We conducted molecular analyses to confirm four clustering HIV-1 infections (Patient A, B, C & D) in Guangzhou, China. These cases were identified by epidemiological investigation and suspected to ...acquire the infection through a common heterosexual transmission chain.
Env C2V3V4 region, gag p17/p24 junction and partial pol gene of HIV-1 genome from serum specimens of these infected cases were amplified by reverse transcription polymerase chain reaction (RT-PCR) and nucleotide sequenced.
Phylogenetic analyses indicated that their viral nucleotide sequences were significantly clustered together (bootstrap value is 99%, 98% and 100% in env, gag and pol tree respectively). Evolutionary distance analysis indicated that their genetic diversities of env, gag and pol genes were significantly lower than non-clustered controls, as measured by unpaired t-test (env gene comparison: p < 0.005; gag gene comparison: p < 0.005; pol gene comparison: p < 0.005).
Epidemiological results and molecular analyses consistently illustrated these four cases represented a transmission chain which dispersed in the locality through heterosexual contact involving commercial sex worker.
China is experiencing a rapid urbanization that is unprecedented in human history. This has significantly improved the well-being of residents, but has also caused serious environmental problems in ...the Beijing-Tianjin-Hebei urban agglomeration (BTHUA). Therefore, the study constructed the indexes of urbanization and environmental pollution based on the existing literature, used the analytic hierarchy process, entropy method and the principle of minimum information entropy to obtain the subjective, objective and comprehensive weights of the evaluation indexes respectively, and took BTHUA as an example to study the effects of urbanization elements and subsystems on environmental pollution from 2000 to 2015 by using geographically and temporally weighted regression model. This study reached the following conclusions. (1) The urbanization index increased rapidly from 0.157 in 2000 to 0.438 by 2015. National policies have significant impacts on environmental protection in urban agglomerations. (2) The service industry level, fiscal revenue, resident income, education level, Internet application were factors that reduced environmental pollution. The urbanization rate, population agglomeration, economic development, industrial development, urban construction, and transportation construction were factors that aggravated environmental pollution. (3) The impacts of urbanization on environmental pollution fluctuated periodically, with the period of fluctuation being consistent with China's five-year plan. National policy has significantly promoted the coordinated development of urbanization and environmental protection, although there was a lag effect. The effects of the trends in population, economic, social, spatial, and comprehensive urbanization factors on environmental pollution were basically the same, but the degree of each effect differed. (4) Urbanization improved the environmental quality in mountainous areas, but aggravated the degree of local environmental pollution in plains and coastal areas. The rate of urbanization of urban agglomerations differed, with the rate of urbanization lagging behind in mountainous areas, whereas it was excessive in plains and coastal areas.
•Policies impacted environmental protection significantly in urban agglomerations.•The impacts of urbanization on environmental pollution fluctuated periodically.•Policies promoted the coordination of urbanization and environmental protection.•Urbanization development paths should be set according to different topography.
•Intelligent methods were used to measure coupling effect of ESE system.•Key factors affecting coordination of ESE system were identified.•Coordination in YRDUA increased and the spatial differences ...decreased.•Economy provides great support for urban sustainability of ESE system.•Promoting the urban sustainability should focus on the relevant policies.
The rapid development of the economy and society in China has led to a series of environmental pollution problems. Exploring the interaction and coupling effects within the Economy–Society–Environment (ESE) system in urban agglomeration areas is conducive to promoting high-quality sustainable urban development. Based on systems theory, we constructed an ESE system with multiple elements, information and interaction flows. Taking the Yangtze River Delta Urban Agglomeration (YRDUA) in the period from 2010 to 2018 as a research sample, we used the Entropy Method (EM) and the Coupling Coordination Degree Model (CCDM) to synthetically evaluate the coupling coordination degree of the ESE system. The Back-Propagation Artificial Neural Network (BPANN) was applied to explore the influencing factors of the ESE system’s coupling coordination degree considering the nonlinear relationship between the various indicators and the ESE system’s coupling coordination degree. The main results can be summarized as follows. (1) The coupling coordination degree of the ESE system and the comprehensive quality of its subsystems in the YRDUA showed trends of growth during 2010–2018. There were obvious spatial differences: Shanghai had the highest quality scores, Jiangsu and Zhejiang had medium values, and Anhui had the lowest scores. However, these disparities continued to decrease during the study period. The overall coupling coordination degree distribution presents a normal distribution shape, most of cities concentrated in the moderate coordination grade. (2) At present, the coupling coordination of the society-environment binary system makes a great contribution to the ESE ternary system. (3) The comprehensive quality of the economy provides strong support for sustainable social and environmental development. (4) Factors such as the urbanization rate, proportion of tertiary industry in GDP, per-capita retail sales of consumer goods are critical to the coordinated development of the ESE system.
