Polychromatic photonic Floquet-Bloch oscillations.

Photonic Floquet-Bloch oscillations (FBOs), a new type of Bloch-like oscillations in photonic Floquet lattices, have recently been observed as a typical discrete self-imaging effect. Here, we theoretically investigate the spectral range of approximate photonic Floquet-Bloch oscillations in arrays of evanescently coupled optical waveguides and show the adjustability of the spectral range. At an appropriate amplitude of the Floquet modulation, we have demonstrated approximate photonic FBOs over a broad spectral range, termed "polychromatic photonic Floquet-Bloch oscillations," which manifest as approximate self-imaging of polychromatic beams. Furthermore, by designing the functional form of the Floquet modulation, we can cascade two polychromatic photonic FBOs and further enhance the performance of polychromatic self-imaging. Our results provide a simple and novel mechanism for achieving polychromatic self-imaging in waveguide arrays and may find applications in polychromatic beam shaping and broadband optical signal processing.

[Characteristics and Cause of PM2.5 During Haze Pollution in Winter 2022 in Zhoukou, China].

The characteristics and main factors of causes of haze in Zhoukou in January 2022 were analyzed. Six air pollutants, water-soluble ions, elements, OC, EC, and other parameters in fine particulate matter were monitored and analyzed using a set of online high-time-resolution instruments in an urban area. The results showed that the secondary inorganic aerosols(SNA), carbonaceous aerosols(CA, including organic carbon OC and inorganic carbon EC), and reconstructed crustal materials(CM, such as Al2O3, SiO2, CaO, and Fe2O3, etc.) were the three main components, accounting for 61.3%, 24.3%, and 9.72% in PM2.5, respectively. The concentrations of SNA, CA, CM, and SOA were increased, accompanied with higher AQI. The sulfur oxidation rate(SOR) and nitrogen oxidation rate(NOR) in January were 0.53 and 0.46, respectively. The growth rates[µg·(m3·h)] of sulfate and nitrate were 0.027(-5.89-9.47, range) and 0.051(-23.1-12.4), respectively. During the haze period, the growth rates of sulfate and nitrate were 0.13 µg·(m3·h)-1and 0.24 µg·(m3·h)-1, which were 4.8 and 4.7 times higher than the average value of January, respectively. Although the sulfur oxidation rate was greater than the nitrogen oxidation rate, the growth rate of nitrate was approximately 1.8 times that of sulfate owing to the difference in the concentration of gaseous precursors and the influence of relative humidity. The growth rates of nitrate in SNA were significantly higher than those of sulfate on heavily polluted days. The values of SOR, NOR, and concentrations of SNA and SOA during higher AQI and humidity periods were higher than those in lower AQI and humidity periods. The Ox(NO2+O3) decreased with the increase in relative humidity. The SOA was higher at nighttime, increasing faster with the humidity than that in daytime. Under the situation of lower temperature, higher humidity, and lower wind speed, the emission of gaseous precursors of SNA requires further attention in Zhoukou in winter. Advanced control strategies of emissions of SO2 and NO2, such as mobile sources and coal-burning sources, could reduce the peak of haze in winter efficiently.

[Transport Influence and Potential Sources of PM2.5 Pollution for Nanjing].

In this study, 24-hour backward trajectories of the air mass in Nanjing were calculated by using the HYSPLIT model with the NCEP global reanalysis data from March 2019 to February 2020. The backward trajectories combined with the hourly concentration data of PM2.5 were then utilized in the trajectory clustering analysis and potential pollution source analysis. The results showed that the average concentration of PM2.5 in Nanjing was(36±20) µg·m-3 during the study period, with 17 days exceeding the grade Ⅱ national ambient air quality standards (75 µg·m-3). PM2.5 concentration exhibited clear seasonal variation, with winter (49 µg·m-3)>spring (42 µg·m-3)>autumn (31 µg·m-3)>summer (24 µg·m-3). PM2.5 concentration was significantly positively correlated with surface air pressure but significantly negatively correlated with air temperature, relative humidity, precipitation, and wind speed. Based on the trajectories, seven transport routes were identified in spring, and six routes for the other seasons. The northwest and south-southeast routes in spring, southeast route in autumn, and southwest route in winter were the main pollution transport routes in each season, with the characteristics of short transport distance and slow air mass movement, indicating that local accumulation was one of the main reasons for the high value of PM2.5 in quiet and stable weather. The distance of the northwest route in winter was large, and the PM2.5 concentration was 58 µg·m-3, which was the 2nd highest concentration in all routes, indicating that the cities in the northeast of Anhui had a great transport influence on Nanjing PM2.5. The distribution of PSCF and CWT was relatively consistent, and the main potential source areas were mainly local and adjacent areas of Nanjing, indicating that PM2.5 control is needed to strengthen local control and carry out joint prevention and control with adjacent areas. Winter was most affected by transport, its main potential source area was located at the junction of northwest Nanjing and Chuzhou, and the main source origin was in Chuzhou; therefore joint prevention and control should be expanded to Anhui.

