15 research outputs found
Visibility-Based PM<sub>2.5</sub> Concentrations in China: 1957â1964 and 1973â2014
China
established ground PM<sub>2.5</sub> monitoring network in
late 2012 and hence the long-term and large-scale PM<sub>2.5</sub> data were lacking before 2013. In this work, we developed a national-scale
spatiotemporal linear mixed effects model to estimate the long-term
PM<sub>2.5</sub> concentrations in China from 1957 to 1964 and from
1973 to 2014 using ground visibility monitoring data as the primary
predictor. The overall model-fitting and cross-validation <i>R</i><sup>2</sup> is 0.72 and 0.71, suggesting that the model
is not overfitted. Validation beyond the model year (2014) indicated
that the model could accurately estimate historical PM<sub>2.5</sub> concentrations at the monthly (<i>R</i><sup>2</sup> =
0.71) level. The historical PM<sub>2.5</sub> estimates suggest that
air pollution is not a new environmental issue that occurs in the
recent decades but a problem existing in a longer time before 1980.
The PM<sub>2.5</sub> concentrations have reached 60â80 ÎŒg/m<sup>3</sup> in the north part of North China Plain during 1950sâ1960s
and increased to generally higher than 90 ÎŒg/m<sup>3</sup> during
1970s. The results also show that the entire China experienced an
overall increasing trend (0.19 ÎŒg/m<sup>3</sup>/yr, <i>P</i> < 0.001) in PM<sub>2.5</sub> concentrations from 1957
to 2014 with fluctuations among different periods. This paper demonstrated
visibility data allow us to understand the spatiotemporal characteristics
of PM<sub>2.5</sub> pollution in China in a long-term
Anti-influenza A Virus Activity of Dendrobine and Its Mechanism of Action
Dendrobine,
a major component of Dendrobium nobile, increasingly draws attention for its wide applications in health
care. Here we explore potential effects of dendrobine against influenza
A virus and elucidate the underlying mechanism. Our results indicated
that dendrobine possessed antiviral activity against influenza A viruses,
including A/FM-1/1/47 (H1N1), A/Puerto Rico/8/34 H274Y (H1N1), and
A/Aichi/2/68 (H3N2) with IC<sub>50</sub> values of 3.39 ± 0.32,
2.16 ± 0.91, 5.32 ± 1.68 Όg/mL, respectively. Mechanism
studies revealed that dendrobine inhibited early steps in the viral
replication cycle. Notably, dendrobine could bind to the highly conserved
region of viral nucleoprotein (NP), subsequently restraining nuclear
export of viral NP and its oligomerization. In conclusion, dendrobine
shows potential to be developed as a promising agent to treat influenza
virus infection. More importantly, the results provide invaluable
information for the full application of the Traditional Chinese Medicine
named âShi Huâ
Informing Urban Flood Risk Adaptation by Integrating Human Mobility Big Data During Heavy Precipitation
Understanding the impact of heavy precipitation on human
mobility
is critical for finer-scale urban flood risk assessment and achieving
sustainable development goals #11 to build resilient and safe cities.
Using âŒ2.6 million mobile phone signal data collected during
the summer of 2018 in Jiangsu, China, this study proposes a novel
framework to assess human mobility changes during rainfall events
at a high spatial granularity (500 m grid cell). The fine-scale mobility
map identifies spatial hotspots with abnormal clustering or reduced
human activities. When aggregating to the prefecture-city level, results
show that human mobility changes range between â3.6 and 8.9%,
revealing varied intracity movement across cities. Piecewise structural
equation modeling analysis further suggests that city size, transport
system, and crowding level directly affect mobility responses, whereas
economic conditions influence mobility through multiple indirect pathways.
When overlaying a historical urban flood map, we find such human mobility
changes help 23 cities reduce 2.6% flood risks covering 0.45 million
people but increase a mean of 1.64% flood risks in 12 cities covering
0.21 million people. The findings help deepen our understanding of
the mobility pattern of urban dwellers after heavy precipitation events
and foster urban adaptation by supporting more efficient small-scale
hazard management
GâQuadruplex Structures as a âSwitchâ Regulate ATF4 Expression in Ferroptotic HepG2 Cells
G-quadruplex (G4) is a noncanonical structure folded
in a widespread
manner by guanine-rich tandem repeated sequences. As a key response
factor, activating transcription factor 4 (ATF4) has dual functions
in managing iron-dependent ferroptosis by regulating amino acid synthesis
and antioxidant-related gene expression. In our study, the activity
of ATF4 expression was elevated in HepG2 cells induced by erastin.
