We systematically summarize the recent progress in the green synthesis and formation mechanism of CDs with the hope to provide guidance for developing CDs with the concept of green chemistry. In addition, we discuss and organize the current opinions on the fluorescence origin of CDs and the latest progress of CDs in fluorescence sensing applications.
As the energy storage ecosystem evolves beyond lithium, MXenes, a versatile family of 2D materials derived from MAX phases, have emerged as promising candidates for next-generation energy storage electrodes due to their tunable surface chemistry, large interlayer spacing, and excellent electronic conductivity. In this work, we use density functional theory to investigate Ti$_3$C$_2$ and V$_2$C MXenes as cathodes in Al-ion batteries. Four stacking configurations of the two-dimensional sheets and two different ion coordination sites are evaluated to understand their influence on ion intercalation and mobility. We find that the stacking configuration and surface chemistry critically impact interlayer spacing and electrochemical performance. O-terminated layers in an octahedral stacking exhibit remarkable structural stability with minimal interlayer expansion upon ion intercalation, particularly for Al intercalation in V$_2$C which exhibits an interlayer expansion of 0.1 angstrom, consistent with experimental findings. While octahedral stacking is observed to be energetically more favourable, it reduces ion mobility compared to prismatic stacking. Furthermore, O-terminated MXenes exhibit high theoretical specific capacities, reaching more than 270 mAh/g. F-terminated MXenes are considerably more unstable after intercalation and as a result exhibit much lower Al capacities. These findings highlight the importance of stacking configurations, termination and intercalant chemistry in MXenes for battery applications.
Bhavika A. Bhavsar, Vaishali Jain, Annu Kumari
et al.
Objective:
To Evaluate The Antimicrobial Properties of Double Antibiotic Paste and Morinda citrifolia And Propolis Paste Used In Regenerative Endodontics.
Materials and Method:
Using intact human teeth, radicular dentin samples were prepared (dimensions 4×4×2 mm) by following a standard method. The samples were cut using a diamond saw at minimal speed using water as coolant and smoothed with abrasive papers. To expose the dentin tubules and eliminate the smear layer, they were treated with NaOCl (1.5%), distilled water, and EDTA (17%). A total of 30 dentin samples went through a three-week anaerobic infection with bacterial biofilms sourced from the root canal of an underdeveloped tooth showing pulp necrosis. Group 1 acted as the control, while Group 2 received treatment with DAP, and Group 3 was treated with a paste of Morinda citrifolia and Propolis. After a week, pastes were cleaned, and specimens were dipped in phosphate-buffered saline for a day. The biofilm was released from each specimen by sonicating and vortexing it for 30 seconds. It was then diluted, spiral-plated on blood agar, and cultured anaerobically for a day. An automated colony counter was utilized to measure colony-forming units (CFU/mL), and statistical analysis was conducted using the Wilcoxon rank-sum test.
Result:
The wash from dentin samples treated with DAP and MCP showed minimal CFU counts, indicating both pastes’ high efficiency against biofilm-forming microbes from the canals of an immature tooth exhibiting pulp necrosis.
Conclusion:
Dentin samples infused with DAP and MCP showed minimal CFU counts, indicating their high effectiveness against biofilm-forming microbes from the root canal of an underdeveloped tooth with pulp necrosis. Additional research is required to validate these findings.
Chukwuma Ogechukwu Bose, Rafatullah Mohd, Kapoor Riti Thapar
et al.
Lignocellulosic biomass, owing to its recalcitrant nature, requires a consortium of enzymes for its breakdown. The present study deals with the isolation of cellulolytic bacterial strains from landfill leachate collected from the Pulau Burung landfill site of Penang, Malaysia, and consortia were constructed to test their cellulolytic efficiency. The dinitro salicylate method was used for the estimation of enzyme activity, and consortia were compared with promising bacterial strains. The combined potential of promising bacterial strains was optimized at varying experimental conditions to detect their maximum cellulolytic activity. The results showed that eight bacterial strains reflected hydrolytic activities, and these were identified by 16S rDNA sequence as Bacillus subtilis, Bacillus pumilus, Bacillus proteolyticus, Bacillus paramycoides, Bacillus cereus, Bacillus altitudinis, Bacillus niacin, and Bacillus thuringiensis. Consortia A included Bacillus proteolyticus, Bacillus subtilis, Bacillus pumilus, and Bacillus paramycoides and reflected high thermophilic inclination as the optimal temperature was 45°C at pH 6 with the highest cellulase activity of 0.90 U/ml. Consortia B included Bacillus cereus, Bacillus altitudinis, Bacillus niacin, and Bacillus thuringiensis and showed a cellulase activity of 0.78 U/ml at 38°C and pH 6. The results reflected the significant potential of these Bacillus strains and consortia in the breakdown of cellulose into useful end products. The consortia further proved that a synergistic relationship was more favourable for bioconversion processes.
