Effects of nerve and fibroblast growth factors on the production of nitric oxide in experimental model of Huntington's disease

The role of nitric oxide (NO) in neurological diseases represents one of the most studied, yet controversial subjects in physiology. The aim was to examine the effects of intrastriatal injection neurotrophins (nerve growth factors-NGF, fibroblast growth factors-FGF) in order to investigate the possible involvement of NO in quinolinic acid (QA) induced striatum toxicity in the rat model of Huntington's disease (HD). QA was administered unilaterally into the striatum of adult Wistar rats in a single dose of 150 nM. The other two groups of animals were pretreated immediately before QA application with NGF and FGF, respectively. Control group was treated with 0.9% saline solution in the same manner. Animals were decapitated 7 days after the treatment. Nitrite levels were significantly decreased both in the ipsi- and contra lateral striatum and forebrain cortex of NGF- and FGF-treated animals compared with QA treatment. These results indicated a temporal and spatial propagation of oxidative stress and spread protective effects of NGF and FGF on the forebrain cortex, the distant structure, but tightly connected with striatum, the place of direct neurotoxin damage. Neurotrophins could be the potential neuroprotective agents in HD

Dehydration-related changes of peroxidase and polyphenol oxidase activity in fronds of the resurrection fern Asplenium ceterach L.

Asplenium ceterach belongs to a group of poikilohydric ferns and it can recover uninjured from an almost completely dehydrated state. In our study, short term dehydration (24h) at four different water potentials, resulted in moderate water loss (partial desiccation) in fern tissue. The main phenolic acids represented in A. ceterach were chlorogenic (CGA) and caffeic acid (CA) and their content decreased during the dehydration process. For the first time, peroxidase (POD) and polyphenol oxidase (PPO) isoforms were determined in the rustyback fern. The results exhibit the presence of numerous anionic POD isoforms, with pI ranging from 4.4 to 5.8, but none of the cationic isoforms was detected. Two PPO isoforms were identified, one anionic with pI 6.3 and one cationic with pI of about 9.0. Short-term dehydration brought about a remarkable increase in POD and PPO activity using CGA as a substrate. Changes in enzyme activity and content of substrates during dehydration may play an important role in the adaptation of the rustyback fern to water deficit, and increase the overall plant resistance to stress conditions.nul

Dehydration-related changes of peroxidase and polyphenol oxidase activity in fronds of the resurrection fern Asplenium ceterach L.

Asplenium ceterach belongs to a group of poikilohydric ferns and it can recover uninjured from an almost completely dehydrated state. In our study, short term dehydration (24h) at four different water potentials, resulted in moderate water loss (partial desiccation) in fern tissue. The main phenolic acids represented in A. ceterach were chlorogenic (CGA) and caffeic acid (CA) and their content decreased during the dehydration process. For the first time, peroxidase (POD) and polyphenol oxidase (PPO) isoforms were determined in the rustyback fern. The results exhibit the presence of numerous anionic POD isoforms, with pI ranging from 4.4 to 5.8, but none of the cationic isoforms was detected. Two PPO isoforms were identified, one anionic with pI 6.3 and one cationic with pI of about 9.0. Short-term dehydration brought about a remarkable increase in POD and PPO activity using CGA as a substrate. Changes in enzyme activity and content of substrates during dehydration may play an important role in the adaptation of the rustyback fern to water deficit, and increase the overall plant resistance to stress conditions.nul

High-density ceramics obtained by andesite basalt sintering

In the present study, andesite basalt originated from the deposit site “Donje Jarinje”, Serbia, was examined as a potential raw material for high-density ceramics production. The production of high-density ceramics included dry milling, homogenization, cold isostatic pressing and sintering in the air. To determine the optimal processing parameters the sintering was conducted at 1040, 1050, 1060, 1070 and 1080°C, and afterwards the sintering duration was varied from 30 to 240min at the optimal sintering temperature of 1060°C. Characterization of the starting and sintered materials included the estimation of particle size distribution, density, hardness and fracture toughness complemented with X-ray diffraction, optical light microscopy, scanning electron microscopy and energy dispersive spectroscopy analysis. Phase transformations did not occur during processing in the investigated temperature range from 1040 to 1080°C. The obtained research results showed that 99.5% of relative density and the highest hardness and fracture toughness values of 6.7GPa and 2.2MPa•m1/2, respectively, were achieved for the andesite basalt sintered at 1060°C for 60min in the air. The results of the present study confirmed that the sintered andesite basalt can be used as a high-density ceramic material for various industrial applications

The Recasting Effects on the High Gold Dental Alloy Properties

Noble dental alloys are often reused in dental practice by recasting. The aim of this study was to determine if repeated casting of high gold dental alloys has a detrimental effect on alloy microstructure, type of porosity, structure and microhardness. Results showed that recasting procedure had a strong effect on the change of alloy porosity type. It was also found that alloy microhardness increased with the increase of the number of recasting cycles. At the same time the grain growth and changes of the solid solution phases in the microstructure were observed

Supplementary data for the article: Milenković, I.; Mitrović, A.; Algarra, M.; Lázaro-Martínez, J. M.; Rodríguez-Castellón, E.; Maksimović, V.; Spasić, S. Z.; Beškoski, V. P.; Radotić, K. Interaction of Carbohydrate Coated Cerium-Oxide Nanoparticles with Wheat and Pea: Stress Induction Potential and Effect on Development. Plants 2019, 8 (11). https://doi.org/10.3390/plants8110478

Supplementary material for: [https://doi.org/10.3390/plants8110478]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/3698

