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This paper investigates the issue of determining the dimensions of row and column factor spaces in matrix-valued data. Exploiting the eigen-gap in the spectrum of sample second moment matrices of the data, we propose a family of randomised tests to check whether a one-way or two-way factor structure exists or not. Our tests do not require any arbitrary thresholding on the eigenvalues, and can be applied with no restrictions on the relative rate of divergence of the cross-sections to the sample sizes as they pass to infinity. Although tests are based on a randomization which does not vanish asymptotically, we propose a de-randomized, strong (based on the Law of the Iterated Logarithm) decision rule to choose in favor or against the presence of common factors. We use the proposed tests and decision rule in two ways. We further cast our individual tests in a sequential procedure whose output is an estimate of the number of common factors. Our tests are built on two variants of the sample second moment matrix of the data: one based on a row (or column) flattened version of the matrix-valued sequence, and one based on a projection-based method. Our simulations show that both procedures work well in large samples and, in small samples, the one based on the projection method delivers a superior performance compared to existing methods in virtually all cases considered.

In this paper, we study the discrepancy between the global principal component analysis (GPCA) and local principal component analysis (LPCA) in recovering the common components of a large-panel hig...

Modern multi-omic technologies can generate deep multi-scale profiles. However, differences in data modalities, multicollinearity of the data, and large numbers of irrelevant features make the analyses and integration of high-dimensional omic datasets challenging. Here, we present Significant Latent factor Interaction Discovery and Exploration (SLIDE), a first-in-class interpretable machine learning technique for identifying significant interacting latent factors underlying outcomes of interest from high-dimensional omic datasets. SLIDE makes no assumptions regarding data-generating mechanisms, comes with theoretical guarantees regarding identifiability of the latent factors/corresponding inference, outperforms/performs at least as well as state-of-the-art approaches in terms of prediction, and provides inference beyond prediction. Using SLIDE on scRNA-seq data from systemic sclerosis (SSc) patients, we first uncovered significant interacting latent factors underlying SSc pathogenesis. In addition to accurately predicting SSc severity and outperforming existing benchmarks, SLIDE uncovered significant factors that included well-elucidated altered transcriptomic states in myeloid cells and fibroblasts, an intriguing keratinocyte-centric signature validated by protein staining, and a novel mechanism involving altered HLA signaling in myeloid cells, that has support in genetic data. SLIDE also worked well on spatial transcriptomic data and was able to accurately identify significant interacting latent factors underlying immune cell partitioning by 3D location within lymph nodes. Finally, SLIDE leveraged paired scRNA-seq and TCR-seq data to elucidate latent factors underlying extents of clonal expansion of CD4 T cells in a nonobese diabetic model of T1D. The latent factors uncovered by SLIDE included well-known activation markers, inhibitory receptors and intracellular regulators of receptor signaling, but also honed in on several novel naïve and memory states that standard analyses missed. Overall, SLIDE is a versatile engine for biological discovery from modern multi-omic datasets.

Obstructive sleep apnea (OSA), characterized by chronic intermittent hypoxia (CIH), is a common risk factor for pulmonary arterial hypertension (PAH). As a hypoxia-induced transcription factor, differentially expressed in chondrocytes (DEC1) negatively regulates the transcription of peroxisome proliferative activated receptor-γ (PPARγ), a recognized protective factor of PAH. However, whether and how DEC1 is associated with PAH pathogenesis remains unclear. In the present study, we found that DEC1 was increased in lungs and pulmonary arterial smooth muscle cells (PASMCs) of rat models of OSA-associated PAH. Oxidative indicators and inflammatory cytokines were also elevated in the blood of the rats. Similarly, hypoxia-treated PASMCs displayed enhanced DEC1 expression and reduced PPARγ expression in vitro. Functionally, DEC1 overexpression exacerbated reactive oxygen species (ROS) production and the expression of pro-inflammatory cytokines (such as TNFα, IL-1β, IL-6, and MCP-1) in PASMCs. Conversely, shRNA knockdown of Dec1 increased PPARγ expression but attenuated hypoxia-induced oxidative stress and inflammatory responses in PASMCs. Additionally, DEC1 overexpression promoted PASMC proliferation, which was drastically attenuated by a PPARγ agonist rosiglitazone. Collectively, these results suggest that hypoxia-induced DEC1 inhibits PPARγ, and that this is a predominant mechanism underpinning oxidative stress and inflammatory responses in PASMCs during PAH. DEC1 could be used as a potential target to treat PAH.