Numerous environmental problems have been seen due to the “high energy consumption, high pollution, high emissions” economic model in the Beijing-Tianjin-Hebei urban agglomeration (BTHUA). The ...coupling coordination degree model is applied to provide a coordination of urbanization and ecological environment composite system (CUECS) value while a geographic detector is applied to explore the dominant factors controlling it. This study reached the following conclusions. (1)The CUECS types are mainly low coordination, but which generally exhibit positive evolutionary trend. The change trends can be characterized as urbanization lags followed by system equilibrium followed by ecological environmental lags. (2)The CUECS conforms to a core-edge distributional pattern that comprises plain high mountain low, inland high coastal low. Industrialization played a key role in the development of BTHUA, the landform type was the important factor controlling CUECS. (3) Social consumer goods, gross domestic product, the disposable income of urban residents (all per capita) are the core factors controlling CUECS within different spatial units. Urbanization rate, per capita social consumer goods, the proportion of tertiary industrial population are the core factors controlling CUECS during different urbanization development stages. (4)The relative impacts of urbanization and ecological environmental subsystems on CUECS are (in decreasing order of importance) population urbanization, economic urbanization, social urbanization, ecological environment subsystem. Therefore, green urbanization remains the primary path for sustainable development within the urban agglomeration. It is unsuitable for rapid urbanization development model in the mountainous areas that encapsulate ecological and environmental security as their main functions, so the government urgently needs to amend its ‘one size fits all’ policy system.
•Coordination of urbanization and ecological environment composite system (CUECS) shows core-edge pattern with plain high mountain low, inland high coastal low.•Consumption, gross domestic product, income are core factors controlling CUECS within different spatial units.•Urbanization rate, consumption, service industry are core factors controlling CUECS during different urbanization stages.•Relative impacts on CUECS sort as population urbanization, economic urbanization, social urbanization, ecological environment subsystem.•Green urbanization remains primary path for sustainable development of urban agglomeration.
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•Known categories of open-shell iron hydrocarbyls are summarized.•Preparation methods and structural features are summarized.•Spectroscopic features of open-shell iron hydrocarbyls ...are summarized.•The diversified reactivities of open-shell iron hydrocarbyls are summarized.
Open-shell iron hydrocarbyl species attract great interests in the recent years for their relevance to the key intermediates of many iron-catalyzed organic transformations, and also their rich electronic structures that might lead to unique physical properties. While a plenty of studies on open-shell iron hydrocarbyls are scattered in literature, pertinent review on the chemistry of this type of intriguing complexes is lacking. In this article, we summarize the synthetic methods, structure and spectroscopic features, as well as the established reactivity of open-shell iron hydrocarbyl complexes, particularly those with the coordination numbers less than five. As we shall see, while the preparation methods of open-shell iron hydrocarbyls parallel with those of their closed-shell analogs, the open-shell nature of this type of organo-iron species could endow them unique spectroscopic features and also reactivity.
A three-coordinate cobalt(I) complex exhibits high catalytic efficiency and selectivity as well as good functional group compatibility in alkyne hydrosilylation. Co(IAd)(PPh3)(CH2TMS) (1) (IAd ...= 1,3-diadamantylimidazol-2-ylidene) facilitates regio- and stereoselective hydrosilylation of terminal, symmetrical internal, and trimethylsilyl-substituted unsymmetrical internal alkynes to produce single hydrosilylation products in the forms of β-(E)-silylalkenes, (E)-silylalkenes, and (Z)-α,α-disilylalkenes, respectively, in high yields. The comparable catalytic efficiency and selectivity of the Co(I) silyl complex Co(IAd)(PPh3)(SiHPh2) that was prepared from the reaction of 1 with H2SiPh2, and the isolation of an alkyne Co(I) complex Co(IAd)(η2-PhCCPh)(CH2TMS) from the reaction of 1 with the acetylene, point out a modified Chalk–Harrod catalytic cycle for these hydrosilylation reactions. The high selectivity is thought to be governed by steric factors.
