39 research outputs found
Thermistor formation using batio3 powders synthesised by the pechini method
Barium titanate (BaTiO3) is a compound of interest in the field of electroceramics which is widely used in the manufacture of capacitors, piezoelectric transducers and resistive devices having a positive temperature coefficient (PTCR) and in manu- facturing pyroelectric and optoelectronic devices. Most of these devices are obtained by consolidating high purity, suitable sized particle ceramic powders; structured synthesis methods are required to ensure such requirements. BaTiO3 powders were synthesised by a polymeric precursor method (Pechini) in this work. Very pure, small particle sized, raw material was obtained. These powders were characterised using thermo- gravimetric and differential thermal analysis (TGDT), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). The results indicated that samples treated at 650°C presented cubic BaTiO3 as unique crystalline phase. If a sample were treated at 1,100°C, the tetragonal phase having a c/aEl titanato de bario, BaTiO3, es un compuesto de gran interés en el ámbito de la electrocerámica, ya que se utiliza en la fabricación de condensadores, transductores piezoeléctricos y dispositivos resistivos con coeficiente positivo de temperatura (PTCR), así como en la manufactura de piroeléctricos y dispositivos optoelectrónicos, entre otros dispositivos. La mayoría de estos componentes son conformados con polvos cerámicos de elevada pureza y tamaño de partícula adecuado. Esto exige estructurar métodos de síntesis que garanticen es- tos requerimientos. En este trabajo se sintetizaron polvos cerámicos de BaTiO3 por el método de precursor polimérico (Pechini), obteniéndose una materia prima muy pura y con pequeño tamaño de partícula. Los polvos obtenidos se caracterizaron utilizando análisis térmico (ATD/TG), difracción de rayos X (DRX) y calorimetría diferencial de barrido (DSC). Los resultados indican que en las muestras tratadas a 650 °C la única fase cristalina presente es el BaTiO3 cúbico y a 1.100 °C la tetragonal, con una relación c/a and lt; 1.007. Las muestras tratadas a 1.100 °C presentaron una transición ferroeléctrica a paraeléctrica a una temperatura de T ≈ 123 °C. Los polvos cerámicos de BaTiO3 tetragonal fueron prensados uniaxialmente y posteriormente sinterizados a 1.200 °C durante 2 horas. Estas muestras se caracterizaron eléctricamente, obteniéndose curvas de resistencia eléctrica en función de la temperatura (R-T), evidenciándose en ellas su comportamiento termistor tipo PTCR. Además, se midió la variación de la corriente-voltaje (I-V) a diferentes temperaturas
Risk scores' performance and their impact on operative decision‑making in left‑sided endocarditis: a cohort study
Theaccuracy of contemporary risk scores in predicting perioperative mortality in infective endocarditis (IE) remains controversial. The aim is to evaluate the performance of existent mortality risk scores for cardiovascular surgery in IE and the impact on operability at high-risk thresholds. A single-center retrospective review of adult patients diagnosed with acute left-sided IE undergoing surgery from May 2014 to August 2019 (n = 142) was done. Individualized risk calculation was obtained according to the available mortality risk scores: EuroScore I and II, PALSUSE, Risk-E, Costa, De Feo-Cotrufo, AEPEI, STS-risk, STS-IE, APORTEI, and ICE-PCS scores. A cross-validation analysis was performed on the score with the best area under the curve (AUC). The 30-day survival was 96.5% (95%CI 91-98%). The score with worse area under the curve (AUC = 0.6) was the STS-IE score, while the higher was for the RISK-E score (AUC = 0.89). The AUC of the majority of risk scores suggested acceptable performance; however, statistically significant differences in expected versus observed mortalities were common. The cross-validation analysis showed that a large number of survivors (> 75%) would not have been operated if arbitrary high-risk threshold estimates had been used to deny surgery. The observed mortality in our cohort is significantly lower than is predicted by contemporary risk scores. Despite the reasonable numeric performance of the analyzed scores, their utility in judging the operability of a given patient remains questionable, as demonstrated in the cross-validation analysis. Future guidelines may advise that denial of surgery should only follow a highly experienced Endocarditis Team evaluation
