RESUMEN
Ab initio techniques have been used to investigate structural changes in semiconducting Mg2Si and Ca2Si thin films (from 17 nm down to 0.2 nm corresponding to the 2D structure) along with band-gap variations due to quantum confinement. Cubic Mg2Si(111) thin films being dynamically stable at thicknesses (d) larger than 0.3 nm displayed an indirect band gap, the reduction of which with increasing d could be reasonably well described by the simple effective mass approximation. Only 2D Mg2Si has a unique structure because of the orthorhombic distortion and the direct band gap. Since the surface energy of cubic Ca2Si(111) films was lower with respect to any surface of the orthorhombic phase, which is the ground state for the Ca2Si bulk, the metastable in-bulk cubic phase in the form of thin films turned out to be preferable in total energy than any orthorhombic Ca2Si thin film for d < 3 nm. Sizable structural distortion and the appearance of surface states in the gap region of Ca2Si thin films with d < 3 nm could be the reason for an odd dependence of the band-gap variation on d.
RESUMEN
The SARS-CoV-2 pandemic has shown how serious the problem of re-emerging zoonotic infections is for our existence. Migrations of animals, which are natural reservoirs of a particular virus, play a colossal role in the spread of pathogens to new territories. Examples are the migrations of both land animals (carnivores, rodents, and ungulates) and many marine mammals (pinnipeds and cetaceans). Yet the most interesting from the point of view of the speed and range of the spread of viral infections are migrations associated with flights. In nature, these can be migrations of insects, bats, and, of course, birds. Unfortunately, there are very few studies on the migration of these animals in Russia. Considering the problems related to climate change and other environmental factors, it is important to obtain up-to-date data on the changing animal migration routes and, as a consequence, to develop domestic equipment, particularly transmitters, to fix them.
RESUMEN
We investigated the incidence of 15 respiratory viruses among 2991 children with acute respiratory infections in Novosibirsk city, Russia, prior to the COVID-19 pandemic (2013-2020). Viral infections were detected in 72.5% cases. The incidence of human coronavirus was 2% (Alphacoronaviruses, 63%; Betacoronaviruses, 37%).
Asunto(s)
COVID-19 , Infecciones del Sistema Respiratorio , COVID-19/epidemiología , Niño , Niño Hospitalizado , Hospitalización , Humanos , Incidencia , Pandemias , Infecciones del Sistema Respiratorio/epidemiología , SARS-CoV-2RESUMEN
Different methods for producing bulk quantities of concentrated and purified SARS-CoV-2 for the use as antigens and for the research into COVID-19 biology were tested.
Asunto(s)
Prueba de COVID-19/métodos , COVID-19/diagnóstico , SARS-CoV-2/inmunología , Carga Viral/inmunología , Virión/inmunología , Animales , Anticuerpos Neutralizantes/aislamiento & purificación , Anticuerpos Neutralizantes/metabolismo , Anticuerpos Antivirales/aislamiento & purificación , Anticuerpos Antivirales/metabolismo , COVID-19/virología , Línea Celular , Chlorocebus aethiops , Convalecencia , Células Epiteliales/virología , Humanos , Sueros Inmunes/química , SARS-CoV-2/genética , SARS-CoV-2/crecimiento & desarrollo , Porcinos , Células Vero , Carga Viral/genética , Proteínas Virales/inmunología , Proteínas Virales/aislamiento & purificación , Proteínas Virales/metabolismo , Virión/genética , Virión/crecimiento & desarrollo , Replicación ViralRESUMEN
Antiviral efficiency of oxidized dextrans (OD) with different molecular weights and oxidation degree (OD40min, OD70min, OD40max, and OD70 max) was studied in vitro and in vivo. Dextrans OD40max and OD70max prevented the development of the cytopathic effect of influenza A(H1N1)pdm09 virus in more than 50% MDCK cells vs. control (no OD). Four intranasal doses of OD40min, OD40max, and OD70min and one intranasal dose of OD70max before infection of BALB/c mice with A(H1N1)pdm09 influenza virus significantly reduced mortality and prolonged life span in comparison with controls receiving saline. These and our previous data attest to clear-cut preventive effect of OD in influenza infection.
