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This paper investigates the appointed‐time attitude stabilization problem of a rigid spacecraft under disturbance and parametric uncertainty. A continuous appointed‐time sliding mode disturbance observer is presented to observe the synthetical disturbance term. To circumvent the singularity problem in terminal sliding mode control, a new nonsingular appointed‐time sliding mode surface is designed by employing the concept of switching control. Based on the observation information deriving from the proposed disturbance observer, an observer‐based nonsingular sliding mode control scheme is developed to stabilize the attitude control system within appointed time which is given by the user. And also, the undesired control chattering phenomenon can be attenuated. The appointed‐time stability of the controlled attitude system is proved by the Lyapunov criteria. The simulation results show that the proposed attitude stabilization control scheme is valid. [ABSTRACT FROM AUTHOR]

The attitude tracking control problem of rigid spacecraft subjected to external disturbance and prescribed performance is studied. A fast fixed‐time stability theorem is firstly developed. A continuous disturbance observer is then designed with its estimation error can be driven into a tiny neighborhood containing zero within fixed time. Moreover, the spacecraft attitude tracking error constrained by prescribed performance function is transformed into an unconstrained dynamics. A disturbance observer‐based prescribed performance tracking controller is designed to stabilize the unconstrained dynamics within fixed time. It also means that the attitude tracking errors meet the prescribed performance as the stabilization of the unconstrained dynamics. Spacecraft simulation examples are finally given to validate the effectiveness of the proposed controller. [ABSTRACT FROM AUTHOR]

Objective: To investigate the occurrence rate of the prelacrimal recess (PLR) and its medial bony wall dimensions based on the radiological analysis to help surgeons enhance the understanding of anatomic structures for the endoscopic prelacrimal recess approach. Methods: Cone-beam computed tomography images of 255 patients were evaluated retrospectively. The prevalence of the PLR in maxillary sinus was investigated and the thickness of its medial bony wall was measured and statistically assessed. Meanwhile, the width of the PLR was measured. The correlation between the width of the PLR and its medial bony wall thickness was assessed. The data were compared between the left side and right side, male and female. Results: The PLR was present in 82.5% of the maxillary sinus, with no significant differences between the left and right sides, as well as different gender groups. The mean thickness of the medial bony wall of the PLR was 2.84 ± 1.41 mm, without statistical difference between the left and right sides but significantly larger in males than in females. The mean width of the PLR was 4.62 ± 1.74 mm and it had a significant negative correlation with the thickness of the medial bony wall of the PLR. Conclusion: A large individual variation exists in the anatomy of PLR, including its prevalence and dimensions of its medial bony wall. When considering the intranasal endoscopic prelacrimal recess approach, the surgeons should carefully evaluate the anatomical structure of the PLR preoperatively so as to minimize the risks of surgical complications. [ABSTRACT FROM AUTHOR]

Background: The intranasal endoscopic prelacrimal recess approach (PLRA) to the maxillary sinus (MS) has been reported to treat many MS and skull base diseases. However, previous studies revealed that the width of the prelacrimal recess (PLR) shows a large individual variation. The purpose of this study was to ascertain the prevalence of the PLR in MS according to gender and age. Methods: A series of 701 maxillofacial cone beam computed tomography (CBCT) scans from adult patients were analyzed retrospectively. Patients were divided into five age groups (18–24 years, 25–34 years, 35–44 years, 45–54 years, and ≥ 55 years) and by sex. The frequencies of occurrence of the PLR in the MS were calculated and compared. Results: According to the findings obtained from our study, PLR was present in 81.5% of maxillary sinuses. No differences were found when the data distributions of right and left sides were compared. For individuals, the right and left sides were not always symmetrical. The probability of PLR was lesser among women than among men, but this differences was not significant. Another finding of our study was that the percentage of PLR decreased with increasing age among patients aged < 55 years, however, increased again among patients aged ≥ 55 years. Conclusion: The anatomy of PLR varies among individuals. Careful analysis of individual anatomical structure characteristic is recommended when considering intranasal endoscopic PLRA to the MS. Besides, the age variation of PLR should be considered in order to avoid complications. [ABSTRACT FROM AUTHOR]

