Mixed Acid Research Articles

Weatherability of soluble lead flow batteries using the electrolytes of Pb(CH3SO3)2 and CH3SO3H/HBF4

An electrolyte of Pb(CH3SO3)2 and CH3SO3H/HBF4 mixed acids is utilized to investigate the cycling performance of soluble lead flow batteries over the range −40 °C–50 °C. The solution containing 1.0 M Pb(CH3SO3)2 + 0.4 M CH3SO3H + 1.6 M HBF4 is optimized as the electrolyte based on its freezing point, conductivity and dynamic viscosity. At low temperature, its charge transfer resistance is lower than that in Pb(CH3SO3)2 + CH3SO3H solution. The side reactions of hydrogen and oxygen evolutions are reduced that is beneficial for the electrodeposition of PbO2 and Pb. At high temperature, the hydrolysis of HBF4 could be inhibited by CH3SO3H. The corrosion current density is reduced to effectively avoid the corrosion and failure of graphite electrodes. The coulombic efficiency of cells is maintained at 87.3 %–95.1 % within the range −40 °C–50 °C. The energy efficiency is higher than 74 %. The soluble lead flow battery exhibits an excellent weatherability.

(Digital Presentation) A Novel Method For Molybdenum Etching Using a Combination of Surface Oxidation By Ozone-Gas-Bake and Wet Selective Removal for Future Semiconductor Devices

1. IntroductionAlternative metals are being researched to mitigate the resistivity of the metal wiring at 3 nm technology node and beyond. A performance index or figure of merit (FOM) calculated by multiplying the resistivity and the electron mean free path of the bulk metal has been defined to allow the selection of candidate metals to reduce the resistance of fine wiring. Mo (6.0) is a good candidate compared to the conventional metals such as Cu (6.7) and W (8.2) [1-3]. Commodity wet chemistries, e.g. SC-1 or mixed acids like, Phosphoric:Acetic:Nitric-acid (PAN) are not suitable for wet recess etch of Mo since they increase its surface roughness too much. The model for the increase in roughness has been reported to be due to the presence of grain boundaries on the Mo surface, where preferential "oxidation-dissolution" reactions occur simultaneously in the chemical solution [4,5]. To minimize the roughness, a new cyclic process of dry oxidation and wet etching is developed so that oxidation and etching reactions are separated. In the oxidation step, a homogeneous oxide layer is formed by baking in ozone (O3) gas, then it is selectively etched by subsequent wet chemistry which doesn’t contain any oxidant [6]. In this paper, we report the development of this molybdenum recess process with a higher baking temperature to increase the recess depths, targeting application of buried power rail in logic and word line recess in 3D NAND memory.2. ExperimentalSample: 50 nm Mo films were deposited by Plasma Vapor Deposition on a 100 nm SiO2 film. After metal deposition, the wafers were annealed for 20 minutes at 420°C in pure N2 gas.Etching process: oxidation process is performed in an O3 gas chamber on a single wafer cleaning tool. Bake plate in the O3 gas chamber was heated to 180-290°C. O3 concentration was 100 g/m3 and gas flow rate was 18 L/min. The subsequent wet etch process was performed in wet process chamber on the same tool. 29% NH4OH was mixed with ultrapure water in a 1:8 or 1:100 volume ratio at RT or 70°C.Characterization: the recess amounts of metallic Mo and MoOx thicknesses were measured by sheet resistance measurements and mass measurements of 300 mm wafers. Roughness was measured by Atomic Force Microscope, XSEM was used to validate the above. The polycrystallinity of MoOx was analyzed by Grazing Incidence X-ray Diffraction.3. Results/DiscussionMo thickness decreases as the number of oxidation and etching cycles increases, and the recess amount per cycle was 6 nm at 290°C (Fig. 1). The recess amount per 3 cycles increased as bake temperature increases (Fig. 2). Rq increased from 0.4 nm to 2.8 nm at bake temperatures ≥ 250°C (Fig. 3). XSEM showed that the cause of the surface roughness is residual MoOx (Fig. 4). XRD showed that the MoOx changes significantly at bake temperatures ≥ 250°C since other than the metallic crystalline Mo peak at 2θ = 40° were detected, which suggests that polycrystalline MoOx is formed at high temperature (Fig. 5). The formation of a polycrystalline MoOx could be the cause of the surface roughness because these MoOx are tough to dissolve and therefore the surface would not be recessed evenly. On the other hand, the residual MoOx was etched by NH4OH in a 1:8 ratio at 70°C and Rq was reduced to 0.38 nm after a cyclic process using a 290°C bake with O3 (Fig. 3, 4).4. ConclusionA novel etching method using a combination of “ozone-gas-bake” and “wet selective removal” was developed to overcome the roughness increase during etching of Mo observed with commodity wet chemistries. This method demonstrates good controllability of Mo etching amount by changing the number of cycles without roughening the surface. The surface roughness increased at bake temperatures ≥ 250°C due to the formation of polycrystalline MoOx that could not be removed with the conventional NH4OH solution, but this was mitigated by increasing the temperature of the subsequent NH4OH oxide dissolution step. This new process is expected to be used to recess Mo in logic and memory devices for next generation applications.

