Mazzilli Oscillator as a tool in education Matic, Luka; Stojanovic, Sasa; Simovic, Vladimir
2020 43rd International Convention on Information, Communication and Electronic Technology (MIPRO),
2020-Sept.-28
Conference Proceeding
In an effort to visually show students the effects of Eddy currents (also called Foucault's currents), we have researched the possibility of using a Zero Voltage Switching circuit for the generation ...of such currents in a large, light and thin piece of metal. The Mazzilli oscillator provided with a much needed opportunity for such research and an interesting task for application of knowledge and skills acquired during studies.
This paper analyses a time series of chlorophyll-a profiles in the Adriatic from 1997 to 2019, and compares the data with satellite products with the view of analysing and reducing uncertainties in ...the corresponding satellite products. Three sources of uncertainties in satellite chlorophyll-a concentration are examined: (a) the algorithm itself; (b) the vertical structure of the water column; and (c) the phytoplankton community structure. Global and regional algorithms were examined, along with a local algorithm tuned using the time series data. The global algorithm produced the largest uncertainties when compared with the in situ data, followed by the regional and local algorithms. Correlation coefficient for the local algorithm was 0.690 - a significant increase from regional’s 0.420 and global’s 0.042. Both the global and the regional algorithms exhibited systemic errors that inversely were related to chlorophyll-a concentration, while the local algorithm displayed some reduction in the systematic errors, highlighting the value of local in situ observations, for improving sub-regional and local algorithms for retrieval of chlorophyll-a concentration from satellite ocean colour data. While the mixed layer has not shown any direct correlation with the uncertainties, it may facilitate exceptionally strong vertical gradients in chlorophyll-a profiles after summer blooms that take role as the main source of high differences between satellite observations and surface chlorophyll-a concentration. As such, it is important to supplement satellite measurements with vertical profiles to ensure valid readings and exercise caution when dealing with data post-blooms. These instances occurred in less than 3% of all cases. Differences in the phytoplankton community structures have shown direct correlation to estimation error - Miozoa is associated with low error, Bacillariophyta with high error, while Phytoflagellates abundance tips the error between underestimation and overestimation.
•in situ and satellite chla data is compared for uncertainties.•Sources included algorithms, structure of water column and phytoplankton communities.•Global and regional algorithms examined - they are the primary source of uncertainty.•Local algorithm developed from the regional - improvement in accuracy.•Strong chla profiles and some phytoplankton phyla cause error.
The effects of consumption of n-3 polyunsaturated fatty acids (n-3 PUFAs) enriched hen eggs on endothelium-dependent and endothelium-independent vasodilation in microcirculation, and on endothelial ...activation and inflammation were determined in young healthy individuals. Control group (
= 21) ate three regular hen eggs/daily (249 mg n-3 PUFAs/day), and n-3 PUFAs group (
= 19) ate three n-3 PUFAs enriched hen eggs/daily (1053 g n-3 PUFAs/day) for 3 weeks. Skin microvascular blood flow in response to iontophoresis of acetylcholine (AChID; endothelium-dependent) and sodium nitroprusside (SNPID; endothelium-independent) was assessed by laser Doppler flowmetry. Blood pressure (BP), body composition, body fluid status, serum lipid and free fatty acids profile, and inflammatory and endothelial activation markers were measured before and after respective dietary protocol. Results: Serum n-3 PUFAs concentration significantly increased, AChID significantly improved, and SNPID remained unchanged in n-3 PUFAs group, while none was changed in Control group. Interferon-γ (pro-inflammatory) significantly decreased and interleukin-10 (anti-inflammatory) significantly increased in n-3 PUFAs. BP, fat free mass, and total body water significantly decreased, while fat mass, interleukin-17A (pro-inflammatory), interleukin-10 and vascular endothelial growth factor A significantly increased in the Control group. Other measured parameters remained unchanged in both groups. Favorable anti-inflammatory properties of n-3 PUFAs consumption potentially contribute to the improvement of microvascular endothelium-dependent vasodilation in healthy individuals.
