ABSTRACT
Coronavirus disease 2019 (COVID-19) is a newly emerging human infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Early diagnosis is essential to reducing the transmission rate and mortality of COVID-19. PCR-based tests are the gold standard for the confirmation of COVID-19, but immunological tests for SARS-CoV-2 detection are widely available and play an increasingly important role in the diagnosis of COVID-19. Nanomechanical sensors are biosensors that work based on a change in the mechanical response of the system when a foreign object is added. In this paper, a graphene-based nanoresonator sensor for SARS-CoV-2 detection was introduced and analyzed by using the finite element method (FEM). The sensor was simulated by coating a single-layer graphene sheet (SLGS) with a specific antibody against SARS-CoV-2 Spike S1 antigen. In the following, the SARS-CoV-2 viruses were randomly distributed on the SLGSs, and essential design parameters of the nanoresonator, including frequency shift and relative frequency shift, were evaluated. The effect of the SLGS size, aspect ratio and boundary conditions, antibody concentration, and the number of viruses variation on the frequency shift and relative frequency shift were investigated. The results revealed that, by proper selection of the nanoresonator design variables, a good sensitivity index is achievable for identifying the SARS-CoV-2 virus even when the number of the viruses are less than 10 per test. Eventually, according to the simulation results, by using SLGS geometry determination, an analytical relationship is presented to predict the limit of detection (LOD) of the sensor with the required sensitivity index. The results can be applied in designing and fabricating specific graphene-based nanoresonator sensors for SARS-CoV-2.
ABSTRACT
Genetic divergence and environment influence on speciation process are the great deal studies over recent decades. One of the best ways for exploring the interaction of geography and genetics is the evaluation of hybrids in a contact zone. To understand if there is one or more hybrid zone between house mouse subspecies in Iran and what are the differences comparing these zones with European well-known hybrid zone, we performed this approach. Samples were live-trapped from Ilam city in west for sensu lato M. m. domesticus subspecies, and Neishabur city in north-east of Iran for sensu lato M. m. musculus subspecies. In five experimental groups, male and female mice of the two subspecies were crossed reciprocally to generate F1 hybrids, and then F1 offspring males and females were crossed also reciprocally between siblings to generate F2 hybrids. In the same manner as seen in European hybrid zone, hybridization between female M. m. musculus and male M. m. domesticus of all five groups showed male sterility in F1 generation, but intact female offspring. These sterile males comparing with a parent or healthy males showed low count and more abnormal sperm percentage in morphological and testis histological section studies. Comparing the results from this study with numerous studies carried out during several years on the European hybrid zone showed an equal condition of contact between two subspecies. Genetical elements have kept their same influence on postzygotic reproductive isolation more than environmental effects far from the Europe, here in Iran.
ABSTRACT
Atrial Fibrillation (AF) is the most common cardiac arrhythmia. Generally, the therapeutic options for managing AF include the use of anticoagulant drugs that prevent the coagulation of blood. New Oral Anticoagulants (NOACs) are not optimally prescribed to patients, despite their efficacy. In Canada, NOAC medications are not directly available to patients who belong to provincial benefits programs, rather a NOAC special authorization process establishes the eligibility of a patient to receive a NOAC and be paid by the provincial Pharmacare program. This special authorization process is tedious and paper-based which inhibits physicians to prescribe NOAC leading to suboptimal AF care to patients. In this paper, we present a computerized NOAC Authorization Decision Support System (NOAC-ADSS), accessible to physicians to help them (a) determine a patient eligibility for NOAC based on Canadian AF clinical guidelines, and (b) complete the special authorization form. We present a semantic web based system to ontologically model the NOAC eligibility criteria and execute the knowledge to determine a patient NOAC eligibility and dosage.