• Li-Mg alloy/Li 3 PO 4 alloy/ion conductor composite as Li metal anode is proposed. • Li-LMP anode shows a better Li+ transference ability than Li foil's one. • The inner deposit/strip of Li occurs in the Li-LMP anode during operation. • The ion conductivity of Li-LMP is offered by Li 3 PO 4 and Li-Mg/Li 3 PO 4 interface. • Li-LMP shows good cycle and rate performance in symmetric cell and full cell. With the increasing energy density demand for lithium-ion batteries, Li metal anode catches much attention owing to its ultrahigh theoretical capacity and low electrochemical potential. However, lithium is highly reactive and easily forms dendrites and fractures during deposition, which leads to low coulombic efficiency and severe safety problem. Thereby, suppressing the growth of Li dendrites to stabilize the Li/electrolyte interface is vital to lithium metal anode. Here, we introduce a strategy to construct a Li alloy/ion-conductor composite anode via a one-step conversion-alloying reaction. The pristine LiMgPO 4 are converted to ion-conductive Li 3 PO 4 and Mg, and Mg reacts with Li to form Li-Mg alloy, resulting in a final Li-LMP composite. The alloying and the generation of nanosized Li 3 PO 4 not only enhance the mechanical strength of Li-LMP, making it more durable to the local stress during cycling, but also enhance ion transfer inside Li-LMP, showing a faster kinetic mass transfer process. As a consequence, Li-LMP shows promoted rate performance (LFP || Li-LMP could deliver 72 mAh g−1 at 10C) and cycle stability both in ether and carbonate electrolytes. [ABSTRACT FROM AUTHOR]

Laryngeal squamous cell carcinoma (LSCC) with a high incidence and mortality rate, has a serious impact worldwide. Phosphofructokinase-1 liver type (PFKL) is a major enzyme in glycolysis progress, but its role in modulating tumorigenesis and cisplatin (DDP) chemosensitivity of LSCC was still unclear. The mRNA and protein levels of PFKL were detected by qRT-PCR and immunohistochemical assay. Cell Counting Kit-8 assay and flow cytometry were carried out to observe cell viability, as well as apoptosis and mitochondrial reactive oxygen species (mito-ROS). Extracellular acidification rate and lactate content were measured using extracellular flux analysis and lactate assay kit. Immunofluorescent staining was used to evaluate the expression of γ-H2AX foci. DNA damage was detected via single-cell gel electrophoresis. Western blotting was introduced to evaluate the protein level of PFKL, LDHA, γ-H2AX, cleaved PARP, H3K27ac, and H3K9ac. Mice xenograft model of LSCC was built for in vivo validation. The PFKL expression was significantly increased in LSCC and associated with poor survival of LSCC patients. Knockdown of PFKL in LSCC cells significantly inhibited cell viability, ECAR, lactate content, and LDHA expression, but promoted mito-ROS level. Furthermore, knockdown of PFKL enhanced response of LSCC cells to DDP by increasing DDP-induced apoptosis, promoting DDP-induced mito-ROS level, γ-H2AX foci, tail DNA, and the expression of γ-H2AX and cleaved PARP. However, the overexpression of PFKL in LSCC cells had opposite experimental results. Nude mice tumor formation experiment proved that downregulation of PFKL significantly enhanced response of cells to DDP, demonstrated by reduced tumor volume, weight and increased TUNEL-positive cells. Suppression of CBP/EP300-mediated PFKL transcription inhibited cell viability and glycolysis and promoted mito-ROS in LSCC. PFKL promotes cell viability and DNA damage repair in DDP-treated LSCC through regulation of glycolysis pathway. • PFKL is elevated in patients with LSCC and associated with poor survival. • PFKL knockdown promotes mito-ROS and inhibits glycolysis in LSCC. • PFKL regulates DDP chemosensitivity of LSCC in vitro and in vivo. • PFKL regulates DNA damage repair in DDP-treated LSCC cells. • CBP/EP300-mediated PFKL transcription contribute to LSCC progression. [ABSTRACT FROM AUTHOR]

