Experimental study on flow characteristics of jet ventilation in crossflow in confined mine spaces.

The increasing depth of mine excavation presents greater challenges in mine ventilation and in managing cooling energy consumption. Therefore, there is an urgent need for comprehensive research on jet ventilation influenced by low-speed crossflows. This study investigated the impact of flow velocity ratios (R) and jet exit diameters (d) on flow-field distribution and flow characteristics through velocity measurements and smoke flow visualization experiments. The results of the study revealed two distinct types of air lakes formed by jet ventilation in crossflow (JVIC), with one being wall-attached and the other suspended. Notably, a significant secondary flow phenomenon was observed in the near-field near the upper wall. Additionally, the deflection angle (θj) of JVIC decreases as R and d/D increase, leading to the formation and movement of a semi-confined point (SP) and a confined point (CP) in the -x direction. Moreover, the wall confinement effect diminishes the jet's diffusion and deflection ability in the -z direction, leading to increased penetration in the x direction. Before the formation of the SP, the deflection section of the jet lengthens, followed by a rapid shortening upon its formation. Finally, the study further developed empirical equations for the jet axial trajectory and diffusion width.

Core-Shell MnFe Nanocatalyst Derived from Prussian Blue Analogs for Peroxymonosulfate Activation: Nonradical Mechanism and Bimetallic Valence Cycle.

Sulfamethazine (SAT) is widely present in sediment, soil, rivers, and groundwater. Unfortunately, traditional water treatment technologies are inefficient at eliminating SAT from contaminated water. Therefore, developing an effective and ecologically friendly treatment procedure to effectively remove SAT is critical. This has raised concerns about its potential impact on the environment and human health. In this study, metal-organic-inorganic composites consisting of graphene-encapsulated Fe-Mn metal catalyst (Mn3Fe1-NC) were synthesized by calcining MnFe Prussian blue analogs (PBA) under a nitrogen atmosphere. The composites were applied to activate peroxymonosulfate (PMS) and facilitate the degradation of SAT in aquatic environments. The Mn3Fe1-NC, dosed with 5 mg, in combination with PMS, dosed with 1.5 mmol L-1, achieved a 91.8% degradation efficiency of SAT. The transformation of the CN skeleton led to the formation of a carbon shell structure, which consequently reduced metal ion leaching from the material. At various pH levels, the iron and manganese ions were observed to leach out at levels lower than 0.1392 and 0.0580 mg L-1, respectively. In contrast, the Mn3Fe1-NC was found to be minimally impacted by pH levels and coexisting ions present in the aqueous environment. Radical burst experiments and electrochemical analysis tests verified that degradation primarily occurs through the nonradical pathway of electron transfer. The active sites responsible for this process were identified as the Mn (IV) and graphitic-N atoms on the material, which facilitate direct electron transfer. Additionally, the presence of Fe atoms promotes the valence cycling of Mn atoms. This study introduces new insights into the reaction mechanism and the constitutive relationship of catalytic centers in nonradical oxidation reactions.

Dynamic evolutionary characteristics and influence mechanisms of carbon emission intensity in counties of the Yangtze River Delta, China.

Clarifying the intrinsic mechanism of county carbon emission intensity (CEI) is essential for guiding the realization of a low-carbon economy as well as for the strategic goals of carbon peaking and carbon neutrality. However, at present, scholars mostly focus on provincial and city scales, with the identification of influencing factors and spatial effect mechanisms of CEI rarely included in the analysis framework. Herein, with the help of three spatial weight matrices, the spatial autocorrelation, the "F + S" influence factor identification method, and the spatial panel econometric model were used to analyze the evolutionary paths and influencing factors of CEI for 209 counties in the Yangtze River Delta (YRD) from 2007 to 2020. The results show that (1) the CEI of the YRD decreased from 1.998t/104 RMB to 0.858t/104 RMB. Furthermore, the spatial pattern was low in the southeast and high in the northwest, with high-value areas concentrated in municipal districts and resource-based counties. (2) Moran's I spatial autocorrelation index indicated significant spatial clustering of county CEI. (3) Financial science and technology expenditure, industrial structure, share of urban built-up land, and the urban-rural income gap affected the change in CEI and its spatial effect, whereas total imports and exports had a significant negative effect on local CEI. Therefore, to achieve China's "double carbon" goal, it is necessary to consider the five development concepts as the core, strengthen inter-county exchanges and collaboration, as well as promote collaborative management of the ecological environment.

