Search

This paper investigates the problem of the functional interval observer design for linear time-varying (LTV) systems with additive disturbances in both input and output channels. First, sufficient conditions for the existence of a functional interval observer for LTV systems are proposed. Based on the solution of a type of Sylvester matrix equations (generalized Sylvester equations, GSEs), completely parameterized expressions of functional interval observer coefficient matrices are established, yielding a simple and effective design approach for solving the interval estimation issue of the LTV system, while the free parameters in the expressions provide the design degrees of freedom that can be utilized to achieve additional system specifications. Furthermore, the developed observer may execute state estimation at the desired convergence rate, considerably improving estimate performance. Finally, a numerical example and a back-to-turn (BTT) aircraft control example are presented, with the results showing that the upper and lower bounds provided by the designed observer provide a better performance of interval estimation of the functional state variables, demonstrating the effectiveness of the proposed method.

Background There is an unmet demand for non-invasive biomarker assays to identify patients benefiting from neoadjuvant immune checkpoint inhibitors (ICIs). Here, we aimed to characterize the composition and alterations in plasma metabolites and peripheral blood immune cell subtypes associated with neoadjuvant ICI efficacy in locally advanced esophageal cancer (LAEC) and to investigate potential novel therapeutic targets and non-invasive biomarkers for predicting ICI efficacy. Methods 89 patients with LAEC treated with neoadjuvant programmed cell death 1 blockade combined with chemotherapy were included in this study. We performed an untargeted metabolomic analysis of 606 metabolites on 72 plasma samples using high-performance liquid chromatography-mass spectrometry and an immune profiling analysis of 9 immune cell subtypes on 33 peripheral blood mononuclear-cell samples using flow cytometry. Furthermore, we conducted correlation network and pathway enrichment analyses for potentially beneficial and pathogenic metabolites to explore the metabolite-mediated ICI responses. Finally, a metabolite-based prediction model was established using the least absolute shrinkage and selection operator regression analysis. Results Comparative metabolomics revealed that pyrimidine and purine metabolic pathways were disturbed in ICI non-responders, with significant enrichment of dihydrothymidine, ureidoisobutyric acid, and deoxyadenosine, which were significantly associated with poor survival. Conversely, jasmonic acid increased dramatically in responders and was significantly associated with better survival. Strikingly, tryptophan metabolism intermediate-indole-3-acetic acid and arachidonic acid metabolism intermediate-16(R)-HETE levels were positively correlated with cytotoxic T lymphocyte levels but inversely correlated with polymorphonuclear-myeloid-derived suppressor cells levels, which were markedly associated with a favorable prognosis. Notably, the area under the receiver operating curve for the metabolite-based model predicting 12-month overall survival was 87.7% and 82.6% in the discovery and validation cohorts, respectively, demonstrating promising performance. Conclusions Our work identified potential non-invasive biomarkers based on plasma metabolic signatures for predicting neoadjuvant ICI responses and prognosis in patients with LAEC, which provides novel insight into ICI precision medicine in the management of LAEC.

In this study, a composite algaecide containing flocculants and Cinnamomum. camphora leaves extracts (CCCLE) were synthesized. The inhibition and flocculation effects on Microcystis aeruginosa (M. aeruginosa) were investigated, and the release of microcystin-LR (MC-LR) was determined. Results showed that the CCLEC composite algaecide was effective for the inhibition and flocculation of M. aeruginosa, and the optimal dose of CCLEC composite algaecide was 1.8%, which resulted in an algae inhibition ratio of 98.00% and a flocculation efficiency of 99.44% within 5 days of M. aeruginosa culturing. Besides, the total amount of MC-LR decreased by 80.04% on day 20 compared with the control group, while the concentration of intracellular MC-LR on day 5 was 36.69 μg L

