Simultaneous determination of 5-hydroxytryptamine and dopamine using ionic liquid functionalized graphene

Ionics - An electrochemical sensor for simultaneous determination of 5-hydroxytryptamine (5-HT) and dopamine (DA) was developed in this paper based on an ionic liquid functionalized-graphene...     

Modeling and prediction of transmission laser bonding process between titanium coated glass and PET based on response surface methodology

Laser bonding parameters play a very significant role in determining the quality of laser transmission bonding between PET films and titanium films coated glass sheets. In order to achieve good bond strength and minimal bond width, three key process parameters affecting the bond quality of transmission laser bonding, namely, laser power, bond speed and film thickness were optimized by response surface methodology in this paper. Response surface methodology (RSM) was used to develop mathematical models between the key process parameters and the desired responses and the central composite design (CCD) was utilized to conduct experimental planning. The samples were tested using an electromechanical universal micro-tester in order to determine bond strength. The morphology of the bonded area was observed with an optical microscope. The interaction effect of main process parameters on bond quality was researched. Design Expert analysis indicated that the best laser power, bond speed and film thickness on bond quality were 11.2 W, 4 mm/s and 163 nm, respectively. Finally, the experimental results are consistent with the predicted, which illustrates that the developed mathematical models can predict the responses adequately.     

A pH-Sensitive Biopolymer-Based Superabsorbent Nanocomposite from Sodium Alginate and Attapulgite: Synthesis,Characterization, and Swelling Behaviors

Graft copolymerization reaction among sodium alginate (NaAlg), sodium acrylate (NaA), and nanoscale attapulgite (APT) was performed to fabricate a novel pH-sensitive NaAlg-g-PNaA/APT superabsorbent nanocomposite. FTIR spectra proved NaA monomers were grafted onto NaAlg backbone and APT participated in polymerization. FESEM, TEM, and TGA analyses revealed the better dispersion of APT fibrils in the matrix and the improved thermal stability. The swelling capacity and rate of the superabsorbent was clearly enhanced after introducing APT. The external salts and surfactants showed greater influence on the swelling behaviors. The nanocomposite exhibited reversible On-Off pH-sensitivity between pHs 2.0 and 7.4, and the intriguing pH-triggered deswelling behavior in various polyvinylperrodone (PVP) solutions was observed.     

一种新型铕配合物的合成和发光性能

合成了一种新的β-二酮,1,5-二苯乙烯基乙酰丙酮（dsacac）并将其作为第一配体,1,10-邻菲罗啉（Phen）作为第二配体合成了一种新型的铕三元配合物Eu（dsacac）3phen。对配合物进行了元素分析、核磁共振、红外光谱、紫外吸收光谱、光致发光光谱以及热重分析。结果表明：配合物具有较好的热稳定性,起始分解温度为303℃。配合物中的有机配体dsacac和phen能够有效地的把吸收的能量传递给中心Eu^3＋离子,强烈敏化Eu^3＋发光,Eu^3＋发光的最强发射波长为615nm,半峰宽为9．6nm。材料的色纯度为0．9866,是一种高效的红色发光材料。     

Metabolomics method based on ultra high performance liquid chromatography with time‐of‐flight mass spectrometry to analyze toxins in fresh and dried toad venom

Drying is a critical step to prolong the storage time in natural medicine processing but it changes the chemical characteristics of the product. In this study, research was performed to characterize the metabolomic changes in toad venom induced by vacuum‐drying at 60°C and air‐drying at room temperature by ultra high performance liquid chromatography coupled with pattern recognition approaches. In total 52 metabolites, down‐regulated or up‐regulated, were identified as potential chemical markers. Compared with fresh toad venom, vacuum‐drying at 60°C succeeded in raising the conjugated‐type bufadienolide content significantly, while the content of free‐type bufadienolides were slightly reduced. On the other hand, toad venom air‐dried at room temperature presented a relatively low amount of bufadienolides compared with fresh venom. For example, the content of several known anti‐tumor components (gamabufotalin, bufotalin, cinobufagin, etc.) were significantly reduced. The 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide bioassay further showed that venom air‐dried at room temperature had weaker anti‐tumor activity on human hepatocellular carcinoma SMMC‐7721 proliferation in vitro than samples vacuum‐dried at 60°C. These results showed that the great metabolomic changes of toad venom occurred during the drying process, suggesting that a proper drying procedure is important for sustaining the chemical quality of natural medicines.     

