Search

How to ensure the safety of occupants has become a challenge for protective design of armored vehicles against intensive blast loadings. In this study, for armored vehicles subjected to shallow-buried explosions, an analytical model was established to characterize the dynamic performance of an all-metallic sandwich floorboard attached with a double mass-spring-damping system (mimicking seat and occupant), with the former consisting of a front face, a core and a rear face. For validation, numerical simulations with the method of finite elements (FE) were performed. Good agreement between analytical predictions and numerical results was achieved.The analytical model was then employed to quantify the effects of explosive mass, yield stress of material make, configurational parameters of sandwich panel, spring stiffness, and damping coefficient on dynamic response of the sandwich panel and double mass-spring-damping system. With increasing explosive mass and decreasing yield stress of material make, the peak displacements of rear face, seat and occupant were all found to increase. As core relative density was increased, these peak displacements also increased when the ratio of face thickness to core height was relatively small. Increasing the ratio of face thickness to core height led to increased peak accelerations of seat and occupant. The peak displacement of rear face was insensitive to the increase of either spring stiffness or damping coefficient, while the peak acceleration of occupant increased with increasing spring stiffness. Upon increasing the damping coefficient between the rear face and seat or that between the seat and occupant or both, the peak acceleration of occupant increased. With occupant safety duly considered, the proposed analytical model provides useful guidance for designing high-performance protective structures for armored vehicles subjected to intensive blast loadings. [ABSTRACT FROM AUTHOR]

The high energy particles in the space environment will perturb integrated circuits, resulting in system errors or even failures, which is also known as single event effects (SEE). To ensure the normal operation of space systems, it is first necessary to detect these errors. However, detection algorithms also bring additional overhead to the system and reduce its performance. Therefore, we aim to find a trade-off between reliability and performance. To this end, we propose a quantitative evaluation model for detection methods that evaluates the reliability gain of different detection methods under the same overhead. Our method allocates the optimal detection method to the corresponding code segment based on the quantitative results, thereby achieving a trade-off between reliability and performance. Experimental results show that the average energy efficiency of our trade-off method is 91.34%, which is 21.49% higher than the other methods. [ABSTRACT FROM AUTHOR]

Carbon control in the thermal power generation industry is crucial for achieving the overall carbon peak target. How to predict, evaluate, and balance the allocation of inter provincial carbon emissions has a significant impact on the decision-making of reasonable allocation of inter provincial carbon emissions in the target year. Therefore, this paper uses Monte Carlo-ARIMA-BP neural network and ZSG-DEA model to conduct temporal trend prediction and carbon emission quota allocation research. We propose the "intra provincial and inter provincial" framework for carbon emissions trading in thermal power plants, which aims to break through the barriers in carbon emission rights exchange among provinces. The conclusions are as follows: (1) the growth trend of carbon emissions from thermal power is gradually slowing down and is expected to peak before 2030. (2) Inner Mongolia, Jiangsu, and Shandong have high input–output efficiency, and are all the main output provinces for carbon emission quota allocation. After being adjusted using the ZSG-DEA model, they can still be at the forefront of efficiency. (3) The "intra provincial and inter provincial" framework for carbon emissions trading can effectively predict and allocate the carbon emission demand of each province from time and space dimensions, balance the carbon emission rights and interests of each province, and provide forward-looking planning suggestions for inter provincial carbon emission rights exchange. [ABSTRACT FROM AUTHOR]

Previous scientific research on reservoirs of the Deng IV Member in the Gaoshiti-Moxi area, the main production area of the Anyue gas field with reserves of tens of billions of cubic metres, has focused on karst palaeogeomorphology reconstruction, the facies distribution on platform margins, and their effects on creating favourable reservoirs. However, the quality of microbial carbonate reservoirs is also closely related to their original depositional environments on both inner and marginal platforms. Therefore, this paper attempts to reveal favourable microbial carbonate reservoir characteristics and the sedimentary effects on their distribution and prediction based predominantly on a synthetic analysis of the sequence stratigraphy and depositional facies. The results show that favourable reservoirs of the Deng IV Member are classified into three types according to their reservoir spaces: fracture-cavity, pore-cavity and pore reservoirs. Secondary dissolution pores and cavities are primary reservoir spaces developed mainly in nonskeletal grain dolomites with sparry cements, thrombolites, and stromatolites. The physical properties of the fracture-cavity and pore-cavity types of reservoirs are better than those of pore reservoirs and have porosities between 1 and 5% and permeabilities between 0.01 × 10–3 and 1 × 10–3 μm2. Vertically, favourable reservoirs are developed mainly in parasequence set 6 (PSS6) and PSS7 and are laterally distributed in well zone MX9-MX19-MX1 for the fracture-cavity type, MX105-MX110-GS20 for the pore-cavity type and MX17-MX107-MX41-MX102-GS102 for the pore type. Moreover, depositional effects on reservoirs in terms of depositional sequences, seismic facies, microfacies and microfacies associations indicate that to some extent, the fracture-cavity type of reservoir is constrained by the top boundaries of PSS7, PSS2, parasequence 17 (PS17) and PS14; the pore-cavity type of reservoir is constrained by the top boundaries of PSS7, PSS4, PS18 and PS12; and the pore type of reservoir is constrained by the top boundaries of PSS7, PSS6, PSS3, PSS2, PS18, PS17, PS14, and PS12. Seismic facies associated with shoals and mound-flat complexes are related to the facies distributions of pore cavities and pore reservoirs. MA1, MA3, MA7, and MA8 are predominant microfacies associations of favourable reservoirs of the Deng IV Member in the Gaoshiti-Moxi area. The above results are significant for further petroleum exploration and exploitation of ultradeep microbial carbonate reservoirs in this area. [ABSTRACT FROM AUTHOR]

