Bubbles in Porous Electrodes for Alkaline Water Electrolysis.

Porous electrodes with high specific surface areas have been commonly employed for alkaline water electrolysis. The gas bubbles generated in electrodes due to water electrolysis, however, can screen the reaction sites and hinder reactant transport, thereby deteriorating the performance of electrodes. Hence, an in-depth understanding of the behavior of bubbles in porous electrodes is of great importance. Nevertheless, since porous electrodes are opaque, direct observation of bubbles therein is still a challenge. In this work, we have successfully captured the behavior of bubbles in the pores at the side surfaces of nickel-based porous electrodes. Two types of porous electrodes are employed: the ones with straight pores along the gravitational direction and the ones with tortuous pores. In the porous electrodes with tortuous pores, the moving bubbles are prone to collide with the solid matrix, thereby leading to the accumulation of bubbles in the pores and hence bubble trapping. By contrast, in the porous electrodes with straight pores, bubbles are seldom trapped; and when two bubbles near the wall surfaces coalesce, the merged bubble can jump away from the wall surfaces, releasing more active surfaces for reaction. As a result, the porous electrodes with straight pores, although with lower specific surface areas, are superior to those with tortuous pores. The relationship among the pore structures of porous electrodes, bubble behavior, and electrode performance disclosed in this work provides deep insights into the design of porous electrodes.

Method for Measuring the Three-Dimensional Morphology of Near-Wall Bubbles and Droplets Based on LED Digital Holography.

Digital holography, recognized for its noncontact nature and high precision in three-dimensional imaging, is effectively employed to measure the morphology of bubbles and droplets. However, in terms of near-wall bubbles and droplets, such as confined bubbles in microfluidic chips, the measurement of the interface morphology of bubbles near the glass surface has not yet been resolved due to the coherent noise resulting from glass surface reflections in microfluidic chips. Accordingly, an off-axis digital holography system was devised by using Linnik interferometry. Measuring the confined bubble interface near the wall within a microfluidic chip and droplet evaporation on solid surfaces was studied. Partially coherent LED sources and reference light modulation techniques were employed in the optical setup to mitigate the coherent noise. Dual exposure and weighted least-squares unwrapping algorithms were introduced to correct phase distortions, enhancing image quality. Imaging two confined CO2 bubbles was done near the wall in silicon oil within a porous microfluidic chip, and contact angles of 4.7 and 4.5° were measured. Additionally, the measurement of the three-dimensional morphology of vertically evaporating deionized water droplets on a glass surface was done, due to which calculation of contact angles at various orientations was possible. This work offers a feasible new method for measuring the 3D interface morphology of bubbles and droplets, particularly in microfluidic visualization, addressing current measurement gaps.

Copper Nanoparticles Confined in a Silica Nanochannel Film for the Electrochemical Detection of Nitrate Ions in Water Samples.

The nitrate ion (NO3-) is a typical pollutant in environmental samples, posing a threat to the aquatic ecosystem and human health. Therefore, rapid and accurate detection of NO3- is crucial for both the aquatic sciences and government regulations. Here we report the fabrication of an amino-functionalized, vertically ordered mesoporous silica film (NH2-VMSF) confining localized copper nanoparticles (CuNPs) for the electrochemical detection of NO3-. NH2-VMSF-carrying amino groups possess an ordered perpendicular nanochannel structure and ultrasmall nanopores, enabling the confined growth of CuNPs through the electrodeposition method. The resulting CuNPs/NH2-VMSF-modified indium tin oxide (ITO) electrode (CuNPs/NH2-VMSF/ITO) combines the electrocatalytic reduction ability of CuNPs and the electrostatic attraction capacity of NH2-VMSF towards NO3-. Thus, it is a rapid and sensitive electrochemical method for the determination of NO3- with a wide linear detection range of 5.0-1000 µM and a low detection limit of 2.3 µM. Direct electrochemical detection of NO3- in water samples (tap water, lake water, seawater, and rainwater) with acceptable recoveries ranging from 97.8% to 109% was performed, demonstrating that the proposed CuNPs/NH2-VMSF/ITO sensor has excellent reproducibility, regeneration, and anti-interference abilities.

