63 research outputs found
HSPA12B Attenuated Acute Myocardial Ischemia/reperfusion Injury via Maintaining Endothelial Integrity in a PI3K/Akt/mTOR-dependent Mechanism
Endothelial damage is a critical mediator of myocardial ischemia/reperfusion (I/R) injury. HSPA12B is an endothelial-cell-specifically expressed heat shock protein. However, the roles of HSPA12B in acute myocardial I/R injury is unknown. Here we reported that myocardial I/R upregulated HSPA12B expression in ventricular tissues, and endothelial overexpression of HSPA12B in transgenic mice (Tg) limited infarct size, attenuated cardiac dysfunction and improved cardiomyocyte survival compared with their wild type littermates. These improvements were accompanied with the diminished myocardial no-reflow phenomenon, decreased microvascular leakage, and better maintained endothelial tight junctions. The I/R-evoked neutrophil infiltration was also suppressed in Tg hearts compared with its wild type (WT) littermates. Moreover, Tg hearts exhibited the enhanced activation of PI3K/Akt//mTOR signaling following I/R challenge. However, pharmacological inhibition of PI3K abolished the HSPA12B-induced cardioprotection against myocardial I/R injury. The data demonstrate for the first time that the endothelial HSPA12B protected hearts against myocardial I/R injury. This cardioprotective action of HSPA12B was mediated, at least in part, by improving endothelial integrity in a PI3K/Akt/mTOR-dependent mechanism. Our study suggests that targeting endothelial HSPA12B could be an alternative approach for the management of patients with myocardial I/R injury
Hybrid GRU-CNN Bilinear Parameters Initialization for Quantum Approximate Optimization Algorithm
The Quantum Approximate Optimization Algorithm (QAOA), a pivotal paradigm in
the realm of variational quantum algorithms (VQAs), offers promising
computational advantages for tackling combinatorial optimization problems.
Well-defined initial circuit parameters, responsible for preparing a
parameterized quantum state encoding the solution, play a key role in
optimizing QAOA. However, classical optimization techniques encounter
challenges in discerning optimal parameters that align with the optimal
solution. In this work, we propose a hybrid optimization approach that
integrates Gated Recurrent Units (GRU), Convolutional Neural Networks (CNN),
and a bilinear strategy as an innovative alternative to conventional optimizers
for predicting optimal parameters of QAOA circuits. GRU serves to
stochastically initialize favorable parameters for depth-1 circuits, while CNN
predicts initial parameters for depth-2 circuits based on the optimized
parameters of depth-1 circuits. To assess the efficacy of our approach, we
conducted a comparative analysis with traditional initialization methods using
QAOA on Erd\H{o}s-R\'enyi graph instances, revealing superior optimal
approximation ratios. We employ the bilinear strategy to initialize QAOA
circuit parameters at greater depths, with reference parameters obtained from
GRU-CNN optimization. This approach allows us to forecast parameters for a
depth-12 QAOA circuit, yielding a remarkable approximation ratio of 0.998
across 10 qubits, which surpasses that of the random initialization strategy
and the PPN2 method at a depth of 10. The proposed hybrid GRU-CNN bilinear
optimization method significantly improves the effectiveness and accuracy of
parameters initialization, offering a promising iterative framework for QAOA
that elevates its performance
TIR/BB-Loop Mimetic AS-1 Attenuates Cardiac Ischemia/Reperfusion Injury via a Caveolae and Caveolin-3-Dependent Mechanism
AS-1, the TIR/BB loop mimetic, plays a protective role in cardiac ischemia/reperfusion (I/R) but the molecular mechanism remains unclear. The muscle specific caveolin3 (Cav-3) and the caveolae have been found to be critical for cardioprotection. This study aimed to evaluate our hypothesis that caveolae and Cav-3 are essential for AS-1-induced cardioprotection against myocardial I/R injury. To address these issues, we analyzed the involvement of Cav-3 in AS-1 mediated cardioprotection both in vivo and in vitro. We demonstrate that AS-1 administration significantly decreased infarct size, improved cardiac function after myocardial I/R and modulated membrane caveolae and Cav-3 expression in the myocardium. For in vitro studies, AS-1 treatment prevented Cav-3 re-distribution induced by H/R injury. In contrast, disruption of caveolae by MCD treatment or Cav-3 knockdown abolished the protection against H/R-induced myocytes injury by AS-1. Our findings reveal that AS-1 attenuates myocardial I/R injury through caveolae and Cav-3 dependent mechanism
UniBrain: Universal Brain MRI Diagnosis with Hierarchical Knowledge-enhanced Pre-training
Magnetic resonance imaging~(MRI) have played a crucial role in brain disease
diagnosis, with which a range of computer-aided artificial intelligence methods
have been proposed. However, the early explorations usually focus on the
limited types of brain diseases in one study and train the model on the data in
a small scale, yielding the bottleneck of generalization. Towards a more
effective and scalable paradigm, we propose a hierarchical knowledge-enhanced
pre-training framework for the universal brain MRI diagnosis, termed as
UniBrain. Specifically, UniBrain leverages a large-scale dataset of 24,770
imaging-report pairs from routine diagnostics. Different from previous
pre-training techniques for the unitary vision or textual feature, or with the
brute-force alignment between vision and language information, we leverage the
unique characteristic of report information in different granularity to build a
hierarchical alignment mechanism, which strengthens the efficiency in feature
learning. Our UniBrain is validated on three real world datasets with severe
class imbalance and the public BraTS2019 dataset. It not only consistently
outperforms all state-of-the-art diagnostic methods by a large margin and
provides a superior grounding performance but also shows comparable performance
compared to expert radiologists on certain disease types
Oxygen vacancy effects in HfO2-based resistive switching memory: First principle study