Background This study aimed to estimate hepatitis B incidence and chronicity risk in rural adults in China under the background of eliminating viral hepatitis. Methods Hepatitis B surface antigen (HBsAg) screening was conducted every 2 years in demonstration areas since 2011. Individuals with baseline HBsAg-negative were included. Incidence was calculated as the number of HBsAg-positive cases divided by the total person-times. HBsAg-positive individuals were followed up to study the persistent infection (> 6 months), chronic infection (> 12 months), and recovery with hepatitis B surface antibody (anti-HBs). The chi-square test and cox proportional regression analysis were performed. Results There were 8,942 incident cases over 2,138,532 person-years, yielding an average incidence of 0.42 per 100 person-years. HBV incidence decreased rapidly in both genders and all age groups and then kept stable. Male gender, low population density, low gross domestic product per capita, and islanders were associated with higher incidence. Of the positive cases, 4,989 (55.8%) patients were followed up. The persistent infection, chronic infection, and recovery with anti-HBs rates were 32.3%, 31.0%, and 31.4%, respectively. Persistent or chronic infection was more common in younger adults and males, while seroconversion had no concern with gender or age. Conclusions HBV incidence in adult rural residents was decreasing and stayed low. The chronicity rate was relatively high and protective antibodies were induced in only one third. The importance of population-based screening and vaccination for susceptible individuals should be addressed.

Action detection is a challenging video understanding task, requiring modeling spatio-temporal and interaction relations. Current methods usually model actor-actor and actor-context relations separately, ignoring their complementarity and mutual support. To solve this problem, we propose a novel network called Multi-Relation Support Network (MRSN). In MRSN, Actor-Context Relation Encoder (ACRE) and Actor-Actor Relation Encoder (AARE) model the actor-context and actor-actor relation separately. Then Relation Support Encoder (RSE) computes the supports between the two relations and performs relation-level interactions. Finally, Relation Consensus Module (RCM) enhances two relations with the long-term relations from the Long-term Relation Bank (LRB) and yields a consensus. Our experiments demonstrate that modeling relations separately and performing relation-level interactions can achieve and outperformer state-of-the-art results on two challenging video datasets: AVA and UCF101-24., Comment: 6 pages

Additional file 1: Table S1. Members of committees and teams. Table S2. Investigators in the CAMI registry. Table S3. Baseline characteristics of patients with diabetes according fasting SHR levels. Table S4. Baseline characteristics of patients without diabetes according fasting SHR levels.

Based on CAFE theory and KGT model, the twin-roll strip casting mathematical model was established to solve the dendrite growth and solidification of T2 copper alloy in the molten pool. The influence mechanism of casting temperature, heat transfer, and other technological conditions on the microstructure of strip was analyzed. The results showed that the liquid metal formed 35 µm chilling layer after touching the rollers, and the layer was consisted of a high number of small and equiaxed crystals. Then some grains would appear close to the newly chilling layer, and grow toward the core of molten pool competitively. The dominant grains mainly grew along the 〈001〉 orientation into columnar crystals, and the rest grains that grew out of alignment were eliminated gradually. The number of grains declined, and the radius of columnar grains became coarsening. The Kiss point is a key factor for solidification structure, and the lower location of the Kiss point could limit the growth spaces of columnar crystals, which refined the grains.

Based on the three-dimensional field of molten pool and twin-roll strip casting experiments, this work verified the cracking mechanism of the strip by establishing mathematical model and rolling experiments. The results showed that due to the instability of the thermophysical field of the molten pool and the inconsistency of kiss curve height, the newly solidified strip will undergo incompatible deformation through the rolling. The stress concentration will appear around the large reduction area and then form slip bands. When plastic strain exceeds the limit of the metal, the oblique cracks will appear in the slip bands periodically or completely penetrate the strip. In addition, tensile cracks could also be produced by incompatible deformation. Therefore, keeping the uniformity and stability of the thermal physical field in molten pool is the key factor to restrain cracks.

