Role of compositional changes on thermal,magnetic,and mechanical properties of Fe-P-C-based amorphous alloys

This work aimed to tune the comprehensive properties of Fe-P-C-based amorphous system through investigating the role of microalloying process on the crystallization behavior,glass forming ability(GFA),soft magnetic features,and mechanical properties.Considering minor addition of elements into the system,it was found that the simultaneous microalloying of Ni and Co leads to the highest GFA,which was due to the optimization of compositional heterogeneity and creation of near-eutectic composition.Moreover,the FeCoNiCuPC amorphous alloy exhibited the best anelastic/viscoplastic behavior under the nanoindentation test,which was owing to the intensified structural fluctuations in the system.However,the improved plasticity by the extra Cu addition comes at the expense of magnetic properties,so that the saturation magnetization of this alloying system is significantly decreased compared to the FeCoPC amorphous alloy with the highest soft magnetic properties.In total,the results indicated that a combination of added elemental constitutes,i.e.,Fe69Co5Ni5Cu1P13C7 composition,provides an optimized state for the comprehensive properties in the alloying system.     

Novel Multifunctional Ascorbic Triazole Derivatives for Amyloidogenic Pathway Inhibition,Anti-Inflammation,and Neuroprotection

Alzheimer’s disease (AD) is a common neurodegenerative disorder. The number of patients with AD is projected to reach 152 million by 2050. Donepezil, rivastigmine, galantamine, and memantine are the only four drugs currently approved by the United States Food and Drug Administration for AD treatment. However, these drugs can only alleviate AD symptoms. Thus, this research focuses on the discovery of novel lead compounds that possess multitarget regulation of AD etiopathology relating to amyloid cascade. The ascorbic acid structure has been designated as a core functional domain due to several characteristics, including antioxidant activities, amyloid aggregation inhibition, and the ability to be transported to the brain and neurons. Multifunctional ascorbic derivatives were synthesized by copper (I)-catalyzed azide–alkyne cycloaddition reaction (click chemistry). The in vitro and cell-based assays showed that compounds 2c and 5c exhibited prominent multifunctional activities as beta-secretase 1 inhibitors, amyloid aggregation inhibitors, and antioxidant, neuroprotectant, and anti-inflammatory agents. Significant changes in activities promoting neuroprotection and anti-inflammation were observed at a considerably low concentration at a nanomolar level. Moreover, an in silico study showed that compounds 2c and 5c were capable of being permeated across the blood–brain barrier by sodium-dependent vitamin C transporter-2.     

Potential Anti-Alzheimer Agents from Guanidinyl Tryptophan Derivatives with Activities of Membrane Adhesion and Conformational Transition Inhibitions

Guanidinyl tryptophan derivatives TGN1, TGN2, TGN3, and TGN4 were synthesized, and these compounds were shown to possess in vitro inhibitory activity for amyloid aggregation in a previous study. Nevertheless, the influence of the TGN series of compounds on the binding and permeation behaviors of an Aβ monomer to the cell membranes was not elucidated. In this study, we investigated the effect of compounds in the TGN series on the behavior of an Aβ monomer regarding its toxicity toward the bilayer lipid membrane using molecular dynamics (MD) simulation. MD simulations suggest that TGN4 is a potential agent that can interfere with the movement of the Aβ monomer into the membrane. The MM-GBSA result demonstrated that TGN4 exhibits the highest affinity to the Aβ_1–42 monomer but has the lowest affinity to the bilayer. Moreover, TGN4 also contributes to a decrease in the binding affinity between the Aβ_1–42 monomer and the POPC membrane. Regarding the results of the binding mode and conformational analyses, a high number of amino-acid residues were shown to provide the binding interactions between TGN4 and the Aβ_1–42 monomer. TGN4 also reduces the conformational transition of the Aβ_1–42 monomer by means of interacting with the monomer. The present study presents molecular-level insights into how the TGN series of compounds affect the membrane adsorption and the conformational transition of the Aβ_1–42 monomer, which could be valuable for the further development of new anti-Alzheimer agents.     

