Combustion Processes as a Source of High Levels of Indoor Hydroxyl Radicals through the Photolysis of Nitrous Acid.

Hydroxyl radicals (OH) are known to control the oxidative capacity of the atmosphere but their influence on reactivity within indoor environments is believed to be of little importance. Atmospheric direct sources of OH include the photolysis of ozone and nitrous acid (HONO) and the ozonolysis of alkenes. It has been argued that the ultraviolet light fraction of the solar spectrum is largely attenuated within indoor environments, thus, limiting the extent of photolytic OH sources. Conversely, the ozonolysis of alkenes has been suggested as the main pathway of OH formation within indoor settings. According to this hypothesis the indoor OH radical concentrations span in the range of only 10(4) to 10(5) cm(-3). However, recent direct OH radical measurements within a school classroom yielded OH radical peak values at moderate light intensity measured at evenings of 1.8 × 10(6) cm(-3) that were attributed to the photolysis of HONO. In this work, we report results from chamber experiments irradiated with varying light intensities in order to mimic realistic indoor lighting conditions. The exhaust of a burning candle was introduced in the chamber as a typical indoor source causing a sharp peak of HONO, but also of nitrogen oxides (NOx). The photolysis of HONO yields peak OH concentration values, that for the range of indoors lightning conditions were estimated in the range 5.7 ×· 10(6) to 1.6 × 10(7) cm(-3). Excellent agreement exists between OH levels determined by a chemical clock and those calculated by a simple PSS model. These findings suggest that significant OH reactivity takes place at our dwellings and the consequences of this reactivity-that is, formation of secondary oxidants-ought to be studied hereafter.

Información y comunicación para pacientes externos con nutrición artificial / Information and comunication of outpatients with artificial nutrition

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Experimental confirmation of the dicarbonyl route in the photo-oxidation of toluene and benzene.

The methodology of solid phase microextraction (SPME) with O-(2,3,4,5,6)-pentafluorobenzylhydroxylamine hydrochloride (PFBHA) on-fiber derivatization for the determination of carbonyls has been applied to the photo-oxidation of benzene and toluene carried out in the EUPHORE chambers. This work focuses on the results obtained for a number of highly reactive carbonyls, crucial in the determination of branching ratios and confirmation of the carbonylic route. The observed yields and kinetic behavior were compared to simulations with the Master Chemical Mechanism model, version 3.1 (MCMv3.1). The following yields were measured in the toluene system: glyoxal, (37 +/- 2)%; methylglyoxal, (37 +/- 2)%; 4-oxo-2-pentenal, > (13.8 +/- 1.5)%; and total butenedial, (13 +/- 7)% (cis-butenedial, (6 +/- 3)%; trans-butenedial, (7 +/- 4)%]. For benzene, the experimental glyoxal yields were (42 +/- 3) and (36 +/- 2)% for the two successive experiments (September 24 and 25, 2003), (17 +/- 9)% for total butenedial [(8 +/- 4)% cis-butenedial and (9 +/- 5)% trans-butenedial (September 24, 2003)] and (15 +/- 6)% total butenedial (September 25, 2003) [(7 +/- 3) and (7 +/- 3)% for the cis and trans isomers, respectively]. PTR-MS estimations for butenedial also allowed the two isomers of butenedial to be distinguished, but the measurements showed signs of interference from other products. The results presented confirm the fast ring cleavage and provide further experimental confirmation of the dicarbonylic route.

Characterisation of absorptive sampling with SPME fibres in the EUPHORE photoreactor.

The implementation of an experimental set-up for sampling, and characterisation of parameters related to absorptive sampling solid phase microextraction (SPME) in the EUPHORE photoreactor is described. Toluene was taken as probe compound. Optimisation of the sampling and calibration curves are presented. Equilibrium was achieved in just 30s due to the good agitation in the chambers and the LOD was 0.24 ppbV. The precision was +/-0.02 expressed as relative standard deviation (n=9). The inter-fibre reproducibility was +/-0.03 expressed as relative standard deviation. The effect of the temperature and the sun radiation on absorption in the fibre is also studied using a relative method to calculate the ratio K/K(0) (ratio of absorption constants at two different times during the experiment at which temperature and radiation conditions experimented important variations) calculated through known parameters, avoiding in this way the need for external calibrations in the calculation of K. The results showed a difficult to predict dependence of absorption over the combination of temperature and sun radiation and the need to develop sampling systems with absorptive SPME in which sun radiation has no influence. The stability in different conditions of compounds absorbed in the fibre was also subject to study. At room temperature half of the compound absorbed is expected to desorb in 1.21 h. Conversely, when fibres were kept at low temperatures (-86 degrees C) after 21 days, desorption was negligible.

[Anomalous connection of inferior vena cava to left atrium: infrequent entity that can be a diagnosis and surgical challenge]. / Conexión anómala de la vena cava inferior a la aurícula izquierda: entidad poco frecuente que puede plantear un reto diagnóstico y quirúrgico.

This is the diagnostic experiences as well as the surgical mode of treatment used in a 31 years old women suffering diversion of the inferior vena cava into the left atrium associated with atrial septal defect. The patient had been previously studied and operated thrice under conventional circumstances at different institutions in order to solve the septal defect. The hemodynamic solution had not been reached due to a missing pathological definition. The cineangiogram through the saphenous vein specified the left atrium form the inferior vena cava. Some considerations are made on the surgical methods used for the fourth operation, and in regard of the fact that the patient refused blood transfusion because of religious convictions (Jehova Witness).

Flow injection spectrophotometric determination of lactic acid in skimmed milk based on a photochemical reaction.

