最新刊期
卷 61 ， 期 3 ， 2022
- 摘要：Alzheimer 's disease （AD） is the most common neurodegenerative disease in the elderly， and also the most common cause of dementia. The main symptoms are memory loss and progressive cognitive impairment. Amyloid β （Aβ） is one of the key proteins in the AD pathogenesis. The occurrence and development of AD caused by the accumulation of Aβ and the abnormal accumulation of β-amyloid plaques in various brain tissues was once regarded as the "amyloid cascade hypothesis" for AD pathogenesis. However， more recent evidences suggest that Aβ oligomers are in fact neurotoxins， leading to an "Aβ oligomer hypothesis"， where toxic Aβ oligomers trigger brain damages that causes the AD pathogenesis. Here we review the latest research progresses on β-amyloid protein， focusing on the process of production and aggregation of Aβ， and the classification and neurotoxicity of the Aβ oligomers. We further highlight new AD therapeutic strategies targeting the toxic Aβ oligomers， as exemplified by anti-Aβ monoclonal antibodies approved for clinic usage in recent years.关键词：Alzheimer 's disease;amyloid precursor protein;Aβ oligomer;neurotoxicity;aducanumab
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发布时间：2023-11-01
Invited review
- 摘要：Symptoms including brain atrophy, neuronal loss, neurotansmitter imbalance and cognitive decline are generally associated with Alzheimer's disease(AD), also occur in normal aging. Thus, comparing the differences between normal aging and AD is of interest to test the accelerated aging hypothesis of AD. An imbalance between excitatory/inhibitory (E/I) neurotransmission especially that originated from the dysfunction in gamma-aminobutyric acid (GABA) inhibition is involved in both AD and normal aging. In the present study, we performed correlation analyses between electroencephalograms (EEGs) and memory in middle-aged (~12 months old) wild-type mice (WT) and AD model mice (APP/PS1) after E/I balance adjustment via GABAA agonist muscimol and antagonist bicuculline administration (0.1 mg/kg intraperitoneally). Specifically, EEGs of the hippocampus and prefrontal cortex were recorded during Y-maze performance. Overall, WT and AD mice showed different correlation patterns between EEG activity and behavioral memory performance. Significant correlations were observed in EEG activity across a wider range of frequency bands (2-100 Hz, except 4-8 Hz) in WT mice, but were mainly observed in low frequency bands (delta-theta, 2-8 Hz) in AD mice. In addition, muscimol and bicuculline treatment contributed to better brain function in AD mice; in contrast, bicuculline administration resulted in poorer brain function in WT mice. Thus, our study indicates that AD pathology is distinct from the normal aging process, and the data may not support the accelerated aging hypothesis of AD. Importantly, this work reveals new insights into future AD treatment by influencing low-frequency EEG activity through E/I balance adjustment, thereby aiding cognitive recovery.关键词：aging acceleration;alzheimer′s disease (AD);bicuculline;GABAA;muscimol;spatial memory
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发布时间：2023-11-01 - 摘要：The study aimed to explore the mechanism of anti-infection of Honghe Fujie Lotion （HHFJL） through network pharmacology， and provide a scientific reference for its clinical application. 92 compounds in HHFJL were identified by GC-MS in preliminary studies. The action targets were collected by TCMSP， Toxicogenomics Database （CTD） and SwissTargetPrediction， while the infection related targets were queried through DisGeNET database， and the “compound-disease” intersection targets were obtained using Venn Diagram. The herb- active ingredient- intersection target network was constructed and analysized by Cytoscape. A total of 1 056 targets were collected for HHFJL， and 143 key targets were selected， such as PARP1， PTGS1， ESR1， IDO1， NOS2， ALOX5， EGFR， PTGS2， HDAC6， JAK1， and so on. The results from DAVID indicated that lipopolysaccharide-mediated signaling pathway， NF-kappa B signaling pathway， Toll-like receptor signaling pathway and TNF signaling pathway were the key pathways， which were involved in anti-infective therapies. HHFJL may show therapeutic effects on infection probably through inhibiting pathogenic， regulating immune function， alleviating inflammation and oxidative damage based on multi-target and multi-pathway.关键词：Honghe Fujie Lotion;infection;network pharmacology
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发布时间：2023-11-01 - 摘要：In order to discover the novel and bioactive secondary metabolites， 13 alkolides were isolated from EtOAc layer of deep sea actinomycete Actinomadura cremea on the A1 media using different kinds of chromatographic columns with SiO2， ODS， Sephadex LH-20， etc. and HPLC. Their structures were analyzed by NMR， LC-MS， ORD， and compared with the literatures. They were identified as Harmane （1）， N- acetyltryptamine （2）， N- （2-（1H-indol-3-yl） ethyl） propionamide （3），N-（4-hydroxy-phenethyl） propionamide （4）， N- acetyltyramine （5）， N-phenethylacetamide （6）， Valerolactam （7）， cyclo- （L- Phe-L-Val） （8）， cyclo （L-Pro-L-Val） （9）， cyclo-（L-Leu- L- Val） （10）， Cyclo（L-Ala-L-Val） （11）， cyclo-（L-Ile-L-Leu） （12） and cyclo-（L-Ala-L-Ile） （13）. Compounds 1，3，4，7-13 were firstly obtained from genus Actinomadura， and all of them were isolated from Actinomadura cremea for the first time. The results enriched the types of chemical structures from Actinomadura cremea.关键词：Actinomadura cremea;deep sea actinomycete;alkolides;identification
