Search

Background The ongoing COVID-19 pandemic has caused global economic crisis and dramatic loss of human life. There is an urgent need for safe and efficient anti-coronavirus infection drugs. Anti-coronavirus peptides (ACovPs) can inhibit coronavirus infection. With high-efficiency, low-toxicity, and broad-spectrum inhibitory effects on coronaviruses, they are promising candidates to be developed into a new type of anti-coronavirus drug. Experiment is the traditional way of ACovPs identification, which is less efficient and more expensive. With the accumulation of experimental data on ACovPs, computational prediction provides a cheaper and faster way to find anti-coronavirus peptides candidates.Methods In this study, we integrated several state-of-the-art machine learning methodologies to build nine classification models for the prediction of ACovPs. These models were pretrained using deep neural networks, and the performance of our ensemble model, ACP-Dnnel, was evaluated across three datasets and independent dataset.Results The highest accuracy of ACP-Dnnel reaches 98%, and the MCC value exceeds 0.9. On three different datasets, its average accuracy is 96.33%. After the latest independent data set validation, ACP-Dnnel improved at MCC, Sn and ACC values by 10.1%, 16.4% and 7.3% respectively. It is suggested that ACP-Dnnel can be helpful for the laboratory identification of ACovPs, speeding up the anti-coronavirus peptide drug discovery and development. We constructed the web server of anti-coronavirus peptides prediction and it is available at http://150.158.148.228:5000/.

Exploiting high-performance, low-cost, and robust bifunctional catalysts toward electrochemical water splitting is of great importance, but remains challenging.

Both chronic obstructive pulmonary disease (COPD) and asthma are severe respiratory diseases. Bitter receptor–mediated bronchodilation is a potential therapy for asthma, but the mechanism underlying the agonistic relaxation of airway smooth muscle (ASM) is not well defined. By exploring the ASM relaxation mechanism of bitter substances, we observed that pretreatment with the bitter substances nearly abolished the methacholine (MCh)-induced increase in the ASM cell (ASMC) calcium concentration, thereby suppressing the calcium-induced contraction release. The ASM relaxation was significantly inhibited by simultaneous deletion of three Gα t proteins, suggesting an interaction between Tas2R and AChR signaling cascades in the relaxation process. Biochemically, the Gα t released by Tas2R activation complexes with AChR and blocks the Gα q cycling of AChR signal transduction. More importantly, a bitter substance, kudinoside A, not only attenuates airway constriction but also significantly inhibits pulmonary inflammation and tissue remodeling in COPD rats, indicating its modulation of additional Gα q -associated pathological processes. Thus, our results suggest that Tas2R activation may be an ideal strategy for halting multiple pathological processes of COPD.

Rational design of efficient, low-cost, and durable electrocatalysts for the hydrogen evolution reaction (HER) in various pH media is highly desirable but remains challenging. Herein, for the first time, we present a novel hybrid of ruthenium diphosphide encapsulated in P-doped porous carbon (denoted as RuP2@PC) utilizing metal–organic frameworks (MOFs) as templates by a multi-step strategy. Unexpectedly, benefitting from the synergistic contribution of highly dispersed ultrafine RuP2 nanoparticles, porous carbon skeleton, and P-dopant, the as-synthesized RuP2@PC exhibits exceptional catalytic activity and superior durability as pH-universal electrocatalysts for the HER. Particularly, a low overpotential of 78.9 mV to deliver a current density of 10 mA cm−2 and a small Tafel slope of 36.7 mV dec−1 can be achieved in 1.0 M KOH toward the HER. Such outstanding electrocatalytic properties exceed those of commercial Pt/C and rank the catalyst among the best HER electrocatalysts reported until now. Importantly, this work paves a new route in elaborately fabricating efficient and stable electrocatalysts based on MOFs for energy-related fields.

N,P-codoped porous carbon hollow nanosphere confining ultrafine molybdenum carbide nanoparticles are designed and prepared through a facile method. By virtue of the distinct composite and structure advantages, the resulting composite shows significantly enhanced electrocatalytic performance toward the hydrogen evolution reaction.

