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Bone malunion or nonunion leads to functional and esthetic problems and is a major healthcare burden. Activation of bone marrow mesenchymal stem cells (BMSCs) and subsequent induction of osteogenic differentiation by local metabolites are crucial steps for bone healing, which has not yet been completely investigated. Here, we found that lactate levels are rapidly increased at the local injury site during the early phase of bone defect healing, which facilitates the healing process by enhancing BMSCs regenerative capacity. Mechanistically, lactate serves as a ligand for the Olfr1440 olfactory receptor, to trigger an intracellular calcium influx that in turn activates osteogenic phenotype transition of BMSCs. Conversely, ablation of Olfr1440 delays skeletal repair and remodelling, as evidenced by thinner cortical bone and less woven bone formation in vivo. Administration of lactate in the defect area enhanced bone regeneration. These findings thus revealed the key roles of lactate in the osteogenic differentiation of BMSCs, which deepened our understanding of the bone healing process, as well as provided cues for a potential therapeutic option that might greatly improve bone defect treatment. [ABSTRACT FROM AUTHOR]

Cu–Y 2 O 3 composites were prepared by a secondary mechanical ball milling process and liquid phase in situ reaction and then sintered by the spark plasma sintering (SPS) consolidation technique. The microstructure and mechanical properties were studied using an X-ray powder diffractometer, scanning electron microscope, tensile tester, and Vickers hardness tester. The results showed that the added yttrium was converted into Y 2 O 3 , and the obtained Y 2 O 3 nano-particles were uniformly distributed in the copper matrix, their mean size was 5.0 nm, and the cubic Y 2 O 3 phase was coherent with the copper matrix, which indicated (422)Y 2 O 3 // (1 ‾ 11) Cu and [ 01 1 ‾ ] Y 2 O 3 // [ 1 1 ‾ 2 ] Cu orientation relationship. With the addition of Y, the mechanical properties of the composite materials were improved, and the hardness of 10 vol% Y 2 O 3 was increased by 192.0%. Its tensile strength increased by 168.2% compared to pure copper. [ABSTRACT FROM AUTHOR]

• Ant colonization reduced soil organic carbon storage and stability. • Mineralization of soil organic carbon was greatly accelerated by ant colonization. • Ant mounds served as methane sinks while nearby soils were methane sources. • Ants could effectively form soil organic carbon heterogeneity at microscales. Acting as ecosystem engineers, ant activities are significantly crucial in altering carbon (C) cycles by modifying the energy flows and nutrient cycles in soils. However, how ant mound constructions reshape soil organic carbon (SOC) pool heterogeneity and stability remains elusive. In this study, we compared differences in soil properties, vegetation biomass, greenhouse gas (GHG) emission, and molecular composition of SOC between ant mounds and nearby soils from a drained peatland, intending to decipher factors that govern carbon dynamics during ant excavates. Results indicated that ant mound construction simultaneously caused a decrease in SOC contents and an increase in nutrient level (total nitrogen and phosphorus), dissolved organic carbon (DOC), and its proportion to SOC (DOC/SOC) dramatically. The proportions of pyrolytic products derived from lignin, phenol, and aromatics decreased significantly from 31.70 % in nearby soils to 27.43 % in ant mounds. However, no significant difference in iron-bound organic carbon (OC-Fe) was found between ant mounds and nearby soils (p > 0.05). Ant mound building greatly accelerated SOC mineralization, with average CO 2 emission fluxes 1–2 times higher than that in nearby soils. Notably, CH 4 emissions from ant mounds was negative, meaning ant mounds acted as CH 4 sinks. Meanwhile, net CH 4 flux emission into the atmosphere from nearby soils were positive. Both plant biomass and SOC density (SOC d) in ant mounds were considerably lower than those observed in nearby soils. The structural equation model indicated that soil nutrient enrichment in ant mounds indirectly stimulated SOC decomposition by stimulating microbial abundance. Still, ant mounds construction had direct positive effects on labile carbon components accumulation and posed negative effects on resistant SOC compounds. Moreover, redundancy analysis and variation partitioning analysis confirmed that SOC d decline in ant mounds was primarily attributed to reduced soil moisture and elevated microbial abundance. The conceptual model implied that ants could effectively strengthen SOC content heterogeneity at the microscales, characterized by lower SOC storage and stability, and higher CO 2 emission than those in nearby soils. [ABSTRACT FROM AUTHOR]