Spatial Variations of pH in Electrodialysis Stacks: Theory

Electrodialysis (ED) is a well-known electrochemical water desalination technology investigated since the 1950s. In an ED stack, desalination is driven by an applied voltage, which results in selective salt ion electromigration through alternating cation and anion exchange membranes. Transport of hydronium and hydroxide ions during water treatment, together with water dissociation, can lead to unfavorable product acidity or alkalinity, compromise the membrane charge, or enhance scaling. Conversely, pH deviations can also be leveraged to tune the speciation of weak acid/base electrolytes to enhance chlorine disinfectant efficiency, or facilitate electrostatic removal of contaminants with pH-dependent properties. Thus, it is important to understand the effect of varying feedwater salinity and other system parameters on spatial pH deviations in the vicinity of the membrane, and on the pH of the product water.In this work, we extend ED theory to include pH effects in a repeating unit operated in the underlimiting current regime. Different from the single ion exchange membrane repeating unit considered by Sonin and Probstein [1], which is not applicable for systems including pH effects, we solve the concentration profiles of both the salt and water ions in a full repeating unit comprised of a cation exchange membrane and anion exchange membrane pair. To the first time to our knowledge, our model domain encompasses the entire ED repeating unit without assuming prescribed stagnant layer thickness in which the water dissociation reaction occurs. We solve the Nernst-Planck and electroneutrality set of equations in the channels and non-ideal IEMs, following the approach utilized for capturing pH effects in membrane capacitive deionization [2,3] and reverse osmosis [4,5]. We presented results showing fundamental features, including the concentration and pH distribution in the diluate channel, local flux density across the IEMs, and effluent salinity and pH. Our model predicts that including or excluding pH effects lead to essentially identical predictions for salt fluxes across the IEMs, and thus previous models neglecting pH effects are likely accurately predicting desalination. We also show that reducing salinity augments pH perturbations, but that the effluent pH, which consists of mixed acid and alkaline boundary layers at the diluate channel outlet, does not deviate from inlet neutral pH significantly. In the future, this model framework here can be extended to include multi-ionic solution and species with pH-dependent properties, and validated with a dedicated set of experimental results.

Effects of Different Fatty Acids as Surfactants on the Rheological Properties of Kerosene-Based Magnetic Fluids

Three types of surfactants (oleic acid, linoleic acid, and a mixture of oleic acid and linoleic acid) were coated on ferromagnetic particles, which were dispersed in kerosene to prepare magnetic fluids, to study the effect of different fatty acids as surfactants on the rheological properties of magnetic fluids. The particles were analyzed by XRD, TEM, FT-IR, and VSM. Furthermore, a rheometer was used to examine the rheological properties of kerosene-based magnetic fluids dispersed with various surfactants. The yield stress at different magnetic fields was calculated by fitting the Herschel–Bulkley model. The fitted curve and the observed values of mixed fatty acids are identical. The graphs of viscosity increase with the shear rate for each magnetic fluid were measured at constant magnetic field strengths. At constant shear rates, the curves of viscosity increase with magnetic field intensity were measured. In the absence of a magnetic field, the relative change in viscosity from 40°C to 0°C was observed. The rheological measurements of the mixed fatty acid-dispersed ferrofluid with a rising magnetic field at a constant shear rate are smoother than the single-fatty-acid-dispersed ferrofluid, indicating that it is more stable. As the temperature is dropped, the viscosity–temperature curve evidence that mixed fatty acids as surfactants can lower the proportion of magnetic fluid viscosity rise.