Both ferroelectric and switchable dielectric behaviors are of great academic value and practical significance, but they usually exist alone. If combine the two properties into one compound, it will be more valuable in practical application. In this paper, quasi-spherical (2-bromoethyl) trimethylammonium cation was used to match with [CdBr4 ]2- anion, and a new organic-inorganic hybrid compound ([BrCH2 CH2 N(CH3 )3 ]+2 [CdBr4 ]2- , BETABCdBr) was obtained and carefully characterized. The results indicate that this compound undergoes two continuous reversible phase transition around 342 K and 390 K. It could respectively exhibit ferroelectric and switchable dielectric properties over different temperature range. This work may provide a new clue to explore new types of bifunctional phase transition smart materials to meet various application requirements.

Ultrafine Ru nanoparticles dispersed on 3D N-doped carbon hollow nanospheres were firstly prepared by a feasible templating strategy. Due to the synergistic effect of the unique composite and structure, the resulting nanocomposite as a HER catalyst shows extraordinary electrocatalytic performance, superior to that of commercial Pt-C and most previously reported electrocatalysts.

Except for various properties, accurate and intuitive 3D representations of building elements and spaces are embedded in Building Information Models (BIMs). Thus, better understanding of spatial features of building elements and spaces is possible, which brings new opportunity in code compliance checking, indoor navigation, visualization, etc. With large amount of fine-grained 3D spatial data collected quickly and continuously, there is an urgent need for new methods to overcome problems like improper spatial expression, insufficient mining and utilization of information that exist in traditional methods. This research reviews state-of-the-art of related research and provides a summary of achievements and challenges in this area. Then, a framework consists of management, analysis, and application of 3D spatial data of BIM and a detailed discussion of each part are proposed, which would give the readers an overview of relevant methods, technologies, and tools. Moreover, potential research directions and open issues for future work are also discussed. The paper enables researchers to get a comprehensive understanding of 3D spatial data analytics of BIM as well as suggestions for future work, and thus makes a solid contribution in this area.

In this work, a high linearity AlGaN/GaN HEMT integrated dual threshold coupling (DT) technology and Schottky–Ohmic drain (SOD) were fabricated and analyzed. Since the architecture of DT synthesized planar- and recess-HEMT periodically along the gate width, SOD alleviated the peak electric field (E-field) around the gate region and the peak transconductance ( Gm-max) of 248 mS/mm with the associated transconductance plateau of ∼4.0 V at Vds = 28 V was obtained, which is evidently flatter than that of HEMT without the SOD structure. Attributed to the improved Gm linearity at high E-field, the DT-SOD HEMT exhibits the predicted linearity figure of merit of 5–13 dB when biased at class AB operation, which is ∼10 dB higher than that of DT-HEMT. Moreover, the fabricated device yields a nearly constant fT/ fmax of 47/118 GHz over a wide gate voltage, and load-pull measurements at 30 GHz reveal that these devices deliver output power density ( Pout) of 7.8 W/mm with the associated 1-dB compression point ( P1 dB) of 28.5 dBm at Vds = 28 V. The experimental results indicate that the employment of DT technology and SOD structure is an attractive approach to enhance the linearity at high E-field for millimeter wave devices.

The escalator intelligent design method with variable engineering parameters is proposed in this study by integrating the escalator parametric design and data-driven modeling method, in which, the developed intelligent design method provides efficient improvements in the solving the problems of escalator parametric intelligent layout and automatic modeling under different engineering conditions, for instance, different lifting heights and various station floor heights. Unlike other works in the literature, aiming to integrate the information collected by different equipment, the methods of Industry Foundation Classes (IFC) expansion and Dynamo parametric data acquisition platform is introduced to develop the BIM 4D model. The computational result in the case study and applications show that, a big data system for enabling visualization, monitoring, and warning of escalator operations is developed in this work, which can provide real-time monitoring and safety warning during the design, construction and operation stage of escalator operations.

Intractable functional constipation (IFC) is the most severe form of constipation, but its etiology has long been unknown. We hypothesized that IFC is caused by refractory infection by a pathogenic bacterium. Here, we isolated from patients with IFC a Shigella species - peristaltic contraction-inhibiting bacterium (PIB) - that significantly inhibited peristaltic contraction of the colon by production of docosapentenoic acid (DPA). PIB colonized mice for at least 6 months. Oral administration of PIB was sufficient to induce constipation, which was reversed by PIB-specific phages. A mutated PIB with reduced DPA was incapable of inhibiting colonic function and inducing constipation, suggesting that DPA produced by PIB was the key mediator of the genesis of constipation. PIBs were detected in stools of 56% (38 of 68) of the IFC patients, but not in those of non-IFC or healthy individuals (0 of 180). DPA levels in stools were elevated in 44.12% (30 of 68) of the IFC patients but none of the healthy volunteers (0 of 97). Our results suggest that Shigella sp. PIB may be the critical causative pathogen for IFC, and detection of fecal PIB plus DPA may be a reliable method for IFC diagnosis and classification.

