophen complex on magnetic mesoporous cellulose nanofibers: green synthesis and an investigation of its catalytic role in tetrazole reactions through a facile one-pot route

Today, most synthetic methods are aimed at carrying out reactions under more efficient conditions and the realization of the twelve principles of green chemistry. Due to the importance and widespread applications of tetrazoles in various industries, especially in the field of pharmaceutical chemistry, and the expansion of the use of nanocatalysts in the preparation of valuable chemical reaction products, we decided to use an (Fe₃O₄@NFC@NSalophCu)CO₂H nanocatalyst in this project. In this study, the synthesis of the nanocatalyst (Fe₃O₄@NFC@NSalophCu)CO₂H was explained in a step-by-step manner. Confirmation of the structure was obtained based on FT-IR, EDX, FE-SEM, TEM, XRD, VSM, DLS, TGA, H-NMR, and CHNO analyses. The catalyst was applied to the synthesis of 5-substituted-1H-tetrazole and 1-substituted-1H-tetrazole derivatives through multi-component reactions (MCRs), and the performance was assessed. With advances in science and technology and increasing environmental pollution, the use of reagents and methods that are less dangerous for the environment has received much attention. Therefore, following green chemistry principles, with the help of the (Fe₃O₄@NFC@NSalophCu)CO₂H salen complex as a nanocatalyst that is recyclable, cheap, safe, and available, the use of water as a green solvent, and reduced reaction times, the synthesis of tetrazoles can be achieved.

Due to the importance and widespread applications of tetrazoles, especially in pharmaceutical chemistry, and the expansion of the use of nanocatalysts in the preparation of valuable chemical reaction products, we decided to use a (Fe₃O₄@NFC@NSalophCu)CO₂H nanocatalyst.     

Significance of abnormal myocardial perfusion scintigraphy in young adult patients with SLE

Objectives  

Detection of subclinical coronary artery disease (CAD) is a potential challenge in patients with systemic lupus erythematosus (SLE) and it is suggested that myocardial perfusion single photon emission computerized tomography (SPECT) is more sensitive than exercise test in this setting. However, the significance of perfusion abnormalities in SLE patients is not well known. In this study, we evaluated the prognostic significance of myocardial perfusion defects in patients with SLE.     

Introduction of a trinuclear manganese(iii) catalyst on the surface of magnetic cellulose as an eco-benign,efficient and reusable novel heterogeneous catalyst for the multi-component synthesis of new derivatives of xanthene

In this work, the new trinuclear manganese catalyst defined as Fe₃O₄@NFC@NNSM-Mn(iii) was successfully manufactured and fully characterized by different techniques, including FT-IR, XRD, TEM, SEM, EDX, VSM, and ICP analysis. There have been reports of the use of magnetic catalysts for the synthesis of xanthine derivatives. The critical potential interest in the present method include short reaction time, high yields, recyclability of the catalyst, easy workup, and the ability to sustain a variety of functional groups, which give economical as well as ecological rewards. Also, the synthesized catalyst was used as a recyclable trinuclear catalyst in alcohol oxidation reactions at 40 °C. The magnetic catalyst activity of Fe₃O₄@NFC@NNSM-Mn(iii) could be attributed to the synergistic effects of the catalyst Fe₃O₄@NFC@NNS-Mn(iii) with melamine. Employing a sustainable and safe low temperature, using an eco-friendly solvent, no need to use any additive, and long-term stability and magnetic recyclability of the catalyst for at least six successive runs are the advantages of the current protocol towards green chemistry. This protocol is a benign, environmentally friendly method for heterocycle synthesis.

In this work, the new trinuclear manganese catalyst defined as Fe₃O₄@NFC@NNSM-Mn(iii) was successfully manufactured and fully characterized by different techniques, including FT-IR, XRD, TEM, SEM, EDX, VSM, and ICP analysis.     

Epidemiological,imaging, laboratory,and clinical characteristics and factors related to mortality in patients with COVID-19: a single-center study

ObjectivesCoronavirus disease 2019 (COVID-19) is a novel pandemic. Considerable differences in disease severity and the mortality rate have been observed in different parts of the world. The present study investigated the characteristics and outcomes of patients hospitalized with COVID-19 in Iran.MethodsWe established a retrospective cohort to study hospitalized COVID-19 patients in Iran. Epidemiological, imaging, laboratory, and clinical characteristics and outcomes were recorded from medical documents. The chi-square test, t-test, and logistic regression models were used to analyze the data. A p<0.05 was considered to indicate statistical significance.ResultsIn total, 364 cases (207 males and 157 females) were analyzed. The most common symptoms were cough, fever, and dyspnea. Multifocal bilateral ground-glass opacities with peripheral distribution were the predominant imaging finding. The mean age of patients was 54.28±18.81 years. The mean age of patients who died was 71.50±14.60 years. The mortality rate was 17.6%. The total proportion of patients with a comorbidity was 47.5%, and 84.4% of patients who died had a comorbidity. Sex, history of diabetes mellitus, and dyslipidemia were not significantly associated with mortality (p>0.05). However, mortality showed significant relationships with body mass index; age; history of hypertension, chronic kidney disease (CKD), ischemic heart disease, cerebrovascular accident (CVA), pulmonary disease, and cancer; and abnormal high-resolution computed tomography (HRCT) findings (p<0.05 for all). Cancer had the highest odds ratio.ConclusionComorbidities (especially cancer, CKD, and CVA), severe obesity, old age, and abnormal HRCT findings affected the health outcomes of patients hospitalized with COVID-19.     

