Measurement of radium and thorium isotopes in environmental samples by alpha-spectrometry

The final publication is available at Springer via http://dx.doi.org/10.1007/BF02035979[EN] A new method for the determination of low-level radium and thorium isotopes in environmental samples by α-spectrometry is described. Thorium and radium isotopes were chemically separated from the same sample, by using the same tracer (229Th). Two different ways were explored for the concentration process in water samples, obtaining a chemical yield for Ra isotopes between 70–90% in both cases using KMnO4 as carrier and BaCl2 and FeCl3, respectively. The method can also be directly applied for uranium measurements, but in this case there is a limitation on the range of uranium isotopes that can be analyzed.One of us (M.J.R.A.) is grateful to Institución Valenciana de Estudios e Investigación, Spain (IVEI) for fellowshipRodríguez Álvarez, MJ.; Sánchez, F. (1995). Measurement of radium and thorium isotopes in environmental samples by alpha-spectrometry. Journal of Radioanalytical and Nuclear Chemistry. 191(1):3-13. doi:10.1007/BF02035979S3131911W.H.O. Method of Radiochemical Analysis, Univ. of Tokio, Intern. edition, 23 (1967) 117.T. OKUBO, M. SAKANOUE, Geochem. J., 9 (1975) 221.TJOE-PA LIM, N. K. DAVE, N. R. CLOUTIER, Appl. Radiat. Isot., 40 (1989) 63.G. J. HANCOCK, P. MARTIN, Appl. Radiat. Isot., 42 (1991) 63.M. KOIDE, K. W. BRULAND, Anal. Chim. Acta, 75 (1975) 1.K. J. ODELL, Proc. 4th Symp. on the Determination of Radionuclides in Environmental and Biological Materials, April 1983, Ed-Rd Press, London.L. HALLSTADIUS, Nucl. Instrum. Methods Phys. Res., 223 (1984) 266.Radionuclide Transformations, Annals of the ICRP, ICRP Publication 38, Pergamon Press, Vol. 11, 1983, p. 13.M. J. RODRÍGUEZ-ALVAREZ, F. SÁNCHEZ, E. NAVARRO, Proc. 3rd Inter. Summer School, Huelva Spain, M. GARCÍA-LEÓN and G. MADURGA (Eds), World Scientific, Singapore, 1994.M. J. RODRÍGUEZ-ALVAREZ, F. SÁNCHEZ, J. Radioanal. Nucl. Chem., 190 (1995) 123.C. W. SILL, Anal. Chem., 49 (1977) 618.J. L. GASCÓN MURILLO, PhD Thesis, University of Zaragoza, Spain, 1990.M. C. MORÓN, A. MARTINEZ-AGUIRRE, M. GARCÍA-LEÓN, Intern. Conf. on Environmental Radioactivity in the Mediterranean Area, Barcelona, 10–13 May 1988. SNE-ENS, Barcelona, 1988, p. 111.M. YAMAMOTO, K. KOMURA, K. UENO, Radiochim. Acta, 46 (1989) 137.R. GARCÍA-TENORIO, M. GARCÍA-LEÓN, G. MADURGA, C. PIAZZA, Anal. Física B, 82 (1986) 238

Clinical characteristics and outcome of drug-induced liver injury in the older patients: from the young-old to the oldest-old

Older patients with hepatotoxicity have been scarcely studied in idiosyncratic drug-induced liver injury (DILI) cohorts. We sought the distinctive characteristics of DILI in older patients across age groups. A total of 882 DILI patients included in the Spanish DILI Registry (33% ≥ 65 years) were categorized according to age: “young” (< 65 years); “young-old” (65–74 years); “middle-old” (75–84 years); and “oldest-old” (≥ 85 years). All elderly groups had an increasingly higher comorbidity burden (P < 0.001) and polypharmacy (P < 0.001). There was a relationship between jaundice and hospitalization (P < 0.001), and both were more prevalent in the older age groups, especially in the oldest-old (88% and 69%, respectively), and the DILI episode was more severe (P = 0.029). The proportion of females decreased across age groups from the young to the middle-old, yet in the oldest-old there was a distinct female predominance. Pattern of liver injury shifted towards cholestatic with increasing age among top culprit drugs amoxicillin-clavulanate, atorvastatin, levofloxacin, ibuprofen, and ticlopidine. The best cutoff point for increased odds of cholestatic DILI was 65 years. Older patients had increased non–liver-related mortality (P = 0.030) as shown by the predictive capacity of the Model for End-Stage Liver Disease score (odds ratio (OR) = 1.116; P < 0.001), and comorbidity burden (OR = 4.188; P = 0.001) in the 6-month mortality. Older patients with DILI exhibited an increasingly predominant cholestatic phenotype across a range of culprit drugs, other than amoxicillin-clavulanate, with increased non–liver-related mortality and require a different approach to predict outcome. The oldest DILI patients exhibited a particular phenotype with more severe DILI episodes and need to be considered when stratifying older DILI populations

Effect of cooling rate during solidification on the hard phases of M23C6-type of cast CoCrMo alloy

Microstructural morphology of CoCrMo alloy by control of the cooling rate during the solidification was investigated. Samples were obtained using both an induction furnace for slow cooling rate and electric arc furnace for fast cooling rate. Microstructural characterizations were performed with metallographic techniques. It was found that the difference between the formation temperature of hard secondary phases of M23C6-type carbides determine the reduction of carbide size by increasing the cooling rate

Effect of cooling rate during solidification on the hard phases of M23C6-type of cast CoCrMo alloy

