Improved thromboresistance and analytical performance of intravascular amperometric glucose sensors using optimized nitric oxide release coatings

In this work, nitric oxide (NO) release coatings designed for intravenous amperometric glucose sensors are optimized through the use of a polylactic acid (PLA) layer doped with a lipophilic diazeniumdiolated species that releases NO through a proton-driven mechanism. An Elast-Eon E2As polyurethane coating is used to both moderate NO release from the sensor surface and increase the sensor''s linear detection range toward glucose. These sensors were evaluated for thromboresistance and in vivo glucose performance through implantation in rabbit veins. By maintaining NO flux on a similar scale to endogenous endothelial cells, implanted glucose sensors exhibited reduced surface clot formation which enables more accurate quantitative glucose measurements continuously. An in vivo time trace of implanted venous sensors demonstrated glucose values that correlated well with the discrete measurements of blood samples on a benchtop point-of-care sensor-based instrument. The raw measured currents from the implanted glucose sensors over 7 h time periods were converted to glucose concentration through use of both a one-point in vivo calibration and a calibration curve obtained in vitro within a bovine serum solution. Control sensors, assembled without NO release functionality, exhibit distinctive surface clotting over the 7 h in vivo implantation period.     

PW11Cu/TiO2膜光催化剂的制备及可见光催化性能

以PW₁₁Cu为可见光活性组分,TiO₂为载体结构组分,采用溶胶-凝胶法制备了PW₁₁Cu/TiO₂复合膜可见光催化剂,并用UV-Vis DRS、IR、Raman、XRD、SEM、TEM等手段对催化剂的光吸收性质、化学组成、晶相、表面结构和形貌进行了表征,同时,以模型污染物RhB的可见光降解为探针评估了它的光催化活性,考察了膜处理温度、PW₁₁Cu含量和溶液酸性对催化活性的影响,最后,通过催化剂循环降解RhB试验评估了PW₁₁Cu/TiO₂膜的稳定性。实验结果表明,PW₁₁Cu/TiO₂膜对可见光有明显吸收,低温(100℃)处理的膜为无定形态,高温(500℃)处理的膜为多晶态;低温处理的膜具有较高的可见光催化活性,用于RhB的可见光催化降解,在中性条件下反应80 min,RhB的降解率为100%,TOC去除达32%(4 h);提高溶液酸性有利于催化剂活性的提高,在pH=2.5的条件下,达到100%的RhB降解仅需30 min。在本实验条件下,PW₁₁Cu的最佳剂量是3.0 g。经过10次循环降解RhB,催化剂的光催化活性仍保留约90%。     

Development and validation of polymerized high internal phase emulsion monoliths coupled with HPLC and fluorescence detection for the determination of trace tetracycline antibiotics in environmental water samples

A polymerized high internal phase emulsion monolith was used as a novel sorbent for solid‐phase extraction coupled with high‐performance liquid chromatography and fluorescence detection for the determination of oxytetracycline, tetracycline, doxycycline, and chlorotetracycline in environmental water samples. The polymerized high internal phase emulsion monolithic column was prepared by the in situ polymerization of the continuous phase of a high internal phase emulsion containing glycidyl methacrylate, styrene, and divinylbenzene in pipette tips, and then functionalized with iminodiacetic acid. The resulting monolith exhibited highly interconnected porosity and large surface areas, making it an excellent candidate as an solid‐phase extraction sorbent for the enrichment of trace tetracycline antibiotics. Several factors affecting the extraction performance of polymerized high internal phase emulsion monoliths, including the pH of sample solution, the eluting solvents, the sample loading flow rate and volume, were investigated, respectively. Under the optimized conditions, the mean recoveries of oxytetracycline, tetracycline, doxycycline, and chlorotetracycline spiked in pond and farm wastewater samples ranged from 78.1 to 119.3% with relative standard deviation less than 15%. The detection limits (S/N = 3) of the proposed method were in the range of 51–137 pg/mL. This study demonstrated that the monolithic polymerized high internal phase emulsion would be promising solid‐phase extraction sorbents in the extraction and proconcentration of trace analytes from complex samples.     

