Search

IntroductionGenetically edited pigs, modified using CRISPR-Cas9 technology, hold promise as potential sources for xenotransplantation. However, the optimal combination of genetic modifications and their expression levels for initial clinical trials remains unclear. This study investigates the generation of TKO/hCD55/hTM/hEPCR (6GE) pigs and evaluates their compatibility with human immune and coagulation systems.MethodsThe 6GE pigs were generated through iterative genome editing and F1 generation breeding. Genotyping, flow cytometry, and immunohistochemistry confirmed the knockout of GGTA1, CMAH, and B4GALNT2. Expression levels of human genes (hCD55, hTM, hEPCR) were quantified. In vitro assays using aortic endothelial cells (pAECs) from 6GE pigs assessed human serum IgM and IgG binding, complement cytotoxicity, and thrombin-antithrombin (TAT) complex levels. Blood from gene-edited pigs was used for pathophysiological analysis.ResultsComplete knockout of GGTA1, CMAH, and B4GALNT2 was confirmed in 6GE pigs. The expression of hCD55 and hTM was approximately seven and thirteen times higher than in humans, respectively, while hEPCR levels were comparable to those in humans. In vitro, 6GE pAECs showed significantly reduced binding of human IgM and IgG compared to wild-type pAECs (IgG p

T-NNPC inverter is an attractive topology with fewer switches and good withstand voltage for medium voltage applications. In order to effectively achieve five-level output, the conventional method is an MPC strategy that can quickly track current, ensuring good output performance under fundamental frequency conditions. However, the flying capacitor voltage fluctuates, especially under low-frequency conditions. In addition, the CO-PWM is a potential method for this topology due to the broader voltage level distribution in the vertical direction. Nevertheless, the flying capacitor voltage balancing cannot be guaranteed under the high modulation indexes. To improve voltage balance under various modulation indexes and current frequencies, this paper proposes an improved CO-PWM (ICO-PWM) method whose voltage level distribution is modified to better apply in the T-NNPC topology. Compared to the conventional MPC method, the flying capacitor voltage is more stable, and the fluctuation is reduced by more than five times, especially under low-frequency conditions. The effectiveness of the proposed ICO-PWM method is verified by the simulations and experiments.

The active neutral-point-clamped five-level converter has drawn much attention in industrial applications. However, common-mode voltage (CMV) suppression, accurate track current, fixed switching frequencies, neutral-point (NP) voltage balance, and flying capacitor (FC) voltage are compulsory in this configuration. Thus, an improved multiobjective model-predictive control (IMMPC) without weighting factors is proposed in this article. First, to suppress CMV, only 61 low-CMV vectors out of 125 vectors were selected. Second, to ensure current tracking performance and reduce computational burden, based on the gh oblique coordinate, three voltage vectors were calculated online in each control period, which can avoid lookup tables. Third, the optimal switching sequence and duty cycles were presented considering the lowest switching numbers and constant switching frequency. A high-quality current was thus obtained, and the NP voltage and the FC voltage were balanced by selecting switching combinations. The IMMPC can be applied to other multilevel converters for current tracking and CMV suppression with a simple adjustment on parameters. Finally, the feasibility and the effectiveness of the proposed method were verified through simulations and experiments.

Abstract Compared with a conventional three‐levelconverter, a reduced switch counts three‐level neutral point clamped (RSC‐3LNPC) inverter uses only 10 switching devices to achieve three‐leveloutput at a lower cost. However, in the RSC‐3LNPC inverter, the common modevoltage (CMV) reduction and neutral point voltage (NPV) balance are mutuallycoupled, and the buck switching module eliminates medium vectors, making conventional modulation methods no longer applicable. To address this problem, this paperdevelops a generation mechanism of the voltage and switching vectors for RSC‐3LNPC inverter and proposes a switching decomposition pulse width modulation (SDPWM) scheme. First, a virtual medium vector with two large vectors having the samedwell time is introduced. Then, the small and zero vectors with low CMV, along with the large and virtual medium vectors, are adopted, and by adjusting their dwell time, the NPV is balanced while reducing CMV. In addition, to reduce computational burden, the switching vector isdecomposed into a buck switching vector and a two‐level switching vector. Both switching vector sequences with transformed duty cycles are carefully designed to achieve only three switching transactions per switching period. Finally, validation and correctness of the proposed SDPWM scheme for RSC‐3LNPC inverterare verified by simulation and experiments.

