The adhesion of soft connective tissues (tendons, ligaments, and cartilages) on bones in many animals can maintain high toughness (∽800 J m
) over millions of cycles of mechanical loads. Such ...fatigue-resistant adhesion has not been achieved between synthetic hydrogels and engineering materials, but is highly desirable for diverse applications such as artificial cartilages and tendons, robust antifouling coatings, and hydrogel robots. Inspired by the nanostructured interfaces between tendons/ligaments/cartilages and bones, we report that bonding ordered nanocrystalline domains of synthetic hydrogels on engineering materials can give a fatigue-resistant adhesion with an interfacial fatigue threshold of 800 J m
, because the fatigue-crack propagation at the interface requires a higher energy to fracture the ordered nanostructures than amorphous polymer chains. Our method enables fatigue-resistant hydrogel coatings on diverse engineering materials with complex geometries. We further demonstrate that the fatigue-resistant hydrogel coatings exhibit low friction and low wear against natural cartilages.
Electrochemical water splitting to produce hydrogen and oxygen, as an important reaction for renewable energy storage, needs highly efficient and stable catalysts. Herein, FeS2/CoS2 interface ...nanosheets (NSs) as efficient bifunctional electrocatalysts for overall water splitting are reported. The thickness and interface disordered structure with rich defects of FeS2/CoS2 NSs are confirmed by atomic force microscopy and high‐resolution transmission electron microscopy. Furthermore, extended X‐ray absorption fine structure spectroscopy clarifies that FeS2/CoS2 NSs with sulfur vacancies, which can further increase electrocatalytic performance. Benefiting from the interface nanosheets' structure with abundant defects, the FeS2/CoS2 NSs show remarkable hydrogen evolution reaction (HER) performance with a low overpotential of 78.2 mV at 10 mA cm−2 and a superior stability for 80 h in 1.0 m KOH, and an overpotential of 302 mV at 100 mA cm−2 for the oxygen evolution reaction (OER). More importantly, the FeS2/CoS2 NSs display excellent performance for overall water splitting with a voltage of 1.47 V to achieve current density of 10 mA cm−2 and maintain the activity for at least 21 h. The present work highlights the importance of engineering interface nanosheets with rich defects based on transition metal dichalcogenides for boosting the HER and OER performance.
FeS2/CoS2 interface nanosheets with rich defects show excellent electrocatalytic performance for hydrogen evolution reaction and oxygen evolution reaction in alkaline electrolytes. The overall water splitting device built with FeS2/CoS2 nanosheets as both cathode and anode also shows an excellent performance.
A patient's infectivity is determined by the presence of the virus in different body fluids, secretions, and excreta. The persistence and clearance of viral RNA from different specimens of patients ...with 2019 novel coronavirus disease (COVID-19) remain unclear. This study analyzed the clearance time and factors influencing 2019 novel coronavirus (2019-nCoV) RNA in different samples from patients with COVID-19, providing further evidence to improve the management of patients during convalescence.
The clinical data and laboratory test results of convalescent patients with COVID-19 who were admitted to from January 20, 2020 to February 10, 2020 were collected retrospectively. The reverse transcription polymerase chain reaction (RT-PCR) results for patients' oropharyngeal swab, stool, urine, and serum samples were collected and analyzed. Convalescent patients refer to recovered non-febrile patients without respiratory symptoms who had two successive (minimum 24 h sampling interval) negative RT-PCR results for viral RNA from oropharyngeal swabs. The effects of cluster of differentiation 4 (CD4)+ T lymphocytes, inflammatory indicators, and glucocorticoid treatment on viral nucleic acid clearance were analyzed.
