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Pulsed power load (PPL) is a special load type in shipboard microgrids (SMGs), which consists of the generation module, energy storage system, and various types of loads. Having a reliable power supply to shipboard loads is a challenge as the SMG operates in islanded mode in most cases. Particularly, the PPLs require high transient power transfer with fast dynamics and strong robustness. Conventional solution to supply for the PPL is based on proportional-integral (PI) control, which can be used by linearizing the system around the equilibrium operation point. However, for a pulsed power supply (PPS) system, the load demand drastically changes in a short time, usually in millisecond level, making the operating point changes when the pulsed power is triggered or terminated. To supply the PPL with fast dynamics and robustness, an improved PPS control method is presented in this paper. By adopting a nonlinear sliding mode control (SMC) method, fast voltage regulation and robust pulse power tracking can be achieved. In the PPS, the PPL power demand is divided into two terms: one is the average power that is supplied by the SMG and the other is the fast pulsed power that is supplied by the storage capacitor. The size and cost of the storage capacitor are reduced as it is intentionally driven to a deep discharge. The PPS system configuration and coordination principle, SMC controllers, and sizing of passive elements in the PPS are analyzed in detail. The effectiveness of the presented PPS is verified by simulation results.

As a kind of class II medical device, medical optical radiation protective eyewears should meet the requirements of safety and effectiveness. In this study, the evaluation system of medical optical radiation protective eyewears is established. Combined with the medical device registration unit division guidelines, the classification method of medical optical radiation protective eyewears is given. Medical optical radiation protective eyewears are not only assembled spectacles, but also have special optical radiation protection performance. The performance evaluation method of medical optical radiation protective eyewears and the evaluation method of shelf life for medical optical radiation protective eyewears are given.

The study explored the methods of determining the diameter of clear optic of intraocular lenses by analyzing the design principles and influencing factors of clear optic. Measure and compare the clear optic diameters of intraocular lenses from -10.0 D to 36.0 D respectively. The measurement results of the two methods have good consistency and can be used in the measurement of clear optic. But considering the accuracy and convenience of actual measurement, profile projector measurement principle is more suitable for conventional mass production testing. The Schlieren technique method can provide more useful information in product development and feature description stage, and can be used as an auxiliary verification method for clear optic diameter measurement.

Ovarian cancer is a common cancer affecting women with high morbidity and mortality globally. Circular RNAs (circRNAs) have been found play vital roles in multifarious cancers, including OC. This study aims to explore the biological role and underlying mechanism of circ_0072995 in OC progression. Circ_0072995 was upregulated in OC tissues and cells in a stable structure. Functional experiments indicated that circ_0072995 knockdown suppressed cell proliferation, migration, invasion and accelerated cell apoptosis of OC cells. Mechanistically, miR-122-5p was a direct target of circ_0072995, and its knockdown reversed the effects of circ_0072995 silence on inhibition of OC cell progression. Meanwhile, SLC1A5 was a downstream target gene of miR-122-5p, and miR-122-5p overexpression inhibited the progression of OC cells by targeting SLC1A5. Moreover, circ_0072995 positively regulated SLC1A5 expression via sponging miR-122-5p. Circ_0072995 could play oncogenic role in tumorigenesis and malignant development of OC by regulating miR-122-5p/SLC1A5 axis, providing a novel approach for OC treatment.

The missing capability of DC fault current limitation is an inherent disadvantage in the typical half-bridge modular multilevel converter (MMC), which restricts its application in long-distance high voltage direct current (HVDC) systems. The full-bridge submodule (FBSM) and clamped double submodule (CDSM) topologies allow for fault current self-clearing, but also suffer from additional hardware cost and power losses. In this paper, an improved submodule topology utilizing the new reverse-blocking insulated gate bipolar transistor (RB-IGBT) is proposed to improve system economy without compromising its performance. The operating principles and DC fault characteristics of the proposed topology are analyzed in details, including comparison with various topologies in terms of cost, losses, fault current clearing speed and thermal. Compared with the traditional CDSM topology, the proposed RBSM can clear DC faults faster with reduced cost of switching devices. A DC fault protection strategy for MMC-HVDC system is also presented. Simulation results under normal operating, permanent and transient fault conditions are carried out to verify the effectiveness of the proposed topology.