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发布时间：2023-11-01 - 摘要：The study aimed to investigate the inhibitory effects of extracts from aerial part and root of Houttuynia cordata Thunb on Deinagkistrodon acutus venom. Inhibitory effects of the extracts on proteolytic， phospholipase A2 （PLA2）， hyaluronidase， procoagulant and fibrinogenolytic activities of D. acutus venom were performed in vitro， and neutralization of hemorrhagic， edematogenic， myotoxic and lethal activities induced by the venom were evaluated in vivo. In vitro， the aerial part extract significantly inhibited the enzymatic activities of proteases， PLA2 and hyaluronidases of D. acutus venom and effectively neutralized the procoagulant and fibrinogenolytic activities produced by the venom.In vivo， the extract obviously reduced hemorrhage， edema， myotoxicity and lethality induced by the venom. The root extract exhibited similar inhibitory patterns but showed a lower effect than that of the aerial part extract at the same concentration. The results of phytochemical analysis showed that alkaloids， anthraquinones and proteins were detected in these two extracts， whereas flavonoids， polyphenols， tannins， triterpenes， sterols and saponins were only present in the aerial part extract and absent in the root extract. Our data for the first time validated the inhibitory effects of H. cordata extracts on D. acutus venom， and confirmed that the aerial part extract was much more effective than the root extract in suppression of the main enzymatic and biological activities of the venom， suggesting it could be used as a potential source for developing antidote against snakebites.关键词：Houttuynia cordata Thunb;Deinagkistrodon acutus venom;aerial part extract;root extract;inhibitory effect
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发布时间：2023-11-01 - 摘要：In recent years， metal-organic cages have played an increasingly important role in supramolecular chemistry. Metal-organic cages have specific cavities that can encapsulate various guest molecules， and thus show great potentials in such fields as catalysis， adsorption and separation. However， due to their complex structure and unstable nature of metal-organic supramolecular cages， the cage itself and its host-guest properties are difficult to be characterized by mass spectrometry. In order to solve the difficulties of the metal-organic supramolecular cage and its host-guest behavior in analyzing mass spectrometry experiment， this paper analyzes the addition of pyrene to MOC-16 by electrospray time-of-flight mass spectrometry. The research results show that mass spectrometry can effectively analyze the effects of MOC-16 and its host-guest properties.关键词：electrospray time-of-flight mass spectrometry（ESI-TOF）;Ru-Pd metal-organic supramolecular cage（MOC-16）;host-guest
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发布时间：2023-11-01 - 摘要：Derivatives of α-mangostin were designed and synthesized in this study，and their phosphodiesterase 4（PDE4） inhibitory activities were evaluated in vitro．The initial substrate α-mangostin was converted into the cyclized compound 1， followed by eleven desired compounds were prepared by alkylation， hydrolysis， acylation reaction and other methods. The structures of the desired compounds were confirmed by 1H NMR， 13C NMR and ESI-（HR）MS. The PDE4 inhibitory activities of these compounds were evaluated in vitro by ［3H］ liquid scintillation counting method. Among the desired compounds， compounds 4a，4b，5，6，8，11 and 13 showed stronger PDE4 inhibition activity than α-mangostin. Compound 5 exhibited potential PDE4 inhibitory activity with the IC50 values of 247 nmol/L.关键词：α-mangostin;derivatives;phosphodiesterase 4（PDE4）;inhibitor
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发布时间：2023-11-01 -
Effects of coastline and terrain on warm-sector heavy rainfall in the Pearl River Delta, South China
摘要：We conducted three experiments using the WRF-Chem model to examine the physical effects of the coastline and numerous low mountains along the coast in the Pearl River Delta (PRD) area on the intensity and distribution of warm-sector heavy rainfall. We analyzed dynamic effects and water vapor transport, and found that by replacing the mountains in the PRD with flat land, orographic lifting disappears, resulting in a considerable reduction of coastal convergence and water vapor accumulation at 925 hPa along the coastline;the 12 hours accumulated precipitation area is mainly confined to the north of 22.7°N which is 80 km north than without moving out the mountains, and precipitation intensity decreases. By shifting the coastline northward and thus, removing the special topography of the low mountains and the contrast of frictional forces along the original coastline, the convection caused by the convergence is greatly reduced. As a result, almost no precipitation falls in the PRD region. Instead, convection, water vapor accumulation and precipitation centers appear near the new coastline because of orographic lifting and discontinuities in surface friction. The coastline and coastal mountains of the PRD play important roles in the occurrence, intensity and distribution of precipitation.关键词：warm-sector heavy rainfall;coastline;terrain;WRF-Chem model;the Pearl River Delta area- 8