Sox2 overlapping transcript (Sox2ot) is a long non-coding RNA (lncRNA), which harbors one of the major regulators of pluripotency, the Sox2 gene, in its intronic region. Sox2ot is primarily expressed in the developing neuroepithelium. However, its role in neural tube closure and embryonic development remains unclear. To investigate if Sox2ot is required for neural tube closure and embryonic development, Sox2ot promoter was deleted by CRISPR-Cas9 genome editing technology to prevent Sox2ot gene expression in mice. We designed 9 guide RNAs to specifically target the Sox2ot promoter and 3 gRNAs induced gene editing on the promoter of the Sox2ot gene in cells transfected with Cas9 mRNA and gRNAs. Then, these gRNAs and Cas9 mRNA were injected into mouse zygotes and implanted into pseudopregnant mice. A Sox2ot promoter-deleted mouse line was identified with complete deletion of promoter as well as deletion of exon 1 and exon 2. Sox2ot transcript was truncated with a lack of exon 1 and exon 2 in Sox2ot promoter-deleted mice. Furthermore, neural tube closure and embryonic development were checked at E9.5, E10.5, E14.5, E17.5 and after-birth (P2) and we did not find any failure of neural tube closure and aberrant embryonic development in Sox2ot promoter-deleted mice. Thus, our study demonstrated that CRISPR-Cas9 gene editing in Sox2ot promoter leads to its truncated expression and does not influence neural tube closure and embryonic development.

Red claw crayfish (Cherax quadricarinatus) is an economic freshwater shrimp with great commercial potential. However, the suitable stocking density of C. quadricarinatus is still unclear in integrated rice–crayfish farming system. Thus, this study aimed to investigate the effects of stocking density on growth performance, mitophagy, endocytosis and metabolism of C. quadricarinatus. The C. quadricarinatus was reared at low density (LD, 35.73 g/m2), middle density (MD, 71.46 g/m2) and high density (HD, 107.19 g/m2) in an integrated rice–crayfish farming system. After 90 days of farming, the growth performance of C. quadricarinatus significantly decreased in the MD and HD groups relative to that in the LD group. The HD treatment caused oxidative stress and lipid peroxidation at the end of the experiment in hepatopancreas. Transcriptome analysis showed that there were 1,531 DEGs (differently expressed genes) between the LD group and HD group, including 1,028 upregulated genes and 503 downregulated genes. KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis indicated that the DEGs were significantly enriched in endocytosis and mitophagy pathways. Meanwhile, four lipid metabolism pathways, including biosynthesis of unsaturated fatty acids, fatty acid biosynthesis, glycerolipid metabolism and glycerophospholipid metabolism, exhibited an upregulated tendency in the HD group. In conclusion, our data showed that when the stocking density reached up to 207.15 g/m2 in HD group, the growth performance of C. quadricarinatus was significantly inhibited in this system. Meanwhile, the data indicated that C. quadricarinatus may respond to the stressful condition via activating antioxidant defense system, endocytosis, mitophagy and metabolism-related pathways in hepatopancreas.

Red claw crayfish (

A Fourier transform spectrometer (FTS) has been used to observe solar activities due to its ultra-high spectral resolution. However, the FTS in-band spectra are usually distorted and some artifacts appear in out-of-band regions due to nonlinear effects. Therefore, the FTS nonlinear problem must be corrected. In this study, we proposed a novel method to correct the nonlinear effects using simulated annealing. We simulated several nonlinear spectra to evaluate the performance of our method. The calculated quadratic coefficients are extremely close to the given values, demonstrating that the method is effective and accurate. The proposed method is further used to correct the blackbody and solar spectra with nonlinearity obtained by Bruker IFS-125HR installed at the Huairou Solar Observing Station, which is a pathfinder for the accurate infrared magnetic field measurements of the Sun project. To the blackbody spectra, the nonlinearity in low- and high-frequency regions are corrected by 89.09% and 60.84%. The nonlinear correction of the solar spectra in the low- and high-frequency regions have reached 65.34% and 81.04%, respectively. These results prove that our method can correct the nonlinear problem to improve the data accuracy.

This study selects six consecutive 18.6 years of global M ≥ 7. 0 earthquakes, calculates the lunar declination angle based on the time of the earthquakes, and divides the global earthquakes into 13 research regions according to the global plate distribution facts to explore the lunar infl uence of earthquakes. The relationship between the lunar declination angle and these earthquakes is analyzed. The analysis results show that when the moon advances to a certain interval of its declination angle, the earthquakes are concentrated in a certain research region, whereas other research regions are relatively calm, providing a scientifi c basis for medium and long-term earthquake predictions in each research region. The 18. 6-year cycle is the lunar declination angle change cycle, and it is also the major nutation cycle of the earth’s motion and lunar node movement cycle. This is, in reality, the eff ect of the lunar node tide, which is worthy of further study.

