Analysis and quantification of parabens in cosmetic products by utilizing hollow fibre-supported liquid membrane and high performance liquid chromatography with ultraviolet detection

A simple and direct method based on hollow fibre-supported liquid membrane (HFSLM) extraction and liquid chromatography equipped with a UV detector was developed for analysis and quantification of parabens in cosmetic products. The parabens analysed included methyl, ethyl, propyl, isobutyl and butyl paraben. The HFSLM extraction was carried out by employing di- n -hexyl ether as organic liquid that was immobilized in the hollow fibre membrane. The HFSLM extraction is simple, cheap, minimizes the use of solvents and uses disposable material. In an investigation of 11 paraben-containing cosmetic products, the levels of parabens (sum of all parabens in a product) ranged from 0.43% to 0.79% (w/w) for skin care products, 0.07–0.44% for hair fixing gels and 0.30–0.52% for soap solutions. The levels of individual parabens in individual cosmetic products ranged between 0.03% and 0.42% w/w for skin care products, 0.07% and 0.26% w/w for hair fixing gels and between 0.11% and 0.34% w/w for soap solutions. Parabens were found in the highest concentrations in skin care products followed by soap solutions and the least amounts were found in hair fixing gels. Of the paraben-containing products tested, all of them contained methyl paraben and about 90% contained propyl paraben in addition to methyl paraben. One product contained all the parabens analysed.     

A capillary fluorescence standard for microfluorometry

Quartz glass capillaries of about 6 μm inside diameter were filled with fluorochrome solutions of accurately known concentrations and embedded as microscopical objects. The fluorescence intensity of a constant capillary volume has been found to be directly proportional to the amount of the excited fluorochrome in this volume within the fluorochrome concentration range 1:10³. The capillary volume can be determined accurately by microinterferometric measurement of the inside diameter. The capillary section irradiated by the exciting light may be considered as very small in comparison with the total length of the capillary tube. During and after irradiation the excited part of fluorochrome solution is continuously renewed by convectional flow and diffusion. Therefore photodecomposition does not affect the measured fluorescence intensity, and the standard value remains unchanged even after numerous measurements. Thus, these fluorescence standards may be used to make successive calibrations of a microfluorometer and to check the constancy and reproducibility of measuring conditions. In certain circumstances it also permits measured fluorescence intensity to be interpreted in terms of the amount of fluorochrome or fluorescent substance. The results achieved with the capillary fluorescence standard are compared with those obtained by means of conventional methods. In addition, some essential optical properties of the microfluorometer equipment required for the proper use of this standard are discussed.     

Thromboxane synthase expression in renal transplant patients with rejection

Thromboxane synthase (TS) catalyzes the formation of thromboxane (TxA2) in monocytes/macrophages, platelets, and various tissues. TxA2 is likely to play a role in graft dysfunction due to its vasoconstrictive and platelet aggregatory properties. We studied the expression of TS in 7 normal native kidneys, 29 consecutive renal allograft biopsies (performed for rising serum creatinine, n = 23, and delayed graft function, n = 6), and one transplant nephrectomy specimen with severe acute rejection. TS expression was determined by immunocytochemistry using a monoclonal antibody against human TS, Kon-7. Histologic grading of the transplant biopsy specimens was based on the Banff classification. The degree of TS staining was graded in the glomeruli, interstitium, tubules and vessels from 0 to 3+. Of 29 biopsies, 13 had chronic nephropathy (CN), 6 had acute rejection (AR) with chronic nephropathy (AR/CN), 4 had acute rejection (AR), and 6 had acute tubular necrosis (ATN). TS staining of native kidneys showed sporadic interstitial cells. The biopsy and transplant nephrectomy specimens showed significant staining, predominantly in the glomeruli and interstitium. Positively staining cells appeared to be of macrophage/monocyte lineage by morphology. The mean glomerular staining grade was significantly increased in specimens with AR (2.3 +/- 0.9) and the mean interstitial staining was increased in specimens with AR/CN (2.2 +/- 0.9). Follow-up renal function 6 months post-biopsy showed that patients with higher TS staining grades had a faster decline in graft function. In conclusion, TS expression is increased in patients with acute rejection with or without chronic nephropathy and is associated with more rapid deterioration in function.     

