This paper investigates the dynamic surface control of nonlinear transport aircraft model during the process of continuous heavy cargo airdrop in case of disturbance and actuator saturation. For the ...continuous airdrop process, the effects of moving process parameters include cargo mass and moving items upon the flight and the aircraft dynamics is with dramatic change. The dynamic surface related technique is designed for the attitude subsystem with unmatched disturbance and unknown dynamics so that in each step the virtual control is carefully considered using disturbance observer while the auxiliary signal is constructed in case of actuator saturation. The closed-loop stability is established via Lyapunov approach. In simulation test, it is interesting to find out that continuous airdrop process will deteriorate the system stability if additional control effort is not exerted. The proposed disturbance observer-based control can effectively enhance the reliability and robustness of the system, and can make sure of the smooth system performance at the instant of the heavy cargo separating from the aircraft.
Owing to the growing heat removal issue in modern electronic devices, electrically insulating polymer composites with high thermal conductivity have drawn much attention during the past decade. ...However, the conventional method to improve through‐plane thermal conductivity of these polymer composites usually yields an undesired value (below 3.0 Wm−1 K−1). Here, construction of a 3D phonon skeleton is reported composed of stacked boron nitride (BN) platelets reinforced with reduced graphene oxide (rGO) for epoxy composites by the combination of ice‐templated and infiltrating methods. At a low filler loading of 13.16 vol%, the resulting 3D BN‐rGO/epoxy composites exhibit an ultrahigh through‐plane thermal conductivity of 5.05 Wm−1 K−1 as the best thermal‐conduction performance reported so far for BN sheet‐based composites. Theoretical models qualitatively demonstrate that this enhancement results from the formation of phonon‐matching 3D BN‐rGO networks, leading to high rates of phonon transport. The strong potential application for thermal management has been demonstrated by the surface temperature variations of the composites with time during heating and cooling.
An oriented phonon‐matching skeleton is developed based on two kinds of 2D materials for efficient thermal conduction in polymer composites via ice‐templated assembly technology. This development leads to significantly improved through‐plane thermal conductivity for polymer composites when compared with traditional strategies, suggesting strong potential in thermal management. The results would benefit the design of novel thermal‐management materials.
Background
Serum prealbumin (PALB) can predict the prognosis of patients with gastric cancer (GC). However, the prognostic value of combination of C-reactive protein and PALB (CRP/PALB) remains ...unclear.
Methods
A total of 419 gastric cancer patients included in a clinical trial (NCT02327481) were analyzed. The present study is a substudy of the trial. Receiver operating characteristic (ROC) curves were generated, and by calculating the areas under the curve (AUC) and the C-index, the discriminative ability of each inflammatory index was compared, including CRP/PALB, C-reactive protein/albumin, Glasgow prognostic score (GPS), modified GPS, systemic immune-inflammation index, neutrophil–lymphocyte ratio, and platelet–lymphocyte ratio.
Results
Ultimately, 401 patients were included in this study. The optimal cutoff value of CRP/PALB was 17.7. According to this cutoff point, the entire sample was divided into a CRP/PALB < 17.7 (LCP) group and a CRP/PALB ≥ 17.7 (HCP) group, comprising 245 and 156 patients, respectively. There were 54 and 22 patients experienced recurrence in the HCP and LCP group, respectively,
p
< 0.001. Compared with traditional inflammatory indices, CRP/PALB had the highest AUC (0.707) and C-index (0.716), all
p
< 0.05. The post-recurrence survival (PRS) of patients in the HCP group was significantly shorter than that in the LCP group (
p
= 0.010), especially for pathological stage III patients (
p
= 0.015) or patients with distant (
p
= 0.018) or local (
p
= 0.023) recurrences.
Conclusions
The predictive value of preoperative CRP/PALB for the recurrence of GC is significantly better than traditional inflammatory indices. HCP significantly reduces the PRS, especially for pathological stage III patients or patients with distant or local recurrences.
In the face of high costs and the insufficient energy density of current lithium‐ion batteries, aqueous rechargeable zinc (Zn)–air batteries with the advantages of low cost, environmental benignity, ...safety, and high energy density have been growing in importance in recent years. The practical application of Zn–air batteries, however, is severely restricted by the high overpotential, which is associated with the inherent sluggish kinetics of the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) of air electrocatalysts. Recently, engineering heterostructured/hybrid electrocatalysts with modulated interface chemistry have been demonstrated as an effective strategy to improve the catalytic performance. Significant electronic effects, geometric effects, coordination effects, synergistic effects, and confinement effects occur at the heterostructure interface, which intensely affect electrocatalysts’ performance in terms of intrinsic activity, active site density, and durability. In this review, the recent progress in the development of heterostructured air electrocatalysts by interface engineering is summarized. Particularly, the potential relationship between interface chemistry and oxygen electrocatalysis kinetics is bridged and outlined. This review provides a comprehensive and in‐depth outline of the crucial role of the well‐defined interfaces towards fast oxygen electrocatalysis, and offers a solid scientific basis for the rational design of efficient heterostructured air electrocatalysts and beyond.
This review focuses on how interface engineering improves the intrinsic activity of catalysts and on enabling the stabilization of metal species when particle size is downsized to single atoms. The well‐established interface–kinetic relationship in this review highlights the unique attribute of interface and provides important insights into the mechanism of performance enhancement, establishing a scientific basis for the design of new heterostructured electrocatalysts.
