Interaction of salicylic acid with verrucae assessed by FT-Raman spectroscopy

FT-Raman spectroscopy has been used to investigate treated verrucae (warts from the sole of the foot) with a local application of a salicylic acid paint. Differences in the molecular structure of the stratum corneum across the verruca sample were observed, and by comparison with normal and hyperkeratotic skin it was concluded that the tissue around the edges of the verrucae was typically hyperkeratotic skin. In the centre of the verruca, the molecular structure of the skin was altered showing evidence of the interaction with salicylic acid. Salicylic acid was not observed in its characteristic dimerised acid structure, but spectroscopic evidence suggested that fission of the intermolecular H-bonding essentially cleaved the dimer. Observed changes in the v(CCO) stretching mode of the carboxyl and hydroxyl groups indicate the inter H-bonds have broken. These spectral changes are believed to be more consistent with salicylic acid bonding within the human papillomavirus-containing verruca tissue rather than simple acid dissociation upon dissolution in water within the tissue. No evidence for the presence of the other paint components, lactic acid and flexible collodion, was found in the verrucae spectra. This Raman approach may help to elucidate the molecular basis for therapeutic agents interacting with diseased skin.     

Crosslinked poly(hydroxyethyl methacrylate) membranes for desalination by reverse osmosis

A series of crosslinked hydroxyethyl methacrylate (HEMA) membranes for reverse osmosis desalination has been prepared. The crosslinkers used were trimethylol propane trimethacrylate (TPT) or ethylene glycol dimethacrylate (EGD). Membranes were synthesized by polymerizing the monomers as a thin homogeneous film. In addition to reverse osmosis tests, the membranes were also characterized by osmosis experiments and sorption measurements. The reverse osmosis water flux (1500 psi applied pressure, 4% NaCl brine, pH = 5) for these membranes decreases from 0.6 gallonmil/ft²-day (GMFD) to 0.055 GMFD and salt rejection increase from 78% to a maximum of 94% as the amount of TPT is increased from 0 to 11 mole-%. Water contents decrease from 42% to 15% over the same range of crosslinker, but the preferential sorption of water to salt does not vary. Thus, rises in reverse-osmosis semipermeability were found to result from changes in water–salt diffusivity ratios. The mechanism of permselectivity has been interpreted in terms of parallel diffusive fluxes across the membrane of primary H-bonded water and secondary water plus salt ions.     

Mössbauer effect emission spectroscopy and Auger electron spectroscopy study of the (111) Ni surface

Mössbauer effect emission spectroscopy (MEES) and Auger electron spectroscopy were combined in an ultrahigh vacuum system to study the ferromagnetic (111) Ni surface. Preliminary data on a strained and roughened surface with nearly a monolayer of contamination are presented. The MEES spectra show broad resonances arising from a distribution of hyperfine fields. With an oxygen coverage of 0.15 monolayer (ML), surface sites with magnetic hyperfine fields larger than that for bulk nickel account for 30% of the total resonant absorption area. Fields larger than 130 kG can account for 70% of the absorption area despite 0.4 ML of carbon coverage. With 0.5 ML oxygen coverage the average hyperfine field is greatly increased.     

Interaction of estradiol and LHRH on LH release in rhesus females: evidence for a neural site of action

The effects on LH release of infusing luteinizing hormone-releasing hormone (LHRH 80 mug/20 min) into the third ventricle, the pituitary, and the peripheral circulation were compared in spayed rhesus monkeys. Within 30 min after iv administration, serum LH concentrations increased to twice to preinfusion levels, and by 120 min declined to original values. Intraventricular or intrapituitary infusions of LHRH resulted in similar LH increments, but the peaks occurred somewhat later (70 to 90 min) and the elevations persisted beyond 200 min. Estradiol-17beta (E2) administered by a sc silastic capsule caused a 5-fold increase in serum E2 within 1 h and reduced serum LH levels by 65% within 4 h. The LH release caused by intrapituitary LHRH was significantly suppressed by maintaining for 72 h E2 concentrations near 100 pg/ml, a level inadequate for stimulating an LH surge. A comparable E2 treatment before intraventricular infusion of LHRH, however, did not inhibit LH release. This difference between the effects of intrapituitary and intraventricular LHRH was demonstrable only in E2-treated monkeys. Moreover, the release of LH after intraventricular infusion of LHRH in E2-treated females was blocked (P less than 0.001) by a single iv injection (90 min before LHRH) of haloperidol (1 mg/kg BW) or phentolamine (5 mg/kg), but was not altered by phenoxybenzamine (3 mg/kg) or propranolol (5 mg/kg). Without E2 pretreatment, LH release after intraventricular LHRH was enhanced by each drug. Phentolamine, injected into both E2- and non-E2-treated monkeys 90 min before an intrapituitary infusion of LHRH had no demonstrable effects on the patterns of serum LH. Our interpretation of these data is that E2 at a concentration below the level that triggers an LH surge has a dual action on LHRH-induced LH release in monkeys: an inhibitory effect exerted directly on the pituitary and a stimulatory effect on the brain. Furthermore, the paradoxical effects of the drugs with and without E2 are due to the involvement of two distinct neuronal systems. The postulated neural effects of both E2 and these drugs can be explained either by an increase in the quantity of injected or secreted LHRH which ultimately binds to LH-secreting cells or by the release of additional endogenous LH-stimulating agents together with ventricular LHRH.     

Histological and functional studies of small intestinal mucosa in intestinal tuberculosis

Twelve cases of peptic ulcer with diabetes mellitus were found in 165 hospitalized diabetics. All of them had gastric ulcer and no duodenal ulcers were found. The incidence of peptic ulcer in diabetics was comparatively higher than the previously reported series. But there was nosignificant correlation between the duration of diabetes and the onset of gastric ulcer. The gastric ulcer with poorly controlled diabetes showed more intractability than those without triopathy and well-controlled diabetes.     

The oxidation of ortho-xylene on vanadium pentoxide catalysts II. The influence of catalyst support material on product distribution

The oxidation of o-xylene has been investigated on a number of commercial vanadia catalysts in an isothermal packed bed reactor. The data show that phthalic anhydride selectivities of up to 85 mol percent can be obtained on titania supported catalysts whereas maximum values of around 30 mol percent are achieved on silica supported catalysts. An attempt at modelling the kinetics of the reactions using the Redox mechanism is reported. The results indicate that this model is not adequate to fully describe all reactions. Some of the difficulties are indicated and suggestions are made for modifications to the models along with directions for future work.     

The oxidation of ortho-xylene on vanadium pentoxide catalysts. I. Transient kinetic measurements

The gas-phase oxidation of o-xylene was studied on commercial vanadia oxidation catalysts, one supported on silica the other on titania. Kinetic data were obtained under transient and steady-state conditions in fixed bed and transported bed reactors. Product distributions and rates of conversion were measured in the temperature range 233°C and 390°C. The transient experiments with these catalyst indicate a dramatic decrease in catalyst activity with time, accompanied by a considerable decrease in selectivity to phthalic anhydride and an increase in selectivity to carbon oxides. These data also provide additional support for a two-step reaction model. The object of this experimental program is to study the kinetics of oxidation of o-xylene on vanadium pentoxide catalysts and thereby elucidate the mechanisms of the reaction and some of its characteristics.