Exploring the spatio-temporal dynamics of poverty is important for research on sustainable poverty reduction in China. Based on the perspective of development geography, this paper proposes a panel vector autoregressive (PVAR) model that combines the human development approach with the global indicator framework for Sustainable Development Goals (SDGs) to identify the poverty-causing and the poverty-reducing factors in China. The aim is to measure the multidimensional poverty index (MPI) of China’s provinces from 2007 to 2017, and use the exploratory spatio-temporal data analysis (ESTDA) method to reveal the characteristics of the spatio-temporal dynamics of multidimensional poverty. The results show the following: (1) The poverty-causing factors in China include the high social gross dependency ratio and crop-to-disaster ratio, and the poverty-reducing factors include the high per capita GDP, per capita social security expenditure, per capita public health expenditure, number of hospitals per 10,000 people, rate of participation in the new rural cooperative medical scheme, vegetation coverage, per capita education expenditure, number of universities, per capita research and development (R&D) expenditure, and funding per capita for cultural undertakings. (2) From 2007 to 2017, provincial income poverty (IP), health poverty (HP), cultural poverty (CP), and multidimensional poverty have been significantly reduced in China, and the overall national poverty has dropped by 5.67% annually. there is a differentiation in poverty along different dimensions in certain provinces. (3) During the study period, the local spatial pattern of multidimensional poverty between provinces showed strong spatial dynamics, and a trend of increase from the eastern to the central and western regions was noted. The MPI among provinces exhibited a strong spatial dependence over time to form a pattern of decrease from northwestern and northeastern China to the surrounding areas. (4) The spatio-temporal networks of multidimensional poverty in adjacent provinces were mainly negatively correlated, with only Shaanxi and Henan, Shaanxi and Ningxia, Qinghai and Gansu, Hubei and Anhui, Sichuan and Guizhou, and Hainan and Guangdong forming spatially strong cooperative poverty reduction relationships. These results have important reference value for the implementation of China’s poverty alleviation strategy.

Thallium (Tl) is a cumulative high toxicant in the environment, but few studies have investigated the comprehensive health effects underlying chronic Tl exposure at trace levels. This study aims to evaluate the liver, kidney, lung and other potential health effects associated with chronic Tl exposure at trace levels in rural areas of China. Urinary Tl concentrations of 2883 adults from rural areas of 12 provinces in China were measured and 2363 participants were involved in the final analysis. Indicators of liver and kidney functions in the serum, as well as the lung function indicators, were determined in the participants. General linear regression and restricted cubic spline regression were combined to study the associations between urinary Tl and health indicators or outcomes. In this study, the detected rate of Tl in the urine of the participants was 97.28 %. When the urinary Tl concentration was ranged at the fourth quintile, the risk of having liver function disorder was 70 % higher [Odds ratio (OR) = 1.70 (95 % confidence intervals (CI): 1.30, 2.22)] in all the participants, whereas the farmers were more likely to have the disorder [OR = 2.08 (95 % CI: 1.49, 2.92)] than the non-farmers [OR = 1.20 (95 % CI: 0.77, 1.88)]. Nonlinear associations between most of the liver health indicators and urinary Tl were identified, of which serum bilirubin was strongly associated with the elevation of urinary Tl when its concentration was0.40 μg/g creatinine. Besides, urinary Tl was negatively associated with lung health indicators. Our study proposes the safety re-assessment of the current exposure level of Tl in the environment, especially in rural areas of China.

