116 research outputs found
Rats Sniff Off Toxic Air
Breathing air is
a fundamental human need, yet its safety, when
challenged by various harmful or lethal substances, is often not properly
guarded. For example, air toxicity is currently monitored only for
a single or a limited number of known toxicants, thus failing to warn
against possible hazardous air fully. Here, we discovered that, within
minutes, living rats emitted distinctive profiles of volatile organic
compounds (VOCs) via breath when exposed to various airborne toxicants
such as endotoxin, O3, ricin, and CO2. Compared
to background indoor air, when exposed to ricin or endotoxin aerosols,
breath-borne VOC levels, especially that of carbon disulfide, were
shown to decrease, while their elevated levels were observed for exposure
to O3 and CO2. A clear contrast in breath-borne
VOC profiles of rats exposed to different toxicants was observed with
a statistical significance. Differences in microRNA regulations such
as miR-33, miR-146a, and miR-155 from rats’ blood samples revealed
different mechanisms used by rats in combating different air toxicant
challenges. Similar to dogs, rats were found here to be able to sniff
off toxic air by releasing a specific breath-borne VOC profile. The
discovered science opens a new arena for online monitoring of air
toxicity and health effects of pollutants
Deposit Insurance and Bank Liquidity Creation: Evidence from a Natural Experiment in China*
In this paper, we examine how the implementation of deposit insurance influences the impact of bank capital, excess lending, banking competition and monetary policy on liquidity creation of banks. Our examination uses China’s introduction of deposit insurance in 2015 as a natural experiment. We find that deposit insurance positively reinforces the effect of capital but weakens that of monetary policy on liquidity creation. We do not find that deposit insurance has a significant influence on the effects of excess lending and competition on the liquidity creation of banks. We also show that the implementation of deposit insurance has heterogenous effects on the liquidity creation of large and small banks.</p
Nanopore Identification of N‑Acetylation by Hydroxylamine Deacetylation (NINAHD)
N-Acetyl modification,
a chemical modification
commonly found on biomacromolecules, plays a crucial role in the regulation
of cell activities and is related to a variety of diseases. However,
due to the instability of N-acetyl modification,
accurate and rapid identification of N-acetyl modification
with a low measurement cost is still technically challenging. Here,
based on hydroxylamine deacetylation and nanopore single molecule
chemistry, a universal sensing strategy for N-acetyl
modification has been developed. Acetohydroxamic acid (AHA), which
is produced by the hydroxylamine deacetylation reaction and serves
as a reporter for N-acetylation identification, is specifically sensed
by a phenylboronic acid (PBA)-modified Mycobacterium
smegmatis porin A (MspA). With this strategy, N-acetyl modifications on RNA, DNA, proteins, and glycans
were identified, demonstrating its generality. Specifically, histones
can be treated with hydroxylamine deacetylation, from which the generated
AHA can represent the amount of N-acetyl modification
detected by a nanopore sensor. The unique event features of AHA also
demonstrate the robustness of sensing against other interfering analytes
in the environment
Automated in Vivo Nanosensing of Breath-Borne Protein Biomarkers
Toxicology
and bedside medical condition monitoring is often desired
to be both ultrasensitive and noninvasive. However, current biomarker
analyses for these purposes are mostly offline and fail to detect
low marker quantities. Here, we report a system called dLABer (detection
of living animal’s exhaled breath biomarker) that integrates
living rats, breath sampling, microfluidics, and biosensors for the
automated tracking of breath-borne biomarkers. Our data show that
dLABer could selectively detect (online) and report differences (of
up to 103-fold) in the levels of inflammation agent interleukin-6
(IL-6) exhaled by rats injected with different ambient particulate
matter (PM). The dLABer system was further shown to have an up to
104 higher signal-to-noise ratio than that of the enzyme-linked
immunosorbent assay (ELISA) when analyzing the same breath samples.