The proposal of "double carbon" goal increases the pressure of power structure transformation. This paper sets up two scenarios according to the timing progress of realizing the "double carbon" goal and explores the transformation planning schemes of China's power structure. The conclusions are as follows: (1) Technological progress and policy support will greatly reduce the levelized cost of electricity (LCOE) of onshore wind power, offshore wind power, photovoltaic power, and photothermal power. The rapid rise in carbon price will lead to the LCOE of coal power in 2060 rising to 2 CNY/kWh. (2) The power consumption of the whole society in the baseline scenario can reach 17,000 TWh in 2060. In the acceleration scenario, this value may triple that in 2020 to 21,550 TWh. (3) The acceleration scenario will pay more newly added power costs and coal power stranded scale than the baseline scenario but can achieve carbon peak and negative emissions earlier. (4) More attention should be paid to the flexible level of power system, improve the allocation proportion and requirements of new energy storage on the power supply side, help the steady exit of coal power, and ensure the safety of low-carbon transformation of power structure. [ABSTRACT FROM AUTHOR]

Chronic inflammation and dyslipidemia are important risk factors in developing atherosclerotic cardiovascular disease, such as coronary heart disease. Acute coronary syndrome (ACS) is one of the most dangerous syndromes in coronary heart disease. Type 2 diabetes mellitus (T2DM) is considered equal to coronary heart disease owing to the high cardiac risk induced by chronic inflammation and dyslipidemia. The neutrophil to high-density lipoprotein cholesterol ratio (NHR) is a novel and straightforward marker that reflects inflammation and lipid metabolic disorder. However, few studies have been on the role of NHR in assessing the risk of ACS in T2DM patients. Here we analyzed NHR level in ACS patients with T2DM, exploring its predictive and diagnostic values. 211 hospitalized ACS patients with T2DM were recruited as the case group, and 168 hospitalized T2DM patients as the control group (all patients collected from 6/2020 to 12/2021 in Xiangya Hospital). Biochemical test results and echocardiograms, as well as demographic information such as age, BMI, diabetes mellitus, smoking, drinking, and history of hypertension, were recorded. Frequencies, percentages, means, and standard deviations were used to describe the data. The shapiro–Wilk test was used to assess the normality of the data. Normally distributed data were compared using the independent sample T-test, and non-normally distributed data were compared using Mann–Whitney U test. Correlation analysis was performed using the Spearman rank correlation test, and receiver operating characteristic (ROC) curve analysis and multivariable logistic regression analysis were performed by SPSS version 24.0 (SPSS Inc) and GraphPad Prism 9.0 (GraphPad Software Inc). p < 0.05 was considered significant. In the study population, NHR was higher in patients with T2DM combined with ACS than in T2DM patients without ACS (p < 0.001). After adjusting for BMI, alcohol consumption, and history of hypertension, multifactorial logistic regression analysis revealed that NHR is a risk factor for T2DM patients combined with ACS (OR 1.221, p = 0.0126). Correlation analysis on all ACS patients with T2DM showed that NHR level was positively correlated with cTnI (r = 0.437, p < 0.001), CK (r = 0.258, p = 0.001), CK-Mb (r = 0.447, p < 0.001), LDH (r = 384, p < 0.001), Mb (r = 0.320, p < 0.001), LA (r = 0.168, p = 0.042) and LV levels (r = 0.283, p = 0.001). And meanwhile, NHR level was negatively correlated with EF (r = − 0.327, p < 0.001) and FS levels (r = − 0.347, p < 0.001). ROC curve analysis showed that NHR ≧ 4.32 had a sensitivity of 65.45% and a specificity of 66.19% for predicting ACS in T2DM patients [area under the curve (AUC) = 0.722, p < 0.001]. Furthermore, in all ACS patients with T2DM, the diagnostic power of NHR was stronger in ST-segment elevated ACS patients (STE-ACS) than that in non-ST-segment elevated ACS patients (NSTE-ACS) (p < 0.001). With its convenience and effective character, NHR could be a potential and new marker for predicting the presence, progression, and severity of ACS in T2DM population. [ABSTRACT FROM AUTHOR]

In this study, a numerical model of the plasma expansion on a droplet surface based on the initial plasma method was proposed. The initial plasma was obtained through the pressure inlet boundary condition, and the effect of ambient pressure on the initial plasma and adiabatic expansion of the plasma on the droplet surface, including the effect on the velocity and temperature distribution, were investigated. The simulation results showed that the ambient pressure decreased, leading to an increase in the expansion rate and temperature, and therefore a larger plasma size was formed. Plasma expansion creates a backward driving force and eventually envelops the entire droplet, indicating a significant difference compared to planar targets. [ABSTRACT FROM AUTHOR]