Axial turbine is a key device which influences the power output and efficiency of the Compressed Air Energy Storage (CAES) system notably. In present study, the effect of chamber roughness on the efficiency and flow loss characteristics of an axial turbine in the CAES system is investigated numerically to find a way to improve the performance and reduce the manufacturing cost. The results illustrate that the efficiency is reduced nonlinearly with the increase of chamber roughness. An efficiency reduction of 0.45% is obtained when chamber roughness is less than 10 μm at design point. However, the efficiency reduction of 1.9% is obtained by the chamber roughness of 50 μm when the expansion ratio is less than 1.9. Internal flow analysis reveals that the passage vortex near upper end wall in the left-part of stator ring is strengthen with the increase of chamber roughness. An efficiency recovery of 0.61% is achieved by "Local smoothing wall" which has wall roughness of 1.6 μm at only 11.26% of the wall area. The isentropic efficiency is also increased more than 0.6% compared to the full smooth wall wall when total pressure ratio is 1.4. • Efficiency of turbine is decreased with the increase of chamber roughness nonlinearly. • Obvious efficiency reduction of 0.45% is observed when wall roughness is less than 10 μm. • Efficiency reduction of 1.9% is found when total pressure ratio is less than 1.9. • Different flow loss characteristics are found in the stator passage along circumferential direction. • Efficiency increment of 0.61% is achieved by chamber with "local smoothing wall". [ABSTRACT FROM AUTHOR]

Self-healing hydrogel systems usually suffer from poor mechanical performance stemmed from weaker and reversible non-covalent interactions or dynamic chemical bonds, which hamper their practical applications. This issue is addressed by adopting a double-crosslinking design involving both dynamic Schiff base bonds and non-dynamic photo-induced crosslinking. This leads to the formation of a special topological structure which simultaneously provide good self-healing capability and enhanced mechanical performance (elastic recovery and tensile modulus of 157.4 kPa, close to modulus of native skin). The quaternary ammonium and protonated amino groups can provide superior antibacterial capability; and Schiff base formation between residual aldehyde groups and amino groups on tissue surface contribute to hydrogel's adhesion to tissues (5.9 kPa). Furthermore, the multifunctional hydrogels with desirable mechanical performance, self-healing capability, superior antibacterial capability and tissue adhesion can significantly promote healing of infectious cutaneous wound, tissue remodeling and regeneration. [Display omitted] [ABSTRACT FROM AUTHOR]

Fluorescent carbon nanodots (CNDs) have exhibited attractive potential for biomedical applications due to their intriguing luminescent properties and good biocompatibility. One interesting property of CNDs is that they typically show different emission colors upon optical excitation using different wavelengths. However, it is still a challenge to obtain emissions covering the entire visible spectrum with comparable intensity with only one type of CND. Herein, CNDs with tunable full-color luminescence are successful prepared by a solvothermal approach, show broad absorption (200–700 nm) and fluorescence emission (nearly cover the entire visible region: from 400 to 700 nm) with comparable fluorescence intensities. The oxidation (o-CNDs) and reduction (r-CNDs) of CNDs surface would lead to the shifting of photoluminescence band into blue/green and red-light region, respectively. Further spectroscopic analyses and structural characterizations of CNDs (pristine state), o-CNDs (oxidation state) and r-CNDs (reduction state) demonstrate that O-related defect states (C O) and N-related defect states (C N) on surface of CNDs should be responsible for blue/green and red fluorescence emissions, respectively. Moreover, the CNDs are found to be biocompatible, as verified by in vitro cells assay and in vivo histological analysis. In vivo fluorescence imaging assay demonstrates that CNDs can be excreted through intestine and bladder system. The tunable full-color emission, good biocompatibility and metabolism suggest that the CNDs are promising fluorescent probes for biomedical applications. Carbon nanodots with tunable full-color luminescence can be controlled by oxygen/nitrogen-related surface state, and can serve as optical fluorescence nanoprobes in multicolor bio-imaging. Image 1 [ABSTRACT FROM AUTHOR]