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发布时间：2023-11-01 - 摘要：This study investigates the dominant cycles of air pollutant concentrations and meteorological elements and the influence of atmospheric circulation on air quality， based on the datasets of air quality and meteorological variables in the winter seasons of 2016/2017 in Foshan. The atmospheric variables， the air quality index， and the concentration of pollutants exhibit prominent 10-25-day oscillations. The surface air pressure shows a leading change 4-5 days ahead of the air quality index （AQI） and pollutant concentration， suggesting the former may be a potential predictor of air quality. In the winter seasons， as the surface high-pressure system， the northerly wind in the lower level layer and the accompanying sinking motion in 10-25-day components， move southward from north to South China， the atmospheric stratification over South China becomes more stable. Then， the clear sky and less cloud weather will easily appear， which is conducive to the photochemical reaction of atmospheric pollutants and not conducive to the diffusion of pollutants， increasing pollutant concentration and the air quality becomes worse. In another case， as the 10-25-day components of the surface low-pressure system， the southerly wind in the lower level and the accompanying upward motion move to South China from the north， the atmospheric stratification over South China will be more unstable and prone to cloudy or rainy weather， which is conducive to the purification and dilution of air pollutants. Then the concentration of pollutants will be reduced and the air quality will be improved. As the low-pressure system is replaced by the southward high-pressure system over South China， the air quality begins to deteriorate again.关键词：atmospheric circulation;10-25-day oscillation;air quality;influence mechanism
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发布时间：2023-11-01 - 摘要：Based on POI （point of interest） data of recreational resources around the city of Guangzhou， this paper analyzed the spatial characteristics of the recreational belt around Guangzhou by use of the approaches turning radius and spatial distribution curve， the mean distance to the city center， and spatial dispersion index， and kernel density estimation. The results showed that （1） the recreational belt around the metropolis of Guangzhou presents the characteristics of a circle layered structure， which is composed of the comprehensive recreational belt around the city within 20 km， the secondary comprehensive recreational belt between 20 and 40 km， the suburban recreational belt between 40 and 70 km， and the exurb vacation belt over 70 km； （2） many types of recreational resources exist in the recreational belt around the metropolis of Guangzhou city， and the spatial distribution and agglomeration patterns differ significantly by types； and （3） the densely distributed recreation areas were identified by administrative border as comprehensive recreation areas of Panyu and that of Baiyun district， secondary comprehensive recreation areas of Huangpu district and Huadu district， ecological recreation area of Zengcheng， hot spring vacation recreation area of Conghua district and seaside recreation area of Nansha district.关键词：recreational belt around metropolis;spatial characteristics;Guangzhou;POI
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发布时间：2023-11-01 - 摘要：A lithium-ion diffusion-stress coupling model in the form of a tensor in three-dimensional rectangular coordinates was established using the constitutive equation constructed by the finite deformation theory and the diffusion-induced stress hypothesis. Combined with the K criterion in fracture theory， the expansion of crack is determined by using the finite element method. The model is applied to the column electrodes and spherical electrodes， where three-dimensional cracks are added to study the relationship between stress strength factors and crack size. Combined with the fracture toughness of the material， the critical size of crack propagation is obtained. Cracks in the electrode that are longer than the critical size will expand， cracks in the column electrode developing in axial direction will continue to expand until they run through， cracks along radial development will gradually stabilize and will not run through， and cracks in the spherical electrode will gradually stabilize， depending on the size of the electrode. The 3D model is not limited to axis symmetry， but is suitable for particle electrodes containing any form of defect， which is of general significance， and the results can make optimization recommendations for the screening of particle electrode internal defects.关键词：Lithium battery;diffusion induced stress;crack propagation;K criterion