In this paper, we present a parametric method to design proportional plus derivative (PD) state feedback for the problem of partial eigenstructure assignment (PESA) in a type of descriptor high-order linear time-invariant (LTI) systems. By dividing the original eigenstructure into replaced and remaining parts and using the solutions to the high-order generalized Sylvester equations (HGSEs), complete parameterized expressions of PD feedback controller and the replaced part of the right eigenvector matrix are established. With the proposed approach, the unsatisfactory eigenstructure in the open-loop system is changed into the expected eigenstructure in the closed-loop system, while the satisfactory part in the open-loop system is retained. Meanwhile, the regularity of the closed-loop system can also be well-guaranteed by the selection of arbitrary parameters. Finally, a numerical example and a flexible-joint robot system are presented to verify the feasibility and effectiveness of the proposed method, respectively.

This study investigates a parametric method to design a dynamic compensator for descriptor high-order quasi-linear (DHQ) systems. Utilising the solution to generalised high-order Sylvester equations, a more unified parametric form of the dynamic compensator is developed to improve the control effects. Meanwhile, normalisation design by using the dynamic compensator is also considered for DHQ systems such that the closed-loop regularity can be maintained easily and effectively. Whether the closed-loop form is singular or not, it has an expected eigenstructure. Finally, an example is provided to verify the parametric method is feasible and reliable.

This paper considers the parametric control to the Lorenz system by state feedback. Based on the solutions of the generalized Sylvester matrix equation (GSE), the unified explicit parametric expression of the state feedback gain matrix is proposed. The closed loop of the Lorenz system can be transformed into an arbitrary constant matrix with the desired eigenstructure (eigenvalues and eigenvectors). The freedom provided by the parametric control can be fully used to find a controller to satisfy the robustness criteria. A numerical simulation is developed to illustrate the effectiveness of the proposed approach.

Industrial transformation and high-quality urban development have become the core issues of urban-rural coordination and the leap forward in development in the new era. The research perspective of ‘pattern-process-mechanism’ is needed to reveal the spatiotemporal correlation characteristics of industrial transformation and urban economic efficiency evolution, and to expand its systematic, comprehensive and regional characteristics. Based on the geographical cognitive of local effects and spatial non-stationarity, we used a quantile regression model and a geographically weighted regression model to analyze the dynamic mechanism of industrial transformation and urban economic efficiency to explain the path characteristics of urban development and industrial transformation of the Yangtze River economic belt. The conclusions are as follows: (1) From 2000 to 2015, the average economic efficiency in the Yangtze River economic belt increased from 0.05 to 0.332, and the pattern gradually changed from spatial homogeneity to spatial mosaic; (2) From 2000 to 2015, the range and intensity of industrial transformation in the Yangtze River economic belt showed an increasing trend, while the speed of industrial transformation showed a downward trend, and the high-value unit of the three showed the characteristics of gradual homogenization; (3) From the perspective of the impact of industrial transformation on urban economic efficiency, the impact of the range and speed of industrial transformation on urban economic efficiency was gradually weakened, while the impact of the intensity of industrial transformation on urban economic efficiency was gradually strengthened, and the patterns of the three show the characteristics of a spatially inverted U-shaped distribution with high values in the middle reaches and low values in the upstream and downstream areas.

Temporal action detection (TAD) is extensively studied in the video understanding community by generally following the object detection pipeline in images. However, complex designs are not uncommon in TAD, such as two-stream feature extraction, multi-stage training, complex temporal modeling, and global context fusion. In this paper, we do not aim to introduce any novel technique for TAD. Instead, we study a simple, straightforward, yet must-known baseline given the current status of complex design and low detection efficiency in TAD. In our simple baseline (termed BasicTAD), we decompose the TAD pipeline into several essential components: data sampling, backbone design, neck construction, and detection head. We extensively investigate the existing techniques in each component for this baseline, and more importantly, perform end-to-end training over the entire pipeline thanks to the simplicity of design. As a result, this simple BasicTAD yields an astounding and real-time RGB-Only baseline very close to the state-of-the-art methods with two-stream inputs. In addition, we further improve the BasicTAD by preserving more temporal and spatial information in network representation (termed as PlusTAD). Empirical results demonstrate that our PlusTAD is very efficient and significantly outperforms the previous methods on the datasets of THUMOS14 and FineAction. Meanwhile, we also perform in-depth visualization and error analysis on our proposed method and try to provide more insights on the TAD problem. Our approach can serve as a strong baseline for future TAD research. The code and model will be released at https://github.com/MCG-NJU/BasicTAD., Comment: Accepted by CVIU

Additional file 1: Table S1. Coronary artery reference diameter of 231 age-sex-matched angiographically normal subjects.