This work experimentally investigates and compares terahertz electromagnetic shielding of micrometer-thick Ti3C2Tx MXene on polyimide prepared by two methods: etched using LiF/HF or HCl/HF from the MAX phase precursor. The later process shows a larger absorption coefficient as well as higher electrical conductivity. Raman spectroscopy and scanning electron microscopy are employed to probe the Tx termination, as well as, the structure of Ti3C2Tx MXene layer. It is found that the degree of oxygen termination resulting from the type of etchant play a significant role in bridging nearby titanium between the Ti3C2Tx MXene flakes. This is observed to increase the continuity of the Ti3C2Tx MXene surface and substantially enhances terahertz radiation shielding. [ABSTRACT FROM AUTHOR]

The insufficient of H2O2 restricts the efficacy of chemodynamic therapy in tumor microenvironment. Calcium peroxide (CaO2) is expected to solve this problem due to its H2O2-evolving ability. However, it prematurely decomposes in the moist air or water before reaching tumor site. In this study, zeolitic imidazolate framework-67 (ZIF-67) was in-situ grown on the surface of CaO2 to construct a pH-responsive CaO2@ZIF-67 system and then incorporated into poly-L-lactic acid (PLLA) to prepare PLLA/CaO2@ZIF-67 scaffold by selective laser sintering technology. On the one hand, ZIF-67 is used as a chemodynamic therapy agent due to the release of cobalt ions after degradation. On the other hand, ZIF-67 can serve as protective layers to prevent premature decomposition of CaO2 due to its hydrophobic properties, and then CaO2 is exposed and reacts with water to form H2O2 after the pH-responsive degradation of ZIF-67 under tumor acidic microenvironment. Results showed that the PLLA/CaO2@ZIF-67 scaffold could sustainedly produce H2O2 under acidic pH and achieve 84.64% antitumor ratio against MG-63 cells. In addition, the scaffold also promoted proliferation and osteogenic differentiation of mouse bone marrow mesenchymal stem cells due to the release of calcium ions. The prepared PLLA/CaO2@ZIF-67 scaffold with chemodynamic antitumor and osteogenic effects has great potential to treat tumorous bone defect. [ABSTRACT FROM AUTHOR]

Traditional centralized cloud storage has difficulties in realizing the secure storage and sharing of speech and other multimedia data, as well as realizing fine-grained access control and privacy protection for speech data. To address this problem, we propose a distributed storage scheme for encryption speech data based on blockchain and inter planetary file system (IPFS). Our scheme is based on the characteristics of blockchain anti-tampering, decentralization and traceability. It is designed to ensure the security and controllability of private sensitive speech data of data users without the use of centralized cloud storage architecture. First, the ciphertext policy hierarchical attribute-based encryption (CP-HABE) scheme is used to encrypt the speech data. The encrypted speech data is then stored in the IPFS to achieve distributed storage. Second, a distributed and trusted access control policy is implemented by deploying an access control protocol Ethereum smart contract related to speech attributes. Finally, the proposed scheme is deployed and tested in the Linux environment, and the smart contract is deployed on the Ethereum test chain. Through experimental comparison with different storage schemes, analysis of the operational properties of our scheme and the evaluation of the quality index of the encryption scheme, the proposed scheme is shown to reliable, secure and scalable. [ABSTRACT FROM AUTHOR]

When subjected to localized blast loading from shallow-buried explosives (e.g., mines buried under sand), how would a sandwich structure dynamically perform has been extensively investigated, both experimentally and numerically, but not analytically. This study aimed therefore to establish an analytical model for preliminary assessment of using sandwich panels with square honeycomb cores for protective applications against shallow-buried explosions, with the influence of boundary conditions (e.g., simply supported versus fully clamped) accounted for. The resulting maximum permanent deflection of the sandwich panel was expressed as an explicit function of explosive mass, sand density, sand moisture content, depth of burial, stand-off distance as well as key sandwich panel geometrical parameters. For validation, the model predictions were compared with existing experimental measurements as well as numerical results obtained with the method of finite elements, with good agreement achieved. The validated analytical model was subsequently employed to quantify the effects of various influencing factors. The maximum deflection was found to increase with increasing explosive mass, sand density, and sand moisture content, but with decreasing stand-off distance. As the height of core was increased, the maximum deflection decreased firstly and then increased, suggesting that selecting a proper core height was critical in the design of sandwich panel constructions for optimal blast resistance. Regardless of boundary conditions, an intersection point existed between the normalize deflection versus normalized impulse curves that correspond separately to the sandwich panel and its monolithic counterpart of equal mass. When the normalized impulse had a magnitude smaller than the intersection value, the sandwich panel exhibited a superior blast resistance to the monolithic one, while the opposite held when the normalized impulse was located to the right of intersection. The normalized impulse corresponding to the intersection was dependent upon face sheet thickness, core height, and core relative density. The proposed analytical model provides valuable guidance for designing high-performance protective structures against intensive impulsive loadings. [ABSTRACT FROM AUTHOR]