In the 292 confirmed cases, 66 patients recovered after treatment and were included in our study. In total, 28 (42.4%) women and 38 men (57.6%) with a median age of 44.0 (34.0-62.0) years were analyzed. After in-hospital treatment, patients' inflammatory indicators decreased with improved clinical condition. The median time from the onset of symptoms to first negative RT-PCR results for oropharyngeal swabs in convalescent patients was 9.5 (6.0-11.0) days. By February 10, 2020, 11 convalescent patients (16.7%) still tested positive for viral RNA from stool specimens and the other 55 patients' stool specimens were negative for 2019-nCoV following a median duration of 11.0 (9.0-16.0) days after symptom onset. Among these 55 patients, 43 had a longer duration until stool specimens were negative for viral RNA than for throat swabs, with a median delay of 2.0 (1.0-4.0) days. Results for only four (6.9%) urine samples were positive for viral nucleic acid out of 58 cases; viral RNA was still present in three patients' urine specimens after throat swabs were negative. Using a multiple linear regression model (F = 2.669, P = 0.044, and adjusted R = 0.122), the analysis showed that the CD4+ T lymphocyte count may help predict the duration of viral RNA detection in patients' stools (t = -2.699, P = 0.010). The duration of viral RNA detection from oropharyngeal swabs and fecal samples in the glucocorticoid treatment group was longer than that in the non-glucocorticoid treatment group (15 days vs. 8.0 days, respectively; t = 2.550, P = 0.013) and the duration of viral RNA detection in fecal samples in the glucocorticoid treatment group was longer than that in the non-glucocorticoid treatment group (20 days vs. 11 days, respectively; t = 4.631, P < 0.001). There was no statistically significant difference in inflammatory indicators between patients with positive fecal viral RNA test results and those with negative results (P > 0.05).
In brief, as the clearance of viral RNA in patients' stools was delayed compared to that in oropharyngeal swabs, it is important to identify viral RNA in feces during convalescence. Because of the delayed clearance of viral RNA in the glucocorticoid treatment group, glucocorticoids are not recommended in the treatment of COVID-19, especially for mild disease. The duration of RNA detection may relate to host cell immunity.
This paper presents a novel implementation of an integral sliding-mode controller (ISMC) on a two-wheeled mobile robot (2 WMR). The 2 WMR consists of two wheels in parallel and an inverse pendulum, ...which is inherently unstable. It is the first time that the sliding-mode control method is employed for real-time control of a 2 WMR platform and several critical issues are addressed. First, the 2 WMR is underactuated, which uses only one actuator to achieve position control of the wheels while balancing the pendulum around the upright position. ISMC is suitable for control of the underactuated 2 WMR, because ISMC has an extra degree of freedom in control when sliding mode is achieved. In this paper, we utilize this extra degree of freedom to implement a linear nominal controller, which is found adequate in stabilizing the sliding manifold in a range around the equilibrium. Second, the 2 WMR system is in presence of both matched and unmatched uncertainties. The implemented ISMC, with an integral sliding surface and a switching term, is able to completely nullify the influence from the matched uncertainties. The implemented linear nominal controller stabilizes the sliding manifold that is subject to unmatched uncertainties. Third, references design are addressed when implementing ISMC on the 2 WMR. The effectiveness of ISMC is verified through intensive simulation and experiment results.
Baicalin, which is isolated from Radix Scutellariae, possesses strong biological activities including an anti-inflammation property. Recent studies have shown that the anti-inflammatory effect of ...baicalin is linked to toll-like receptor 4 (TLR4), which participates in pathological changes of central nervous system diseases such as depression. In this study, we explored whether baicalin could produce antidepressant effects via regulation of TLR4 signaling in mice and attempted to elucidate the underlying mechanisms.
A chronic unpredictable mild stress (CUMS) mice model was performed to explore whether baicalin could produce antidepressant effects via the inhibition of neuroinflammation. To clarify the role of TLR4 in the anti-neuroinflammatory efficacy of baicalin, a lipopolysaccharide (LPS) was employed in mice to specially activate TLR4 and the behavioral changes were determined. Furthermore, we used LY294002 to examine the molecular mechanisms of baicalin in regulating the expression of TLR4 in vivo and in vitro using western blot, ELISA kits, and immunostaining. In the in vitro tests, the BV2 microglia cell lines and primary microglia cultures were pretreated with baicalin and LY292002 for 1 h and then stimulated 24 h with LPS. The primary microglial cells were transfected with the forkhead transcription factor forkhead box protein O 1 (FoxO1)-specific siRNA for 5 h and then co-stimulated with baicalin and LPS to investigate whether FoxO1 participated in the effect of baicalin on TLR4 expression.