MALAT1 participates in the role of platelet-rich plasma exosomes in promoting wound healing of diabetic foot ulcer.

Exosomes isolated from platelet-rich plasma (PRP-exos) have been recently deemed as an optimized therapeutic strategy in diabetic foot ulcer (DFU) treatment. Herein, we aimed to explore whether MALAT1 participates in DFU wound healing by PRP-exos treatment and the related preliminary mechanism. Fibroblasts were isolated from healthy donors and DFU patients, and the expression of MALAT1, miR-374a-3p and DNMT3A were detected by RT-PCR. The effect of MALAT1 and miR-374a-3p on DFU fibroblast function was verified by gain/loss of function experiment. The targeted binding of MALAT and miRNA was verified by double luciferase reporter gene assay. PRP-exos were isolated from normal human blood and characterized, and then co-cultured with DFU fibroblasts. The MALAT1 expression was donwregulated while the miR-374a-5p expression was upregulated in DFU fibroblasts. Double luciferase reporter gene assay demonstrated the targeted binding of MALAT and miR-374a-5p. Overexpression of MALAT1 or knockdown of miR-374a-5p could increase viability and inhibit apoptosis and pyroptosis of DFU fibroblast. And overexpression of miR-374a-5p reversed the effect of PRR-exos or MALAT1 overexpression on cell viability, apoptosis and pyroptosis. Collectively, MALAT1 mediated signal axis participates in the role of PRP-exos in promoting DFU wound healing, which may help identify optimal targets and effective therapies for DFU treatment.

A biocompatible cell cryoprotectant based on sulfoxide-containing amino acids: mechanism and application.

The preservation of cells at cryogenic temperatures requires the presence of cryoprotectants (CPAs). Dimethyl sulfoxide (DMSO), as a state-of-the-art CPA, is widely used for the storage of many types of cells. However, its intrinsic toxicity is still an obstacle for its applications in clinical practice. Herein, we report a DMSO analogue, L-methionine sulfoxide (Met(O)-OH), as a CPA for cell cryopreservation. The molecular-level cryopreservation roles of Met(O)-OH were investigated by experiments and molecular dynamics simulations. The results also found that Met(O)-OH showed high ice recrystallization inhibition (IRI) activity and the ice crystals in Met(O)-OH solution tend to be relatively round and smooth; moreover, the ice size was significantly reduced to 30.26 µm compared with pure water (135.87 µm) or DMSO solution (45.08 µm). At the molecular level, Met(O)-OH could stably bind the surface of the ice crystals and form more stable hydrogen bonds with ice compared with L-methionine. Moreover, Met(O)-OH could significantly reduce the damage to cells caused by osmotic shock and did not change the cell viability even at high concentration (4%). Based on these results, nucleated L929 cells and anuclear sheep red blood cells (SRBCs) were used as cell models to investigate the cryopreservation activity of Met(O)-OH. The results suggested that, under the optimum protocol, Met(O)-OH showed an effective post-thaw survival efficiency with ultrarapid freezing, and the post-thaw survival efficiency of L929 cells reached 84.0%. This work opens up the possibility for an alternative to traditional toxic CPA DMSO, and provides insights for the development of DMSO analogues with non-toxic/low toxicity for cell cryoprotection applications.

Observation-based sources evolution of non-methane hydrocarbons (NMHCs) in a megacity of China.

