Observation of an isothermal glass transition in metallic glasses

Glass transition, commonly manifested upon cooling a liquid, is continuous and cooling rate dependent. For decades, the thermodynamic basis in liquid-glass transition has been at the center of debate. Here, long-time isothermal annealing was conducted via molecular dynamics simulations for metallic glasses to explore the connection of physical aging in supercooled liquid and glassy states. An anomalous two-step aging is observed in various metallic glasses, exhibiting features of supercooled liquid dynamics in the first step and glassy dynamics in the second step, respectively. Furthermore, the transition potential energy is independent of initial states, proving that it is intrinsic for a metallic glass at a given temperature. We propose that the observed dynamic transition from supercooled liquid dynamics to glassy dynamics could be glass transition manifested isothermally. On this basis, glass transition is no longer cooling rate dependent, but is shown as a clear phase boundary in the temperature-energy phase diagram. Hence, a modified out-of-equilibrium phase diagram is proposed, providing new insights into the nature of glass transition.

Iron deposition in ovarian endometriosis evaluated by magnetic resonance imaging R2* correlates with ovarian function

RESEARCH QUESTION

Does iron overload in patients with endometriosis affect ovarian function? Can a method be developed to visually reflect this?

DESIGN

Magnetic resonance imaging (MRI) R2* was used to evaluate the correlation between iron deposition of ovarian and anti-Müllerian hormone (AMH) in patients with endometriosis. All patients underwent T2* MRI scanning. Serum AMH levels were measured preoperatively. The area of focal iron deposition, iron content of the cystic fluid and AMH levels between the endometriosis and control groups were compared using non-parametric tests. The effects of iron overload on AMH secretion in mouse ovarian granulosa cells were investigated by adding different concentrations of ferric citrate to the medium.

RESULTS

A significant difference was found between endometriosis and control groups in area of iron deposition (P < 0.0001), cystic fluid iron content (P < 0.0001), R2* of lesions (P < 0.0001) and R2* of the cystic fluid (P < 0.0001). Negative correlations were found between serum AMH levels and R2* of cystic lesions in patients with endometriosis aged 18-35 years (rs = -0.6484, P < 0.0001), and between serum AMH levels and R2* of cystic fluid (rs = -0.5074, P = 0.0050). Transcription level (P < 0.0005) and secretion level (P < 0.005) of AMH significantly decreased with the increase in iron exposure.

CONCLUSION

Iron deposits can impair ovarian function, which is reflected in MRI R2*. Serum AMH levels and R2* of cystic lesions or fluid in patients aged 18-35 years had a negative correlation with endometriosis. R2* can be used to reflect the changes of ovarian function caused by iron deposition.

Enhanced Fuzzy Fault Estimation of Discrete-Time Nonlinear Systems via a New Real-Time Gain-Scheduling Mechanism

The problem of enhancing the robust performance of nonlinear fault estimation (FE) is addressed by proposing a novel real-time gain-scheduling mechanism for discrete-time Takagi-Sugeno fuzzy systems. The real-time status of the operating point for the considered nonlinear plant is characterized by using these available normalized fuzzy weighting functions at both the current and the past instants of time. To achieve this, the developed fuzzy real-time gain-scheduling mechanism produces different switching modes by introducing key tunable parameters. Thus, a pair of exclusive FE gain matrices is designed for each switching mode on the strength of time-varying balanced matrices developed in this study, respectively. Since the implementation of more FE gain matrices can be scheduled according to the real-time status of the operating point at each sampling instant, the robust performance of nonlinear FE will be enhanced over the previous methods to a great extent. Finally, considerable numerical comparisons are implemented in order to illustrate that the proposed method is much superior to those existing ones reported in the literature.

Distributed robust group output synchronization control for heterogeneous uncertain linear multi-agent systems

This paper investigates the distributed robust group output synchronization problem of heterogeneous uncertain linear leader-follower multi-agent systems (MASs), whose followers have nonidentical and parameter uncertain dynamics. To achieve cooperative tracking with multiple targets, a new group synchronization framework based upon the output regulation technique is established. In the underlying directed communication topology, all nonidentical followers are divided into several subgroups. Meanwhile, each subgroup has its output tracking objective generated by an autonomous exosystem which is seen as the leader of each subgroup. Since not all followers can access their exosystems directly, the distributed exosystem observer based on the algebraic Riccati inequality (ARI) is designed to obtain the information of exosystems. Moreover, to compensate for parameter uncertainties for different group topologies, the p-copy internal model is synthesized into distributed control laws, i.e., dynamic state feedback control protocol under an acyclic directed graph and dynamic output feedback control protocol under a general directed graph. It is shown that group synchronization can be respectively achieved with these controllers under acyclic and general partitions regardless of parameter uncertainties. Finally, some examples are provided to verify the validity of the analytic results.