V-Containing Heteropoly Acids with Keggin Structure as Precursors of Sulfide Catalysts: Regularities of the Convertion of Dibenzothiophene and Naphthalene on Nonpromoted Mo–V Catalysts

Mixed PMoV heteropoly acids with Keggin structures H3+xPMo12–xVxO40 (x = 1–6) and modified sulfide catalysts on their basis were synthesized, their physicochemical characteristics were determined, and their performance in the reactions of hydrodesulfurization (HDS) of dibenzothiophene (DBT) and hydrogenation of naphthalene was evaluated. Modification of the Mo-containing catalysts with vanadium by impregnation with a solution of mixed heteropoly acids was found to enhance their catalytic activity in the studied reactions, as well as to increase the selectivity for the direct hydrodesulfurization route of the DBT HDS reaction.

Auto brewery syndrome

Auto brewery syndrome is also known as intestinal fermentation syndrome in which ethanol is produced through engogenous fermentation of fungi or bacteria in gastro-intestinal system, oral cavity or into urinary tract system. It is a rare medical condition which intoxicating quantities of ethanol are produced by endogenous fermentation in the digestive system. The organism responsible for auto brewery syndrome and it includes various organisms yeast and bacteria including including Saccharomyces Cerevisiae, Saccharamyces Boulardii, Candida Albicans, Candida tropical is, Candida Krusei, Candida Glabrata, Candida KEFYR, Candida Parapsilosis, Klebsiella pneumonia and Enterococcus fascism. These organisms use lactic acid fermentation or mixed acid fermentation pathways.

Selective flotation separation of smithsonite from dolomite by using sodium hexametaphosphate as a depressant

In this study, a depressant sodium hexametaphosphate (SHMP) was introduced for the flotation separation of smithsonite from dolomite using mixed benzohydroxamic acid (BHA) and sodium oleate (NaOL) as the collectors. Micro-flotation experiments were conducted to investigate the flotation behavior of smithsonite and dolomite in the absence and presence of SHMP. Furthermore, the depression mechanism of the SHMP was unraveled by Fourier transform infrared (FTIR), X-ray photoelectron spectroscopy (XPS) analysis, and flotation solution chemistry. The flotation results showed that the recovery of dolomite decreased from 26.63% to 2.25% when the addition of SHMP in the flotation system increased from 0 to 50 g/t, while the smithsonite recovery exhibited a slight increase from 91.05% to 93.10%, which improved the separation effect greatly. FTIR measurements and XPS analysis revealed that the SHMP was chemically adsorbed on the dolomite surface in the form of hydrophilic complexes with Ca2+ and Mg2+, thus depressing adsorption of the mixed BHA/NaOL. Flotation solution chemistry analysis suggested that Zn2+ could form ZnCO3 on the surface of the dolomite leading to the transformation of the dolomite surface to the smithsonite surface. And SHMP could form hydrophilic complexes with Ca and Mg sites on the dolomite surface, thus depressing the adsorption of BHA/NaOL on the transformed dolomite surface.

