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Epileptic networks are characterized as having two states, seizures or more prolonged interictal periods. However, cellular mechanisms underlying the contribution of interictal periods to ictal events remain unclear. Here, we use an activity-dependent labeling technique combined with genetically encoded effectors to characterize and manipulate neuronal ensembles recruited by focal seizures (FS-Ens) and interictal periods (IP-Ens) in piriform cortex, a region that plays a key role in seizure generation. Ca2+ activities and histological evidence reveal a disjointed correlation between the two ensembles during FS dynamics. Optogenetic activation of FS-Ens promotes further seizure development, while IP-Ens protects against it. Interestingly, both ensembles are functionally involved in generalized seizures (GS) due to circuit rearrangement. IP-Ens bidirectionally modulates FS but not GS by controlling coherence with hippocampus. This study indicates that the interictal state may represent a seizure-preventing environment, and the interictal-activated ensemble may serve as a potential therapeutic target for epilepsy. [Display omitted] • FS-Ens and IP-Ens show a dissociated calcium activity during FS dynamics • Optogenetic activation of FS-Ens promotes seizure development, while IP-Ens retards it • FS-Ens and IP-Ens are both involved in GS due to circuit rearrangement • IP-Ens protects against FS but not GS by controlling its coherence with the hippocampus The cellular mechanisms underlying the contribution of interictal period to ictal events remain unclear. By using activity-dependent labeling techniques combined with genetically encoded effectors, Lai et al. show that interictal-activated ensembles in piriform cortex retard seizure development via modulating oscillatory coherence, indicating that interictal state may represent a seizure-preventing environment. [ABSTRACT FROM AUTHOR]

Highlights: [•] A facile approach of preparing Ag NPs/porous silicon (PSi) chip is described. [•] The principle of forming Ag NPs on PSi surface is discussed in detail. [•] The Ag NPs/PSi chip performs well in catalytic reduction of aromatic nitro groups. [Copyright &y& Elsevier]

Abstract: The configuration sizes of multi-layer microchannel heat sink is optimized in order to enhance the performance of the high flux chip, which is 556W/cm2. Taking the thermal resistance and the pressure drop as goal functions, a double-objective optimization model was proposed based on the thermal resistance network model. The opimized microchannel heat sink is numerically simulated by computational fluid dynamics (CFD) software. The number of microchannel in width n1 and that in height n2 are 24 and 2, the width of optimized optimized microchannel and fin are 196 and 50μm, respectively, and the corresponding total thermal resistance of the whole microchannel heat sink is 0.4025°C/W. The highest temperature is less than 98°C, which can satisfy the requirement of chip to temperature. The maximum temperature difference is 77.8673°C, and the transferred power of heat flux is 200W, so the total thermal resistance is 0.3893°C/W, which agrees well with the analysis result of thermal resistance network model. [Copyright &y& Elsevier]

Abstract: Heat treatment is one method to improve mechanical properties of metal, but each heat treatment method has its advantages and disadvantages, therefore, different requirements regarding size, shape, and properties with respect to different heat treatment processes should be considered. The traditional liquid quenchant are clear water and quench oil. Gas quenching is a relatively new process with several important advantages, such as minimal environmental impact, clean products, and ability to control the cooling locally and temporally for best product properties. To meet the high cooling rates required for quenching, the cooling gas must flow at very high velocities, but still the cooling capacity of gas is weakness. In order to increase the cooling capacity of gas, the spray water is added during gas quenching. In this paper, the GCr15 steel is as the research object, the cooling capacity of clear water, quench oil, nitrogen and nitrogen-spray water are studied through comparison of temperature difference and cooling velocity of the specimen. [Copyright &y& Elsevier]

Abstract: Heat treatment is one method to improve mechanical properties of metal, but each heat treatment method has its advantages and disadvantages, therefore, different requirements regarding size, shape, and properties with respect to different heat treatment processes should be considered. Gas quenching is a relatively new process with several important advantages, such as minimal environmental impact, clean products, and ability to control the cooling locally and temporally for best product properties. To meet the high cooling rates required for quenching, the cooling gas must flow at very high velocities. The phase transformation will occur during quenching. The phase composition will influence the mechanical properties of metal. Consequently, the computation of phase composition is important for the mechanical properties of metal after quenching. In this paper, the mathematical model of phase composition computation was created based on phase transformation kinetics, The phase composition of T10 steel during gas quenching was calculated. [Copyright &y& Elsevier]