Abstract Objectives We aim to examine whether nonpharmacological interventions could effectively improve depressive symptoms and depression to provide more treatment options for nursing students. Methods PubMed, the Cochrane Library, EMBase, Web of Science, PsycINFO, and three Chinese electronic databases were comprehensively searched for papers that were published from January 1990 through March 2018. Quality assessment, sensitivity analysis and heterogeneity were performed. Results In our review, 13 controlled trials met the inclusion criteria. The meta-analysis indicated that the depressive symptoms and depression of nursing students in the intervention groups showed significantly moderate improvements compared with the control groups. Three subgroup analyses showed that mindfulness interventions and stress management programs were common and effective, short-term interventions were beneficial to depression, nonpharmacological interventions had great improvements for Asian nursing students and more rigorous researches on methodological quality are recommended. Conclusion Nonpharmacological interventions can serve as promising complementary and alternative approaches in reducing the depressive symptoms and depression of nursing students. Highlights • Nonpharmacological interventions had moderate positive effects on depressive symptoms and depression. • Mindfulness interventions and stress management programs were common and effective at improving depression. • A short-term (1-8 weeks) intervention length is recommended. • Nonpharmacological interventions have greater improvements for nursing students in Asia. • Nonpharmacological interventions can serve as promising complementary and alternative approaches in reducing depression. [ABSTRACT FROM AUTHOR]

• S. alterniflora invasion altered DOM chemical composition and humification level. • DOM in early-invaded soils was more easily utilized by microorganisms. • Increased importance of DOM composition in shaping microbial community under invasion. • S. alterniflora invasion promoted DOC accumulation mediated by microbial community. Exotic plant invasion dramatically alters soil carbon transformation and shapes the structure and diversity of the microbial community in coastal wetlands. However, it remains unclear how the dissolved organic matter (DOM) optical components and chemical composition and their linkages with soil microorganisms change with increasing time since invasion. Here, we explored the impacts of Spartina alterniflora (S. alterniflora) invasion on DOM compositions and relationships with microbial communities along a short-term chronosequence (i.e., 3-, 5-,10-, and 15-year) in the Yellow River Delta. The results showed an increase in the soil water content, soil organic carbon, dissolved organic carbon, and C/N ratio along the invasion chronosequence, whereas bulk density showed the opposite trend. Moreover, invaded wetland soils had a higher abundance of total phospholipid fatty acids, gram-positive bacteria (G +), gram-negative bacteria (G-), and fungi than tidal flat soils. The DOM in invaded wetland soils was mainly composed of endogenous protein-like components, and the proportion of autochthonous DOM increased over invasion time. The DOM was characterized by low molecular weight, low aromatic content, and low hydrophobic compounds in S. alterniflora wetland soils, whereas in tidal flat soils, the humification degree and DOM molecular weight were higher. The soil microbial communities exhibited stronger linkages with various environmental variables and DOM fluorescence components in invaded wetlands based on redundancy analysis (RDA) and correlation analysis using Mantel tests. Structural Equation Model (SEM) revealed that the soil microbial abundance and community structure induced by increasing S. alterniflora invasion time were the most important drivers of DOM content and chemical composition. The findings of this work provide a better understanding of labile carbon pool turnover in coastal wetlands invaded by S. alterniflora. [ABSTRACT FROM AUTHOR]

• An immersed tunnel is instrumented using distributed optical fiber sensors. • Observed variations in joint opening are strongly correlated with seasonal temperature change. • Observed joint differential settlement has a smaller scale than opening but still shows seasonal variation. • Seasonal joint deformation affects the structure's watertightness performance. Seasonal joint deformations within an immersed tunnel are important indicators to assess structural behavior and therefore should be monitored in detail. In this study, distributed optical fiber sensors (DOFS) are applied to precisely measure the seasonal joint deformations in an immersed tunnel for the first time. Measurements over a one-year period specifically reveal the impact of seasonal temperature variations on the joint opening and uneven settlement deformation. Field monitoring shows that the variation in joint opening exhibits a cyclic behavior and is strongly correlated with temperature change. The immersion joints generally show a larger range of seasonal opening (with a maximum of about 6 mm) than dilation joints, but at several dilation joints significant opening also occurs. The uneven or differential settlement at most joints stays below 1 mm, except at a few joints where the range is above 1 mm, which are indications of underlying structural defects in the tunnel. The observed joint uneven settlement also shows a seasonal variation, but the correlation with temperature is weak. The impacts of seasonal deformation on the structural integrity and watertightness of the tunnel are assessed, and further suggestions on tunnel maintenance and inspection are made. [ABSTRACT FROM AUTHOR]