Lithium metal batteries (LMBs) are highly considered as promising candidates for next-generation energy storage systems. However, routine electrolytes cannot tolerate the high potential at cathodes and low potential at anodes simultaneously, leading to severe interfacial reactions. Herein, a highly concentrated electrolyte (HCE) region trapped in porous carbon coating layer is adopted to form a stable and highly conductive solid electrolyte interphase (SEI) on Li metal surface. The protected Li metal anode can potentially match the high-voltage cathode in ester electrolytes. Synergistically, this ingenious design promises high-voltage-resistant interfaces at cathodes and stable SEI with abundance of inorganic components at anodes simultaneously in high-voltage LMBs. The feasibility of this interface-regulation strategy is demonstrated in Li | LiFePO4 batteries, realizing a lifespan twice as long as the routine cells, with a huge capacity retention enhancement from 46.4% to 88.7% after 100 cycles. This contribution proof-of-concepts the emerging principles on the formation and regulation of stable electrode/electrolyte interfaces in the cathode and anode simultaneously towards the next-generation high-energy–density batteries.

Lithium ion batteries have achieved extensive applications in portable electronics and recently in electronic vehicles since its commercialization in 1990s. The vast applications of lithium ion batteries are not only derived from the innovation in electrochemistry based on emerging energy materials and chemical engineering science, but also the technological advances in the powder technologies for electrode processing and cell fabrication. Revealing the effects of powder technology on electrode microstructure evolution during electrode processing is with critical value to realize the superior electrochemical performance. This review presents the progress in understanding the basic principles of the materials processing technologies for electrodes in lithium ion batteries. The impacts of slurry mixing and coating, electrode drying, and calendering on the electrode characteristics and electrochemical performance are comprehensively analyzed. Conclusion and outlook are drawn to shed fresh lights on the further development of efficient lithium ion batteries by advancing powder technologies and related advanced energy materials.

The accuracy of the CA-Markov model for landscape dynamic analysis is usually affected by environmental factors. In this study, the MCE-CA-Markov model with control conditions was used to predict the Baiyangdian basin landscape in 2023, based on landscape data for 2008, 2013, and 2018, and it was also compared with the simulation results of the CA-Markov model. The results showed that:From 2008 to 2018, the total area of farmland and forestland accounted for over 75% in Baiyangdian basin, which illustrated farmland and forestland were the substrate landscape. Landscape patches were fragmented and scattered, with the dominance of farmland and forestland gradually decreasing, and the diversity and complexity of the whole basin landscape pattern increased during this period. From 2018 to 2023, the farmland and forestland areas would decrease, while the area of other landscapes would increase. Landscape patches would mainly be compact and clustered, and dominance of construction land would gradually increase. The whole basin landscape pattern would tend to be diverse and even. The MCE-CA-Markov simulation accuracy(0.900 7) was higher than that of the CA-Markov simulation. Furthermore, the change range of the Baiyangdian basin landscape structure and pattern in 2023, simulated by the MCE-CA-Markov model, was smaller than that of the CA-Markov simulation, more congruent with social development in landscape transformation characteristics.

In this paper, an all-solid-state high voltage trigger generator is developed, which is aimed at triggering a several gigawatts three-electrode spark gap of an intense electron beam accelerator (IEBA). As one of the most important parts for triggering the IEBA precisely, it is developed based on a fractional-turn ratio saturable pulse transformer and a compact six-stage Marx generator. A pulse of rising time 141 ns and amplitude 79.6 kV is obtained on the 1000 Ω dummy load. The trigger is operated at pulsed repetition frequency over 10 Hz for testing its operational stability. The jitter counted from the initial control signal to the falling edge of the pulse is 0.64 ns. In addition, experiments of three-minute continuous repetitive operations at 10 Hz and higher frequency are carried out. The results show that the trigger generator has high stability even in long-time operations. So far, it successfully applies to the main switch of IEBA with a breakdown voltage of over 500 kV, and a total system jitter of 6.7 ns is acquired.