Liver-specific ablation of insulin-degrading enzyme causes hepatic insulin resistance and glucose intolerance, without affecting insulin clearance in mice
The study was partially presented as a poster in the 53rd Annual Meeting of the European Association for the Study of Diabetes, Lisbon 2017.The role of insulin-degrading enzyme (IDE), a metalloprotease with high affinity for insulin, in insulin clearance remains poorly understood. OBJECTIVE: This study aimed to clarify whether IDE is a major mediator of insulin clearance, and to define its role in the etiology of hepatic insulin resistance.[Methods] We generated mice with liver-specific deletion of Ide (L-IDE-KO) and assessed insulin clearance and action.[Results] L-IDE-KO mice exhibited higher (~20%) fasting and non-fasting plasma glucose levels, glucose intolerance and insulin resistance. This phenotype was associated with ~30% lower plasma membrane insulin receptor levels in liver, as well as ~55% reduction in insulin-stimulated phosphorylation of the insulin receptor, and its downstream signaling molecules, AKT1 and AKT2 (reduced by ~40%). In addition, FoxO1 was aberrantly distributed in cellular nuclei, in parallel with up-regulation of the gluconeogenic genes Pck1 and G6pc. Surprisingly, L-IDE-KO mice showed similar plasma insulin levels and hepatic insulin clearance as control mice, despite reduced phosphorylation of the carcinoembryonic antigen-related cell adhesion molecule 1, which upon its insulin-stimulated phosphorylation, promotes receptor-mediated insulin uptake to be degraded.[Conclusion] IDE is not a rate-limiting regulator of plasma insulin levels in vivo.This work was supported by grants from the Ministerio de Economía, Industria y Competitividad: SAF2014-58702-C2-1-R and SAF2016-77871-C2-1-R to ICC; SAF2014-58702-C2-2-R and SAF2016-77871-C2-2-R to GP; supported by the EFSD European Research Programme on New Targets for Type 2 Diabetes supported by an educational research grant from MSD to ICC and GP; the National Institutes of Health: R01-DK054254, R01-DK083850 and RO1-HL-112248 to SMN, and R01-GM115617 to MAL; and the American Diabetes Association: Career Development Award 7-11-CD-13 to MAL.Peer reviewe
Tissue specific expression of human fatty acid oxidation enzyme genes in late pregnancy
Background: Abnormal fatty acid oxidation (FAO) is associated with maternal and fetal complications during
pregnancy. The contribution of maternal and fetal tissues to FAO capacity during late pregnancy is important to
understand the pathophysiology of pregnancy-associated complications. The aim of this study was to determine
the expression levels of mitochondrial FAO enzymes in maternal and fetal tissues during late normal pregnancy.
Methods: We have measured by Real-time PCR the levels of long- and medium -chain acyl-CoA dehydrogenase
(LCHAD and MCAD), two acyl-CoA dehydrogenases that catalyze the initial step in the mitochondrial FAO spiral.
Results: LCHAD and MCAD were expressed in maternal skeletal muscle, subcutaneous adipose tissue, placenta, and
maternal and fetal blood cells. LCHAD gene expression was four- to 16-fold higher than MCAD gene expression in
placenta, adipose tissue and skeletal muscle. In contrast, MCAD gene expression was ~5-fold higher in fetal blood
than maternal blood (p = 0.02), whereas LCHAD gene expression was similar between fetal blood and maternal
blood (p =0.91).
