RESUMEN
In the search for natural reservoirs of hepatitis C virus (HCV), a broad diversity of non-human viruses within the Hepacivirus genus has been uncovered. However, the evolutionary dynamics that shaped the diversity and timescale of hepaciviruses evolution remain elusive. To gain further insights into the origins and evolution of this genus, we screened a large dataset of wild mammal samples (n = 1,672) from Africa and Asia, and generated 34 full-length hepacivirus genomes. Phylogenetic analysis of these data together with publicly available genomes emphasizes the importance of rodents as hepacivirus hosts and we identify 13 rodent species and 3 rodent genera (in Cricetidae and Muridae families) as novel hosts of hepaciviruses. Through co-phylogenetic analyses, we demonstrate that hepacivirus diversity has been affected by cross-species transmission events against the backdrop of detectable signal of virus-host co-divergence in the deep evolutionary history. Using a Bayesian phylogenetic multidimensional scaling approach, we explore the extent to which host relatedness and geographic distances have structured present-day hepacivirus diversity. Our results provide evidence for a substantial structuring of mammalian hepacivirus diversity by host as well as geography, with a somewhat more irregular diffusion process in geographic space. Finally, using a mechanistic model that accounts for substitution saturation, we provide the first formal estimates of the timescale of hepacivirus evolution and estimate the origin of the genus to be about 22 million years ago. Our results offer a comprehensive overview of the micro- and macroevolutionary processes that have shaped hepacivirus diversity and enhance our understanding of the long-term evolution of the Hepacivirus genus.
RESUMEN
Amorphous (a-) Fe90-xCoxSc10 alloys have been produced by rapid quenching from the melt. The Curie temperature, TC, was determined using both mean field theory and Landau's theory of second-order phase transitions in zero and non-zero external fields. The dependence of TC on the atomic spacing can be explained by the empirical Bethe-Slater curve. The value of TC of a- Fe5Co85Sc10, determined by the above theoretical approaches is 1150 K, which is the highest TC ever measured for amorphous alloys. The flattening of the measured normalized magnetization, M(T)/M(0), as a function of the reduced temperature, T/TC, is explained within the framework of the Handrich- Kobe model. According to this model the fluctuation of the exchange integral is the main reason for the flattening of M(T)/M(0). In the case of a-Fe90Sc10 without Co, however, the fluctuation of the exchange integral is dominant only at zero external field, Bex = 0. At Bex = 9 T, however, the fluctuation of the exchange integral has no conspicuous effect on the reduction of the magnetization. It is shown that at Bex = 9 T the frozen magnetic clusters control the behaviour of the reduced magnetization as function of T/TC. In contrast to other ferromagnetic alloys, where the flattening of M(T)/M(0) is characteristic for an amorphous structure, the a- Fe5Co85Sc10 does not exhibit any trace of the fluctuation of the exchange integral.
RESUMEN
The resistivity of amorphous Fe90Sc10 and Co90Sc10 alloys can be described well in terms of a simple model based on the wave character of electrons and their associated tunnelling over the temperature ranges ~1.9 K to 135 K and ~1.9 K to 12 K respectively. The extended range of agreement between experiment and theory for amorphous Fe90Sc10 is linked with its relatively small mean free path of [Formula: see text] = 0.32 nm, thus allowing electron waves to tunnel between clusters. On the other hand the restricted region of tunnelling of electron waves for amorphous Co90Sc10 alloys is linked with its relatively large mean free path of [Formula: see text] = 0.48 nm which restricts the ability for tunnelling between clusters while enabling electron waves to tunnel between different regions with a cluster.
