Simulation and Study of Influencing Factors on the Solidification Microstructure of Hazelett Continuous Casting Slabs Using CAFE Model.

The Hazelett continuous casting and rolling process represents a leading-edge production method for cold-rolled aluminum sheet and strip billets in the world. Its solidification microstructure significantly influences the quality of billets produced for cold rolling of aluminum sheets and strips. In this study, employing the CAFE (Cellular Automaton-Finite Element) method, we developed a coupled computational model to simulate the solidification microstructure in the Hazelett continuous casting process. We investigated the impact of nucleation parameters, casting temperature, and continuous casting speed on the microstructural evolution of the continuous casting billet. Through integrated metallographic analyses, we aimed to elucidate the controlling mechanisms underlying the Hazelett continuous casting process and its resultant microstructure. The results demonstrate that the equiaxed rate of grains increases with an increase in nucleation density, and the grain size decreases under constant cooling strength. With other nucleation parameters held constant, the grain size decreases as undercooling increases, and the columnar crystal zone expands. The nucleation density of the Hazelett continuous casting aluminum alloy has been determined to range between 1011 m-3 and 1013 m-3, and the undercooling ranges between 1 °C and 2.5 °C. The solidified grain structure can be controlled between 35 µm and 72 µm. The grain size of the continuous casting billet increases with an increase in pouring temperature and decreases as the casting speed increases. Elevating the pouring temperature positively impacts the fraction of high-angle grain boundaries and promotes the dendritic to equiaxed grain transition. Moreover, there exists potential for further optimization of continuous casting process parameters.

Composite of CoS1.97 nanoparticles decorated CuS hollow cubes with rGO as thin film electrode for high-performance all solid flexible supercapacitors.

Stretchable flexible thin-film electrodes are extensively explored for developing new wearable energy storage devices. However, traditional carbon-based materials used in such independent electrodes have limited practical applications owing to their low energy storage capacity and energy density. To address this, a unique structure and remarkable mechanical stability thin-film flexible positive electrode comprising CoS1.97 nanoparticles decorated hollow CuS cubes and reduced graphene oxide (rGO), hereinafter referred to as CCSrGO, is prepared. Transition metal sulfide CoS1.97 and CuS shows high energy density owing to the synergistic effects of its active components. The electrode can simultaneously meet the high-energy density and safety requirements of new wearable energy storage devices. The electrode has excellent electrochemical performance (1380 F/g at 1 A/g) and ideal capacitance retention (93.8 % after 10,000 cycles) owing to its unique three-dimensional hollow structure and polymetallic synergies between copper and cobalt elements, which are attributed to their different energy storage mechanisms. Furthermore, a flexible asymmetric supercapacitor (FASC) was constructed using CCSrGO as the positive electrode and rGO as the negative electrode (CCSrGO//rGO), which delivers an energy density of 100 Wh kg-1 and a corresponding power density of 2663 W kg-1 within a voltage window of 0-1.5 V. The resulting FASC can power a light-emitting diode (LED) at different bending and twisting angles, exerting little effect on the capacitance. Therefore, the prepared CCSrGO//rGO FASC devices show great application prospects in energy storage.

Injectable and Thermosensitive Hydrogel with Platelet-Rich Plasma for Enhanced Biotherapy of Skin Wound Healing.

The rapid and effective healing of skin wounds resulted from severe injuries and full-layer skin defects remains a pressing clinical challenge in contemporary medical practice. The reduction of wound infection and rapid healing is helpful to rebuild and repair skin tissue. Here, a thermosensitive chitosan-based wound dressing hydrogel incorporating ß-glycerophosphate (GP), hydroxy propyl cellulose (HPC), graphene oxide (GO), and platelet-rich plasma (PRP) is developed, which exhibits the dual functions of antibacterial properties and repair promotion. GP and HPC enhance the mechanical properties through forming hydrogen bonding connection, while GO produces local heat under near-infrared light, leading to improved blood circulation and skin recovery. Notably, antibacterial properties against Pseudomonas aeruginosa, and control-release of growth factors from PRP are also achieved based on the system. In vitro experiments reveal its biocompatibility, and ability to promote cell proliferation and migration. Animal experiments demonstrate that the epithelial repair and collagen deposition can be promoted during skin wound healing in Sprague Dawley rats. Moreover, a reduction in wound inflammation levels and the improvement of wound microenvironment are observed, collectively fostering effective wound healing. Therefore, the composite hydrogel system incorporated with GO and PRP can be a promising dressing for the treatment of skin wounds.

Research Progress on Nanomaterials for Tissue Engineering in Oral Diseases.