Background: This study aimed to develop a novel analytic approach based on a radiomics model derived from 68Ga-prostate-specific membrane antigen (PSMA)-11 PET/CT for predicting intraprostatic lesions in patients with prostate cancer (PCa). Methods: This retrospective study included consecutive patients with or without PCa who underwent surgery or biopsy after 68Ga-PSMA-11 PET/CT. A total of 944 radiomics features were extracted from the images. A radiomics model was constructed using the least absolute shrinkage and selection operator (LASSO) algorithm with tenfold cross-validation in the training set. PET/CT images for the test set were reviewed by experienced nuclear medicine radiologists. The sensitivity, specificity, positive predictive value, negative predictive value, and area under the receiver operating characteristic curve (AUC) were calculated for the model and radiologists' results. The AUCs were compared. Results: The total of 125 patients (86 PCa, 39 benign prostate disease [BPD]) included 87 (61 PCa, 26 BPD) in the training set and 38 (61 PCa, 26 BPD) in the test set. Nine features were selected to construct the radiomics model. The model score differed between PCa and BPD in the training and test sets (both P < 0.001). In the test set, the radiomics model performed better than the radiologists' assessment (AUC, 0.85 [95% confidence interval 0.73, 0.97] vs. 0.63 [0.47, 0.79]; P = 0.036) and showed higher sensitivity (model vs radiologists, 0.84 [0.63, 0.95] vs. 0.74 [0.53, 0.88]; P = 0.002). Conclusion: Radiomics analysis based on 68Ga-PSMA-11 PET may non-invasively predict intraprostatic lesions in patients with PCa. [ABSTRACT FROM AUTHOR]

Natural photosynthetic protein complexes capture sunlight to power the energetic catalysis that supports life on Earth. Yet these natural protein structures carry an evolutionary legacy of complexity and fragility that encumbers protein reengineering efforts and obfuscates the underlying design rules for light-driven charge separation. De novo development of a simplified photosynthetic reaction center protein can clarify practical engineering principles needed to build new enzymes for efficient solar-to-fuel energy conversion. Here, we report the rational design, X-ray crystal structure, and electron transfer activity of a multi-cofactor protein that incorporates essential elements of photosynthetic reaction centers. This highly stable, modular artificial protein framework can be reconstituted in vitro with interchangeable redox centers for nanometer-scale photochemical charge separation. Transient absorption spectroscopy demonstrates Photosystem II-like tyrosine and metal cluster oxidation, and we measure charge separation lifetimes exceeding 100 ms, ideal for light-activated catalysis. This de novo-designed reaction center builds upon engineering guidelines established for charge separation in earlier synthetic photochemical triads and modified natural proteins, and it shows how synthetic biology may lead to a new generation of genetically encoded, light-powered catalysts for solar fuel production. De novo development of a simplified photosynthetic reaction center protein can clarify practical engineering principles needed to build enzymes for efficient energy conversion. Here, the authors develop an artificial photosynthetic reaction center that functions without the need for sacrificial electron donors or acceptors. [ABSTRACT FROM AUTHOR]

Upon impulsively loading a fully-clamped steel beam by firing a metallic foam projectile via a light-gas gun, a significant gap was experimentally observed between its transient peak deflection monitored during impacting and its permanent (residual) deflection measured after the impact was complete, i.e., springback had occurred. Finite element (FE) simulations were then performed to provide details concerning the evolution of stress and strain distributions as well as the initiation and traveling of plastic hinges in the beam, and the numerically calculated peak and residual deflections compared favorably with those measured experimentally. Subsequently, based upon the three distinct stages identified for the dynamically loaded beam, a beam-hinge analytical model was established to predict its springback response under sufficiently large uniform impulse, such that a portion of the beam or the entire beam was plastically yielded. The analytical predictions were compared with FE simulation results, with good agreement achieved. The validated model was then employed to systematically study the evolution of springback, the peak springback, the key factors affecting the magnitude of peak springback, and the roles played by different components constituting the internal energy stored in the beam. It was demonstrated that, as the impulsive load was increased, springback increased within the elasticity-dominated stage but decreased within the plasticity-dominated stage; the beam made of a metal having a higher yield strength exhibited a smaller peak deflection and a greater capacity to store elastic strain energy. Additional FE simulations revealed that strain hardening and strain rate effect led to further enhancement of springback. The present study clearly showed that springback is significant in dynamically loaded metallic structures, and hence should be accounted for in not only the design of practical protective structures but also their performance assessment. [ABSTRACT FROM AUTHOR]

The underbody of a vehicle system, either military or civil, is typically made of a relatively thin metallic plate, thus vulnerable to mine blast attacks. To improve the blast resistance, a multitude of protective structures have been proposed as attachments to the thin plate. In the present study, a novel ultralight all-metallic sandwich panel with three-dimensional (3D) tube cellular cores mounted to the vehicle underbody was envisioned as such a protective system. A metallic substrate (mimicking vehicle bottom) was placed above the proposed sandwich panel to construct a sandwich-substrate combinative structure. A series of sandwich panels having 3D tube cellular cores were fabricated via argon protected welding and laser welding. Mechanical responses of the combinative structure subjected to the denotation of 6 kg TNT explosives shallow-buried in dry sand were experimentally measured. Full numerical simulations with the method of finite elements (FE) were subsequently carried out to explore the physical mechanisms underlying the observed dynamic performance and quantify the effects of key geometrical parameters and connection conditions of the protective system. The performance of the proposed sandwich panel under shallow-buried explosives was also compared with competing sandwich constructions having equal mass. Finally, a preliminary optimal design of the 3D tube cellular core was carried out. [ABSTRACT FROM AUTHOR]