The administration of baicalin (especially 60 mg/kg) dramatically ameliorated CUMS-induced depressive-like symptoms; substantially decreased the levels of interleukin-1 beta (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α) in the hippocampus; and significantly decreased the expression of TLR4. The activation of TLR4 by the LPS triggered neuroinflammation and evoked depressive-like behaviors in mice, which were also alleviated by the treatment with baicalin (60 mg/kg). Furthermore, the application of baicalin significantly increased the phosphorylation of phosphatidylinositol 3-kinase (PI3K), protein kinase B (AKT), and FoxO1. The application of baicalin also promoted FoxO1 nuclear exclusion and contributed to the inhibition of the FoxO1 transactivation potential, which led to the downregulation of the expression of TLR4 in CUMS mice or LPS-treated BV2 cells and primary microglia cells. However, prophylactic treatment of LY294002 abolished the above effects of baicalin. In addition, we found that FoxO1 played a vital role in baicalin by regulating the TLR4 and TLR4-mediating neuroinflammation triggered by the LPS via knocking down the expression of FoxO1 in the primary microglia.
Collectively, these results demonstrate that baicalin ameliorated neuroinflammation-induced depressive-like behaviors through the inhibition of TLR4 expression via the PI3K/AKT/FoxO1 pathway.
Two pure silver nanoparticles (Ag210(iPrPhS)71(Ph3P)5Cl and Ag211(iPrPhS)71(Ph3P)6Cl labeled as SD/Ag210 and SD/Ag211 (SD=SunDi), were found to co‐crystallize in forming compound 1. Single‐crystal ...X‐ray diffraction (SCXRD) revealed that they differ by only one Ag(PPh3). Their four‐shell nanoparticles consist of three pure Ag metal shells (Ag19@Ag52@Ag45) shielded by a silver‐organic Ag89(iPrPhS)71ClAg(Ph3P)n outermost shell. The number (n) of Ag(Ph3P) is five for SD/Ag210 and six for SD/Ag211. The pseudo‐fivefold symmetric Ag nanoparticles exhibit surface plasmon absorption similar to a true metallic state but at the nanoscale. This work exemplifies the important effects of phosphine in stabilizing large silver nanoparticles; and offers a platform to investigate the origin of differences in nanoscale metal materials, even differing by only one metal atom; it also sheds light on the regioselective binding of auxiliary Ph3P on the surface of silver nanoparticles.
Two in one: Two different silver nanoparticles, Ag210(iPrPhS)71(Ph3P)5Cl and Ag211(iPrPhS)71(Ph3P)6Cl, differing by one Ag center, co‐crystallize in a single crystal. Both silver nanoparticles share the same Russian‐doll Ag19@Ag52@Ag45@Ag89 four‐shell motif covered by the same number of iPrPhS− and Cl− ligands.
Objectives
The purposes of this study were to clarify (i) the prevalence of pneumoconiosis among young adults and (ii) the factors associated with pneumoconiosis among young adults to explore ...targeted solution for control of pneumoconiosis among young adults (aged 24‐44 years).
Methods
The new cases diagnosed from 2001 to 2015 (extracted from the National Occupational Disease and Occupational Health Information Monitoring System) were involved in this research, including information of employer, patient's name, date of birth, gender, date of diagnosis, first year of dust exposure, duration of exposure, aggregation etc
Results
A total of 1519 pneumoconiosis cases were diagnosed among young adults (21.6% of overall cases). Silicosis was the most common type with acute process of disease. Compared with overall cases, the young patients had shorter duration of exposure, more stage II/III cases and higher aggravation rate; and were even more concentrated in small and medium enterprises where more migrant workers were employed and insufficient protective measures were used. Without further regulation, the prevalence of pneumoconiosis among young adults would bring not only disease suffering for 3000 individuals and their families, but also an annual economic loss up to 180 million yuan for Hebei province till 2025.
