Structure of sodium alkyl sulfate micelles

Apparent and partial molar volumes of aggregated sodium octyl-, decyl-, dodecyl-, and tetradecyl sulfate molecules have been determined rigorously in terms of the pseudophase separation model. Mass density inside the micellar core—a basic thermodynamic parameter in the research of micelles by nuclear techniques—has been derived from the partial molar volumes.Micellar aggregation numbers of the same surfactants, obtained from small-angle neutron scattering [SANS] by systematically varying the surfactant concentration and solution temperature are published. A survey is given of the physical models and evaluation algorithms applied in SANS, together with a critical comparison of available experimental data published by various research teams.By utilizing a new least-squares fitting algorithm based on a microscopic diffusion model, the formation and annihilation parameters of ortho-positronium Co-Ps) in the micellar pseudophase and in the aqueous solvent, as well as the o-Ps diffusion coefficient in the solvent are deduced by evaluating conventionally measured positron lifetime spectra. From the pickoff annihilation rate of o-Ps in micelles the surface tension of the micellar core around the solubilization site of o-Ps is calculated. SANS results are utilized to determine the diffusion coefficient of o-Ps in normal and in 99.85% heavy water as a function of temperature. A definite isotopic effect in the two solvents can be seen from the results obtained for the diffusion coefficient and its activation energy. The Arrhenius plot of o-Ps diffusion coefficients indicates that o-Ps diffuses in both media without tunnelling.     

Reference material “total protein in human urine”

Two batches of a reference material (RM) “total protein in human urine” were prepared for quality assurance in the determination of human urinary proteins. The material was prepared by freeze-drying of a pooled urine sample obtained from healthy volunteers. Protein concentrations in both batches were within physiological values, close to their upper limit. Interlaboratory comparisons conducted in 26 laboratories using the standard operation procedures elaborated for six of the most frequently employed methods (biuret, Bradford, Exton, Lowry, Pesce, and Watanabe) revealed that the results obtained by the individual methods were significantly different due to various reaction mechanisms involved. It was therefore necessary to certify the mean values and their uncertainties individually for each method. These operationally defined certified or information values are valid only when the prescribed standard operation procedures are strictly followed.     

Phosphorylated Acid Anilides as New Insecticides

Abstract

Some new phosphorodithioates containing acid anilide-group have been synthesized and the relationship between insecticidal activity and the structure of the compounds has been studied.     

Easy and efficient deracemization of all trans-1,3-diphenyl-2,4-bis-[α-hydroxybenzyl]-cyclobutane and its bisphenylsulfanyl derivative and the assignment of the absolute configuration

An effective deracemization of all trans-1,3-diphenyl-2,4-bis-[α-hydroxybenzyl]-cyclobutane 1 was achieved by the application of the (R)-(?)-O-acylmandelic acid as a resolving agent, followed by the crystallization of the diastereomeric esters. The kinetic resolution was also observed in the esterification. Racemic 1 was transformed into bisphenylsulfanyl derivative 3. Enantioselective oxidation of 3 with a VO(acac)₂-chiral Schiff Base catalytic system led to a kinetic resolution, and highly enantiomerically enriched bissulfides/bissulfoxides were isolated. Assignment of the absolute configuration was made by spectroscopic methods and chemical correlation. Due to the rigid C₂-symmetric framework, chiral compounds 1 and 3 have strong steric requirements and may be useful in chiral recognition.     

Enzyme-catalyzed synthesis of (R)- and (S)-3-hydroxy-3-(10-alkyl-10H-phenothiazin-3-yl)propanoic acids

Starting from the racemic ethyl 3-hydroxy-3-(10-alkyl-10H-phenothiazin-3-yl)propanoates as substrates, a multienzymatic procedure was developed for the efficient synthesis of the corresponding highly enantiomerically enriched (R)- and (S)-3-heteroaryl-3-hydroxypropanoic acids.     

Dielectric properties and thermal stability of γ-irradiated inorganic nanofiller modified PVC

The dielectric characteristics of polyvinyl chloride nanocomposites containing titania, silica and alumina at the concentration of 5% were investigated by dielectric spectroscopy. The sharp modification in the permittivity and dielectric loss of neat and irradiated PVC samples over the low frequency range may be explained by the interaction between external electrical field and the dipoles formed during high energy exposure. The material characterization is completed by the thermal stability assay based on the accumulation of carbonyl units in the sample matrices, which provides the differences in the molecular level contact between host polymer and fillers.     