Both concentrations and emissions of many air pollutants have been decreasing due to implement of control measures in China, in contrast to the fact that an increase in emissions of non-methane hydrocarbons (NMHCs) has been reported. This study employed seven years continuous NMHCs measurements and the related activities data of Shanghai, a megacity in China, to explore evolution of emissions and effectiveness of air pollution control measures. The mixing ratio of NMHCs showed no statistical interannual changes, of which their compositions exhibited marked changes. This resulted in a decreasing trend of ozone formation potential by 3.8%/year (p < 0.05, the same below), which should be beneficial to ozone pollution mitigation as its production in Shanghai is in the NMHCs-limited regime. Observed alkanes, aromatics and acetylene changed by +3.7%/year, -5.9%/year and -7.4%/year, respectively, and alkenes showed no apparent trend. NMHCs sources were apportioned by a positive matrix factorization model. Accordingly, vehicular emissions (-5.9%/year) and petrochemical industry emissions (-7.1%/year) decreased significantly, but the decrease slowed down; significant reduction in solvent usage (-9.0%/year) appeared after 2010; however, emissions of natural gas (+12.6%/year) and fuel evaporation (with an increasing fraction) became more important. The inconsistency between observations and inventories was found in interannual trend and speciation as well as source contributions, emphasizing the need for further validation in NMHCs emission inventory. Our study confirms the effectiveness of measures targeting mobile and centralized emissions from industrial sources and reveals a need focusing on fugitive emissions, which provided new insights into future air policies in polluted region.

Polysaccharide-Derived Ice Recrystallization Inhibitors with a Modular Design: The Case of Dextran-Based Graft Polymers.

Ice recrystallization inhibitors inspired from antifreeze proteins (AFPs) are receiving increasing interest for cryobiology and other extreme environment applications. Here, we present a modular strategy to develop polysaccharide-derived biomimetics, and detailed studies were performed in the case of dextran. Poly(vinyl alcohol) (PVA) which has been termed as one of the most potent biomimetics of AFPs was grafted onto dextran via thiol-ene click chemistry (Dex-g-PVA). This demonstrated that Dex-g-PVA is effective in IRI and its activity increases with the degree of polymerization (DP) (sizes of ice crystals were 18.846 ± 1.759 and 9.700 ± 1.920 µm with DPs of 30 and 80, respectively) and fraction of PVA. By means of the dynamic ice shaping (DIS) assay, Dex-g-PVA is found to engage on the ice crystal surfaces, thus the ice affinity accounts for their IRI activity. In addition, Dex- g-PVA displayed enhanced IRI activity compared to that of equivalent PVA alone. We speculate that the hydrophilic nature of dextran would derive PVA in a stretch conformation that favors ice binding. The modular design can not only offer polysaccharides IRI activity but also favor the ice-binding behavior of PVA.

The gelatin-based liquid marbles for cell cryopreservation.

As an alternative and a straightforward cryopreservation biotechnological tool, liquid marble provides a promising cryopreservation approach. Currently, effective cell preservation mainly based on the addition of dimethyl sulfoxide (DMSO) and fetal bovine serum (FBS). As state-of-the-art cryoprotectant (CPA), DMSO, has intrinsic toxicity, which is the bottleneck of its widespread application. The complex compositions of FBS have the potential risks of pathogenic microorganism contamination. However, efficient cell cryopreservation using liquid marbles, a platform independent of DMSO and FBS, has not been well investigated yet. Herein, we explore the cryoprotection role of liquid marbles based on gelatin solution. Gelatin has a superior biocompatibility, which DMSO is incomparable. During a freeze-thaw cycle, gelatin produces negligible osmotic pressure, and has high ice recrystallization inhibition (IRI) activity to induce the formation of smaller and smooth ice crystals. Moreover, the specific structure of liquid marble also provides favorable supports for cell survival. The cryopreservation efficiency of mouse fibroblasts cells L929 via the gelatin-based liquid marble was as high as 90%, and the recovered cells could maintain their normal functionalities. This work opens a new window of opportunity for non-toxic and efficient cryopreservation of liquid marbles without the need of DMSO and FBS addition.

Visualizing and Understanding Shrinking Cities and Towns (SCT) Research: A Network Analysis.

The world is undergoing an unprecedented trend of fast urbanization, which causes a range of socio-environmental consequences, one of which is shrinking cities and towns (SCT). SCT refer to the cities or towns that are experiencing population decline and economic downturn. In the existing literature, there have been numerous studies on SCT; however, there is a lack of study which investigates its knowledge domains. Therefore, this paper aims to conduct a scientometric analysis to achieve an outline of the SCT research status. Through the procedures of literature search and screening, a total of 716 SCT-related studies were extracted from the Scopus. The VOSviewer software system program was then utilized to visualize the present SCT-related studies. The visualization results revealed that the journal of Sustainability made significant contributions to the SCT research in terms of relevant publications. In addition, Haase, Annegret received the most co-citations, and was also the most productive author in this field. Furthermore, it was identified that current SCT research is mainly conducted in developed countries. Through the analysis of keywords, the emerging research topics were revealed. Discussions were further made from the perspectives of prevailing research methods, evaluation criteria, and solutions for SCT problems.

