This paper proposes a novel composite position controller for the field-oriented control (FOC) strategy of permanent-magnet synchronous motor (PMSM) servo systems. The proposed composite position ...controller integrates a position controller with a disturbance observer, with each designed based on a specific second-order sliding-mode algorithm. Specifically, the continuous twisting algorithm (CTA) is employed to develop the position controller for achieving rotor position tracking, while the modified super-twisting algorithm (STA) is used to construct the disturbance observer for compensating the total disturbance in the rotor position tracking error dynamics to enhance the dynamic performance. Comparative simulation tests, conducted within an FOC strategy of PMSM servo systems, contrast the performance of the CTA-based position controller, the composite position controller using a CTA-based position controller and a standard STA-based disturbance observer, and the proposed composite position controller. The simulation results validate the proposed position controller’s effectiveness and its superiority over comparable position controllers.
Antibiotic‐free methods hold particular promise for preventing and controlling multidrug‐resistant (MDR) bacterial infection via eradiation of bacteria and their pathogenic virulence. A facile and ...bioinspired strategy is presented for bridging antibacterial sonodynamic therapy and antivirulence immunotherapy. As a proof‐of‐concept, an antibody which neutralizes alpha‐toxin of methicillin‐resistant Staphylococcus aureus (MRSA) is genetically engineered on to the surface of cell membrane nanovesicles, which then undergo sonosensitizer encapsulation. Compared with conventional passive virulence absorption using natural red blood membrane, the highly active antibody–toxin interaction enables the nanovesicles to capture virulence more potently in vitro. Upon ultrasound activation, the sonosensitizers efficiently generate reactive oxygen species to kill bacteria and accelerate the virulence clearance. In vivo optical imaging shows that the antibody‐piloted nanocapturer can successfully locate MRSA infection and accurately distinguish the foci from sterile inflammation. In situ magnetic resonance imaging and oxyhemoglobin saturation detection visualize the treatment progression, revealing a complete sono‐immunotherapeutic eradication of MRSA myositis in mice. The first combination of antibacterial sonodynamic therapy and antivirulence immunotherapy, which promises a new way for antibiotic‐free nanotheranostics to robustly combat MDR bacterial infections, is presented.
A two‐birds‐with‐one‐stone nanocapturer is presented for bridging antibacterial sonodynamic therapy and antivirulence immunotherapy. A genetically engineered antibody on cell membrane nanovesicles (ANVs) potently reduces MRSA virulence. Upon ultrasound activation, sonosensitizers in the ANVs generate reactive oxygen species to kill bacteria and accelerate virulence clearance. Specific MRSA infection diagnosis is realized via fluorescence imaging and photoacoustic imaging.
Blue light photoreceptors, cryptochromes (CRYs), regulate multiple aspects of plant growth and development. However, our knowledge of CRYs is predominantly based on model plant Arabidopsis at early ...growth stage. In this study, we elucidated functions of CRY1a gene in mature tomato (Solanum lycopersicum) plants by using cry1a mutants and CRY1a‐overexpressing lines (OE‐CRY1a‐1 and OE‐CRY1a‐2). In comparison with wild‐type plants, cry1a mutants are relatively tall, accumulate low biomass, and bear more fruits, whereas OE‐CRY1a plants are short stature, and they not only flower lately but also bear less fruits. RNA‐seq, qRT‐PCR, and LC‐MS/MS analysis revealed that biosynthesis of gibberellin, cytokinin, and jasmonic acid was down‐regulated by CRY1a. Furthermore, DNA replication was drastically inhibited in leaves of OE‐CRY1a lines, but promoted in cry1a mutants with concomitant changes in the expression of cell cycle genes. However, CRY1a positively regulated levels of soluble sugars, phytofluene, phytoene, lycopene, and ß‐carotene in the fruits. The results indicate the important role of CRY1a in plant growth and have implications for molecular interventions of CRY1a aimed at improving agronomic traits.