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发布时间：2023-11-01 - 摘要：Lattice Boltzmann Method （LBM） is a kind of widely used mesoscopic fluid numerical simulation method. The drawback of LBM is the high computational cost， which causes difficulties in real-time simulation. In this work， we created a convolutional neural network （CNN） based on U-Net to accelerate LBM calculation. The purpose is to replace multiple LBM steps with one single operation of the CNN model. According to the result of our numerical experiment on a laminar flow around three obstacles in different geometries， the generated model can maintain the calculation at a high accuracy and accelerate the LBM calculation by over 250 times.关键词：data-driven modeling;Lattice Boltzmann Method;convolutional neural network;neural network architecture;surrogate model
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发布时间：2023-11-01 - 摘要：The time finite element method is used to solve structural dynamics because of its strict prior error bounds and the characteristics of calculation error do not spreading over time. This paper mainly analyzes the algorithm stability and period elongation of the time finite element method. The stability of the algorithm is controlled by the spectral radius of the time finite element transfer matrix. When the spectral radius is less than 1， the time finite element has long-term stability. The period elongation is the relative error between the calculation period and the theoretical period. The larger the value， the higher the unpredictability of the long-term response. The analysis results show that for a damped system（damping ratio is greater than 0.05%）， when the time step is less than the period， the spectral radius of the algorithm is less than 1. For undamped systems（or damping ratio is less than 0.05%）， when the time step is less than 0.3 times of the period， the algorithm is conditionally stable. On the other hand， the period elongation of the algorithm is almost 0， which means that the calculation of time finite element will not cause period drift. Finally， the application of the time finite element to the dynamic analysis of the beam verifies the advantages of the algorithm in accuracy.关键词：time finite element;analysis of stability;period elongation
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发布时间：2023-11-01 - 摘要：For structural damage identification， model errors brought by the simplification of shear structure will often have bad effects on the result. To alleviate the errors， the modal measurement changes correction strategy is proposed. And because of the sparsity of damage itself， sparse regularization is invoked to solve the ill-posedness of damage identification that is an inverse problem. Moreover， in order to reduce the extra computational cost caused by sparse regularization， a new objective function is established accordingly， and the alternate optimization method is used to get the solution. The accuracy of the identification method present here are verified by identifying the SHM Benchmark problem. Additionally， a significant advantage of the modal measurement changes correction strategy has been shown.That is， only the number of floors is required to detect damage， which extremely suitable for the damage identification of real multi-story buildings whose actual mass and stiffness are hard to obtain.关键词：damage identification;shear structure;modal measurement changes;sparse regularization;alternate optimization method
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发布时间：2023-11-01 - 摘要：Based on first order cnoidal wave diffraction theory， the wave field analytical solutions to shallow water wave diffraction by a inscribed circular cylinder with double-layered arc-shaped porous thin walls with different central angles are derived. By calculating the maximum wave forces on the structure and maximum diffracted wave surfaces，the cnoidal wave diffraction law has been revealed. The results demonstrate that the double arc-shaped outer thin wall can greatly reduce wave effects on inscribed circular cylinder and the variation of wave and sea water condition. Various geometry conditions of double outer thin wall and cylinder ， the porous coefficients of structure may have some influence on cnoidal wave effects. In certain shallow water conditions， the maximum wave effects from cnoidal wave theory are larger than those predicted by small amplitude wave theory. Practical maximum wave forces on structure will increase as the shallow water wave characteristic parameter value increases.关键词：cnoidal wave;eigenfunction expansion method;diffraction;wave surface;wave force
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发布时间：2023-11-01 - 摘要：A set of vehicle mobility information extraction and urban road usage characteristics analysis framework is proposed based on automatic vehicle identification data and Gini coefficient theory. First of all， we perform the reconstruction of individual mobility information of whole-network vehicles to obtain the OD， path and travel time of all vehicles per trip， and then collect the travel demand of the road； secondly， we construct the model of the Gini coefficient evaluation of road usage and propose average division point of vehicle mobility distribution based on Lorenz curve； finally， taking the automatic identification data of Xuancheng city， Anhui Province as an example， the spatial and temporal characteristics analysis of urban road usage and the classification of road usage patterns were carried out. The results show that the method in this paper can quantifiably evaluate the functions and roles of different roads perfectly.关键词：intelligent traffic;road usage pattern;Gini coefficient;urban roads;automatic vehicle identification data;traffic management