Glass fibre reinforced polymer (GFRP) pipelines are widely used in civil and offshore engineering owing to their good mechanical performance and light weight. However, typical structural problems, such as low radial stiffness, are still existing in the GFRP pipelines. In this paper, a novel GFRP sandwiched pipeline structure with a stiffened core was designed and was integrally fabricated by a newly developed multistage filament winding (MFW) technique. The radial stiffness of the GFRP stiffened pipe was investigated through a combination of theoretical, numerical and experimental methods. It was found the structural layer formed by GFRP webs combined with foam blocks effectively increase the stiffness with a considerable weight reduction for the newly proposed pipe structure. In addition, the mechanical behaviour of the stiffened pipe was precisely predicted by the adopted theoretical method and the proposed numerical model. Based on the validated model, the structural stability under confined load of the GFRP stiffened pipe was numerically studied and the failure map was constructed as a function of the related geometric parameters. The results provided a new concept for the pipeline structural design and a guidance for the geometric optimization of the proposed pipeline configuration. • A novel GFRP sandwiched pipe with stiffened core was designed to achieve the light-weight pipeline design. • An integrated fabrication technique, namely multi-stage winding, was developed to manufacture the stiffened pipe. • The stiffened pipe achieved a full use of structural layers, featured by a composite failure rather than a delamination. • The stiffened pipe achieved around 67% weight reduction comparing to the mortar pipe at the same stiffness level. [ABSTRACT FROM AUTHOR]

• Blast tests were conducted to study the combined loading effects and failure characteristics of two-way RC slabs. • Numerical simulation based on FEM-SPH (finite elements-smoothed particle hydrodynamics) method is in good agreement with experiments. • The effect of the standoff distances on the damage of the RC slabs is discussed, and analytical expressions are derived. This paper aims at investigation of failure characteristic of RC slabs under combined blast and fragment loading. With experimental device designed, blast tests were conducted to study the combined loading effects and failure characteristics of two-way RC slabs. Numerical studies based on FEM-SPH (finite elements-smoothed particle hydrodynamics) method were carried out and good agreement was obtained between numerical simulation and the testing results. The validated numerical model is then used to carry out parametric studies on damage classification. It is demonstrated that there was spall damage, penetration, crack and fragment in concrete slabs under combined loading. Besides, both explosive mass and standoff distance have profound effects on RC slab damage. [ABSTRACT FROM AUTHOR]

Along with the living environment, organisms have evolved structures that adapt to specific environments and have better mechanical properties. Bioinspired materials learn from nature and improve their mechanical properties by imitating the structure of living organisms. Based on the 4D printed shape memory polymer and the bioinspired design method, this research proposes a soft and hard phase hybrid bioinspired metamaterial with shape memory effect and programmable mechanical properties. Compared with traditional nacre-like materials, bioinspired materials have adjustable characteristics of mechanical properties, impact resistance, and low-frequency vibration isolation. First, based on the constitutive relation of SMP (Shape memory polymer) material and its numerical simulation, an intelligent bioinspired metamaterial is designed. Subsequently, the mechanical properties and vibration isolation behavior and adjustability performance of multi-scale bioinspired metamaterials are explained by experiments. Finally, the adjustable functional mechanism of the deformation and vibration isolation of the bioinspired metamaterial is described. The research of these bioinspired metamaterials has broad application prospects in the fields of impact protection and low-frequency vibration absorption. [ABSTRACT FROM AUTHOR]