The role of blue light signaling in plant growth and development remains unclear. Here, we report that CRY1a negatively regulates plant growth by inhibiting the biosynthesis of gibberellin and cytokinin, and the DNA replication, but positively regulates the accumulation of phytonutrients such as soluble sugars, phytofluene, phytoene, lycopene, and ß‐carotene in the fruits. Therefore, CRY1a–mediated blue light signaling is actively involved in the regulation of plant growth, development, and metabolism in tomato.
Lipid nanovesicles, including endogenous exosomes and synthetic lipid nanoparticles, have shown great potential in disease diagnostics, drug delivery, and cancer biology. Naturally secreted ...nanovesicles are promising biomarkers for early detection of cancers in vitro. Synthetic nanovesicles serve as robust drug delivery systems with enhanced tumor targeting in vivo. Microfluidic platforms with features of excellent flow control and rapid mixing are exploited as versatile tools for studying lipid nanovesicles of small sizes and delicate structures. Here, an overview of microfluidics for precise manipulation and synthesis of lipid nanovesicles is provided. The mechanisms of isolation and detection of exosomes in microfluidics, as well as the clinical utility of exosomes for cancer diagnosis, are discussed. Several microfluidic designs for controlled assembly of a variety of lipid nanovesicles are highlighted. Opportunities and outstanding challenges of microfluidics‐based investigation of lipid nanovesicles are discussed.
Lipid nanovesicles, including endogenous exosomes and synthetic lipid nanoparticles, have shown great potential in disease diagnostics, drug delivery, and cancer biology. An overview of recent advances of microfluidic methods for precise manipulation and synthesis of lipid nanovesicles is provided. A discussion on the clinical opportunities and challenges of lipid‐nanovesicles‐based cancer diagnostics and therapy by microfluidics is presented.
An artificial while very stable solid electrolyte interphase film is formed on lithium metal using an electrochemical strategy. When this protected Li anode is first used in a Li–O2 battery, the film ...formed on the anode can effectively suppress the parasitic reactions on the Li anode/electrolyte interface and significantly enhance the cycling stability of the Li–O2 battery.
Coronavirus disease 2019 (COVID-19), a highly infectious disease, has been rapidly spreading all over the world and remains a great threat to global public health. Patients diagnosed with severe or ...critical cases have a poor prognosis. Hence, it is crucial for us to identify potentially severe or critical cases early and give timely treatments for targeted patients. In the clinical practice of treating patients with COVID-19, we have observed that the neutrophil-to-lymphocyte ratio (NLR) of severe patients is higher than that in mild patients. We performed this systematic review and meta-analysis to evaluate the predictive values of NLR on disease severity and mortality in patients with COVID-19.
We searched PubMed, EMBASE, China National Knowledge Infrastructure (CNKI) and Wanfang databases to identify eligible studies (up to August 11, 2020). Two authors independently screened studies and extracted data. The methodological quality of the included studies was assessed by Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2).
Thirteen studies involving 1579 patients reported the predictive value of NLR on disease severity. The pooled sensitivity (SEN), specificity (SPE) and area under curve (AUC) were 0.78 (95% CI 0.70-0.84), 0.78 (95% CI 0.73-0.83) and 0.85 (95% CI 0.81-0.88), respectively. Ten studies involving 2967 patients reported the predictive value of NLR on mortality. The pooled SEN, SPE and AUC were 0.83 (95% CI 0.75-0.89), 0.83 (95% CI 0.74-0.89) and 0.90 (95% CI 0.87-0.92), respectively.
NLR has good predictive values on disease severity and mortality in patients with COVID-19 infection. Evaluating NLR can help clinicians identify potentially severe cases early, conduct early triage and initiate effective management in time, which may reduce the overall mortality of COVID-19.
This meta-analysis was prospectively registered on PROSPERO database (Registration number: CRD42020203612).
