Side-by-Side and End-to-End Gold Nanorod Assemblies for Environmental Toxin Sensing

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The role of acyl-coenzyme A carboxylase complex in lipstatin biosynthesis of Streptomyces toxytricini

Streptomyces toxytricini produces lipstatin, a specific inhibitor of pancreatic lipase, which is derived from two fatty acid moieties with eight and 14 carbon atoms. The pccB gene locus in 10.6 kb fragment of S. toxytricini chromosomal DNA contains three genes for acyl-coenzyme A carboxylase (ACCase) complex accA3, pccB, and pccE that are presumed to be involved in secondary metabolism. The pccB gene encoding a β subunit of ACCase [carboxyltransferase (CT)] was identified upstream of pccE gene for a small protein of ε subunit. The accA3 encoding the α subunit of ACCase [biotin carboxylase (BC)] was also identified downstream of pccB gene. When the pccB and pccE genes were inactivated by homologous recombination, the lipstatin production was reduced as much as 80%. In contrast, the accumulation of another compound, tetradeca-5.8-dienoic acid (the major lipstatin precursor), was 4.5-fold increased in disruptant compared with wild-type. It implies that PccB of S. toxytricini is involved in the activation of octanoic acid to hexylmalonic acid for lipstatin biosynthesis

Spatiotemporal change of ecologic environment quality and human interaction factors in three gorges ecologic economic corridor, based on RSEI

The Three Gorges Ecologic Economic (Eco-Economic) Corridor is an ecological barrier in the Yangtze River's upstream and midstream areas. Due to anthropogenic activities, the corridor's ecologic environment quality has waned over the last few years. To achieve economic sustainability in this region, the premise is to assess the quality of the ecological environment in the corridor, which comprises the main counties, and to identify its response to human activities. As a result, this article developed the Remote Sensing Ecologic Index (RSEI) using MODIS data in the Three Gorges Eco-Economic Corridor from 2001 to 2019 to examine its ecological environment. Then human interaction factors affecting ecologic environment quality were probed using a Geographical Detector (geo-detector). The results showed that: (1) From 2001 to 2019, the average RSEI index of the Three Gorges Eco-Economic Corridor ranged between 0.474 and 0.655. The areas with ecological environment quality significantly worse and worse grades gathered in eastern and western regions, which is located alongside the Yangtze River and gradually radiated to surrounding areas. (2) The average ecologic environment quality level in the Three Gorges Eco-Economic Corridor was 78.19%, stable at about 75% −80% in most cases and medium and good area accounts for the main part. (3) Compared with the contribution of a single factor, multi-factor interaction had another noticeable effect on ecologic environment quality. Moreover, the top 10 multi-factor interactions were mainly between GDPs per capita and agriculture, forestry, animal husbandry, and fishery. Our research findings can be used to the realization of green economic growth in the Three Gorges Eco-Economic Corridor

Temporal Variations and Associated Remotely Sensed Environmental Variables of Dengue Fever in Chitwan District, Nepal

Dengue fever is one of the leading public health problems of tropical and subtropical countries across the world. Transmission dynamics of dengue fever is largely affected by meteorological and environmental factors, and its temporal pattern generally peaks in hot-wet periods of the year. Despite this continuously growing problem, the temporal dynamics of dengue fever and associated potential environmental risk factors are not documented in Nepal. The aim of this study was to fill this research gap by utilizing epidemiological and earth observation data in Chitwan district, one of the frequent dengue outbreak areas of Nepal. We used laboratory confirmed monthly dengue cases as a dependent variable and a set of remotely sensed meteorological and environmental variables as explanatory factors to describe their temporal relationship. Descriptive statistics, cross correlation analysis, and the Poisson generalized additive model were used for this purpose. Results revealed that dengue fever is significantly associated with satellite estimated precipitation, normalized difference vegetation index (NDVI), and enhanced vegetation index (EVI) synchronously and with different lag periods. However, the associations were weak and insignificant with immediate daytime land surface temperature (dLST) and nighttime land surface temperature (nLST), but were significant after 4–5 months. Conclusively, the selected Poisson generalized additive model based on the precipitation, dLST, and NDVI explained the largest variation in monthly distribution of dengue fever with minimum Akaike’s Information Criterion (AIC) and maximum R-squared. The best fit model further significantly improved after including delayed effects in the model. The predicted cases were reasonably accurate based on the comparison of 10-fold cross validation and observed cases. The lagged association found in this study could be useful for the development of remote sensing-based early warning forecasts of dengue fever

