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Spinal cord injury (SCI) is a severe disease of the nervous system that causes irreparable damage and loss of function, for which no effective treatments are available to date. Engineered extracellular vesicles (EVs) carrying therapeutic molecules hold promise as an alternative SCI therapy depending on the specific functionalized EVs and the appropriate engineering strategy. In this study, we demonstrated the design of a drug delivery system of peptide CAQK-modified, siRNA-loaded EVs (C-EVs-siRNA) for SCI-targeted therapy. The peptide CAQK was anchored through a chemical modification to the membranes of EVs isolated from induced neural stem cells (iNSCs). CCL2-siRNA was then loaded into the EVs through electroporation. The modified EVs still maintained the basic properties of EVs and showed favorable targeting and therapeutic effects

RNA N6-methyladenosine (m6A) modification is involved in diverse biological processes. However, its role in spinal cord injury (SCI) is poorly understood. The m6A level increases in injured spinal cord, and METTL3, which is the core subunit of methyltransferase complex, is upregulated in reactive astrocytes and further stabilized by the USP1/UAF1 complex after SCI. The USP1/UAF1 complex specifically binds to and subsequently removes K48-linked ubiquitination of the METTL3 protein to maintain its stability after SCI. Moreover, conditional knockout of astrocytic METTL3 in both sexes of mice significantly suppressed reactive astrogliosis after SCI, thus resulting in widespread infiltration of inflammatory cells, aggravated neuronal loss, hampered axonal regeneration, and impaired functional recovery. Mechanistically, theYAP1transcript was identified as a potential target of METTL3 in astrocytes. METTL3 could selectively methylate the 3′-UTR region of theYAP1transcript, which subsequently maintains its stability in an IGF2BP2-dependent manner.In vivo, YAP1 overexpression by adeno-associated virus injection remarkably contributed to reactive astrogliosis and partly reversed the detrimental effects of METTL3 knockout on functional recovery after SCI. Furthermore, we found that the methyltransferase activity of METTL3 plays an essential role in reactive astrogliosis and motor repair, whereas METTL3 mutant without methyltransferase function failed to promote functional recovery after SCI. Our study reveals the previously unreported role of METTL3-mediated m6A modification in SCI and might provide a potential therapy for SCI.SIGNIFICANCE STATEMENTSpinal cord injury is a devastating trauma of the CNS involving motor and sensory impairments. However, epigenetic modification in spinal cord injury is still unclear. Here, we propose an m6A regulation effect of astrocytic METTL3 following spinal cord injury, and we further characterize its underlying mechanism, which might provide promising strategies for spinal cord injury treatment.

The purpose of the current study was to explore radiographic predictors for recurrence of lumbar symptoms after prioritized cervical surgery in patients with tandem spinal stenosis (TSS).The current retrospective cohort study included 74 patients with TSS, who underwent prioritized cervical surgery. Based on presence or absence of improvement in lower limb symptoms, patients were grouped into improved and non-improved groups. Medical records and radiological parameters including age, sex, body mass index, cervical and lumbar parameters were analyzed. In improved group, patients were divided into relapsed and non-relapsed groups based on recurrence in lower limb symptoms.Lumbar symptoms improved in 70.1% (n = 52) of patients. Comparison between the improved and non-improved group showed that there were no statistically significant differences in cervical parameters while comparisons between the relapsed and non-relapsed groups showed significant differences in redundant nerve roots (RNRs) (p = 0.029), narrow segment (p = 0.042) and lumbar stenosis index (LSI) (p = 0.003). In multivariate logistic regression analysis, LSI 10 (p = 0.016) was independently associated with recurrence of lumbar symptoms.Finding of the current study indicated that LSI 10 was associated with recurrence of lumbar symptoms in TSS patients following cervical surgery.

Study Design: Retrospective Cohort StudyOBJECTIVE We conducted a retrospective study to evaluate the correlation of lumbar compression fractures (LCF) and lumbar spinal stenosis (LSS) ,and to explore the clinical outcomes of different surgical methods.METHODS A total of 134 eligible patients were divided into minor/moderate stenosis and severe/extreme stenosis groups .We counted the patients' age, sex, BMI, BMD, history of hypertension, diabetes, rheumatism and hormone used, symptom duration and history of trauma. The LLA, PI, lumbar spondylolisthesis, LSI(lumbar stenosis indexes) and fracture grades were calculated. The preoperative VAS, ODI and JOA scores of the patients were surveyed, and the clinical outcomes were followed up by telephone.RESULTS There is a clear correlation between the degree of LSS and the degree of fracture(r = 0.532,P CONCLUSIONS There is a clear correlation between LCF and LSS. For patients with severe LCF, it is necessary to perform relevant imaging examinations and pay attention to whether LSS is combined, especially for patients with trauma, obesity or low PI. If the patient has lower extremity symptoms, decompression surgery can be considered if the patient's general condition permits.