Compared with conventional offshore wind farm with ac collection and high-voltage dc (HVDC) transmission system, the offshore wind farm with all dc system shows advantages with characteristics of higher power density, lower costs, and higher efficiency in many analyses. This letter proposed a novel all dc system for the offshore wind farm collection and integration. The presented dc system is composed of several medium-voltage (MV) dc collection systems and a dc transmission system. A novel modular isolated dc/dc converter (MIDC) topology is proposed for the MV dc collection system to raise the medium dc voltage to a higher level, while realizing the maximum power point tracking (MPPT) of the connected wind generators. Thorough comparisons of three dc/dc converter candidates are carried out, and the LLC resonant converter is found to be the optimal submodule (SM) of the MIDC. Furthermore, a two-layer control system for the MIDC is developed to obtain current and voltage sharing while achieving the MPPT of the wind generators in the meantime. A time-domain simulation model consisting of 160 SMs is developed using PSCAD, and a prototype with nine SMs is built for the experiments. The feasibility of the proposed pure dc system is verified by both the simulation and experimental results.

In recent years, cross-platform co-simulation has become an important development direction of the real-time simulation of power systems. Model segmentation is at the core of the realization of cross-platform joint simulation and parallel real-time simulation of these systems. In essence, it is based on the deep application of a system-decoupling algorithm. In order to solve problems that a single interface cannot, it considers the data interaction of large- and small-step systems at the same time This paper proposes an improved joint-simulation strategy based on the model-segmentation method for the cross-platform joint-simulation technology of a large-scale, flexible direct-power grid sent by the wind farms of RT-lab and Hypersim. Firstly, by studying several common interface algorithms in the current project, the adaptability of different interface algorithms is analyzed. Secondly, the problem of high-frequency oscillation caused by the inductance-decoupling algorithm is improved, and an improved segmentation-model algorithm is proposed. Finally, according to the adaptability, each interface algorithm is applied to the wind-power-based, flexible direct-transmission, dual-platform simulation model that was built for this study. The simulation results verify the feasibility of the improved interface in system decoupling and platform interfacing, and indicate the significantly improved accuracy and stability of the system.

This paper studies the time-frequency characteristics of short-circuit currents in a wind farm during the low-voltage ride-through (LVRT) process. The short-circuit current contains low-order harmonics that may affect second harmonic restraint component of transformer differential protection, while the second harmonic restraint is a classical way to block the differential relay during inrush events for the transformer. A maloperation case of the differential protection employed by the interconnecting transformer of wind farm under the LVRT process is investigated in this paper. It indicates that the second harmonic restraint cannot identify the inrush events reliably of the transformer in a wind farm. A visualization algorithm is proposed to identify the magnetizing inrush current of interconnecting transformer in wind farm based on multivariate empirical mode decomposition and multivariate multiscale fuzzy entropy (MMFE). The current is firstly decomposed into several aligned intrinsic mode functions for the signal preprocessing to reduce the effects of low-order harmonics from the short-circuit current of wind farm. Then the MMFE method is used to calculate the entropy area of the preprocessed current signal. By comparing the entropy area of the transformer current with a given restraint area, the inrush current can be discriminated. The simulation results of a practical wind farm verify the accuracy and effectiveness of the proposed algorithm.

This paper proposes a topology that can quickly eliminate DC short-circuit faults for a bipolar modular-multilevel-converter based high-voltage direct-current (MMC–HVDC) transmission. The additional thyristors are augmented to each half-bridge submodule, which will be reconfigured to form a bypass line commutated converter (LCC). The bypass LCC can be paralleled with one pole of bipolar MMC–HVDC through a hybrid switch, and MMC can be switched to the bypass LCC during the DC fault. The bypass LCC is used to eliminate the DC fault given its ability to output an inverse voltage. The tripped sequence of the hybrid switch is designed and the corresponding equivalent circuits during different stages are analyzed. Afterward, the expressions of the DC fault current in different stages are deduced by the equivalent circuits. The firing angle of the bypass LCC and the conduction resistance of the hybrid switch MOA are then designed. The additional cost and power loss of the proposed scheme are compared with those of other DC fault isolation schemes. The simulation results of the DC fault case obtained by PSCAD/EMTDC are used to verify the effectiveness of the proposed scheme.