RESUMEN
BACKGROUND: Microalgae are uniquely advantageous organisms cultured and harvested for several value-added biochemicals. A majority of these compounds are lipid-based, such as triacylglycerols (TAGs), which can be used for biofuel production, and their accumulation is most affected under nutrient stress conditions. As such, the balance between cellular homeostasis and lipid metabolism becomes more intricate to achieve efficiency in bioproduct synthesis. Lipidomics studies in microalgae are of great importance as biochemical diversity also plays a major role in lipid regulation among oleaginous species. METHODS: The aim of this study was to analyze time-series changes in lipid families produced by microalga under different nutrient conditions and growth phases to gain comprehensive information at the cellular level. For this purpose, we worked with a highly adaptable, oleaginous, non-model green microalga species, Ettlia oleoabundans (a.k.a. Neochloris oleoabundans). Using a mass spectrometry-based untargeted and targeted metabolomics' approach, we analyzed the changes in major lipid families under both replete and deplete nitrogen and phosphorus conditions at four different time points covering exponential and stationary growth phases. RESULTS: Comprehensive analysis of the lipid metabolism highlighted the accumulation of TAGs, which can be utilized for the production of biodiesel via transesterification, and depletion of chlorophylls and certain structural lipids required for photosynthesis, under nutrient deprived conditions. We also found a correlation between the depletion of digalactosyldiacylglycerols (DGDGs) and sulfoquinovosyldiacylglycerols (SQDGs) under nutrient deprivation. CONCLUSIONS: High accumulation of TAGs under nutrient limitation as well as a depletion of other lipids of interest such as phosphatidylglycerols (PGs), DGDGs, SQDGs, and chlorophylls seem to be interconnected and related to the microalgal photosynthetic efficiency. Overall, our results provided key biochemical information on the lipid regulation and physiology of a non-model green microalga, along with optimization potential for biodiesel and other value-added product synthesis.
RESUMEN
The residual electrical resistivity of metallic amorphous alloys, ρ 0, is typically in the range 50 µΩ cm < ρ 0 < 310 µΩ cm corresponding to a mean free path of conduction electrons of order a few interatomic distances. In crystalline metals with low defect levels such as Cu however, the residual electrical resistivity is about ρ 0 ≈ 1.54 × 10-2 µΩ cm, leading to extensive progression of free electrons through the crystalline material, of typically up to 4 × 106 nm. The relatively 'high' values for the electrical resistivity of distorted Sc75Fe25 alloys are discussed here within the framework of the wave character of electrons. The present investigation of amorphous and nanoglass Sc75Fe25 over the temperature range 1.9-320 K, focuses on clarification of the temperature dependence of the resistivity, ρ(T). These alloys systems, which show a range of behaviours for temperature dependent resistivity-including temperature independent residual resistivity, as well as positive and negative polarities for the slope dρ(T)/dT-are examined in detail.
RESUMEN
In this study, the magnetic properties of FeAl alloys with different grain sizes produced by high-pressure torsion were probed by means of magnetic Compton scattering. The measurements were performed at 300 and 10 K. Magnetic Compton profiles of nanocrystalline (35 nm) and ultrafine-grained (160 nm) FeAl alloys were analyzed in terms of the integral area, the width, and the distinctive dip intensity at low momenta. The changes in total magnetic moment and the strength of spin-polarization of itinerant electrons are assumed to be caused by vacancies induced during the preparation of the samples. Despite local disordering due to interfacial regions and deviations in perfect stoichiometry for B2 structure, the effect of vacancies is considered as the major magnetic state contributor.
RESUMEN
The aim of this study was to investigate the frequency of the Newcastle disease virus (NDV) infection and its virulence in exotic cage birds over a limited area and time period. A set of 335 samples was collected from 24 different species of exotic unvaccinated cage birds kept in the zoological gardens and bird markets of the Tehran province of Iran during 1.5 years. Except for three pigeons, all of the sampled birds were healthy with no clinical signs of Newcastle disease. NDV was detected in three sick pigeons by haemagglutination assay (HA), haemagglutination inhibition (HI) and reverse transcription-polymerase chain reaction (RT-PCR) tests while two of them were identified as virulent types by RT-PCR. Although the remaining samples were negative by Newcastle-disease-specific HA and HI tests, 35 of them (10%) were identified as positive and 25 (72%) were determined as the velogenic type by RT-PCR test. Five PCR products were sequenced and all were confirmed as NDV but sequences were different from each other and from other sequences from Iran. In total, 14 species (58%) were infected and 10 species were uninfected with the velogenic type without showing any signs. Pigeons are very sensitive to NDV infection and play an important role in its epidemiology. In this study, the PCR test was found to be a more sensitive and powerful method than the HA and HI tests for detection of NDV reservoirs and carrier status in exotic birds. Also, the frequency of infection with the virulent type showed that the exotic birds should probably be considered one of the main causes of recurrent annual epidemics of Newcastle disease in endemic regions.
