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Background: Single measures of self-reported nighttime sleep duration and daytime napping duration are associated with adverse health outcomes; However, the association between longitudinal patterns of self-reported nighttime sleep duration and daytime napping duration and multimorbidity remains unclear. We therefore undertook cox regression analyses to explore linkages between sleep trajectories and multimorbidity.Methods: The current study included 5262 participants from China Health and Retirement Longitudinal Study. Self-reported nighttime sleep duration and daytime napping duration were collected from 2011 to 2015. The 4-year sleep duration trajectories were conducted by group-based trajectory modelling. The fourteen medical conditions were diagnosed by self-reported physicians or identified by combining health assessment and medication data. Multimorbidity was diagnosed as Participants with two or more of the 14 chronic diseases after 2015. Associations between sleep trajectories and multimorbidity were assessed by cox regression models.Results: During 6.69 years of follow-up, we observed multimorbidity in 785 participants. Four nighttime sleep duration trajectories and three daytime napping duration trajectories were identified. Participants with persistent short nighttime sleep duration trajectory had the higher risk of multimorbidity (Hazard ratio (HR)=1.24, 95% confidence interval (CI): 1.04-1.49), compared with those with persistent normal nighttime sleep duration trajectory. We have not found a benefit of daytime napping on the development of multimorbidity. Participants with persistent normal nighttime sleep duration and persistent seldom daytime napping duration had a lower risk of multimorbidity.Conclusions: In this study, persistent short nighttime sleep duration trajectory was associated with subsequent multimorbidity risk. Daytime napping cannot fully compensate for the risk of insufficient night sleep.

Background Organosolv pretreatment is one of the most efficient methods for delignification and boosting biomass saccharification. As compared to typical ethanol organosolv pretreatments, 1,4-butanediol (BDO) organosolv pretreatment is a high-boiling-point solvent pretreatment, which can generate low pressure in the reactor during high temperature cooking that improves the operation safety. Although several studies showed that organosolv pretreatment can lead to effective delignification and enhancement in glucan hydrolysis, there has been no studies on acid- and alkali-catalyzed BDO pretreatment, as well as their comparison on promoting biomass saccharification and lignin utilization. Results It was shown that BDO organosolv pretreatment was more effective in removing lignin from poplar as compared with typical ethanol organosolv pretreatment under the same pretreatment conditions. HCl-BDO pretreatment with 40 mM acid loading led to 82.04% of original lignin removed from biomass, as compared to the lignin removal of 59.66% in HCl-Ethanol pretreatment. Besides, acid-catalyzed BDO pretreatment was more effective in improving the enzymatic digestibility of poplar than alkali-catalyzed BDO pretreatment. As a result, HCl-BDO with acid loading of 40 mM provided a good enzymatic digestibility of cellulose (91.16%) and the maximum sugar yield of 79.41% from original woody biomass. The linear correlations between physicochemical structure (e.g., fiber swelling, cellulose crystallinity, crystallite size, surface lignin coverage and cellulose accessibility) changes of BDO pretreated poplar and enzymatic hydrolysis were plotted to figure out the main factors that influenced biomass saccharification. Moreover, acid-catalyzed BDO pretreatment mainly brought about the phenolic hydroxyl (PhOH) groups formation in lignin structure, while alkali-catalyzed BDO pretreatment mostly led to the lower molecular weight of lignin. Conclusions Results indicated that the acid-catalyzed BDO organosolv pretreatment could significantly improve enzymatic digestibility of the highly recalcitrant woody biomass. The great enzymatic hydrolysis of glucan resulted from increased cellulose accessibility, which mostly associated with the higher degree of delignification and hemicellulose solubilization, as well as the more increase in fiber swelling. Besides, lignin was recovered from the organic solvent, which could be used as natural antioxidants. The formation of phenolic hydroxyl groups in lignin structure and the lower molecular weight of lignin contributed to its greater radical scavenging capacity.