Exosomal microRNAs (miRNAs) are reliable and noninvasive biomarkers for the early diagnosis of cancer. Yet, accurate and feasible detection of exosomal miRNAs is often hampered by the low abundance ...of miRNAs in exosomes and the requirement for RNA extraction in large sample volumes. Here we show a thermophoretic sensor implemented with nanoflares for in situ detection of exosomal miRNAs, without resorting to either RNA extraction or target amplification. Thermophoretic accumulation of nanoflare-treated exosomes leads to an amplified fluorescence signal upon the binding of exosomal miRNAs to nanoflares, allowing for direct and quantitative measurement of exosomal miRNAs down to 0.36 fM in 0.5 μL serum samples. One of the best markers, exosomal miR-375, showed an accuracy of 85% for detection of estrogen receptor-positive breast cancer at early stages (stages I, II). This work provides a feasible tool to improve the diagnosis of cancer.
CO2 hydrogenation for the acquisition of value-added chemicals is an economical means to deal with the CO2-relevant environmental problems, among which CO2 reduction to CH4 is an excellent model ...reaction for investigating the initial steps of CO2 hydrogenation. For the supported catalysts commonly used in such reactions, the tailoring of the interfacial effect between metal centers and supporting materials so as to obtain superior low-temperature CO2 methanation performance is a significant but challenging subject. In this work, we altered the size regimes of the Ru deposits in Ru/CeO2 assemblies and uncovered the competitive relationship between the strong metal–support interactions (SMSI) and the H-spillover effect in determining the methanation activities by some ex situ and in situ spectroscopic techniques coupled with density functional theory (DFT) calculations. For CeO2 nanowire supported single Ru atoms, Ru nanoclusters (ca. 1.2 nm in size), and large Ru nanoparticles (ca. 4.0 nm in size), the nanoclusters show the most outstanding low-temperature CO2 methanation activity and 98–100% selectivity, with a turnover frequency (TOF) of 7.41 × 10–3 s–1 at 190 °C. The negative CO2 reaction order decreases their absolute values from single atoms to nanoclusters and turns positive in nanoparticles, while the positive H2 reaction order follows the reverse tendency. In situ DRIFTS measurements demonstrate that the dominant reaction pathway is the CO route, in which metal carbonyls are the critical intermediates and the active sites are those Ce3+–OH sites and Ru sites near the metal–support interfaces in charge of CO2 dissociation and carbonyl hydrogenation, respectively. Meanwhile, the strongest SMSI and H-spillover effect are respectively encountered in supported single Ru atoms and large Ru nanoparticles, with the activation of metal carbonyls and the dehydration of the support surfaces suppressed correspondingly. The two factors reach a balance in CeO2-supported Ru nanoclusters, and the methanation activity is therefore maximized. A mechanistic understanding of the interfacial effect in tuning the CO2 methanation activities would shed light on the ingenious design of the CO2 hydrogenation catalysts to utilize the SMSI and H-spillover effect to an appropriate degree and avoid their possible suppressions that would take place in extreme cases.
Ubiquitination of a subset of proteins by ubiquitin chain elongation factors (E4), represented by Ufd2p in Saccharomyces cerevisiae, is a pivotal regulator for many biological processes. However, the ...mechanism of Ufd2p-mediated ubiquitination is largely unclear. Here, we show that Ufd2p catalyses K48-linked multi-monoubiquitination on K29-linked ubiquitin chains assembled by the ubiquitin ligase (Ufd4p), resulting in branched ubiquitin chains. This reaction depends on the interaction of K29-linked ubiquitin chains with two N-terminal loops of Ufd2p. Only following the addition of K48-linked ubiquitin to substrates modified with K29-linked ubiquitin chains, can the substrates be escorted to the proteasome for degradation. We demonstrate that this ubiquitin chain linkage switching reaction is essential for ERAD, oleic acid and acid pH resistance in yeast. Thus, our results suggest that Ufd2p functions by switching ubiquitin chain linkages to allow the degradation of proteins modified with a ubiquitin linkage, which is normally not targeted to the proteasome.
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