Omentin-1 alleviate interleukin-1ß(IL-1ß)-induced nucleus pulposus cells senescence.

One of the main causes of low back pain (LBP) and degenerative musculoskeletal disorders is intervertebral disc degeneration (IVDD). Inflammation-associated senescence of Human nucleus pulposus cells (HNPCs) plays an essential function in the disease progression of IVDD. Omentin-1 is an adipokine that has been recently reported to have anti-inflammatory potential. In our research, IL-1ß was used to simulate the inflammatory environment in the IVDD. We investigated in vitro the effects of Omentin-1 on HNPCs, including the components of senescence, cell cycle and extracellular matrix (ECM) synthesis. The results showed that the addition of Omentin-1 improved IL-1ß-induced senescence in HNPCs. G1 phase cell cycle arrest and reduced ECM synthesis in HNPCs. Furthermore, we demonstrated that the effect of Omentin-1 in reducing senescence of HNPCs is dependent on SIRT1. These findings suggest that Omentin-1 plays an important function in protecting HNPCs against senescence and has the potential for IVDD gene target therapy.

Parkin-mediated mitophagy protects against TNF-α-induced stress in bone marrow mesenchymal stem cells.

Bone marrow mesenchymal stem cells (BMSCs) have been investigated as cellular therapeutics for intervertebral disc degeneration. However, transplanted BMSCs are prone to be damaged. TNF-α is reported to extensively promote degeneration process. Nevertheless, the relationship between BMSCs senescence and TNF-α-induced stress has not been elucidated. Previous studies showed that mitophagy is a crucial factor in maintaining cellular homeostasis. Hence, we sought to clarify the role and mechanism of mitophagy in TNF-α-induced biological changes of BMSCs. Here, we found that TNF-α caused transient senescent damage in the early stage. Meanwhile, Parkin-mediated mitophagy was initiated and weakened the damage through maintaining mitochondria homeostasis. After inhibiting mitophagy by knockdown of Parkin, TNF-α irreversibly caused cellular senescence. These results suggested that Parkin-mediated mitophagy played protective role in BMSCs in response to TNF-α, which could be a crucial therapeutic target in the future.

Transcription Factor KLF7 Promotes Osteoclast Differentiation by Suppressing HO-1.

Background: Osteoporosis is a common orthopedic disease with high prevalence in patients older than 50 years. Osteoporosis is often detected only after the fracture and is hard to treat. Therefore, it is of great significance to explore the molecular mechanism of the occurrence of osteoporosis. Methods: The expression of Heme oxygenase-1 (HO-1) in people with different bone mineral density (BMD) was analyzed based on public databases. GenHacncer and JASPAR databases were adopted to search and verify the upstream transcription factor of HO-1. qRT-PCR, western blot and tartrate-resistant acid phosphatase assays were performed to explore the impact of HO-1 and Kruppel-like factor 7 (KLF7) on osteoclast differentiation. Chromatin immunoprecipitation (ChIP) assay confirmed the binding relationship between KLF7 and HO-1. Finally, Hemin, the agonist of HO-1, was applied in rescue assays, thereby verifying the mechanism of KLF7 modulating osteoclast differentiation by HO-1. Results: Bioinformatics analysis revealed that HO-1 was highly-expressed while KLF7 lowly-expressed in people with high BMD. Besides, a potential binding site of KLF7 was found on the promoter region of HO-1. ChIP assay further manifested the targeting relationship between HO-1 and KLF7. Western blot and TRAP staining unveiled that osteoclast differentiation was suppressed by HO-1, while facilitated by KLF7. Rescue experiments indicated that over-expressed HO-1 could reverse of the promoting effect of KLF7 on osteoclast differentiation. Conclusion: The study confirmed that osteoclast differentiation was promoted by KLF7 constraining HO-1, thereby facilitating osteoporosis. The cognation of the pathogenesis of osteoporosis was further enriched. New treatment could be developed on this basis.

Injectable recombinant block polymer gel for sustained delivery of therapeutic protein in post traumatic osteoarthritis.