Distributed Fault-Tolerant Bipartite Output Synchronization of Discrete-Time Linear Multiagent Systems

This article studies the distributed fault-tolerant bipartite output synchronization problem of discrete-time linear multiagent systems (MASs) with process faults under a general directed signed graph. The reference signal is generated by an autonomous exosystem, which can also be seen as a leader. All followers are divided into two subgroups with antagonistic interactions, and the followers in each subgroup are cooperative. We aim to solve the bipartite fault-tolerant control (FTC) problem via the output regulation theory such that bipartite output synchronization can be achieved in the presence of process faults, that is, the outputs of followers with different subgroups can approach the output of exosystem with the same magnitude and the opposite sign regardless of process faults. To estimate the states and the faults of each follower, a simultaneous state and fault estimator based on the neighboring signed output estimation error and the standard discrete-time algebraic Riccati equation (ARE) is designed. Besides, a new exosystem observer with two classes of convergence conditions relying on the respective solutions of standard and modified AREs is provided. All eigenvalues of the exosystem matrix can lie completely outside the unit circle. Based on these estimations, we present a distributed fault-tolerant output feedback controller, which can overcome the no-loops constraint. Finally, simulation results are given to demonstrate the analytic results.

Relating Translation Efficiency to Protein Networks Provides Evolutionary Insights in Shewanella and Its Implications for Extracellular Electron Transfer

Shewanella species are well-known for their extracellular electron transfer (EET) capacity, by which these microorganisms can transfer the electrons from intracellular environment to extracellular space for the reduction of the extracellular insoluble electron acceptors. Using a time-stamped data for the paired protein-mRNA, we investigate the impact of differential translation on the EET process of Shewanella oneidensis MR-1. Firstly, differentially translated proteins when O₂ levels are switched from high-O₂ to low-O₂ are identified by using a soft clustering method, 629 up-regulated translated proteins and 767 down-regulated translated proteins are considered to reflect the changes from inactivated to activated EET process. Then, we showed that the degrees of connectivity of differentially translated proteins were significantly larger than those of non-differentially translated proteins, and thereby these differentially translated proteins will be more important in the protein networks. After that, we networked these differentially translated proteins to construct the differentially translated sub-networks, and discussed the most important proteins that are involved in the EET process with the help of centralization analysis of these differentially translated networks. Furthermore, we also studied the differentially translated operonic genes. Taking together, this work searches the key proteins that potentially activated the EET process from a translational efficiency viewpoint.

Finite-frequency memory filter design for uncertain linear discrete-time systems: A polynomially parameter-dependent approach

This paper investigates the robust filtering problem for linear uncertain systems affected by noises in restricted frequency intervals. Different from traditional filter schemes, a finite-frequency memory filter is designed to generalize conventional memoryless ones in such a way that a sequence of latest output measurements are employed for current estimation. To be specific, a memory filter is sought which ensures that for all admissible uncertainties, the filtering error system is asymptotically stable with a prescribed noise-attenuation level in the restricted frequency range. To accomplish this, the finite-frequency specification is characterized by the generalized Kalman-Yakubovich-Popov (KYP) lemma, aiming at improving the capability of noise-attenuation over the given frequency range. Moreover, the homogeneous polynomially parameter-dependent technique is adopted to facilitate filter design and reduce conservatism further. Based on the proposed scheme, we prove rigorously that additional past output measurements contribute to less conservative results. Finally, a quarter-car model with an active-suspension system is used to validate the proposed scheme.

A clinical study on the efficacy of Yiqi Huayu Jiedu decoction for reducing the risk of postoperative recurrence and metastasis of gastric cancer: Protocol for a multicenter, randomized, double-blind, placebo-controlled trial

BACKGROUND

Gastric cancer (GC) is one of the top 10 malignant tumors worldwide and poses a great threat to human life and health, the prevention and treatment of which has become the focus and difficulty of medical research. With its unique advantages, traditional Chinese medicine (TCM) is widely used in the prevention and treatment of postoperative recurrence and metastasis of GC as well as the improvement of patients' quality of life. The aim of this study is to elucidate the curative effect and the underlying mechanism of Yiqi Huayu Jiedu (YQHYJD) decoction.