Mimicking the natural photosynthesis process to convert carbon dioxide into value-added chemicals is vital to solving both the climate crisis worldwide and the depletion of fossil fuels. Herein, we explore the synthesis of 2D FAPbBr3 nanoplate combined with 2D Ti3C2 nanosheet to form a 2D/2D FAPbBr3/Ti3C2 Schottky heterojunction using facile hot-injection and in-situ growth approaches. The Schottky heterojunction of FAPbBr3/Ti3C2 over large interfacial contact provides abundant channels for transferring photogenerated carriers from FAPbBr3 nanoplate to Ti3C2 nanosheet. The experimental results showed a CO yield of 93.82 μmol·g−1·h−1 with ethyl acetate/deionization water as a sacrificial reagent for FAPbBr3/Ti3C2 composite, which was 1.25-fold enhancement that on pristine FAPbBr3 nanoplates. The large 2D heterointerface can efficiently accelerate the spatial separation and transfer of photogenerated carriers and result in the superior photocatalytic activity and favorable stability of FAPbBr3/Ti3C2 photocatalysts, which are proved by in-situ X-ray photoelectron spectroscopy, photoluminescence, transient absorption spectra, and Mott-Schottky measurement. Thus, this work unveils that 2D/2D Schottky heterostructures would significantly improve the reaction activities of halide perovskite-based photocatalysts.

The improvement of electrochemical performance of lithium-ion (Li-ion) batteries requires in-depth understanding on the structural evolution of electrodes during electrochemical cycling. By taking advantages of sensitive, penetrative and nondestructive properties of neutrons, we adopted in operando neutron diffraction technique to explore structural characteristics of electrodes in LiNi0.5Co0.2Mn0.3O2/Graphite full cell during cycling in real time. It is revealed that the concentration of Li/Ni antisite defects varies and presents regular volcano shape in layered cathode during cycling due to the competition effect between delithiation and magnetic frustration. Moreover, visualization of the Li-ion migration pathway in cathode by maximum entropy method indicates that lithium ions diffuse via tetrahedral site hopping path at the initial state of charge, but a newly-discovered indirect zigzag hopping path dominates afterwards. As for graphite anode counterpart, the intercalation of lithium ions into anode undergoes few distinct stages, including the formation of an intermediate phase with lithium gradient. All these observations concerning the simultaneous structural variation of both cathode and anode unveil the underlying migration behavior of lithium ions in NCM/Graphite full cell and enlighten us to devise an optimized pathway for Li-ion migration toward achieving high-performance Li-ion batteries.

Novel BaTiO3/Ti3C2Tx piezo-photocatalysts are fabricated via an in-situ solvothermal method. The synergistic effect of BaTiO3 and Ti3C2Tx increases piezo-photocatalytic activity.

Spinal cord injury (SCI) can result in irreversible sensory and motor disability with no effective treatment currently. After SCI, infiltrated macrophages accumulate in epicenter through destructed blood-spinal cord barrier (BSCB). Further, great majority of macrophages are preferentially polarized to M1 phenotype, with only a few transient M2 phenotype. The purpose of this study was to explore roles of vascular endothelial cells in microglia/macrophages polarization and the underlying mechanism. Lipopolysaccharide (LPS) was used to pretreat BV2 microglia and RAW264.7 macrophages followed by administration of conditioned medium from microvascular endothelial cell line bEnd.3 cells (ECM). Analyses were then performed to determine the effects of exosomes on microglia/macrophages polarization and mitochondrial function. The findings demonstrated that administration of ECM shifted microglia/macrophages towards M2 polarization, ameliorated mitochondrial impairment, and reduced reactive oxygen species (ROS) production in vitro. Notably, administration of GW4869, an exosomal secretion inhibitor, significantly reversed these observed benefits. Further results revealed that exosomes derived from bEnd.3 cells (Exos) promote motor rehabilitation and M2 polarization of microglia/macrophages in vivo. Ubiquitin-specific protease 13 (USP13) was shown to be significantly enriched in BV2 microglia treated with Exos. USP13 binds to, deubiquitinates and stabilizes the NF-κB inhibitor alpha (IκBα), thus regulating microglia/macrophages polarization. Administration of the selective IκBα inhibitor betulinic acid (BA) inhibited the beneficial effect of Exos in vivo. These findings uncovered the potential mechanism underlying the communications between vascular endothelial cells and microglia/macrophages after SCI. In addition, this study indicates exosomes might be a promising therapeutic strategy for SCI treatment.