The Huntington's disease (HD) is still a devastating neurological disease without a specific cure. In this report, the peripheral blood mononuclear cells (PBMCs) from two members of a HD family from Southwestern China were reprogrammed into hiPSC lines by an episomal and non-integrating Sendai virus delivery method. The induced HD-hiPSC lines, SPPHi001-A and SPPHi002-A, were expanded and validated for their stem cell-like pluripotency, normal karyotyping, and capability of in vitro differentiation into three germ-layers. These newly generated HD hiPSC lines from Chinese HD patients enable us to further elucidate the mechanism of HD and discover its specific treatment.

With the rapid development of modern distribution network and the access of distributed generation, the network structure is becoming increasingly complex. Frequent single-phase break faults have seriously affected equipment and personal safety and stable operation of the power system. However, with the development and application of the composite neutral grounding modes, the protection of single-phase break fault is facing new challenges. This paper proposes a protection method of single-phase break fault for distribution network considering the influence of neutral grounding modes. The characteristics of neutral voltage and sequence current are analyzed under normal operation and single-phase break fault with different grounding modes. Following this, the protection criterion based on neutral voltage and sequence current variation is constructed. The protection method of single-phase break fault for distribution network is proposed, which is applicable for various neutral grounding modes. Theoretical analysis and simulation results show that the protection method is less affected by system asymmetry, fault location and load distribution. The method has higher sensitivity, reliability and adaptability.

In this paper, we study the problem of interrupted synthetic aperture radar (SAR) imaging and coherent change detection (CCD) in the setting of gapped collections with missing pulses. Conventional interrupted SAR CCD technique is performed using a coherence estimator for paired SAR images which are reconstructed by matched-filtering (MF). However, this method suffers from substantial false alarms due to the poor resolution and high sidelobe level problems in the reconstruction. To improve image resolution and lessen the number of false alarms, sparsity-driven (SD) estimation techniques have been utilized to form SAR image pair and then apply coherence estimator to the resulting images. Actually, existing SD-based regularization SAR imaging algorithms are sensitive to the regularized parameters which are required to tune manually, leading to a serious restriction in practical application. To solve this problem, in this work, we develop an adaptive joint imaging and CCD algorithm in interrupted environments based on Bayesian framework. Our formulation utilizes a partially coherent model to incorporate prior information about the scenes and properties of changes. In particular, we model the sparsity and spatial clustering in changes by virtue of a Markov random fields (MRF) prior. To tackle the difficulty of the calculation of posterior, the mean-field variational Bayesian expectation-maximization (VBEM) method is utilized to simultaneously estimate the MRF parameters and the latent variables. Experimental results are provided to verify the effectiveness of the proposed method.

The voltage balancing of the floating capacitors in modular multilevel converter (MMC) is of great importance for the safe operation. However, the existing voltage-balancing algorithms usually suffer from high switching frequency, leading to unnecessary switching losses and device costs. This paper proposes an adaptive capacitor voltage-balancing method for high-power MMCs with reduced switching frequency. The operational characteristics and switching process of the submodules (SMs) are analyzed in detail. And then the relationship between the switching frequency and the capacitor voltage deviation is derived. Based on the analysis, an adaptive method is proposed to make a trade-off between the switching losses and the balancing effect through a closed-loop control of the alternating number of the SMs. The calculation formulas of the switching frequency are also presented. PSCAD/EMTDC simulation and RT-LAB-based real-time control hardware in the loop (HIL) test results demonstrate the effectiveness of the proposed method under different operating conditions.

Modular multilevel converter (MMC) is a well-proved circuit topology in voltage-source converter-based high voltage direct current (VSC-HVdc) transmission systems. As is known, the conventional half-bridge submodule (HBSM)-based MMC-HVdc is not suitable for overhead line transmission applications. In addition, high energy storage requirements, i.e., large capacitance is inevitable. The conventional design of the full-bridge submodule (FBSM)-based MMC usually does not utilize the negative voltage state of FBSM in normal operation. Considering the same dc voltage as with the HBSM case and utilizing the negative voltage state of the FBSM, this paper presents the design method of the power transmission capability of a single FBSM. Meanwhile, an optimized energy storage capacitance design method of the FBSM is proposed. With this method, the capacitance of FBSM can be reduced significantly. The correctness and effectiveness of the proposed method is verified by the simulation of a ±160 kV VSC-HVdc MMC and the comparison results of the dc short fault blocking and ride through capability are also provided.