METHODS/DESIGN

This is a prospective, multicenter, randomized controlled trial continuing 3 years. Two hundred ninety-eight eligible patients will be randomly divided into 2 groups, the chemotherapy combined with placebo and the chemotherapy combined with YQHYJD group at a ratio of 1:1. All patients will receive the treatment for 6 months and follow up for 3 years. The primary outcomes are disease-free survival, and 1-year, 2-year, 3-year progression-free survival rate, while the secondary outcomes are tumor makers, TCM syndrome score, quality of life score, overall chemotherapy completion rate, intestinal flora diversity test, immune function (T, B lymphocyte subsets and NK cells) test. The Security index includes blood, urine and stool routine, electrocardiogram, liver function (ALT), and renal function (BUN, Scr). All of these outcomes will be analyzed at the end of the trial.

DISCUSSION

This research will provide the valuable evidence for the efficacy and safety of Yiqi Huayu Jiedu decoction in postoperative GC. Furthermore, it will be helpful to form a higher level of evidence-based medical basis for TCM in the treatment of GC recurrence and metastasis.

TRIAL REGISTRATION

ChiCTR2000039038.

Data-Driven Robust Control of Discrete-Time Uncertain Linear Systems via Off-Policy Reinforcement Learning

This paper presents a model-free solution to the robust stabilization problem of discrete-time linear dynamical systems with bounded and mismatched uncertainty. An optimal controller design method is derived to solve the robust control problem, which results in solving an algebraic Riccati equation (ARE). It is shown that the optimal controller obtained by solving the ARE can robustly stabilize the uncertain system. To develop a model-free solution to the translated ARE, off-policy reinforcement learning (RL) is employed to solve the problem in hand without the requirement of system dynamics. In addition, the comparisons between on- and off-policy RL methods are presented regarding the robustness to probing noise and the dependence on system dynamics. Finally, a simulation example is carried out to validate the efficacy of the presented off-policy RL approach.

Bufalin induces mitochondrial pathway-mediated apoptosis in lung adenocarcinoma cells

BACKGROUND

To evaluate the effects of bufalin in A549 human lung adenocarcinoma epithelial cells in vitro and assess the underlying mechanisms.

MATERIALS AND METHODS

Human A549 non-small cell lung cancer (NSCLC) cells were treated with various concentrations of bufalin. Cell proliferation was measured by CCK-8 assay, apoptotic cell percentage was calculated by flow cytometry and morphological change was observed by inverted phase contrast microscopy/transmission electron microscopy. In addition, the membrane potential of mitochondria was detected by JC-1 fluorescence microscopy assay, and the related protein expression of cytochrome C and caspase-3 was analyzed by Western blotting.

RESULTS

Bufalin could inhibit the proliferation of A549 cells via induction of apoptosis, with the evidence of characteristic morphological changes in the nucleus and mitochondria. Furthermore, bufalin decreased the mitochondrial membrane potential with up-regulation of cytochrome C in the cytosol, and activation of caspase-3.

CONCLUSIONS

Bufalin inhibits the proliferation of A549 cells and triggers mitochondria-dependent apoptosis, pointing to therapeutic application for NSCLC.

The equipment for the preparation of micro and nanoscale metallic glassy fibers

A supercooled liquid extraction method and apparatus for micro and nanoscale metallic glassy fiber preparation was developed. Using the fiber fabrication equipment, micro to nanoscale metallic glassy fibers with diameter ranging from 70 nm to 300 μm can be obtained by wire drawing in the supercooled liquid region of metallic glasses via superplastic deformation. The obtained metallic glassy fibers possess precisely designed and controlled sizes, high structural uniformity and high degree of surface smoothness.

Structural and Functional Analysis of Giant Strong Component of Bacillus thuringiensis Metabolic Network

The purpose of this work was to study the giant strong component (GSC) of B. thuringiensis metabolic network by structural and functional analysis. Based on so-called “bow tie” structure, we extracted and studied GSC with its functional significance. Global structural properties such as degree distribution and average path length were computed and indicated that the GSC is also a small-world and scale-free network. Furthermore, the GSC was decomposed and functional significant for metabolism of these divisions were investigated by comparing to KEGG metabolic pathways.