Objective: Our present study utilizes case-control research to explore the relationship between specific CircRNA and pediatric obesity through literature review and bioinformatics, and predict its possible biological functions, providing ideas for epigenetic mechanisms study of pediatric obesity. Methods: CircRNAs related to pediatric obesity were preliminarily screened by literature review and qRT-PCR. CircRNAs expression in obesity children (n=75) and controls (n=75) were confirmed with qRT-PCR in case-control study, followed by bioinformatics analyses, such as GO analysis, KEGG pathway analysis, and CeRNA network construction. Multivariate logistic regression was utilized to analyze the effects of CirRNAs on obesity. Receiver operating characteristic (ROC) curve was further drawn to explore the clinical application value of CircRNAs in pediatric obesity. Results: hsa_circ_0046367 and hsa_circ_0000284 were separately validated to be statistically down-regulated and up-regulated in the peripheral blood mononuclear cells of obesity children, and revealed as independent indicators of increased CHD risk [hsa_circ_0046367(OR=0.681, 95%CI: 0.480~0.967) and hsa_circ_0000284 (OR=1.218, 95%CI:1.041~1.424)]. The area under the ROC curve in the combined analysis of hsa_circ_0046367 and hsa_circ_0000284 was 0.706(95%CI:0.623~0.789). Enrichment analyses revealed that they were actively involved in Neural Plasticity mechanisms, Cell Secretion and Signal Regulation. Conclusion: The present research disclosed that low expression of hsa_circ_0046367 and high expression of hsa_circ_0000284 are risk factors for pediatric obesity, neural plasticity mechanisms was closely related to obesity.

As a key component of lithium-ion batteries (LIBs), separator plays a crucial role in the performance and safety of LIBs. In this paper, a cellulose based porous membrane modified by nano CaCO3 is prepared conveniently by electrospinning. The membrane exhibits rich fibrous porous networks and uniform distribution of nanoparticles. Strengthed by CaCO3, the tensile strength of the cellulose porous membrane elevates from 4.7 ± 0.4 MPa to 7.7 ± 0.7 MPa. Besides, the modified membranes possess improved thermal stability and can maintain their original size after treatment at 150 °C and 180 °C. Also, the electrolyte uptake of cellulose/CaCO3 membrane is 73% higher than that of the pure cellulose membrane. Thus, the ionic conductivity of membrane achieves 1.08 mS cm-1 and the electrochemical window is about 4.8V, which meets the practical requirements of LIBs. Significantly, LiFePO4/Li battery this membrane can run for 230 cycles with a capacity retention of 97.4% and a discharge capacity of 149.0 mAh g-1, demonstrating the huge potential for high safety and next-generation LIBs.

Cold spray is an attractive and rapidly developing process for additive manufacturing with high efficiency and precision, repairing and coating, especially in aircraft and aerospace applications. Cold spray additive manufacturing deposits micro-particles with large plastic deformation below their melting point, eliminating heat effect zone which could deteriorate the quality of repairing zone. The particle deposition in cold spray is a complex process which involves high strain rate, high contact pressure and high temperature. Here we develop, utilize and validate a thermo-mechanical model to provide a definitive way to predict deposition mechanics and surface deformation evolution for particle deposition process in cold spray additive manufacturing. Both a single particle and dual particles models were developed to investigate the contact interaction between particle/substrate and particle/particle. Different combinations of particle/substrate materials (Cu/Cu, Al/Al, steel/steel, and nickel/nickel) and process parameters were considered in this study. The experimental study was conducted to validate simulation results, providing useful information for understanding the limitations and challenges associated with cold spray additive manufacturing. The framework provides insights into improving the quality and precision of stress/strain formation, particle interactions and particle deposition in cold spray additive manufacturing process.

Monochromaticity for light-emitting diodes (LEDs) is an important parameter. However, carbon dots-based light-emitting diodes (CDs-LEDs) usually suffer from broad emission, which limits the development of this material. In this work, high-quality carbon dots (CDs) with a quantum yield of 16.2% were synthesized. When they were mixed with poly(