Classifying and characterizing the development of self-reported overall quality of life among the Chinese elderly: a twelve-year longitudinal study.

BACKGROUND: To promote healthy aging, the information about the development of quality of life (QoL) is of great importance. However, the explorations of the heterogeneity in the change of QoL under the Chinese context were limited. This study aimed to identify potential different development patterns of QoL and the influential factors using a longitudinal, nationally representative sample of the Chinese elderly. METHODS: We adopted a five-wave longitudinal dataset from the Chinese Longitudinal Healthy Longevity Survey (CLHLS), and a total of 1645 elderly were obtained. The sample had a mean age of 72.7 years (SD = 6.64) and was 47.2% male. Overall QoL was measured through self-report during the longitudinal process. We utilized the conditional growth mixture model (GMM) with time-invariant covariates (TICs) to explore various development patterns and associated factors. RESULTS: Three distinct trajectories of self-reported overall QoL were identified: the High-level Steady Group (17.08%), the Mid-level Steady Group (63.10%), and the Low-level Growth Group (19.82%). Results also indicated that several factors predicted distinct trajectories of self-reported overall QoL. Those elderly who received enough financial resources, had adequate nutrition, did not exhibit any disability, engaged in leisure activities, and did less physical labor or housework at the baseline were more likely to report a higher level of overall QoL over time. CONCLUSIONS: There existed three development patterns of self-reported overall QoL in elders, and the findings provided valuable implications for the maintenance and improvement of QoL among the Chinese elderly. Future studies could examine the influence of other confounding factors.

Improvements on biological and antimicrobial properties of titanium modified by AgNPs-loaded chitosan-heparin polyelectrolyte multilayers.

Microbial infection around dental implants is a major cause for the loss of devices, including soft tissue infection in early period, post-operation peri-implantitis, and osseointegration failure. Silver nanoparticles (AgNPs) with wide antimicrobial spectrum, strong antimicrobial effect and hypotoxicity, as well as low incidence of antibiotic resistance, are widely involved in biomedical applications. Herein, firmly anchoring AgNPs onto the surface of implants through physical-chemical reaction is likely to relieve the above issues. In this study, AgNPs were biosynthesized by a simple and "green" method with chitosan (CS) as stabilizing and reducing agents. Then, AgNPs-loaded CS-heparin polyelectrolyte multilayers (PEMs) were constructed on alkali-heat treated titanium (Ti) substrates via layer-by-layer (LbL) self-assembly technique. The successful surface modification could be confirmed by scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), and the constructed system could provide the continuous release of Ag+ over 28 days till mucosa healing. In short, this work revealed that the construction of multilayer coatings containing AgNPs on Ti substrates promoted adhesion and proliferation of human gingival fibroblasts (HGFs) and also enhanced the antimicrobial properties. This manifests the LbL technique is a viable and promising method for forming continuous antimicrobial coatings, to reduce microbial infection and improve the quality of peri-implant soft tissue seal. The preparation process of AgNPs-loaded CS-heparin PEMs on Ti substrate.

Global annual wetland dataset at 30 m with a fine classification system from 2000 to 2022.

Wetlands play a key role in maintaining ecological balance and climate regulation. However, due to the complex and variable spectral characteristics of wetlands, there are no publicly available global 30-meter time-series wetland dynamic datasets at present. In this study, we present novel global 30 m annual wetland maps (GWL_FCS30D) using time-series Landsat imagery on the Google Earth Engine platform, covering the period of 2000-2022 and containing eight wetland subcategories. Specifically, we make full use of our prior globally distributed wetland training sample pool, and adopt the local adaptive classification and spatiotemporal consistency checking algorithm to generate annual wetland maps. The GWL_FCS30D maps were found to achieve an overall accuracy and Kappa coefficient of 86.95 ± 0.44% and 0.822, respectively, in 2020, and show great temporal variability in the United States and the European Union. We expect the dataset would provide vital support for wetland ecosystems protection and sustainable development.

IGFBP7 promotes gastric cancer by facilitating epithelial-mesenchymal transition of gastric cells.