Hybrid modular multilevel converter (HMMC) topology consisting of full-bridge submodules (FBSMs) and half-bridge submodules (HBSMs) is one of the promising technical solutions for long-distance high voltage direct current (HVDC) power transmission systems. However, the HMMC has very different charging circuit characteristics from the conventional half-bridge MMC (HB-MMC) topology and suffers from low and unbalanced precharge capacitor voltages and surge current when starting from the AC-side, due to its hybrid submodule configuration. In this paper, an AC-side startup scheme for the HMMC is proposed, including an additional semi-controlled charging process and an improved controlled charging method, which allows the HMMC to smoothly charge its submodule capacitors and establish the DC-link voltage without requirements of auxiliary sources. The improved controlled charging method is composed of a group modulation and a group voltage balancing control strategies, which enables the HMMC to operate stably with enhanced AC voltage output capability under the condition of low and unbalanced capacitor voltage in the HBSM group and FBSM group, thereby eliminating converter overmodulation and surge current during the startup procedures. In addition, DC-side startup strategy is also discussed in this paper. PSCAD/EMTDC simulation results based on a practical ±200 kV/750 MW HMMC-HVDC system demonstrate the effectiveness of the proposed method.

High-power electronic tetrode is the RF wave transmitting component in the ion cyclotron range of frequency (ICRF) heating system in EAST. In high-frequency use, its inter-electrode capacitance is an important factor that cannot be ignored, which will have a significant impact on the operating frequency and output power. Based on the theory of electrostatics and considering the influence of each electrode, this paper established a three-dimensional solid model of the electronic tetrode, and the numerical simulation about the inter-electrode capacitance is calculated by the finite element software COMSOL. The obtained inter-electrode capacitance simulation calculation values are all within the actual test value range. On this basis, the relationship between the inter-electrode capacitance and the inter-electrode distance is studied, and the adjustable range of the electrode diameter is calculated. The finite element numerical simulation method calculated the inter-electrode capacitance of high-power tetrodes and the quantitative relationship between the inter-electrode capacitance and inter-electrode distance more accurately, which can provide a reference for the simulation and design of megawatt-level electronic tetrodes in the future.

High-power tetrode is a key component in ion cyclotron resonance heating system, as the final amplifier component to increase the RF power to the megawatt level. Thermal analysis is of important significance to the development and use of high-power tetrodes. In this paper, the trajectory of particles during the operation of the tetrode is obtained by CST particles studio, and its energy conversion is analyzed through the simulation results. Then the grid, anode, and support structure of the tetrode are analyzed thermally in Ansys Workbench, and the results are helpful to the design of the heat dissipation structure of the tetrode.

Although antiviral drugs are available for the treatment of influenza infection, it is an urgent requirement to develop new antiviral drugs regarding the emergence of drug‐resistant viruses. The nucleoprotein (NP) is conserved among all influenza A viruses (IAVs) and has no cellular equivalent. Therefore, NP is an ideal target for the development of new IAV inhibitors. In this study, we identified a novel anti‐influenza compound, ZBMD‐1, from a library of 20,000 compounds using cell‐based influenza A infection assays. We found that ZBMD‐1 inhibited the replication of H1N1 and H3N2 influenza A virus strains in vitro, with an IC 50 ranging from 0.41–1.14 μM. Furthermore, ZBMD‐1 inhibited the polymerase activity and specifically impaired the nuclear export of NP. Further investigation indicated that ZBMD‐1 binds to the nuclear export signal 3 (NES3) domain and the dimer interface of the NP pocket. ZBMD‐1 also protected mice that were challenged with lethal doses of A/PR/8/1934 (H1N1) virus, effectively relieving lung histopathology changes, as well as strongly inhibiting the expression of pro‐inflammatory cytokines/chemokines, without inducing toxicity effects in mice. These results suggest that ZBMD‐1 is a promising anti‐influenza compound which can be further investigated as a useful strategy against IAVs in the future.

DC circuit breakers (DCCB) need high operate speed and current break ability because fault current of flexible dc grid rising fast and conventional half-bridge Modular Multilevel Converters (MMC) are short of over current tolerance ability. Fault current limiter (FCL) can retrain fault current when short-circuit fault is identified, and reduce the requirement of DCCB. The equivalent circuit of MMC with FCL is proposed in this paper, and then the fault current and voltage stress of FCL with different types of fault limiting impedance are calculated; voltage stress characteristics of FCL with the change of parameters are analyzed; a parameter coordination method for different types of fault limiting impedance is proposed. The method proposed in this paper can improve fault current limiting ability of FCL without change topological structure. Works in this paper are verified through PSCAD/EMTDC simulation.

