Most known plant viruses are spread from plant to plant by insect vectors. There is strong evidence that nonpersistently transmitted viruses manipulate the release of plant volatiles to attract insect vectors, thereby promoting virus spread. The mechanisms whereby aphid settling and feeding is altered on plants infected with these viruses, however, are unclear. Here we employed loss-of-function mutations in cucumber mosaic virus (CMV) and one of its host plants, tobacco (Nicotiana tabacum), to elucidate such mechanisms. We show that, relative to a CMVD2b strain with a deletion of the viral suppressor of RNAi 2b protein in CMV, plants infected with wild-type CMV produce higher concentrations of the reactive oxygen species (ROS) H 2 O 2 in plant tissues. Aphids on wild-type CMV-infected plants engage in shorter probes, less phloem feeding, and exhibit other changes, as detected by electrical penetration graphing technology, relative to CMVD2b-infected plants. Therefore, the frequency of virus acquisition and the virus load per aphid were greater on CMV-infected plants than on CMVD2b-infected plants. Aphids also moved away from initial feeding sites more frequently on wild-type CMV infected versus CMVD2b-infected plants. The role of H 2 O 2 in eliciting these effects on aphids was corroborated using healthy plants infused with H 2 O 2. Finally, H 2 O 2 levels were not elevated, and aphid behavior was unchanged, on CMV-infected RbohD-silenced tobacco plants, which are deficient in the induction of ROS production. These results suggest that CMV uses its viral suppressor of RNAi protein to increase plant ROS levels, thereby enhancing its acquisition and transmission by vector insects.
In three-phase four-wire systems, unbalanced loads can cause grid currents to be unbalanced, and this may cause the neutral point potential on the grid side to shift. The neutral point potential shift will worsen the control precision as well as the performance of the threephase four-wire unified power quality conditioner (UPQC), and it also leads to unbalanced three-phase output voltage, even causing damage to electric equipment. To deal with unbalanced loads, this paper proposes a matching-ratio compensation algorithm (MCA) for the fundamental active component of load currents, and by employing this MCA, balanced three-phase grid currents can be realized under 100% unbalanced loads. The steady-state fluctuation and the transient drop of the DC bus voltage can also be restrained. This paper establishes the mathematical model of the UPQC, analyzes the mechanism of the DC bus voltage fluctuations, and elaborates the interaction between unbalanced grid currents and DC bus voltage fluctuations; two control strategies of UPQC under three-phase stationary coordinate based on the MCA are given, and finally, the feasibility and effectiveness of the proposed control strategy are verified by experiment results.
Provision of public services by state governments rather than municipalities is considered an important urban governance factor preventing deeper levels of socio‐spatial inequality in Australian cities. The paper examines the spatial patterns of investment by the New South Wales state government in a wide range of services and infrastructure in metropolitan Sydney over 28 budget years from 1988/89 to 2015/16. We examined the relationship between volume and type of investment in infrastructure and services, and considered a local area's socioeconomic characteristics, distance from the central business district, and designation as a strategic site in metropolitan plans. Despite an overall redistributive approach favouring relatively disadvantaged areas, the most disadvantaged suburbs in metropolitan Sydney had significantly lower levels of investment. When funding was directed to the most disadvantaged suburbs, it was often in the form of new social housing development, reinforcing both the concentration of poverty and disadvantage in resource access. The findings suggest that this is a case of under‐investment by the state government in areas already populated by disadvantaged communities rather than a market‐driven process whereby disadvantaged households move into poorly resourced neighbourhoods.
Background The World Health Organization has indicated that chronic obstructive pulmonary disease (COPD) may become the third leading cause of death by 2030. Acute exacerbation of COPD (AECOPD) is an important process in clinical treatment. Recent studies have shown that Chinese medical injections (CMI) are effective against AECOPD, but the effective difference among different CMIs remains unclear. The aim of this network meta-analysis (NMA) is to compare the therapeutic effect of various CMIs. Methods We conducted an overall, systematic literature search in the China National Knowledge Infrastructure, Wanfang, VIP, SinoMed, PubMed, Embase, Cochrane Library, and Web of Science databases to retrieve randomized controlled trials (RCTs) of CMIs for AECOPD published up to January 2021. The Cochrane risk of bias tool was used to assess the risk of bias. Stata 13.1 and WinBUGS 14.3 were used for data analyses. Results In total, 103 RCTs involving 8767 participants and 23 CMIs were included. The results indicated that among all treatments conventional Western medical therapy (WM) plus Dengzhanxixin injection (DZXX) led to the best improvement in the clinical efficacy and the ratio of forced expiratory volume in one second (FEV 1 ) to forced vital capacity (FVC) (FEV 1 /FVC), with surface under the cumulative ranking curve (SUCRA)=80.47% and 98.55%, respectively. Moreover, Shenmai injection (SM) plus WM and Reduning injection (RDN) plus WM led to the best improvement in the FEV 1 (SUCRA=80.18%) and the ratio of forced expiratory volume in one second to the predicted value (FEV 1 %, SUCRA=87.28%). Shengmai injection (SGM) plus WM led to the most considerable shortening in the length of hospital stay (SUCRA=94.70%). Cluster analysis revealed that WM+DZXX had the most favorable response for clinical efficacy and FEV 1 , as well as clinical efficacy and FEV 1 /FVC, WM+RDN had the most favorable response for clinical efficacy and FEV 1 %, WM+SGM had the most favorable response for clinical efficacy and length of hospital stay. Conclusion WM+DZXX, WM+RDN, and WM+SGM were noted to be the optimum treatment regimens for improving in clinical efficacy, FEV 1 , FEV 1 /FVC, FEV 1 % and reducing the hospital stay length of AECOPD patients. Considering the limitations this NMA may have, the current results warrant further verification via additional high-quality studies.
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