Abstract: The project involved in this paper is a single-tower double-cable-plane bridge, and the gulf nearby the bridge is in a typical typhoon-affected zone. Therefore, modal analysis of the cable-stayed bridge should be carried out. In this paper, based on the structural vibration theory and the theory of finite element model (FEM) , the space FEM model of the cable-stayed bridge are established with APDL — ANSYS Parametric Design Language. Vibration mode and its frequency can be concluded by the calculating of the cable-stayed bridge''s FEM model. [Copyright &y& Elsevier]

Abstract: The stress strain at notch root of round specimen with material property gradient were analysed with elasto-plastic finite element analysis, based on the hardness value obtained from spot welds heat affect zone. Material cyclic strength and fatigue strength coefficient are assumed to be proportional to hardness distribution according Eleiche''s conclusion. A set of finite element models was established with material gradient, notches in each model were in different material zone. Elasto-plastic analyses were carried for notch stress strain distribution under different loading levels. Material gradient on life prediction were analysed with local stress strain approach. [Copyright &y& Elsevier]

In numerical simulation of quenching process, the boundary conditions of temperature field and stress field are very important, in which the boundary conditions of temperature field are very complicated. In order to simulate the thermal strains, thermal stresses, residual stresses and microstructure of the steel during gas quenching by means of the numerical method, it is necessary to obtain an accurate boundary condition of temperature field. The surface heat-transfer coefficient is a key parameter. The explicit finite difference method, non-linear estimate method and the experimental relation between temperature and time during quenching have been used to solve the inverse problem of heat conduction. The relationships between surface temperature and surface heat-transfer coefficient of cylinder have been given. The non-linear surface heat-transfer coefficients include the coupled effects between phase transformation and temperature. In calculation, physical properties were treated as the function of temperature and volume fraction of constituent. The results obtained have been shown that this technique can determine effectual the surface heat-transfer coefficients during gas quenching. [Copyright &y& Elsevier]

Highlights • Extension to VCFEM is achieved through enhancements in stress functions. • A singular Voronoi cell finite element method is proposed. • Stress intensity factors of crack-tip are calculated using the least square method. • Validation of this model shows good improvement. Abstract In this paper, a new singular Voronoi cell finite element method (S-VCFEM) is proposed to study the initiation and propagation of interfacial debonding and matrix cracking in particulate reinforced composite. Composites with large-scale inclusions and cracks can be easily simulated with this model. A new assumed stress hybrid variational functional is derived from the element energy function to accommodate the interface traction reciprocity on bonded interface and the interface traction-free on debonded interface and matrix crack surface. S-VCFEM is achieved through enhancements in stress functions in the assumed stress hybrid formulation. In addition to polynomial terms and interaction terms, singular stress terms of Williams expansion are added for stress functions, which are adaptively enriched to accurately capture the crack-tip stress concentrations. After obtaining the stress field, calculation of stress intensity factors is performed, using the least square method based on stress value obtained numerically in the S-VCFEM. The efficiency of the method is verified against numerical results obtained by ABAQUS with XFEM module for the same problem considering a matrix-crack and a debonded interface. [ABSTRACT FROM AUTHOR]

A generalized method for calculating the stress intensity factor from angular deflection of light rays is proposed. The method is based on 2D digital image correlation (DIC) to measure angular deflection of light rays, however, when a specimen is subjected to loading, deformation measurement from DIC is not perfect because of the existence of small in-plane and out-of-plane motions of the test sample surface that occurred after loading. These disadvantages will lead to errors in the measured angular deflections and fracture parameters. The influence of unavoidable in-plane and out-of-plane motions is discussed, and a generalized method to eliminate them to show the pure stress gradient of the crack tip of Polymethyl Methacrylate (PMMA) is demonstrated. At the same time, the fracture parameter of stress intensity was calculated. The experimental angular deflection of light rays was compared with the theoretical angular deflection predicted by generalized model using data points in an array around the crack tip region. To show the potential and efficacy of the method, K values were obtained from experimental data during tests conducted in a PMMA three-point-bend specimen. Results show an excellent level of agreement with K values predicted from FEM, highlighting the potential of the proposed methodology. [ABSTRACT FROM AUTHOR]