Conclusions: LCHAD and MCAD are differentially expressed in maternal and fetal tissues during normal late
pregnancy, which may represent a metabolic adaptation in response to physiological maternal dyslipidemia during
late pregnancy.Consejeria de Salud, Junta de Andalucía Num Expte: 0269/05
Formal Method for Mission Controller Generation of a Mobile Robot
International audienceThis article presents a methodology for generating a real-time mission controller of a submarine robot. The initial description of the mission considers the granularity constraints associated with the actors defining the mission. This methodology incorporates a formal analysis of the different possibilities for success of the mission from the models of each component involved in the description of the mission. This article ends illustrating this methodology with the generation of a real robotic mission for marine biodiversity assessment
Expression of insulin receptor (IR) A and B isoforms, IGF-IR, and IR/IGF-IR hybrid receptors in vascular smooth muscle cells and their role in cell migration in atherosclerosis
International audienceAbstractBackgroundAbnormal proliferation and migration of vascular smooth muscle cells (VSMCs) is a major contributor to the development of atherosclerotic process. In a previous work, we demonstrated that the insulin receptor isoform A (IRA) and its association with the insulin-like growth factor-I receptor (IGF-IR) confer a proliferative advantage to VSMCs. However, the role of IR and IGF-IR in VSMC migration remains poorly understood.MethodsWound healing assays were performed in VSMCs bearing IR (IRLoxP+/+ VSMCs), or not (IR−/− VSMCs), expressing IRA (IRA VSMCs) or expressing IRB (IRB VSMCs). To study the role of IR isoforms and IGF-IR in experimental atherosclerosis, we used ApoE−/− mice at 8, 12, 18 and 24 weeks of age. Finally, we analyzed the mRNA expression of total IR, IRB isoform, IGF-IR and IGFs by qRT-PCR in the medial layer of human aortas.ResultsIGF-I strongly induced migration of the four cell lines through IGF-IR. In contrast, insulin and IGF-II only caused a significant increase of IRA VSMC migration which might be favored by the formation of IRA/IGF-IR receptors. Additionally, a specific IGF-IR inhibitor, picropodophyllin, completely abolished insulin- and IGF-II-induced migration in IRB, but not in IRA VSMCs. A significant increase of IRA and IGF-IR, and VSMC migration were observed in fibrous plaques from 24-week-old ApoE−/− mice. Finally, we observed a marked increase of IGF-IR, IGF-I and IGF-II in media from fatty streaks as compared with both healthy aortas and fibrolipidic lesions, favoring the ability of medial VSMCs to migrate into the intima.ConclusionsOur data suggest that overexpression of IGF-IR or IRA isoform, as homodimers or as part of IRA/IGF-IR hybrid receptors, confers a stronger migratory capability to VSMCs as might occur in early stages of atherosclerotic process
Alterations of the cerebrospinal fluid proteins and subcommissural organ secretion in the arterial hypertension and ventricular dilatation. A study in SHR rats
The aim of this work was to analyze the
proteins in the cerebrospinal fluid (CSF) of
spontaneously hypertensive rats, to study their possible
role in the relationship between hydrocephalus, arterial
hypertension and alterations in the subcommissural
organ. Brains from control Wistar-Kyoto rats (WKY)
and spontaneously hypertensive rats (SHR) sacrificed
with chloral hydrate were used. Antiserums against some
cerebrospinal fluid protein bands and Reissner’s fiber
(RF) were used for immunohistochemical study of the
SCO. Ventricular dilation was observed in the lateral and
third ventricle of the SHR. Third ventricle ependyma
showed immunoreactive material (IRM) for antibody
against 141kDa protein band anti-B1 and 117 protein
band anti-B2 and the SCO of the SHR showed a
decrease of the IRM when compared with WKY rats. An
alteration in the expression of anti-RF was found to
compare the SCO of the WKY and SHR groups. Our
results demonstrate that hydrocephalus and hypertension
are interconnected in this kind of rat which produce
alterations in SCO secretions and some proteins of the
CSF
Expression of certain proteins in the subfornical organ and cerebrospinal fluid of spontaneously hypertensive rats
The objective of this study was to analyze
the proteins in the cerebrospinal fluid of spontaneously
hypertensive rats and to study their possible role in the
relationship between hydrocephalus, arterial
hypertension and variations in the subfornical organ.
Brains and cerebrospinal fluid from control Wistar-
Kyoto rats and spontaneously hypertensive rats
sacrificed with chloral hydrate were used. Cerebrospinal
fluid and extract of subfornical organ were processed by
protein electrophoresis. Antisera against protein bands of
141, 117 and 48 kDa and Concanavalin A were used for
immunohistochemical and western blot study of the
subfornical organ, adjacent circumventricular structures
and cerebrospinal fluid. Ventricular dilation in the
spontaneously hypertensive rats and the presence of
quite a lot of protein bands in the cerebrospinal fluid of
the hypertensive rats, which were either not observed or
scarcely present in the cerebrospinal fluid of the Wistar-
Kyoto rats, were confirmed. The subfornical organ, third
ventricle ependyma and choroideus plexus showed
immunoreactive material for antibodies against 141kDa,
117 and 48 kDa proteins band (anti-B1, anti-B2 and anti-
B3). The larger amount of the immunoreactive material
was found in the subfornical organ of the spontaneously
hypertensive rat. Our results and the alterations observed
by other authors in the subfornical organ in
hydrocephalic and hypertensive rats support the
possibility that this circumventricular organ, some
proteins of the cerebrospinal fluid and ventricular
dilation could be connected with the physiopathology of
this type of hypertension