Elucidation of stabilizing pickering emulsion with jackfruit filum pectin-soy protein nanoparticles obtained by photocatalysis

There is still the dearth of reports of jackfruit filum pectin-based nanoparticles as the Pickering emulsifiers with respect to the applications in foods, cosmetics and medicines. So we fabricated soy protein-jackfruit filum pectin nanoparticles (SPP) by photocatalysis as Pickering emulsifier. Jackfruit filum pectin exhibited lower yield (17.31%), degree of methoxylation (15.53%), but higher galacuronic acid content (74.22%). A strong linkage between pectin and soy protein was formed by photocatalysis. The conjugated polymer could self-assemble into compact near globular nanoparticle. The mean size of SPP was larger than that of soy protein nanoparticles but smaller than that of soy protein-pectin complex without photocatalysis. Besides, the zeta potential of SPP was ?33.8?mV, significantly lower than that of soy protein nanoparticles but higher than that of control sample, further confirming that SPP surfaces were completely covered with pectin molecules. Compared with control sample, the three-phase contact angle increased from 42.7 to 90.6°, indicated that SPP could be developed as effective Pickering emulsifiers. The emulsions stabilized by SPP exhibited high thermal stability and excellent salt tolerance as well as good freeze-thaw stability in comparison with emulsions covered with control sample. These findings would provide a potential way of producing effective Pickering emulsifier.GRAPHICAL ABSTRACT     

Electrochemical Signal Enhancer Fabricated Using Lysine‐rich Peptide for Ultrasensitive Electrochemical DNA Biosensor Analysis

Here we present a novel design of electrochemical signal enhancer to increase the detection sensitivity of electrochemical DNA biosensors. The key element of this enhancer is a lysine‐rich peptide (LRP). Its C‐terminal is conjugated with a planer molecule, being able to intercalate into the base pairs of probe‐target duplexes. The lysine residues of LRP are covalently linked with electrochemical signal indicators, acting as an assembly of electrochemical signal indicators. Experimental results proved the feasibility of the novel design. We have examined the effects of the numbers of lysine residues and the hybridization conditions on the detection sensitivity. The optimization procedures have led to significant sensitivity enhancement, and the LOD (limit of detection) has been determined to be 1.4 amol. This enhancer demonstrates advantages of easy operation, simple instrumentation, and high exemption from environmental influence.     

Pillar[5]arene-based polymeric architectures constructed by orthogonal supramolecular interactions

Ureidopyrimidinone functionalized pillar[5]arene (UPyP5) was synthesized and employed to complex with a bisparaquat derivative (G) to form supramolecular polymers at relatively high concentration. The orthogonal binding interactions including quadruple hydrogen bonding and host-guest interaction should play vital roles in the construction of this linear assembly.     

Dissolution Thermodynamics of 1,2,3-Triazole Nitrate in Water

The enthalpies of dissolution of 1,2,3-triazole nitrate in water were measured using a RD496-2000 Calvet microcalorimeter at four different temperatures under atmospheric pressure. Differential enthalpies (Δ_dif H) and molar enthalpies (Δ_diss H) of dissolution were determined. The corresponding kinetic equations that describe the dissolution rate at the four experimental temperatures are \fracdadt / s ^{- 1} = 10 ^{- 3.75}( 1 - a)^0.96\frac{d\alpha}{dt} / \mathrm{s}^{ - 1} =10^{ - 3.75}( 1 - \alpha)^{0.96} (T=298.15 K), \fracdadt /s ^{- 1} = 10 ^{- 3.73}( 1 - a)^1.00\frac{d\alpha}{dt} /\mathrm{s}^{ - 1} = 10^{ - 3.73}( 1 - \alpha)^{1.00} (T=303.15 K), \fracdadt / s ^{- 1} = 10 ^{- 3.72}( 1 - a)^0.98\frac{d\alpha}{dt} / \mathrm{s}^{ - 1} = 10^{ - 3.72}( 1 - \alpha)^{0.98} (T=308.15 K) and \fracdadt / s ^{- 1} = 10 ^{- 3.71}( 1 -a)^0.97\frac{d\alpha}{dt} / \mathrm{s}^{ - 1} = 10^{ - 3.71}( 1 -\alpha)^{0.97} (T=313.15 K). The determined values of the activation energy E and pre-exponential factor A for the dissolution process are 5.01 kJ⋅mol⁻¹ and 10^−2.87 s⁻¹, respectively.     

Diffusion Mechanism of As‐spun Polyacrylonitrile Fiber in a Dimethyl Sulfoxide‐Water Coagulation Bath

In this paper, the diffusion mechanism of as‐spun PAN fiber was investigated in dimethyl sulfoxide‐water by determining the dynamic compositions of the fibers and the diffusion coefficients of solvent and nonsolvent during coagulation. The diffusion process could be divided into two stages. Results showed that the first stage of the diffusion process was the most important during the whole process, which was fundamental to further study on the formation mechanism. Also, compared with wet spinning, the dry‐jet wet spinning method had the advantage of mild coagulating at a high jet‐stretch. At high concentrations, the diffusion coefficients increased and the ratio of solvent diffusion coefficient to nonsolvent diffusion coefficient decreased; an increasing temperature resulted in the increase of both diffusion coefficients with a decrease in their ratios. To some extent, for the PAN‐DMSO‐water system, the more the ratios D_s*/D_n* tended to 1, the more the cross‐section shapes of as‐spun PAN fiber tended to be circular.     