Microstructural morphology of CoCrMo alloy by control of the cooling rate during the solidification was investigated. Samples were obtained using both an induction furnace for slow cooling rate and electric arc furnace for fast cooling rate. Microstructural characterizations were performed with metallographic techniques. It was found that the difference between the formation temperature of hard secondary phases of M23C6-type carbides determine the reduction of carbide size by increasing the cooling rate

Pulsational frequencies of the eclipsing delta-Scuti star HD 172189

The eclipsing delta-Scuti star HD 172189 is a probable member of the open cluster IC 4756 and a promising candidate target for the CoRoT mission. The detection of pulsation modes is the first step in the asteroseismological study of the star. Further, the calculation of the orbital parameters of the binary system allows us to make a dynamical determination of the mass of the star, which works as an important constraint to test and calibrate the asteroseismological models. From a detailed frequency analysis of 210 hours of photometric data of HD 172189 obtained from the STEPHI XIII campaign we have identified six pulsation frequencies with a confidence level of 99% and a seventh with a 65% confidence level in the range between 100-300 uHz. In addiction, three eclipses were observed during the campaign, allowing us to improve the determination of the orbital period of the system.Comment: 6 pages, 7 figure

Mechanism of the negative inotropic effect of naringin in mouse heart [Mecanismo del efecto inotrópico negativo de la naringina en el corazón de ratón]

Abstract Resumen Context: Naringin (NRG) is the major flavonoid (flavanone glycoside) in grapefruit juice. Its biological activity has been only partially characterized and little is known about the mechanism of the negative inotropic action of this flavonoid. Aims: To evaluate the effects of NRG on the surface electrogram (ECG) and the force of contraction (FC) of mice hearts as well as on the sodium (INa), calcium (ICaL) and Na + -Ca 2+ exchange (INaCaX) currents of enzymatically isolated mouse ventricular cardiomyocytes. Methods: ECG and FC were recorded on mouse hearts perfused in a Langendorff column. Ventricular cardiomyocytes were enzimatically dissociated and ionic currents recorded with the patch-clamp technique. Results: NRG increased RR interval and shortened corrected QT only at high concentrations (30-100 µM). However, at a fixed heart rate, it decreased FC with an IC50 of 0.4 µM. NRG reduced INa with an IC50 of 0.07 µM but with a maximal inhibition of 60 %. NRG also depressed ICaL with an IC50 of 0.013 µM and increased its fast inactivation time constant. The effects on ICaL were not voltage-dependent. INaCaX was not affected by NRG. Conclusions: Our results indicate that NRG exerts a negative inotropic effect in mice hearts that could be explained by a decrease in INa and ICaL. These actions should be taken into account when considering this molecule either as a dietetic supplement or as a template to develop therapeutic agents for human diseases. Contexto: La naringina (NRG) es el principal flavonoide (glicósido de flavanona) en el jugo de toronja. Su actividad biológica ha sido solo parcialmente caracterizada y poco se conoce acerca del mecanismo de la acción inotrópica negativa de este flavonoide. Objetivos: Evaluar los efectos de la NRG sobre el electrograma de superficie (ECG) y la fuerza de contracción (FC) de corazones de ratón, así como sobre las corrientes de sodio (INa), calcio (ICaL) y del intercambiador Na + -Ca 2+ (INaCaX) en cardiomiocitos ventriculares de ratón, aislados enzimáticamente. Métodos: El ECG y la FC se registraron en corazones de ratón perfundidos en una columna de Langendorff. Los cardiomiocitos ventriculares se disociaron enzimáticamente y las corrientes iónicas se registraron con la técnica de patch-clamp. Resultados: La NRG incrementó el intervalo RR intervalo y acortó el QT solo a altas concentraciones (30-100 µM). No obstante, a frecuencia cardíaca fija, disminuyó la FC con un IC50 de 0.4 µM. La NRG redujo INa con un IC50 de 0.07 µM pero con una máxima inhibición de 60 %. La NRG también redujo ICaL con un IC50 de 0.013 µM e incrementó su constante de inactivación rápida. Los efectos sobre ICaL no fueron dependientes del potencial. La INaCaX no fue afectada por la NRG. Conclusiones: Nuestros resultados indican que la NRG ejerce un efecto inotrópico negativo en corazones de ratón que puede ser explicado por una reducción en INa e ICaL. Esas acciones deben ser tomadas en cuenta al considerar a esta molécula como suplemento dietético o como plantilla para desarrollar nuevos agentes terapéuticos para tratar las enfermedades en humanos

Integrating pressure sensor control into semi-solid extrusion 3D printing to optimize medicine manufacturing

Semi-solid extrusion (SSE) is a three-dimensional printing (3DP) process that involves the extrusion of a gel or paste-like material via a syringe-based printhead to create the desired object. In pharmaceuticals, SSE 3DP has already been used to manufacture formulations for human clinical studies. To further support its clinical adoption, the use of a pressure sensor may provide information on the printability of the feedstock material in situ and under the exact printing conditions for quality control purposes. This study aimed to integrate a pressure sensor in an SSE pharmaceutical 3D printer for both material characterization and as a process analytical technology (PAT) to monitor the printing process. In this study, three materials of different consistency were tested (soft vaseline, gel-like mass and paste-like mass) under 12 different conditions, by changing flow rate, temperature, or nozzle diameter. The use of a pressure sensor allowed, for the first time, the characterization of rheological properties of the inks, which exhibited temperature-dependent, plastic and viscoelastic behaviours. Controlling critical material attributes and 3D printing process parameters may allow a quality by design (QbD) approach to facilitate a high-fidelity 3D printing process critical for the future of personalized medicine