Abstract Stem cell differentiation must be regulated by intricate and complex interactions between cells and their surrounding environment, ensuring normal organ and tissue morphology such as the liver1. Though it is well acknowledged that microgravity provides necessary mechanical force signals for cell fate2, how microgravity affects growth, differentiation, and communication is still largely unknown due to the lack of real experimental scenarios and reproducibility tools. Here, Rotating Flat Chamber (RFC) was used to simulate ground-based microgravity effects to study how microgravity effects affect the differentiation of HepaRG (hepatic progenitor cells) cells. Unexpectedly, the results show that RFC conditions could promote HepaRG cell differentiation which exhibited increased expression of Alpha-fetoprotein (AFP), albumin (ALB), and Recombinant Cytokeratin 18 (CK18). Through screening a series of mechanical receptors, the ion channel TRPML1 was critical for promoting the differentiation effect under RFC conditions. Once TRPML1 was activated by stimulated microgravity effects, the concentration of lysosomal calcium ions was increased to activate the Wnt/β-catenin signaling pathway, which finally led to enhanced cell differentiation of HepaRG cells. In addition, the cytoskeleton was remodeled under RFC conditions to influence the expression of PI (3,5) P2, which is the best-known activator of TRPML1. In summary, our findings have established a mechanism by which simulated microgravity promotes the differentiation of HepaRG cells through the TRPML1 signaling pathway, which provides a potential target for the regulation of hepatic stem/progenitor cell differentiation and embryonic liver development under real microgravity conditions.
Atsuki Ishibashi, Germán Molpeceres, Hiroshi Hidaka
et al.
With the advent of JWST ice observations, dedicated studies on the formation reactions of detected molecules are becoming increasingly important. One of the most interesting molecules in interstellar ice is CO$_2$. Despite its simplicity, the main formation reaction considered, CO + OH -> CO$_2$ + H through the energetic HOCO* intermediate on ice dust, is subject to uncertainty because it directly competes with the stabilization of HOCO as a final product which is formed through energy dissipation of HOCO* to the water ice. When energy dissipation to the surface is effective during reaction, HOCO can be a dominant product. In this study, we experimentally demonstrate that the major product of the reaction is indeed not CO$_2$, but rather the highly reactive radical HOCO. The HOCO radical can later evolve into CO$_2$ through H-abstraction reactions, but these reactions compete with addition reactions, leading to the formation of carboxylic acids (R-COOH). Our results highlight the importance of HOCO chemistry and encourage further exploration of the chemistry of this radical.
Tailoring the phase constitutions of the interfacial reaction layers under the assistance of ultrasonic vibration is a convenient method to fabricate high-strength Al/Cu brazing joints. In this study, 1060-Al and T2-Cu dissimilar metals were ultrasonically brazed with Zn-3Al (wt. %) filler metals. Effects of ultrasonic brazing time on the microstructure and mechanical properties of joints were investigated. Results showed that the CuZn5 intermetallic compound (IMC) layer and Cu-based diffusion layer were created on the Cu substrate surface in the joint ultrasonically brazed at 400 ℃ for 2 s. However, the CuZn5 IMC layer was gradually transformed into a thin Al4.2Cu3.2Zn0.7 IMC layer by increasing the ultrasonic vibration time to 15 s. A well-matched coherent interface was formed between the Al4.2Cu3.2Zn0.7 ternary phase and the Cu-based diffusion layer. The phase transition of the Cu-side interfacial layer correlated closely with the acoustic cavitations induced super-saturation regions near the Cu substrate surface. The measured tensile strength of the Al/Zn-3Al/Cu joint ultrasonically brazed for 15 s was 89.3 MPa, which was approximately 2.5 times higher than that brazed for 2 s, and the tensile failure mainly occurred at the interface between the Al4.2Cu3.2Zn0.7 layer and the Cu-based diffusion layer.
Stratified premixed combustion, known for its capability to expand flammability limits and reduce overall-lean combustion instability, has been widely adopted to comply with increasingly stringent environmental regulations. Numerous numerical simulations with different combustion models and mesh resolutions have been conducted on laboratory-scale flames to further understand the stratified premixed combustion. However, the trade-off between the high-fidelity and low computational cost for simulating laboratory-scale flames still remains, particularly for those combustion models involving direct coupling of chemistry and flow. In the present study, a GPU-based solver is employed to solve partial differential equations and calculate the thermal and transport properties, while an artificial neural network (ANN) is introduced to replace reaction rate calculation. Particular emphasis is placed on evaluating the proposed GPU-ANN approach through the large eddy simulation of the Cambridge stratified flame. The simulation results show good agreement for the flow and flame statistics between the GPU-ANN approach and the conventional CPU-based solver with direct integration (DI). The comparison suggests that the GPU-ANN approach can achieve the same level of accuracy as the conventional CPU-DI solver. In addition, the overall speed-up factor for the GPU-ANN approach is over two orders of magnitude. This study lays the potential groundwork for fully resolved laboratory-scale flame simulations based on detailed chemistry with much more affordable computational cost.