Growth and yield of some promising Egyptian rice genotypes under foliar application of different stimulating compounds

The Effects of foliar application of different stimulating compounds on the growth and yield of three promising Egyptian rice genotypes were studied in a field experiments at the Experimental Farm of Rice Research and Training Center (RRTC), Egypt, during consecutive rice seasons 2018 and 2019. Three rice Egyptian genotypes (Sakha108, GZ9399, and GZ10154) were tested under different stimulating compounds like Ascobine (13% citric acid, 25% ascorbic acid plus 62% organic materials), humic acid (65% humic acid +10% K2O), Amino acid (27.38 % mixed amino acid + 9% micronutrients + 2% magnesium), vulvic acid (50% Vulvic acid + 20% organic acid), N:P:K::20:20:20 and potassium sulphate (50% K2O) The growth characteristics like number of tillers, chlorophyll content, leaf area and dry matter accumulation at 30 and 45 days after transplanting were determined . Number of panicles m-2, panicle length, panicle weight, 1000-grain weight, number of filled grains per panicle, number of unfilled grains per panicle, grain yield and straw yield were studied at harvest. There were significant variations among the studied genotypes in terms of the studied characteristics like (chlorophyll content and grain yield). The foliar application of stimulating compounds significantly increased growth, yield and yield components of the studied rice genotypes. There were significant differences among the response of the studied genotypes to the application of the stimulating compounds. Application of amino acid to Sakha108 recorded the highest grain yield.

Grape‐clustered polyaniline grafted with carbon nanotube woven film as a flexible electrode material for supercapacitors

AbstractThe continuously reinforced carbon nanotube woven film (CNWF) prepared via the floating catalytic chemical vapor deposition (FCCVD) was modified by mixed acid and vinyltrimethoxysilane (VTMS) respectively to obtain carbon nanotube woven film (CNWF@VTMS) grafted with CH2CH group. A series of novel self‐supporting composite electrode materials (CNWF@VTMS/PANI) for supercapacitors were then prepared by in‐situ chemical oxidative polymerization of aniline in the presence of the CNWF@VTMS film substrate as a conductive network framework. The results showed that CNWF@VTMS/PANI14 flexible electrode with grape‐clustered structure exhibited the highest specific capacitance of 531.3 F/g and the highest energy density of 26.5 Wh/kg at the current density of 1 A/g. It could maintain 75.1% of the initial value at a high current density of 10 A/g. The excellent electrochemical cycle and the structural stability have been confirmed on the condition of the higher capacitance retention of 96.6% after 2000 times of galvanostatic charge/discharge, and the almost unchanged electrochemical performances after 300 times of bending and twisting. Meanwhile, the stronger interfacial bonding between CNWF and PANI endowed a higher tensile strength of 129.2 MPa. In this article, CNWF@VTMS/PANI14 composite electrode could be a potential application in the field of deformable supercapacitors.

Reverse anionic flotation of dolomitic collophanite using a mixed fatty acid collector: Adsorption behavior and mechanism

Reverse anionic flotation of dolomitic collophanite using a mixed fatty acid collector: Adsorption behavior and mechanism

High-Precision Magnetic Field Sensor Based on Fiber Bragg Grating and Dual-Loop Optoelectronic Oscillator

A novel fiber-optic magnetic field sensor with high interrogation speed and resolution by using an etched fiber Bragg grating (FBG) in conjunction with a dual-loop optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. A commercial FBG is firstly dipped into mixed hydrofluoric acid solution to remove the cladding layer and then is embedded with the magnetic fluid (MF) as a sensing element. The central wavelength reflected from the FBG is related to the overall time delay of the dual-loop OEO, which determines the oscillating frequency of the OEO. Therefore, the magnetic field can be estimated by measuring the oscillating frequency shift of OEO. The experimental results show that the oscillating frequency linearly increases with the increment of the magnetic field, achieving the sensitivity of 16.3 Hz/Oe with a R-square of 0.991 in the range of 5 mT–10 mT. In addition, the maximum error is within ±0.05 mT in the range of 7 mT–8 mT, which offers potentials in many fields where the high-precision magnetic field measurement is required.