Asunto(s)
Antivirales/farmacología , Dextranos/farmacología , Subtipo H1N1 del Virus de la Influenza A/efectos de los fármacos , Infecciones por Orthomyxoviridae/prevención & control , Animales , Antivirales/uso terapéutico , Dextranos/química , Dextranos/uso terapéutico , Perros , Femenino , Células de Riñón Canino Madin Darby , Masculino , Ratones , Ratones Endogámicos BALB C/anomalías , Oxidación-ReducciónRESUMEN
Here we compare the results of pathological and virological examinations of mice experimentally infected with either wild-type or mouse-adapted pandemic A(H1N1) pdm09 viruses and highly pathogenic avian influenza (HPAI) virus A(H5N1). Mice were sacrificed on days 1, 3, 6, and 10 post infection or whenever morbidity was severe enough to justify euthanasia. Morbidity rates were calculated on the basis of clinical signs (weight loss, poor hair coat, hunched posture and paresis); virus-induced disease was characterised by the histopathology of lung; virus dissemination was determined by virus isolation on organ samples of lung, brain, liver, kidney and spleen. All mice infected with mouse-adapted A(H1N1) pdm09 died in the course of the experiment, whereas 20% of animals survived the infection with A(H5N1). Echinocyte formation changed the rheological properties of blood in animals infected with either mouse-adapted A(H1N1) pdm09 or A(H5N1). To sum up, the adaptation of pandemic A(H1N1) pdm09 virus can confer an enhanced virulence similar to or even exceeding that of HPAI A(H5N1) virus.
Asunto(s)
Subtipo H1N1 del Virus de la Influenza A/patogenicidad , Subtipo H5N1 del Virus de la Influenza A/patogenicidad , Infecciones por Orthomyxoviridae/patología , Infecciones por Orthomyxoviridae/virología , Adaptación Biológica , Animales , Pulmón/patología , Masculino , Ratones , Ratones Endogámicos BALB C , Virulencia , Esparcimiento de VirusRESUMEN
Serological detection of some pathogens in the beluga whale Delphinapterus leucas population from Sakhalinsky Bay of the Sea of Okhotsk (Sakhalin-Amur beluga whale stock) was performed in 2013-2014 after the largest recorded flood of the Amur River (among observations since 1896). The percent of this population that is immune to the causative agents of clonorchosis was 25.6%; toxoplasmosis, 11.5%; brucellosis, 38.5%; tuberculosis, 30.8%; cetacean morbillivirus infection, 16.7%; and to alpha and gamma herpes viruses each, 21.8%.
RESUMEN
Analysed herein are the results of surgical treatment of 55 patients who from June 2013 to August 2014 underwent a total of 56 reconstructive operations on carotid arteries during an acute period of ischaemic stroke. The operations were performed within the terms varying from 24 hours to 18 days after the onset of first symptoms of ischaemic stroke. The neurological status was assesses by the neurologist according to the NIH Stroke Severity Scale (USA) and the Modified Rankin Scale. Prior to operation neurological deficit in 18 patients corresponded to 4 points by the Rankin Scale. Carotid endarterectomy was performed in 55 patients, of these in 24 according to the eversion technique. In 10 patients eversion carotid endarterectomy was performed in combination with ICA resection. One patient was simultaneously subjected to eversion carotid endarterectomy and carotid-subclavian shunting bypass grafting. Carotid endarterectomy with autovenous-patch plasty was performed in 11 patients. Resection of the occluded internal carotid artery with plasty of the external carotid artery was carried out in 7 patients and resection of the internal carotid artery for pathological tortuosity was carried out in 2 patients. At discharge from hospital, regression of neurological symptomatology was noted in 46 (83%) patients. Nine (20%) patients showed complete restoration of neurological deficit, two (4%) patients were found to have increased manifestations of neurological deficit. In the postoperative period two patients died: one on postoperative day 24 from augmenting respiratory and cardiac failure, the other one on day 29 from augmenting renal insufficiency followed by cardiac failure. In both cases, autopsy revealed no signs of secondary impairment of cerebral circulation. Surgical interventions on carotid arteries performed at a multimodality vascular centre during the first 18 days after the development of ischaemic stroke in the majority of cases are accompanied and followed by regression of neurological deficit, being safe concerning the development of haemorrhagic transformation.