Étude de l'absorption optique de couches minces de fluorure de magnésium et de fluorure d'aluminium en fonction de leurs conditions de préparation

An investigation of the optical absorption of thin films of magnesium fluoride and of aluminium fluoride obtained by evaporation was performed for the energy range 1.5–12 eV. A previous study by nuclear analysis had shown the influence of the conditions of preparation on the composition of the layers; in particular the content of Na in parts per thoudand of the basic metal varied from 10^-1 to 20.For these two fluorides, we note a first optical gap below 10.95 eV which is strongly dependent on the degree of crystallisation and on the composition of the layers, and which corresponds to transition states between F^- and Na⁺. For a high sodium concentration an absorption band appears at 6.5 eV; it can be interpreted in terms of transitions between OH^- and Na⁺ in inclusions of NaMgF_3?x(OH)_x (or NaAlF_4?x(OH)_x). If tantalum crucibles are used the presence of TaO₂F in the layers can be observed and the absorption edge in this case is at 5.6 eV. It was also noted that for a disordered structure or for a large concentration of impurities the absorption presents a long exponential tail that can be interpreted in terms of a superposition of different mechanisms.     

Spectroscopic investigations of gamma-ray irradiation effects on metal organic framework

Journal of Materials Science - The chemical and physical features of metal organic frameworks (MOFs) at a molecular level are of great merit to understand structure–property relationships...     

Experiments and identification in micro powder injection moulding from stainless steel powder 5μm size

Research tasks at ENSMM/LMA are focused on the development of mixtures of very fine powders associated to polymer binders dedicated to the powder injection micro-moulding (μPIM) in accordance with many works already carried out with different feedstock suppliers dedicated to the macrocomponents. Other research parts are the measurement of the shrinkage rate for cylindrical specimen in dilatometer during sintering stage and the beam bending tests during sintering process for to determine the viscosity of the sintered parts at high temperatures. It is important work to identify the constitutive law in a thermo-elasto-viscoplastic sintering model for the prediction of the shrinkage, relative density, the final residual stress and the deformation of the micro components.     

Fabrication of concave and convex potassium bromide lens arrays by compression molding

A new simple and cost-effective method has been developed for the fabrication of both plano-convex and plano-concave lens arrays with potentially important sag heights. The process is based on the use of potassium bromide (KBr) powder. At ambient temperature and under pressure, KBr powder is compressed on a molding die with the desired shape to form a solid lens array. The quality of the lens arrays has been assessed, and we present the first image produced by a converging KBr lens array.     

Epidemiology of S. aureus cross-infections in dermatological wards

Over a three-year period, 196 of 3115 patients admitted in a dermatological department became infected with S. aureus (6,2 %). 205 strains of S. aureus were isolated. Serologic typing, phage-typing and antibiotic sensitivity tests revealed 3 epidemic and 2 endemic strains. The 3 epidemic strains infected 24 patients: 12 from july to november 1972 were infected with a serotype 66438 S. aureus resistant to fusidic acid. 6 patients (male) were infected with a serotype III in february and march 1972; 8 patients were contaminated with a serotype 18 S. aureus from december 1973 to february 1974, after staying in a surgical department. Of the 2 endemic strains 1, phage-pattern 53/79, is non-typable by serologic-typing; this strain has been observed only in the dermatological department and 20 patients were infected with, from january to october 1974. The second endemic strain, phage-pattern 81/+ serotype I, cross-infected 16 patients during this three-year survey; 12 of them were admitted repeatedly. During this three-year survey, it could be proved that, at least, 1 out of 3 patients is infected with an epidemic or an endemic strain. We can suggest that the factors enhancing cross-infection in dermatological department are: the sex of patients (80 % were male); presence of a tween splitting enzyme by S. aureus promotes growth of Staphylococci on the skin; patients transfered from a department to another or repeatedly admitted are more often infected. But, as they are source of some outbreaks, they need special measures (asepsis and hygiene); cortico?ds or immunodepressors enhance cross-infection; antibiotics must not be only limited but varied too.     

Carbonylation of Formaldehyde with Zeolite Catalysts

Carbonylation of formaldehyde with carbon monoxide over zeolite catalysts has been investigated. Compared with resins (Amberlyst-15 and Amberlyst-70), and phosphotungstic acid, the zeolite catalysts especially ZSM-5 showed very high selectivity to methyl glycolate. The selectivity of ZSM-5 was maintained to high temperature up to 200 °C.