Additional file 1: Table S1.Correlation analysis between NLR and inflammatory or glycemic indexes in patients with T2DM, without T2DM and whole. Table S2.. Univariable and multivariable Cox proportional hazard analysis for primary endpoint. Table S3NLR-associated MACCE risk according to different glycemic metabolism. Table S4.Predictive value of the NLR level in different glycemic status for MACCEs in univariable and multivariable analysis by using cut-off of 3.04. Table S5. Subgroup analysis for the primary endpoint as the unadjusted model. Table S6.Subgroup analysis for the primary endpoint as the adjusted model. Figure S1.Restricted cubic splines of NLR levels in relation to unadjusted HR(A) and adjusted HR(B) for the risk of MACCE.

Capturing the state changes of interacting objects is a key technology for understanding human-object interactions. This technical report describes our method using heterogeneous backbones for the Ego4D Object State Change Classification and PNR Temporal Localization Challenge. In the challenge, we used the heterogeneous video understanding backbones, namely CSN with 3D convolution as operator and VideoMAE with Transformer as operator. Our method achieves an accuracy of 0.796 on OSCC while achieving an absolute temporal localization error of 0.516 on PNR. These excellent results rank 1st on the leaderboard of Ego4D OSCC & PNR-TL Challenge 2022., 5 pages, 3 figures

In this work, the porous-carbon materials were successful synthesized via pre-oxidation and high-temperature carbonization treatment used the cotton fibers as raw materials. Activated carbon with h...

Intervertebral disc degeneration (IDD) is an important cause of lower back pain, although the underlying mechanisms remain poorly understood. The present study aimed to examine the role of a circular RNA derived from tissue inhibitor of metallopeptidases 2 (circ-TIMP2) in degenerative nucleus pulposus (NP) tissues, and to validate its function in cultured human NP cells. Overexpression of miR-185-5p in NP cells markedly inhibited the enhanced extracellular matrix (ECM) catabolism induced by tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) treatment. Bioinformatics analysis demonstrated that matrix metalloproteinase 2 (MMP2) was a potential target of miR-185-5p. MMP2 protein expression levels were increased following treatment with TNF-α and IL-1β in NP cells compared with those in untreated cells, and this effect was attenuated by transfection with miR-185-5p. Compared with normal NP tissues, IDD samples exhibited higher circ-TIMP2 expression levels. In addition, overexpres-sion of circ-TIMP2 promoted ECM catabolism and suppressed ECM anabolism. Furthermore, circ-TIMP2 sequestered miR-185-5p, which may potentially upregulate the target genes associated with ECM degradation. In conclusion, the results of the present study revealed that circ-TIMP2 promoted TNF-α- and IL-1β-induced NP cell imbalance between ECM anabolism and catabolism via miR-185-5p-MMP2 signaling. These findings provide a potential therapeutic option for the treatment of IDD.

The shapes of the urban lakes in Wuhan city have been strongly influenced by the rapid industrialization and urbanization experienced in recent decades. Based on topographic maps and remote sensing images, the temporal and spatial changes of East Lake, Wuhan city, over the past two decades were analyzed. The landscape shape index (LSI) and centroid method were applied to analyze the evolution of lake morphology and its causes. Several key results were obtained. (1) The surface area of East Lake decreased sharply by 2.13 km2 from 1995 to 2005, and slightly by 1.00 km2 from 2005 to 2015. The shoreline length of East Lake displayed a continuous trend of decline during the study period: The length reduced by 21.89 km from 1995 to 2005, and by 0.67 km from 2005 to 2015. The LSI values, 7.04 (1995), 6.46 (2005), and 6.28 (2015), displayed an accelerated downward trend, indicating a reduction of complexity in East Lake and the intensification of manual interventions in the water body. (2) The changes to East Lake displayed a clear temporal and spatial heterogeneity. The centroid of East Lake moved northeast from 1995 to 2005 and southeast from 2005 to 2015. (3) The reduction in the area of East Lake was mainly affected by human activities. A lake area of about 4.8 km2 was converted to other land uses during 1995–2005, most of which was unused land, whereas from 2005 to 2015, 0.43 km2 of the lake area was converted into built-up land, and 0.25 km2 was converted into other land uses. The reduction in area was caused by infrastructure construction by the government, the development of the real estate industry, illegal construction by villagers, and the development of scenic spots for tourism. The driving forces of this reduction included Wuhan’s growing population, and the rapid development of the economy and urbanization between 1995 and 2015, which has resulted in a large demand for land. Finally, a formation mechanism model was constructed by analyzing the causes of East Lake’s morphological evolution.