Conclusions
As a typical heavily industrialized province of China, Hebei has severe situation on pneumoconiosis among young adults. Special attention and effort on silica‐contacting industries, small and medium enterprises, and migrant workers should be focused in future occupational supervision and regulation among young adults.
•ED nurses exposed to COVID-19 could be psychologically and mentally exhausted.•Prevalence of depression among 1,103 ED nurses was 43.61% (95% CI=40.68%–46.54%).•A heightened awareness of and timely ...treatment for depression for frontline ED nurses should be provided.
Frontline medical staff exposed to the novel coronavirus disease (COVID-19) could be psychologically and mentally exhausted. This study examined the prevalence of depressive symptoms (depression hereafter) and their correlates and the association between depression and quality of life (QOL) in Emergency Department (ED) nurses during the COVID-19 pandemic in China.
This national, cross-sectional online survey was conducted between March 15 and March 20, 2020 in China. Depression and QOL were measured using the 9-item Patient Health Questionnaire, and the World Health Organization Quality of Life Questionnaire-Brief Version, respectively.
The overall prevalence of depression in 1103 ED nurses was 43.61% (95% CI=40.68–46.54%). Multiple logistic regression analysis revealed that working in tertiary hospitals (OR=1.647, P=0.009), direct patient care of COVID-19 patients (OR=1.421, P=0.018), and current smokers (OR=3.843, P<0.001) were significantly associated with depression. After controlling for covariates, nurses with depression had an overall lower QOL compared to those without (F(1,1103)=423.83, P<0.001).
Depression was common among ED nurses during the COVID-19 pandemic. Considering the negative impact of depression on quality of patient care and nurses’ QOL, a heightened awareness of, and early treatment for depression for frontline ED nurses should be provided.
The hidden structure of human enamel Beniash, Elia; Stifler, Cayla A; Sun, Chang-Yu ...
Nature communications,
09/2019, Letnik:
10, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Enamel is the hardest and most resilient tissue in the human body. Enamel includes morphologically aligned, parallel, ∼50 nm wide, microns-long nanocrystals, bundled either into 5-μm-wide rods or ...their space-filling interrod. The orientation of enamel crystals, however, is poorly understood. Here we show that the crystalline c-axes are homogenously oriented in interrod crystals across most of the enamel layer thickness. Within each rod crystals are not co-oriented with one another or with the long axis of the rod, as previously assumed: the c-axes of adjacent nanocrystals are most frequently mis-oriented by 1°-30°, and this orientation within each rod gradually changes, with an overall angle spread that is never zero, but varies between 30°-90° within one rod. Molecular dynamics simulations demonstrate that the observed mis-orientations of adjacent crystals induce crack deflection. This toughening mechanism contributes to the unique resilience of enamel, which lasts a lifetime under extreme physical and chemical challenges.
Closed-loop data are widely encountered in modern industrial systems, which require special data analytics to gain insight for system monitoring. A closed-loop dynamic latent analysis scheme named ...closed-loop DiCCA (CL-DiCCA) is proposed in this article. Bidirectional dynamic latent variable relationships are proposed with a new objective to extract the closed-loop dynamic latent structure. An iterative algorithm is proposed to solve the constructed optimization problem for closed-loop processes. Four statistically independent residuals are generated, which monitor the dynamic and static variations of the process data. A process monitoring logic with the CL-DiCCA model is established, which offers further separation of faults into output-relevant and output-irrelevant ones. A numerical simulation and a case study on the thruster system of the Jiaolong deep-sea submersible are provided to illustrate the effectiveness of the proposed method.
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