Preliminary evaluation of interactions between selected alcoholamines and model skin sebum components

The aim was to evaluate the interaction between selected alcoholamines and components of artificial skin sebum. The rate and depth of penetration into the lipophilic bead imitating pilosebaceous unit lumen was applied for alcoholamine penetration activity assay. The activity differentiation of 0.5% aqueous alcoholamine solutions with a potential cleansing effect on the pilosebaceous unit was performed. The depth of aminomethylpropanol penetration increased from 0.080 mm after 15 min to 3.049 mm after 72 h. The depth of aminomethylpropendiol penetration increased with time from 0.148 to 4.064, respectively, of diisopropanolamine from 0.481 to 4.626, triethanolamine from 0.236 to 4.342, triisopropanolamine from 0.275 to 2.392 and trometamol from 0.338 to 4.580. The products of alcoholamines reaction with the model skin sebum are easily dispersed in water. The rate of alcoholamines reaction with the model skin sebum depends on the alcoholamine, being the highest in the case of diisopropanolamine, decreasing to minimum for triisopropanolamine. Selected alcoholamines would be applied in ex vivo and in vivo research.     

A kinetic study of the chlorination of tertiary alcoholamines in alkaline media

The kinetics of the chlorination of various tertiary alcoholamines by hypochlorite have been studied in alkaline media. A reaction mechanism consistent with the experimental results is put forward, and a relationship is established between the rate constants and the polar parameter (Σσ*) of the substituents.     

Assessment of dispersion‐improved exchange‐correlation functionals for the simulation of CO2 binding by alcoholamines

In this study, 12 bound complexes were selected to construct a database for testing 15 dispersion‐improved exchange‐correlation (XC) functionals, including hybrid generalized gradient approximation (GGA), modified using the Grimme's pairwise strategy, and double hybrid XC functionals, for specifically characterizing the CO₂ binding by alcoholamines. Bound complexes were selected based on the characteristics of their hydrogen bonds, dispersion, and electrostatic (particularly between the positive charge of CO₂ and the lone pair of N of alcoholamines) interactions. The extrapolated binding energy from the aug‐cc‐pVTZ (ATZ) to aug‐cc‐pVQZ (AQZ) basis set at the CCSD(T)/CBS(MP2+DZ) level was used as the reference for the XC functional comparison. M06‐2X produced the optimal agreement if the optimized geometries at MP2/ATZ level were chosen for all the test bound complexes. However, M06‐L, ωB97X, and ωB97, and were preferred if the corresponding density functional theory (DFT) optimized geometries were adapted for the benchmark. Simple bimolecular reaction between CO₂ and monoethanolamine simulated using polarizable continuum solvation model confirmed that ωB97, ωB97X, and ωB97XD qualitatively reproduced the energetics of MP2 level. The inconsistent performance of the tested XC functionals, observed when using MP2 or DFT optimized geometries, raised concerns regarding using the single‐point ab initio correction combined with DFT optimized geometry, particularly for determining the nucleophilic attack by alcoholamines to CO₂. © 2014 Wiley Periodicals, Inc.     

Synthese makrocyclischer Arsenigsäureester

Synthesis of Macrocyclic Arsinous Acid Esters The reactions of alcoholamines and thioglykol, respectively, with aminoarsines lead to the formation of 8- and 10-membered, cyclic arsinous acid esters. The reaction of different acid NH, OH and SH groups with aminoarsines are examined. I.r. and ¹H n.m.r. data are presented and discussed.     

Crystalline alcoholamine borates and the triborate monoanion

The triborate and pentaborate compounds 3-hydroxy-2,2-dimethylpropylammonium triborate(1+), [HOCH2C(CH3)2NH3][B3O3(OH)4] (1), and 2-hydroxyethylammonium pentaborate(1-), [HOCH2CH2NH3][B5O6(OH)4].H2O (2), were prepared by crystallization from concentrated aqueous boric acid solutions containing the respective alcoholamines at a boric acid-alcoholamine mole ratio of 3.33:1.00. Compound 1 crystallized in the triclinic space group P1 with a = 5.9595(9) A, b = 6.3024(9) A, c = 15.594(2) A, alpha = 91.218(2) degrees , beta = 91.138(2) degrees , gamma = 118.034(2) degrees , V = 516.56(13) A (3), and Z = 2; 2 crystallized in the monoclinic space group P2 1/ n with a = 11.2469(8) A, b = 9.5091(6) A, c = 11.5422(8) A, beta = 90.175(1) degrees , V = 1234.41(15) A (3), and Z = 4. Compound 1 contains a rare example of a structurally characterized hydroxyl-hydrated triborate monoanion. Comparisons are made with other known examples of this anion.     

