Ultrasonic liquid exfoliation for producing graphene materials from rice stem: Investigating cellular components and functionalities.

This study investigates a prospective and straightforward method for producing graphene material derived from biomass, examining the influence of plant cell composition and functions. The experimental outcomes highlight ultrasound's crucial role in synthesizing graphene material sourced from biomass. Ultrasound, a pivotal element in the experiment, significantly affects graphene production from biomass by working synergistically with the liquid components in the solvent system. Notably, the ethanol content reduces the solution's surface tension, facilitating the effective dispersion of biochar and graphene oxide sheets throughout the process. Simultaneously, the water content maintains the solution's polarity, enhancing the cavitation effect induced by ultrasound. Biomass-derived graphene is exfoliated utilizing an ultrasonic bath system (134.4 W, 40 kHz, 0.5 W/cm2) from biochar. The as-synthesized graphene oxide exhibits a structure comprising a few layers while remaining intact, featuring abundant functional groups. Interestingly, the resulting product displays nanopores with an approximate diameter of 100 nm. These nanopores are attributed to preserving specific cell structures, particularly those with specialized cell wall structures or secondary metabolite deposits from biomass resources. The study's findings shed light on the impact of cellular structure on synthesizing graphene material sourced from biomass, emphasizing the potential application of ultrasound as a promising approach in graphene production.

The COVID-19 Vaccines: Recent Development, Challenges and Prospects.

The highly infectious coronavirus disease 2019 (COVID-19) associated with the pathogenic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has spread to become a global pandemic. At present, the world is relying mainly on containment and hygiene-related measures, as well as repurposed drugs to control the outbreak. The development of COVID-19 vaccines is crucial for the world to return to pre-pandemic normalcy, and a collective global effort has been invested into protection against SARS-CoV-2. As of March 2021, thirteen vaccines have been approved for application whilst over 90 vaccine candidates are under clinical trials. This review focuses on the development of COVID-19 vaccines and highlights the efficacy and vaccination reactions of the authorised vaccines. The mechanisms, storage, and dosage specification of vaccine candidates at the advanced stage of development are also critically reviewed together with considerations for potential challenges. Whilst the development of a vaccine is, in general, in its infancy, current progress is promising. However, the world population will have to continue to adapt to the "new normal" and practice social distancing and hygienic measures, at least until effective vaccines are available to the general public.

Carbodiimide coupling versus click chemistry for nanoparticle surface functionalization: A comparative study for the encapsulation of sodium cholate by cellulose nanocrystals modified with ß-cyclodextrin.

Grafting beta-cyclodextrin (ß-CD) onto cellulose nanocrystals (CNC) with the formation of well-dispersed nanoparticles (CNC-CD) and understanding their physicochemical properties are appealing but still challenging in controlled-release applications. Two immobilization methods were proposed and examined in this study; (i) copper (I) catalyzed click chemistry (CuACC) and (ii) carbodiimide coupling. Fourier-transform infrared spectroscopy (FTIR), UV-vis, elementary analysis, contact angle measurements, and thermogravimetric analysis (TGA) were conducted to elucidate the surface modifications. Phenolphthalein (PHTH) titration was used to quantify the grafting efficiency of ß-CD on the CNC surface. The carbodiimide coupling in dimethyl sulfoxide was effective to introduce the highest amounts of ß-CD (0.17 mmol/g sample) to the CNC in this study. The encapsulation process of bile surfactant, sodium cholate (NaC) was investigated by isothermal titration calorimeter (ITC), and the thermodynamic parameters were determined. The "molecular docking" brought by ß-CD offers possible new applications of this sustainable nanohybrid system in the environmental, biomedical and pharmaceutical sectors.

Probiotic Supplements: Hope or Hype?

Probiotic bacteria have been associated with various health benefits and included in overwhelming number of foods. Today, probiotic supplements are consumed with increasing regularity and record a rapidly growing economic value. With billions of heterogeneous populations of probiotics per serving, probiotic supplements contain the largest quantity of probiotics across all functional foods. They often carry antibiotic-resistant determinants that can be transferred to and accumulate in resident bacteria of the gastrointestinal tract and risk their acquisitions by opportunistic pathogens. While the health benefits of probiotics have been widely publicized, this health risk, however, is underrepresented in both scientific studies and public awareness. On the other hand, the human gut presents conditions that are unfavorable for bacteria, including probiotics. It remains uncertain if probiotics from supplements can tolerate acids and bile salts that may undermine their effectiveness in conferring health benefits. Here, we put into perspective the perceived health benefits and the long-term safety of consuming probiotic supplements, specifically bringing intolerance to acids and bile salts, and the long-standing issue of antibiotic-resistant gene transfer into sharp focus. We report that probiotics from supplements examined in this study have poor tolerance to acids and bile salts while also displaying resistance to multiple antibiotics. They could also adapt and gain resistance to streptomycin in vitro. In an environment where consuming supplements is considered a norm, our results and that of others will put in perspective the persisting concerns surrounding probiotic supplements so that the current hype does not overpower the hope.

Characterization of microstructured fibre emitters: in pursuit of improved nano electrospray ionization performance.

Full-dimensional computational fluid dynamics (CFD) simulations are presented for nano electrospray ionization (ESI) with various emitter designs. Our CFD electrohydrodynamic simulations are based on the Taylor-Melcher leaky-dielectric model, and the volume of fluid technique for tracking the fast-changing liquid-gas interface. The numerical method is first validated for a conventional 20 µm inner diameter capillary emitter. The impact of ESI voltage, flow rate, emitter tapering, surface hydrophobicity, and fluid conductivity on the nano-ESI behavior are thoroughly investigated and compared with experiments. Multi-electrospray is further simulated with 2-hole and 3-hole emitters with the latter having a linear or triangular hole arrangement. The simulations predict multi-electrospray behavior in good agreement with laboratory observations.