In this paper, we consider the positive solution of the coupled algebraic Riccati equation. If this equation has a positive solution, the existence and convergence rate for the solution is discussed. ...Additionally, we show special properties for the positive solution of this equation. Further, a fixed point iteration method for the minimal positive solution of the coupled algebraic Riccati equation is proposed. Finally, we offer corresponding numerical examples to show the effectiveness of the derived results.
In this paper, we discuss the existence of the positive solution for the coupled algebraic Riccati equation which is usually encountered in control theory. When this equation has a positive solution, ...Newton’s method is presented to find the minimal positive solution. Furthermore, we show some properties of Newton’s iteration method. Finally, we give corresponding numerical examples to demonstrate the effectiveness of the derived iteration method.
This study integrates hollow microneedle arrays (HMNA) with a novel jellyfish-shaped electrochemical sensor for the detection of key biomarkers, including uric acid (UA), glucose, and pH, in ...artificial interstitial fluid. The jellyfish-shaped sensor displayed linear responses in detecting UA and glucose via differential pulse voltammetry (DPV) and chronoamperometry, respectively. Notably, the open circuit potential (OCP) of the system showed a linear variation with pH changes, validating its pH-sensing capability. The sensor system demonstrates exceptional electrochemical responsiveness within the physiological concentration ranges of these biomarkers in simulated epidermis sensing applications. The detection linear ranges of UA, glucose, and pH were 0~0.8 mM, 0~7 mM, and 4.0~8.0, respectively. These findings highlight the potential of the HMNA-integrated jellyfish-shaped sensors in real-world epidermal applications for comprehensive disease diagnosis and health monitoring.
Protein p
K
a
prediction is essential
for the investigation of the pH-associated relationship between protein
structure and function. In this work, we introduce a deep learning-based
protein p
K
a
...predictor DeepKa, which is
trained and validated with the p
K
a
values
derived from continuous constant-pH molecular dynamics (CpHMD) simulations
of 279 soluble proteins. Here, the CpHMD implemented in the Amber
molecular dynamics package has been employed (
Huang
Y.
J. Chem. Inf. Model.
2018
,
58
,
1372
−
1383
29949356
). Notably, to avoid discontinuities at the boundary,
grid charges are proposed to represent protein electrostatics. We
show that the prediction accuracy by DeepKa is close to that by CpHMD
benchmarking simulations, validating DeepKa as an efficient protein
p
K
a
predictor. In addition, the training
and validation sets created in this study can be applied to the development
of machine learning-based protein p
K
a
predictors
in the future. Finally, the grid charge representation is general
and applicable to other topics, such as the protein–ligand
binding affinity prediction.
Protein secondary structures have been identified as the links in the physical processes of primary sequences, typically random coils, folding into functional tertiary structures that enable proteins ...to involve a variety of biological events in life science. Therefore, an efficient protein secondary structure predictor is of importance especially when the structure of an amino acid sequence fragment is not solved by high-resolution experiments, such as X-ray crystallography, cryo-electron microscopy, and nuclear magnetic resonance spectroscopy, which are usually time consuming and expensive. In this paper, a reductive deep learning model MLPRNN has been proposed to predict either 3-state or 8-state protein secondary structures. The prediction accuracy by the MLPRNN on the publicly available benchmark CB513 data set is comparable with those by other state-of-the-art models. More importantly, taking into account the reductive architecture, MLPRNN could be a baseline for future developments.
Human endothelial basement membrane (BM) plays a pivotal role in vascular development and homeostasis. Here, a bioresponsive film with dual-microstructured geometries was engineered to mimic the ...structural roles of the endothelial BM in developing vessels, for vascular tissue engineering (TE) application. Flexible poly(ε-caprolactone) (PCL) thin film was fabricated with microscale anisotropic ridges/grooves and through-holes using a combination of uniaxial thermal stretching and direct laser perforation, respectively. Through optimizing the interhole distance, human mesenchymal stem cells (MSCs) cultured on the PCL film’s ridges/grooves obtained an intact cell alignment efficiency. With prolonged culturing for 8 days, these cells formed aligned cell multilayers as found in native tunica media. By coculturing human umbilical vein endothelial cells (HUVECs) on the opposite side of the film, HUVECs were observed to build up transmural interdigitation cell–cell contact with MSCs via the through-holes, leading to a rapid endothelialization on the PCL film surface. Furthermore, vascular tissue construction based on the PCL film showed enhanced bioactivity with an elevated total nitric oxide level as compared to single MSCs or HUVECs culturing and indirect MSCs/HUVECs coculturing systems. These results suggested that the dual-microstructured porous and anisotropic film could simulate the structural roles of endothelial BM for vascular reconstruction, with aligned stromal cell multilayers, rapid endothelialization, and direct cell–cell interaction between the engineered stromal and endothelial components. This study has implications of recapitulating endothelial BM architecture for the de novo design of vascular TE scaffolds.
Transparent glass samples doped with bismuth nanoparticles are prepared by heat treatment of as-made glass samples. According to the results of X-ray diffraction, transmission electron microscopy, ...and energy-dispersive X-ray spectra, Bi nanoparticles are well distributed inside glasses after heat treatment. The average size of Bi nanoparticles increases with the increasing of heat treatment temperature. Because of the size effect and multiple scattering of nanoparticles, the fundamental absorption edge shows a red-shift behavior with the increasing of heat treatment temperature. Nonlinear optical properties of Bi nanoparticles doped glasses are investigated by using Z-scan technique. The maximum value of
χ
(3) of the glasses is estimated to be 2.49
×
10
−
7
esu at 800
nm. These results indicate that Bi nanoparticles doped glasses may be promising as material for optical switching.
► Transparent glass samples doped with bismuth nanoparticles are prepared by melt-quenching and subsequent annealing. ► X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectra analyses confirmed the formation of Bi nanoparticles inside glass. ► Because of the size effect and multiple scatting of nanoparticles, the fundamental absorption edge shows a red-shift behavior with increasing heat treatment temperature. ► Nonlinear optical properties of Bi nanoparticles doped glasses are investigated by using Z-scan technique.
Transparent glasses containing copper nanoparticles are promising materials for ultrafast all-optical switches in the THz region due to their wide range of resonant absorption frequencies, ultrafast ...time response, as well as large third-order nonlinear optical coefficients associated with the surface plasmon resonance (SPR) in the visible region. In this paper, three dimension controllable precipitation of copper nanoparticles inside a borosilicate glass by irradiation of femtosecond laser pulses is studied. According to the designed program, different patterns made up of copper nanoparticles can be induced inside the glass sample. Absorption spectra are used to confirm the precipitation of copper nanoparticles. The precipitated nanoparticles can be space-selectively “dissolved” by the second time femtosecond laser irradiation. The involved mechanisms are discussed.
► Cu nanoparticles are induced by femtosecond laser directly writing. ► The Cu nanoparticles are concentrated at the bottom of the modified zone. ► The Cu nanoparticles can be dissolved with a second time laser irradiation.
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