Spinal cord ischemia-reperfusion injury (SCIRI) is a serious trauma that can lead to loss of sensory and motor function. Ferroptosis is a new form of regulatory cell death characterized by iron-dependent accumulation of lipid peroxides. Ferroptosis has been studied in various diseases; however, the exact function and molecular mechanism of ferroptosis in SCIRI remain unknown. In this study, we demonstrated that ferroptosis is involved in the pathological mechanism of SCIRI. Inhibition of ferroptosis could promote the recovery of motor function in mice after SCIRI. In addition, we found that ubiquitin-specific protease 11 (USP11) was significantly upregulated in neuronal cells after hypoxia-reoxygenation and in the spinal cord in mice with I/R injury. Knockdown of USP11 in vitro and KO of USP11 in vivo (USP11(−/Y)) significantly decreased neuronal cell ferroptosis. In mice, this promotes functional recovery after SCIRI. In contrast, in vitro, USP11 overexpression leads to classic ferroptosis events. Overexpression of USP11 in mice resulted in increased ferroptosis and poor functional recovery after SCIRI. Interestingly, upregulating the expression of USP11 also appeared to increase the production of autophagosomes and to cause substantial autophagic flux, a potential mechanism through which USP11 may enhance ferroptosis. The decreased autophagy markedly weakened the ferroptosis mediated by USP11 and autophagy induction had a synergistic effect with USP11. Importantly, USP11 promotes autophagy activation by stabilizing Beclin 1, thereby leading to ferroptosis. In conclusion, this study shows that ferroptosis is closely associated with SCIRI, and that USP11 plays a key role in regulating ferroptosis and additionally identifies USP11-mediated autophagy-dependent ferroptosis as a promising target for the treatment of SCIRI.

Objective An increasing number of circular RNAs (circRNAs) have been identified as emerging competing endogenous RNAs (ceRNAs) that play important roles in hepatocellular carcinoma (HCC), but numerous circRNAs remain unexplored. The aim of this study was to explore the mechanism of action of differentially expressed circRNAs and their ceRNA networks in HCC. Methods Second-generation sequencing technology was used to analyse the expression of circRNAs in cancerous and paired paraneoplastic tissues from five patients with HCC. The circRNAs with a P value of less than 0.01, with an original signal value greater than 100 and ranked among the top ten upregulated circRNAs were selected and validated by quantitative reverse transcription polymerase chain reaction (qRT‒PCR) in paired cancer and paraneoplastic tissues from another 34 HCC patients. The downstream miRNAs and mRNAs of the circRNAs were explored through database analysis, and finally, the ceRNA networks and circRNA–miRNA–mRNA axes based on these ten circRNAs were constructed. Results By sequencing, we identified 9658 differentially expressed circRNAs on all chromosomes, of which 3862 were significantly upregulated and 5796 were significantly downregulated. RT-qPCR was performed to validate the top ten upregulated circRNAs, and the results were generally consistent with the sequencing results. After qRT‒PCR validation, five circRNAs (hsa_circ_0079875, hsa_circ0091580, hsa_circ0091581, hsa_circ0004788 and hsa_circ_0059730) were selected for further analysis. First, the downstream miRNAs and mRNAs of these five circRNAs were predicted to construct circRNA-miRNA‒mRNA network diagrams. The 1482 upregulated mRNAs identified in the GEPIA database overlapped with the 278 mRNAs in the ceRNA networks, and 14 overlapping genes were identified. Further bioinformatics analysis revealed four mRNAs (ADSL, AP3B1, MAPRE1, and TRNP1) and five circRNA–miRNA–mRNA axes that were negatively correlated with HCC prognosis. Conclusions Numerous differentially expressed circRNAs exist in HCC, and most can regulate the biological behaviour of HCC through circRNA-miRNA‒mRNA networks. Bioinformatics analysis showed that the ceRNA regulatory axes in HCC have high diagnostic and prognostic value and deserve further exploration. This study aims to provide new research ideas related to HCC pathogenesis and treatment options.

Increasing temperature is proposed to improve the performance of Rotational Supercavitating Evaporator (RSCE, a novel supercavitation-based desalination device). In order to investigate the temperature effect on the hydrodynamic characteristics of RSCE, visualization experiments are conducted on cavitating flows at different water temperatures (25–50 °C) in RSCE under different rotational speeds (up to 4000 r/min). Then the thermodynamic effect of cavitation in the water at different temperatures is evaluated to obtain the temperature range suitable for the operation of RSCE. Results show that the spatiotemporal evolutions of cavitation at different water temperatures are similar and the cavitation intensity increases with increasing temperature. Combining the present experimental results with revisits to the published results, four criteria are put forward to evaluate the thermodynamic effect of cavitation, including the variation of dimensionless supercavity length with cavitation number, the variation of incipient cavitation number with temperature, the appearance of cavitation, and the threshold value of thermodynamic parameter Σ of order hundred. It can be deduced by these criteria that the thermodynamic effect of cavitation in the water is insignificant within the temperature range considered in the present work. Hence, the desalination performance of RSCE can be improved by increasing temperature within above temperature range.

