Molecules最新文献

The formation of ordered structures by Janus-like particles, composed of two parts (A and B), with orientation-dependent interactions on a triangular lattice was studied using Monte Carlo methods. The assumed lattice model allows each particle to take on one of the six orientations. The interaction between the A parts of neighboring particles was assumed to be attractive, while the AB and BB interactions were assumed to be repulsive. Moreover, it was assumed that the interaction between a pair of neighboring particles depended on the degrees to which their AA, AB, and BB parts face each other. It was shown that several ordered phases of different densities and structures may appear, depending on the magnitudes of AB and BB interactions. In particular, we found several structures composed of small clusters consisting of three (OT), four (OR), and seven (S) particles, surrounded by empty sites, the lamellar phases (OL, OL1, and OL3), the structures with hexagonal symmetry (R3×3 and K), as well as the structures with more complex symmetry (R5×5 and LAD). Several phase diagrams were evaluated, which demonstrated that the stability regions of different ordered phases are primarily determined by the strengths of repulsive AB and BB interactions.

Berberine hydrochloride (BH) extracted from Coptis chinensis (CC) and Matrine (MT) separated from Sophora flavescens (SF) are alkaloids with potent anti-bacterial, anti-inflammatory, and anti-tumor effects. Motivated by the clinical practice of using CC and SF together, we aimed to demonstrate that the synergistic application of the natural compounds BH and MT could enhance therapeutic effects and minimize side effects. Two types of liposomes, liposomes containing only BH (BH-LP) and liposomes containing both BH and MT (BH-MT-LP), were successfully prepared via the reverse evaporation method. The liposome preparation process was optimized by single-factor screening and the Box-Behnken experimental design method. The results showed that the liposomes had particle sizes in the range of 222.7 to 235.4 nm, polydispersity indicated in the range of 11.8% to 23.3%, and zeta potentials in the range of -35.9 to -31.1 mv. BH-MT-LP showed superior anti-tumor activity against MDA-MB-231, HepG-2, and HGC-27 cells in vitro. The incorporation of MT effectively promoted the anti-tumor effect of BH, while the controlled release from liposomes further enhanced the therapeutic efficacy of BH. Furthermore, based on the flow cytometry results, we speculated that BH-MT-LP might promote apoptosis by blocking the G1 phase of cells and inducing cell death. In conclusion, BH-MT-LP provides evidence for the combined use of natural compounds as a stable, safe, and practical drug delivery system for the treatment of potential cancers. Meanwhile, the successful preparation for BH-MT-LP also provides a new approach to the combined use of traditional Chinese medicine ingredients.

In recent years, π-conjugated liquid crystalline molecules with optoelectronic functionalities have garnered considerable attention, and integrating these molecules into side-chain liquid crystalline polymers (SCLCPs) holds potential for developing devices that are operational near room temperature. However, it is difficult to design SCLCPs with excellent processability because liquid crystalline mesogens are rigid rods, have low solubility in organic solvents, and have a high isotropization temperature. Recently, we developed near-room-temperature π-conjugated nematic liquid crystals based on "bridged stilbene". In this work, we synthesized a polyacrylate SCLCP incorporating a bridged stilbene that exhibited a nematic phase near room temperature and could maintain liquid crystallinity for more than three months. We conducted a thorough phase structure analysis and evaluated the optical properties. The birefringence values of the resulting polymers were higher than those of the corresponding monomers because of the enhanced order parameters due to the polymer effect. In addition, the synthesized polymers inherited mesogen-derived AIE properties, with high quantum yields (Φ_fl = 0.14-0.35) in the solid state. It is noteworthy that the maximum fluorescence wavelength exhibited a redshift of greater than 27 nm as a consequence of film formation. Thus, several unique characteristics of the SCLCPs are unattainable with small molecular systems.

Viruses play a significant role in human health, as they can cause a wide range of diseases, from mild illnesses to severe and life-threatening conditions. Cellular and animal experiments have demonstrated that the functional components in tea, such as catechins, theaflavins, theanine, and caffeine, exhibit significant inhibitory effects on a diverse array of viruses, including influenza, rotavirus, hepatitis, HPV, and additional types. The inhibition mechanisms may involve blocking virus-host recognition, interfering with viral replication, enhancing host immune responses, and inhibiting viral enzyme activity. This article reviews the research progress on the antiviral effects of tea's functional components and their related mechanisms, hoping to contribute to future studies in this field.

Lycopene is a natural carotenoid with well-known benefits due to its antioxidant properties, including an anti-inflammatory effect in colorectal cancer and anti-angiogenic effects along with a reduction in the risk of prostate cancer and coronary heart disease. Due to their poor water solubility, photosensitivity and heat sensitivity, their incorporation in cosmetic and food matrices should be through encapsulation systems. In the present work, lycopene-loaded emulsions were prepared using two different types of stabilizers: non-ionic surfactants, testing several ratios of Tween 80 and Span 80, and chitosan, using chitosans of different viscosities and molecular weights. Soybean oil was found to be a suitable candidate for O/W emulsion preparation. Lycopene encapsulation efficiency (EE) of 70-75% and loading capacities of 0.14 mg/g were registered in stable emulsions stabilized either by non-ionic surfactants or acidified chitosans. Therefore, chitosan is a good alternative as a sustainable stabilizer to partially replace traditional synthetic ingredients with a new biodegradable, renewable and biocompatible material which could contribute to reduce the environmental impact as well as the ingestion of synthetic toxic materials by humans, decreasing their risk of suffering from chronic and complex pathologies, among which several types of cancer stand out.