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the ongoing coronavirus disease 2019 pandemic. How SARS-CoV-2 regulates cellular responses to escape clearance by host cells is unknown. Autophagy is an intracellular lysosomal degradation pathway for the clearance of various cargoes, including viruses. Here, we systematically screened 28 viral proteins of SARS-CoV-2 and identified that ORF3a strongly inhibited autophagic flux by blocking the fusion of autophagosomes with lysosomes. ORF3a colocalized with lysosomes and interacted with VPS39, a component of the homotypic fusion and protein sorting (HOPS) complex. The ORF3a–VPS39 interaction prohibited the binding of HOPS with RAB7, which prevented the assembly of fusion machinery, leading to the accumulation of unfused autophagosomes. These results indicated the potential mechanism by which SARS-CoV-2 escapes degradation; that is, the virus interferes with autophagosome–lysosome fusion. Furthermore, our findings will facilitate strategies targeting autophagy for conferring potential protection against the spread of SARS-CoV-2. [ABSTRACT FROM AUTHOR]

Introduction: Over the last decades, multiple peptide receptors were recognized as potential diagnostic and therapeutic targets in nuclear medicine. 68Ga-NT-20.3 radiopharmaceutical has been developed for diagnosis of neurotensin receptors. High neurotensin receptor expression has been observed in pancreatic ductal adenocarcinoma as well as various malignancies. Until now, 68Ga-labelled NT ligand was successfully applied in in vitro as well as in animal model. Our study is the first in-human study on safety and tolerability of 68Ga-NT-20.3. Methods: Subjects were intravenously injected with 2.5 MBq of 68Ga-DOTA-NT-20.3 per kilogramme of body weight, and series of PET images were acquired at 5–25 min, 25–45 min, 45–65 min, and 65–85 min after 68Ga-NT-20.3 injection. Vital parameters are as follows: systolic and diastolic blood pressure (mmHg), heart rate (heart beat/min), respiratory rate (number of breaths/min), ECG, and body temperature (°C) were checked before, immediately after, and 3 h after 68Ga-NT-20.3 injection. The organ-absorbed doses were calculated for the self-dose and cross-dose from each organ region using the OLINDA/EXM version 2.1 software. Results and conclusion: The results from this small trial demonstrate that PET radiopharmaceutical 68Ga-NT-20.3 is safe and well tolerated. [ABSTRACT FROM AUTHOR]

We present an alternative concept for omnidirectional bending of light and concentration of energy in an index-continuous structure, comprising two gradient-index SiOx (0≤x≤2) layers and a thermochromic VO2 layer. The concept helps to overcome the constraints of conventional optics that are nonadjustable and only functional at designed wavelengths. The advantages of both gradient-index and thermochromic materials are combined in this work to realize temperature-tuned omnidirectional concentration of energy. Using a double-coated ICS component of AIR/SiOx/SUB/SiOx/VO2 for light manipulation and application near the visible spectrum range, this concept was numerically and experimentally demonstrated. The incoming light under oblique incident angles (0°–80°) was bent effectively and concentrated regardless of polarization. Favorable results demonstrated that a notably high energy concentration efficiency Pe (1.93–2.52) was achieved by varying the ambient temperatures (25–75 °C). This concept is general and can be applied in a variety of elements in light energy-efficient devices. [ABSTRACT FROM AUTHOR]

Spiking neural network (SNN) trained by spike-timing-dependent plasticity (STDP) is a promising computing paradigm for energy-efficient artificial intelligence systems. During the learning procedure of SNN trained by STDP, another two bio-inspired mechanisms of lateral inhibition and homeostasis are usually implemented to achieve competitive learning. However, the previous methods to implement lateral inhibition and homeostasis are not designed with hardware in mind, resulting in solutions that are not efficient for deployment on neuromorphic hardware. For example, the existing lateral inhibition methods induce a great number of connections that are proportional to the square of the number of learning neurons. The classical homeostasis methods depend on the fine-tuned membrane threshold with no hardware solution provided. In this paper, we propose two hardware-friendly and scalable methods to achieve lateral inhibition and homeostasis. Using only one inhibitory neuron for one learning layer, our proposed lateral inhibition method can reduce inhibitory connection number from N 2 to 2N and hardware overhead by sharing refractory control circuits. Utilizing the adaptive resistance of memristor, we propose a novel homeostasis method through adapting the leaky current of spiking neurons. In addition, the learning efficiency of different homeostasis methods are studied for the first time by simulating on the cognitive task of digital recognition of MNIST dataset. Simulation results show that our proposed homeostasis method can improve the learning efficiency by 30–50% while maintaining the state-of-the-art performance. [ABSTRACT FROM AUTHOR]

Recently, learning-based partial differential equation (L-PDE) has achieved success in few-shot learning area, while its feature weighting mechanism and recognition stability require further improvement. To address these issues, we propose a novel model called "location-dependent PDE" (LD-PDE) based on Navier–Stokes equation and rotational invariants in this paper. To our best knowledge, LD-PDE is the first application of the Navier–Stokes equation to achieve image recognition as a high-level vision task. Specifically, we formulate the feature variation with respect to each time step as a linear combination of rotational invariants in LD-PDE. Meanwhile, we design location-dependent mechanism to adaptively weight each invariant in an attention-based approach, which provides hierarchical discrimination in the spatial domain. Once the ultimate feature is learned, we measure the model error with the cross-entropy loss and update the parameters by the coordinate descent algorithm. As a verification, experimental results on face recognition datasets show that LD-PDE method outperforms the state-of-the-art approaches with few training samples. Moreover, compared to L-PDE, LD-PDE achieves a much more stable recognition with low sensitivity to its hyper-parameters. [ABSTRACT FROM AUTHOR]