Catalysts applied for oxygen evolution reaction (OER) are vital to bring future renewable energy systems and convert the water to oxygen and hydrogen fuel. Herein, we report that bimetal-glycerate ...

The existing action recognition methods are mainly based on clip-level classifiers such as two-stream CNNs or 3D CNNs, which are trained from the randomly selected clips and applied to densely sampled clips during testing. However, this standard setting might be suboptimal for training classifiers and also requires huge computational overhead when deployed in practice. To address these issues, we propose a new framework for action recognition in videos, called {\em Dynamic Sampling Networks} (DSN), by designing a dynamic sampling module to improve the discriminative power of learned clip-level classifiers and as well increase the inference efficiency during testing. Specifically, DSN is composed of a sampling module and a classification module, whose objective is to learn a sampling policy to on-the-fly select which clips to keep and train a clip-level classifier to perform action recognition based on these selected clips, respectively. In particular, given an input video, we train an observation network in an associative reinforcement learning setting to maximize the rewards of the selected clips with a correct prediction. We perform extensive experiments to study different aspects of the DSN framework on four action recognition datasets: UCF101, HMDB51, THUMOS14, and ActivityNet v1.3. The experimental results demonstrate that DSN is able to greatly improve the inference efficiency by only using less than half of the clips, which can still obtain a slightly better or comparable recognition accuracy to the state-of-the-art approaches., Comment: To appear in IEEE Transaction on Image Processing

In this work, a dynamic self-optimizing material consisting of nickel–sulfide nanosheets anchored onto Ni foam (DSO-Ni3S2-NF) as the model material was constructed using a hydrothermal method, and its electrocatalytic performance for oxygen evolution was evaluated. It was found that the electrocatalytic activity of the dynamic self-optimizing (DSO) 25 h-Ni3S2-NF for oxygen evolution is significantly enhanced compared with that of pristine 0 h-Ni3S2-NF since the formed oxide layer evolves into new active sites and the specific process of activity optimization was explored dynamically. The best oxygen evolution reaction (OER) performance was achieved by 25 h-Ni3S2-NF catalyst, which required merely 241 mV overpotential to deliver a current density of 20 mA cm−2, and its Tafel slope was as low as ∼40 mV dec−1, which was superior to most nickel-based catalysts, in 1 M KOH electrolyte. The current density was found to be increased gradually at the same potential and the stability test curves were steady with ignorable decline, showing that the promising strategy of the preparation of a dynamic self-optimizing pre-catalyst may open a new pathway to prepare low-cost, high-performance and stable water splitting catalysts.

Modifying the surface active sites of Pt-based catalysts at the atomic level is of great significance to enhance the electrooxidation of methanol molecules. Herein, efficient active site assembly strategies are proposed, precisely, aimed at building high-performance electrocatalysts. Serving as proof-of-concept examples, both instances of Pt nanowires surface doping isolated Ru atoms (Ru/Pt NWs) and Ru nanoparticles supported on Pt nanowires (Ru@Pt NWs) are specially designed to optimize the catalytic performance of methanol oxidation reaction (MOR). The specific activity and mass activity of optimal Ru/Pt NWs can reach up to 3.93 mA cm-2 and 568.40 mA mg-1Pt, respectively, which is 1.53/1.94 times that of the Ru@Pt NWs and 2.03/2.59 times that of pure Pt NWs. Detailed studies on mechanism reveal that the Pt-Ru alloy can significantly improve the electron transfer kinetics of MOR, and activate more Pt atoms involved in the Langmuir-Hinshelwood (L-H) pathway compared with Ru@Pt NWs, all of which collectively accelerate the methanol oxidation. This surface engineering strategy via assembling active sites can reveal a promising method in the design of advanced Pt-based catalysts for direct methanol fuel cells.