Six-step synthesis of Leonurine and toxicity study on zebrafish

Leonurine (1), an important ingredient in leonurus sibiricus L., can be used for some gynecological disease. We have developed a concise and efficient synthetic route of Leonurine, which can be optimized for mass production. Commercially available compound 6 and 2,3-dihydrofuran (7) were used as starting materials. And the toxicity study on zebrafish shows that Leonurine would promote the hatching of zebrafish embryos at low concentration and result in acute death or chronic lethal toxicity at high concentration.     

Four Mixed 3d-4f 12-Metallacrown-4 Complexes: Syntheses,Structures and Magnetic Properties

The incorporation of Ln^III ions into the 12-metallacrown-4 topology affords the formation of four mixed 3d-4f pentanuclear complexes of compositions [NH(C₂H₅)₃]{[Ln(OAc)₄] [12-MC _Mn ^III _(N)shi-4]}·xH₂O (Ln = Sm (1), Gd (2), Tb (3), Dy (4); x = 0.5 for 1 and 3, x = 0.25 for 2, x = 0 for 4; H₃shi = salicylhydroxamic acid). Compounds 1–4 were obtained from the reactions of H₃shi with Mn(CH₃COO)₂·4H₂O and Ln(NO₃)₃·6H₂O, in the presence of N(C₂H₅)₃. They all contain a crown-like [Mn₄Ln(μ-NO)₄]¹¹⁺ core with four Mn^III atoms being at the rim of the crown and an Ln^III ion occupying the dome of the crown. The peripheral ligation about the core is provided by four η¹:η¹:µ acetate groups. The identity of the Ln^III ions slightly affects the 12-metallacrown-4 frameworks, as demonstrated by the gradual decrease of the distances between the Ln^III ions and the centres of the Mn₄ planes (1.85 Å for 1, 1.81 Å for 2, 1.80 Å for 3, and 1.77 Å for 4). Variable-temperature dc magnetic susceptibility studies were carried out on polycrystalline samples of 1–4. Antiferromagnetic interactions are determined for complexes 1–4.     

Facile one-step extraction and oxidative carboxylation of cellulose nanocrystals through hydrothermal reaction by using mixed inorganic acids

A facile and efficient approach to prepare carboxylated cellulose nanocrystals (CCNCs) is presented through a novel one-step hydrothermal procedure by using a mixed acid system of hydrochloric acid and nitric acid (HCl/HNO₃). The as-prepared cellulose nanoparticles were characterized by scanning electron microscopy, wide angle X-ray diffraction, conductometric titrations, Fourier transform infrared spectrometry and thermal gravimetric analysis. The results showed that the combination of the mixed acid and hydrothermal reaction can speed up the process of CCNC preparation, and then high quality of the product could be obtained at relatively low acid concentration. It is found that the addition of nitric acid could not only promote the conversion of surface groups on the cellulose nanocrystals (CNCs), but also have significant influences on the yield, particle size and microstructure of CNCs. For the volume ratio of HCl/HNO₃ of 7:3, the as-prepared CCNCs exhibited the largest length to diameter ratio and narrowest dimension distributions as well as maximum degree of oxidation of 0.12. In addition, high dispersion stability for the CCNCs could be observed due to the existence of negative carboxyl groups. This approach based on one-step oxidative carboxylation greatly simplified the preparation of CCNCs with high yield and high crystallinity under mild hydrothermal condition.     

Separation of Ni<Superscript>2+</Superscript> from ammonia solution through a supported liquid membrane impregnated with Acorga M5640

Separation of Ni²⁺ from ammonia/ammonium chloride solution using a flat-sheet supported liquid membrane (SLM) impregnated with Acorga M5640 in kerosene was investigated. The fundamental experimental variables influencing Ni²⁺ transport, such as ammonia concentration, carrier concentration, H₂SO₄ concentration in the stripping solution, stirring speed, and initial Ni²⁺ concentration were studied. Almost all of Ni²⁺ was transported from the feed to the stripping phase after 18 h of operation with a permeability coefficient of 9.28 × 10^?6 m s^?1 under optimum conditions: stirring speed of 1000 rpm in both phases, 20 vol.% Acorga M5640 as the carrier, 1.70 mmol L^?1 Ni²⁺ in the feed phase and 0.10 mol L^?1 H₂SO₄ in the stripping phase. The flux value of Ni²⁺ was 15.82 × 10^?6 mol m^?2 s^?1. Additionally, the influences of temperature and ultrasound on flux were examined, and results indicated that higher temperature and ultrasonic assistance improved transport of Ni²⁺ through the SLM. Selective separation of nickel from cobalt in an ammonia/ammonium chloride solution was also achieved through SLM. The stability of the SLM was examined on a continuous run mode and satisfactory stability of the nickel permeation was observed for 84 h (7 runs).     