Design of Pt-Sn-Zn Nanomaterials for Successful Methanol Electrooxidation Reaction

This work highlights the potential for the synthesis of new PtSnZn catalysts with enhanced efficiency and durability for methanol oxidation reaction (MOR) in low-temperature fuel cells. In this research, PtZn and PtSnZn nanoparticles deposited on high surface area Vulcan XC-72R Carbon support were created by a microwave-assisted polyol method. The electrochemical performances of synthesized catalysts were analyzed by cyclic voltammetry and by the electrooxidation of adsorbed CO and the chronoamperometric method. The physicochemical properties of obtained catalysts were characterized by transmission electron microscopy (TEM), thermogravimetric (TGA) analysis, energy dispersive spectroscopy (EDS) and by X-ray diffraction (XRD). The obtained findings showed the successful synthesis of platinum-based catalysts. It was established that PtSnZn/C and PtZn/C catalysts have high electrocatalytic performance in methanol oxidation reactions. Catalysts stability tests were obtained by chronoamperometry. Stability tests also confirmed decreased poisoning and indicated improved stability and better tolerance to CO-like intermediate species. According to activity and stability measurements, the PtSnZn/C catalyst possesses the best electrochemical properties for the methanol oxidation reaction. The observed great electrocatalytic activity in the methanol oxidation reaction of synthesized catalysts can be attributed to the beneficial effects of microwave synthesis and the well-balanced addition of alloying metals in PtSnZn/C catalysts

Recasting as a booster of Ag-Pd alloy cytotoxicity: induction of cell senescence prior to mass cell death

The biological quality and chemical composition of alloys used in dental practice change during heat treatment. Often the residues of the previous cast are not disposed of but are reused and recycled until consumed. Thus, manufactured dental restorations have modified biological quality and chemical composition, and compromised biocompatibility. The aim of this study was to investigate the influence of repeated casting on the cytotoxicity of the silver-palladium (Ag-Pd) alloy. Our results showed that repeated casting of the Ag-Pd dental alloy affected its biocompatibility by promoting toxicity against transformed fibroblasts in a contact-independent manner. A strong decrease in cell proliferation, induction of senescence and massive cell death were observed in cultures exposed only to a medium previously incubated with dental alloy samples. The obtained data indicated that toxicity mediated by the accumulation of the Ag, Pd, Cu and Zn cations released from the Ag-Pd material was enhanced by recasting. The induction of cell senescence and subsequent apoptotic and necrotic death were accompanied by amplified intracellular production of reactive oxygen and nitrogen species, suggesting their involvement in the cell destruction process. Therefore, compromised biocompatibility after recasting with the Ag-Pd alloy can be the cause of serious local cell destruction, as observed in clinical practice

Andesite Basalt as a Natural Raw Material for Obtaining Glass-Ceramics

The industrial requirements in the 21st century are environmentally friendly and light construction materials with good physical-mechanical properties manufactured from cheap natural raw materials available in large quantities. One of these materials is basalt. Basalt is a natural igneous rock of volcanic origin, with a significant amount in Serbia. Basalt belongs to the group of non-hazardous and eco-friendly materials. Andesite basalt aggregate from the "Donje Jarinje" site, Serbia, was used as the starting natural raw material for obtaining the glass-ceramic material. The aggregate is from 2 to 5 mm in size. The aggregate was milled in the tungsten-carbide vibrating cup mill for 30 min to obtain a fine powder for synthesis. The homogenization of andesite basalt powder and binder was carried out in the mortar and pestle for 10 min. The paraplast was used as a binder with a content of 0.6 wt.%. After that, uniaxial pressing of the powder at a pressure of 50 MPa was performed. A forming green compact, cold isostatic pressing was performed with a pressure of 230 MPa to increase its density. The sintering was carried out at the temperature of 1060 °C for 60 min in the air. The sintered glass-ceramic sample was a relative density of 99.5%, a macrohardness of 6.7 GPa and a fracture toughness of 2.2 MPa·m1/2 [1]. The andesite basalt powder was characterized using the laser light diffraction method, X-ray diffraction method and scanning electron microscopy. Sintered glassceramic material was characterized using the X-ray diffraction method, Archimedes principle, scanning electron and optical light microscopy and the Vickers hardness test. The glass-ceramic material obtained by sintering andesite basalt powder could be used for various industrial applications in the civil engineering, mechanical, chemical, and petrochemical industries, as well as for the making of containers to store nuclear waste.VII Conference of The Serbian Society for Ceramic Materials, 7CSCS-2023, June 14-16, 2023, Belgrade, Serbi

CFD Calculation of Helicopter Tail Rotor Airloads for Fatigue Strength Experiments

This work focuses on defining loads and fatigue life estimation of helicopter tail rotor blades. The original metal construction of these blades was replaced with a new construction of blades made from composite materials. The subject of this investigation is the precise determination of loads of helicopter composite tail rotor blades together with experimental verification of their fatigue strength. In this research to determine loads of tail rotor blades computational fluid dynamics (CFD) numerical simulations are used. To study the fatigue behavior of composite blades, the blades are here tested under static and fatigue load spectra. For determination of aerodynamic loads of tail rotor blades in this investigation, two computation models are used. In first model, an isolated tail rotor blade is considered. In the second computation model, the complete helicopter is modeled, including fuselage together with main and tail rotor blades. The tail rotor hub is not included in these computational models. To verify the strength of the composite structure of the tail rotor blade, it is tested under the static load and fatigue load spectra. The experimental fatigue test results under the load spectrum are included