Microalgae have been reported in many studies with high biomass, high carbohydrate content, fast growth rate and multiple bio-activities, while Dictyosphaerium sp. was rarely studied. Polysaccharide prove to be remarkable in many biological activities. To optimize the effects of the ultrasonic-assisted extraction parameters on the yield of polysaccharide from Dictyosphaerium sp., a single-factor experiment and response surface methodology (RSM) with a central composite rotatable design were employed. Four independent variables were investigated: X1 (ratio of raw microalgal powder to water), X2 (extraction temperature), X3 (extraction time), X4 (extraction power). The optimal conditions obtained via single-factor experiment were: X1 (1:25), X2 (50 °C), X3 (50 min), X4 (500 W), while according to the analysis of RSM, the optimum conditions were: X1 (1:26), X2 (58 °C), X3 (55 min), X4 (525 W). The refined polysaccharide were further prepared and characterized using SEM, FT-IR, XRD and TGA/DSC. Five kinds of antioxidant assays were carried out and the results indicated that the refined polysaccharide had strong scavenging ability to DPPH· and OH·. This study provides theoretical and experimental basis for the development and utilization of microalgal resources. [ABSTRACT FROM AUTHOR]

We present a THz emission enhancement of 41 times at 0.92 THz from a metasurface made of T-shaped resonators excited in a quasi-near-field zone. Such a metasurface has an intrinsic transmission minimum with Q factor of 4 at 1.25 THz under far-field excitation. When this metasurface is coupled onto the backside of a 625-μm-thick photoconductive emitter, the metasurface is below the Fraunhofer distance to the excitation source. As such, one broad enhancement around 0.47 THz and another extremely narrow enhancement at 0.92 THz in the emission spectrum are observed owing to a quasi-near-field excitation. Theoretically, the Q factor of the latter is up to 307, which is limited by the spectral resolution in experiment. The numerical simulations indicate that the T-shaped resonators serve as an array of plasmonic antennas resulting in the aforementioned emission enhancement of THz radiation. [ABSTRACT FROM AUTHOR]

Novel ultralight sandwich panels, which are comprised of corrugated channel cores and are faced with two identical solid sheets, subjected to generalized bending are optimally designed for minimum mass. A combined analytical and numerical (finite element) investigation is carried out. Relevant failure mechanisms such as face yielding, face buckling, core yielding and core buckling are identified, the load for each failure mode derived, and the corresponding failure mechanism maps constructed. The analytically predicted failure loads and failure modes are validated against direct finite element simulations, with good agreement achieved. The optimized corrugated channel core is compared with competing topologies for sandwich construction including corrugations, honeycombs and lattice trusses, and the superiority of the proposed structure is demonstrated. Corrugated- channel-core sandwich panels hold great potential for multifunctional applications, i.e., simultaneous load bearing and active cooling. [ABSTRACT FROM AUTHOR]

Nano-Ag sintering technology is a promising die attach method for power semiconductors in high reliability and high temperature (i.e. 300°C) applications. However, the present predictive models for thermal conductivity of multiphase materials are not suitable for the porous sintered Ag due to the model limitations of low porosity, i.e. < 10%, and simple pore geometry (sphere or ellipsoid). In this paper, an extension differential scheme (EDS) model based on the classical differential scheme (DS) approach has been developed. The thermal conductivity of the microporous Ag die attach layer on a SiC device was developed by measuring seven different sintering parameters that are fitted with the model. The finite element method (FEM) was also employed to analyze the influence of different factors. The results indicate that the EDS model has better adaptability and accuracy, which will be important for implementation of this new die attach material and technology. [ABSTRACT FROM AUTHOR]

Dual-level stress plateaus (i.e., relatively short peak stress plateaus, followed by prolonged crushing stress plateaus) in metallic hexagonal honeycombs subjected to out-of-plane impact loading are characterized using a combined numerical and analytical study, with the influence of the strain-rate sensitivity of the honeycomb parent material accounted for. The predictions are validated against existing experimental measurements, and good agreement is achieved. It is demonstrated that honeycombs exhibit dual-level stress plateaus when bucklewaves are initiated and propagate in cell walls, followed by buckling and progressive folding of the cell walls. The abrupt stress drop from peak to crushing plateau in the compressive stress versus strain curve can be explained in a way similar to the quasi-static buckling of a clamped plate. The duration of the peak stress plateau is more evident for strain-rate insensitive honeycombs. [ABSTRACT FROM AUTHOR]

To investigate the inclusion process of clove essential oil (CEO), saturated solution method was performed and β-cyclodextrin (β-CD) was used as wall materials. Based on the experimental results of single-factor experiments, response surface methodology (RSM) was employed to optimize the inclusion process. Ultraviolet spectrophotometry (US) was then used to verify the existence of inclusion complexes. Then, heat stability and antioxidant activities under different temperature were determined to estimate the inclusion process. 2,2′-diphenyl-1-picryhydrazyl (DPPH) scavenging capacity, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonicacid) (ABTS) scavenging capacity, anti-lipid peroxidation capacity and ferric reducing antioxidant power were used to determine the antioxidant capacities. The results showed that the optimum inclusion process of CEO was as follows: temperature, 43 °C, time, 2.5 h and ratio of β-CD to CEO, 9:1. Besides, inclusion process could strongly protect CEO from volatilization. This paper provided useful information to utilize the resource of Chinese herbal medicine and testified the great antioxidant activities of β-CD inclusion compound of CEO, and the optimized inclusion conditions of CEO from clove could be used in industrial production of health food. [ABSTRACT FROM AUTHOR]