The work investigated the shape and orientation of oxygen vacancy clusters in HfO2-base resistive random access memory (ReRAM) by using the first-principle method based on the density functional theory. Firstly, the formation energy of different local Vo clusters was calculated in four established orientation systems. Then, the optimized orientation and charger conductor shape were identified by comparing the isosurface plots of partial charge density, formation energy, and the highest isosurface value of oxygen vacancy. The calculated results revealed that the [010] orientation was the optimal migration path of Vo, and the shape of system D4 was the best charge conductor in HfO2, which effectively influenced the SET voltage, formation voltage and the ON/OFF ratio of the device. Afterwards, the PDOS of Hf near Vo and total density of states of the system D4_010 were obtained, revealing the composition of charge conductor was oxygen vacancy instead of metal Hf. Furthermore, the migration barriers of the Vo hopping between neighboring unit cells were calculated along four different orientations. The motion was proved along [010] orientation. The optimal circulation path for Vo migration in the HfO2 super-cell was obtained
Dimethylammonium 5-carboxy-2-(1-oxo-1λ5-pyridin-2-yl)-1H-imidazole-4-carboxylate
In the title salt, C2H8N+·C10H6N3O5−, the imidazolecarboxylate anion is essentially planar [maximum deviation from the least-squares plane = 0.046 (5) Å], with a dihedral angle between the rings of 2.7 (2)°. This conformation is maintained by the presence of both intramolecular carboxy–carboxylate O—H...O and imidazole–oxide N—H...O hydrogen bonds. Iin the crystal, cation–carboxylate N—H...O and cation–imidazole N—H...N hydrogen bonds result in chains along the b axis
Comparison of uniform resampling and nonuniform sampling direct-reconstruction methods in k-space for FD-OCT
The nonuniform distribution of interference spectrum in wavenumber k-space is a key issue to limit the imaging quality of Fourier-domain optical coherence tomography (FD-OCT). At present, the reconstruction quality at different depths among a variety of processing methods in k-space is still uncertain. Using simulated and experimental interference spectra at different depths, the effects of common six processing methods including uniform resampling (linear interpolation (LI), cubic spline interpolation (CSI), time-domain interpolation (TDI), and K-B window convolution) and nonuniform sampling direct-reconstruction (Lomb periodogram (LP) and nonuniform discrete Fourier transform (NDFT)) on the reconstruction quality of FD-OCT were quantitatively analyzed and compared in this work. The results obtained by using simulated and experimental data were coincident. From the experimental results, the averaged peak intensity, axial resolution, and signal-to-noise ratio (SNR) of NDFT at depth from 0.5 to 3.0[Formula: see text]mm were improved by about 1.9[Formula: see text]dB, 1.4 times, and 11.8[Formula: see text]dB, respectively, compared to the averaged indices of all the uniform resampling methods at all depths. Similarly, the improvements of the above three indices of LP were 2.0[Formula: see text]dB, 1.4 times, and 11.7[Formula: see text]dB, respectively. The analysis method and the results obtained in this work are helpful to select an appropriate processing method in k-space, so as to improve the imaging quality of FD-OCT
First principle simulations on the effects of oxygen vacancy in HfO2-based RRAM
HfO2-based resistive random access memory (RRAM) takes advantage of oxygen vacancy (V o) defects in its principle of operation. Since the change in resistivity of the material is controlled by the level of oxygen deficiency in the material, it is significantly important to study the performance of oxygen vacancies in formation of conductive filament. Excluding effects of the applied voltage, the Vienna ab initio simulation package (VASP) is used to investigate the orientation and concentration mechanism of the oxygen vacancies based on the first principle. The optimal value of crystal orientation [010] is identified by means of the calculated isosurface plots of partial charge density, formation energy, highest isosurface value, migration barrier, and energy band of oxygen vacancy in ten established orientation systems. It will effectively influence the SET voltage, forming voltage, and the ON/OFF ratio of the device. Based on the results of orientation dependence, different concentration models are established along crystal orientation [010]. The performance of proposed concentration models is evaluated and analyzed in this paper. The film is weakly conductive for the samples deposited in a mixture with less than 4.167at.% of V o contents, and the resistive switching (RS) phenomenon cannot be observed in this case. The RS behavior improves with an increase in the V o contents from 4.167at.% to 6.25at.%; nonetheless, it is found difficult to switch to a stable state. However, a higher V o concentration shows a more favorable uniformity and stability for HfO2-based RRAM
Electron-Transport Properties of Few-Layer Black Phosphorus
We
perform the first-principles computational study of the effect
of number of stacking layers and stacking style of the few-layer black
phosphorus (BPs) on the electronic properties, including transport
gap, current–voltage (<i>i</i>–<i>v</i>) relation, and differential conductance. Our computation is based
on the nonequilibrium Green’s function approach combined with
density functional theory calculations. Specifically, we compute electron-transport
properties of monolayer BP, bilayer BP, and trilayer BP as well as
bilayer BPs with AB-, AA-, or AC-stacking. We find that the stacking
number has greater influence on the transport gap than the stacking
type. Conversely, the stacking type has greater influence on <i>i</i>–<i>v</i> curve and differential conductance
than on the transport gap. This study offers useful guidance for determining
the number of stacking layers and the stacking style of few-layer
BP sheets in future experimental measurements and for potential applications
in nanoelectronic devices
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