Protein-based biomaterials offer several advantages over synthetic materials, owing to their unique stimuli-responsive properties, biocompatibility and modular nature. Here, we demonstrate that E5C, a recombinant protein block polymer, consisting of five repeats of elastin like polypeptide (E) and a coiled-coil domain of cartilage oligomeric matrix protein (C), is capable of forming a porous networked gel at physiological temperature, making it an excellent candidate for injectable biomaterials. Combination of E5C with Atsttrin, a chondroprotective engineered derivative of anti-inflammatory growth factor progranulin, provides a unique biochemical and biomechanical environment to protect against post-traumatic osteoarthritis (PTOA) onset and progression. E5C gel was demonstrated to provide prolonged release of Atsttrin and inhibit chondrocyte catabolism while facilitating anabolic signaling in vitro. We also provide in vivo evidence that prophylactic and therapeutic application of Atsttrin-loaded E5C gels protected against PTOA onset and progression in a rabbit anterior cruciate ligament transection model. Collectively, we have developed a unique protein-based gel capable of minimally invasive, sustained delivery of prospective therapeutics, particularly the progranulin-derivative Atsttrin, for therapeutic application in OA.

Distinctive roles of tumor necrosis factor receptor type 1 and type 2 in a mouse disc degeneration model.

BACKGROUND: Elevated tumor necrosis factor alpha (TNF-α) expression is correlated with the progression of intervertebral disc degeneration (IVDD). Progranulin binding to tumor necrosis factor receptor (TNFR) and its derivative Atsttrin are effective for treating inflammatory arthritis. We hypothesize that Atsttrin has a protective effect in IVDD through different roles of TNFR receptor type 1 (TNFR1) and TNFR receptor type 2 (TNFR2) in degenerated discs. METHODS: IVDD models were established in TNFR1-/-, TNFR2-/- mice and their control littermates. Nucleus Pulpous (NP) samples from human patients and IVDD murine models were evaluated by X-ray, micro-MRI, µCT, histological staining and immunofluorescence staining. NP cells isolated from wild-type (WT), TNFR1-/- and TNFR2-/- mice were treated with TNF-α or Atsttrin and then assayed by Western blotting, qRT-PCR, and ELISA. RESULTS: TNFR1 and TNFR2 expression was significantly elevated in the disc tissues of both human patients and IVDD murine models. TNFR1 knockout contributed to reduced disc degeneration. In contrast, TNFR2 knockout was associated with enhanced IVDD severity, including degraded cellular composition, increased cell apoptosis and elevated vertebral destruction. Atsttrin protected against IVDD in WT and TNFR1-/- mouse models but had no effect in TNFR2-/- IVDD models. Additionally, in vitro NP cell-based assays demonstrated that TNF-α-stimulated catabolism and Atsttrin-activated anabolism depended on TNFR1 and TNFR2, respectively. CONCLUSION: TNFR1 is associated with the degenerative progression of IVDD, while TNFR2 contributes to the protective effect on the discs. Atsttrin protects against IVDD at least partially by inhibiting the TNFα/TNFR1 inflammatory/catabolic pathway and activating the TNFR2 protective/anabolic pathway. THE TRANSLATIONAL POTENTIAL OF THIS ARTICLE: This study demonstrates that TNFR1 and TNFR2 have disparate roles in disc degeneration and hlights the potential use of Atsttrin as a therapeutic agent against IVDD in mice.

Identification of a novel iron zinc finger protein 36 (ZFP36) for predicting the overall survival of osteosarcoma based on the Gene Expression Omnibus (GEO) database.

