Vacuum ultraviolet laser‐induced fluorescence kinetic study of the reactions of Cl atoms with fluoroalkenes (CxF2x+1CHCH2, x = 1,2,4, 6, and 8) at low pressures

Pulsed laser photolysis/vacuum ultraviolet laser‐induced fluorescence techniques were used to measure rate coefficients for Cl atom reactions with a series of fluoroalkenes (C_xF_2x+1CH?CH₂, x = 1,2,4,6,8) in 6–10 Torr of CF₄ diluent at 295 ± 2 K. Rate coefficients (units of 10^?11 cm³ molecule^?1s^?1) of 4.49 ± 0.64, 6.58 ± 0.59, 8.91 ± 0.58, 9.27 ± 0.64, and 9.00 ± 0.87 were determined for C_xF_2x+1CH?CH₂ with x = 1,2,4,6, and 8, respectively. In 6–10 Torr of CF₄ diluent, the kinetics of the title reactions are at, or near, the high‐pressure limit for x = 4, 6, and 8, approximately 30% below the high‐pressure limit for x = 2, and approximately 50% below the high‐pressure limit for x = 1. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 328–332, 2007     

Real-time analysis of secondary organic aerosol particles formed from cyclohexene ozonolysis using a laser-ionization single-particle aerosol mass spectrometer.

A real-time analysis of secondary organic aerosol (SOA) particles formed from cyclohexene ozonolysis in a smog chamber was performed using a laser-ionization single-particle aerosol mass spectrometer (LISPA-MS). The instrument obtains both size and chemical compositions of individual aerosol particles with a high time-resolution (approximately 2 s at the maximum). Both positive and negative-ion mass spectra are obtained. Standard particles generated from dicarboxylic acid solutions using an atomizer were also analyzed. For both standard and SOA particles, the negative-ion mass spectra provided information about the molecular weights of the organic compounds in the particles, since the intense ions in the negative-ion mass spectra are mainly attributable to the molecular-related ions [M-H]-. It was demonstrated that the real-time single-particle analysis of SOA particles by the LISPA-MS technique can reveal the formation and transformation processes of SOA particle in smog chambers.     

The birch reduction of heterocyclic compounds V Birch reduction of 2‐ and 5‐acylfuran‐3‐carboxylic acids and reductive elimination of 2‐(arylmethoxymethyl)furan‐3‐carboxylic acids

The Birch reduction of 2‐ and 5‐acylfuran‐3‐carboxylic acid 1 and 4 gave 2‐acyl‐2,3‐dihydrofuran‐3‐carboxylic acid 2 and 5‐acyltetrahydrofuran‐3‐carboxylic acid 5 , respectively. Further examination of the reductive elimination was also studied on 2‐(arylmethoxymethyl)furan‐3‐carboxylic acids 7.     

Structures, biological activities, and total syntheses of 13-hydroxy- and 13-acetoxy-14-nordehydrocacalohastine, novel modified furanoeremophilane-type sesquiterpenes from Trichilia cuneata

[reaction: see text] 13-Hydroxy-14-nordehydrocacalohastine (2) and 13-acetoxy-14-nordehydrocacalohastine (3), two novel modified furanoeremophilane-type sesquiterpenes isolated from Trichilia cuneata, showed inhibitory activities for membrane lipid peroxidation in mitochondria and microsomes. The first, highly convergent total syntheses of new compounds 2 and 3 have also been achieved via a palladium-mediated three-component coupling reaction between 2-iodotoluene (7), 1-penten-4-yn-3-ol (8), and diethyl ethoxymethylenemalonate (9).     

Interaction between phospholipid vesicular structures with long chain zwitterionic surfactants

Solubilization of different zwitterionic phospholipid vesicles structures such as L--phosphatidylcholine (PC) and 1,2-didecanoyl-sn-glycero-3-phosphocholine (DPC) have been studied in aqueous bulk by using zwitterionic surfactant dimethylhexadecylammoniopropanesulfonate (HPS). This has been done by studying the aggregation of HPS in pure water and in the presence of 7–36 M of fixed concentrations of each lipid with the help of pyrene fluorescence intensity (I ₁/I ₃) measurements. The fluorescence measurements showed that HPS monomers undergo two kinds of aggregation process, which were identified by the three breaks in a plot of pyrene fluorescence versus HPS concentration. The first two breaks, C ₁ and C ₂, indicate the onset and completion of vesicle solubilization respectively, upon incorporation of HPS monomers into the vesicles and led to solubilization in the form of mixed micelles. This process was not clearly visible at low lipid concentration. We evaluated the partition coefficient (K), which defines the degree of partitioning of surfactant monomers into the vesicles with respect to the aqueous medium. A high K value of HPS-lipid aggregates indicates the stronger interactions between surfactant and lipid vesicles. The K values evaluated for PC and DPC are quite close to each other, which indicates that K values were independent of phospholipid chain length.     

MOON for neutrino-less double beta decays

The MOON (Majorana/Mo Observatory Of Neutrinos) project aims at studies of the Majorana nature of the neutrino (ν) and the ν-mass spectrum by spectroscopic experiments of neutrino-less double beta decays (0νββ) with the ν-mass sensitivity of 〈m _ν ^m 〉 = 100−30 meV. The solid scintillator option of the MOON detector is a super ensemble of multi-layer modules, each being composed by PL scintillator plates and position-sensitive detector planes with good overall energy resolution of σ ≈ 2% at the Q _ββ ≈ 3 MeV. Thin ββ source films are interleaved between the detector planes. High localization of the two β tracks enables one to select true signals and reject BG ones. The multi-layer structure of the detector makes it realistic to build a compact ton-scale detector. MOON with detector ≠ ββ source is used for studying 0νββ decays from ¹⁰⁰Mo, ⁸²Se and other ββ isotopes with large Q _ββ . Real-time exclusive measurements of low energy solar neutrinos can be made by observing inverse β rays from solar-ν captures of ¹⁰⁰Mo in delayed coincidence with the subsequent β decay of ¹⁰⁰Tc.