N,P-codoped porous carbon hollow nanosphere confining ultrafine molybdenum carbide nanoparticles are designed and prepared through a facile method. By virtue of the distinct composite and structure advantages, the resulting composite shows significantly enhanced electrocatalytic performance toward the hydrogen evolution reaction.

Macrophages settle in heterogeneous microenvironments consisting of soluble or fixed biochemical components and biophysical clues rendered by other cells and extracellular matrices. It is well known that chemical stimuli direct macrophage behavior; however, the contributions of viscosity, which increase in inflammatory tissues but not in tumors, are ignored in related immune responses including effective activation and timely attenuation. This paper demonstrates that transient lipopolysaccharide (LPS)-treated macrophages benefit from elastic substrates, whereas viscoelastic substrates with similar storage moduli support the inflammatory responses of macrophages under persistent stimulations and consequently amplify the distinctions between the transient and persistent LPS-induced transcriptional programs. Actin filaments (F-actin), direct responders to mechanical stimulations, fluctuate in line with transcriptional profiles and can be mathematically predicted by a clutch-like model. Moreover, viscosity modifies immune responses through transcription factors NF-κB and C/EBPδ, which act as switches discriminating between the transient and persistent infections. Interestingly, enhanced immune responses, consistent with the lower activated states, are attenuated in a timely manner by the actin nucleation-related translocation of ATF3 to nuclei. These findings suggest that the substrate viscoelasticity induces more intense inflammation only in the case of persistent infection and serves as a key module for perceiving the duration of infection more sensitively through the F-actin correlated transcription factors. In addition, it may facilitate cognition of immune response in inflammatory and cancerous microenvironments and have a wide range of applications in inflammatory regulations. This article is protected by copyright. All rights reserved.

In this work, ultrathin barrier (∼6 nm) AlGaN/GaN high-electron-mobility transistors (HEMTs) with in situ SiN gate dielectric and slant-field plate (SFP) T-gates were fabricated and analyzed. Since the proposed scheme of gate dielectric and SFP effectively suppresses the gate leakage and alleviates the peak electric field (E-field) around gate region, the maximum breakdown voltage ( VBK) was improved to 92 V, which is 54 V higher than that of the conventional device. The fabricated ultrathin AlGaN/GaN HEMT with 60-nm SFP-T-gate exhibited the peak fT of 177 GHz and peak fmax of 393 GHz, yielding high figure-of-merits of fT · VBK = 16 THz V and fmax·VBK = 36 THz V. Moreover, load-pull measurements at 30 GHz reveal that these devices deliver output power density ( Pout) of 4.6 W/mm at Vds = 20 V and high power-added efficiency up to 52.5% at Vds = 10 V. Essentially, the experimental results indicate that the employment of SFP and in situ SiN gate dielectric is an attractive approach to balance the breakdown and speed for millimeter wave devices.

Both ferroelectric and switchable dielectric behaviors are of great academic value and practical significance, but they usually exist alone. If combine the two properties into one compound, it will be more valuable in practical application. In this paper, quasi-spherical (2-bromoethyl) trimethylammonium cation was used to match with [CdBr

The thymus is the central immune organ, but it is known to progressively degenerate with age. As thymus degeneration is paralleled by the wasting of aging skeletal muscle, we speculated that the thymus may play a role in muscle wasting. Here, using thymectomized mice, we show that the thymus is necessary for skeletal muscle regeneration, a process tightly associated with muscle aging. Compared to control mice, the thymectomized mice displayed comparable growth of muscle mass, but decreased muscle regeneration in response to injury, as evidenced by small and sparse regenerative myofibers along with inhibited expression of regeneration-associated genes myh3, myod, and myogenin. Using paired box 7 (Pax7)-immunofluorescence staining and 5-Bromo-2′-deoxyuridine-incorporation assay, we determined that the decreased regeneration capacity was caused by a limited satellite cell pool. Interestingly, the conditioned culture medium of isolated thymocytes had a potent capacity to directly stimulate satellite cell expansion in vitro. These expanded cells were enriched in subpopulations of quiescent satellite cells (Pax7highMyoDlowEdUpos) and activated satellite cells (Pax7highMyoDhighEdUpos), which were efficiently incorporated into the regenerative myofibers. We thus propose that the thymus plays an essential role in muscle regeneration by directly promoting satellite cell expansion and may function profoundly in the muscle aging process.