Over the last century, our societies have experienced a sharp increase in urban population and fossil-fuelled transportation, turning air pollution into a critical issue. It is therefore key to accurately characterize the spatiotemporal variability of surface air pollution in order to understand its effects upon the environment, knowledge that can then be used to design effective pollution reduction policies. Global atmospheric composition reanalyses offer great capabilities towards this characterization through assimilation of satellite measurements. However, they generally do not integrate surface measurements and thus remain affected by significant biases at ground level. In this study, we thoroughly evaluate two global atmospheric composition reanalyses, the Copernicus Atmosphere Monitoring Service (CAMSRA) and the Modern-Era Retrospective Analysis for Research and Applications v2 (MERRA-2), between 2003 and 2020, against independent surface measurements of O 3 , NO 2 , CO, SO 2 and particulate matter (PM; both PM 10 and PM 2.5) over the European continent. Overall, both reanalyses present significant and persistent biases for almost all examined pollutants. CAMSRA clearly outperforms MERRA-2 in capturing the spatiotemporal variability of most pollutants, as shown by generally lower biases (all pollutants except for PM 2.5), lower errors (all pollutants) and higher correlations (all pollutants except SO 2). CAMSRA also outperforms MERRA-2 in capturing the annual trends found in all pollutants (except for SO 2). Overall, CAMSRA tends to perform best for O 3 and CO, followed by NO 2 and PM 10 , while poorer results are typically found for SO 2 and PM 2.5. Higher correlations are generally found in autumn and/or winter for reactive gases. Compared to MERRA-2, CAMSRA assimilates a wider range of satellite products which, while enhancing the performance of the reanalysis in the troposphere (as shown by other studies), has a limited impact on the surface. The biases found in both reanalyses are likely explained by a combination of factors, including errors in emission inventories and/or sinks, a lack of surface data assimilation, and their relatively coarse resolution. Our results highlight the current limitations of reanalyses to represent surface pollution, which limits their applicability for health and environmental impact studies. When applied to reanalysis data, bias-correction methodologies based on surface observations should help to constrain the spatiotemporal variability of surface pollution and its associated impacts. [ABSTRACT FROM AUTHOR]

Carbon fiber reinforced composites (CFRP) and porous lattice structures possess the advantages of high specific strength and outstanding energy absorption efficiency. However, the structures combining their merits for underwater explosion protection receives little attention, and the underlying mechanics are still not clear. In this work, a CFRP-lattice sandwich structure is proposed, and its responses subjected to the underwater shock wave loading is studied via the finite element code ABAQUS/Explicit. The numerical results are first validated by the existing experiments (Huang et al., 2016), and the influences of the geometrical and load factors on the deformation modes and energy absorption performances are further explored. Results shows that with the variation of the load intensity and structural configuration, the failure modes of the plates can be mainly divided into three types. The failure occurs in the middle layer of the metal porous lattice core along the thickness direction. The thickness of the back plate has a greater influence on the overall deformation of the structure than that of the front plate. When the thickness of the back plate increases, the energy absorption of the front plate increases first and then decreases under the condition of a small shock wave load. The impact resistance of composite sandwich structure is the result of the coupling of core layer and plates. The proportion of energy absorption of each layer is affected by the form of structural energy transfer. The work of this paper provides guidance for the design of underwater protective equipment. • A novel CFRP-lattice sandwich structure was proposed. • The numerical and experiments results were in good agreement. • Three deformation modes of CFRP-lattice sandwich structure were summarized. • The effect of the geometrical factors and loading conditions on the energy absorption and deformation resistance performance were explored. • 71 various configurations were taken into consideration. [ABSTRACT FROM AUTHOR]

