BACKGROUND: Following the announcement of the World Health Organization (WHO) on January 30, 2020, of coronavirus disease (COVID)-19 as a global and emergency state of international health emergency; posing a serious threat to the physical health and lives of individuals transmitted through respiratory droplets and close contact. The virus causes respiratory symptoms and damages to other organs, sometimes leading to death in case of exacerbation of symptoms. AIM: This study was conducted through reviewing various articles related to COVID-19 disease, with the purpose of reviewing the epidemiology, prevention and control strategies of COVID-19 coronavirus in Iran. METHODS: In the present review study, the articles indexing in the Persian and Latin databases of SID, Magiran, PubMed, Scopus, Scholar, Web of Science, Embase, MedRxiv, and WHO were examined based on MESH keywords. Finally, 38 articles, 5 protocols and reports were reviewed. RESULTS: According to the report of the WHO on July 22, 2020, 14,765,256 people worldwide have been infected and 612,054 people have died of this virus. Moreover, in Iran, according to the WHO report, 278,827 people were infected and 14,634 people died of the virus until July 22, 2020. Respiratory droplets are the main way of transmission and it can also be transmitted through close contact. According to research, 51% of patients with chronic disease show symptoms such as fever (83%), cough (82%), shortness of breath (31%), muscle pain (11%), fatigue (9%), headache (8%), sore throat (5%), had rhinorrhea (4%), chest pain (2%), diarrhea (2%), and nausea and vomiting (1%). There is currently no specific antiviral treatment or vaccine for severe acute respiratory syndrome coronavirus 2, and clinical treatment for COVID-19 has so far been limited to prophylaxis and palliative care. Quarantine alone is not enough to prevent the spread of COVID-19. Basic health measurements to prevent the spread of the disease include frequent handwashing and the use of personal protective equipment such as masks. CONCLUSION: Extensive research can be the key to solve the existing challenges in the prevention, control, diagnosis, and treatment of the disease. The best ways to fight the new corona disease include educating the people, providing accurate information, providing personal protective equipment, canceling meetings and emphasizing citizens homeliving and regular handwashing, observing social distancing, and finally identifying suspicious cases and quarantine.
Cellulose nanofibrils (CNF) have been explored as an emerging naturally sourced material for use in the preparation of new biomaterials. CNF fibrils have a high aspect ratio with fibril lengths of ~ 1 µm and diameters of 20–40 nm. The assembly of CNF impacts both bulk mechanical properties as well as localized cellular interaction. The ability to reproducibly tune CNF fiber alignment is an active area of CNF-based biomaterial research. Here, we present a simple CNF fibril alignment strategy based on application of constant unilateral force on thin CNF films drying on a flexible substrate. CNF fibril alignment/orientation was characterized using both Polarized Light Microscopy (PLM) and conventional Scanning Electron Microscopy (SEM) approaches. CNF is optically birefringent; therefore, calculation of the birefringence orientation index (BOI) can infer the extent of CNF fibril alignment with a non-destructive, cost-effective technique. CNF fibril alignment is markedly increased with application of 10.2 N force as assessed by both SEM and PLM analysis. SEM imaging resolved individual CNF and the alignment was analyzed using OrientationJ, an ImageJ plugin, to extract fibril angle whereas PLM microscopy provided a BOI value. Both the fibril alignment and BOI score were in agreement; therefore, it is acceptable to infer fibril organization with PLM techniques. Furthermore, the addition of nanoparticle hydroxyapatite did not diminish the CNF fibril alignment as assessed by both PLM and SEM highlighting the utility of the CNF film fabrication technique. In summary, the application of unilateral force on thin CNF films adhered to latex, is an elegant, scalable, and cost-effective technique for generating CNF films with reproducible fibril alignment.
Cellulose nanofibrils (CNFs) have been explored as an emerging naturally sourced material for the development of new biomaterials. The ability to reproducibly tune CNF fiber alignment is an active area of CNF-based biomaterial research. Typically, CNF-based biomaterials are composites, requiring the ability to control the organization of both CNF and additional additives to achieve desired mechanical and cellular interactions. Here, we present a simple CNF fibril alignment strategy based on the application of constant unilateral force on thin CNF films drying on a flexible substrate to reproducibly modulate CNF fibril alignment while integrating nanoparticle hydroxyapatite, a candidate mineral oxide. CNF fibril alignment/orientation is characterized using Polarized Light Microscopy (PLM), Scanning Electron Microscopy (SEM) and mechanical tensile testing. Collectively, all these characterization tools demonstrate that the application of a 10.2 N unilateral force on a CNF film drying on a flexible substrate results in increased CNF fibril alignment. Furthermore, the addition of nanoparticle hydroxyapatite did not diminish the CNF fibril alignment as assessed by both PLM, SEM, and modulus of elasticity highlighting the utility of the CNF film fabrication technique. In summary, the application of unilateral force on thin CNF films adhered to latex is an elegant, scalable, and cost-effective technique for generating CNF composite films with reproducible fibril alignment.
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