Learning partial differential equations (LPDEs) from training data for particular tasks has been successfully applied to many image processing problems. In this paper, we propose a more effective LPDEs model for vector-valued image tasks. The PDEs are also formulated as a linear combination of fundamental differential invariants, but have several distinctions. First, we simplify the current LPDEs system by omitting a PDE which works as an indicate function in current ones. Second, instead of using L2-norm, we use the L1-norm to regularize the coefficients with respect to the fundamental differential invariants. Third, as the objective function is not smooth, we resort to the alternating direction method to optimize it. We illustrate the properties of our LPDEs system by several examples in denoising and demosaicking of RGB color images. The experiments demonstrate the advantage of the proposed method over other PDE-based methods. [ABSTRACT FROM AUTHOR]

In order to utilize the microalgal biomass sufficiently, thermogravimetry experimentation analyses of five microalgal strains (Chlorella sorokiniana C74 (C. sorokiniana C74), Desmodesmus sp. WC08, Chlorella sorokiniana XS04 (C. sorokiniana XS04), Scenedesmus ecornis G2 (S. ecornis G2) and Dictyosphaerium sp. 1A10) were performed by using TG–DTG–DSC (thermogravimetric–differential thermogravimetric–differential scanning calorimetry) thermal analysis technology. The combustion indexes, parameters and synthetic combustion characteristics were investigated. Meanwhile, the combustion kinetics parameters were identified with heating rates from 5 to 40 °C min−1 and conversion fractions from 0.1 to 0.9. The results showed that the burning TG–DTG curves of all five microalgal strains were different and the exothermic regions of five microalgal strains in DSC curves were different as well. The variation trends of apparent activation energy of Dictyosphaerium sp. 1A10, C. sorokiniana C74, C. sorokiniana XS04 and S. ecornis G2 differed from Desmodesmus sp. WC08. The average apparent activation energy of Desmodesmus sp. WC08 was highest followed by C. sorokiniana C74, Dictyosphaerium sp. 1A10, C. sorokiniana XS04 and S. ecornis G2. [ABSTRACT FROM AUTHOR]

Ultrasonic-assisted extraction (UAE) and microwave-assisted extraction (MAE) were developed to extract flavonoids antioxidants from the root of Millettia speciosa ( Millettia speciosa Champ.). The optimal experimental parameters for antioxidant extraction from M. speciosa Champ. were measured using single-factor experimentation combined with response surface methodology (RSM). Final extraction rate (FER) of flavonoids assay was used to quantify antioxidant compounds. Then, 2,2ˊ-diphenyl-1-picryhydrazyl (DPPH) scavenging capacity, 2,2ˊ-azino-bis(3-ethylbenzothiazoline-6-sulphonicacid) (ABTS) scavenging capacity and ferric reducing antioxidant power (FRAP) were used to determine the antioxidant capacities of extract. Besides, UAE and MAE were compared with conventional Soxhlet extraction (CSE) and M. speciosa Champ. powders were observed by scanning electronic microscopy to analyze the damage of cell structure caused by different extraction methods. The results showed that UAE was the optimal extraction method to extract flavonoids compounds from M. speciosa Champ. and the optimized UAE conditions of flavonoids was as follows: ethanol, 80%, temperature, 40 °C and ultrasonic power, 500 W. This paper provided useful information to utilize the resource of Chinese herbal medicine and manifest the great antioxidant activities of M. speciosa Champ., and the optimized UAE conditions of flavonoids from M. speciosa Champ. could be used in industrial production. [ABSTRACT FROM AUTHOR]

The interaction between terahertz (THz) resonance modes and element deformation in rectangular split-ring resonator (RSRR)-based meta-atoms (MAs) is investigated experimentally. Two types of RSRR-based MAs are presented: lateral-varied SRR (LV-SRR) and arm-twisted SRR (AT-SRR). When the distances from the gaps to the opposite sides of above meta-atoms increase from 10 to 40 μm, the inductive-capacitive (LC) resonance modes and dipole oscillation modes exhibit redshift behavior. The quality factor (Q factor) of LC resonance decreases while that of dipole oscillation modes increases. The THz mode interaction is subject to the distance between the gap and opposite side. An extension of lateral side contributes much more to the enhancement of Q factor of dipole oscillation mode than the twisted arms. The relationship between the near-field coupling effect and THz modes is revealed by the analysis of surface currents as well as the electric energy density distribution, as is in agreement with the experimental results. [ABSTRACT FROM AUTHOR]