Sustained release of naringin from silk-fibroin-nanohydroxyapatite scaffold for the enhancement of bone regeneration.

Bone defects are a common challenge in the clinical setting. Bone tissue engineering (BTE) is an effective treatment for the clinical problem of large bone defects. In this study, we fabricated silk fibroin (SF)/hydroxyapatite (HAp) scaffolds inlaid with naringin poly lactic-co-glycolic acid (PLGA) microspheres, investigating the feasibility of their application in BTE. Naringin PLGA microspheres were manufactured and adhered to the SF/HAp scaffold. Bone mesenchymal stem cells (BMSCs) were inoculated onto the SF/HAp scaffold containing naringin PLGA microsphere to examine the biocompatibility of the SF/HAp scaffolds. A rabbit femoral distal bone defect model was used to evaluate the in vivo function of the SF/HAp scaffolds containing naringin-loaded PLGA microspheres. The current study demonstrated that SF/HAp scaffolds containing naringin-loaded PLGA microspheres show promise as osteo-modulatory biomaterials for bone regeneration.

Naringin-inlaid silk fibroin/hydroxyapatite scaffold enhances human umbilical cord-derived mesenchymal stem cell-based bone regeneration.

OBJECTIVES: Large bone defects are a common, debilitating clinical condition that have substantial global health and economic burden. Bone tissue engineering technology has become one of the most promising approaches for regenerating defective bones. In this study, we fabricated a naringin-inlaid composite silk fibroin/hydroxyapatite (NG/SF/HAp) scaffold to repair bone defects. MATERIALS AND METHODS: The salt-leaching technology was used to fabricate the NG/SF/HAp scaffold. The cytocompatibility of the NG/SF/HAp scaffold was assessed using scanning electron microscopy, live/dead cell staining and phalloidin staining. The osteogenic and angiogenic properties were assessed in vitro and in vivo. RESULTS: The porous NG/SF/HAp scaffold had a well-designed biomimetic porous structure with osteoinductive and angiogenic activities. A gene microarray identified 854 differentially expressed genes between human umbilical cord-derived mesenchymal stem cells (hUCMSCs) cultured on SF-nHAp scaffolds and cells cultured on NG/SF/HAp scaffolds. The underlying osteoblastic mechanism was investigated using hUCMSCs in vitro. Naringin facilitated hUCMSC ingrowth into the SF/HAp scaffold and promoted osteogenic differentiation. The osteogenic and angiogenic capabilities of cells cultured in the NG/SF/HAp scaffold were superior to those of cells cultured in the SF/HAp scaffold. CONCLUSIONS: The data indicate the potential of the SF/HAp composite scaffold incorporating naringin for bone regeneration.

3-photon microscopy of myelin in mouse digital skin excited at the 1700-nm window.

Myelin is a key component of the peripheral nervous system, whose structure anomaly in the digital skin is implicated in neuropathy. Here we demonstrate an in vivo labeling and imaging technique, capable of visualizing myelin sheaths deep in the mouse digital skin. Through material characterization, we verify that 3-photon fluorescence (3PF) can be generated from a commonly used dye- FluoroMyelin Red for labeling myelin, excited at the 1700-nm window. Topical injection of FluoroMyelin Red in the mouse digit leads to bright labeling of myelin sheaths. Harnessing the deep-penetration capability of 3-photon microscopy excited at the 1700-nm window, we demonstrate that 3PF imaging of FluoroMyelin Red-labeled myelin sheaths in the mouse digit in vivo can be achieved to a depth 340 µm below the skin surface, revealing both branching bundle of and individual myelin sheaths.

