Extraction Optimization of Polysaccharides from Pitaya Stems

[Objective]The aim was to describe the extraction of polysaccharides from pitaya stems.[Method]The hot water,enzyme-assisted and microwave-assisted methods were used,with the microwave-assisted extraction being deemed optimal by general evaluation.[Result]The main factors affecting the yield of polysaccharides in the microwave-assisted extraction,by order of magnitude,were as follows:time >microwave power >temperature;additionally,optimal conditions included a 10 min extraction time,an 80℃ extraction temperature and a microwave setting of 200 W.Using these optimal conditions,the yield of PSPS(Polysaccharides from Pitaya Stems) was 1.42%.After purification,the yield of PSPS was 0.74%.[Conclusion]The PSPS was analyzed by IR,MALDI-TOF-MS and an element analysis technique.It was shown to be a polysaccharide mixture,and the molecular weight was between 3 900 and 4 300 Da.

Computational biology in topical bioactive peptide discovery for cosmeceutical application:a concise review

Regenerative medicine and anti-aging research have made great strides at the molecular and cellular levels in dermatology and the medical aesthetic field,targeting potential treatments with skin therapeutic and intervention pathways,which make it possible to develop effective skin regeneration and repair ingredients.With the rapid development of computational biology,bioinformatics as well as artificial intelligence(A.I.),the development of new ingredients for regenerative medicine has been greatly accelerated,and the success rate has been improved.Some application cases have appeared in topical skin regeneration and repair scenarios.This review will briefly introduce the application of bioactive peptides in skin repair and anti-aging as emerging ingredients in cosmeceutics and emphasize how A.I.based computational biology technology may accelerate the development of innovative peptide molecules and ultimately translate them into potential skin regenerative and anti-aging scenarios.Typically,two research routines have been summarized and current limitations as well as directions were discussed for border applications in future research.

Dual-mode emission of single-layered graphene quantum dots in confined nanospace： Anti-counterfeiting and sensor applications

Engineering of the luminescent properties for graphene quantum dots （GQDs） presents two enormous challenges： 1） The bandgap of GQDs is mainly determined by structural defects （size, shape, and the fraction of sp2 and sp3 domains）, which results in non-stoichiometric nature; 2） the preparation methods limit the achievement of an accurate chemical structure of GQDs, leading to many controversial explanations over the relationship between the structural defects and bandgaps. Here, single-layered GQDs with an exact structure are obtained by in-situ reaction of intercalated precursors in the confined nanospace of layered double hydroxides （LDHs）. Subsequently, the structure-property relationship is uncovered, demonstrating the enhanced fluorescence and activated room temperature phosphorescence of the as-pre- pared GQDs-LDHs, which originate from synergistic effects： 1） strong confine- ment provided by the nanospace of LDHs; 2） rich O-containing functional groups on the surface of GQDs resulting from LDH catalysis. Moreover, the colorless nature and dual-emission characteristics of GQDs-LDHs satisfy the preconditions as anti-counterfeiting markers for protecting valuable documents （bank notes, commercial invoices, etc.）. Particularly, owing to the low toxicity of GQDs and the edible property of LDHs, the GQDs-LDHs/gelatin capsules could be the new generation of potential green anti-counterfeiting material in the field of food and drugs.

The impact of solvent and modifier on ZnO thin-film transistors fabricated by sol-gel process

Techniques for fabricating solution-processed zinc oxide(ZnO)-based thin-film transistors(TFTs)are feasible with solution using various routes.Here,ZnO TFTs were fabricated via sol-gel method using zinc acetate as the starting reagent with different modifiers and solvents.The ZnO thin-film semiconductors with well-controlled,preferential crystal orientation and densely packed ZnO crystals can be prepared with the optimized fabrication conditions,exhibiting excellent field-effect far exceeding those of hydrogenated amorphous silicon(a-Si:H).However,the field-effect characteristics of ZnO TFTs were different for different precursor systems which were constituted by zinc acetate,modifiers and solvents.The co-modification of acetoin and monoethanolamine for the precursor system exhibited higher extent of crystal orientation and field-effect.The maximum mobility of 7.65 cm2V-1s-1 and current on-to-off ratio of^105–106 have been obtained.

Fabrication of Zn-Ti layered double hydroxide by varying cationic ratio of Ti^(4+) and its application as UV absorbent

ZnTi-layered double hydroxides（LDHs） with varying Zn/Ti ratio have been synthesized by coprecipitation of zinc and titanium salts from homogeneous solution.The obtained ZnTi-LDHs possess high crystallinity and hierarchical structure with improved UV-absorbance property.The UV-vis spectra show that the UV absorbing properties of ZnTi-LDHs is stronger and broader than both MgAl-LDH and ZnAl-LDH due to the existence of Ti.Moreover,the UV absorption property increased with the content of Ti,which can be ascribed to the decrease in the band gap energy,as clearly confirmed by density functional theory calculations.When irradiated by UV rays,the property of the samples with generated free radicals（OH^·and O2^·） was evaluated by means of electron spin resonance（EPR）.ZnTi-LDHs generated a relatively lower active radicals in contrast with TiO2 and ZnO,which implied an increased safety used as sunscreens.Therefore,this work provides a detailed understanding of UV shielding properties of ZnTiLDHs which was unrevealed previously,and demonstrates the expansive application prospects of ZnTiLDHs in the field of sunscreens.