Facile synthesis of amino-functionalized hollow silica microspheres and their potential application for ultrasound imaging

By using the positive charged polystyrene (PS) microsphere as template, mono-disperse amino-(-NH(2)) functionalized hollow silica microspheres (HSMS-NH(2)) with ~1310 nm in diameter and uniform shells were successfully prepared with a modified sol-gel process. The amino functionalized silica were coated on the PS microspheres via ammonia catalysis, co-hydrolysis and condensation of TEOS and APTES, and then the PS templates were selectively dissolved in THF solution to form the functional hollow microspheres. The controllable thickness (35-85 nm) and amino density (2.46×10(-5)-6.18×10(-5) mol/g) of the shells could be facilely tuned by changing the amount of TEOS and APTES. In vitro ultrasound images of as-prepared HSMS-NH(2) with different concentrations in the physiological saline solution were further investigated. The obvious signal enhancement indicates that as-prepared HSMS-NH(2) has a great potential application for ultrasound imaging.     

Water-soluble magnetic CoO nanocrystals functionalized with surfactants as T2-weighed MRI contrast agents in vitro

CoO nanocrystals (CoO NCs) were synthesized by thermal decomposition of the cobalt-oleate complex. For biological applications, water-soluble CoO NCs were obtained via a facile phase-transfer method by employing amphiphilic surfactants, such as anionic (sodium dodecyl sulfate, SDS), neutral (Pluronic F127, PF127) and cationic (cetyltrimethyl ammonium bromide, CTAB). Field-dependent magnetization measurements indicated that the type of surfactants around the CoO NCs plays a crucial role in their magnetic properties. Among them, CoO NCs functionalized with PF127 have the largest saturated magnetization (M(s)) of 10.9 emu g(-1). To clarify the potential application in magnetic resonance imaging (MRI), longitudinal relaxivities (r(1)) and transverse relaxivities (r(2)) of the functionalized CoO NCs were investigated in detail. The r(2)/r(1) of CoO NCs functionalized with PF127 is about 26. Therefore, they should be novel excellent potential T(2) contrast agents. Furthermore, methyl thiazolyl tetrazolium (MTT) assays show that they have low cytotoxicity in living cells. In vitro experiment results indicated that they can be taken up by living cells effectively, showing the obvious decrease of the transverse relaxation time T(2) after internalization.     

Synthesis of oxygen-deficient luminescent mesoporous silica nanoparticles for synchronous drug delivery and imaging

Oxygen-deficient luminescent mesoporous silica nanoparticles with uniform morphology/size and integrated mesoporosity-luminescent property in a single nanoparticle are successfully synthesized by a bottom-up self-assembly route followed by a post-calcination process, and can be used to facilely load/deliver drugs into cells and luminescently image cells.     

纳米Eu2O3/硫酸酯化壳聚糖杂化材料的制备及其抗凝血性能研究

利用表面接枝的方法制备了纳米Eu2 O3/硫酸酯化壳聚糖杂化材料,并用IR,TG和SEM等方法对产物进行了表征,结果表明硫酸酯化壳聚糖接枝在了经过活化后的纳米氧化物表面,细胞毒性实验证明材料具有较低的细胞毒性和较好的细胞相容性.抗凝血实验说明材料具有良好的抗凝血性能.表面接枝方法提高了壳聚糖类化合物的抗凝作用,弥补了比...     

Stokes问题的各向异性平行四边形有限元逼近

1 引言 Stokes问题是标准的混合问题,速度与压力同时计算,关于该问题有限元求解的文章很多(见文献[1-5])但大多都是基于对区域的正则剖分或拟一致剖分,即要求网格剖分满足hk/pK≤C,(A)K∈Jh,其中C>0为一常数,hk,pK分别为单元K的直径及内切园直径,在实际应用问题中,由于边界层或区域的拐角处需考虑物质的各向异性特征,此时对空间区域Q的剖分不再满足正则性或拟一致条件,而需要用各向异性网格剖分,才能更贴切地描述其真实情形.