BackgroundThe mortality rate in patients with ankylosing spondylitis (AS) and cervical fracture is relatively high.ObjectivesThis study aimed to investigate the instantaneous death risk and conditional survival (CS) in patients with AS and cervical fracture. We also studied the relationship between surgical timing and the incidence of complications.MethodsThis national multicentre retrospective study included 459 patients with AS and cervical fractures between 2003 and 2019. The hazard function was used to determine the risk of instantaneous death. The five-year CS was calculated to show the dynamic changes in prognosis.ResultsThe instantaneous death risk was relatively high in the first 6 months and gradually decreased over time in patients with AS and cervical fracture. For patients who did not undergo surgery, the instantaneous risk of death was relatively high in the first 15 months and gradually decreased over time. For patients with American Spinal Injury Association impairment scale (ASIA) A and B, the 5-year CS was 55.3% at baseline, and improved steadily to 88.4% at 2 years. Odds ratios (ORs) for pneumonia, electrolyte disturbance, respiratory insufficiency, and phlebothrombosis decreased as the surgery timing increased.ConclusionDeaths occurred mainly in the first 6 months after injury and gradually decreased over time. Our study highlights the need for continued surveillance and care in patients with AS with cervical fractures and provides useful survival estimates for both surgeons and patients. We also observed that early surgery can significantly increase functional recovery, and decrease the incidence of complications and rehospitalisation.

The encoding of noxious stimuli into action potential firing is largely mediated by nociceptive free nerve endings. Tissue inflammation, by changing the intrinsic properties of the nociceptive endings, leads to nociceptive hyperexcitability and thus to the development of inflammatory pain. Here, we showed that tissue inflammation-induced activation of the mammalian target of rapamycin complex 2 (mTORC2) triggers changes in the architecture of nociceptive terminals and leads to inflammatory pain. Pharmacological activation of mTORC2 induced elongation and branching of nociceptor peripheral endings and caused long-lasting pain hypersensitivity. Conversely, nociceptor-specific deletion of the mTORC2 regulatory protein rapamycin-insensitive companion of mTOR (Rictor) prevented inflammation-induced elongation and branching of cutaneous nociceptive fibers and attenuated inflammatory pain hypersensitivity. Computational modeling demonstrated that mTORC2-mediated structural changes in the nociceptive terminal tree are sufficient to increase the excitability of nociceptors. Targeting mTORC2 using a single injection of antisense oligonucleotide against Rictor provided long-lasting alleviation of inflammatory pain hypersensitivity. Collectively, we showed that tissue inflammation-induced activation of mTORC2 causes structural plasticity of nociceptive free nerve endings in the epidermis and inflammatory hyperalgesia, representing a therapeutic target for inflammatory pain.

Background Spinal cord ischemia reperfusion injury (SCIRI) is a complication of aortic aneurysm repair or spinal cord surgery that is associated with permanent neurological deficits. Mesenchymal stem cell (MSC)-derived small extracellular vesicles (sEVs) have been shown to be potential therapeutic options for improving motor functions after SCIRI. Due to their easy access and multi-directional differentiation potential, adipose‐derived stem cells (ADSCs) are preferable for this application. However, the effects of ADSC-derived sEVs (ADSC-sEVs) on SCIRI have not been reported. Results We found that ADSC-sEVs inhibited SCIRI-induced neuronal apoptosis, degradation of tight junction proteins and suppressed endoplasmic reticulum (ER) stress. However, in the presence of the ER stress inducer, tunicamycin, its anti-apoptotic and blood–spinal cord barrier (BSCB) protective effects were significantly reversed. We found that ADSC-sEVs contain tumor necrosis factor (TNF)-stimulated gene-6 (TSG-6) whose overexpression inhibited ER stress in vivo by modulating the PI3K/AKT pathway. Conclusions ADSC-sEVs inhibit neuronal apoptosis and BSCB disruption in SCIRI by transmitting TSG-6, which suppresses ER stress by modulating the PI3K/AKT pathway.

The existing reflector not requiring solar tracking used in solar flat-plate collector is mainly plate-type structure. This kind of structure is simple, but it is not the optimal one. To solve this problem, the new polyline-type and parabolic-type reflectors not requiring solar tracking were proposed for solar flat-plate collectors in this paper. A comparative study of the two types of reflectors and the existing plate-type reflectors under no sun-tracking conditions was carried out by theoretical and experimental methods. The reflected light losses under the off-design conditions were analyzed. The transient and annual operation characteristics were discussed. The results showed that under the design conditions the ranking of boost factor is parabolic-type, polyline-type and plate-type. But the reflection losses under the off-design conditions are just the opposite. Under the same reflective area with the collectors, when the reflection losses are considered, the increases of solar radiation on the collectors are 40.3%, 27.7% and 19.8% for the polyline, parabolic and flat-plate reflectors respectively in the heating season. In the coldest three months, the polyline-type always has the largest solar radiation. This paper is helpful to improve the efficiency and economy of solar space heating in cold areas.