The effect of different workplace nanoparticles on the immune systems of employees

Currently, nanoparticles are widely present in the environment and are being used in various industrial technologies. Nanoparticles affect immune functions, causing different immune responses. The aim of the current study was to evaluate several cytokines, interleukin (IL)-1b, IL-6, IL-8, tumour necrosis factor-a (TNF-α), interferon-γ, adhesive molecule sICAM-1, macrophage inhibitory protein 1a (MIP1a) and secretory immunoglobulin A, in nasal lavage fluid and in the peripheral blood of healthy subjects exposed to workplace nanoparticles. Thirty-six employees from three different environments were examined: 12 from a metalworking company, 12 from a woodworking company and 12 office workers. The nanoparticles in the different workplaces were detected in the air in the immediate vicinity of the employees. The particle number concentration and surface area values were significantly higher in the workplaces of the metal- and woodworking industries, but concentrations of mass were lower (the measurements were performed by an electrical low-pressure impactor ELPI+). Energy dispersive X-ray spectroscopy (EDS, an attachment to a high-resolution SEM) was used to provide elemental analysis or chemical characterization of the dust particles in a low-vacuum field-free mode operating at a potential of 15 kV spot 3.0. The technique used provided quantitative and spatial analyses of the distribution of elements through mapping (two to three parallel measurements) and point analysis (four to five parallel measurements). Samples from the metal industry contained more ultramicroscopic and nanometric particles, e.g. toxic metals such as Zn, Mn and Cr, and fewer microscopic dust particles. The nasal lavage and peripheral blood were taken at the beginning and the end of the working week, when immune indices were measured. Our data showed a statistically significant increased level of the pro-inflammatory cytokine TNF-α in serum in both exposed groups compared with office workers as well as a higher level of TNF-α in workers from the woodworking company compared with the metalworking employees. We found an elevated level of IL-6 in the exposed groups as well as an elevated level of IL-8 in the nasal lavage in woodworking employees after work.     

The crystal and molecular structure of sodium 4‐(2,4,6‐triisopropylbenzoyl)benzoate in terms of the photochemical behaviour of the anion

Contrary to the known 4‐(2,4,6‐triisopropylbenzoyl)benzoate salts, di‐μ‐aqua‐bis[tetraaquasodium(I)] bis[4‐(2,4,6‐triisopropylbenzoyl)benzoate] dihydrate, [Na₂(H₂O)₁₀](C₂₃H₂₇O₃)₂·2H₂O, (1), does not undergo a photochemical Norrish–Yang reaction in the crystalline state. In order to explain this photochemical inactivity, the intermolecular interactions were analyzed by means of the Hirshfeld surface and intramolecular geometrical parameters describing the possibility of a Norrish–Yang reaction were calculated. The reasons for the behaviour of the title salt are similar crystalline environments for both the o‐isopropyl groups in the anion, resulting in similar geometrical parameters and orientations, and that these interaction distances differ significantly from those found in salts where the photochemical reaction occurs.     

Crystal Structures of N-(4-butyryl-3-hydroxyphenyl)acetamide Monohydrate and 4-(4-Chlorophenyl)-2-methyl-4-oxobutanoic Acid: Possibilities of Yang Photocyclization

Abstract  

N-(4-butyryl-3-hydroxyphenyl)acetamide monohydrate, (I), and 4-(4-chlorophenyl)-2-methyl-4-oxobutanoic acid, (II), are photochemically inert, which is a result of their conformation. The geometrical parameters describing the molecular conformation and possibilities of the Yang photocyclization in crystals have been calculated and discussed. Compound (I) forms double ribbons along the a axis, stabilized by hydrogen bonds and π⋯π interactions. Compound (II) forms dimers. (I): triclinic, space group \textP[`1] {\text{P}}\bar{1} , a = 6.9291(12) ?, b = 7.5736(16) ?, c = 13.0528(18) ?, α = 79.643(17)°, β = 85.818(15)°, γ = 63.97(2)°, Z = 2. (II): monoclinic, space group P2₁/c, a = 11.904(2) ?, b = 9.6508(12) ?, c = 10.666(2) ?, β = 110.64(2)°, Z = 4.