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Iskalni niz: "ključne besede" (nickel) .

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Recombination of oxygen atoms on the surface of oxidized polycrystalline nickel—temperature and pressure dependences
Domen Paul, Miran Mozetič, Rok Zaplotnik, Jernej Ekar, Alenka Vesel, Gregor Primc, Denis Đonlagić, 2023, izvirni znanstveni članek

Povzetek: The recombination of neutral oxygen atoms in the ground state on the oxidized nickel samples was studied experimentally in the range of pressures where the maximum density occurs in weakly ionized low-pressure oxygen plasma, i.e. between 40 and 200 Pa. The recombination coefficient was determined in the flowing afterglow. The source of oxygen atoms was plasma sustained in a quartz tube of inner diameter 4.7 mm by a microwave discharge in the surfatron mode. The recombination coefficient was determined in the afterglow chamber, which was a Pyrex tube with an inner diameter of 36 mm. The density of oxygen atoms in the afterglow chamber was varied by adjusting the discharge power, the gas flow, the pressure, and the position of a recombinator. Such flexibility of the experimental system enabled adjustment of the temperature of the oxidized nickel samples independently from the O-atom density in its vicinity or other parameters. The density of oxygen atoms in the afterglow chamber at various system parameters was determined by the Šorli method, which is reliable, and has an accuracy of about 20%. The recombination coefficient was determined by calorimetry. The coefficient was inversely proportional to the square root of the pressure and exponentially to the sample temperature. Systematic measurements performed at various pressures and temperatures enabled empirical formula, which were explained qualitatively by recombination kinetics.
Ključne besede: heterogenous surface recombination, recombination coefficient, nickel, nickel oxide, temperature
Objavljeno v DiRROS: 30.08.2023; Ogledov: 404; Prenosov: 229
.pdf Celotno besedilo (2,44 MB)
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IoT electrochemical sensor with integrated ▫$Ni(OH)_2–Ni$▫ nanowires for detecting formaldehyde in tap water
Špela Trafela, Abhilash Krishnamurthy, Kristina Žagar, Urška Kavčič, Igor Karlovits, Beno Klopčič, Sašo Šturm, Kristina Žužek Rožman, 2023, izvirni znanstveni članek

Povzetek: Simple, low-cost methods for sensing volatile organic compounds that leave no trace and do not have a detrimental effect on the environment are able to protect communities from the impacts of contaminants in water supplies. This paper reports the development of a portable, autonomous, Internet of Things (IoT) electrochemical sensor for detecting formaldehyde in tap water. The sensor is assembled from electronics, i.e., a custom-designed sensor platform and developed HCHO detection system based on Ni(OH)2–Ni nanowires (NWs) and synthetic-paper-based, screen-printed electrodes (pSPEs). The sensor platform, consisting of the IoT technology, a Wi-Fi communication system, and a miniaturized potentiostat can be easily connected to the Ni(OH)2–Ni NWs and pSPEs via a three-terminal electrode. The custom-made sensor, which has a detection capability of 0.8 µM/24 ppb, was tested for an amperometric determination of the HCHO in deionized (DI) and tap-water-based alkaline electrolytes. This promising concept of an electrochemical IoT sensor that is easy to operate, rapid, and affordable (it is considerably cheaper than any lab-grade potentiostat) could lead to the straightforward detection of HCHO in tap water.
Ključne besede: formaldehyde, electrochemical sensor, nickel, tap water
Objavljeno v DiRROS: 06.06.2023; Ogledov: 466; Prenosov: 191
.pdf Celotno besedilo (2,65 MB)
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Quantitative, absolute count-based T cell analysis of CD69 upregulation as a new methodology for in vitro diagnosis of delayed-type nickel hypersensitivity
Ana Koren, Mira Šilar, Helena Rupnik, Mihaela Zidarn, Peter Korošec, 2019, izvirni znanstveni članek

Povzetek: Background: T cells play a major role in delayed-type hypersensitivity reactions. Their reactivity can be assessed by measuring the upregulation of the activation marker CD69, followed by proliferation and cytokine production. The aim of our study was to develop a novel, whole blood-based, quantitative, absolute count activation index (AI) analysis of CD69 upregulation on different subsets of T cells in nickel hypersensitive patients and compare it with the previously reported approaches. Methods: Ten patients with nickel allergy and nine healthy controls were included. CD69 expression of CD3+, CD3+CD4+ and CD3+CD8+ T cells in heparinized blood was determined with flow cytometry after incubation with nickel sulfate for 48 h. The absolute cell count of CD69+ cells was determined with microbeads. The production of the cytokines IL-2, IL-5, IL-13, and IFN-[gamma] was determined after nickel sulfate stimulation of PBMNCs for 48 h. Results: We showed that the most sensitive methodology is the absolute AI, which was calculated as the ratio between the absolute count of CD69-positive T cells stimulated with nickel and the absolute count of CD69-positive T cells in non-stimulated blood. This novel quantitative approach was more discriminative than the previously reported approaches in which T cell CD69 percentage AI and cytokine production are measured. Conclusions: Our results demonstrated that measuring the absolute CD69 AI is an accurate new approach to quantify antigen-specific T cells in the blood of patients with hypersensitivity reactions to nickel. This approach may be useful for better in vitro assessment of patients with delayed-type hypersensitivity reactions.
Ključne besede: allergy and immunology, delayed hypresensitivity, nickel, blood, CD antigenes, CD69
Objavljeno v DiRROS: 18.11.2020; Ogledov: 1283; Prenosov: 336
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The hazard assessment of nanostructured CeO [sub] 2-based mixed oxides on the zebrafish Danio rerio under environmentally relevant UV-A exposure
Anita Jemec Kokalj, Petar Djinović, Ilja Gasan Osojnik Črnivec, Albin Pintar, 2015, izvirni znanstveni članek

Povzetek: The effect of nanomaterials on biota under realistic environmental conditions is an important question. However, there is still a lack of knowledge on how different illumination conditions alter the toxicity of some photocatalytic nanomaterials. We have investigated how environmentally relevant UV-A exposure (intensity 8.50 ± 0.61 W/m2, exposure dose 9.0 J/cm2) affected the toxicity of cerium oxide (CeO2)-based nanostructured materials to the early-life stages of zebrafish Danio rerio. Pure cerium oxide (CeO2), copper–cerium (CuO–CeO2) (with a nominal 10, 15 and 20 mol.% CuO content), cerium–zirconium (CeO2–ZrO2) and nickel and cobalt (Ni–Co) deposited over CeO2–ZrO2 were tested. It was found that under both illumination regimes, none of the tested materials affected the normal development or induced mortality of zebrafish early-life stages up to 100 mg/L. Only in the case of CuO–CeO2, the growth of larvae was decreased (96 h LOEC values for CuCe10, CuCe15 and CuCe20 were 50, 50 and 10 mg/L, respectively). To conclude, CeO2-based nanostructured materials are not severely toxic to zebrafish and environmentally relevant UV-A exposure does not enhance their toxicity.
Ključne besede: Nickel cobalt nanocrystalline catalysts, UV-A phototoxicity, UV-shielding, zebrafish
Objavljeno v DiRROS: 16.12.2014; Ogledov: 9246; Prenosov: 647
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