Reactive astrogliosis is a pathological feature of spinal cord injury (SCI). The ubiquitin-proteasome system plays a crucial role in maintaining protein homeostasis and has been widely studied in neuroscience. Little, however, is known about the underlying function of deubiquitinating enzymes in reactive astrogliosis following SCI. Here, we found that ubiquitin-specific protease 18 (USP18) was significantly upregulated in astrocytes following scratch injury, and in the injured spinal cord in mice. Knockdown of USP18 in vitro and conditional knockout of USP18 in astrocytes (USP18 CKO) in vivo significantly attenuated reactive astrogliosis. In mice, this led to widespread inflammation and poor functional recovery following SCI. In contrast, overexpression of USP18 in mice injected with adeno-associated virus (AAV)-USP18 had beneficial effects following SCI. We showed that USP18 binds, deubiquitinates, and thus, stabilizes SRY-box transcription factor 9 (SOX9), thereby regulating reactive astrogliosis. We also showed that the Hedgehog (Hh) signaling pathway induces expression of USP18 through Gli2-mediated transcriptional activation after SCI. Administration of the Hh pathway activator SAG significantly increased reactive astrogliosis, reduced lesion area and promoted functional recovery in mice following SCI. Our results demonstrate that USP18 positively regulates reactive astrogliosis by stabilizing SOX9 and identify USP18 as a promising target for the treatment of SCI.

Osteoarthritis (OA) is a regressive joint disease that mainly affects the cartilage and surrounding tissues. Mounting studies have confirmed that the paracrine effect is related to the potential mechanism of mesenchymal stem cell (MSC) transplantation and that small extracellular vesicles (sEVs) play an imperative role in this paracrine signaling. In fact, hypoxia can significantly improve the effectiveness of MSC transplantation in various disease models. However, it remains unknown whether MSCs in the state of a hypoxic environment can enhance OA cartilage repair and whether this enhancement is mediated by sEV signaling. The primary aim of the present study was to determine whether sEVs from MSCs in the state of hypoxia (Hypo-sEVs) have a superior effect on OA cartilage repair relative to sEVs from MSCs in the normoxia (Nor-sEVs) state. By using an OA model and performing in vitro studies, we verified that Hypo-sEV treatment facilitated the proliferation, migration, and apoptosis suppression of chondrocytes to a greater extent than Nor-sEV treatment. Furthermore, we verified the functional role of sEV miR-216a-5p in the OA cartilage repair process. We also identified JAK2 as the target gene of sEV miR-216a-5p through a series of experiments. Our findings indicated that HIF-1α induces hypoxic BMSCs to release sEVs, which promote the proliferation, migration, and apoptosis inhibition of chondrocytes through the miR-216a-5p/JAK2/STAT3 signaling pathway. Therefore, hypoxic pretreatment is a prospective and effective method to maximize the therapeutic effect of MSC-derived sEVs on OA.

There has been a remarkably increasing interest in applying acoustofluidics in micro-electro-mechanical systems and lab-on-a-chip systems in the past decades. This paper investigated the heat trans...

Metal halide perovskite with a suitable energy band structure and excellent visible-light response is a prospective photocatalyst for CO2 reduction. However, the reported inorganic halide perovskites have undesirable catalytic performances due to phase-sensitive and severe charge carrier recombination. Herein, we anchor the FAPbBr3 quantum dots (QDs) on Ti3C2 nanosheets to form a FAPbBr3/Ti3C2 composite within a Schottky heterojunction for photocatalytic CO2 reduction. Upon visible-light illumination, the FAPbBr3/Ti3C2 composite photocatalyst exhibits an appealing photocatalytic performance in the presence of deionized water. The Ti3C2 nanosheet acts as an electron acceptor to promote the rapid separation of excitons and supply specific catalytic sites. An optimal electron consumption rate of 717.18 μmol/g·h is obtained by the FAPbBr3/0.2-Ti3C2 composite, which has a 2.08-fold improvement over the pristine FAPbBr3 QDs (343.90 μmol/g·h). Meanwhile, the FAPbBr3/Ti3C2 photocatalyst also displays a superior stability during photocatalytic reaction. This work expands a new insight and platform for designing superb perovskite/MXene-based photocatalysts for CO2 reduction.