• Distributed optical fiber sensors are used to monitor immersed tunnel joints. • The sensor layout allows for both joint opening and uneven settlements to be measured. • The transfer relation between measured fiber strain and joint displacements is derived. • An in-lab joint model is used to verify the sub-millimeter accuracy of the sensor. Monitoring the deformations of immersed tunnels is important during the entire tunnel service life to assess the structural integrity of the tunnel. Conventional joint deformation monitoring is based on manual levelling measurements and normally occurs only at multi-year intervals, which does not allow to capture short term deformation behavior. In this study a new joint monitoring system using distributed optical fiber sensors (DOFS) is developed. A special sensor layout is designed that allows simultaneous measurements of both horizontal joint opening and vertical uneven settlement of the immersion and dilation joints. For this sensor scheme the transfer relation from fiber strain to joint deformation is derived and verified by in-lab experiments. The sensor system proves to be able to detect sub-millimeter joint deformations, indicating a more than sufficient accuracy for structural monitoring of immersed tunnel joints. Subsequently, the First Heinenoordtunnel in the Netherlands is instrumented using this distributed optical fiber sensing system, in order to obtain additional data for both long-term and short-term assessment of its structural condition. [ABSTRACT FROM AUTHOR]

• Selection metrics: maximum work strain, limit strain, relaxation, axial stiffness. • Metrics can be calibrated on tension machine or proposed manual tension platform. • Fiber relaxation in tension consists of plastic component and elastic component. • Characteristic loop can be used to interpret fiber relaxation behavior. • The linear relaxation model can quantify the upper bound of measurement error. Distributed optical fiber sensors (DOFS) allow for distributed strain sensing and can be installed to function as extensometers for measuring point-displacements. This paper discusses the metrics of optimal sensing fiber selection for point-displacement measuring. Key metrics include the physical structure, mechanical parameters and light transmission coefficients. Calibration tests for verification of the optical fiber properties are designed and results of four fiber types are presented. Finally, creep and relaxation behavior of optical fibers is discussed based on manual tension test results, and a quantification model is proposed to assess the induced measurement error for sensing fiber. The maximum (absolute) measurement error for two common fiber types used in point displacement measurements is determined to be below 8%, and the study shows that pretensioning of the fiber helps to reduce such measurement errors. [ABSTRACT FROM AUTHOR]

Highlights: [•] Techno-economical and social analysis of energy storage is conducted for commercial buildings. [•] Methodologies for demand analysis, technical, economical and social evaluations are developed. [•] An illustrative example is analyzed for three kinds of energy storage systems. [Copyright &y& Elsevier]

Abstract: Combinations of calcium phosphate scaffolds and bioactive factors are promising niche-mimetic solutions for repairing large-sized bone defects. However, the importance of compatibility between scaffolds and bioactive factors on their osteogenic outcomes has been largely ignored. This study aimed to investigate the compatibility of calcinated antler cancellous bone (CACB) scaffolds with various bioactive factors including icariin (ICA), velvet antler polypeptides (VAP) or recombinant human bone morphogenetic protein-2 (rhBMP-2) as well as their combinational osteogenic potential in vitro and in vivo. Scanning electron microscopy and fourier transform infrared spectroscopy confirmed the uniform distribution and chemical stability of the reagents on CABC. In vitro release profiles showed relative steady release of ICA from ICA/CACB, burst VAP release from VAP/CACB, and minimal rhBMP-2 release from rhBMP-2/CACB composites. When compared with VAP and rhBMP-2, incorporation of ICA within CACB resulted in most increased cell attachment, proliferation, alkaline phosphatase activity, osteogenic gene expression, and mineralization of rat bone marrow mesenchymal stem cells. In rabbit mandible critical-sized defects, the most extensive osteogenesis and neovascularization were observed in the ICA/CACB group. Differences between the VAP/CACB and rhBMP-2/CACB groups were not apparent. Interestingly, low pro-inflammatory (TNF-α, IL-6) and high anti-inflammatory (IL-10) mRNA levels were observed at scaffold implantation sites which were in close association with amount of new bone formation. These findings highlight that the compatibility between scaffolds and bioactive factors should been taken into account when considering the formula of optimized bone defect repair. [Copyright &y& Elsevier]