基于新型螺氧杂蒽主体的高效蓝色磷光有机发光二极管

We synthesized a series of novel spiro[fluorene-9, 9'-xanthene] (SFX)-based host materials via a one-step palladium-catalyzed cross-coupling reaction. These materials have high triple energy levels and high yield, and thus can be used as hosts for blue phosphors. Blue phosphorescent organic light-emitting devices (PHOLEDs) with a bis (3, 5-difluoro-2-(2-pyridyl) phenyl-(2-carboxypyri-dyl) iridium (Ⅲ) (FIrpic) emission were fabricated. Furthermore, we applied cohosts composed of one of the new synthesized materials and the hole transport material di-[4-(N, N-ditolyl-amino)-phenyl]cyclohexane (TAPC) to the blue PHOLEDs to successfully acquire efficient blue emissions. The SFX-based material provided efficient energy transfer while TAPC improved the mobility of the cohost as well as reduced the working voltage. Maximum current efficiencies of 22.56 and 25.93 cd·A^-1 and the maximum brightnesses of 6421 and 6196 cd·m^-2 were obtained for the PHOLEDs with TAPC: 2-(9-phenyl-fluoren-9-yl) spiro[fluorene-9, 9'-xanthene] (PF-SFX) and TAPC: 2-(9-(4-(octyloxy)-phenyl)-9H-fluoren-9-yl) spiro[fluorene-9, 9'-xanthene] (C8OPF-SFX) cohosts, respectively. The experimental results obtained for the four SFX-based host materials were enough to declare that SFX is an effective main unit that can be used to build efficient host materials for blue phosphors containing only C, H, and O basic elements.     

Cu2O/g-C3N4催化合成吲哚-2-羧酸酯

我们通过原位还原的方法将吸附在g-C3N4表面上Cu2+还原,制备出Cu2O/g-C3N4复合材料,并利用XRD、SEM、FT-IR、XPS等分析手段表征Cu2O/g-C3N4.表征结果显示:Cu元素主要以Cu2O的形式吸附在g-C3N4载体上.另外,还考察了Cu2O/g-C3 N4在“一锅法”合成吲哚-2-甲酸乙酯的反应中的催化性能.结果表明:即使在较低的催化担载量和温和的反应条件下,Cu2O/g-C3 N4仍能表现出良好的催化性能并获得44.1％的收率.     

超高效液相色谱-四极杆/静电场轨道阱高分辨质谱检测食品中的牛奶过敏原酪蛋白

基于超高效液相色谱-四极杆/静电场轨道阱高分辨质谱系统,建立了食品中牛奶过敏原酪蛋白的快速筛查和定量检测方法。样品经缓冲液提取后,采用5 kD超滤膜去除小分子杂质,得到蛋白质提取液。以数据依赖采集(data-dependent acquisition,DDA)方式获得全扫描质谱图,进行蛋白质定性确证,以平行反应监测(parallel reaction monitoring,PRM)技术对目标特征肽段进行定量分析。针对特征肽段,设计并合成了内标肽和内标物质,以降低基质效应和抵消处理过程中的损失。该方法应用于食品中的α-酪蛋白、β-酪蛋白和κ-酪蛋白的快速筛查和定量检测。结果表明,该方法在5~250μg/L范围内线性关系良好,定量限为0.2~5.5μg/kg,平均回收率在68.8%~104.4%之间,RSD6%。该方法可用于果汁饮料、果酱、面包、早餐谷物中牛奶过敏原酪蛋白的快速筛查和定量分析。