This study aims to assess the nerve function deficient recovery in surgically treated patients with cervical trauma with spinal cord injury (SCI) in chronic stage and figure out prognostic predictors of improvement in impairment and function. We reviewed the clinical and radiological data of 143 cervical SCI patients in chronic stage and divided into non-operative group (n = 61) and operative group (n = 82). The severity of neurological involvement was assessed using the ASIA motor score (AMS) and Functional Independence Measure Motor Score (FIM MS). The health-related quality of life was measured using the SF-36 questionnaire. Correspondence between the clinical and radiological findings and the neurological outcome was investigated. At 2-year follow-up, surgery resulted in greater improvement in AMS and FIM MS than non-operative group. Regression analysis revealed that lower initial AMS (P = 0.000), longer duration after injury (P = 0.022) and injury above C4 level (P = 0.022) were factors predictive of lower final AMS. Longer duration (P = 0.020) and injury above C4 level (P = 0.010) were associated with a lower FIM MS. SF-36 scores were significantly lower in higher age (P = 0.015), female patients (P = 0.009) and patients with longer duration (P = 0.001). It is reasonable to consider surgical decompression in patients with cervical SCI in chronic stage and persistent spinal cord compression and/or gross cervical instability. Initial AMS, longer duration, injury above C4 level, higher age and female patients are the five major relevant factors of functional recovery.

Studies of photocatalytic conversion of CO2 into hydrocarbon fuels, as a promising solution to alleviate global warming and energy issues, are booming in recent years. Researchers have focused their interest in developing g-C3N4 composite photocatalysts with intriguing features of robust light harvesting ability, excellent catalysis, and stable performance. Four types of heterojunctions (type-II, Z-scheme, S-scheme and Schottky) of the g-C3N4 composites are widely adopted. This review aims at presenting and comparing the photocatalytic mechanisms, characteristics, and performances of g-C3N4 composites concerning these four types of heterojunctions. Besides, perspectives and undergoing efforts for further development of g-C3N4 composite photocatalysts are discussed. This review would be helpful for researchers to gain a comprehensive understanding of the progress and future development trends of g-C3N4 composite heterojunctions for photocatalytic CO2 reduction.

Activation of microglia in the spinal cord dorsal horn after peripheral nerve injury contributes to the development of pain hypersensitivity. How activated microglia selectively enhance the activity of spinal nociceptive circuits is not well understood. We discovered that after peripheral nerve injury, microglia degrade extracellular matrix structures, perineuronal nets (PNNs), in lamina I of the spinal cord dorsal horn. Lamina I PNNs selectively enwrap spinoparabrachial projection neurons, which integrate nociceptive information in the spinal cord and convey it to supraspinal brain regions to induce pain sensation. Degradation of PNNs by microglia enhances the activity of projection neurons and induces pain-related behaviors. Thus, nerve injury–induced degradation of PNNs is a mechanism by which microglia selectively augment the output of spinal nociceptive circuits and cause pain hypersensitivity.

Owing to an inconsistent load demand, hydraulic turbines are often operated under off-load range. Resultant flow instabilities comprise low-frequency pressure fluctuations, which are dependent on the operating condition and unavoidable high-frequency fluctuations evolving from the interactional design concept of hydrofoils. Through the analysis of averaged flow parameters within the runner, this article investigates the mechanism of reciprocity in flow instabilities between draft tube and upstream components. Two recommended operating conditions are used to approximate harmless traveling disturbances, and two part-load discharges are discussed accordingly. The CFD commercial code ANSYS CFX has been used for unsteady flow simulation, where the Shear Stress Transport (SST) turbulence model has been adopted. The used numerical scheme has been validated through experiments in terms of pressure pulsation characteristics, and findings display a good agreement. It has been found that low-frequency disturbances, as instabilities taking source from the fluid structure itself, can override strong flow gradients and exert a higher backward influence farther than high-frequency perturbations. The low-frequency component and its harmonic strengthened by the wall impact feedback are less sensitive to the backward damping. The blade passing frequency dominates the draft tube inlet to influence the local pressure recovery; but it is rapidly diffused and tapped by the low-frequency core instability.

Reversible pump turbine (RPT)’s runner inter-blade flow unsteadiness onset and development especially under off-design conditions is still one of unresolved issues, yet continues to cause different complications on a daily basis within pumped storage power plants, detrimental pressure pulsations and resulting structural vibrations among others. Though different methods have been used to solve the issue at hand, an adequate solution suitable for all designs has not yet been found; a fact that calls for a more deep understanding in terms of RPT runner flow dynamics and possible influencing parameters. Therefore, the present study seeks to investigate the RPT flow dynamics and associated runner inlet pressure pulsations under off-design operating conditions, as well as the effect of runner blade number on the same. Three RPT models with different runner blade numbers were numerically investigated. The results showed that runner flow unsteadiness has a close relationship with the machine flow conditions, where flow vortices are mostly located at the runner shroud and vicinities. The runner flow unsteadiness decreased with the increasing blade number. The runner blade number considerably influenced runner inlet pressure pulsations where pulsation levels of models with 9 and 10 blades were the highest and lowest respectively.