The efficacy of perioperative gabapentin for the treatment of postoperative pain following total knee and hip arthroplasty: a meta-analysis.

BACKGROUND: Postoperative pain after total knee arthroplasty (TKA) and total hip arthroplasty (THA) influence patients' rehabilitation and life quality. Although gabapentin has been widely used for analgesia, its efficacy is still controversial in TKA and THA. This meta-analysis was performed to assess the efficacy and safety of gabapentin following TKA and THA. METHOD: Electronic databases including PubMed, EMBASE, Cochrane Central Register of Controlled Trials, MEDLINE, and ClinicalTrials.gov were comprehensively retrieved for randomized controlled trials from their inception to June 2019. A total of 7 studies, which compared the administration of gabapentin with that of placebo for the treatment of postoperative pain, were included in our meta-analysis. The meta-analysis was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. RESULT: There was no difference in pain score at 24 (P = 0.87), 48 (P = 0.15), and 72 (P = 0.85) h associated with the use of gabapentin. Likewise, no difference in accumulative morphine consumption at 48 h following TKA or THA was found between gabapentin and placebo (DM = - 8.14, 95% CI - 18.55 to 2.28, P = 0.13). The incidence of opioid-related adverse effects, including nausea, pruritus, sedation, and dizziness, is no difference between gabapentin and placebo group. However, subgroup analysis indicated that gabapentin could reduce the incidence of pruritus after TKA (RR = 0.35, 95% CI 0.12 to 0.99, P = 0.05). CONCLUSION: Based on our meta-analysis, gabapentin did not decrease postoperative pain, cumulative morphine consumption, and the incidence of adverse effects after TKA and THA. There was not enough evidence to support the administrations of gabapentin for postoperative pain after TKA and THA.

Human umbilical cord mesenchymal stem cell-derived exosomes act via the miR-1263/Mob1/Hippo signaling pathway to prevent apoptosis in disuse osteoporosis.

Disuse osteoporosis (DOP) is a common complication resulting from the lack of or disuse of mechanical loading and has been unsatisfactorily treated. We hypothesized that exosomes derived from human umbilical cord mesenchymal stem cells (HUCMSCs) could reduce bone marrow mesenchymal stem cell (BMSC) apoptosis in rat DOP via the miR-1263/Mob1/Hippo signaling pathway. To evaluate the function of exosomes derived from HUCMSCs (HUCMSC-Exos) in DOP, hind limb unloading (HLU)-induced DOP rat models were prepared. In vitro, the proliferation of BMSCs were evaluated using CCK-8 assays. Further, the apoptosis of BMSCs were evaluated using annexin V-FITC assay and Western blots. In vivo, the protective effects of HUCMSC-Exos were evaluated using HE staining and microCT analysis. The underlying molecular mechanism of exosome action on BMSC apoptosis through the miR-1263/Mob1/Hippo pathway was also investigated by high-throughput RNA sequencing, luciferase reporter assays, RNA-pull down assays and Western blots. The RNA-seq and q-PCR results showed that the level of miR-1263 was most abundant among differentially expressed microRNAs. Exosomal miR-1263 could bind to the 3'untranslated region (3' UTR) of Mob1 and exert its function by directly targeting Mob1 in recipient cells. The inhibition of Mob1 could activate YAP expression. Hippo inhibition reversed the in vitro HLU-induced apoptotic effect on BMSCs. The microCT and HE staining results indicated that HUCMSC-Exos ameliorated DOP in vivo. Exosomes derived from HUCMSCs are effective at inhibiting BMSC apoptosis and preventing rat DOP. This mechanism is mediated by the miR-1263/Mob1/Hippo signaling pathway.