Desensitization effect of chemically induced coal components at room temperature: An experimental study

This study was conducted to address the rock burst problem caused by serious stress concentrations in coal seams. Based on the principle of inducing agent corrosion affecting coal components to soften coal, different inducers were selected to study the desensitization effect of acid leaching induction on coal components. The microscopic behavior characteristics of coal under acid leaching were analyzed, and the qualitative and quantitative laws were obtained for different acid leaching times and microscopic behavior characteristics. The results show the following: (1) The mixed acid solution as an inducer has the effect of immersion, dissolution, and fracture on coal. During the reaction process, the internal pores of the coal expand, and the height of the external liquid decreases. The mixed acid solution had the best effect in terms of the removal of minerals in coal. (2) Under microscopic conditions, the internal crack width of the coal body expanded several times after mixed acid soaking; the difference in the unevenness before and after compression fracture was stable at 25–27%, and the mixed acid expanded the gap in the coal. (3) This practical study shows that the characterization changes of the mixed acid solution, injected into the borehole, combines the characteristics of the citric acid and phosphoric acid solution. The minerals around the borehole are dissolved, and the debris fuses with the solution. The liquid is viscous and forms a film on the surface of the solution. The mixed acid has a more obvious effect on the immersion and dissolution of coal.

季铵化介孔碳纳米球的合成及其在体内协同光热抗菌治疗

<p indent="0mm">Photothermal antimicrobial therapy (PTT) has more advantages than traditional antimicrobial therapy. Photothermal conversion nanomaterials can convert optical energy into thermal energy for killing bacteria under near-infrared light. Compared with antibiotic therapy, PTT has several advantages, such as broad-spectrum antimicrobial performance, spatiotemporal specificity, minimally invasive, and deep tissue penetration, and does not cause bacterial resistance. Nevertheless, the therapeutic effect of PTT monotherapy is not ideal because it is often accompanied by side effects, such as thermal injury. To overcome this shortcoming, synergistic photothermal therapy has attracted extensive research interests. This study first synthesized mesoporous carbon nanospheres (MCNs) with commendable solar-thermal conversion performance and uniform size. Then, carboxy-rich MCNs (CMCNs) were obtained by heating in a mixed acid solution. Subsequently, polyethyleneimine (PEI) was covalently grafted onto the surface of CMCNs using the 1-ethyl-3-(3-dimethyl aminopropyl)-carbodiimide (EDC) and N-hydroxysuccinimide (NHS) coupling reaction. Finally, quaternized mesoporous carbon nanospheres (CMCN-QAC) was obtained using a quaternization reaction. The morphology and crystalline forms of MCNs were analyzed using scanning electron microscopy and X-ray diffraction. The photothermal conversion performance of CMCNs was evaluated using an infrared thermal imager. It was found that the photothermal conversion performance of CMCNs was related to the material concentration and the 808-nm near-infrared laser irradiation power intensity. Moreover, photothermal stability experiments were conducted, and the results show that the CMCNs has stable photothermal conversion performance and stability. Next, the spread plate method and live/dead staining experiments were conducted to study the synergistic photothermal antibacterial effect of CMCN-QAC<italic> in vitro</italic>. The MBC value of CMCN-QAC was 60-μg/mL under 1.5-W/cm² 808-nm near infrared (NIR) laser for <sc>10 min.</sc> Finally, to investigate the synergistic photothermal therapy of CMCN-QAC <italic>in vivo</italic>, we established a mouse model of wound infection induced by <italic>Escherichia coli</italic>. The <italic>in vitro</italic> and <italic>in vivo</italic> results showed that the CMCN-QAC+NIR group exhibited the best therapeutic effect and high biocompatibility, indicating that CMCN-QAC has great potential to serve as a novel synergistic photothermal antimicrobial nanomaterial to treat bacterial infections.

Preparation of a zeolite imidazole skeleton-silica hybrid monolithic column for amino acid analysis via capillary electrochromatography.