Due to their superior antibacterial properties, biocompatibility and high conductivity, nanomaterials have shown a broad prospect in the biomedical field and have been widely used in the prevention and treatment of oral diseases. Also due to their small particle sizes and biodegradability, nanomaterials can provide solutions for tissue engineering, especially for oral tissue rehabilitation and regeneration. At present, research on nanomaterials in the field of dentistry focuses on the biological effects of various types of nanomaterials on different oral diseases and tissue engineering applications. In the current review, we have summarized the biological effects of nanoparticles on oral diseases, their potential action mechanisms and influencing factors. We have focused on the opportunities and challenges to various nanomaterial therapy strategies, with specific emphasis on overcoming the challenges through the development of biocompatible and smart nanomaterials. This review will provide references for potential clinical applications of novel nanomaterials in the field of oral medicine for the prevention, diagnosis and treatment of oral diseases.

Strong Ti3 C2 Tx MXene-Based Composite Films Fabricated through Bioinspired Bridging for Flexible Energy Storage Devices.

Flexible energy storage device is one of the most critical components as power source for wearable electronics. The emergence of MXenes, a growing family of 2D nanomaterials, has demonstrated a brand-new possibility for flexible energy storage. However, the fabrication of MXene films with satisfactory mechanical, electrical, and electrochemical reliabilities remains challenging due to the weak interlayer interactions and self-restacking of MXene sheets. Sequential bridging of polydopamine/polyethyleneimine-functionalized (PDA/PEI)-coated MXene sheets to induce synergistically covalent and hydrogen binding connections of MXene-based films is demonstrated here. By interrupting self-hydrogen bonding and π-π stacking interactions, the introduction of long-chain PEI can not only inhibit the massive aggregation of PDA, but also improve the continuity of the interconnection network of PDA/PEI between MXene layers. Hence, the as-prepared MXene/PDA/PEI composite film displays high mechanical strength (≈366 MPa) which achieves 12-fold improvement compared with pure MXene film, as well as superior energy storage capability (≈454 F g-1  at 5 mV s-1 ) and rate performance of ≈48% at 10 000 mV s-1 . This modulation of inserted polymer between MXene layers can provide an avenue for assembling high performance MXene films, and can even be extended to the fabrication of other 2D platelets for varied applications.

Compression-tolerant supercapacitor based on NiCo2O4/Ti3C2Tx MXene/reduced graphene oxide composite aerogel with insights from density functional theory simulations.

Compression-tolerant electrodes are critical for developing next-generation wearable energy storage devices. However, most of previous studies on compressible electrodes focus on carbon-based materials, whereas metal-based materials such as spinel metal oxide with faradaic nature have been rarely studied due to their lack of compressibility. Herein, NiCo2O4 (NCO) microtubes assembled by ultrathin and mesoporous nanosheets, are deposited on/into Ti3C2Tx MXene/reduced graphene oxide aerogel (MGA), an intrinsically compressible host template with high conductivity and specific surface areas. The optimized NCO/MGA-300 sample shows a reversible compressive strain of 60% and a superior durability. Density functional theory (DFT) calculations reveal that the NCO/MGA-300 heterojunction has high electronic conductivity, fast electron transfer ability, and low adsorption energy for OH- ions. As a result, the NCO/MGA-300 electrode exhibits superb electrochemical performance in terms of its high gravimetric capacitance (1633F g-1 at 1 A g-1), rate performance (1492F g-1 at 10 A g-1), and remarkable cycling stability of 86.6% after 10,000 charge-discharging cycles. Moreover, an assembled asymmetric supercapacitor based on compressible NCO/MGA-300 shows stable electrochemical performances under different compressive strains (20%. 40% and 60%), or after 100 compression-release cycles. This research finding demonstrates the possibility of metal-based electrode for wearable devices with high energy storage capability and good compressibility.

The Role of Oral Nitrate-Reducing Bacteria in the Prevention of Caries: A Review Related to Caries and Nitrate Metabolism.

Circulating nitrate is actively absorbed by salivary glands and secreted into the oral cavity, where it is reduced to nitrite by oral nitrate-reducing bacteria. This process has previously been considered harmful because nitrate and nitrite can promote the formation of potentially carcinogenic N-nitrosamines. However, recent studies have shown that nitrate may have other physiological functions, and it can serve as a precursor for the systemic production of nitric oxide (NO) and perform NO-like functions, such as promoting vasodilation, regulating metabolic diseases, alleviating senescence, and protecting the digestive system. Inside the oral cavity, NO is likely to inhibit sensitive species as part of the nonspecific oral immune system. Exogenous administration of nitrate can maintain a balance in the pH of saliva. Oral nitrate-reducing bacteria can control the progression of caries by metabolizing lactic acid and reducing its accumulation, which is beneficial to the homeostasis of the oral microecology. In the current manuscript, we reviewed nitrate-reducing bacteria and their nitrate-metabolizing functions during the development of caries. Furthermore, we listed the effects of probiotics and dietary modification, which may be a promising method to prevent the occurrence of caries. We believe that this review provides novel ideas for the prevention of caries and treatment in clinical settings.

LncRNA NEAT1 Recruits SFPQ to Regulate MITF Splicing and Control RPE Cell Proliferation.