The micro-defects on KH2PO4 (KDP) optic surfaces are mainly repaired by the micro-milling technique, while it is very easy to introduce brittle cracks on repaired surfaces, as KDP is soft and brittle. To estimate machined surface morphologies, the conventional method is surface roughness, but it fails to distinguish ductile-regime machining from brittle-regime machining directly. To achieve this objective, it is of great significance to explore new evaluation methods to further characterize machined surface morphologies. In this study, the fractal dimension (FD) was introduced to characterize the surface morphologies of soft-brittle KDP crystals machined by micro bell-end milling. The 3D and 2D fractal dimensions of the machined surfaces and their typical cross-sectional contours have been calculated, respectively, based on Box-counting methods, and were further discussed comprehensively by combining the analysis of surface quality and textures. The 3D FD is identified to have a negative correlation with surface roughness (Sa and Sq), meaning the worse the surface quality the smaller the FD. The circumferential 2D FD could quantitively characterize the anisotropy of micro-milled surfaces, which could not be analyzed by surface roughness. Normally, there is obvious symmetry of 2D FD and anisotropy on the micro ball-end milled surfaces generated by ductile-regime machining. However, once the 2D FD is distributed asymmetrically and the anisotropy becomes weaker, the assessed surface contours would be occupied by brittle cracks and fractures, and corresponding machining processes will be in a brittle regime. This fractal analysis would facilitate the accurate and efficient evaluation of the repaired KDP optics by micro-milling.

BackgroundMultimorbidity has become an important public health problem in China, especially among middle-aged and elderly women. Few studies have been reported on the association between multimorbidity and female fertility, which is an important stage in the life course. This study aimed to explore the association between multimorbidity and fertility history among middle-aged and elderly women in China.MethodsData from 10,182 middle-aged and elderly female participants in the China Health and Retirement Longitudinal Study (CHARLS) in 2018 were used in this study. Multimorbidity was defined as the presence of at least two or more chronic conditions. Logistic regression analysis, negative binomial regression analysis, and restrictive cubic splines (RCSs) were used to analyze the relationship between female fertility history and multimorbidity or the number of chronic conditions. Multivariable linear regression was used to analyze the relationship between female fertility history and multimorbidity pattern factor scores.ResultsThe results of this study showed that high parity and early childbearing were significantly associated with an increased risk of multimorbidity and an increased number of chronic conditions among middle-aged and elderly women in China. Late childbearing was significantly associated with reduced risk of multimorbidity and lessened diseases. Parity and age of first childbirth were significantly correlated with the odds of multimorbidity. The association between fertility history and multimorbidity was found to be influenced by age and urban–rural dual structure. Women with high parity tend to have higher factor scores of cardiac-metabolic, visceral-arthritic, and respiratory-psychiatric patterns. Women with early childbearing tended to have higher factor scores of the visceral-arthritic pattern and those with late childbearing tended to have lower factor scores of the cardiac-metabolic pattern.ConclusionFertility history has a significant effect on multimorbidity in the middle and later lives of Chinese women. This study is of great importance for reducing the prevalence of multimorbidity among Chinese women through their life course and promoting health during their middle and later lives.

The oxygen vacancy modulated a-WO3−x enables independent control of VIS and NIR light and has great application potential in high-performance smart windows.

Nuclear magnetic resonance (NMR) is widely used to characterize the pore structure of rock. The nanoscale pores and fractures are well developed in a shale gas reservoir. The closure of nanopores caused by the increase in effective stress during the gas production process could induce stress sensitivity in shale nanopores, which has a great impact on the single-well productivity in the middle–late development stage. In this paper, shale samples from the Longmaxi Formation were taken to investigate the nanopore stress sensitivity via an NMR method. Samples with different degrees of pore and fracture development were selected and NMR experiments under different effective stress conditions were carried out. The results show that: (1) As the effective stress increases, the pore space in shale is continuously compressed, and the cumulative pore volume of shale decreases; (2) There is a more pronounced decrease in the cumulative pore volume of samples containing larger pores with the increase in effective stress. However, there are obvious differences in the pore volume changes in different pore sizes; (3) The transformation of nanopores of different sizes occurs in the process of effective stress loading. When the effective stress is small, the pores with diameters larger than 50 nm are mainly transformed to those with diameters of 10–50 nm. When the effective stress increases to a certain extent, the pores with diameters of 10–50 nm are mainly transformed to those with diameters of 0–10 nm; (4) There are significant differences in the compressibility of nanopores of different sizes. Larger nanopores generally have a higher compression coefficient and a stronger stress sensitivity. In the process of effective stress loading, the compression coefficient of pores with diameters between 10 and 50 nm changes relatively slowly, which can well-maintain the pore shape and quantity. Based on the variation in porosity ratio with effective stress, a new method of dividing shale nanopores is proposed; those with diameters smaller than 10 nm, those with diameters of 10–50 nm, and those with diameters larger than 50 nm.