A spectrophotometric method for the determination of lactic acid in milk samples based on the use of a photochemical reaction carried out in a Flow Injection System is proposed. Determination is based on the reaction between lactic acid and Fe(III), which is reduced to Fe(II) in the presence of UV light, being the latter made to react with o-phenanthroline. The complex formed between Fe(II) and o-phenanthroline, Fe(o-phen)(3)(2+) (ferroin) is a coloured compound and it can be spectrophotometrically monitored at 512 nm. The method shows a linear range between 0.5 and 50 mug ml(-1) with a limit of detection of 0.16 mug ml(-1). The precision was +/-2.15 expressed as relative standard deviation (n=11) and the sample throughput of 30 samples h(-1). Also non-linear adjustments have been made and validated by ANOVA. The proposed method has been applied to the determination of lactic acid in both synthetic and milk samples.

[Struma cordis: first case in Mexico]. / Struma cordis: primer caso en México.

The Intracardiac ectopic thyroid is an extremely rare condition and there is no previous report on this subject in Mexico. This is the case of a 33 years old woman, with normal thyroid function. She was found to have an intracardiac tumor in the interventricular septum. The intraoperative biopsy showed typical thyroid follicules; tumor removal left a septal defect that was closed with a dacron patch suture. Two years follow-up showed normal echocardiographic images, good clinical status an normal thyroid functioning. A brief review of the literature is included.

[Simplified method of obtaining the correction factor for calculating ventricular volumes]. / Obtención simplificada del factor de corrección para el cálculo de los volúmenes ventriculares.

For the accurate measurement of ventricular volume it is required the obtainment of a correction factor for the magnification caused by the non-parallel X-rays and the "pincushion" distortion, which causes more magnification in the periphery than in the center of the fluoroscopic field. The Kasser and Kennedy method is based in the attainment of the relation between the actual and projected dimensions of a micrometrically calibrated grid filmed at the distance measured between the intensifier tube and the mid-thoracic line during the ventriculography. This technique is very accurate but expensive and troublesome. With the simpler catheter method it is obtained the relation between the projected and actual linear dimensions of the ventriculographic catheter inmediately before ventriculography. This study was aimed to compare the accuracy of the catheter method and two other proposed methods, in which the relation between the projected and actual dimensions were obtained by filming one central coin or five arranged through the fluoroscopic field at the distance measured between the tube and the patients during the ventriculography. These four correction factors were obtained in 15 patients undergoing a diagnostic cardiac catheterization. The catheter method showed a poor correlation with the grid method (r = 0.34), while both coin methods showed a high correlation with the grid method (r = 0.93 and 0.92, respectively). It is concluded that the catheter method is inaccurate and therefore is unwise to use it for the estimation of ventricular volumes. Because the peripheric distortion is clinically unimportant, the central coin methods is proposed as a simplified method for obtaining the magnification correction factor.(ABSTRACT TRUNCATED AT 250 WORDS)

Cambios en la reserva coronaria con el uso de dipiridamol oral y su correlacion angiografica. / Changes in coronary reserve with the use of oral dipyridamole and its angiographic correlation

Por metodo doble ciego se estudiaron 40 pacientes con insuficiencia coronaria, administrando a la mitad de ellos 75 mg de dipiridamol tres veces al dia y a la otra mitad placebo durante tres meses consecutivos. Los pacientes que recibieron dipiridamol mostraron un aumento en la tolerancia a la prueba de esfuerzo en la banda sinfin, asi como una recuperacion electrocardiografica mas rapida al suspender esta prueba. Durante un segundo periodo de tres meses se administro en estudio abierto, a treinta de estos cuarenta pacientes, 75 mg de dipiridamol tres veces al dia.Los pacientes que inicialmente habian recibido placebo, mostraron un notable incremento en la tolerancia a la prueba de esfuerzo y en el tiempo de recuperacion electrocardiografica. Los pacientes que recibieron dipiridamol, durante los dos periodos de estudio, tambien mejoraron en los parametros estudiados, pero en menor intensidad en este segundo periodo de tratamiento. El estudio angiografico coronario practicado en catorce pacientes revela que el dipiridamol ejerce un efecto terapeutico mas intenso en aquellos en que la funcion contractil ventricular esta mas comprometida

[The diastolic function of the left ventricle. I. The ventricular suction]. / La función diastólica del ventrículo izquierdo. I. El llenado ventricular.

The paper describes the normal and pathological characteristics of left ventricular filling. There are described some of the most sophisticated methods of assessing left ventricular function: The volume-time curve, the rate of change of left ventricular volume (dV/dt) and the pressure-volume loop. It is discussed the phenomenon of ventricular diastolic suction as an accessory mechanism of filling in some restrictive disorders.

[Lupus profundus]. / Lupus profundo.

Seven cases of lupus erythematosus profundus are described (chronic discoid lupus erythematosus with athrophic panniculitis) with dissemination of one of them. All patients were females. The authors stress their opinion that it should not be called as lupus profundus, the cases of lupus erythematosus disseminated with erythema nodosum neither the cases of L.E.S. preceded or associated with the so called Weber-Christian's type of panniculitis. Six of the cases had athrophic alopecia of scalp by lupus discoid.

[Contralateral comparison between diflucortolone valeriante and flumethasone pivalate in ointments. Double-blind study]. / Comparación contralateral entre el valerianato de diflucortolona y el pivalato de flumetasona en pomada. Estudio doble ciego

Double blind study with contralateral comparison, between diflucortolon valerianat, 0.1% and the flumetason pivalat, 0.02% in pomades (ointments). Selection of 52 patients both sexes and variable ages with bilateral dermatological inflamatory lesions and with simetric preference: Psoriasis, "eczema vario" and neurodermatitis. In psoriasis, diflucortolon offered better results: the same occurred in the cases of eczema, and in neurodermatitis. The efficacy was similar. There were no appearances of negative secondary effects because of the used doses and time.