J. Martin Gil

CHARACTERIZATION OF FATTY ACID METHYL ESTERS BY THERMAL ANALYSIS

The thermal stability of selected straight-chain (C6-C14) esters of fatty acids has been studied by TG-DTG and DTA analysis. In DTG, a peak is detected between 84° and 125° C followed by a main effect in the range 105°–215°C, whereas in DTA only an exothermic peak appears in the range of 126.5° to 187°C (onset temperatures). The temperatures of these effects have been related with ignition points, molecular weights and boiling points.The characteristics of melting and recrystallization of the above fatty acid methyl esters and those with carbon numbers between C14 and C24 have been established by DSC along the melting range between −83° and 50°C. Polymorphism appears in caproic, heptanoic, palmitic and stearic acid methyl esters.ZusammenfassungMittels TG-DTG und DTA wurde die thermische Stabilität einiger ausgewählter geradkettiger (C6-C14) Fettsäureester untersucht. In der DTG-Kurve wird ein Peak zwischen 84° und 125°C beobachtet, gefolgt von einem großen Effekt im Bereich 105°–215°C, wobei in der DTA-Kurve im Bereich 126,5° bis 187° (onset-Temperaturen) nur ein einziger exothermer Peak erscheint. Die Temperaturen dieser Effekte wurden dem Zündungspunkt, den Molekülgewichten und den Siedepunkten zugeordnet.Mittels DSC wurden im Schmelzbereich zwischen −83° und 50°C die Schmelz- und Rekristallisationsmerkmale obiger Fettsäuremethylester und solcher mit einer Kohlenstoffatomanzahl zwischen C14 und C24 ermittelt. Polymorphie tritt in den Methylestern von Kapron, Heptyl, Palmitin-und Stearinsäure auf.

Aportación al estudio de la otosclerosis y del síndrome de Van der Hoeve

Resumen Hemos realizado un estudio ultraestructural y microanalitico de estribos procedentes de pacientes otosclerosos, sanos y afectos por el sindrome de Van der Hoeve a fin de determinar los cambios en la composicion mineral de los mismos. Para ello hemosutilizado metodos no destructivos –microscopia electronica de barrido asociado a espectroscopia por dispersion de energia de rayos X (EDAX)– y otros destructivos (espectrografia con infrarrojos mediante transformada de Fourier). Utilizando la relacion Ca/P hemos determinado que la composicion mineral de los estribos es distinta en individuos normales, otosclerosos y afectos por el sindrome de Van der Hoeve. En esta ultima entidad hemos detectado una composicion mineral inusual en huesos sanos: la brushita. Abstract Morphological and microchemical changes that effect to the otosclerotic stape in the Van der Hoeve’s syndrome were examined with a scanning electron microscope equipped with an energy dispersive X-ray fluorescence. Using the Ca/P ratio as criterion –measured by the characteristic x-ray fluorescence– it was shown that the Van der Hoeve stape had a higher Ca/P ratio (2.6:1) as compared to the normal stape (2:1). The Van der Hoeve’s syndrome lesions as poorly mineralized, with low calcium salt and apparent increase of phosphates. This finding indicates a possible change from hydroxyapatite (or apatite) to brushite, which imply an acidification of bone.

Thermal analysis of agricultural residues with application to production fuels

An important application of agricultural residues is as fuels for combustion processes. This paper shows how thermal analysis can be used for characterization of different kinds of cereals with a view to increasing efficiency in combustion processes. Results are in good agreement with those derived from standard ASTM methods.ZusammenfassungEine wichtige Anwendung von agrarwirts chaftlichen Restbeständen ist die Verwendung als Brennstoff für Verbrennung sprozesse. Es wird hier gezeigt, wie die Thermoanalyse zur Charakterisierung verschiedener Getreidearten angewendet werden kann, um eine höhere Effektivität der Verbrennungsprozesse zu erreichen. Die erhaltenen Resultate stehen in guter Übereinstimmung mit den mittels Standard-ASTM-Methoden ermittelten Ergebnissen.

On the Synthesis of Triiodides of Aluminium, Gallium and Indium

Abstract The direct union of the elements aluminum, gallium and indium with iodine in n-hexane is a convenient laboratory preparation of pure metal triiodides.

Estudio descriptivo del comienzo de la diabetes mellitus tipo 1 y sus familiares de primer grado

Background: Few information about descriptive studies of autoimmunity in diabetes mellitus type 1 onset patients and family exist. The aim of our study was to analyze clinical and biochemical parameters of onset diabetes mellitus type 1 patients and first degree families. Patients and methods: Forty seven onset diabetes mellitus type 1 patients and 148 first degree families were studied, between January 1999 and December 2002, in the west area of Valladolid. In all cases and families an anthropometric study and biochemical determination with autoimmunity levels were performed. Results: Average age in onset diabetes mellitus type 1 patients was 16.09 (9.36) years, without differences between males (32 cases, 68%) and females (15 cases, 32%), with an incidence of 4.66 cases/100,000 habs./year. Average values of peroxidase antibodies (antiPTO) and glutamic descarboxilase antibodies (antiGAD) were higher in diabetic patients than in families. No differences were detected in insulin antibodies (IAA) and tiroglobuline antibodies (antiTG). No correlation was detected between anti TPO and anti pancreas. Autoantibodies did not influence in glycemic control. Average dose of NPH insulin and regular insulin were 27.58 (13.88) UI/d y 3.05 (4.90) UI/d, respectively. Conclusions: Average age of onset diabetes mellitus type 1 patients was similar than other studies, with a high frequency of males. VAlues of antiGAD y antiTPO were higher in diabetic patients than families. No correlation between autoimmunity and glycemic control was detected.

Structure and Electron Density of Trans-Dichloro-Bis(Creatinine) Platinum(II) Di-Hydrate

Platinum compounds have biological interest owing to their anti-tumoral properties. A series of creatinine platinum compounds has been synthesized at Escuela Tecnica Superior de Ingenieros Industriales, and their structure determination is being undertaken at Departamento de Fisica, Coimbra.