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发布时间：2023-11-01 - 摘要：Single particle aerosol mass spectrometer （SPAMS） can provide real-time， continuous and high time resolution data about the size and chemical composition of single particles. The reliable qualitative capability of SPAMS has been widely used to determine the mixing state of atmospheric fine particles. However， the quantitative ability of SPAMS has not been fully evaluated. In this study， the measurement of SPAMS combined with filter sampling was used to conduct the quantitative evaluation of SPAMS in Zhengzhou from December 1， 2017 to February 28， 2018. The peak area and number concentration of elemental carbon (EC)， organic carbon (OC)， sulfate， nitrate and ammonium containing single particles were compared with the mass concentration measured by the filter membrane， and the regression analysis coefficient
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发布时间：2023-11-01 - 摘要：145 accidents with videos were reconstructed by PC-Crash firstly， and then the vehicle braking is adjusted to prolong the pedestrian-vehicle interaction time in each case， finally parameters such as pedestrian throw distance， pedestrian injury and the interaction time were collected and analyzed by graphing and statistical method. Results shown that there is a significant negative correlation between the pedestrian-vehicle interaction time and the ground related injury； the ground related injury of the head， the pelvis and the torso （when the impact speed ≥40 km/h） can be reduced significantly by prolonging the interaction time； the ground related injury of four limbs and vehicle related injury of head， torso and pelvis will not change obviously when the interaction time were prolonged. This indicates that new approaches for protecting the ground related injury can be explored from the perspective of the pedestrian-vehicle interaction time.关键词：pedestrian-ground contact;interaction time;PC-Crash;accident reconstruction
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发布时间：2023-11-01 - 摘要：The echolocation signal of odontocetes has the characteristics of high-frequency and high-directivity， which enables it to accurately sense underwater targets and is the object imitated by modern sonar. In this paper， by analyzing the geometric structure and tissue characteristics of the head of the pygmy sperm whale （Kogia breviceps）， the hyperbolic secant refractive index material is used to simulate the melon with continuous changing sound velocity， and the contour of the melon is modeled by the outermost sound track of the hyperbolic secant refractive index material. In frequency domain and time domain， the far-field directivity of the simulation model is analyzed by finite element method. The results show that the plane wave is formed at the opening after the point source passes through the melon with hyperbolic secant gradient refractive index， that is， the melon has the function of collimation. By analyzing the correlation of far-field sound pressure values in different regions， it is shown that the collimation of the melon is the main reason for the formation of the narrower main lobe while the air sacs and the skull mainly play the role of suppressing the side lobe.关键词：pygmy sperm whale （Kogia breviceps）;high-directivity;gradient index;collimation
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发布时间：2023-11-01 - 摘要：It is difficult to simulate the response of aeroelastic system directly because of the convolution integral in the unsteady Theodorsen aerodynamic force. To the best of our knowledge， there are three different ways to deal with the integral operator， so that the simplified equation only contains the differential operators. Despite huge applications of these models， the equivalence relationship among them is still less studied. In this paper， we will prove mathematically proved that the three simplified models are equivalent， and verify them by Runge-Kutta method and precise integration method， respectively. Numerical results show that these models exhibit exactly the same solutions for both transient and steady responses.关键词：airfoil;aeroelastic system;state space model;equivalence
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发布时间：2023-11-01 - 摘要：The transmission eigenvalue problems in inverse scattering of penetrable inhomogeneous media is studied by using a boundary integral equation method.Firstly，the Robin-Dirichlet operator is constructed from the transmission eigenvalue problems in inverse scattering of penetrable inhomogeneous media，and the Robin-Dirichlet operator is represented by the boundary integral operator.Secondly，the coerciveness of an operator is proved by the Green's formula，Fredholm alternative and the trace theorem.Thirdly，the compact embedding theorem and Lax-Milgram theorem are applied to prove the compactness of another operator.Finally，combining the properties of the two operators，it is proved that the difference operator of the Robin-Dirichlet operator is an analytic Fredholm operator whose exponent is 0.关键词：a boundary integral equation method;transmission eigenvalue problems;Robin-Dirichlet operator;Fredholm operator
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发布时间：2023-11-01
Research articles
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