Abstract Sepsis‐induced muscle atrophy often increases morbidity and mortality in intensive care unit (ICU) patients, yet neither therapeutic target nor optimal animal model is available for this disease. Here, by modifying the surgical strategy of cecal ligation and puncture (CLP), a novel sepsis pig model is created that for the first time recapitulates the whole course of sepsis in humans. With this model and sepsis patients, increased levels of the transcription factor zinc finger BED‐type containing 6 (ZBED6) in skeletal muscle are shown. Protection against sepsis‐induced muscle wasting in ZBED6‐deficient pigs is further demonstrated. Mechanistically, integrated analysis of RNA‐seq and ChIP‐seq reveals dedicator of cytokinesis 3 (DOCK3) as the direct target of ZBED6. In septic ZBED6‐deficient pigs, DOCK3 expression is increased in skeletal muscle and myocytes, activating the RAC1/PI3K/AKT pathway and protecting against sepsis‐induced muscle wasting. Conversely, opposite gene expression patterns and exacerbated muscle wasting are observed in septic ZBED6‐overexpressing myotubes. Notably, sepsis patients show increased ZBED6 expression along with reduced DOCK3 and downregulated RAC1/PI3K/AKT pathway. These findings suggest that ZBED6 is a potential therapeutic target for sepsis‐induced muscle atrophy, and the established sepsis pig model is a valuable tool for understanding sepsis pathogenesis and developing its therapeutics.

Organic ultraviolet absorbents (OUVAs) in the environment have been of increasing concern because of their potential hazards. However, the OUVAs in waters is far from being well studied and little is known about their occurrence in small urban rivers. This study investigated the concentrations and distribution of eleven OUVAs in the sediments from five small urban rivers of Tianjin, China, and found total concentrations in the range of 11.6–189 ng/g dry weight. Relative to other rivers and lakes, no high concentrations of sediment OUVAs were observed in the small rivers. Benzophenone, homosalate and octocrylene were the dominant OUVAs, representing medians of 13.3%, 12.4% and 12.3% of the total concentrations, respectively. Our observed composition profiles of these chemicals were different from those found in most of other waters. The sediment OUVAs may originate more from industrial activities than the use of cosmetics and personal care products in this area. The risk to aquatic organisms from exposure to the sediment OUVAs in these small urban rivers was considered low, except for benzophenone. However, more researches are needed to investigate the pollution and associated risks of these chemicals in urban rivers due to the complexity of their toxicity to aquatic organisms.

Genetic variants in the asialoglycoprotein receptor 1 (ASGR1) are associated with a reduced risk of cardiovascular disease (CVD) in humans. However, the underlying molecular mechanism remains elusive. Given the cardiovascular similarities between pigs and humans, we generated ASGR1-deficient pigs using the CRISPR/Cas9 system. These pigs show age-dependent low levels of non-HDL-C under standard diet. When received an atherogenic diet for 6 months, ASGR1-deficient pigs show lower levels of non-HDL-C and less atherosclerotic lesions than that of controls. Furthermore, by analysis of hepatic transcriptome and in vivo cholesterol metabolism, we show that ASGR1 deficiency reduces hepatic de novo cholesterol synthesis by downregulating 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), and increases cholesterol clearance by upregulating the hepatic low-density lipoprotein receptor (LDLR), which together contribute to the low levels of non-HDL-C. Despite the cardioprotective effect, we unexpectedly observed mild to moderate hepatic injury in ASGR1-deficient pigs, which has not been documented in humans with ASGR1 variants. Thus, targeting ASGR1 might be an effective strategy to reduce hypercholesterolemia and atherosclerosis, whereas further clinical evidence is required to assess its hepatic impact. Author summary Previous studies have reported an association between ASGR1 variants and CVD in humans. However, the underlying mechanism is unknown. We used ASGR1-deficient pig to recapitulate the reduced risk features of CVD in humans with ASGR1 variants, indicating that ASGR1 inhibition could be an effective strategy to treat atherosclerotic CVD. Our results highlight the demand for taking advantage of genetically modified large animal models to investigate the pathogenesis and therapeutic development of CVD in humans. Unexpectedly, we demonstrate the first link between ASGR1 deficiency and liver injury, a feature that has not been documented in humans with ASGR1 variants. These results suggest that ASGR1 might be an effective target for reducing CVD, whereas revealing a genetic predisposition to liver disease in humans with ASGR1 variants.