BACKGROUND: The purpose of this study is to explore the relationship between the ferroptosis-related gene zinc finger protein 36 (ZFP36) and the prognosis of osteosarcoma patients after surgery. METHODS: Differential expression genes (DEGs) between osteosarcoma and normal tissues were screened using osteosarcoma chip data in GEO database. Based on the median expression quantity, ferroptosis DEGs were divided into high and low expression groups. Combined with its corresponding clinical survival data, the survival analysis of ferroptosis DEGs was carried out using the Survival package, and ferroptosis-related genes related to prognosis were identified. Next, the clinical data of 60 osteosarcoma patients treated in Jiangyin Hospital Affiliated to Nanjing University of Chinese Medicine, Zhongda Hospital and Nanjing Drum Tower Hospital from January 2011 to January 2016 were retrospectively analyzed. Immunohistochemistry and reverse transcription quantitative polymerase chain reaction (qRT-PCR) were used to detect gene expression in osteosarcoma. The Kaplan-Meier method and log rank test were used for univariate survival analysis, the Cox regression method was used for multivariate analysis, and the nomogram was constructed for internal verification on this basis. RESULTS: Immunohistochemical and reverse transcription quantitative PCR results showed that the expression of ZFP36 was mainly higher in cancer-adjacent tissues than in tumor tissues. There were significant differences in age, tumor location, Enneking stage, and tumor specific growth factor (TSGF) between the high and low expression groups of ZFP36 (P<0.05). The final study included 60 patients, of whom 23 patients died (mortality rate: 38.33%), and 37 patients survived (survival rate: 61.67%), with a median progression-free survival (PFS) of 32.5 months and a median overall survival (OS) of 77 months. The Cox multivariate analysis showed that distant metastasis and ZFP36 were independent risk factors affecting tumor progression (P=0.021 and P=0.006, respectively). Elevated ZFP36 can significantly prolong the OS and PFS of osteosarcoma patients. In internal verification, the Concordance index (C-index) of the nomogram was 0.7211 [95% confidence interval (CI): 0.6308-0.8115], and the prediction model had certain accuracy. CONCLUSIONS: Elevated ZFP36 can significantly prolong the OS and PFS in osteosarcoma patients. At the same time, ZFP36 could be used as a new predictive biomarker and novel therapeutic target for osteosarcoma patients.

Integrative network analysis of N6 methylation-related genes reveal potential therapeutic targets for spinal cord injury.

The diagnosis of the severity of spinal cord injury (SCI) and the revelation of potential therapeutic targets are crucial for urgent clinical care and improved patient outcomes. Here, we analyzed the overall gene expression data in peripheral blood leukocytes during the acute injury phase collected from Gene Expression Omnibus (GEO) and identified six m6A regulators specifically expressed in SCI compared to normal samples. LncRNA-mRNA network analysis identified AKT2/3 and PIK3R1 related to m6A methylation as potential therapeutic targets for SCI and constructed a classifier to identify patients of SCI to assist clinical diagnosis. Moreover, FTO (eraser) and RBMX (reader) were found to be significantly down-regulated in SCI and the functional gene co-expressed with them was found to be involved in the signal transduction of multiple pathways related to nerve injury. Through the construction of the drug-target gene network, eight key genes were identified as drug targets and it was emphasized that fostamatinib can be used as a potential drug for the treatment of SCI. Taken together, our study characterized the pathogenesis and identified a potential therapeutic target of SCI providing theoretical support for the development of precision medicine.

lncRNA-KCNQ1OT1: A Potential Target in Exosomes Derived from Adipose-Derived Stem Cells for the Treatment of Osteoporosis.

BACKGROUND: Osteoporosis is a worldwide medical and socioeconomic burden characterized by systemic impairment of bone strength and microstructure. Exosomes derived from adipose-derived stem cells (ADSCs-Exos) have been confirmed to play effective roles in the repair of various tissues and organs. This study was aimed at investigating the role of ADSCs-Exos and a novel long noncoding RNA KCNQ1OT1 played in osteoporosis as well as the underlying mechanism. METHODS: Primary osteoblasts were treated with different doses of tumor necrosis factor-α (TNF-α) (0, 1, 2.5, 5, and 10 ng/ml) and then cocultured with ADSCs-Exos or exosome-derived from lnc-KCNQ1OT1-modified ADSCs (KCNQ1OT1-Exos). The expression of miRNA-141-5p (miR-141-5p) and lnc-KCNQ1OT1 was evaluated by quantitative real-time polymerase chain reaction (qRT-PCR). The protein expression of cleaved-caspase-3, caspase-3, and Bax was determined by Western blot. Cell viability and apoptosis were assessed by Cell Counting Kit-8 (CCK-8) and flow cytometry analysis, respectively. The binding sites between KCNQ1OT1 and miR-141-5p were validated by dual-luciferase reporter assay. RESULTS: TNF-α dose-dependently increased miR-141-5p expression, inhibited viability, and promoted apoptosis of osteoblasts. However, miR-141-5p silencing or cocultured with ADSCs-Exos attenuated these effects. In addition, KCNQ1OT1-Exos could more significantly attenuate the induced cytotoxicity and apoptosis compared to ADSCs-Exos. Moreover, miR-141-5p was confirmed as the target of KCNQ1OT1 by luciferase reporter assay. CONCLUSIONS: ADSCs-Exos can attenuate cytotoxicity and apoptosis of TNF-α-induced primary osteoblasts. KCNQ1OT1-Exos have a more significant inhibitory effect compared to ADSCs-Exos by the function of sponging miR-141-5p, suggesting that KCNQ1OT1-Exos can be promising agents in osteoporosis treatment.