Synthesis and Characterization of Poly(ether ether ketone)s with (2,5‐dihydroxy)phenyl Side Group

A new monomer, (2,5‐dimethoxy)phenylhydroquinone (DMPH), was prepared in a two‐step synthetic procedure. One aromatic poly(ether ether ketone)s with 2,5‐dimethoxy phenyl side group (DMP‐PEEK) was synthesized via an aromatic nucleophilic substitution reaction with 4,4′‐difluorobenzophenone (DFB). Poly(ether ether ketone)s with 2,5‐dihydroxy phenyl side group (DHP‐PEEK) was obtained via hydrolysis of methoxy group on the DMP‐PEEK. Both of the high molecular weight polymers could be obtained despite the steric effect of the bulky pendant groups. The two polymers have good solubility at room temperature.     

Further Studies on the Anionic Copolymerization of Styrene and Glycidyl Methacrylate in Toluene

Sequential anionic copolymerization of styrene and glycidyl methacrylate (GMA) was performed with the protection of argon under normal pressure, where styrene, GMA, toluene, THF, n-butyllithium and a small amount of lithium chloride (LiCl) were used as first monomer, second monomer, solvent, polar reagent, initiator and additive, respectively. Polystyrene-b-poly(glycidyl methacrylate) diblock copolymers (PS-b-PGMA) with well-defined structure and narrow molecular weight distribution were prepared by the copolymerization reaction of poly(styryl)lithium with GMA under certain temperatures. The copolymers were characterized using gel permeation chromatography (GPC), ¹H-NMR, ¹³C-NMR, thin layer chromatography (TLC) and hydrochloric acid-dioxane argentimetric methods. The effects of additives, copolymerization temperature and THF dosage on the copolymerization were studied. No chain transfer reaction of anionic polymerization of styrene in toluene was observed. Slightly broader molecular weight distribution of PS-b-PGMA was observed with the increase the GMA repeat units. Using THF/toluene blend solvent could reduce the polydispersity index (M _w /M _n ) and dissolve the copolymer better than toluene alone. Lower temperature (< -40°C) and LiCl are required to prepare PS-b-PGMA with narrower molecular weight distribution.     

由聚苯胺粒子组成的电流变液的研究

由经碱处理的掺杂态聚苯胺（ＰＡｎ）制得高介电常数的半导体ＰＡｎ粒子，将其悬浮于电绝缘油可组成电流变液，讨论了电流变（ＥＲ）液的静态屈服应力（τ＿ｓ），电流密度等性能与ＰＡｎ的介电常数（ε＿ｐ），导电率（σ），体积分数和应用电场强度的关系。对导电率相同的ＰＡｎ粒子，用氨水处理的ＰＡｎ粒子ε＿ｐ较用ＮａＯＨ液处理的高，前者在σ足够低如σ≤１．０×１０￣（－７）／ｃｍ时，ＥＲ液的τ＿ｓ随偶极系数的平方（β￣２）的增大而呈现非线性增加；后者ＥＲ液的τ＿ｓ随β￣２的增大出现一最大值．结果表明：由聚苯胺粒子可组成高电流变活性的无水ＥＲ液．     

Effects of a natural prolyl oligopeptidase inhibitor, rosmarinic acid, on lipopolysaccharide-induced acute lung injury in mice

Rosmarinic acid (RA), a polyphenolic phytochemical, is a natural prolyl oligopeptidase inhibitor. In the present study, we found that RA exerted potent anti-inflammatory effects in in vivo models of acute lung injury (ALI) induced by lipopolysaccharide (LPS). Mice were pretreated with RA one hour before challenge with a dose of 0.5 mg/kg LPS. Twenty-four hours after LPS was given, bronchoalveolar lavage fluid (BALF) was obtained to measure pro-inflammatory mediator and total cell counts. RA significantly decreased the production of LPS-induced TNF-a, IL-6, and IL-1β compare with the LPS group. When pretreated with RA (5, 10, or 20 mg/kg) the lung wet-to-dry weight (W/D) ratio of the lung tissue and the number of total cells, neutrophils and macrophages in the BALF were decreased significantly. Furthermore, RA may enhance oxidase dimutase (SOD) activity during the inflammatory response to LPS-induced ALI. And we further demonstrated that RA exerts anti-inflammation effect in vivo models of ALI through suppresses ERK/MAPK signaling in a dose dependent manner. These studies have important implications for RA administration as a potential treatment for ALI.     

乙醛酸和草酸的毛细管区带电泳分析

建立了同时测定乙醛酸和草酸的毛细管区带电泳法。考察了缓冲溶液的种类、浓度和pH以及分离电压等因素对分离结果的影响。在缓冲溶液为20 mmol/L硼砂-5.5 mmol/L邻苯二甲酸氢钾(pH 9.0)、分离电压20 kV、检测波长212 nm的优化条件下,11 min内即可实现对目标物的分离。乙醛酸和草酸分别在0.8～20 g/L和1.2～20 g/L范围内线性关系良好,相关系数分别为0.9993和0.9975;方法的检出限分别为0.2和0.4 g/L(信噪比为3);样品的加标回收率为98.3%～102.5%,相对标准偏差为0.35%～0.61%。该方法操作简便、快速、成本低廉,已应用于实际样品的分析,并获得了令人满意的结果。