Rapid purification and scale-up of honokiol and magnolol using high-capacity high-speed counter-current chromatography

In this paper, a rapid separation approach has been developed using high-capacity high-speed counter-current chromatography (high-capacity HSCCC) to isolate and purify honokiol and magnolol, which are the main bioactive constituents from Houpu. The optimization of the solvent selection process, sample loading volume and flow rate is systematically studied using analytical high-capacity HSCCC. The optimized parameters obtained rapidly at analytical scale were used for a 1000 x scale-up preparative run using pilot scale high-capacity HSCCC in a MAXI-DE centrifuge. A crude sample of 43 g was successfully separated and the fractions were analysed by high-performance liquid chromatography (HPLC). This large scale preparative single step run yielded 16.9 and 19.4 g of honokiol and magnolol with purities of 98.6 and 99.9%, in only 20 min. This is the first time that high-performance counter-current chromatography has been used to purify multiple gram grade bioactive compounds in less than 1h and at such high concentrations of final products (10.8 g/l for magnolol and 7.0 g/l for honokiol).     

Charge transfer complexes of electron-rich naphthalene peri-dichalcogenides with TCNQ

The electronic structures of several highly electron-rich 2,7-dimethoxynaphthalene peri-dichalcogenides were evaluated using optical and electrochemical methods, as well as by DFT calculations. Charge transfer complexes were formed with tetracyanoquinodimethane and resulted in absorption features that span from 300 nm to 1600 nm and HOMO–LUMO energy gaps as low as 0.8 eV.     

Defining and using microbial spectral databases

This work shows how fingerprints of mass spectral patterns from microbial isolates are affected by variations in instrumental condition, by sample environment, and by sample handling factors. It describes a novel method by which pattern distortions can be mathematically corrected for variations in factors not amenable to experimental control. One uncontrollable variable is "between-batch" differences in culture media. Another, relevant for determination of noncultured extracts, is differences between the cells' environmental experience (e.g., starved environmental extracts versus cultured standards). The method suggests that, after a single growth cycle on a solid medium (perhaps, a selective one), pyrolysis MS spectra of microbial isolates can be algorithmically compensated and an unknown isolate identified using a spectral database defined by culture on a different (perhaps, nonselective) medium. This reduces identification time to as few as 24 h from sample collection. The concept also proposes a possible way to compensate certain noncultured, nonisolated samples (e.g., cells concentrated from urine or impacted from aerosol or semi-selectively extracted by immunoaffinity methods from heavily contaminated matrices) for identification within half an hour. Using the method, microbial mass spectra from different labs can be assembled into coherent databases similar to those routinely used to identify pure compounds. This type of data treatment is applicable for rapid detection in biowarfare and bioterror events as well as in forensic, research, and clinical laboratory contexts.     

Patterning and modification of PDMS surface through laser micromachining of silicon masters and molding

We describe preparation of micro patterned PDMS sample surfaces and their chemical modification for the purposes of increased hydrophobicity. The process includes ablation of micrometer sized patterns on a silicon master by pulsed radiation from a Nd:YAG laser, transfer of the patterns to PDMS through molding, and chemical modification of the topmost surface layers of the polymer sample by further laser irradiation and UV/ozone treatment. The samples were characterized by XPS, FTIR, contact angle measurements, optical microscopy and SEM. The study shows the feasibility of the method to manufacture regular patterns with micron-sized cylindrical pillars and to control surface composition. In the absence of chemical modification of the surfaces due to preparation, we compare the effect of increased roughness on the contact angle with theoretically predicted values. Samples with patterned and chemically modified surfaces due to UV/ozone treatment show reduced hydrophobicity. PACS 52.38.Mf; 81.65.Cf; 81.05.Lg     

Bestimmung des Harzes in den Harzseifen

Ohne Zusammenfassung     

Characterization and cytotoxicity studies of thiol‐modified polystyrene microbeads doped with [{Mo6X8}(NO3)6]2– (X = Cl,Br, I)

Halide octahedral molybdenum clusters [{Mo₆X₈}L₆]^n– possess luminescence properties that are highly promising for biological applications. These properties are rather dependent on the nature of both the inner ligands X (i.e. Cl, Br, or I) and the apical organic or inorganic ligands L. Herein, the luminescence properties and the toxicity of thiol‐modified polystyrene microbeads (PS‐SH) doped with [{Mo₆X₈}(NO₃)₆]^2– (X = Cl, Br, I) were studied and evaluated using human epidermoid larynx carcinoma (Hep2) cell cultures. According to our data, the photoluminescence quantum yield of {Mo₆I₈}@PS‐SH is significantly higher (0.04) than that of {Mo₆Cl₈}@PS‐SH (<0.005) and {Mo₆Br₈}@PS‐SH (<0.005). Treatment of Hep2 cells with {Mo₆X₈}@PS‐SH showed that all three types of doped microbeads had no significant effect on the viability and proliferation of the cells. Copyright © 2016 John Wiley & Sons, Ltd.     

The search for a potentially prebiotic synthesis of nucleotides via arabinose-3-phosphate and its cyanamide derivative

For the RNA world hypothesis to be accepted, the constitutional self-assembly of RNA will have to be demonstrated. Conceptually, the simplest route to RNA involves nucleotide polymerisation. Activated pyrimidine nucleotides can be derived from arabinose-3-phosphate under potentially prebiotic conditions, but the prebiotic synthesis of this sugar phosphate has not hitherto been investigated. The results of synthetic approaches involving phosphorylation, phosphate migration and 2,3-C--C bond construction are described herein.