Isolating DC bipolar short-circuit fault is one of the difficulties faced by the flexible DC distribution system. This study aims to the hybrid modular multi-level converter (MMC). Firstly, the fault-blocking mechanism of a hybrid MMC is analysed. Through theoretical calculation, the influence of the proportion of full-bridge sub-modules η on the fault isolation capability is obtained in the process of bipolar short-circuiting of the hybrid MMC-isolated DC side. Finally, the hybrid MMC DC-side bipolar short-circuit fault is simulated and analysed by the simulation model built in PSCAD/EMTDC software. The fault blocking capability of hybrid MMC and the relationship between η and the full-bridge sub-module capacitance voltage after the fault isolation phase are verified, which provides a theoretical basis for the design of the withstand voltage of hybrid MMC full-bridge sub-module capacitors.

The article is to study the objective evaluation method of the imaging quality of aspheric intraocular lens with different design concepts by establishing the model eye which is close to the actual corneal spherical aberration characteristics. Combined with the research data of corneal spherical aberration, the simulated cornea corresponding to Zernike c(4,0) coefficient 0.00 μm, 0.10 μm, 0.20 μm and 0.28 μm was established respectively. The optical quality of the measured simulated corneal lenses basically reached the theoretical design effect, and the deviation between the MTF value and the theoretical design value was equivalent to the MTF test repeatability. The establishment of model eye for artificial lens provides a research tool for the evaluation of aspheric intraocular lens imaging quality.

Metric is not only a function to mesure the distance between data points, but also a main tool to evaluate the error of data analysis, so it is one of the important factors to be considered by expert systems and intelligent systems. A general metric function is difficult to adapt to all application scenarios. Thanks to the development of big data and machine learning technology, metric learning can be used to obtain an optimal metric for a specific application scenario. Considering the fingerprinting localization (FL) as an intelligent system for processing radio signals, this paper proposes two novel novel location fingerprint (LF) metric learning algorithms to improve the accuracy and adaptability of the system. The two proposed algorithms are named LMNN-LF and NCA-LF respectively, and they are based on two famous metric learning algorithms, LMNN and NCA. Considering the distribution characteristics of position fingerprints, we modified the original cost function in both schemes. In order to accommodate the low resolution of the fingerprint, an error radius is defined in our method. The distance relation of the LFs in high dimensional space is better described by the learned metric function, which improves the accuracy of the FL system compared with the general metric function or metric learning method. Moreover, the proposed methods can also effectively extract the features or reduce the dimension of LFs, improving the accuracy of other feature-based localization algorithms. Experiments on different data sets show that the metric obtained by the proposed method and several existing methods performs good in kNN localization, and performs good in LF feature extraction and dimensionality reduction.

Wireless fingerprinting localization (FL) systems identify locations by building radio fingerprint maps, aiming to provide satisfactory location solutions for the complex environment. However, the radio map is easy to change, and the cost of building a new one is high. One research focus is to transfer knowledge from the old radio maps to a new one. Feature-based transfer learning methods help by mapping the source fingerprint and the target fingerprint to a common hidden domain, then minimize the maximum mean difference (MMD) distance between the empirical distributions in the latent domain. In this paper, the optimal transport (OT)-based transfer learning is adopted to directly map the fingerprint from the source domain to the target domain by minimizing the Wasserstein distance so that the data distribution of the two domains can be better matched and the positioning performance in the target domain is improved. Two channel-models are used to simulate the transfer scenarios, and the public measured data test further verifies that the transfer learning based on OT has better accuracy and performance when the radio map changes in FL, indicating the importance of the method in this field.

The occurrence of DC-side bipolar short-circuit faults in flexible DC transmission systems is a serious problem at present. In order to achieve fault clearing, an improved reverse-blocking hybrid submodule (RB-Hybrid-SM) topology of modular multilevel converter with DC-side fault current clearing capability is presented. All submodule (SM) capacitances of the proposed topology are series into the fault circuit and provide back electromotive force (back EMF) with converter valve blocking to clear the fault current. Then the fault clearing mechanism is analyzed, and the fault current analysis expression is pushed according to fault equivalent circuit. Finally, using this topology as an example, an improved reverse-blocking hybrid SM modular multilevel converter (RB-Hybrid-SM-MMC) simulation model was built in the PSCAD/EMTDC software are carried out to verify its effectiveness and feasibility. The simulation results show that the new SM topology proposed in this paper can quickly block the fault current, and always provide 2Uc back EMF during the fault blocking process.

