ABSTRACT
Not required for Clinical Vignettes.
Subject(s)
Hypophosphatemia , Osteomalacia , Paraneoplastic Syndromes , Humans , Hypophosphatemia/chemically induced , Osteomalacia/etiology , Paraneoplastic Syndromes/etiology , Fibroblast Growth FactorsABSTRACT
The purpose of the present study was to determine the impact of image quality on the results of air void system parameters determination in air-entrained concretes. The focus was on technical aspects related to the preparation of the scanned image of the concrete surface, which was then subjected to 2D surface analysis. Image processing aimed at separating joined voids and removing various types of defects in aggregate and cement mortar. The specific surface of the voids was determined with the air void equivalent diameter or perimeter as the calculation basis. Applying the Schwartz-Saltykov method, the 3D distribution of the air voids was reconstructed based on 2D measurements. On this basis, the micro-air content A300 was determined. The results of the 2D method were compared with the results of determinations carried out using the linear traverse (1D) method according to EN 480-11. The tests confirm the need to correct the image prior to measurements. Comparative tests showed good agreement between the air void system parameters determined using the 2D analysis and the EN 480-11 chord length counting method.
ABSTRACT
The European concrete standard EN 206 introduces the k-value concept as one of the three methods allowing the use of granulated blast furnace slag in the design of the freeze-thaw-resistant concrete mix. It is assumed that the freeze-thaw durability of the concrete, whose composition (w/c ratio) has been corrected by adopting a certain k-value, is the same as the freeze-thaw resistance of the reference concrete made with the cement containing no addition (CEM I). This article presents the results of freeze-thaw resistance analysis (modified with the ASTM C666A standard Class XF3) of 24 series of concretes made with a binder containing varied amounts of slag, with a w/b ratio ranging from 0.25 to 0.55. The aim of the study was to estimate the k-value as a parameter defined by the w/b ratio and the slag content in the binder. In this approach, the k-value is determined by trial and error in such a way that the deformation of the concrete specimens containing the slag corresponds to the deformation of the reference concrete. As shown by the analysis, the k-value decreases with increasing slag content in the binder.
ABSTRACT
Circadian rhythm plays an important role in human physiology. Its abnormal functioning results, among others, in jet lag disorder (JLD- Jet Lag Disorder), which is a discomfort experienced by people travelling between time zones, as well as being the cause for metabolic diseases in people working shifts. Recent studies have shown the role of vasopressin V1a and V1b suprachiasmatic nucleus (SCN- surachiasmatic nucleus) of the hypothalamus in the regulation of circadian rhythms. Mice genetically lacking receptors are resistant to disturbances of circadian rhythm, and are characterized by an almost immediate adjustment to the new rhythm. A similar effect is achieved by pharmacologically blocking V1a and V1b receptors. Research gives hope of overcoming this disorder to travellers who traverse time zones at high speed, as well as creating the possibility of adaptation to shift work without provoking any negative consequences over one´s health.