ZBED6 (zinc finger BED domain containing protein 6) is a transcription factor unique to placental mammals and its interaction with the IGF2 (insulin-like growth factor 2) locus plays a prominent role in the regulation of postnatal skeletal muscle growth. Here, we generated lean Bama miniature pigs by generating ZBED6-knockout (ZBED6-/-) and investigated the mechanism underlying ZBED6 in growth of muscle and internal organs of placental mammals. ZBED6-/- pigs show markedly higher lean mass, lean mass rate, larger muscle fiber area and heavier internal organs (heart and liver) than wild-type (WT) pigs. The striking phenotypic changes of ZBED6-/- pigs coincided with remarkable upregulation of IGF2 mRNA and protein expression across three tissues (gastrocnemius muscle, longissimus dorsi, heart). Despite a significant increase in liver weight, ZBED6-/- pigs show comparable levels of IGF2 expression to those of WT controls. A mechanistic study revealed that elevated methylation in the liver abrogates ZBED6 binding at the IGF2 locus, explaining the unaltered hepatic IGF2 expression in ZBED6-/- pigs. These results indicate that a ZBED6-IGF2-independent regulatory pathway exists in the liver. Transcriptome analysis and ChIP-PCR revealed new ZBED6 target genes other than IGF2, including cyclin dependent kinase inhibitor 1A (CDKN1A) and tsukushi, small leucine rich proteoglycan (TSKU), that regulates growth of muscle and liver, respectively.

The dual-input three-level inverter should have the ability to operate in certain areas where the dc-links are unbalanced. This paper proposes a generalized large-medium-zero space vector modulation (GLMZ-SVM) method to obtain high-quality output currents and suppress common-mode voltage (CMV) amplitude simultaneously when the dc-links are unbalanced. In this method, a modified space voltage vector diagram (MSVVD) based on the unbalancing factor is obtained, which is highly asymmetrical compared to the space vector diagram when the dc-links are balanced. Then, a novel sector division method of MSVVD is presented by six medium vectors and six large vectors. In each sector, the large, medium, and zero vectors are used to synthesize the reference voltage vector to reduce the CMV amplitude. The duty cycles of large, medium and zero vectors are calculated based on the modified volt-second balance principle with the unbalancing factor. To further reduce harmonics and avoid switching losses between switching cycles, a symmetrical five-segment switching sequence is designed. Comparisons with conventional methods show that the CMV amplitude of the proposed method is reduced by half and the high-quality output currents are obtained. Both simulation and experimental results validate the correctness of the theoretical analyses and the effectiveness of the proposed scheme.

Parallel photovoltaic inverters system can increase the power rating and efficiency. However, the zero-sequence circulating current (ZSCC) will be generated under unbalanced conditions. Therefore, this paper proposes a ZSCC control scheme for the M-paralleled (M ≥ 3) inverters under unbalanced grid voltage and unbalanced filter parameters. Based on the analysis with the proposed generalized model of parallel inverters, it is observed that the ZSCC of the ith inverter is influenced by the output currents, filter parameters, duty cycles and ZSCCs of the ith and first inverters. To eliminate these adverse effects on the ZSCC control loop, a decoupled controller consisting of modified input type PI-quasi-resonant and the feedforward controller is proposed. The modified input type PI-quasi-resonant controller mitigates the effects of the output currents, filter parameters, and ZSCCs, meanwhile, the feed-forward controller is employed to eliminate the difference of duty cycles. Compared with the conventional PI control method, the ZSCC is effectively suppressed with the proposed scheme, thus improving the quality of the currents. Moreover, the reliability of the paralleled system is improved because such scheme only needs the information of the ith and the first inverters. Simulation and experimental results obtained from three-paralleled inverters validate the effectiveness of theoretical analysis and the proposed method.

The asphalt binders could be modified to improve road perfo rmances by using various methods, and the reinforcement mechanisms are obviously different and quietly affect the road performances. According to the composite reinforcement theory, nano-CaCO3 particles, CaCO3 whiskers, and aramid fibers were used as reinforcements to prepare modified asphalt binders, and the conventional technical performances and dynamic shear rheometer (DSR) rheological properties were measured and investigated. In addition, scanning electron microscopy (SEM) was applied to observe the interfaces between reinforcements and asphalt matrixes and the different reinforcement mechanisms were analyzed. The test results showed that the use of nano-CaCO3 particles, CaCO3 whiskers, and aramid fibers can improve the high-temperature stability of modified asphalt binders by different reinforcement mechanisms. The nano-CaCO3 particles were still effective under high-temperature conditions and could last for a long time through the principle of dispersion enhancement. The CaCO3 whiskers segregate easily and cannot be well dispersed in asphalt binders. The aramid fibers played an important role of stress transmission and fiber reinforcement in asphalt binders, and 2 mm-aramid fibers hold the best reinforcement effects. The conclusions can provide a reference for the selection and application of modifiers in the preparation of modified asphalt in laboratory and engineering projects.