Convex-transitivity and function spaces

It is shown that if X is a convex-transitive Banach space and 1p<∞, then L^p([0,1],X) and are convex-transitive. Here is the closed linear span of the simple functions in the Bochner space L^∞([0,1],X). If H is an infinite-dimensional Hilbert space and C₀(L) is convex-transitive, then C₀(L,H) is convex-transitive. Some new fairly concrete examples of convex-transitive spaces are provided.     

Fabrication,characterization and evaluation of bacterial cellulose-based capsule shells for oral drug delivery

Bacterial cellulose (BC) was investigated for the first time for the preparation of capsule shells for immediate and sustained release of drugs. The prepared capsule shells were characterized using X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. The BC capsule shells were studied for drug release using an USP type-I dissolution apparatus. Irrespective of the drying method and the thickness of the BC sheet, the capsule shells displayed an immediate drug release profile. Moreover, the addition of release-retardant cellulosic polymers sustained the drug release having first-order kinetics for hydroxypropylmethylcellulose and carboxymethyl cellulose sodium with R ² values of 0.9995 and 0.9954, respectively. Furthermore, these capsules shells remained buoyant in 0.1 N HCl (pH 1.2) solution up to 12 h. This study showed that BC is a promising alternative to gelatin capsules with both immediate and sustained drug release properties depending upon the compositions of the encapsulated materials.     

(1S,2R,2′S)‐ and (1S,2S,2′S)‐1‐phenyl‐2‐phenyl­thio‐2‐(tetra­hydro­pyran‐2′‐yl­thio)­ethanol diastereoisomers at 193 K

In the synthesis of 1‐phenyl‐2‐phenyl­thio‐2‐(tetra­hydro­pyran‐2‐yl­thio)­ethanol, C₁₉H₂₂O₂S₂, four diastereoisomers are formed. Two non‐centrosymmetric enantiomeric forms which crystallize in space groups P2₁2₁2₁ and Pna2₁ are presented. The former has an intramolecular hydrogen bond between the hydroxyl group and the O atom of the tetra­hydro­pyran ring. In the latter isomer, the hydroxyl group forms an intermolecular hydrogen bond to the O atom of the tetra­hydro­pyran­yl group of a neighbouring mol­ecule, joining the mol­ecules into chains in the c‐axis direction; the O?O distances are 2.962 (4) and 2.764 (3) Å, respectively. The tetra­hydro­pyran rings are in chair conformations in both isomers and the S side chain has an equatorial orientation in the former, but an axial orientation in the latter mol­ecule.     

Two 9‐alkylthiophenanthrenes at 193 K (alkyl = dodecyl and tetradecyl)

Two isostructural 9‐thiophenanthrene derivatives, 9‐dodec­ylthiophenanthrene, C₂₆H₃₄S, (I), and 9‐tetradecylthiophen­anthrene, C₂₈H₃₈S, (II), are reported. They crystallize in the monoclinic space group P2₁/c with four molecules in a unit cell. The S—C_phenanthrene bonds are 1.767 (2) and 1.772 (4) Å and S—C_alkyl bonds are 1.809 (2) and 1.804 (4) Å for (I) and (II), respectively. The bond angles at S are 104.04 (11) and 104.0 (2)° for (I) and (II), respectively.     

Di‐9‐anthryl disulfide at 193 K

The title compound, C₂₈H₁₈S₂, crystallizes in the monoclinic space group P2₁/n and the structure shows pseudosymmetry close to the space group C2/c. At 193 K the compound has a long S—S bond of 2.1089 (12) Å and the S atom to anthracene bond distances are 1.776 (3) and 1.770 (2) Å. The C—S—S—C torsion angle is 76.06 (13)°.     

An anthracene dimer with a fused 1,3‐dithiole ring at 193 K

The first butterfly‐shaped anthracene dimer including S atoms,8,9‐di­hydro‐3a,8[1′,2′]:9,13b[1′′,2′′]­di­benzeno­dibenzo­[3,4:7,8]cyclo­octa­[1,2‐d]‐1,3‐di­thiole, C₂₉H₂₀S₂, contains an exceptionally long Csp³—Csp³ bond of 1.672 (2) Å in the fused 1,3‐di­thiole ring. The length of the other bond bridging the anthracene moieties is 1.604 (3) Å.     

A novel particle sampling system for physico-chemical and toxicological characterization of emissions

Several studies have shown that combustion-derived fine particles cause adverse health effects. Previous toxicological studies on combustion-derived fine particles have rarely involved multiple endpoints and a detailed characterization of chemical composition. In this study, we developed a novel particle sampling system for toxicological and chemical characterization (PSTC), consisting of the Dekati Gravimetric Impactor (DGI) and a porous tube diluter. Physico-chemical and toxicological properties of the particles emitted from various combustion sources were evaluated in two measurement campaigns. First, the DGI was compared with the High-Volume Cascade Impactor (HVCI) and to the Dekati Low-Pressure Impactor (DLPI), using the same dilution system and the same sampling conditions. Only small differences were observed in the mass size distributions, total particulate matter (PM), and particulate matter with diameter smaller than 1 um (PM(1)) concentrations and geometric mass mean diameters (GMMD) between these three impactors. Second, the PSTC was compared with the HVCI sampling system, which has been optimal for collection of particulate samples for toxicological and chemical analyses. Differences were observed in the mass size distributions, total PM and PM(1) emissions, and GMMDs, probably due to the different sampling and dilution methods as well as different sampling substrates which affected the behavior of semi-volatile and volatile organic compounds. However, no significant differences were detected in the in vitro measurements of cytotoxicity between the samples collected with the PSTC and the HVCI systems. In measurements of genotoxicity, significant differences between the two sampling systems were seen only with the particles emitted from the sauna stove. In conclusion, due to compact size, PSTC is an applicable method for use in particle sampling as part of the toxicological and chemical characterization of particulate emissions from different combustion sources. It offers some advantages compared to the previously used high-volume sampling methods including compactness for field measurements, simple preparation of sample substrates and high extraction efficiency.     

Strong Axial Preference of 2-S Substituents in 3,4-Dihydro-2 H -1-Benzopyrans

The synthesis and crystal structure of a O,S,S-acetal derivative (1 R *,2 R *,2' S *)-1-(3,4-dihydro-2 H -1-benzopyran-2-ylthio)-2-phenyl-1-phenylthiopropan-2-ol 4 are reported. The 2-S-sidechain orientation in solution determined by OCHS signals in 1 H NMR spectra is mainly axial in all the 3,4-dihydro-2 H -1-benzopyran derivatives. Compound 4 crystallizes in the triclinic space group P 1 with an axial 2-S-sidechain and an intramolecular hydrogen bond between the OH and the ether oxygen with the O;;;O distance of 2.799(3) Å.