Novel coronavirus disease 2019 (COVID-19) has resulted in a global pandemic and is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Several studies have suggested that a precise disulfide-thiol balance is crucial for viral entry and fusion into the host cell and that oxidative stress generated from free radicals can affect this balance. Here, we reviewed the current knowledge about the role of oxidative stress on SARS-CoV and SARS-CoV-2 infections. We focused on the impact of antioxidants, like NADPH and glutathione, and redox proteins, such as thioredoxin and protein disulfide isomerase, that maintain the disulfide-thiol balance in the cell. The possible influence of these biomolecules on the binding of viral protein with the host cell angiotensin-converting enzyme II receptor protein as well as on the severity of COVID-19 infection was discussed.
Ethyl formate is very effective for the formylation of amines and diamines to yield formamides and diformamides, respectively. Subsequent dehydrogenation of 1:1 mixtures of formamides and amines or diformamides and diamines with ruthenium pincer catalysts furnishes ureas and polyureas, respectively. This approach provides access to a large structural variety of ureas and polyureas because a wide range of primary amines and diamines are readily converted to the corresponding ureas and polyureas. Small molecule ureas were isolated in yields of up to 95%, whereas polyureas were isolated in lower yields (up to 68%) due to strong adhesion to the reaction flask and poor solubility impeding product removal. Furthermore, the ease with which hydrogen can be removed from the reaction medium enables the synthesis of polyureas with molecular weights that are among the highest reported to date (M n up to 31,100 g mol À1 ). Notably, this synthetic approach does not necessitate high pressure conditions, simplifying equipment needed for their preparation, and it avoids the use of isocyanates, which have significant health concerns.
Enzymes play important roles in many biological processes. Amino acid residues in the active site pocket of an enzyme, which are in direct contact with the substrate(s), are generally believed to be critical for substrate recognition and catalysis. Identifying and understanding how these "catalytic" residues help enzymes achieve enormous rate enhancement has been the focus of many structural and biochemical studies over the past several decades. Recent studies have shown that enzymes are intrinsically dynamic and dynamic coupling between distant structural elements is essential for effective catalysis in modular enzymes. Therefore, distal residues are expected to have impacts on enzyme function. However, few studies have investigated the role of distal residues on enzymatic catalysis. In the present study, effects of distal residue mutations on the catalytic function of an aminoacyl-tRNA synthetase, namely, prolyl-tRNA synthase, were investigated. The present study demonstrates that distal residues significantly contribute to catalysis of the modular Escherichia coli prolyl-tRNA synthetase by maintaining intrinsic protein flexibility.
Copolymerizing glutaraldehyde with tetraols such as diglycerol, meso‐erythritol, and pentaerythritol is particularly effective for forming very high molecular weight polycycloacetals (Mn up to 65,000 g/mol) with elastomeric properties and up to 70% biorenewable content by weight. Altering the tetraol monomer feed ratio provides control over the polycycloacetal's tensile properties. The polymerizations are high‐yielding, readily scalable, and employ commercially available starting materials that are used without further purification. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48780.
Chemotherapy can be challenging and overwhelming for patients, but when patients are knowledgeable about chemotherapy, their comfort level, overall satisfaction, and coping improve. It is currently unknown whether patients prefer information about chemotherapy to be provided by specific care team members and whether demographic characteristics affect learning preferences. We developed a 31-question questionnaire that asked patients when chemotherapy information was discussed and who they wanted that information to come from. The questionnaire was given to 50 patients who had completed 1 cycle of chemotherapy. Patients were evenly distributed among age categories of 45 to 64 years, 65 to 74 years, and 75 years or older. Thirty participants (60%) were women, 33 (66%) had high school degrees, and 23 (46%) were receiving their first chemotherapy regimen. Sixty percent of patients best understood goals of care from oncologists, 70% wanted goals of care to come from oncologists, and 61% best understood and wanted to understand logistics of chemotherapy from oncologists. Sixty-six percent of patients understood adverse effects when they were explained by nursing staff, and 56% wanted explanations of adverse effects to come from nursing staff. Patients did not prefer a specific care team member or information source when receiving financial cost information. Patients often preferred to receive chemotherapy information from their oncologist; however, other members of the care team also provided information to patients in a way that was understood.
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