Hydropower plants provide an asset over other renewables of production flexibility. Away from the turbine design point; detrimental off-load instabilities may compromise the power generation consistency. During part-load operations; the draft tube swirl strongly couples the precessing motion of the vortex rope with the propagation of low-frequency pressure pulsations, further excessive fluid-structure interactions and power swings. To counteract that excitation; different attempts have been devised to dampen local pressure amplitude and detune the instability frequency against the natural system resonance. This article reviews strengths and weaknesses of those remedial attempts applied in the draft tube. They have been categorized as (1) Structural passive methods of shape optimization, J-grooves, stabilizer fins, adjustable diaphragm, baffles, runner cone extension and flow deflectors; (2) Fluidic active techniques of air and water supply and; (3) the hybrid flow control of different approaches. Frequent problems for their optimized effectiveness are: proper dimensions against flow intrusion, vibration and efficiency; location and configuration; performance deterioration of pressure recovery and cavitation; supply conditions of ancillary fluids; hydraulic/head losses; and the activation energy requirement. Future CFD-assisted considerations mainly call for rare hybrid remedy, as no single method can adequately address all instability problems from the draft tube.

This paper discussed the procedure of an optimization design method involving a small lab-scale wind turbine rotor. To simulate the aerodynamic performance of a prototype wind turbine at utility-scale by scaled model experiments (especially, the visualization measurements of wake flow in small wind tunnels), an appropriate similar design of the small lab-scale rotor is needed. However, the similar design of blade performance from a prototype wind turbine for small scaled model is rare. In this paper, using a 2.5 MW utility-scale wind turbine as the prototype, we set up a new optimization process of similar design for a model wind turbine with a 320 mm rotor based on the Lifting-Line Theory (LLT) with wake-induced corrections. Results show a dramatic deviation in performance of the geometric scaled model compared to the objective values, which demonstrates the significance of the Reynolds number effects. With the optimized blade, the distribution of normal thrust force is very similar to the objective values. Geometric characteristics variations along the blade span are similar to the prototype. With the tip speed ratio runs at a roughly matched rated condition, the optimized rotor gives a better performance than other models used in previous wind tunnel studies.

To explore the drag-reducing characteristics of turbulent channel flows with surfactant additive at relatively high Reynolds number from the perspectives of energy spectrum and multi-scale resolution, the two-dimensional fluctuation velocity fields of turbulent channel flows with/without surfactant additive at Reynolds number of Reτ = 590 obtained by large eddy simulation are decomposed by two-dimensional proper orthogonal decomposition (POD) and wavelet transform (WT). POD results show that the low-order eigenmode occupying most energy can be used to capture large-scale vortex structures, and fewer eigenmodes can be employed to capture coherent structures (CSs) in surfactant solution case compared with that in the Newtonian fluid. The spatial structures depicted by POD eigenmode state that buffer layer has a tendency to move towards the center of the channel in surfactant solution. Through wavelet analysis of fluctuation velocity fields in the streamwise-wall-normal planes, it is found that CSs mainly distribute in the near-wall region and the amount of CSs is smaller in surfactant solution. The results of local Reynolds shear measure (LRM) show that local contribution of CSs to the intermittency in turbulent channel flow of surfactant solution decreases, indicating the inhibition of intermittency by surfactant additive. In order to investigate the drag-reducing characteristics at different locations along the wall-normal direction, the fluctuation velocity fields in the streamwise-spanwise planes at different wall-normal locations are decomposed by two-dimensional WT. The results show that surfactant additive mainly affects the flow in the near-wall region (especially in the buffer layer) and thus induces drag reduction effect.

With the continuous development of modern power electronics and chip technology, numerical control inverter power supply is more and more widely used in industrial control and civil fields. High performance numerical control inverter has become one of the research focuses in the power supply field. In this paper, a micro grid simulation system based on single-chip microcomputer is designed. The effective value of the load line current of the inverter part is within 2A, the effective value of the line voltage changes within 24V ± 0.07V, the frequency fluctuation is 50Hz ± 0.2Hz, the total harmonic distortion (THD) of the AC bus voltage is not more than 1.6%, and the power output efficiency reaches 91.6%, achieving good performance. In addition, the system can manually set the power supply output voltage frequency by pressing the key, and display the output voltage and current in real time. At the same time, the system has over-current protection function, which greatly improves the safety and stability when the current is too large.

