DESIGN AND STUDY OF DIMENSIONAL PARAMETERS INFLUENCE ON VORTEX TUBE BEHAVIOR

Vortex tube is a thermodynamic device, with no moving parts, applied to separate hot and cold air from compressed air injected into the tube. It has many applications in the industry, for example, among others, it can be mentioned electronic systems cooling, machining processes cooling and environmental chambers. This paper presents the design and tube dimensioning based on parameters and data found in the literature. Therefore, a prototype has been made and tested, which allowed the understanding of the influence of internal tube diameter and width on the hot and cold air temperatures while submitted to compressed air with pressure varying from 1 to 2.5bar. Results of tested configurations indicates that the relation between tube length and diameter (L/D) has small influence on vertex tube behavior, meanwhile, 3/8” tube diameter shows lowest temperatures on cold flow (-6.5°C, -8.0°C and -8.5°C) and higher COP (≈ 0.15)

The complex biology of FOXO

FOXO transcription factors control proliferation, apoptosis, differentiation and metabolic processes. Loss of FOXO function has been identified in several human cancers, and results in increased cellular survival and a predisposition to neoplasia, especially in epithelial cancer. FOXO factors are therefore bona fide tumor suppressors, and their potential use as therapeutic targets in cancer has been a matter of debate. Importantly, FOXO factors can also positively regulate cell survival through the activation of several detoxification genes, complicating its putative therapeutic potential. Targeting of FOXO factors has also been proposed for the treatment of metabolic dysfunctions such as diabetes mellitus, immunological disorders and neurodegeneration, as well as for the prevention of aging by maintaining the hematopoyetic stem cells niche. But again, data has accumulated that cautions against the potential use of the FOXO activators in these settings. Therefore, greater understanding of the regulation of FOXO target specificity is still needed to boost its use as a therapeutic target. The four members of the FOXO family (FOXO1, FOXO3A, FOXO4 and FOXO6) have distinct but overlapping cellular functions, although they seem to bind a common set of DNA sites. This fact together with the observation that FOXOs are only partially dependent on their DNA binding activity to regulate their target genes highlights the fact that the interaction of the FOXOs with other transcription factors is crucial for the FOXO-mediated transcriptional programs. In this review, we provide an overview of recent progress in the understanding of the modulation of FOXO activity and target specificity by transcription factors and coactivators.Ministerio de Ciencia e InnovaciónMinisterio de Sanidad y ConsumoFundación Pro CNICDepto. de Biología CelularFac. de Ciencias BiológicasTRUEpu

Methodological Approach for the Evaluation of FOXO as a Positive Regulator of Antioxidant Genes

All four FOXO isoforms have been shown to respond to changes in the cellular redox status of the cell, and regulate the expression of target genes that in turn can modulate the cellular oxidative status. However, the mechanisms involved are still controversial. It is clear though that redox regulation of FOXO factors occurs at different levels. The proteins themselves are redox-sensitive and their capacity to bind their target sites seems to be at least partially dependent on their oxidative status. Importantly, several of the cofactors that are known to regulate FOXO transcriptional activity are also sensitive to changes in the cellular redox status, in particular the deacetylase SirT1 is activated in response to reduced levels of reducing equivalents (increased NAD+/NADH+ ratio) and the coactivator PGC-1α is induced in response to increased cellular oxidative stress. Furthermore, nuclear localization of FOXO factors is also regulated by proteins that, like AKT, are themselves regulated directly or indirectly by the cellular levels of reactive oxygen and nitrogen species. In this technical review, we aim to update the current status of our knowledge of how to handle redox-regulated FOXO factor research in order to better understand FOXO biology.Ministerio de Economía, Industria y Competitividad (España)European ComissionDepto. de Biología CelularFac. de Ciencias BiológicasTRUEpu

Schmalflächenbeschichtung mit dem Laser - alte Technologie in neuem Licht. Teil 2: Der Fügeprozess an der Kantenleimmaschine

(Fortsetzung aus Heft 47 (2006) 3, S. 37-42) An einer Kantenanleimmaschine (Typ Homag Optimat KL77) wurde ein kontinuierlich arbeitender, scannender Diodenlaser (Leistung 2,7 kW) so installiert, dass der Strahl zu einer Linie aufgeweitet wurde und die Fügezone erwärmte. Beschichtungsversuche an den Schmalflächen von Holzwerkstoffplatten mit verschiedenen Beschichtungsmaterialien (vorbeschichtete Dekorpapierbänder, Furniere, PVC-Bänder) und Klebstoffen (niedrigschmelzende Ethylenactat-Klebstoffe, Polyolefin- Klebstoff) bei Vorschubgeschwindigkeiten von 15 m/min bis 40 m/min und Laserleistungen von 1400 W bis 2200 W wurden durchgeführt. Die Klebfugen wurden mit einer Thermographie-Kamera betrachtet, wobei sich zeigte, dass die Erwärmung im Randbereich der Fuge größer und damit dort die Verklebung besser war. Die Verklebungen wurden außerdem nach der Festigkeit (Prüfung durch aufgebrachtes Moment) und der Wasseraufnahme (Gewichtszunahme während der Lagerung im Wasserbad) bewertet. Die Festigkeit war bei kleinster Vorschubgeschwindigkeit am größten. Die Wasseraufnahme war deutlich geringer als bei Verklebungen mit dem konventionellen Auftrag durch eine Walze. Eine Wirtschaftlichkeitsbetrachtung ergab nur geringfügig höhere Kosten gegenüber diesem Verfahren durch die Lasererwärmung. Dem stehen als Vorteile gegenüber, dass bei höherer Temperatur schmelzende Klebstoffe eingesetzt und Probleme mit Verschmutzungen vermieden werden können. Das lasergestützte Fügen kann daher sinnvoll eingesetzt werden