Background. In the past decade, mesenchymal stem cells (MSCs) have been widely used for the treatment of osteoarthritis (OA), and noncoding RNAs in exosomes may play a major role. Aim. The present ...study is aimed at exploring the effect and mechanism of miR-326 in exosomes secreted by bone marrow mesenchymal stem cells (BMSCs) on pyroptosis of cartilage and OA improvement. Methods. Exosomes from BMSCs (BMSC-Exos) were isolated and identified to incubate with OA chondrocytes. Proliferation, migration, specific gene and miR-326 expression, and pyroptosis of chondrocytes were detected. BMSCs or chondrocytes were transfected with miR-326 mimics or inhibitors to investigate the effect of miR-326 in BMSC-Exos on pyroptosis of chondrocytes and the potential mechanism. Finally, a rat OA model was established to verify the effect and mechanism of miR-326 in BMSC-Exos on cartilage of pyroptosis. Results. Incubation with BMSC-Exos could significantly improve the survival rate, migration ability, and chondrocyte-specific genes (COL2A1, SOX9, Agg, and Prg4) and miR-326 expression of OA chondrocytes and significantly inhibit pyroptosis of chondrocytes by downregulation of the levels of inflammatory cytokines, Caspase-1 activity, and pyroptosis-related proteins such as GSDMD, NLRP3, ASC, IL-1β, and IL-18 (P<0.01). PKH26 labeling confirmed the uptake of BMSC-Exos by chondrocytes. Incubation with exosomes extracted from BMSCs overexpressing miR-326 can significantly repress the pyroptosis of chondrocytes, while knockdown of miR-326 had the opposite effect (P<0.01). The same result was also demonstrated by direct interference with the expression level of miR-326 in chondrocytes (P<0.01). In addition, we found that the overexpression of miR-326 significantly inhibited the expression of HDAC3 and NF-κB p65 and significantly promoted the expression of STAT1, acetylated STAT1, and acetylated NF-κB p65 in chondrocytes (P<0.01). The targeted relationship between miR-326 and HDAC3 was verified by dual-luciferase reporter assay. Animal experiments confirmed the mechanism by which miR-326 delivered by BMSC-Exos inhibits pyroptosis of cartilage by targeting HDAC3 and STAT1/NF-κB p65 signaling pathway. Conclusion. BMSC-Exos can deliver miR-326 to chondrocytes and cartilage and improve OA by targeting HDAC3 and STAT1//NF-κB p65 to inhibit pyroptosis of chondrocytes and cartilage. Our findings provide a new mechanism for BMSC-Exos to treat OA.
Pollution emissions have become a matter of public concern in recent years. However, the vast majority of existing researches on PM2.5 pollution are from the natural science perspective, and few ...studies have been conducted from an economic point of view. This paper adopts provincial panel data from 2001 to 2012 and panel data models to analyze the key driving forces of PM2.5 emissions at the regional level in China. The results show that economic growth is a decisive factor of PM2.5 emissions. The impacts of urbanization on PM2.5 emissions vary across regions and decrease continuously from the central region to the western and eastern regions. The effects of private cars and coal consumption on PM2.5 emissions in the eastern region are greater than that in the central and western regions because of significant differences in R&D investment, private car ownership and total coal consumption. Energy efficiency improvement has greater potential to mitigate PM2.5 emissions in the central and western regions than that in the eastern region due to its low level of technology. Hence, in order to effectively reduce emissions, the Chinese government should consider all these factors as well as regional heterogeneity in developing appropriate mitigation policies.
•We examine the key driving forces of PM2.5 emissions at the regional level in China.•The impacts of urbanization on PM2.5 emissions vary across regions.•Energy efficiency improvement has greater potential to mitigate PM2.5 emissions in the western region.•The regional difference should be taken into account in reducing China's PM2.5 emissions.
Massive open online courses (MOOCs) provide an opportunity for people to access free courses offered by top universities in the world and therefore attracted great attention and engagement from ...college teachers and students. However, with contrast to large scale enrollment, the completion rate of these courses is really low. One of the reasons for students to quit learning process is problems which they face that could not be solved by discussing them with classmates. In order to keep them staying in the course, thereby further improving the completion rate, we address the task of study partner recommendation for students based on both content information and social network information. By analyzing the content of messages posted by learners in course discussion forum, we investigated the learners’ behavior features to classify the learners into three groups. Then we proposed a topic model to measure learners’ course knowledge awareness. Finally, a social network was constructed based on their activities in the course forum, and the relationship in the network was then employed to recommend study partners for target learner combined with their behavior features and course knowledge awareness. The experiment results show that our method achieves better performance than recommending method only based on content information.
Abstract
Biomimetic mineralization can lead to advanced crystalline composites with common chemicals under ambient conditions. An exceptional example is biomimetic nacre with its superior fracture ...toughness. The synthesis of the prismatic layer with stiffness and wear resistance nonetheless remains an elusive goal. Herein, we apply a biomimetic mineralization method to grow prismatic-type CaCO
3
thin films, mimicking their biogenic counterparts found in mollusk shells with a three-step pathway: coating a polymer substrate, deposition of a granular transition layer, and mineralization of a prismatic overlayer. The synthetic prismatic overlayers exhibit structural similarity and comparable hardness and Young’s modulus to their biogenic counterparts. Furthermore, employment of a biomacromolecular soluble additive, silk fibroin, in fabrication of the prismatic thin films leads to micro-/nano-textures with enhanced toughness and emerging under-water superoleophobicity. This study highlights the crucial role of the granular transition layer in promoting competition growth of the prismatic layer.
Arthur classified the discrete automorphic representations of symplectic and orthogonal groups over a number field by that of the general linear groups. In this classification, those that are not ...from endoscopic lifting correspond to pairs
(
ϕ
,
b
)
, where
ϕ
is an irreducible unitary cuspidal automorphic representation of some general linear group and
b
is an integer. In this paper, we study the local components of these automorphic representations at a nonarchimedean place, and we give a complete description of them in terms of their Langlands parameters.
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