This paper systematically summarizes the hierarchical cross-regional multi-directional linkage in terms of air pollution control models implemented in the Beijing-Tianjin-Hebei urban agglomeration, ...including the hierarchical linkage structure of national-urban agglomeration-city, the cross-regional linkage governance of multiple provinces and municipalities, the multi-directional linkage mechanism mainly involving industry access, energy structure, green transportation, cross-regional assistance, monitoring and warning, consultation, and accountability. The concentration data of six air pollutants were used to analyze spatiotemporal characteristics. The concentrations of SO2, NO2, PM10, PM2.5, CO decreased, and the concentration of O3 increased from 2014 to 2017; the air pollution control has achieved good effect. The concentration of O3 was the highest in summer and lowest in winter, while those of other pollutants were the highest in winter and lowest in summer. The high pollution ranges of O3 diffused from south to north, and those of other pollutants decreased significantly from north to south. Finally, we suggest strengthening the traceability and process research of heavy pollution, increasing the traceability and process research of O3 pollution, promoting the joint legislation of different regions in urban agglomeration, create innovative pollution discharge supervision mechanisms, in order to provide significant reference for the joint prevention and control of air pollution in urban agglomerations.
Pep up your carbene catalyst: A sequential cobalt‐mediated CH activation and silylation protocol has been developed for the preparation of novel silyl‐donor‐functionalized NHC complexes (see scheme; ...Mes=mesityl; R=H, Me, Ph). The resulting cobalt complexes exhibited high activity and selectivity as catalysts for the hydrosilylation of olefins.
Staphylococcus aureus
(
S. Aureus
) is a common food-borne pathogenic microorganism. Biofilm formation remains the major obstruction for bacterial elimination. The study aims at providing a basis for ...determining
S. aureus
biofilm formation. 257 clinical samples of
S. aureus
isolates were identified by routine analysis and multiplex PCR detection and found to contain 227 MRSA, 16 MSSA, 11 MRCNS, and 3 MSCNS strains. Two assays for quantification of
S. aureus
biofilm formation, the crystal violet (CV) assay and the XTT (tetrazolium salt reduction) assay, were optimized, evaluated, and further compared. In CV assay, most isolates formed weak biofilm 74.3 %), while the rest formed moderate biofilm (23.3 %) or strong biofilm (2.3 %). However, most isolates in XTT assay showed weak metabolic activity (77.0 %), while the rest showed moderate metabolic activity (17.9 %) or high metabolic activity (5.1 %). In this study, we found a distinct strain-to-strain dissimilarity in terms of both biomass formation and metabolic activity, and it was concluded from this study that two assays were mutual complementation rather than being comparison.
Viable but nonculturable (VBNC) cells are characterized by their loss of culturability, ability to maintain a nonculturable state, and potential to resuscitate.The formation of VBNC cells can occur ...under a wider range of stress conditions, many of which are moderate and long-term in nature.The VBNC state is primarily found in environmental and food industry settings, but has occasionally been observed in clinical settings.During the induction and resuscitation process, the assessment of viability and culturability are crucial indicators used to accurately determine the presence of VBNC cells.
As a unique microbial response to adverse circumstances, the viable but nonculturable (VBNC) state is characterized by the loss of culturability of microbial cells on/in nutrient media that normally support their growth, while maintaining metabolic activity. These cells can resuscitate to a culturable state under suitable conditions. Given the intrinsic importance of the VBNC state and recent debates surrounding it, there is a need to redefine and standardize the term, and to address essential questions such as ‘How to differentiate VBNC from other similar terms?’ and ‘How can VBNC cells be standardly and accurately determined?’. This opinion piece aims at contributing to an improved understanding of the VBNC state and promoting its proper handling as an underestimated and controversial microbial survival strategy.
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