The dc-link voltage deviation in multi-terminal high voltage direct current (MTDC) systems caused by droop control under various transmission power significantly increases the fluctuation rang of capacitor voltages in modular multilevel converters (MMCs). The principles of floating capacitor energy fluctuation are analyzed in this paper and an improved control method, adaptively regulating inserted submodules to maintain the stability of the cascaded capacitor voltage, is presented. Simulation results verify the feasibility and effectiveness of the control strategy.

Radio frequency (RF) fingerprinting is a commonly used indoor positioning method. However, the random fluctuation of radio signals is a major challenge for RF positioning. Traditional methods only match the signal patterns at a single time or space point without regard to the spatial or temporal pattern of the signal. Inspired by the application of neural networks in the field of natural language processing, we presents an end-to-end RF fingerprint positioning model, named RFedRNN. The model consists of two Recurrent Neural Networks (RNNs). The first RNN encodes the RF sequence into a vector from which the second RNN decodes the corresponding target path. Training this neural network is to learn a mapping from a sequence of RF fingerprints to a path, called path fingerprinting. This method has low labor cost and the parameters do not increase with the expansion of data set, which is suitable for mobile devices. Simulation and the real-world dataset experiments show that the proposed method is superior to the existing methods in positioning accuracy and robustness.

As the VSC-HVDC system has attractive advantages of high stability and controllability, it becomes a key development direction of the HVDC. Dynamic operation and controllability features of VSC-HVDC system differ a lot from that of conventional AC and DC transmission. During the grid fault, the VSC-HVDC export various short circuit current to AC system which can be a threat to the correct operation of distance protection. Based on the control principle of VSC-HVDC converter station, the voltage and phase features of the VSC-HVDC short-circuit current is analyzed. The measured impedance variation of the VSC-HVDC distance protection in AC side is also analyzed. The influence and interrelated factors of VSC-HVDC to distance protection are proposed. Digital simulation on PSCAD/EMTDC is done to verify the validity of the analysis.

Micro-grid is a small power grid consisting of micro power, energy storage equipment, control devices and loads. In the resource shortage, environmental problems, power grid security and many other pressures, the concept of micro-grid once put forward quickly by the country's attention, become a hot issue. At the same time, with the gradual deepening of micro-grid research, micro-grid operation and island operation has become an urgent need to solve the problem. In this paper, the dynamic simulation model of photovoltaic power generation, permanent magnet direct drive wind power generation, micro gas turbine, fuel cell and battery is established. The correctness of the simulation model established in this paper is verified, which lays the foundation for the economic optimization of micro-grid by using PSCAD / EMTDC software.

This paper extends the worst-case performance optimization based robust Capon beamformer (RCB) to the generalized case with possible noncircular signal-of-interest (SOI) and/or noncircular interferences. The proposed widely linear (WL) beamformer exploits the second-order noncircularity of the SOI and interferences simultaneously, and it is robust against the errors in the steering vector, sample covariance matrix and estimated noncircularity coefficient of the SOI. Further, a theoretical performance analysis for the class of WL beamformers using generalized loading in the presence of steering vector errors is presented. The superior performance of the proposed beamformer over the RCB is demonstrated by the theoretical results and various numerical experiments.

Chronic treatment of rats with D-galactose (D-gal) can mimic brain aging process. In the present study, we investigated whether and how astrocytes undergo morphological alterations due to long-term D-gal exposure. After 8 weeks of daily subcutaneous injection of D-gal, total glial cells (marked by Holzer’s crystal violet staining) and astrocytes (marked by anti-glial fibrillary acidic protein immunohistochemical labeling) of the medulla of the motor area were comparatively analyzed in control and D-gal-treated rats. We found a significant increase in the quantity of both total glial cells and astrocytes, with a higher ratio of astrocytes to total glial cells in the experimental group than the control; astrocytic body size, process number and area, and glial fibrillary acidic protein immunoreactive intensity were also increased in D-gal-treated animals. Our present study provides direct evidence that chronic administration of D-gal enhances brain astrocytic activities, which may exert compensatory functions on D-gal-induced deteriorative neurons.