Objective The aim of this study was to investigate the correlations between body composition and traditional Chinese medicine (TCM) constitution in normal-weight, overweight, and obese outpatients in Department of Acupuncture for Endocrine-related Obesity. Methods The "YiJianZhong Weight Management" We Chat app was used to record patients' weight, TCM constitution (only five types of TCM constitutions were included: balanced constitution, phlegm-dampness constitution, damp-heat constitution, yang-deficiency constitution, and qi-stagnation constitution), and other information. In addition, a body composition analyzer was used to collect the information including the percentage of body fat, body mass index (BMI), basal metabolic rate, and visceral fat index. Finally, the body constitution data of patients with different TCM constitutions were summarized and analyzed. Results A total of 308 patients were included in the analysis, including 100 cases of normal-weight patients and 208 cases of obese or overweight patients. The proportions of TCM constitutions in the normal-weight patients were ranked from most to least as follows; balanced constitution > yang-deficiency constitution > damp-heat constitution > qi-stagnation constitution > phlegm-dampness constitution, while the proportions of TCM constitutions in obese and overweight patients were ranked in the same order as follows; balanced constitution > phlegm-dampness constitution > damp-heat constitution > yang-deficiency constitution > qi-stagnation constitution. There was no significant difference in the composition ratio of the different TCM constitutions between normal-weight patients and overweight, obese patients. The BMIs of all the patients were negatively correlated with the qi-stagnation constitution scores. The BMI decreased by 0.152 kg/m when the qi-stagnation constitution score increased by one point. The age and qi-stagnation constitution scores had a positive interaction with the BMI. For every 1-year increase in the average age of patients, the effect of the qi-stagnation constitution scores on the BMI changed from -0.152 kg/m to -0.147 kg/m. Conclusion In terms of the TCM constitution, a balanced constitution accounted for the highest proportion in normal-weight patients, overweight, and obese patients, while phlegm-dampness and damp-heat constitution accounted for a higher proportion in overweight and obese patients, except for the balanced constitution. In addition, in terms of the relationship between the TCM constitution and body composition, due to the negative correlation between the BMI and the qi-stagnation constitution score, overweight or obese patients with a qi-stagnation constitution should pay more attention to the influence of body composition indicators other than BMI on the development of disease. [ABSTRACT FROM AUTHOR]

In the context of global warming, most researches have been conducted on health influences of heat waves, with limited understanding of health impacts of cold spells, especially for developing countries. We collected daily mortality and meteorological data for 31 capital cities across China during the maximum period of 2007–2013. A quasi-Poisson regression model combined with a distributed lag non-linear model was used to estimate the short-term effects of cold spells on mortality in cold seasons (November to March). 19 definitions of cold spell were clearly compared, including three definitions from the China Meteorological Administration (CMA) and 16 definitions by combining two temperature indicators (daily minimum and mean temperature), two temperature thresholds (3rd and 5th percentile) and four durations of at least 2–5 days. Then, a random effect meta-analysis was applied to pool the effect estimates at national level. Furthermore, a stratified analysis was constructed to identify the vulnerable subpopulations to cold spells. The definition, in which daily mean temperature falls below 5th percentile for at least two consecutive days, produced the optimum model fit performance. Generally, the mortality risk increased to the maximum after 3–6 days' exposure to cold spell and then leveled off in the next 3 weeks. The pooled relative risks (RR) of non-accidental mortality for cold spells were 1.03 (95% CI: 1.01–1.05), 1.27 (1.19–1.35) and 1.55 (1.40–1.70) at lag 0, lag 0–14 and lag 0–27 days, respectively. The greatest effect estimates of cold spells were found among total respiratory diseases and COPD, with RR of 1.88 (1.65–2.11) and 1.88 (1.58–2.19), respectively. The elderly, less-educated individuals and residents in southern China were more vulnerable to cold spells. There are remarkable mortality effects of cold spells, with effect estimates varying with the definition of cold spell and subpopulations. Using the official definition of cold spells may fail to capture the mortality risk associated with cold spells. These findings may facilitate the development of cold alert warning system and preventive actions to the vulnerable populations. • This is the first multicity study to comprehensively examine health-related cold spell definitions in China. • Using the official cold spell definition failed to capture its mortality risk around China. • The elderly, respiratory patients, less-educated persons and residents in southern China were more vulnerable to cold spells. [ABSTRACT FROM AUTHOR]