Macular vessel density reduction in patients recovered from COVID-19: a longitudinal optical coherence tomography angiography study

Graefe's Archive for Clinical and Experimental Ophthalmology - To quantify the longitudinal changes of the macular microvasculature and the foveal avascular zone (FAZ) parameters in patients...     

Prevalence of Hepatitis D Virus Infection Among Patients With Chronic Hepatitis B Attending Birjand Hepatitis Clinic (East of Iran) in 2012

Background

Hepatitis delta virus (HDV) is a defective RNA virus dependent on Hepatitis B virus (HBV) infection for its replication and expression. All patients with HBV infection should be tested for the presence of HDV infection. It is estimated that approximately 5% of hepatitis B surface antigen (HbsAg) carriers in the world are HDV infected patients. HBV-HDV co-infection may lead to more severe acute disease and higher risks of fulminant hepatitis, cirrhosis, and hepatocellular carcinoma than those having HBV infection alone. Also, HBV infected patients with HDV super-infection have a higher rate of progression to chronic disease and serious complications.

Objectives

Our aim was to determine the prevalence of HDV infection among chronic hepatitis B (CHB) patients attending Birjand Hepatitis Clinic, East of Iran.

Materials and Methods

A cross-sectional analytical study was conducted on 413 CHB patients in 2012. Serology test for anti-HDV was measured by ELISA in these patients. CHB patients had positive hepatitis B surface antigen for at least 6 months before the study entrance.

Results

The mean age of CHB patients was 38.5± 11.9 years and 55.9% of them (231 patients) were male. There were 13 cases (3.1%) with HDV infection. There was no association between positive anti-HDV serology and factors such as age, gender, carrier state, liver enzymes, and positive hepatitis B e antigen (HBeAg) serology.

Conclusions

Although HDV had a low prevalence in our area, it is important for healthcare providers and policy makers to plan preventive strategies for HDV spread as well as HBV prevention programs among high risk population.     

Synthesis,characterization and cytotoxicity evaluation of a novel magnetic nanocomposite with iron oxide deposited on cellulose nanofibers with nickel (Fe3O4@NFC@ONSM-Ni)

A heterogeneous, magnetically recoverable nanocomposite, Fe₃O₄@NFC@ONSM-Ni(ii) was prepared by immobilization of a novel Ni(ii) Schiff base complex on Fe₃O₄@NFC nanoparticles followed by treatment with melamine. This trinuclear catalyst has been characterized using several analytical techniques including FT-IR, TEM, Fe-SEM, EDX, DLS, ICP, TGA, VSM, and XRD. It was used as an efficient catalyst for one-pot solvent-free synthesis of 1,4-dihydropyridine and poly-hydro quinoline derivatives through Hantzsch reaction. This catalyst showed remarkable advantage over previously reported catalysts due to suitable conditions, short reaction time, high efficiency and lower catalyst load and timely recovery of the magnetic catalyst. Moreover, the effects of Fe₃O₄@NFC@ONSM-Ni(ii) nanoparticles on the in vitro proliferation of human leukemia cell line (k562) and human breast cancer cells (MDA-MB-231) were investigated. The results of MTT and Hochest assays suggested that the nanoparticles could effectively inhibit the proliferation of these cancer cells in a time- and concentration-dependent manner.

A heterogeneous, magnetically recoverable nanocomposite, Fe₃O₄@NFC@ONSM-Ni(ii) was prepared by immobilization of a novel Ni(ii) Schiff base complex on Fe₃O₄@NFC nanoparticles followed by treatment with melamine.     

Novel biocompatible core/shell Fe3O4@NFC@Co(ii) as a new catalyst in a multicomponent reaction: an efficient and sustainable methodology and novel reusable material for one-pot synthesis of 4H-pyran and pyranopyrazole in aqueous media

Today, due to the developing need for inexpensive catalysts, recyclable magnetic nanocatalysts immobilized on polysaccharides possess many advantages over classical heterogeneous catalysts. However, cellulose has been an appealing material in catalysis science and technology. In this work, by controlling the interaction between the inorganic complexes and the support material, we designed a high activity nanostructured combination of a magnetic nanoparticle Fe₃O₄@NFC@Co(ii) terminated complex as a multi-nuclear catalyst. This protocol involves an environment friendly approach using cobalt acetate. The magnetic nanostructure Fe₃O₄@NFC@Co(ii) can be used as a novel, green, and a powerful catalyst that demonstrates a short reaction time, high yield and easy procedure for the cascade Knoevenagel–Michael-cyclocondensation reaction for the one-pot synthesis of 4H-pyrans and pyranopyrazoles. The superparamagnetic nanocomposite could be conveniently separated by using an external magnet. Moreover, the catalyst could be reused at least five times in new reaction runs without a noticeable loss of activity. The prepared catalyst was characterized by FT-IR, XRD, VSM, FESEM, EDAX, TEM, ICP, and TGA techniques. The experiments were achieved with good yields and implied that the catalytic method was effective and convenient for heterocyclic synthesis.

Today, due to the developing need for inexpensive catalysts, recyclable magnetic nanocatalysts immobilized on polysaccharides possess many advantages over classical heterogeneous catalysts.