231 research outputs found
On the reliability of composite analysis:an example of wet summers in North China
The validity of composite analysis is seldom discussed despite the fact that it can yield conflicting results. Our study confirms its validity by adding a reliability analysis to the classical composite analysis. Based on the signals extracted from composite analysis, 10 of the 14 wet summers in North China (1951–2020) can be “predicted” retrospectively. This study suggested the cyclonic anomaly over Mongolia at 500- and 850-hPa is closely associated with wet summers in North China. Interestingly, we found the most profound effects come from the Southern Hemisphere, with high confidence levels and large magnitude of the composite anomalies. These composite results are further cross-validated. We show that, based on the signals extracted from composite analysis, previously unseen wet summers in North China can be predicted with the mean absolute percentage error (MAPE) around 6%.</p
Optical sensing nanostructures for porous silicon rugate filters
Porous silicon rugate filters [PSRFs] and combination PSRFs [C-PSRFs] are emerging as interesting sensing materials due to their specific nanostructures and superior optical properties. In this work, we present a systematic study of the PSRF fabrication and its nanostructure/optical characterization. Various PSRF chips were produced with resonance peaks that are adjustable from visible region to near-infrared region by simply increasing the periods of sine currents in a programmed electrochemical etching method. A regression analysis revealed a perfect linear correlation between the resonant peak wavelength and the period of etching current. By coupling the sine currents with several different periods, C-PSRFs were produced with defined multiple resonance peaks located at desired positions. A scanning electron microscope and a microfiber spectrophotometer were employed to analyze their physical structure and feature spectra, respectively. The sensing properties of C-PSRFs were investigated in an ethanol vapor, where the red shifts of the C-PSRF peaks had a good linear relationship with a certain concentration of ethanol vapor. As the concentration increased, the slope of the regression line also increased. The C-PSRF sensors indicated the high sensitivity, quick response, perfect durability, reproducibility, and versatility in other organic gas sensing
MiR-539-5p alleviates sepsis-induced acute lung injury by targeting ROCK1
Introduction. Sepsis-induced acute lung injury (ALI) is an inflammatory process involved with simultaneous production of inflammatory cytokines and chemokines. In this study, we investigated the regulatory role of miR-539-5p in sepsis-induced ALI using a mouse model of cecal ligation puncture (CLP) and an in vitro model of primary murine pulmonary microvascular endothelial cells (MPVECs).
Material and methods. Adult male C57BL/6 mice were intravenously injected with or without miR-539-5p agomir or scrambled control one week before CLP operation. MPVECs were transfected with miR-539-5p mimics or control mimics, followed by lipopolysaccharide (LPS) stimulation. ROCK1 was predicted and confirmed as a direct target of miR-539-5p using dual-luciferase reporter assay. In rescue experiment, MPVECs were co-transfected with lentiviral vector expressing ROCK1 (or empty vector) and miR-539-5p mimics 24 h before LPS treatment. The transcriptional activity of caspase-3, the apoptosis ratio, the levels of miR-539-5p, interleukin-1b (IL-1b), interleukin-6 (IL-6), and ROCK1 were assessed.
Results. Compared to sham group, mice following CLP showed pulmonary morphological abnormalities, elevated production of IL-1b and IL-6, and increased caspase-3 activity and apoptosis ratio in the lung. In MPVECs, LPS stimulation resulted in a significant induction of inflammatory cytokine levels and apoptosis compared to untreated cells. The overexpression of miR-539-5p in septic mice alleviated sepsis-induced pulmonary injury, apoptosis, and inflammation. MiR-539-5p also demonstrated anti-apoptotic and anti-inflammatory effect in LPS-treated MPVECs. The upregulation of ROCK1 in MPVECs recovered miR-539-5p-suppressed caspase-3 activity and proinflammatory cytokine production.
Conclusion. In conclusion, miR-539-5p alleviated sepsis-induced ALI via suppressing its downstream target ROCK1, suggesting a therapeutic potential of miR-539-5p for the management of sepsis-induced ALI
Reliability-Latency-Rate Tradeoff in Low-Latency Communications with Finite-Blocklength Coding
Low-latency communication plays an increasingly important role in
delay-sensitive applications by ensuring the real-time exchange of information.