Protein-Protein Interactions: Insight from Molecular Dynamics Simulations and Nanoparticle Tracking Analysis

Protein-protein interaction plays an essential role in almost all cellular processes and biological functions. Coupling molecular dynamics (MD) simulations and nanoparticle tracking analysis (NTA) assay offered a simple, rapid, and direct approach in monitoring the protein-protein binding process and predicting the binding affinity. Our case study of designed ankyrin repeats proteins (DARPins)—AnkGAG1D4 and the single point mutated AnkGAG1D4-Y56A for HIV-1 capsid protein (CA) were investigated. As reported, AnkGAG1D4 bound with CA for inhibitory activity; however, it lost its inhibitory strength when tyrosine at residue 56 AnkGAG1D4, the most key residue was replaced by alanine (AnkGAG1D4-Y56A). Through NTA, the binding of DARPins and CA was measured by monitoring the increment of the hydrodynamic radius of the AnkGAG1D4-gold conjugated nanoparticles (AnkGAG1D4-GNP) and AnkGAG1D4-Y56A-GNP upon interaction with CA in buffer solution. The size of the AnkGAG1D4-GNP increased when it interacted with CA but not AnkGAG1D4-Y56A-GNP. In addition, a much higher binding free energy (∆GB) of AnkGAG1D4-Y56A (−31 kcal/mol) obtained from MD further suggested affinity for CA completely reduced compared to AnkGAG1D4 (−60 kcal/mol). The possible mechanism of the protein-protein binding was explored in detail by decomposing the binding free energy for crucial residues identification and hydrogen bond analysis.     

Curcumin-sensitized TiO2 for enhanced photodegradation of dyes under visible light

Curcumin was coated on P25 TiO₂ by using impregnation method from freshly prepared curcumin solution. The resulting products (Cur–TiO₂–P25) was studied by several techniques such as X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier-transformed infrared spectroscopy, specific surface area by the Brunauer–Emmett–Teller method, and UV–Vis diffused reflectance spectroscopy. Experimental results revealed that impregnation of curcumin at 0.5, 3, 5, and 7 wt% did not affect the native phase of anatase and rutile in P25 significantly, however, it caused red shift of absorption onset in all curcumin-coated samples. The Cur–TiO₂–P25 showed enhanced adsorption efficiency and increased photocatalytic activity under visible light with optimal result at 5 wt% curcumin content. Commercial anatase and rutile coated with curcumin (Cur–TiO₂–an and Cur–TiO₂–ru) were also prepared by the same method for the use in comparative studies of photodegradation of dyes. Cur–TiO₂–an and Cur–TiO₂–ru were also characterized with some selected equipment above but not as extensively as the Cur–TiO₂–P25. Curcumin coating helped improve photocatalytic efficiencies of P25 and anatase but not for rutile. The mechanism of photocatalytic reaction was proposed that under visible light irradiation, curcumin molecule could act as dye sensitizing agent that injected electron into the conduction band of TiO₂ leading to photodegradation of dyes.     

Amorphous titanium dioxide: a recyclable dye remover for water treatment

Decolorization of dye solutions, crystal violet and congo red, were investigated using the synthesized amorphous titanium dioxide and compared with commercial titanium dioxides: Degussa P25 and anatase. Results showed that amorphous TiO₂ had good adsorptivity that could decolorize the dye polluted water effectively mainly by adsorption. Decolorization by photocatalytic property was also detected but was very low. Concentrations of dye solutions used in this work were about ten times higher than normally used in other reports. After use, the particle surface was completely covered with dye molecules but this could be regenerated and the cleaned particles could be reused several times. Hydrogen peroxide and ultraviolet irradiation were used in the regeneration process.     

Biological activities of Peristrophe bivalvis extracts: promising potential for anti-snake venoms against Naja kaouthia and Trimeresurus albolabris venoms

This study evaluates the in vitro anti-snake venom potential of Peristrophe bivalvis (PB) extracts against Naja kaouthia (NK) and Trimeresurus albolabris (TA) venoms, including inhibition of cytotoxic effects and enzymatic activities, and the binding-precipitation of extracts and venom proteins analysis. In addition, the antioxidant, cytotoxic and in vivo acute oral toxic activities of PB extracts are also reported. The in vitro cytotoxic and enzymatic analysis reveals that the ethanol extracts of stems and leaves of PB showed good anti-snake venom activity against NK and TA venoms. In addition, the antioxidant result indicated that only the ethanol extract of leaves exhibited weak DPPH radical-scavenging activity. The ethanol whole-plant extract of PB also showed no cytotoxicity against four cell lines. Moreover, the in vivo acute oral toxicity result of the ethanol whole-plant extract showed that all treated rats did not exhibit abnormal toxic signs or deaths.