Objectives: To explore the association between nutrient supplements and the prevalence of depression. To explore the mediating role of physical exercise in this association. Methods:Data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS) were analyzed. A total of 8,427 older adults were included in this study. We used the Center for Epidemiologic Studies Depression Scale (CES-D-10) to assess participants' depression, self-reported use of nutrient supplements as exposure, and self-reported exercise habits to assess participants' physical activity. Logistic regression was used to analyze the association between nutrient supplements and depression. Mediation analysis was used to explore the role of physical activity in this association. Results: This study found that the use of nutrient supplements was associated with a lower prevalence of depression (OR=0.641, 95% confidence interval [CI]: 0.536-0.766). The prevalence of depression was lower among those who used one or more nutrient supplements compared with those who did not use nutrient supplements. Among the 8 nutrient supplements, calcium, vitamin A/D and other nutrient supplements played a greater role. And physical exercise played a mediating role in the association of nutrient supplements with depression. Conclusions:Using nutrient supplements could reduce the risk of depression. While using supplements, people should be exercising to promote absorption.

Hydraulic fracturing of shale gas reservoirs is characterized by large fracturing fluid consumption, long working cycle and low flowback efficiency. Huge amounts of fracturing fluid retained in shale reservoirs for a long time would definitely cause formation damage and reduce the gas production efficiency. In this work, a pressure decay method was conducted in order to measure the amount of fracturing fluid imbibition and sample permeability under the conditions of formation temperature, pressure and adsorbed methane in real time. Experimental results show that (1) the mass of imbibed fracturing fluid per unit mass of shale sample is 0.00021–0.00439 g/g considering the in-situ pressure, temperature and adsorbed methane. (2) The imbibition and flowback behavior of fracturing fluid are affected by the imbibition or flowback pressure difference, pore structure, pore surface properties, mechanical properties of shale and mineral contents. (3) 0.01 mD and 0.001 mD are the critical initial permeability of shales, which could be used to determine the relationship between the formation damage degree and the flowback pressure difference. This work is beneficial for a real experimental evaluation of shale formation damage induced by fracturing fluid.

When serving in extremely high-power laser conditions, KH2PO4 (KDP) surfaces are susceptible to incur laser damage points (also known as defects). Using micro-ball end milling cutters to repair and remove the pre-existing damage points on the flawed KDP crystal surface is the most effective method to control the growth of laser damage points on KDP crystal surfaces and prolong their service life. However, there are various forms of micro-defects (such as pits, scratches and brittle fractures) around the laser damage points on KDP crystal surfaces which possess remarkable effects on the micro-milling repair process and consequently deteriorate the repair quality. In this work, combined with nano-indentation experiments, elastic–plastic mechanics and fracture mechanics theory, a constitutive model considering the anisotropic property of KDP crystals and a three-dimensional (3D) finite element model (FEM) were established to simulate the cutting force and surface topography involved in the ball-end milling repairing of flawed KDP crystal surfaces. Besides, the micro-milling experiments were conducted to evaluate the change of cutting force and machined surface quality in the presence of micro-defects with various feed rates. The results show that micro-defects would induce the fluctuation of cutting force and a change of the undeformed cutting thickness (UCT) in the process of repairing the damage points on the crystal surface, which would lead to the brittle–ductile transition (BDT) and affect the machined surface quality. The machined surface quality was found to be deteriorated by the pre-existing micro-defects when the UCT was small (the UCT was less than 375 nm). On the contrary, brittle mode cutting in the local area can be transformed into ductile mode cutting, resulting in an improvement of repaired surface quality that is exhibited by the cutting force and microtopography. This work has great theoretical significance and engineering practical value for the promotion and application of micro-milling repairing technology in the practical manufacturing and operation of KDP optics applied to high-power laser systems.