Addition of N-carbobenzyloxy-L-tryptophan as a co-template molecule to molecularly imprinted polymer monoliths for (+)-nilvadipine

Molecularly imprinted polymer (MIP) monoliths for (+)-nilvadipine have been prepared using 4-vinylpyridine as a functional monomer and toluene/1-dodecanol as a porogen without or with addition of N-carbobenzyloxy-L-tryptophan (Cbz-L-Trp) as a co-template molecule. The MIP monoliths prepared with (+)-nilvadipine as a sole template molecule had no macro through-pores, while those could be formed by addition of Cbz-L-Trp as the co-template molecule. Furthermore, on the former nilvadipine enantiomers could not be separated, but on the latter they could. The presence of Cbz-L-Trp affected the polymerization process and resulted in forming macro through-pores of the MIP monoliths for (+)-nilvadipine and attaining separation of nilvadipine enantiomers. These results suggest that co-addition of Cbz-L-Trp could be effective for preparing MIP monoliths for (+)-nilvadipine, whose preparation is difficult.     

Novel CuS nanofibers using organogel as a template: controlled by binding sites

A new cholesterol organogelator 1 was synthesized, which was confirmed as an effective gelator for various organic solvents and could self-assemble into network fibers in some organic solvents. Moreover, gelator 1 could act as templates for the synthesis of various CuS nanofibers with different helical pitches. For example, when H(2)S was used as the sulfur source, straight and bending helical CuS nanofibers with a pitch of 100-200 nm could be fabricated in butyl acetate and benzene-butanol gel systems, respectively, while bending CuS nanofibers with a similar helical pitch (ca. 50 nm) could be obtained when thioacetamide was used as the sulfur source in both gel systems. It was first found that the morphologies of inorganic nanofibers could be controlled by the binding sites between the inorganic precursor and the organogel.     

Carbon nanotube-enhanced separation of DNA fragments by a portable capillary electrophoresis system with contactless conductivity detection

It was demonstrated that separation of DNA fragments by a CE-contactless conductivity detection system (CE-CCD) could be enhanced with multiple-wall carbon nanotubes (MWCNs) as buffer additive. For HaeIII digest of PhiX174 DNA, optimized MWCN concentration was obtained when the MWCN was above its threshold concentration, at which MWCN could form a network in the buffer as pseudostationary phase to provide additional interaction sites. In the case of larger DNA, MWCN near or below its threshold concentration was enough to provide great improvement of the resolution, which was shown by the separation of the 2-Log DNA ladder. Furthermore, the buffer containing MWCN could provide a more stable baseline in the CE-CCD system, owing to less fluctuation of its conductivity. Compared with CE-UV, CE-CCD with MWCN could provide lower LODs as well as better resolution.     

Sulfonated graphene oxide: the new and effective material for synthesis of polystyrene-based nanocomposites

The new sulfonated graphene oxide (S-GO) was prepared and firstly used as effective materials for the synthesis of polystyrene/graphene nanocomposites via Pickering emulsion polymerization. The functionalized, chemically modified GO nanosheets were obtained via facile covalent functionalization with a reactive surfactant, sulfanilic acid. It was found that Pickering emulsion could be formed by simple self-assembly method using the S-GO as a stabilizer (just need 1 wt% relative to the oil phase), which could be adsorbed at the oil–water interface to stabilize the emulsion effectively. After the Pickering emulsion polymerization of styrene, the polystyrene/S-GO nanocomposites were prepared successfully. It is noteworthy that the S-GO not only could be used as a highly effective surfactant for styrene monomers but also could be homogeneously dispersed and incorporated into the polymeric matrix.     

High-speed chiral separations on a microchip with UV detection

Fast chiral separations of a variety of basic and acidic compounds could be realized on microfluidic quartz chips. A microchip electrophoresis instrument equipped with a linear imaging UV-detector was used. The usually applied but troublesome fluorescence tagging in order to enable fluorescence detection could be omitted. Using sulfated cyclodextrins as chiral selectors baseline separation of 19 compounds could be achieved in less than 1 min with high reproducibility. The relative standard deviation of migration time was below 7%. The fastest separation could be performed in 2.5 s which is to date the fastest separation of enantiomers reported. It was possible to apply microchip electrophoresis (MCE) for the determination of high enantiomeric excess (ee) values, as exemplarily shown for pseudoephedrin where 2% of the minor enantiomer could reliably be determined beside high amount of the other isomer. Successful separation of a mixture of 3 chiral drugs could be performed in a single run in less than 11 s utilizing a separation length of only 12 mm. These results show that MCE has great potential for fast chiral analysis and high-throughput screening.     

Kinetics of Cu2+ Reduction and Nanoparticle Nucleation at Micro-scale 1,2-Dichlorobenzene-water Interface Studied by Cyclic Voltammetry and Square-wave Voltammetry

Reduction and nanoparticle nucleation of Cu²⁺ by decamethylferrocene was studied with cyclic and square-wave voltammetry at a microscale liquid–liquid interface established at the tip of a micropipette. With square-wave voltammetry, two reduction steps could be distinguished as two separate current waves. Comparing the experimental results of cyclic voltammetry with finite element method simulations, particle growth could be observed as an increasing limiting current. Furthermore, kinetic parameters could be estimated with square-wave voltammetry simulations following Butler-Volmer kinetics.     

Transformations of chromanol and tocopherol and synthesis of ascorbate conjugates

α-Tocopherol and as a model compound pentamethylchromanol could be transferred into simple and more complex 5a-ether derivatives including galactopyranose as well as ascorbic acid conjugates. Following elaboration of a glucopyranoside spacer element this could be used for tethering the vitamin E and the vitamin C components to give novel conjugates for subsequent biostudies concerning their proposed synergism of antioxidant properties in tissues.     