Gastric cancer (GC) with high morbidity and mortality is one major cause of tumor-related death. Mechanisms underlying GC invasion and metastasis remain unclear. IGFBP7 exerted variable effects in different cancers and its role in GC is controversial. Here, IGFBP7 was found to be upregulated and elevated IGFBP7 expression represented a poorer overall survival in GC using bioinformatics analysis. Moreover, IGFBP7 was up-regulated in human GC specimens and promoted tumor growth in xenograft tumor animals. For GC cell lines, we found that IGFBP7 was also upregulated and facilitated the cell malignant behavior and EMT of GC cells, which may involve NF-κB and ERK signaling pathways. This research may provide new avenues for GC therapy.

Green synthetic sodium alginate-glycerol-MXene nanocomposite membrane with excellent flexibility and mineralization ability for guided bone regeneration.

Developing a novel bioactive material as a barrier membrane for guided bone regeneration (GBR) surgery remains challenging. As a new member of two-dimensional (2D) material family, MXene is a promising candidate component for barrier membranes due to its high specific surface area and osteogenic differentiation ability. In this work, a green and simple SA/glycerol/MXene (SgM) composite membrane was prepared via solvent casting method by using sodium alginate (SA) and MXene (M) as raw materials while employing glycerol (g) as a plasticizer. The addition of glycerol significantly increased the elongation at the break of SA from 10%-20% to 240%-360%, while the introduction of MXene promoted the deposition of calcium and phosphorus to form hydroxyapatite. At the same time, the roughness of the SgM composite membrane is apparently improved, which is conducive to cell adhesion and proliferation. This work provides a basis for further research on SgM composite membrane as GBR membrane for the treatment of bone defects.

USP12 facilitates gastric cancer progression via stabilizing YAP.

The dysregulation of Hippo signaling is a crucial factor driving the progression of gastric cancer, making the targeting of the Hippo pathway a promising therapeutic strategy. However, effective drugs targeting the Hippo/YAP axis remain unavailable. Thus, identifying potential therapeutic targets and mechanisms that inhibit the activity of the Hippo/YAP axis in gastric cancer is of paramount importance. The ubiquitination modification of the Hippo/YAP pathway plays a significant role in signaling transduction and cancer progression. In an effort to shed light on effective therapeutic targets, we conducted a screening using a deubiquitinase small interfering RNA library, leading to the identification of USP12 as an important deubiquitinase in the context of Hippo/YAP axis and the progression of gastric cancer. Our bioinformatic analysis further demonstrated a correlation between USP12 and poor survival, as well as a positive association with classical YAP target genes in gastric cancer samples. Notably, USP12 depletion was found to inhibit gastric cancer progression via the Hippo/YAP axis, whereas USP12 overexpression exhibited the opposite effect, promoting gastric cancer growth and enhancing YAP activity. Further studies through immuno-staining and immuno-precipitation assays indicated the nuclear localization of USP12 and its association with YAP to enhance YAP stability. Specifically, our findings revealed that USP12 could inhibit K48-linked poly-ubiquitination of YAP, predominantly at the K315 site. As a result, we have identified a novel regulatory mechanism involving USP12 and Hippo signaling in the progression of gastric cancer, with the potential for blockade of USP12 to materialize as a promising strategy for combating gastric cancer.

Distribution of gasification products and emission of heavy metals and dioxins from municipal solid waste at the low temperature pyrolysis stage.

Gasification is widely regarded as one of the most practical, economical, and environmentally friendly waste disposal technologies for municipal solid waste (MSW). The pyrolysis stage (300-500 °C) is crucial for weight loss during MSW gasification, as a considerable amount of organic matter breaks down, producing high-value synthesis gas. This study investigated the product distribution and pollutant emission characteristics within this temperature range and its influencing factors during MSW gasification using a self-designed MSW gasification device. Results indicated that MSW underwent approximately 70% weight loss within this temperature range, yielding low amounts of inorganic and short-chain organic products, with mainly long-chain organic compounds of C16-C34. The atmosphere variation had minimal effect on the elemental composition and content of solid phase products. X-ray fluorescence spectrometry (XRF) and inductively coupled plasma mass spectrometry (ICP-MS) analyses showed that Mn and Zn were the primary components of heavy metal leaching toxicity in solid phase products, with their contents increasing as temperature increased. Synthesis gas showed the highest content of heavy metal As element, reaching a peak at 400 °C. Higher gasification temperature and lower oxygen flow rate significantly reduced the dioxin content and I-TEQ values, with highly chlorinated isomers being the predominant dioxin isomers. Nonetheless, low-chlorinated dioxins accounted for more than 50% of the I-TEQ. This study improves our understanding of the gasification process of MSW.