Differences in crystallinity, structure and composition variation along the growing direction in gilthead seabream, Sparus aurata otoliths that inhabited different environments were determined to ...evaluate the correlation of spectroscopic and chemical data with the lifetime development and movement pattern. The Raman spectroscopy signal provided the characteristic bands whose Full Width at Half Maximum (FWHM) were used to track the signal variability. The FWHM showed an initial increase in the core area, followed by a decrease depicting two minima coinciding growth rings. The crystal discontinuity linked to annual rings was confirmed. The FWHM pattern followed cycle in the individual's activity. However, no significant correlation with FWHM and environmental factors although the slope of the FWHM variation distinguished aquaculture and costal groups from open sea and transitional, estuarine waters. Raman data were further correlated with morphological and elemental composition obtained via SEM-EDX and by LA-ICP-MS. SEM clearly confirmed CRM findings. Finally, multiparameter analysis of Ba/Ca concentrations obtained by LA-ICP-MS indicated the separation of groups associated with aquaculture and transitional waters due lowest variability in the elemental composition. Other groups are more variable possibly due to the water oligotrophic character and greater variability in prey availability in each environment. Results of the present study showed the additional potential of Raman spectroscopy as a complementary tool for inference of migration or origin of fish based on otolith composition and structure like other well-established technique.
Objectives: We aimed to assess whether a 7-day high-salt (HS) diet affects endothelium-dependent and/or endothelium-independent microvascular function in the absence of changes in arterial blood ...pressure (BP), and to determine whether such microvascular changes are associated with changes in body composition and fluid status in healthy young humans. Materials and Methods: Fifty-three young healthy individuals (28 women and 25 men) were assigned to a 7-day low-salt diet (<3.5 g salt/day) followed by a 7-day HS diet (∼14 g salt/day). Skin microvascular blood flow in response to iontophoresis of acetylcholine (ACh) and sodium nitroprusside (SNP) was assessed by laser Doppler flowmetry, and BP, heart rate (HR), plasma renin activity (PRA), serum aldosterone, serum and 24 h-urine sodium, potassium, urea and creatinine levels, together with body composition and fluid status measurement with a 4-terminal portable impedance analyzer were measured before and after diet protocols. Results: BP, HR, body composition and fluid status were unchanged, and PRA and serum aldosterone level were significantly suppressed after HS diet. ACh-induced dilation (AChID) was significantly impaired, while SNP-induced dilation was not affected by HS diet. Impaired AChID and increased salt intake, as well as impaired AChID and suppressed renin-angiotensin system were significantly positively correlated. Changes in body composition and fluid status parameters were not associated with impaired AChID. Conclusion: 7-day HS diet impairs microvascular reactivity by affecting its endothelium-dependent vasodilation in young healthy individuals. Changes are independent of BP, body composition changes or fluid retention, but are the consequences of the unique effect of HS on endothelial function.
Carnosine is a dipeptide synthesized in the body from β-alanine and L-histidine. It is found in high concentrations in the brain, muscle, and gastrointestinal tissues of humans and is present in all ...vertebrates. Carnosine has a number of beneficial antioxidant properties. For example, carnosine scavenges reactive oxygen species (ROS) as well as alpha-beta unsaturated aldehydes created by peroxidation of fatty acid cell membranes during oxidative stress. Carnosine can oppose glycation, and it can chelate divalent metal ions. Carnosine alleviates diabetic nephropathy by protecting podocyte and mesangial cells, and can slow down aging. Its component, the amino acid beta-alanine, is particularly interesting as a dietary supplement for athletes because it increases muscle carnosine, and improves effectiveness of exercise and stimulation and contraction in muscles. Carnosine is widely used among athletes in the form of supplements, but rarely in the population of cardiovascular or diabetic patients. Much less is known, if any, about its potential use in enriched food. In the present review, we aimed to provide recent knowledge on carnosine properties and distribution, its metabolism (synthesis and degradation), and analytical methods for carnosine determination, since one of the difficulties is the measurement of carnosine concentration in human samples. Furthermore, the potential mechanisms of carnosine's biological effects in musculature, metabolism and on immunomodulation are discussed. Finally, this review provides a section on carnosine supplementation in the form of functional food and potential health benefits and up to the present, neglected clinical use of carnosine.
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