To establish a model of reproductive system injury in male rats at high altitude using the low-pressure hypoxic animal laboratory and study the changes in the testicular tissue, semen parameters, blood gas and oxidative stress in male rats at different altitudes.Sixty male Wistar rats were randomly assigned to be raised on the plains (the plains group, n = 20), at an altitude of 4 000 m (the plateau model group Ⅰ, n = 20), or at an altitude of 6 000 m (the plateau model group Ⅱ, n = 20) for a spermatogenic cycle of 14 days. After establishment of the model of high-altitude reproductive system injury, the testis tissues of the rats were harvested for HE staining and observed for histopathological changes under the light microscope, and their epididymedes collected for preparation of sperm suspension and detection of sperm motility, sperm count and the percentage of morphologically abnormal sperm (MAS). The blood gas level and oxidative stress-related indexes in different groups were also measured using the serological test.With the elevation of altitude, the levels of pH and PO2 were decreased, those of PCO2, Hct, K+, Cl－ and Hb increased markedly, while that of Na+ exhibited no significant change. The model rats also showed folded spermatogenic tubule walls, thinned spermatogenic epithelia, disorderly arranged and reduced number of spermatogenic cells, and increased vascuolization in the spermatogenic epithelia, with decreased sperm motility and count, increased percentage of MAS, elevated concentration of malondialdehyde (MDA) and reduced activity of superoxide dismutase (SOD).A model of reproductive system injury was successfully established in male rats at a simulated altitude of 4 000 m. With increasing of the altitude to 6000 m, oxidative damage to the testicular tissue was aggravated, sperm motility decreased, and the percentage of MAS increased, indicating that an altitude of 6 000 m may cause serious damage to the rat reproductive system.

A plant’s early response to pathogen stress is a vital indicator of its disease resistance. In order to study the response mechanism of resistant and susceptible flax cultivars to Fusarium oxysporum f. sp. lini (Foln), we applied RNA-sequencing to analyze transcriptomes of flax with Foln 0.5, 2 and 8 hours post inoculation (hpi). We found a significant difference in the number of differential expression genes (DEGs) between resistant and susceptible flax clutivars. The number of DEGs in the Fusarium-resistant cultivar increased dramatically at 2 hpi, and a large number of DEGs participated in the Fusarium-susceptible cultivar response to Foln infection 0.5 hpi. GO enrichment analysis determined that the up-regulated DEGs of both flax cultivars were enriched such as oxidoreductase activity and oxidation-reduction process. At the same time, the genes involved in diterpenoid synthesis were up-regulated in resistant cultivar, while those involved in extracellular region, cell wall and organophosphate ester transport were down-regulated in susceptible cultivar. KEGG enrichment analysis showed the genes encoded WRKY 22 and WRKY33 which involved in MAPK signaling pathway were up-regulated expressed in S-29 and down-regulated expressed in R-7, negatively regulated the disease resistance of flax; The genes encoded Hsp 90 family which in involved in plant pathogen interaction pathway were up-regulated in R-7 and down-regulated in S-29, which positively regulated the disease resistance of flax; The genes encoded MYC2 transcription factor and TIFY proteins which involved in plant hormone signaling pathway were up-regulated in R-7, and regulated the jasmonic acid metabolism of flax and the signal transduction of plant hormones. Meanwhile seven regulatory genes with the most correlation were screened out, Among Lus10025000.g and Lus10026447.g regulated other genes expressed both in plant hormone signal transduction pathway and MAPK signal pathway. In conclusion, these findings will facilitate further studies on the function of these candidate genes in flax of response to Fusarium stress, and the breeding of disease-resistant flax cultivar.