Based on preliminary bioinformatics analyses, the G-tract region,
named WT, had high potential to form G4, and it was found that PDS
could markedly weaken the increase of ATF4 expression by reducing
the sensitivity of HepG2 cells toward erastin. In circular dichroism
spectra, WT oligonucleotides showed characteristic molar ellipticity
at specific wavelengths of parallel G4 structures, while corresponding
single-base mutants possessed a weaker ability to form G4, which were
consistent with immunostaining results. In addition, endogenous G4
formed by the WT motif was significantly destroyed in HepG2 cells
treated with erastin. After being transfected with WT oligonucleotides,
the levels of ATF4 mRNA decreased significantly regardless of being
treated with erastin or not. Meanwhile, mutations of G-tracts could
advantageously impact the luciferase expression downstream of an ATF4
promoter in reporter assays, manifesting that the decrease of endogenous
G4 in the ATF4 promoter was positively associated with the expression
enhanced by erastin in HepG2 cells
Dual-Functional Fluorescent Probe in the Diagnosis of Liver Injury and the Evaluation of Drug Therapy with Double Signal Amplification
Viscosity and polarity are crucial
microenvironmental parameters
within cells, intimately linked to the physiological activities of
organisms. We constructed and synthesized an innovative dual-functional
fluorescent probe, DHBP. In the green channel, the fluorescence signal
notably intensifies with decreasing environmental polarity, while
in the red channel, fluorescence signal amplification occurs due to
the collaborative effects of viscosity and polarity, resulting in
more pronounced changes. Additionally, DHBP demonstrates high sensitivity
in detecting changes in polarity and viscosity induced by drug-induced
inflammation in cells and mice. Importantly, DHBP has been effectively
utilized to monitor alterations in viscosity and polarity in the liver
injury induced by diabetes in vivo in mice and further employed to
assess the therapeutic efficacy of drugs. Therefore, DHBP holds promise
for advancing research on viscosity and polarity in future studies
of physiological and pathological processes
High Concentrations of the Antibiotic Spiramycin in Wastewater Lead to High Abundance of Ammonia-Oxidizing Archaea in Nitrifying Populations
To
evaluate the potential effects of antibiotics on ammonia-oxidizing
microbes, multiple tools including quantitative PCR (qPCR), 454-pyrosequencing,
and a high-throughput functional gene array (GeoChip) were used to
reveal the distribution of ammonia-oxidizing archaea (AOA) and archaeal <i>amoA</i> (Arch-<i>amoA</i>) genes in three wastewater
treatment systems receiving spiramycin or oxytetracycline production
wastewaters. The qPCR results revealed that the copy number ratios
of Arch-<i>amoA</i> to ammonia-oxidizing bacteria (AOB) <i>amoA</i> genes were the highest in the spiramycin full-scale
(5.30) and pilot-scale systems (1.49 Ă 10<sup>â1</sup>), followed by the oxytetracycline system (4.90 Ă 10<sup>â4</sup>), with no Arch-<i>amoA</i> genes detected in the control
systems treating sewage or inosine production wastewater. The pyrosequencing
result showed that the relative abundance of AOA affiliated with Thaumarchaeota
accounted for 78.5â99.6% of total archaea in the two spiramycin
systems, which was in accordance with the qPCR results. Mantel test
based on GeoChip data showed that Arch-<i>amoA</i> gene
signal intensity correlated with the presence of spiramycin (<i>P</i> < 0.05). Antibiotics explained 25.8% of variations
in <i>amoA</i> functional gene structures by variance partitioning
analysis. This study revealed the selection of AOA in the presence
of high concentrations of spiramycin in activated sludge systems
Complete Nutrient Removal Coupled to Nitrous Oxide Production as a Bioenergy Source by Denitrifying Polyphosphate-Accumulating Organisms
Coupled aerobicâanoxic nitrous
decomposition operation (CANDO)
is a promising emerging bioprocess for wastewater treatment that enables
direct energy recovery from nitrogen (N) in three steps: (1) ammonium
oxidation to nitrite; (2) denitrification of nitrite to nitrous oxide
(N<sub>2</sub>O); and (3) N<sub>2</sub>O conversion to N<sub>2</sub> with energy generation. However, CANDO does not currently target
phosphorus (P) removal. Here, we demonstrate that denitrifying polyphosphate-accumulating