The microstructure of commercial pure copper TP2 tube by three roll planetary mill processing was investigated. Due to work hardening and subsequent softing by dynamic recrystallization during milling process,the coarse grain structure of the copper transformed to fine grain structure. The grain refinement is achieved along the axial moving in general; in the reducing zone, the sample has a gradient structure along the radial direction; uniform equiaxed grain with size of ~2 μm could be obtained at the outlet. The initiation of dynamic recrystallization occurred in the three roll planetary mill the reduction engineering strain reach ~30%, where some equiaxed grains replaced the elongated grains because of recrystallization.

A facile chemical precipitation approach is presented to fabricate flower-like zinc oxide (ZnO) nanorod clusters by using spherical cellulose nanocrystals (SCNs, with cellulose II crystal structure) as growth substrate. Field-emission scanning electron microscopy results showed that nanohybrids (A-100/11) with flower-like ZnO nanorod clusters could be formed under strongly alkaline (pH 11) conditions using suitable reaction time of 2 h and temperature of 100 °C, while rod-like nanohybrids could be obtained under weakly alkaline (pH 9.3 and 10.5) conditions or low temperature of 90 °C. A possible growth mechanism for flower-like ZnO on SCNs is discussed. Moreover, compared with commercial ZnO and rod-like nanohybrids, the flower-like A-100/11 nanohybrids showed better antibacterial activity against Streptococcus aureus and Escherichia coli, and excellent photocatalytic activity in presence of methylene blue as model dye.

Polarization imaging detection has its unique advantage in discriminating the man-made objects from natural objects. Grating integrated super pixel for polarization imaging detection can simultaneously obtain the first three elements of the Stokes vector, which is the trend of infrared polarization imaging detection in recent years. Here, we demonstrate the first super pixel for long wavelength infrared polarization imaging detection with the extinction ratio of its four polarization directions more than 100. The measured highest polarization extinction ratio is as high as 136, which is the highest reported value of long wavelength infrared polarization imaging detection super pixel. The mechanism is attributed to the excellent mode selectivity of plasmonic microcavity according to the results of three-dimensional theoretical simulation. The experimental responses of the super pixel with four polarization directions are in good agreement with the Malus’ Law. In addition, the super pixel can accurately resolve the Stokes parameters at the same time. It is expected to develop the super pixel into a new generation of practical high-polarization-discriminating long wavelength infrared focal plane array.

Cross-linked polyvinyl alcohol (PVA) composite films with high structural stability were prepared by free radical copolymerization between cellulose nanocrystal (CNC) and maleic anhydride (MAH) modified PVA through spraying Fenton free radical as initiator. The influence of chemical cross-linked and physical network structure on mechanical, thermal and water absorption properties of the composite films were investigated. Compared to PVA and PVA/CNC composite film, significant improvements in the mechanical, thermal and water uptake properties of the cross-linked composite film were found. The tensile strength of the cross-linked composite film was enhanced from 23.1MPa (neat PVA film) and 32.6MPa (PVA/CNC-10%) to 42.5MPa, and the maximum thermal degradation temperature was increased from 266.8°C and 281.2°C to 366.7°C (cross-linked composite film). Besides, the water absorption was reduced from 385.9% and 220.6% to 175.7% for cross-linked composite film. It indicates that compared with physical network structure in PVA/CNC composite film, the multiple cross-linked networks showed excellent thermal stability, resistance of water swelling and structural stability at the same CNC loading level. Thus, the PVA/CNC composite film with the multiple cross-linked network shows greater property reinforcements.

The relationship between the location of gate oxide breakdown in n-MOSFETs and its electrical characteristics has been studied by using TCAD software. The comparison of device terminal current with gate oxide breakdown at different locations suggests that the variation of the source and the drain currents can be directly correlated to the breakdown location in the ultra thin gate oxide. The results provide a fundamental understanding to the experimental results observed in our devices.