Kinetics, isotherm and chemical speciation analysis of Hg(â ¡) adsorption over oxygen-containing MXene adsorbent.

A facile method was used to prepare two-dimensional MXene for the treatment of heavy metal ions in wastewater. The adsorbent has good selectivity for the adsorption of Hg (Ⅱ) in mixed divalent cationic metal solutions due to a large number of oxygen-containing functional groups on the surface of the material. The adsorption of mercury was tested using mercuric chloride and mercury nitrate solutions. The Langmuir maximum adsorption capacity of the adsorbent at a pH of 5.0 and a temperature of 30 °C is 1057.3 mg/g (mercuric nitrate) and 773.29 mg/g (mercuric chloride), respectively. The adsorbent also maintains a high adsorption capacity at low pH (pH = 2.0). The removal rate of mercury-containing wastewater within 100 mg/L is nearly 100%. The chemical species of Hg-containing ions at different pH and temperatures was studied. It was found that the adsorbent could maintain a high adsorption capacity for different forms of Hg-containing ions.

Interface phonon polariton coupling to enhance graphene absorption.

Here we present a graphene photodetector of which the graphene and structural system infrared absorptions are enhanced by interface phonon polariton (IPhP) coupling. IPhPs are supported at the SiC/AlN interface of device structure and used to excite interband transitions of the intrinsic graphene under gated-field tuning. The simulation results show that at normal incidence the absorbance of graphene or system reaches up to 43% or closes to unity in a mid-infrared frequency range. In addition, we found the peak-absorption frequency is mainly decided by the AlN thickness, and it has a red-shift as the thickness decreases. This structure has great application potential in graphene infrared detection technology.

Tracer-based characterization of source variations of PM2.5 and organic carbon in Shanghai influenced by the COVID-19 lockdown.

Air quality in megacities is significantly impacted by emissions from vehicles and other urban-scale human activities. Amid the outbreak of Coronavirus (COVID-19) in January 2020, strict policies were in place to restrict people's movement, bringing about steep reductions in pollution activities and notably lower ambient concentrations of primary pollutants. In this study, we report hourly measurements of fine particulate matter (i.e., PM2.5) and its comprehensive chemical speciation, including elemental and molecular source tracers, at an urban site in Shanghai spanning a period before the lockdown restriction (BR) (1 to 23 Jan. 2020) and during the restriction (DR) (24 Jan. to 9 Feb. 2020). The overall PM2.5 was reduced by 27% from 56.2 ± 40.9 (BR) to 41.1 ± 25.3 µg m-3 (DR) and the organic carbon (OC) in PM2.5 was similar, averaged at 5.45 ± 2.37 (BR) and 5.42 ± 1.75 µgC m-3 (DR). Reduction in nitrate was prominent, from 18.1 (BR) to 9.2 µg m-3 (DR), accounting for most of the PM2.5 decrease. Source analysis of PM2.5 using positive matrix factorization modeling of comprehensive chemical composition, resolved nine primary source factors and five secondary source factors. The quantitative source analysis confirms reduced contributions from primary sources affected by COVID-19, with vehicular emissions showing the largest drop, from 4.6 (BR) to 0.61 µg m-3 (DR) and the percentage change (-87%) in par with vehicle traffic volume and fuel sale statistics (-60% to -90%). In the same time period, secondary sources are revealed to vary in response to precursor reductions from the lockdown, with two sources showing consistent enhancement while the other three showing reductions, highlighting the complexity in secondary organic aerosol formation and the nonlinear response to broad primary precursor pollutants. The combined contribution from the two secondary sources to PM2.5 increased from 7.3 ± 6.6 (BR) to 14.8 ± 9.3 µg m-3 (DR), partially offsetting the reductions from primary sources and nitrate while their increased contribution to OC, from 1.6 ± 1.4 (BR) to 3.2 ± 2.0 µgC m-3 (DR), almost offset the decrease coming from the primary sources. Results from this work underscore challenges in predicting the benefits to PM2.5 improvement from emission reductions of common urban primary sources.