Plant and Soil - [Aims] To reveal the molecular mechanism of endophytic bacteria in Verticillium wilt-resistant cottons and deeply understand the interaction between soil and plants. [Methods]... 相似文献
ObjectivesIn December 2019, coronavirus disease 2019 (COVID-19) emerged in Wuhan City and rapidly spread across the world. The clinical characteristics of affected patients in different regions and populations may differ. Thus, this study aimed to identify the characteristics of the disease to provide an insight about the prevention and treatment of COVID-19.MethodsData on the demographic characteristics and clinical findings of the patients admitted at the First Hospital of Changsha from January 1, 2020 to February 10, 2020 were assessed.ResultsIn this study, there were 8 (3.8%) asymptomatic, 21 (10.0%) mild upper respiratory tract infection (URTI), and 180 (86.1%) pneumonia cases. In total, 47 (22.5%) patients resided in Wuhan, and 45 (21.5%) had recently traveled to Wuhan before disease onset. Moreover, 19 (9.1%) had contact with people from Wuhan, and 69 (33.0%) were family cluster cases. The median incubation period was approximately 6.3 (range: 1.0–20.0) days. Fever and cough were the most common initial symptoms: 99 (49.3%) patients presented with fever, without cough; 59 (29.4%) with cough, without fever; and 33 (16.4%) with both fever and cough.ConclusionThe symptoms of patients with COVID-19 were relatively mild outside Wuhan, and family cluster was a remarkable epidemic characteristic. Special attention should be paid to asymptomatic patients. 相似文献
The unique photo-thermal energy conversion property of polar bear hairs has long been regarded as an essential element to enable this creature to survive in extremely cold conditions.However,the relevant research was ineffectual to provide sufficient evidence of its solar energy harvesting property.In this paper,the properties of polar bear hairs were analyzed and compared systematically with those of domestic sheep wool through the measurements in the aspects of photo-thermal conversion efficiency,scanning electron microscope,fluorescence spectral and transmission of UV-visible spectra.Moreover,this study was much more focused on exploring ultraviolet utilization property of polar bear hair than previous research.The research results demonstrated that the photo-thermal property of polar bear hair was superior to those of wool fiber,especially in harvesting ultraviolet part.The potential benefits of this research lie in the development of bionic solar energy collective devices,especially in artificial solar energy collection fibers and textile products. 相似文献
Many natural proteins have been developed into drugs and produced for direct application. Identifying improved hosts to achieve
high-level heterologous protein production is a challenge in the study of heterologous protein expression in recombinant yeast.
In this study, a novel high-throughput assay to screen such overproducing Saccharomyces cerevisiae strains was systematically developed. The protocol designed was based on screening host strain derivatives with increased
superoxide dismutase dependent resistance to oxidative stress. Yeast cells transformed with recombinant plasmid carrying SOD1 gene as a reporter responded exquisitely to oxidative stress induced by elevated concentrations of paraquat. Improved yeast
strains resulting from screening clones subjected to genome shuffling through selective pressure argue for a more effective
screening system compared with traditonal selection. Moreover, this approach can be employed in general biochemical analysis
without utilization of flow cytometry or well plate reader. Therefore, it is expected that the high-throughput assay would
make superior strains producing heterologous proteins. 相似文献
Research has revealed that most chlorophyllous explants/plants in vitro have the ability to grow photoautotrophically (without
sugar in the culture medium), and that the low or negative net photosynthetic rate of plants in vitro is not due to poor photosynthetic
ability, but to the low CO2 concentration in the air-tight culture vessel during the photoperiod. Moreover, numerous studies have been conducted on improving
the in vitro environment and investigating its effects on growth and development of cultures/plantlets on nearly 50 species
since the concept of photoautotrophic micropropagation was developed more than two decades ago. These studies indicate that
the photoautotrophic growth in vitro of many plant species can be significantly promoted by increasing the CO2 concentration and light intensity in the vessel, by decreasing the relative humidity in the vessel, and by using a fibrous
or porous supporting material with high air porosity instead of gelling agents such as agar. This paper reviews the development
and characteristics of photoautotrophic micropropagation systems and the effects of environmental conditions on the growth
and development of the plantlets. The commercial applications and the perspective of photoautotrophic micropropagation systems
are discussed. 相似文献
Rift Valley Fever virus (RVFV) is an enzootic virus that causes extensive morbidity and mortality in domestic ruminants in Africa, and it has shown the potential to invade other areas such as the Arabian Peninsula. Here, we develop methods for linking mathematical models to real-world data that could be used for continent-scale risk assessment given adequate data on local host and vector populations. We have applied the methods to a well-studied agricultural region of California with 1 million dairy cattle, abundant and competent mosquito vectors, and a permissive climate that has enabled consistent transmission of West Nile virus and historically other arboviruses. Our results suggest that RVFV outbreaks could occur from February–November, but would progress slowly during winter–early spring or early fall and be limited spatially to areas with early increases in vector abundance. Risk was greatest in summer, when the areas at risk broadened to include most of the dairy farms in the study region, indicating the potential for considerable economic losses if an introduction were to occur. To assess the threat that RVFV poses to North America, including what-if scenarios for introduction and control strategies, models such as this one should be an integral part of the process; however, modeling must be paralleled by efforts to address the numerous remaining gaps in data and knowledge for this system. 相似文献
Tunable triple-peaks with the transmission intensity of more than 90% plasmonically induced transparency metamaterial resonator based on nested double π-shaped metallic structure is proposed at the terahertz frequency region, which is consisted of three sets of gold nanorods with different sizes placed on a dielectric substrate of SiO2. The coupling effect of localized electric field between different parts of the proposed structure can be used to explain the physical mechanism of three transparent windows. The finite-difference time-domain (FDTD) is used to study the spectral properties of the proposed structure, and the influence of the size of the nanorods and the relative distance between them on the spectral characteristics are also discussed. It can be seen that some obvious shift phenomena occur in the spectra with the change of these nanorods. These results indicate that the proposed structure opens up new avenues in many related applications, especially for multi-channel filters, optical switches, and sensors.