We developed a novel, convenient and low-cost one-pot strategy for preparing a zeolitic imidazolate framework-8 (ZIF-8)-silica hybrid monolithic column by adding ZIF-8 directly to a polymer solution of the silica matrix. The simulated stationary phase and monolithic column prepared under optimal conditions were characterized using X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis nitrogen physisorption and zeta potential. The results obtained confirmed the successful introduction of ZIF-8 into the silica monolithic column, and the prepared monolithic column exhibited good permeability and physicochemical stability. A capillary electrochromatography method was developed based on a ZIF-8-silica hybrid monolithic column through which 15 mixed amino acids, 4 neutral compounds, 4 nipagin esters and 2 chlorinated fungicides were separated in 14, 5, 7 and 6min, respectively, under optimal conditions. The relative standard deviations retention times and column efficiencies in run-to-run, day-to-day and column-to-column varied in the ranges of 1.90%-2.21%, 2.13%-2.51% and 3.08%-6.65%, respectively, which demonstrated that ZIF-8-silica hybrid monolithic column exhibited satisfactory reproducibility and stability. The incorporation of ZIF-8 into a silica monolithic column is a promising method for preparing novel monolithic columns composed of a metal-organic framework.

Continuous flow nitration of 3-[2-chloro-4-(trifluoromethyl) phenoxy] benzoic acid and its chemical kinetics within droplet-based microreactors

• The synthesis of Acifluorfen by continuous flow nitration was performed within droplet-based microreactor. • The effects of operating parameters were characterized by hydrodynamics and thermodynamics. • The apparent and intrinsic kinetic model was established. Aromatic nitration still faces unmet technical challenges in relation to being heterogeneous and highly exothermic. In this work, a continuous flow aromatic nitration was developed with mixed acid within droplet-based microreactors. The effects of key operating parameters were characterized on the nitration of 3-[2-chloro-4-(trifluoromethyl)phenoxy] benzoic acid. The optimized reaction temperature, M-ratio and N/S were found to be 308 K, 1.6 and 0.57, respectively. Under these conditions, a conversion of 83.03% and selectivity of 79.52% were achieved. The addition of acetic anhydride improved both the solubility of etherate in the organic phase and the absorbability of water produced from the reaction, leading to increase in conversion, however increased by-products accordingly with reduced selectivity. Pseudo-homogeneous kinetics models were developed of apparent and intrinsic reaction rate constant, supporting the second-order reaction assumption. The calculated results based on the kinetics model were found to be in good agreement with the experimental results.

Activated Carbon Tailored by Potassium Hydroxide from Waste Tires as a Supercapacitor Electrode

Hard-carbon materials are considered as the most promising anodes in various energy storage system applications including lithium, sodium, potassium ion batteries and supercapacitors. Given the huge bulk of the waste tires produced by the rapid development of automobile industry, recycling waste tires to generate value-added products is crucially important for the development of a more sustainable world. In this work, we demonstrate how waste tire-derived pyrolytic char can be transformed into activated carbon for supercapacitor electrodes. The process consists of the acidification of the waste tire-derived pyrolytic char with mixed acids (HCl and HF) and the followed activation with KOH. The activated carbon exhibited a hierarchical meso-/micro-porous network with specific surface area 524 m2 g−1. A traditional three-electrode system was used to investigate the electrochemical performances of the activated carbon as a supercapacitor electrode material, which displayed a specific capacitance of ∼408 F g−1 at 0.25 A g−1 in an electrolyte of 6 M KOH, with capacitance retention of up to 97% after 10,000 charge/discharge cycles. This work offers an innovative and simple approach to yield higher performance activated carbon from waste tires for use in energy storage devices.

Enhancement of Corrosion Resistance Properties of Electrodeposited Ni/nano-TiC Composite Layers.

This paper presents novel results on the effects of the dispersion of titanium carbide nanoparticles (50 nm mean diameter) into a nickel-plating electrolyte on the corrosion behavior of the nanocomposite layers obtained. The Ni/nano-TiC layers are compared with pure nickel layers obtained at the same electrodeposition parameters with 60 mA·cm−2 current density and 10 min deposition time. The comparative corrosion performances are investigated using a three-electrode electrochemical cell in a solution (mixed boric acid with lithium hydroxide), which simulates the primary water circuit of pressurized water reactors (PWRs). Open circuit potential measurement and electrochemical impedance spectroscopy were employed as the electrochemical methods, using an electrochemical workstation connected to an electrochemical cell, as well as a PC with software to drive the experimental work. The results clearly revealed enhanced corrosion properties for the Ni/nano-TiC hybrid layers as compared to the pure Ni layers. The significantly improved corrosion behavior can be attributed to the TiC nanoparticles embedded into the Ni matrix, which have the effect of insulating centers at the composite layer/corrosive solution interface.