Up to now, micro milling has been recognized as the most promising technique to mitigate the surface damage of large-aperture KDP crystal used in laser fusion facility. However, there are quantities of damages on the surface of large-aperture KDP crystal to be mitigated. Furthermore, the efficiency and accuracy of manual tool setting is relatively low, and it is easy to damage KDP crystal surface due to mis-operation. Therefore, an automatic tool setting technology for KDP crystal surface damage mitigation based on machine vision is proposed in this research. The automatic tool setting includes fast pre tool setting achieved by image ranging and final tool setting achieved by micro-chip detection. In the process of fast pre tool setting, real-time image of the micro milling cutter is obtained, and the distance between the tool tip and the KDP crystal surface is obtained by image ranging. Finally, the tool tip is quickly positioned 20 μm away from the KDP crystal surface. In the process of final tool setting, the micro milling cutter is retreated to a distance of about 50 μm away from the KDP crystal surface before detecting micro-chips. Therefore, the micro-chips covered by the micro milling cutter will be exposed and appear in the view field of microscope, so as to improve the micro-chip recognition rate. The results showed that the total time of automatic tool setting is 130 s, and the accuracy of automatic tool setting is better than 1.359 μm. Compared with manual tool setting, the automatic tool setting based on machine vision proposed in this research improves the safety, efficiency, and accuracy of independently developed mitigation system for KDP crystal surface damage.

As for ultra-precision grinding of difficult-to-process thin-walled complex components with ball-end grinding wheels, interference is easy to occur. According to screw theory and grinding kinematics, a mathematical model is established to investigate the interference and grinding characteristics of the ball-end wheel. The relationship between grinding wheel inclination angle, C axis rotation angle, grinding position angle and grinding wheel wear are analyzed. As the grinding wheel inclination angle increases, the C axis rotatable range decreases and the grinding position angle increases. The grinding position angle and wheel radius wear show a negative correlation with the C axis rotation angle. Therefore, a trajectory planning criteria for increasing grinding speed as much as possible under the premise of avoiding interference is proposed to design the grinding trajectory. Then grinding point distribution on the ball-end wheel is calculated, and the grinding characteristics, grinding speed and maximum undeformed chip thickness, are investigated. Finally, a complex structural component can be ground without interference, and surface roughness and profile accuracy are improved to 40.2 nm and 0.399 μm, compared with 556 nm and 3.427 μm before ultra-precision grinding. The mathematical model can provide theoretical guidance for the analysis of interference and grinding characteristics in complex components grinding to improve its grinding quality.

Intrinsic defects introduced by manufacturing-induced lateral cracks have a great influence on the laser damage of KDP crystals. VO defects reduce the laser-induced damage threshold and VH defects exacerbate the damage growth under laser irradiation.

With the development of society and the economy, there is an increasing demand for surface treatment techniques that can efficiently utilize metal materials to obtain good performances in the fields of mechanical engineering and the aerospace industry. The laser metal deposition (LMD) technique for cladding has become a research focus in recent years because of its lower dilution rate, small heat-effect zone and good metallurgical bonding between the coating and substrate. This paper reviews the simulation technology for the melt pool’s grain growth mechanism, temperature and stress distribution that are directly related to defect formation in LMD technology. At the same time, the defect suppression method and the performance improvement method of the cladded layer in LMD technology are introduced. Finally, it is pointed out that the active selection of materials according to the required performance, combined with the controllable processing technology, to form the corresponding microstructure, and finally, to actively realize the expected function, is the future development direction of LMD technology.

