The article discusses the display of computer generated holograms of 3D objects using a binary amplitude spatial light modulator. More precisely, it deals with binarization of a diffractive structure using dithering noise. It concludes that the dithering method is suitable for simple diffractive structures such as diffractive gratings, but fails to provide a good binarization of computer generated holograms of 3D objects., Článek se zabývá zobrazením počítačem generovaného hologramu 3D objektu na binárním amplitudovém prostorovém modulátoru světla, respektive binarizací difraktivních struktur. Rozvíjí myšlenku binarizace difraktivní struktury pomocí techniky ditheringu. Dospívá k závěru, že technika je vhodná pro jednoduché struktury typu difrakční mřížky, ale není vhodná pro počítačem generované hologramy 3D objektu., and Pokračování článku v příštím čísle
The influence of monopolar binaural galvanic stimulation of the vestibular system was studied on body sway. Subjects, with eyes closed, were standing on a hard support or on foam rubber. Their body sway was registered on a force platform at intervals of 50 s. Both polarities of direct current with intensity 1 mA were used as a galvanic stimulus during the whole recording interval. Changes of body sway amplitude and velocity were analyzed in situations with and without galvanic stimulation on two different support surfaces. In stance on the hard support, the cathodal polarization of labyrinths (in most subjects) reduced body sway velocity and decreased body sway slightly in the anteroposterior direction. Anodal polarization of labyrinths during 50 s did not affect the body sway parameters. The results on the foam rubber platform exhibited a significant reduction of body sway velocity induced by both anodal and cathodal polarization of the labyrinths. The decrease of body sway in the anteroposterior direction was also observed during cathodal polarization. The stabilizing effect of vestibular binaural monopolar stimulation on the upright stance was mainly observed in the postural control situation where the leg proprioceptive input was changed (stance on soft surface) and the role of vestibular input was more important.
Phenylcyclohexylglycoloylester of hydroxyethyldimethylhydrazonium (compound VGFB-3113) has been shown earlier to have a strong antimuscarinic effect on smooth muscle. Its affinity to muscarinic binding sites in homogenates of rat heart ventricles (M2 subtype), submandibular salivary gland (M3 subtype) and brain cortex (predominantly Ml subtype) has now been investigated in radioligand displacement experiments using (3H)quinuclidinyl benzilate ((3H)QNB) as a relatively non-specific muscarinic ligand. VGFB-3113 inhibited the binding of (3H)QNB with pKj values of 8.17, 8.73, and 8.52 in the heart, salivary gland, and brain cortex, respectively. It is concluded that the compound has a high affinity for muscarinic binding sites without strong preference for any of the Ml-M3 subtypes.
A hydroponic experiment was conducted to investigate bioaccumulation and photosynthetic activity response to Cd in sweet sorghum seedlings. The seedlings were treated with 0, 50, and 100 μM Cd for 15 d. Our results showed that morphological characteristics of sweet sorghum were significantly affected by Cd treatments. The Cd concentrations in roots and shoots increased with increasing Cd concentrations in the nutrition solution; higher Cd accumulation was observed in the roots. Meanwhile, the photosynthetic activity decreased significantly and a shape of chlorophyll (Chl) a fluorescence transient in leaves was altered by Cd treatments. The Chl contents in the leaves decreased significantly, which was demonstrated by a change of spectral reflectance. Our data indicated that the higher Cd concentration reduced Chl contents and inhibited electron transport in the leaves, leading to the decrease of photosynthetic activity., Z. C. Xue, J. H. Li, D. S. Li, S. Z. Li, C. D. Jiang, L. A. Liu, S. Y. Wang, W. J. Kang., and Obsahuje bibliografii
ECM is composed of different collagenous and non-collagenous proteins. Collagen nanofibers play a dominant role in maintaining the biological and structural integrity of various tissues and organs, including bone, skin, tendon, blood vessels, and cartilage. Artificial collagen nanofibers are increasingly significant in numerous tissue engineering applications and seem to be ideal scaffolds for cell growth and proliferation. The modern tissue engineering task is to develop three-dimensional scaffolds of appropriate biological and biomechanical properties, at the same time mimicking the natural extracellular matrix and promoting tissue regeneration. Furthermore, it should be biodegradable, bioresorbable and non-inflammatory, should provide sufficient nutrient supply and have appropriate viscoelasticity and strength. Attributed to collagen features mentioned above, collagen fibers represent an obvious appropriate material for tissue engineering scaffolds. The aim of this minireview is, besides encapsulation of the basic biochemical and biophysical properties of collagen, to summarize the most promising modern methods and technologies for production of collagen nanofibers and scaffolds for artificial tissue development., L. Koláčná, J. Bakešová, F. Varga, E. Košťáková, L. Plánka, A. Nečas, D. Lukáš, E. Amler, V. Pelouch., and Obsahuje bibliografii
This work evaluates the myocardial protective potential of potassium cardioplegia on ischaemically arrested and reperfused hearts by two cardioplegic solutions: the University of Wisconsin solution (UW) and the standard crystalloid solution of St. Thomas’ Hospital (ST). Evaluation of myocardial preservation was based on creatine kinase and lactate releases and on high-energy phosphate preservation of isolated rabbit hearts after 4 hours’ hypothermic ischaemia. A morphometric ultrastructural evaluation of mitochondria in cardiomyocytes was also performed. The hearts of 24 rabbits were normothermally perfused with oxygenated Krebs-Henseleit solution for 30 min (Langendorff preparation), and the baseline contractile performance and biochemical parameters were evaluated. The hearts were then arrested and stored in the cardioplegic solutions (12 UW and 12 ST) at 4 °C for 4 hours. The hearts were then rewarmed and reperfused with oxygenated Krebs-Henseleit solution for further 30 min. At the end of reperfusion, creatine phosphate and high energy phosphates were higher with UW (p<0.05); creatine kinase release during reperfusion was significantly lower with UW both at 15 min (p<0.01) and at 30 min (p<0.05). Lactate release during the first 15 min of reperfusion was about doubled (p<0.05) with respect to controls in both groups; at 30 min this increase had almost vanished ( + 8 %) with UW but not with ST ( + 30 %). Ultrastructural morphometry did not show any significant difference at the level of mitochondria between the two treatments. The results indicate, for UW, an improved myocardial preservation associated with relative retention of high-energy phosphates and higher recovery of mechanical function, accelerated metabolic recovery and reduced stress of cell membranes.