Two-dimensional (2D) transition metal dichalcogenides (TMDs) have recently become attractive candidate substrates for surface-enhanced Raman spectroscopy (SERS) owing to their atomically flat surfaces and adjustable electronic properties. Herein, large-scale 2D 1T'- and 2H-MoTe₂ films were prepared using a chemical vapor deposition method. We found that phase structure plays an important role in the enhancement of the SERS performances of MoTe₂ films. 1T'-MoTe₂ films showed a strong SERS effect with a detection limit of 1 × 10^-9 M for the R6G molecule, which is one order of magnitude lower than that of 2H-MoTe₂ films. We demonstrated that the SERS sensitivity of MoTe₂ films is derived from the efficient photoinduced charge transfer process between MoTe₂ and adsorbed molecules. Moreover, a prohibited fish drug could be detected by using 1T'-MoTe₂ films as SERS substrates. Our study paves the way to the development and application of high-performance SERS substrates based on TMD phase engineering.

Metal ion intercalation into van der Waals gaps of layered materials is vital for large-scale electrochemical energy storage. Transition-metal sulfides, ABS₄ (where A and B represent Zr, Hf, and Ti as monolayers as anodes), are examined as lithium and sodium ion storage. Our study reveals that these monolayers offer exceptional performance for ion storage. The low diffusion barriers enable efficient lithium bonding and rapid separation while all ABS₄ phases remain semiconducting before lithiation and transition to metallic states, ensuring excellent electrical conductivity. Notably, the monolayers demonstrate impressive ion capacities: 1639, 1202, and 1119 mAh/g for Li-ions, and 1093, 801, and 671 mAh/g for Na-ions in ZrTiS₄, HfTiS₄, and HfZrS₄, respectively. Average voltages are 1.16 V, 0.9 V, and 0.94 V for Li-ions and 1.17 V, 1.02 V, and 0.94 V for Na-ions across these materials. Additionally, low migration energy barriers of 0.231 eV, 0.233 eV, and 0.238 eV for Li and 0.135 eV, 0.136 eV, and 0.147 eV for Na make ABS₄ monolayers highly attractive for battery applications. These findings underscore the potential of monolayer ABS₄ as a superior electrode material, combining high adsorption energy, low diffusion barriers, low voltage, high specific capacity, and outstanding electrical conductivity.

S-scheme Fe₂O₃/g-C₃N₄ heterojunctions were successfully fabricated by the ultrasonic assistance method to remove norfloxacin (NOR) under visible light irradiation. The synthesized catalysts were well studied through various techniques. The obtained Fe₂O₃/g-C₃N₄ heterojunctions exhibited an optimal photocatalytic degradation of 94.7% for NOR, which was 1.67 and 1.28 times higher than using Fe₂O₃ and g-C₃N₄ alone, respectively. In addition, the kinetic constant of NOR removal with Fe₂O₃/g-C₃N₄ composites was about 0.6631 h^-1, and NOR photo-deegradation was still 86.7% after four cycles. The enhanced photocatalytic activity may be mainly attributed to the formation of S-scheme Fe₂O₃/g-C₃N₄ heterojunctions with built-in electric fields, which were beneficial to the separation and transfer of photostimulated charge carriers. Furthermore, a possible photo-degradation mechanism of NOR for S-scheme Fe₂O₃/g-C₃N₄ heterojunctions is described.

This article is a continuation of our previous research on the catalytic capability of a chiral copper complex based on commercially available (S)-2-aminomethylpyrrolidine and 3,5-di-tert-butylsalicylaldehyde with various counter-anions in the asymmetric Henry reaction. Our findings indicate that depending on the type of base used, chiral nitroalcohols with yields up to 98% and ee values up to 77%, as well as β-nitrostyrenes with yields up to 88%, can be produced. Additionally, it has been found that the outcome of the reaction and the catalytic properties of copper (II) complexes (S)-Cu1 and (S)-Cu2 are influenced by the structure of the aldehyde used.

The most fruitful prevention and treatment tools for the COVID-19 pandemic have proven to be vaccines and therapeutic antibodies, which have reduced the spread of the disease to manageable proportions. The search for the most effective antibodies against the widest set of COV-2 variants has required a long time and substantial resources. It would be desirable to have a tool that will enable us to understand the structural basis on which mutants escape at least some of the epitope-bound antibodies, a tool that may substantially reduce the time and resources invested in this effort. In this work, we applied a computational-based tool (employed previously by us to understand COV-2 spike binding to its cognate cell receptor) to the study of the effect of Delta and Omicron mutations on the escape tendencies. Our binding energy predictions agree extremely well with the experimentally observed escape tendencies. They have also allowed us to set forth a structural explanation for the results that could be used for the screening of antibodies. Lastly, our results explain the differences in molecular interactions that govern interaction of the spike variants with the receptor as opposed to those with antibodies.