Present and Future of Dengue Fever in Nepal: Mapping Climatic Suitability by Ecological Niche Model

Both the number of cases of dengue fever and the areas of outbreaks within Nepal have increased significantly in recent years. Further expansion and range shift is expected in the future due to global climate change and other associated factors. However, due to limited spatially-explicit research in Nepal, there is poor understanding about the present spatial distribution patterns of dengue risk areas and the potential range shift due to future climate change. In this context, it is crucial to assess and map dengue fever risk areas in Nepal. Here, we used reported dengue cases and a set of bioclimatic variables on the MaxEnt ecological niche modeling approach to model the climatic niche and map present and future (2050s and 2070s) climatically suitable areas under different representative concentration pathways (RCP2.6, RCP6.0 and RCP8.5). Simulation-based estimates suggest that climatically suitable areas for dengue fever are presently distributed throughout the lowland Tarai from east to west and in river valleys at lower elevations. Under the different climate change scenarios, these areas will be slightly shifted towards higher elevation with varied magnitude and spatial patterns. Population exposed to climatically suitable areas of dengue fever in Nepal is anticipated to further increase in both 2050s and 2070s on all the assumed emission scenarios. These findings could be instrumental to plan and execute the strategic interventions for controlling dengue fever in Nepal

The gap of water supply-Demand and its driving factors: From water footprint view in Huaihe River Basin.

Climate change, population growth, the development of industrialization and urbanization are increasing the demand for water resources, but the water pollution is reducing the limited water supply. In recent years, the gap between water supply and demand which shows water scarcity situation is becoming more serious. Clear knowing this gap and its main driving factors could help us to put forward water protection measures correctly. We take the data of Huaihe River Basin from 2001 to 2016 as an example and use ecological water footprint to describe the demand, with the water carrying capacity representing the supply. We analyze the water supply-demand situation of Huaihe River Basin and its five provinces from footprint view in time and space. Then we apply the Logarithmic Mean Divisia Index model to analyze the driving factors of the ecological water footprint. The results show that: (1) the supply and demand balance of Huaihe River Basin was only achieved in year 2003 and 2005. There is also a large difference between Jiangsu province and other provinces in Huaihe River basin, most years in Jiangsu province per capital ecological footprint of water is more than 1 hm2/person except the years of 2003, 2015, and 2016. But other provinces are all less than 1 hm2/person. (2) Through the decomposition of water demand drivers, we concluded that economic development is the most important factor, with an annual contribution of more than 60%. Our study provides countermeasures and suggestions for the management and optimal allocation of water resources in Huaihe River Basin, and also provides reference for the formulation of water-saving policies in the world

Study of device instability of bottom-gate ZnO transistors with sol-gel derived channel layers

In this paper, the authors report the device instability of solution based ZnO thin film transistors by studying the time-evolution of electrical characteristics during electrical stressing and subsequent relaxation. A systematic comparison between ambient and vacuum conditions was carried out to investigate the effect of adsorption of oxygen and water molecules, which leads to the creation of defects in the channel layer. The observed subthreshold swing and change in field effect mobility under gate bias stressing have supported the fact that oxygen and moisture directly affect the threshold voltage shift. The authors have presented the comprehensive analysis of device relaxation under both ambient and vacuum conditions to further confirm the defect creation and charge trapping/detrapping process since it has not been reported before. It was hypothesized that chemisorbed molecules form acceptorlike traps and can diffuse into the ZnO thin film through the void on the grain boundary, being relocated even near the semiconductor/dielectric interface. The stretched exponential and power law model fitting reinforce the conclusion of defect creation by oxygen and moisture adsorption on the active layerScopu