This study aimed to clarify functional outcomes of facet joint distraction (FJD) and identify specific risk factors for excessive FJD during single-level anterior cervical discectomy and fusion (ACDF) for cervical spondylotic myelopathy (CSM).This study retrospectively analyzed 100 patients who underwent single-level ACDF for CSM from January 2016 to May 2020. Anteroposterior and lateral radiographs were obtained before surgery and 12 months after surgery. Radiographic parameters including anterior intervertebral height (AIH), posterior intervertebral height, facet joint gap, cage posterior depth (CPD), upper vertebral length, cervical segmental Cobb angle (CSCA), C2-C7 Cobb angle, and C2-C7 sagittal vertical axis were analyzed. Functional outcomes were evaluated using the modified Japanese Orthopedic Association Score, visual analog scale (VAS), and Neck Disability Index (NDI).Comparison between the appropriate FJD and excessive FJD groups showed statistically significant differences in the NDI, VAS, CPD, and ΔAIH (P0.05). Multivariate logistic regression analysis showed that independent factors associated with excessive FJD were as follows: a ΔAIH2.28 mm (odds ratio [OR] = 6.792, 95% confidence interval [CI] = 1.885-24.470, P = 0.003), CPD 12.45 mm (OR = 5.876, 95% CI = 1.828-18.895, P = 0.003), and post-CSCA0° (OR = 6.251, 95% CI = 1.275-30.633, P = 0.024). Furthermore, receiver operating characteristic curve analysis for the multilevel logistic regression model produced an area under the curve of 0.783 (P0.001).Patients with an FJD of0.905 mm had worse NDI and VAS pain scores, but not a poorer modified Japanese Orthopedic Association Score recovery rate. Our findings suggested that a ΔAIH2.28 mm, CPD12.45 mm, and post-CSCA0° were independent risk factors for excessive FJD after single-level ACDF for CSM.

Mimicking the natural photosynthesis process to convert carbon dioxide into value-added chemicals is vital to solving both the climate crisis worldwide and the depletion of fossil fuels. Herein, we explore the synthesis of 2D FAPbBr

Spinal cord injury (SCI) is a devastating trauma that leads to irreversible motor and sensory dysfunction and is, so far, without effective treatment. Recently, however, nano-sized extracellular vesicles derived from preconditioned mesenchymal stem cells (MSCs) have shown great promise in treating various diseases, including SCI. In this study, we investigated whether extracellular vesicles (MEVs) derived from MSCs pretreated with melatonin (MT), which is well recognized to be useful in treating diseases, including Alzheimer's disease, non-small cell lung cancer, acute ischemia-reperfusion liver injury, chronic kidney disease, and SCI, are better able to promote functional recovery in mice after SCI than extracellular vesicles derived from MSCs without preconditioning (EVs). MEVs were found to facilitate motor behavioral recovery more than EVs and to increase microglia/macrophages polarization from M1-like to M2-like in mice. Experiments in BV2 microglia and RAW264.7 macrophages confirmed that MEVs facilitate M2-like polarization and also showed that they reduce the production of reactive oxygen species (ROS) and regulate mitochondrial function. Proteomics analysis revealed that ubiquitin-specific protease 29 (USP29) was markedly increased in MEVs, and knockdown of USP29 in MEVs (shUSP29-MEVs) abolished MEVs-mediated benefits in vitro and in vivo. We then showed that USP29 interacts with, deubiquitinates and therefore stabilizes nuclear factor-like 2 (NRF2), thereby regulating microglia/macrophages polarization. In NRF2 knockout mice, MEVs failed to promote functional recovery and M2-like microglia/macrophages polarization. We also showed that MT reduced global N6-methyladenosine (m6 A) modification and levels of the m6 A "writer" methyltransferase-like 3 (METTL3). The stability of USP29 mRNA in MSCs was enhanced by treatment with MT, but inhibited by overexpression of METTL3. This study describes a very promising extracellular vesicle-based approach for treating SCI.

Robot-assisted orthopedic surgery has great application prospects, and the accuracy of the robot is the key to its overall performance. The aim of this study was to develop a new orthopedic surgical robot to assist in spinal surgeries and to compare its feasibility and accuracy with the existing orthopedic robot. A new type of high-precision orthopedic surgical robot (Tuoshou) was developed. A multicenter, randomized controlled trial was carried out to compare the Tuoshou with the TiRobot (TINAVI Medical Technologies Co., Ltd., Beijing) to evaluate the accuracy and safety of their navigation and positioning. A total of 112 patients were randomized, and 108 patients completed the study. The position deviation of the Kirschner wire placement in the Tuoshou group was smaller than that in the TiRobot group (p = 0.014). The Tuoshou group was better than the TiRobot group in terms of the pedicle screw insertion accuracy (p = 0.016) and entry point deviation (p < 0.001). No differences were observed in endpoint deviation (p = 0.170), axial deviation (p = 0.170), sagittal deviation (p = 0.324), and spatial deviation (p = 0.299). There was no difference in security indicators. The new orthopedic surgical robot was highly accurate and optimized for clinical practice, making it suitable for clinical application.