Biodegradable polyvinyl alcohol/nano-hydroxyapatite composite membrane enhanced by MXene nanosheets for guided bone regeneration.

MXene, as a new category of two-dimensional nanomaterials, exhibits a promising prospect in biomedical applications due to its ultrathin structure and morphology, as well as a range of remarkable properties such as biological, chemical, electronic, and optical properties. In this work, different concentrations of MXene (M) were added to polyvinyl alcohol (PVA, P)/nano-hydroxyapatite (n-HA, H) mixed solution, and series of PVA/n-HA/MXene (PHM) composite membranes were obtained by combining sol-gel and freeze-drying processes. Morphology, chemical composition, surface, and mechanical properties of the prepared PHM membranes were characterized by various techniques. Subsequently, the swelling and degradation performances of the composite membranes were tested by swelling and degradation tests. In addition, in vitro studies like cell adhesion, cytotoxicity, proliferation, osteogenic differentiation, and antibacterial properties of MC3T3-E1 were also evaluated. The results showed that the addition of MXene could apparently improve the composite membranes' physicochemical properties, bioactivity, and osteogenic differentiation. Specially, PHM membrane had the best comprehensive properties when the concentration of MXene was set as 2.0% w/v. In a word, the addition of MXene has a positive effect on improving the mechanical properties, osteogenic induction, and antibacterial properties of PH composite membranes, and the prepared PHM composite membranes possess potential applications for guided bone regeneration.

MXene/Silk Fibroin Strengthened PVA-Based Eutectogel with Excellent Self-Healing Ability and Environmental Adaptability: Design, Synthesis, and Sensing Application.

A superelastic self-healing eutectogel was designed and prepared using poly (vinyl alcohol) (PVA) as the bulk skeleton material, while silk fibroin (SF) and two-dimensional (2D) MXene (Ti3C2TX) as reinforcing fillers. In brief, the eutectogel possesses a high tensile strength of 7.63 MPa, and its elongation at break reached 1115.2%, higher than most reported polymers (<1000%). In addition, the eutectogel-assembled sensor has a high ionic conductivity of 0.61 S/m and a high strain sensitivity of 5.17 kPa-1. Moreover, eutectogel shows excellent self-healing ability and can achieve self-healing quickly within 10 min, while its tensile strength and elongation at break can be restored to 84.7% and 97.4% of the initial levels. Besides, a stable electrical signal can be transmitted after 200 cycles at 30% strain. Finally, the eutectogel can withstand various environmental conditions, such as atmospheric or even vacuum evaporation and low-temperature freezing, while maintaining good mechanical and sensing performances. The assembled flexible sensors based on the eutectogel demonstrate their significant application prospects in wearable devices, especially human physiological monitoring.

Biodegradable and biocompatible alginate/gelatin/MXene composite membrane with efficient osteogenic activity and its application in guided bone regeneration.

Guided bone regeneration (GBR) utilizes a barrier membrane to maintain the osteogenic space and promote osseointegration of the implants. Developing a novel biomaterial to meet the mechanical and biological performance requirements of GBR membrane (GBRM) remains a huge challenge. Here, the sodium alginate (SA, S)/gelatin (G)/MXene (M) composite membrane (SGM) was prepared by combining sol-gel and freeze-drying processes. The incorporation of MXene improved the mechanical properties and hydrophilicity of the SA/G (SG) membrane, and also enhanced its cell proliferation and osteogenic differentiation. More importantly, when the concentration of MXene is 0.25%W/V, the SGM composite membrane exhibited the best tensile strength (40 MPa), high swelling rate (1012%), and appropriate degradation rate (40%). Meanwhile, the biological improvements were more significant. Therefore, the appropriate amount addition of MXene has a positive and obvious effect on the improvements of the mechanical properties, biocompatibility, and osteogenic induction of the SG composite membranes. This work provides a more extendable development idea for the application of SGM composite membrane as GBRM.