Asunto(s)
Enfermedades de las Aves/epidemiología , Columbidae , Enfermedad de Newcastle/epidemiología , Virus de la Enfermedad de Newcastle/aislamiento & purificación , Animales , Secuencia de Bases , Enfermedades de las Aves/virología , Aves , Portador Sano/epidemiología , Portador Sano/veterinaria , Portador Sano/virología , Embrión de Pollo , Cloaca/virología , Huevos/virología , Heces/virología , Femenino , Pruebas de Inhibición de Hemaglutinación/veterinaria , Irán/epidemiología , Datos de Secuencia Molecular , Enfermedad de Newcastle/virología , Virus de la Enfermedad de Newcastle/genética , Virus de la Enfermedad de Newcastle/patogenicidad , Filogenia , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/veterinaria , Análisis de Secuencia de ADN , Especificidad de la Especie , VirulenciaRESUMEN
This cross-sectional survey aimed to provide an overview of tobacco control strategies in the countries of the Eastern Mediterranean Region (EMR). A questionnaire to collate data on implementation of 6 major policies was developed based on the previously published Tobacco Control Scale and using MPOWER measures of the WHO Tobacco Free Initiative and the Tobacco Atlas. Only 3 of the 21 countries scored higher than 50 out of 100: Islamic Republic of Iran (61), Jordan (55) and Egypt (51) More than half of countries scored less than 26. Highest scores were achieved by Afghanistan in cigarette pricing, Oman in smoking bans in public places, Islamic Republic of Iran in budgeting, prohibition of advertisements and health warnings against smoking and Syrian Arab Republic, Tunisia and Kuwait in tobacco cessation programmes. The low mean total score in EMR countries (29.7) compared with European countries (47.2) highlights the need for better future planning and policy-making for tobacco control in the Region.
Asunto(s)
Política de Salud , Nicotiana , Fumar/legislación & jurisprudencia , Publicidad/legislación & jurisprudencia , Comparación Transcultural , Estudios Transversales , Promoción de la Salud/estadística & datos numéricos , Humanos , Medio Oriente , Fumar/economía , Cese del Hábito de Fumar/legislación & jurisprudencia , Prevención del Hábito de Fumar , Impuestos/legislación & jurisprudencia , Contaminación por Humo de Tabaco/legislación & jurisprudencia , Contaminación por Humo de Tabaco/prevención & controlRESUMEN
BACKGROUND: Diabetic retinopathy is a serious microvascular disorder of the retina. Vascular endothelial growth factor (VEGF) expression, induced by high glucose levels and hypoxia, is a main feature in retinopathy. The aim of this study was to evaluate the relationship between vitreous and serum VEGF levels and control of diabetes and microalbuminuria in patients with proliferative diabetic retinopathy. METHODS: Sixty-five patients were enrolled in this case-control study, comprising 30 patients with proliferative diabetic retinopathy (cases) and 35 patients with nonproliferative diabetic retinopathy (controls). The vitreous VEGF level was compared with the serum VEGF level in both groups. Glycosylated hemoglobin (HbA(1c)), microalbuminuria, serum creatinine, and stage of nephropathy and retinopathy were also measured in patients with proliferative diabetic retinopathy, and the relationship between these parameters and serum and vitreous VEGF levels was investigated. RESULTS: Mean vitreous and serum VEGF levels were significantly higher in cases compared with controls (P = 0.001, P = 0.011, respectively). There was also a significant correlation between vitreous and serum VEGF levels (P = 0.012, r = 0.453). VEGF levels in patients with well controlled blood glucose (P = 0.039), on drug treatment (P = 0.045) and at an early stage of nephropathy (P = 0.042) were significantly lower. There was a significant correlation between VEGF and albumin to creatinine ratio (P = 0.017, r = 0.432). CONCLUSION: Serum and vitreous VEGF levels was significantly lower in patients on oral therapy, in those with well controlled glycemia, and in those with early-stage retinopathy. Administration of anti-VEGF had a good effect in reducing the progression of proliferative diabetic retinopathy.