In addition, both blood-borne IL-6 levels analyzed via ELISA in rats
injected with different PM extracts and PM toxicity determined by
a dithiothreitol (DTT) assay agreed well with those determined by
the dLABer system. Video recordings further verified that rats exposed
to PM with higher toxicity (according to a DTT assay and as revealed
by dLABer) appeared to be less physically active. All the data presented
here suggest that the dLABer system is capable of real-time, noninvasive
monitoring of breath-borne biomarkers with ultrasensitivity. The dLABer
system is expected to revolutionize pollutant health effect studies
and bedside disease diagnosis as well as physiological condition monitoring
at the single-protein level
Ce-Doped NiFe Layered Double Hydroxide/NiFe<sub>2</sub>O<sub>4</sub> Nanosheet Catalysts for Water Oxidation
It
is imperative to develop electrocatalysts with excellent activity
and robust stability for the oxygen evolution reaction (OER) through
simple, energy-saving methods. In this work, a Ce-doped NiFe layered
double hydroxide/NiFe2O4 nanosheet hybrid electrocatalyst
(labeled as Ce-NiFe LDH/NiFe2O4) was deposited
on a nickel foam substrate through a simple one-pot hydrothermal route.
Electrochemical investigations showed that the as-synthesized catalyst
possessed 187 mV of low overpotential at 10 mA cm–2 with a reverse scan mode in 1 M KOH solution along with superb durability
of 316 h at a current density of 500 mA cm–2, exhibiting
excellent electrocatalytic performances. Experiments revealed that
the introduction of NaCl and Ce3+ during the preparation
could markedly promote the electrocatalytic property of the catalyst.
Also, the as-prepared catalyst still presented outstanding OER electrocatalytic
performances under harsh conditions, such as seawater and strong alkaline
solutions, suggesting that the present catalyst bears great potential
in practical applications
Additional file 1 of Association between light at night and the risk of child death in sub-saharan Africa: a cross-sectional analysis based on DHS data
Supplementary Material 1: Figure S1. Flow diagram of the country selection progress in the analysis. Figure S2. Distribution of LAN in Africa in 2005. Figure S3. Changes in annual mean LAN in the 15 countries included in this study from 2005 to 2013. Figure S4. Correlation between household wealth quantile and LAN in the 15 countries included in this study. Table S1. Distribution of Under 5 mortality rate and LAN level for the study population in urban and rural areas in 15 African countries. Table S2. Stratified analysis of LAN and risk of child mortality in Afric
DataSheet1_Rational Synthesis of Freestanding NaxV2O5-rGO Paper as the Stable Cathode for Sodium Ion Batteries.PDF
Flexible NaxV2O5/rGO papers were successfully prepared via hydrothermal method followed by vacuum filtration as a high-performance cathode for SIBs. The as-prepared NaxV2O5/rGO combined flexibility and high conductivity that can buffer stress and facilitate the fast transportation of electrons during the charge-discharge process. As a result, the as-prepared NaxV2O5-rGO paper can exhibit a reversible Na-ion storage capacity of ∼197 mA h g−1 at 100 mA g−1 and a good cycling performance with 81% capacity retention for 400 cycles at a high current density of 500 mA g−1, showing great potential in flexible energy storage devices.</p
Novel Detection Method for Evaluating the Activity of an Alkaline Serine Protease from Bacillus clausii
Until
now, the detection methods for serine proteases have been
quite time-consuming or cannot indicate the “real” protease
activity. Here, a rapid and simple method for determining the “real”
activity of serine proteases toward AAPX (a kind of mixed polypeptide
substrates, with X representing 20 standard amino acids) was developed.
This AAPX method has high reliability, sensitivity, and repeatability
and can be used for detecting the serine protease activity spectrophotometrically.
Additionally, the site-directed saturation mutagenesis library of
alkaline serine protease PRO (BcPRO) from Bacillus
clausii was screened with this AAPX method. Three
beneficial mutants S99R, S99H, and S99W were identified, and S99W
displayed the highest activity. In comparison to wild-type BcPRO,
S99W exhibited enhanced catalytic performance toward eight AAPX monomers,
and the molecular dynamics simulation revealed the mechanism responsible
for its improved activity toward AAPM. Consequently, this work provides
an efficient method for detecting, characterizing, mining, and high-throughput
screening of serine proteases
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