An Armour Structure to Suppress the Brittle Failure of Ceramic Coatings.

The brittle failure of ceramic coatings limits their application in many fields. To address this issue, a novel armoured ceramic coating was developed to suppress brittle failure. First, an interconnected frame microstructure was micromachined onto the surface of a mild steel substrate using a nanosecond laser. Subsequently, a polymer-derived ceramic slurry was sprayed and sintered to obtain an armoured ceramic coating. The laser-micromachined burr-like microstructure of the substrate facilitated adhesion between the coating and the substrate. The results of the mechanical properties test showed that the armoured coating could withstand more than 20 cycles of water-cooled thermal shock at 600 °C, and the peeling area of the armoured coating was approximately three times less than that of the unarmoured coating under a normal load of 1471 N. The laboratory and field corrosion test results indicated that at high temperatures, the corrosion resistance of the armoured coating was comparable with that of the unarmoured coating and was approximately 10 times higher than that of the uncoated sample. The proposed method will aid in suppressing the brittle failure of ceramic coatings and broaden their scope of application in different fields.

Synergetic degradation of perfluorooctanoic acid (PFOA) in soil using electrical resistance heating induced persulfate activation.

Due to wastes from production of fluorinated materials and use of aqueous fire-fighting foams (AFFF), soils contaminated with perfluorooctanoic acid (PFOA) is of concern. However, current PFOA-contaminated soil disposal techniques have relatively low degradation efficiencies and are not suitable for on-site remediation. In this study, an electrical resistance heating (ERH) device and a box experimental device were used to study whether ERH induced persulfate activation (ERH/PS) could degrade PFOA in the soil. The results indicated that single ERH and single PS addition could not effectively degrade PFOA (with approximately 0.3 % and 3.9 % degradation after 9 h, respectively), while the degradation efficiency of PFOA with coupled ERH/PS could reach 87.3 % after 9 h of reaction. Moreover, effects of PS content, heating temperature, and soil organic matter on the degradation of PFOA were explored. During the ERH/PS process, PFOA was gradually transformed into short chain perfluorinated compounds and finally mineralized to fluoride ions. Finally, using a box experimental device, PS was effectively transported to the target contaminated area through electrokinetic (EK)-assisted delivery. After activating PS through ERH, the degradation rate of PFOA could reach 95.5 %. This is a novel study demonstrating the feasibility of ERH induced PS activation to degrade PFOA in soil, which provides a potential on-site strategy for remediation of PFOA-contaminated soil.

Combined effect of cytokine gene polymorphisms on end-stage knee osteoarthritis from Chinese Han population.

The mechanism of osteoarthritis (OA) is not well understood. Cytokines have been implicated in the episode, and there is increasing evidence that the host's cytokine response is genetically determined. We determined the predictive value of IL-634G./C, ICAM-1 469 K/E and IL-10-1082A/G, -819T/C and -592A/C gene polymorphisms on knee OA. The study included 1007 patients with end-stage knee OA and 910 healthy controls. Genomic DNA was prepared from peripheral blood leukocytes. Genotypes and allele frequencies were determined using restriction fragment length polymorphism analysis of polymerase chain reaction products. No significant difference in the IL-10 promoter allele or haplotype frequencies between end-stage knee OA and controls was found. Patients with end-stage knee OA showed a significantly higher prevalence of IL-6-634G/ICAM-1 469E carrier than that in controls (P = 0.017). Results indicate that IL-6-634G/ICAM-1 469E carrier could be associated with increased susceptibility to end-stage knee OA.

Effects of the COVID-19 Pandemic on Chinese Graduate Students' Learning Activities: A Latent Class Analysis.