Methanogenic treatment of dairy product wastewater by thermophilic anaerobic membrane bioreactor: Ammonia inhibition and microbial community

Dairy product wastewater contains high-strength organic matter suitable for anaerobic treatment, but excessive protein degradation may lead to an ammonia inhibition problem. This work studied protein-rich dairy product wastewater treatment in the anaerobic membrane bioreactor. The results showed that a temporary self-detoxification phase of ammonia inhibition from the change of pH buffer system was vital for rapid reactor recovery by substrate dilution. The ammonia washout from the reactor was simulated by a kinetic model. After ammonia inhibition, the relative abundance of syntrophic lactic and propionic acids oxidising bacteria significantly reduced along with fermentative bacteria involved in mixed organic acids production. Nevertheless, the relative abundance of the protein degradation bacteria producing acetic acid and H2/CO2 increased. A potential metabolic process change was proposed by profiling the functional community. To conclude, substrate dilution is essential for overcoming ammonia inhibition in the anaerobic treatment of protein-rich dairy product wastewater.

Visualization of Enantiorecognition and Resolution by Chiral AIEgens.

Enantioselective recognition and separation have attracted much attention in pharmaceutical analysis, food chemistry, and life science. Herein, we propose an efficient strategy to achieve such purposes using optically active luminogens with aggregation-induced emission (AIE) characteristics. These AIE luminogens (AIEgens) show strong enantiomeric discrimination for 12 kinds of chiral acids and unprotected amino acids. In particular, an exceptionally high enantioselectivity for d/l-Boc-glutamic acid was observed, as demonstrated by the large difference between the formed AIEgen/acid complexes. Due to the AIE effect, enantioselective separation was achieved by aggregation of the AIEgens with one enantiomer in the mixed acid solution. Through analysis of the fluorescence standard curve, the aggregates of AIEgen/chiral acid possessed 90% d-analyte, from which the enantiomeric excess (ee) value was assessed to be 80% ee. Such a result is in good agreement with that (91% d-analyte and 82% ee) by chiral HPLC analysis. Thus, this simple one-step aggregation method can serve as a preliminary screening tool for high-throughput analysis or separation of chiral chemicals.

Whey protein concentrate mixed beverages and plasma amino acid response in young males

Whey protein isolate (WPI) and whey protein hydrolysate (WPH) contains more protein than whey protein concentrate. However, to achieve a better taste, most commercial products mix WPI and WPH with whey protein concentrate (WPC). This study aimed to compare postprandial blood amino acids following ingestion of three beverages: WPImixed with WPC (WPI-mixed), WPH-mixed with WPI (WPH-mixed), and placebo. A total of ten healthy men aged between 18 and 30, who regularly engaged in exercise training, were recruited as participants. They each received 350 mL of each beverage on separate days and 6-day apart. Concentrations of plasma essential amino acids (EAA), branched-chain amino acids (BCAA), and leucine (Leu) were measured in blood samples taken from participants every 15 mins for 2 hrs. Plasma concentrations of EAA, BCAA, and Leu increased after ingestion of the WPI-mixed and WPH-mixed beverages versus the placebo beverage (P&lt;0.05). Plasma EAA did not differ between WPI- mixed and WPmixed trials. In contrast, plasma concentrations of BCAA after WPI-mixed were higher than after WPH-mixed at 30 mins. The same was observed for Leu at 30 and 75 mins after ingestion. The higher plasma BCAA and Leu in the WPI-mixed trial versus the WPHmixed trial may have been due to the presence of short-chain peptides, as bioactive peptides, in WPH-mixed, which were absorbed. In conclusion, there was no difference in plasma EAA, but plasma concentrations of leucine and BCAA were higher in the WPImixed trial than WPH-mixed trial. Therefore, future research should investigate bioactive peptides along with plasma amino acids.