Hand, foot, and mouth disease (HFMD) has become one of the most common infectious diseases in China. Before 2016, the primary causal serotypes were enterovirus A71 (EV-A71) and coxsackievirus A16 (CV-A16). Following the introduction of EV-A71 vaccines in China since 2016, the situation could change. CV-A6 has recently replaced EV-A71 and CV-A16 in some areas of China. However, the epidemiological characteristics of central China remain unknown.To investigate the clinical symptoms and pathogen spectrum of HFMD in Shiyan City, central China, in recent years.The epidemiological, clinical, and laboratory data from HFMD cases reported to the Shiyan Center for Disease Control and Prevention between January 2016 and December 2020 were analyzed. 196 throat swab specimens were collected from hospitalized HFMD patients between January 2018 and December 2020. To detect and genotype enteroviruses, real-time reverse transcription-polymerase chain reaction and sequencing of the 5'-untranslated region were used. In Shiyan, 168 laboratory-confirmed HFMD cases were studied using a logistic regression model to determine the effect of predominant enterovirus serotypes. Based on the logistic regression model, the least absolute shrinkage and selection operator model was used to analyze the correlation between CV-A6 infection and various clinical characteristics in HFMD patients in Shiyan.From 2016 to 2020, 35840 HFMD cases were reported in Shiyan. The number of cases decreased by 48.4% from 2016 to 2017. Approximately 1.58-fold increases were found in 2018 and 2019 when compared to the previous year, respectively. In 2020, a decrease of about 85.5% was reported when compared to 2019. The most common serotypes shifted from EV-A71 and CV-A16 (about 60%-80% in 2016 and 2018) to others (more than 80.0% in 2017, 2019, and 2020). EV-A71 lost its dominance in 2017 in Shiyan. Among 196 confirmed HFMD cases, 85.7% tested positive for enterovirus, with CV-A6 being the most common serotype (121/168, 72.0%). The positive rates for CV-A16 and CV-A10 were 4.8% and 3.0%, respectively. There was no EV-A71 discovered. Infection with CV-A6 was linked to fever, myocardial damage, increased creatine kinase MB isoenzyme, and lactate dehydrogenase levels.CV-A6 was the most common enterovirus serotype in Shiyan City, replacing EV-A71 and CV-A16 as the HFMD pathogen. Developing vaccines against CV-A6 or multiple pathogens, as well as rising CV-A6 surveillance, will help prevent HFMD in central China.

In this study, the authors provide results of the precisely synchronized triggering of an intense electron beam accelerator (IEBA). The trigger generator was composed of a fractional-turn ratio saturable-pulse transformer and a compact six-stage Marx generator. The main switch of the IEBA was a corona-stabilized triggered switch (CSTS) based on the stabilized corona mechanism. The output voltage of a single IEBA exceeded 500 kV with less than 4 ns of jitter on a 50 Ω dummy load. We also conducted an experiment on the synchronous triggering of two IEBAs by using two independent trigger generators. The synchronization-related jitter was 6.1 ns, while the average time difference was 1.3 ns. We used this to attempt to trigger two parallel IEBAs by using a single trigger generator. The results showed a reduction in the synchronization-related jitter of 31% to 4.2 ns. The designs of the CSTS and the trigger generator guaranteed a precisely synchronous trigger by using a single trigger generator. Thus, the proposed method appears to be promising for accurately and synchronously triggering multiple IEBAs by using a single trigger generator. This provides an effective method to generate pulses with high power.

During continuous extrusion, the welds were formed at the confluence of two billets. Influences of extrusion wheel rotational speed on micromorphology and properties of welds of 6063 Al alloy were investigated through microstructure observation, tensile test, and SEM analyses. Welding parameters were analyzed using finite element simulation. Results indicated that metal welding was remarkably affected by oxide on outer surface of the double billets during continuous extrusion. Degree of oxide breakage on the welding surface increased due to the evident increase in effective strain rate with increasing extrusion speed. The high temperature induced by increased extrusion speed accelerated the formation of metallurgical bonding. A portion of weld seam lines slowly disappeared, and the proportion of the welding interface that failed to reach metallurgical bonding was also gradually reduced. Tensile strength and elongation of the weld specimen increased with the increase of extrusion speed.