To investigate the impact of the pandemic on graduate students' learning activities, a series of questionnaires were distributed to graduate students in universities across China, and 2,818 responses were collected. A latent class analysis was performed to classify the effects of the pandemic on graduate students' learning activities. Then, a multinomial logistic regression analysis and an analysis of variance analysis were carried out to explore the impact of demographic variables on the classification and their mental health status. The analysis identified four latent classes: "the overall less affected" (34.83%), "the overall more affected" (31.97%), "course activities were more affected" (19.40%), and "social activities were more affected" (13.79%). The multinomial logistic regression analysis indicated that during the pandemic, the learning activities of graduate students in all grades were affected to varying degrees, and the impacts on second-year and third-year graduate students were greater than those of first-year graduate students. The analysis of variance revealed that the scores for anxiety, depression, and social anxiety of "the overall more affected" were significantly greater than those of the other three groups, and nearly one-third of students belonged to this class, suggesting that more attention and care should be given to these students. As a result of the COVID-19 pandemic, a number of graduate students have suffered mental problems (anxiety and depression). Under the current backdrop of a new normal, schools and teachers should pay attention to graduate students' mental health, providing targeted assistance to different types of students.

The Difference in Learning Activities of Postgraduate Students of Different Qualification Types Under the COVID-19 Pandemic: A Multi-Group Latent Class Analysis.

Introduction: There are two types of master's qualifications in China. One is the academic qualification that pays more attention to academic research, aiming to cultivate research-oriented talents; while the other is the application-oriented qualification that focuses more on practical ability, aiming to cultivate applied-oriented talents. The purpose of this study is to explore the impact of the COVID-19 on the learning activities of postgraduate students, as well as the differences in the extent to which the learning activities of postgraduate students of different qualification types are affected and their mental health status. Methods: A self-constructed scale for the pandemic's impact on master's students, the self-rating anxiety scale and the self-rating depression scale were applied in the study. The single- and multi-group latent class analyses were used to investigate the impact of the pandemic on postgraduate students of different qualification types. Results: A total of 2818 responses were collected. The single-group latent class analysis identified four classes. The multi-group latent class analysis showed that no absolute homogeneity existed between different groups. In general, the number of academic master's students affected was greater than application-oriented master's students. Application-oriented master's students were more affected by course activities, while academic master's students were more affected by academic and social activities. Results show that individuals more affected had higher levels of anxiety and depression. Compared to course activities, impacts on social activities were more likely to cause anxiety and depression. Discussion: Universities can provide a more flexible way of assistance to different qualification types of postgraduate students. Furthermore, social activities play an important role in the mental health of postgraduate students. Therefore, under the background of normalization of pandemic prevention and control, schools should pay more attention to students' interpersonal communication activities to help relieve students' anxiety, depression, and other negative emotions.

Heat- and freeze-tolerant organohydrogel with enhanced ionic conductivity over a wide temperature range for highly mechanoresponsive smart paint.

Binary solvent-based fabrication permits the conductive organohydrogel to function well at low-temperature environments. However, the deep cryogenic and high temperatures are still threatening the performance of conductive organohydrogels in the application of stretchable electronics, biosensors, and intelligent coatings. Here, a radically new method is developed to introduce propylene and carbonate cellulose nanofibrils into freeze tolerance polymer matrix, and fabricate an antifreezing/antiheating organohydrogel integrated a high mechanical strength (1.6 MPa) and high level of ionic conductivity (4.2 S cm-1) over a wide temperature range (-40 to 100 °C). In this designed system, the propylene carbonate with low freezing point and high boiling point was shown to enhance antifreezing (-40 °C) and antiheating (100 °C) performance of organohydrogel. Furthermore, negative charge-rich cellulose nanofibrils (CNFs) were served as an ion transport channel and nanoreinforcements to boost the conductive and mechanical properties of the organohydrogel. In particular, Molecular Dynamics (MD) simulations reveal that propylene carbonate with high dielectric constant is capable of generating ion migration-facilitated effects, enabling the high ionic conductivity of organohydrogel. Tapping into these attributes, potential applications in mechanoresponsive smart coating have been demonstrated utilizing the appealing organohydrogel as a paint, rendering unprecedented protection and monitoring performance.