Purpose: Retinal pigment epithelium (RPE) cell proliferation is precisely regulated to maintain retinal homoeostasis. Microphthalmia-associated transcription factor (MITF), a critical transcription factor in RPE cells, has two alternatively spliced isoforms: (+)MITF and (-)MITF. Previous work has shown that (-)MITF but not (+)MITF inhibits RPE cell proliferation. This study aims to investigate the role of long non-coding RNA (lncRNA) nuclear-enriched abundant transcript 1 (NEAT1) in regulating MITF splicing and hence proliferation of RPE cells. Methods: Mouse RPE, primary cultured mouse RPE cells, and different proliferative human embryonic stem cell (hESC)-RPE cells were used to evaluate the expression of (+)MITF, (-)MITF, and NEAT1 by reverse-transcription PCR (RT-PCR) or quantitative RT-PCR. NEAT1 was knocked down using specific small interfering RNAs (siRNAs). Splicing factor proline- and glutamine-rich (SFPQ) was overexpressed with the use of lentivirus infection. Cell proliferation was analyzed by cell number counting and Ki67 immunostaining. RNA immunoprecipitation (RIP) was used to analyze the co-binding between the SFPQ and MITF or NEAT1. Results: NEAT1 was highly expressed in proliferative RPE cells, which had low expression of (-)MITF. Knockdown of NEAT1 in RPE cells switched the MITF splicing pattern to produce higher levels of (-)MITF and inhibited cell proliferation. Mechanistically, NEAT1 recruited SFPQ to bind directly with MITF mRNA to regulate its alternative splicing. Overexpression of SFPQ in ARPE-19 cells enhanced the binding enrichment of SFPQ to MITF and increased the splicing efficiency of (+)MITF. The binding affinity between SFPQ and MITF was decreased after NEAT1 knockdown. Conclusions: NEAT1 acts as a scaffold to recruit SFPQ to MITF mRNA and promote its binding affinity, which plays an important role in regulating the alternative splicing of MITF and RPE cell proliferation.

Proteobacteria Acts as a Pathogenic Risk-Factor for Chronic Abdominal Pain and Diarrhea in Post-Cholecystectomy Syndrome Patients: A Gut Microbiome Metabolomics Study.

BACKGROUND Laparoscopic cholecystectomy (LC) is regarded as the criterion standard for gallstone therapy, but post-cholecystectomy syndrome (PCS) is a common complication. This study aimed to analyze and identify differences in gut microbiome in PCS patients. MATERIAL AND METHODS This study involved 8 PCS patients (RS1), 8 asymptomatic PCS patients (RS2), and 8 healthy individuals (RS3). Genomic DNA of gut microbiome was extracted and amplified with CTAB method. PCR products were sequenced with Illumina High-Through Sequencing. Sequencing data were analyzed with QIIME software. Effective sequence of bacterial 16S-rRNA gene was clustered into OTUs using UPARSE software. Species annotations were evaluated using Mothur software. QIIME software was used to conduct complexity analysis and calculate UniFrac distances. R software was used to generate PCoA plots. RESULTS Bacterial 16S-rDNA gene sequences showed that the effective species annotative data were more than 97%. According to Ternary plot, Firmicutes and Bacteroidetes had similar abundance and contents among the 3 groups. Contents of Proteobacteria in RS1 were higher compared to RS2 and RS3. Bacterial genomic DNAs samples were clustered together in the same group; however, distances were relative far between different groups. RS1 illustrated significantly higher abundance of Proteobacteria colonies compared to healthy people (p<0.05), and illustrated higher abundance of Verrucomicrobia and lower abundance of Bacteroidetes and Firmicutes, but without significant differences (p>0.05). CONCLUSIONS Gut microbiome of PCS patients was dominated by Proteobacteria in feces and contained little Firmicutes and Bacteroidetes. The enhanced abundance of Proteobacteria might be the highly pathogenic risk factor for chronic abdominal pain and diarrhea in PCS patients.

[Device and method for evaluating the performance of dry electrode for fabric surface bioelectricity].

In order to quantitatively evaluate the performance of dry electrode for fabric surface bioelectricity, a set of active measuring devices that can simulate electrocardiosignal has been developed on the basis of passive system by our group. Five Ag/AgCl fabric dry electrodes were selected to test and evaluate the devices. The results show that the deviation ratios of peak time interval of the five electrodes are all less than 1%. The maximum voltage amplitude decay rate is 7.2%, and the noise amplitudes are lower than 0.004 mV. The variable coefficient of peak time offset is less than 8%. The variable coefficient of voltage amplitude is less than 2%. The variable coefficient of noise amplitude is less than 10%. Research shows the devices has good repeatability and stability in measuring the simulated electrocardiosignal. The active measuring devices proposed in this paper can provide a new method for performance evaluation and standard formulation of surface bioelectricity dry electrode.