CircRNAs have been shown to be involved in the development of certain diseases, but their application in prehypertension and hypertension remains unclear. We aimed to explore the potential role of circ_0000284 in revealing the molecular regulatory mechanisms of prehypertension and hypertension. We enrolled a total of 100 patients with normal blood pressure, 100 patients with prehypertension and 100 patients with hypertension. The expression of circ_0000284 among the groups was detected by real-time fluorescence quantitative polymerase chain reaction (qRT‒PCR). Multivariate logistic models were constructed combining conventional risk factors with circ_0000284. A receiver operating characteristic curve (ROC) was used to analyze the diagnostic value of circRNAs in the clinical model. Spearman correlation was used to analyze the correlation of circ_0000284 and the biochemical characteristics of all subjects. The results showed that circ_0000284 was differentially expressed among the normal blood pressure group, prehypertensive group and hypertensive group and showed a significantly upregulated trend in the progression to hypertension (P 0.05). The ROC curve revealed a high diagnostic ability of circ_0000284 in hypertension in the clinical model (AUC = 0.812). Circ_0000284 also presented a certain ability for early diagnosis of prehypertension (AUC = 0.628). Spearman correlation showed that circ_0000284 was positively correlated with Na and CKMB. Our study suggested that upregulated expression of circ_0000284 was an independent risk factor for prehypertension and hypertension. Circ_0000284 was a potential fingerprint for the early diagnosis of hypertension and distinguished the intermediate stage of hypertension development. Moreover, our study provided new insight into the correlation between circ_0000284 and cardiac injury in the progression to hypertension.

Several studies have reported an association between residential surrounding particulate matter with an aerodynamic diameter ≤2.5 μm (PM

When a fracturing fluid invades a nanoscale shale pore structure, it will inevitably affect the ad-/desorption behavior of methane adsorbed on a shale pore wall, impacting the overall methane produ...

A large amount of fracturing fluid retained in a shale gas reservoir that does not flow back after hydraulic fracturing could induce formation damage of aqueous phase trapping (APT). A shale gas re...

In this study, the cellular microstructural features in a subgrain size of carbon nanotube (CNT)-reinforced aluminum matrix nanocomposites produced by laser powder bed fusion (LPBF) (a size range between 0.5–1 μm) were quantitatively extracted and calculated from scanning electron microscopy images by applying a cell segmentation method and various image analysis techniques. Over 80 geometric features for each cellular cell were extracted and statistically analyzed using machine learning techniques to explore the structure–property linkages of carbon nanotube reinforced AlSi10Mg nanocomposites. Predictive models for hardness and relative mass density were established using these subgrain cellular microstructural features. Data dimension reduction using principal component analysis was conducted to reduce the feature number to 3. The results showed that even AlSi10Mg nanocomposite specimens produced using different laser parameters exhibited similar Al–Si eutectic microstructures, displaying a large difference in their mechanical properties including hardness and relative mass density due to cellular structure variance. For hardness prediction, the Extra Tress regression models showed a relative error of 2.47% for prediction accuracies. For the relative mass density prediction, the Decision Tress regression models showed a relative error of 1.42% for prediction accuracies. The results demonstrate that the developed models deliver satisfactory performance for hardness and relative mass density prediction of AlSi10Mg nanocomposites. The framework established in this study can be applied to the LPBF process optimization and mechanical properties manipulation of AlSi10Mg-based alloys and other additive manufacturing newly designed alloys or composites.

In this study, transverse heat flow suppression (THFS) technique was proposed to enhance the ability of thermal-wave radar thermography (TWRT) to resist lateral thermal diffusion and uneven heating. The enhanced TWRT was used to detect subsurface defects of carbon fiber reinforced plastic (CFRP) laminates. The principle of THFS was described in detail by the optical flow analogy. The three-dimension (3-D) thermal-wave model stimulated by the uneven linear frequency modulation (LFM) thermal flow was introduced. The thermal-wave signal was processed by several different postprocessing characteristic extraction algorithms [Cross-correlation algorithm (CC), dual-orthogonal demodulation algorithm (DOD), fractional Fourier transform (FrFT), and principal component analysis (PCA)]. The comparison between normalized DOD amplitude/phase and normalized DOD-THFS amplitude/phase was carried out. The simulation results depicted THFS can significantly improve the difference between defect location and nondefect location. Nine CFRP specimens with artificial flat-bottom holes (FBHs) were prepared for nondestructive testing and evaluation (NDT&E) by enhanced TWRT. Seventy-two FBHs were prepared to test the probability of detection (PoD) of the enhanced TWRT. Hit/miss method was used to count defect information. The results demonstrated that the enhanced TWRT can realize the effective detection of defects (90% detection probability) with a diameter depth ratio of 5.06 under 95% confidence level. Compared with two state-of-the-art approaches, the proposed DOD-THFS phase has a better defect detection signal-to-noise ratio (SNR).