两种不同Pb源对PbSe纳米晶生长的影响

采用有机相合成法, 分别以PbO和醋酸铅[Pb(Ac)₂]作为铅源, 研究了在不同反应温度和反应时间下, 不同铅源对PbSe纳米晶生长的影响. 实验结果表明, 以PbO作为铅源, 油酸(OA)作为配体时, 在不同的反应温度下得到了球形PbSe纳米晶和截角八面体PbSe纳米晶; 选择Pb(Ac)₂作为铅源时, 在不同的温度下得到了PbSe纳米花和PbSe纳米星. 选择不同铅源得到的PbSe纳米晶形貌完全不同, 这主要是由于醋酸根的引入产生了不同的空间位阻, 引起纳米晶导向吸附并形成纳米花. 而随着反应温度的升高和反应时间的延长, 这些不同形貌的PbSe纳米晶最终会演变成纳米立方块, 这主要是由PbSe的晶体特性决定的.     

A comparative study of assembly and disassembly process of dimeric and monomeric cyanine dyes with DNA templates

H-aggregates of dimeric cyanine dyes (TC-P4) formed in PBS could be disassembled by G-quadruplex into dimer and/or monomer, resulting in higher fluorescent selectivity than its corresponding monomer (TC).     

Using a deoxyribozyme ligase and rolling circle amplification to detect a non-nucleic acid analyte, ATP

An allosteric ribozyme (aptazyme) has been used to transduce the binding of a small organic analyte (ATP) into the ligation of a circular template for rolling circle amplification (RCA). An ATP-activated deoxyribozyme ligase was immobilized on a glass slide and, upon addition of ATP, catalyzed the ligation of a circular padlock probe. The ligated products could be directly amplified and visualized via RCA. The coupled reaction exhibited could detect as little as 1 muM of ATP and could discriminate against structurally similar nucleotides such as GTP, CTP, and UTP. Cooperative ATP activation of the deoxyribozyme was faithfully mimicked by RCA, yielding an amplified "switch" that was responsive to ATP concentration.     

β-Cyclodextrin polymer based fluorescence enhancement method for sensitive adenosine triphosphate detection

A sensitive and facile method for adenosine triphosphate detection has been developed that based on the prominent fluorescence enhancement capability of β-cyclodextrin polymer to pyrene through host-gest interaction.     

Determination of the solubility of vinyl stearate in water by a monolayer technique

Summary The surface activity of vinyl stearate has provided a method for determining its solubility in water to be 0,7±0,2×10^–6 mole/litre. The methods described above could be used to determine the solubility in water of any sparingly soluble surface active compound, such as stearic acid or cetyl alcohol, which formed a stable monolayer at theA/W interface. Method A could be used for compounds with a solubility as low as 10^–5 mole/litre where as for Method B solubilities as low as 10^–7 mole/litre could be measured.     

Behavior of basic compounds in ion-exchange capillary electrochromatography with low-pH carrier electrolytes

This work describes the separation of basic aromatic compounds by capillary electrochromatography employing acidic carrier electrolytes and bare silica as well as strong cation-exchange stationary phases. A mixed-mode separation mechanism was involved, comprising chromatographic interactions (adsorption, ion-exchange) as well as electrophoretic migration. The influence of ion-exchange on the retention/migration of the solutes could be manipulated according to procedures commonly employed in ion chromatography. These include variations of the eluting strength and/or the concentration of the competing ion present in the background electrolyte. Using this approach, separation times could be shortened and changes in selectivity could be achieved for a number of analytes.     

High efficient delivery of siRNA into tumor cells by positively charged carbon dots

Abstract

Nowadays development of safe and simple siRNA delivery system is still a great challenge. Carbon dots have attracted considerable attention in bioimaging, drug delivery, nanosensors, and other fields during the past few years. In this study, we successfully developed carbon dots (TEPA-CDs) as siRNA nanocarriers based on glucose and tetraethylene pentamine. TEPA-CDs have a mean diameter of less than 10?nm and positive charged decoration. TEPA-CDs could condense siRNA into stable complexes without no obvious premature release. Cellular uptake analysis clearly showed that Cy3-labeled siRNA could be uptake by HeLa cells. GFP expression in HeLa-EGFP cells could be significantly inhibited by TEPA-CDs/siRNA complexes. Our study indicated that TEPA-CDs could be used as a siRNA nanocarrier to tumor cells.     

聚合物与纳米晶的杂化及性能优化

聚合物-纳米晶杂化材料因结合了有机和无机材料的优点而逐渐地受到了人们普遍的关注,聚合物为纳米晶的形成与生长提供了优良的环境,纳米晶的引入同样也增加和强化了聚合物的功能特性.如聚硫代氨基甲酸酯与TiO2杂化的高折射率薄膜,该薄膜不仅保持了原有的性能,而且有较高的折射率.此外,还有许多不同纳米粒子与不同聚合物的杂化体系.如...