Suppose a model has parameter $$\theta =(\psi , \lambda )$$ , where $$\psi $$ is the parameter of interest and $$\lambda $$ is a nuisance parameter. The integrated likelihood method eliminates $$\lambda $$ from the likelihood function $$L(\psi , \lambda )$$ by integrating with respect to a weight function $$\pi (\lambda | \psi )$$ . The resulting integrated likelihood function $$\bar{L}(\psi )$$ can be used for inference for $$\psi $$ . However, the analytical form for the integrated likelihood is not always available. This paper discusses 12 different approaches to computing the integrated likelihood. Some methods were originally developed for other computation purposes and they are modified to fit in the integrated likelihood framework. Methods considered include direct numerical integration methods such as Monte Carlo integration method, importance sampling, Laplace method; marginal likelihood computation methods; and methods for computing the marginal posterior density. Simulation studies and real data example are presented to evaluate and compare these methods empirically. [ABSTRACT FROM AUTHOR]

The toolpath for a sharp corner is important in pocket machining during high-speed machining with numerical control. When milling a sharp corner, a longer tool engagement length generates larger engagement angle and milling force, which reduces the machining precision. To reduce the milling force at a sharp corner and clear up uncut materials, the toolpath at corners must be optimized. In this paper, a new method of generating the toolpath with circular cycle transition at a sharp corner is put forward to provide a new numerically controlled toolpath pattern for pocket milling. On the basis of a common contour-parallel toolpath, minimum radius arcs and circular cycles are added in sequence at a sharp corner. When the cutter comes to the sharp corner, the corner material is removed step by step with a sequence of circular cycles. The validity of the proposed method is confirmed through simulation and tests. The proposed toolpath method is realized by employing the Institute of Manufacturing Technology (IMT) computer-aided manufacturing (CAM) system. The toolpaths at sharp corners generated through commercial software and IMT-CAM software are tested by comparing the corresponding milling forces. It is illustrated in the results that the proposed method reduces the milling force effectively and is of great significance when it is applied in high-speed machining. [ABSTRACT FROM AUTHOR]

The effects of trophic modes, carbon sources, and salinity on the growth and lipid accumulation of a marine oilgae Desmodesmus sp. WC08 in different trophic cultures were assayed by single factor experiment based on the blue-green algae medium (BG-11). The results implied that biomass and lipid accumulation culture process were optimized depending on the tophic modes, sorts, and concentration of carbon sources and salinity in the cultivation. There was no significant difference in growth or lipid accumulation with NaCO amendment or NaHCO amendment. However, NaCO amendment did enhance the biomass and lipid accumulation to some extent. The highest Desmodesmus sp. WC08 biomass and lipid accumulation was achieved in the growth medium with photoautotrophic cultivation, 0.08 g L NaCO amendment and 15 g L sea salt, respectively. [ABSTRACT FROM AUTHOR]

Introduction: This study aimed to evaluate the efficacy of local injection of bone mesenchymal stem cells (BMSCs) and fibrin glue in the treatment of atrophic nonunion in an animal model.Methods: Thirty-six male Lewis rats were randomly assigned into three groups: Group A (control group), Group B (atrophic nonunion group), and Group C (experimental group). All the rats underwent femoral osteotomy of the right hind limb, and stabilized with a custom-designed external fixator. Atrophic nonunion of the rats in Group B and C was induced by cauterization of the periosteum and bone marrow removal, and repaired by injection of fibrin glue and BMSCs-seeded fibrin glue, respectively. The surgically treated femurs were assessed by radiographic and histological analysis, and biomechanical test.Results: During the follow-up period, the external fixator maintained correct placement and all the femurs retained normal positioning. Eight weeks postoperatively, atrophic nonunion was detected in Group B, with the presence of fibrous connective tissue in the osteotomy gap. The femurs in Group C demonstrated complete bony bridging of the osteotomy gap, with the formation of plenty of woven bone.Conclusion: The repair of bone atrophic nonunion can be promoted through local injection of BMSCs and fibrin glue. [ABSTRACT FROM AUTHOR]

With its growth characteristic and chemoresistance, glioblastoma is the most deadly brain tumor. Twenty-five core genes that influence the chemosensitivity of glioblastoma were screened in our previous experiments, and Id2, the inhibitor of DNA binding 2, an oncogene encoding a helix-loop-helix protein, was identified. The elevated expression levels of Id2 have been reported in several malignancies. The aim of this study is to investigate the effects of Id2 expression on the chemosensitivity of glioma cells. In this study, Id2 expression was investigated in a malignant glioma cell line. Then, we silenced the expression of Id2 with the highly specific posttranscriptional suppression of RNA interference (RNAi) in U87 cells. The changes in response to antitumor agents Me-CCNU, VM26, and TMZ were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Apoptosis was measured using an annexin V-fluorescein isothiocyanate (FITC) apoptosis detection kit. The relationship between Id2 expression and caspase 3 was tested by RT-PCR and Western blot. This study demonstrated that Id2 was significantly upregulated in glioma tissues, and Id2 correlated well with the advancement of glioma grade and a worse prognosis in response to temozolomide treatment. The RNAi-mediated decrease of Id2 expression enhanced chemosensitivity to Me-CCNU, VM26, and TMZ in the U87 cell line. We further discovered that silencing of Id2 expression could promote apoptosis of glioblastoma cells, which could be attributed to the fact that Id2 affects tumor cell chemosensitivity. Downregulation of the Id2 gene by RNAi could increase the chemosensitivity of glioblastoma cells. Id2 could be a good molecular target for glioblastoma gene therapy. [ABSTRACT FROM AUTHOR]