This paper designs two chiral compression–twist coupling lattice structures with positive Poisson's ratio (PPR) and negative Poisson's ratio (NPR), and studies their compressive mechanical behaviors. Experiments and finite element (FE) simulations under the quasi-static load are firstly done. Compared to the PPR case, the maximum rotation of the lattice structure with the NPR effect is increased over 40%. Then dynamic compressive mechanical behaviors of the PPR and NPR lattice structures are investigated with different velocities of loads. Impact resistance performances of present structures are further researched, and gradient designs are introduced to improve the impact resistance performance. It is found that different Poisson's ratios show great effects on quasi-static and dynamic mechanical behaviors. As the velocity of load increases, both the initial deformation region and initial compact region are closer to the side of the applied load. Under the middle velocity load, the NPR lattice structure shows the smaller initial peak stress but less energy absorption. With the further increase of load velocity, the PPR lattice structure presents both the better energy absorption and smaller stress peak. The positive gradient (PG) rises the energy absorption, while the negative gradient (NG) abates the peak stress. As the NG design is used, the peak stress of the NPR lattice structure decreases from 23.3 MPa to 16.5 MPa. Besides, gradient designs diminish discrepancies of mechanical behaviors caused by different Poisson's ratios. • Two new chiral compression–twist coupling structures are designed and fabricated. • Quasi-static tests are done and gained results can be used as benchmark solution. • Dynamic compressive behaviors of the structures are studied for the first time. • Compression processes show new phenomena and meaningful conclusions are gained. • Gradient designs are introduced and the impact resistance performances are improved. [ABSTRACT FROM AUTHOR]

• Explore the impact of hourly temperature variability in 31 Chinese capital cities. • Investigate the time window of hourly temperature variability. • 5.47% of non-accidental mortality could be attributed to temperature variability. • Female, old, or undereducated people were more affected by temperature variability. • Effect of temperature variability may be modified by season and temperature zone. In the context of ongoing climate change, temperature variability (TV) has been considered as an important trigger of death. However, evidence of association between mortality and hourly temperature variability (HTV) is scarce at the multi-city level, and the time window of health effects of HTV is lack of investigation. This study aims at quantifying the mortality risk and burden of HTV and exploring subpopulations susceptible to HTV from a large-scale multi-city perspective. Data on daily number of deaths and meteorology were collected for 31 Chinese major cities during 2007–2013. HTV was calculated as the standard deviation of hourly temperature within a few days. The optimal exposure period of HTV was chosen according to multiple scientific criteria. A quasi-Poisson regression combined with distributed lag nonlinear model was used to assess the city-specific HTV-mortality associations. Then, meta-analysis was further applied to pool city-specific effect estimates. Finally, we calculated the fraction of mortality attributable to HTV. Stratification analyses were conducted by individual characteristics (i.e. age, sex, and educational attainment), season, and region. HTV calculated in a relatively long-time window like 18 d (HTV 0–17) could capture the impact of HTV adequately. Per 1 °C raise of HTV 0–17 associated with 1.38% (95%CI: 0.77, 1.99) increase of non-accidental mortality. During the study period, 5.47% (95%CI: 1.06, 9.64) of non-accidental mortality could be attributed to HTV. The females, the elderly, and individuals with low education level were more susceptible to HTV than their counterparts, respectively. Moreover, a stronger HTV-mortality association was observed in individuals who live in warmer season and temperature zone. HTV is associated with a considerable mortality burden, which may be modified by season, geographic and individual-level factors. Our findings highlight the practical importance of establishing early warning systems and promoting health education to mitigate the impacts of temperature variability. [ABSTRACT FROM AUTHOR]