organism (PAO) enrichment cultures are capable of catalyzing simultaneous
biological N and P removal coupled to N<sub>2</sub>O generation in
a second generation CANDO process, CANDO+P. Over 7 months (>300
cycles)
of operation of a prototype lab-scale CANDO+P sequencing batch reactor
treating synthetic municipal wastewater, we observed stable and near-complete
N removal accompanied by sustained high-rate, high-yield N<sub>2</sub>O production with partial P removal. A substantial increase in abundance
of the PAO <i>Candidatus</i> Accumulibacter phosphatis was
observed, increasing from 5% of the total bacterial community in the
inoculum to over 50% after 4 months. PAO enrichment was accompanied
by a strong shift in the dominant Accumulibacter population from clade
IIC to clade IA, based on qPCR monitoring of polyphosphate kinase
1 (<i>ppk1</i>) gene variants. Our work demonstrates the
feasibility of combining high-rate, high-yield N<sub>2</sub>O production
for bioenergy production with combined N and P removal from wastewater,
and it further suggests a putative denitrifying PAO niche for Accumulibacter
clade IA
Microbial Community Compositional Analysis for Series Reactors Treating High Level Antibiotic Wastewater
A full-scale biosystem consisting of two anaerobic reactors
(HA
and BF1) and four aerobic ones (BF2-BF4 and OD) in succession and
receiving antibiotic-bearing (mainly streptomycin) wastewater was
used for studying the impacts of antibiotics on microbial community
structures. Significant decreases of streptomycin (from 3955 ±
1910 to 23.1 ± 4.7 ÎŒg L<sup>â1</sup>) and COD<sub>Cr</sub> were observed along the treatment process. Cloning results
show that the anaerobic reactors (HA and BF1) were dominated with <i>Deltaproteobacteria</i> (51%) mainly affiliated with sulfate-reducing
bacteria (SRB), while the aerobic BF2 receiving streptomycin of 408.6
± 59.7 ÎŒg L<sup>â1</sup> was dominated with <i>Betaproteobacteria</i> (34%), <i>Deltaproteobacteria</i> (31%) and <i>Bacteroidetes</i> (14%). <i>Gammaproteobacteria</i> (15.9â22.4%), <i>Betaproteobacteria</i> (10.0â20.3%),
and <i>Bacteroidetes</i> (4.5â29.7%) became the major
bacterial groups in aerobic BF3-OD receiving streptomycin of â€83
± 13 ÎŒg L<sup>â1</sup>. Archaea affiliated with <i>Methanomethylovorans hollandica</i>-like methylotroph was abundant
in HA and BF1 (archaea/bacteria, 0.54â0.40; based on specific
gene copy number), suggesting the coexistence of SRB and methanogens
in degrading pollutants. Fungi were abundant (fungi/bacteria, 0.15;
based on specific gene copy number) with the dominance of <i>Ascomycota</i> (clone ratio of <i>Ascomycota</i>/eukarya,
25.5%) in BF2, suggesting that fungi could be an important player
in pollutant removal under high levels of antibiotics. This study
demonstrates that under high antibiotic levels, wastewater treatment
communities may maintain system stability through adjusting bacterial,
archaeal, and eukaryal compositions
High-Performance Dye-Sensitized Solar Cells Based on ColloidâSolution Deposition Planarized Fluorine-Doped Tin Oxide Substrates
The
transmittance and conductivity of fluorine-doped tin oxide (FTO) conductive
glasses are the critical factors limiting the performance of dye-sensitized
solar cells (DSSCs). Here, the transmittance and conductivity of commercial
FTO glasses were improved via a colloidâsolution deposition
planarization (CSDP) process. The process includes two steps. First,
the FTO nanocrystal colloid was deposited on the FTO glasses by spin-coating.
Secondly, the coated glasses were treated by FTO precursor solution.
Compared to the bare FTO glasses, the modified FTO glasses by the
CSDP process achieved 4% increase in transmittance (at 550 nm) and
11% decrease in sheet resistance, respectively. In addition, the modified
FTO glasses can reduce the aggregation of Pt nanoparticles and improve
the electrocatalytic activity of Pt counter electrodes. When the modified
FTO glasses were used to assemble DSSCs, the cells got a photoelectric
conversion efficiency as high as 9.37%. In contrast, the efficiency
of reference cells using bare FTO substrates was about 8.24%
Additional file 2: of Influences of De Qi induced by acupuncture on immediate and accumulated analgesic effects in patients with knee osteoarthritis: study protocol for a randomized controlled trial
SPIRIT checklist. (DOC 123ĂÂ kb