• Extension to VCFEM is achieved through enhancements in stress functions. • A new X-VCFEM is proposed to model the interface and matrix cracking in composites. • The matrix crack propagation is determined by the maximum energy release rate. • The interface crack propagation is assessed on the base of a series of criteria. • A remeshing algorithm is constructed. In this paper, a new extended Voronoi cell finite element method (X-VCFEM), in which two new elements in the crack propagation process are proposed and a remeshing algorithm is constructed, is proposed to model the initiation and propagation of the interface crack and the matrix crack in particulate reinforced composites. In order to accurately capture crack-tip stress concentrations, some singular stress terms of Williams expansion in the vicinity of crack tips are introduced in the stress functions in X-VCFEM. The direction of the crack propagation in matrix is determined by the maximum energy release rate and the interface crack propagation along the interface or into the matrix is assessed on the base of a series of criteria relating to the critical normal stress and the critical hoop stress. Then several numerical examples are used to demonstrate the effectiveness of X-VCFEM by comparing with results obtained by the commercial software ABAQUS. At last, a numerical example is given for a complex structure with 20 randomly distributing inclusions to model the interfacial cracking and matrix cracking. It is certain that this method is a powerful way to model the interfacial and matrix damage of composites containing a great deal of inclusions and cracks. [ABSTRACT FROM AUTHOR]

• Extension to VCFEM is achieved through enhancements in stress functions. • A new extended Voronoi cell finite element method is proposed. • The direction of the crack propagation is adaptively determined in terms of the maximum energy release rate. • A remeshing strategy is constructed. • The propagation of multiple cracks in brittle materials is simulated. This paper introduces a new extended Voronoi cell finite-element method (X-VCFEM) for modelling the propagation of multiple cracks in brittle materials. The direction of the crack propagation is adaptively determined in terms of the maximum energy release rate near the crack tip, and we apply a remeshing strategy that a node at a last incremental crack tip in the crack advance process is replaced by a node pairs to realize the gradual crack propagation. In order to accurately capture crack-tip stress concentrations, some singular stress terms of Williams expansion in the vicinity of crack tips are introduced in the assumed stress hybrid formulation which also includes the polynomial terms and the reciprocal terms. Then several numerical examples are used to demonstrate the effectiveness and accuracy of X-VCFEM enriched by some singular stress terms of Williams expansion by comparing X-VCFEM results with those computed by the commercial finite element package ABAQUS or established results in the literature. At last, two numerical examples are given to simulate multiple crack propagation in brittle media. The effects of morphological distributions such as length, orientation and dispersion on the crack propagation are studied. It is obvious that the X-VCFEM has great advantage of analyzing large regions of the microstructure with multiple growing and interacting cracks. [ABSTRACT FROM AUTHOR]

Previous studies indicated the involvement of cholinergic neurons in seizure; however, the specific role of the medial septum (MS)-hippocampus cholinergic circuit in temporal lobe epilepsy (TLE) has not yet been completely elucidated. In the current study, we used magnetic resonance imaging and diffusion tensor imaging to characterize the pathological change of the MS-hippocampus circuit in 42 patients with TLE compared with 22 healthy volunteers. Using optogenetics and chemogenetics, combined with in vivo or in vitro electrophysiology and retrograde rabies virus tracing, we revealed a direct MS-hippocampus cholinergic circuit that potently attenuates seizure through driving somatostatin inhibition in animal TLE models. We found that patients with TLE with hippocampal sclerosis showed a decrease of neuronal fiber connectivity of the MS-hippocampus compared with healthy people. In the mouse TLE model, MS cholinergic neurons ceased firing during hippocampal seizures. Optogenetic and chemogenetic activation of MS cholinergic neurons (but not glutamatergic or GABAergic [gamma-aminobutyric acidergic] neurons) significantly attenuated hippocampal seizures, while specific inhibition promoted hippocampal seizures. Electrophysiology combined with modified rabies virus tracing studies showed that direct (but not indirect) MS-hippocampal cholinergic projections mediated the antiseizure effect by preferentially targeting hippocampal GABAergic neurons. Furthermore, chemogenetic inhibition of hippocampal somatostatin-positive (rather than parvalbumin-positive) subtype of GABAergic neurons reversed the antiseizure effect of the MS-hippocampus cholinergic circuit, which was mimicked by activating somatostatin-positive neurons. These findings underscore the notable antiseizure role of the direct cholinergic MS-hippocampus circuit in TLE through driving the downstream somatostatin effector. This may provide a better understanding of the changes of the seizure circuit and the precise spatiotemporal control of epilepsy. [ABSTRACT FROM AUTHOR]

In this paper, a simultaneous measurement method of stress-optic constant and stress field of transparent plate is presented based on digital holographic interferometry. An image-plane digital holographic system is used to capture holograms and measure phase difference of object wave at different loading states. The relationship among the phase difference, the stress-optic constant and stress of transparent plate is given. The stress-optic constant and stress field of a polymethyl methacrylate (PMMA) specimen with a hole under uniform tensile force are measured by this method. The experimental results are in accordance with the existed and theoretical ones. [ABSTRACT FROM AUTHOR]