RESUMEN
Nanoglasses are solids consisting of nanometer-sized glassy regions connected by interfaces having a reduced density. We studied the structure of Sc(75)Fe(25) nanoglasses by electron microscopy, positron annihilation spectroscopy, and small-/wide-angle X-ray scattering. The positron annihilation spectroscopy measurements showed that the as-prepared nanoglasses consisted of 65 vol% glassy and 35 vol% interfacial regions. By applying temperature annealing to the nanoglasses and measuring in situ small-angle X-ray scattering, we observed that the width of the interfacial regions increased exponentially as a function of the annealing temperature. A quantitative fit to the small-angle X-ray scattering data using a Debye-Bueche random phase model gave a correlation length that is related to the sizes of the interfacial regions in the nanoglass. The correlation length was found to increase exponentially from 1.3 to 1.7 nm when the sample temperature was increased from 25 to 230 °C. Using simple approximations, we correlate this to an increase in the width of interfacial regions from 0.8 to 1.2 nm, while the volume fraction of interfacial regions increased from 31 to 44%. Using micro-compression measurements, we investigated the deformation behavior of ribbon glass and the corresponding nanoglass. While the nanoglass exhibited a remarkable plasticity even in the annealed state owing to the glass-glass interfaces, the corresponding ribbon glass was brittle. As this difference seems not limited to Sc(75)Fe(25) glasses, the reported result suggest that nanoglasses open the way to glasses with high ductility resulting from the nanometer sized microstructure.
Asunto(s)
Cristalización/métodos , Vidrio/química , Nanoestructuras/química , Nanoestructuras/ultraestructura , Módulo de Elasticidad , Dureza , Sustancias Macromoleculares/química , Ensayo de Materiales , Conformación Molecular , Tamaño de la Partícula , Propiedades de SuperficieRESUMEN
This cross-sectional survey aimed to provide an overview of tobacco control strategies in the countries of the Eastern Mediterranean Region [EMR]. A questionnaire to collate data on implementation of 6 major policies was developed based on the previously published Tobacco Control Scale and using MPOWER measures of the WHO Tobacco Free Initiative and the Tobacco Atlas. Only 3 of the 21 countries scored higher than 50 out of 100: Islamic Republic of Iran [61], Jordan [55] and Egypt [51]. More than half of countries scored less than 26. Highest scores were achieved by Afghanistan in cigarette pricing, Oman in smoking bans in public places, Islamic Republic of Iran in budgeting, prohibition of advertisements and health warnings against smoking and Syrian Arab Republic, Tunisia and Kuwait in tobacco cessation programmes. The low mean total score in EMR countries [29.7] compared with European countries [47.2] highlights the need for better future planning and policy-making for tobacco control in the Region
Asunto(s)
Estudios Transversales , Encuestas y Cuestionarios , Fumar , Cese del Hábito de Fumar , Productos de Tabaco , NicotianaRESUMEN
This cross-sectional survey aimed to provide an overview of tobacco control strategies in the countries of the Eastern Mediterranean Region [EMR]. A questionnaire to collate data on implementation of 6 major policies was developed based on the previously published Tobacco Control Scale and using MPOWER measures of the WHO Tobacco Free Initiative and the Tobacco Atlas. Only 3 of the 21 countries scored higher than 50 out of 100: Islamic Republic of Iran [61], Jordan [55] and Egypt [51]. More than half of countries scored less than 26. Highest scores were achieved by Afghanistan in cigarette pricing, Oman in smoking bans in public places, Islamic Republic of Iran in budgeting, prohibition of advertisements and health warnings against smoking and Syrian Arab Republic, Tunisia and Kuwait in tobacco cessation programmes. The low mean total score in EMR countries [29.7] compared with European countries [47.2] highlights the need for better future planning and policy-making for tobacco control in the Region
RESUMEN
High mortalities in 17 canary flocks from different regions of Tehran, Iran, were reported. Necropsy and histopathologic examination revealed necrotic hepatitis and overall congestive septicaemia in carcasses. Salmonella enterica was isolated from 34 examined samples, two samples from each flock, including visceral organs of carcasses and droppings of live diseased birds. All isolates were typed as Salmonella enterica serovar Typhimurium by conventional serotyping. Antibiotic resistance profiling using 33 antibiotics and random amplification of polymorphic DNA differentiation by three primers were performed and showed an identical clonal relationship between these isolates and S. Typhimurium isolated from a sample of feedstuffs. Changing the feed ingredients along with antibiotic therapy via the drinking water by enrofloxacin solution controlled the outbreaks, and mortalities ceased. The zoonotic nature of S. Typhimurium and close contact of bird owners with pet birds in the home environment made the case significant in relation to public health.