However, due to the constraints on the maximum instantaneous power, bounded
latency is hard to be guaranteed. In this paper, we investigate the
reliability-latency-rate tradeoff in low-latency communications with
finite-blocklength coding (FBC). More specifically, we are interested in the
fundamental tradeoff between error probability, delay-violation probability
(DVP), and service rate. Based on the effective capacity (EC) and normal
approximation, we present several gain-conservation inequalities to bound the
reliability-latency-rate tradeoffs. In particular, we investigate the
low-latency transmissions over an additive white Gaussian noise (AWGN) channel,
over a Rayleigh fading channel, with frequency or spatial diversity, and over a
Nakagami- fading channel. To analytically evaluate the
quality-of-service-constrained low-latency communications with FBC, an
EC-approximation method is further conceived to derive the closed-form
expression of quality-of-service-constrained throughput. For delay-sensitive
transmissions in which the latency threshold is greater than the channel
coherence time, we find an asymptotic form of the tradeoff between the error
probability and DVP over the AWGN and Rayleigh fading channels. Our results may
provide some insights into the efficient scheduling of low-latency wireless
communications in which statistical latency and reliability metrics are
adopted.Comment: Submitted to IEEE Trans. Inf. Theor
Active cancellation of servo-induced noise on stabilized lasers via feedforward
Many precision laser applications require active frequency stabilization.
However, such stabilization loops operate by pushing noise to frequencies
outside their bandwidth, leading to large "servo bumps" that can have
deleterious effects for certain applications. The prevailing approach to
filtering this noise is to pass the laser through a high finesse optical
cavity, which places constraints on the system design. Here, we propose and
demonstrate a different approach where a frequency error signal is derived from
a beat note between the laser and the light that passes through the reference
cavity. The phase noise derived from this beat note is fed forward to an
electro-optic modulator after the laser, carefully accounting for relative
delay, for real-time frequency correction. With a Hz-linewidth laser, we show
dB noise suppression at the peak of the servo bump (
kHz), and a noise suppression bandwidth of MHz -- well beyond the
servo bump. By simulating the Rabi dynamics of a two-level atom with our
measured data, we demonstrate substantial improvements to the pulse fidelity
over a wide range of Rabi frequencies. Our approach offers a simple and
versatile method for obtaining a clean spectrum of a narrow linewidth laser, as
required in many emerging applications of cold atoms, and is readily compatible
with commercial systems that may even include wavelength conversion
Similarity Principle and its Acoustical Verification
This study finds a similarity principle the waves emanated from the same source are similar to each other as long as two wave receivers are close enough to each other the closer to each other the wave receivers are the more similar to each other the received waves are We define the similarity mathematically and verify the similarity principle by acoustical experiment
Asymmetric Flow Control in a Slab Mold through a New Type of Electromagnetic Field Arrangement
This research aims to investigate the control effect of asymmetric flow in a slab mold using a novel magnetic field arrangement: freestanding adjustable combination electromagnetic brake (FAC-EMBr). Three scenarios (submerged entry nozzle moves to the narrow face, wide face of the slab mold, and rotates 10°) were studied using three-dimensional numerical simulation. The results show that the magnetic field generated by the FAC-EMBr system can effectively cover three key zones in mold and that the magnetic flux density in the zone cover by a vertical magnetic pole can be adjusted according to the actual flow condition. The FAC-EMBr can effectively improve the asymmetric flow in a mold and near the narrow surface caused by the asymmetric arrangement of the nozzle and can effectively inhibit the occurrence of the flow deviation phenomenon and stabilize the steel/slag interface fluctuation. At the same time, FAC-EMBr has obvious inhibition effects on the surface velocity and can optimize the asymmetric distribution of the surface velocity and the upper reflux velocity caused by the asymmetric arrangement of the nozzle. This study can provide theoretical evidence for the development and utilization of a new electromagnetic brake technology
A fast responsive chromogenic and near-infrared fluorescence lighting-up probe for visual detection of toxic thiophenol in environmental water and living cells
Thiophenols as high toxic environmental pollutants are poisonous for animals and aquatic organisms. Therefore,
it is indispensable to monitor thiophenols in the environment. Herein, a novel near-infrared fluorescent probe
was developed for the detection of thiophenols, which was easily prepared by one-step coupling of 2,4-dini trobenzenesulfonyl chloride with Nile blue. The probe showed a significant near infrared (∼675 nm) fluores cence “turn-on” response to thiophenols with some good features including chromogenic reaction, high sensi tivity and selectivity, fast response, near-infrared emission along with low detection limit (1.8 nM). The probe
was employed to rapidly and visually determine thiophenols in several industrial wastewaters with good re coveries (90–110%). Moreover, this probe has been demonstrated good capability for imaging thiophenol in
HeLa cellsinfo:eu-repo/semantics/publishedVersio
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