582 research outputs found
Effect of grain boundaries on ion migration in stabilized δ-Bi2O3 thin- film electrolyte
Solid electrolytes with high oxygen-ion conductivity are of significant interest for many applications. Over the past several decades, numerous studies have been conducted on the effect of grain boundaries on the process of increasing the ionic conductivity of solid electrolytes. Given that nanocrystalline thin- or thick-films have been investigated in relation to lowering the operating temperature of solid electrolytes to less than 650 °C, more rigorous and quantitative assessments are necessary to determine how the ion transport characteristics are affected by the numerous interfaces formed in nano-grains devices.
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Comb-rooted multi-channel synthesis of ultra-narrow optical frequencies of few Hz linewidth
We report a multi-channel optical frequency synthesizer developed to generate
extremely stable continuous wave lasers directly out of the optical comb of an
Er-doped fiber oscillator. Being stabilized to a high-finesse cavity with a
fractional frequency stability of at 0.1 s, the comb-rooted
synthesizer produces multiple optical frequencies of ultra-narrow linewidth of
1.0 Hz at 1 s concurrently with an output power of tens of mW per each channel.
Diode-based stimulated emission by injection locking is a key mechanism that
allows comb frequency modes to sprout up with sufficient power amplification
but no loss of original comb frequency stability. Channel frequencies are
individually selectable with a 0.1 GHz increment over the entire comb bandwidth
spanning 4.25 THz around a 1550 nm center wavelength. A series of out-of-loop
test results is discussed to demonstrate that the synthesizer is able to
provide stable optical frequencies with the potential for advancing diverse
ultra-precision applications such as optical clocks comparison, atomic line
spectroscopy, photonic microwaves generation, and coherent optical
telecommunications.Comment: 19 pages, 4 figure
Observation of First-Order Metal-Insulator Transition without Structural Phase Transition in VO_2
An abrupt first-order metal-insulator transition (MIT) without structural
phase transition is first observed by current-voltage measurements and
micro-Raman scattering experiments, when a DC electric field is applied to a
Mott insulator VO_2 based two-terminal device. An abrupt current jump is
measured at a critical electric field. The Raman-shift frequency and the
bandwidth of the most predominant Raman-active A_g mode, excited by the
electric field, do not change through the abrupt MIT, while, they, excited by
temperature, pronouncedly soften and damp (structural MIT), respectively. This
structural MIT is found to occur secondarily.Comment: 4 pages, 4 figure
Depression and suicide risk prediction models using blood-derived multi-omics data
More than 300 million people worldwide experience depression; annually, ~800,000 people die by suicide. Unfortunately, conventional interview-based diagnosis is insufficient to accurately predict a psychiatric status. We developed machine learning models to predict depression and suicide risk using blood methylome and transcriptome data from 56 suicide attempters (SAs), 39 patients with major depressive disorder (MDD), and 87 healthy controls. Our random forest classifiers showed accuracies of 92.6% in distinguishing SAs from MDD patients, 87.3% in distinguishing MDD patients from controls, and 86.7% in distinguishing SAs from controls. We also developed regression models for predicting psychiatric scales with R2 values of 0.961 and 0.943 for Hamilton Rating Scale for Depression???17 and Scale for Suicide Ideation, respectively. Multi-omics data were used to construct psychiatric status prediction models for improved mental health treatment
Diclofenac impairs autophagic flux via oxidative stress and lysosomal dysfunction: Implications for hepatotoxicity
Treatment with nonsteroidal anti-inflammatory drugs (NSAIDs) is associated with various side effects, including cardiovascular and hepatic disorders. Studies suggest that mitochondrial damage and oxidative stress are important mediators of toxicity, yet the underlying mechanisms are poorly understood. In this study, we identified that some NSAIDs, including diclofenac, inhibit autophagic flux in hepatocytes. Further detailed studies demonstrated that diclofenac induced a reactive oxygen species (ROS)-dependent increase in lysosomal pH, attenuated cathepsin activity and blocked autophagosome-lysosome fusion. The reactivation of lysosomal function by treatment with clioquinol or transfection with the transcription factor EB restored lysosomal pH and thus autophagic flux. The production of mitochondrial ROS is critical for this process since scavenging ROS reversed lysosomal dysfunction and activated autophagic flux. The compromised lysosomal activity induced by diclofenac also inhibited the fusion with and degradation of mitochondria by mitophagy. Diclofenac-induced cell death and hepatotoxicity were effectively protected by rapamycin. Thus, we demonstrated that diclofenac induces the intracellular ROS production and lysosomal dysfunction that lead to the suppression of autophagy. Impaired autophagy fails to maintain mitochondrial integrity and aggravates the cellular ROS burden, which leads to diclofenac-induced hepatotoxicity.Y
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