1.A ring closing metathesis strategy for carbapyranosides of xylose and arabinose.
Mattis CE1, Mootoo DR2. Carbohydr Res. 2016 Apr 29;425:43-7. doi: 10.1016/j.carres.2016.03.002. Epub 2016 Mar 16.
The synthesis of β-carba-xylo and arabino pyranosides of cholestanol is described. The synthetic strategy, which is analogous to the Postema approach to C-glycosides, centers on the ring closing metathesis of an enol ether-alkene precursor to give a cyclic enol ether that is elaborated to a carba-pyranoside via hydroboration-oxidation on the olefin. The method, which is attractive for its modularity and stereoselectivity, may find wider applications to carba-hexopyranosides and other complex cycloalkyl ether frameworks.
2.Assessment of oral malodor and tonsillar microbiota after gargling with benzethonium chloride.
Iwamura Y1, Hayashi J, Sato T, Sato S, Murakami T, Fujimura T, Sasaki Y, Okada K, Takahashi E, Kikuchi T, Aino M, Noguchi T, Shimazaki Y, Mitani A, Fukuda M. J Oral Sci. 2016;58(1):83-91. doi: 10.2334/josnusd.58.83.
The oropharyngeal area can be a source of halitosis. However, the relationship between healthy tonsillar microbiota and halitosis is poorly understood. We conducted a pilot clinical study to clarify the effect of gargling with an antiseptic agent on tonsillar microbiota in patients with halitosis. Twenty-nine halitosis patients who did not have otolaryngologic disease or periodontitis were assigned randomly to one of three groups: benzethonium chloride (BZC) gargle; placebo gargle; no gargle. Concentrations of volatile sulfur compounds (VSCs) in mouth air, the organoleptic score (ORS) and tongue-coating score (TCS) were measured before and after testing. Tonsillar microbiota were assessed by detection of periodontal pathogens, and profiling with terminal-restriction fragment length polymorphism (T-RFLP) analysis and sequencing of 16SrRNA clone libraries for taxonomic assignment. Gargling with BZC reduced the concentrations of methyl mercaptan and hydrogen sulfide and the ORS, but did not affect the TCS or prevalence of periodontal pathogens.
3.Ammonium sulfide-assisted hydrothermal activation of palygorskite for enhanced adsorption of methyl violet.
Tian G1, Wang W2, Kang Y2, Wang A3. J Environ Sci (China). 2016 Mar;41:33-43. doi: 10.1016/j.jes.2015.03.036. Epub 2015 Jul 26.
Herein, palygorskite (PAL) was activated via a simple hydrothermal process in the presence of ammonium sulfide, and the effects of activation on the microstructure, physico-chemical feature and adsorption behaviors of PAL were intensively investigated. The hydrothermal process evidently improved the dispersion of PAL crystal bundles, increased surface negative charges and built more active -Si-O(-) groups served as the new "adsorption sites". The adsorption property of the activated PAL for Methyl Violet (MV) was systematically investigated by optimizing the adsorption variables, including pH, ionic strength, contact time and initial MV concentration. The activated PAL exhibited a superior adsorption capability to the raw PAL for the removal of MV (from 156.05 to 218.11mg/g). The kinetics for MV adsorption followed pseudo second-order kinetic models, while the isotherm and thermodynamics results showed that the adsorption pattern well followed the Langmuir model.
4.Mucosal acidification increases hydrogen sulfide release through up-regulating gene and protein expressions of cystathionine gamma-lyase in the rat gastric mucosa.
Mard SA1, Veisi A2, Ahangarpour A2, Gharib-Naseri MK2. Iran J Basic Med Sci. 2016 Feb;19(2):172-7.
OBJECTIVES: This study was performed to investigate the effects of mucosal acidification on mRNA expression and protein synthesis of cystathionine gamma lyase (CSE), cystathionine beta synthase (CBS), and mucosal release of H2S in gastric mucosa in rats.