This page has only limited features, please log in for full access.
Because the SARS-CoV-2 virus primarily spreads through droplets and aerosols, a protective box could provide adequate protection by shielding medical professionals during the intubation and extubation procedures from generated droplets and aerosols. In this study, size- and time-dependent aerosol concentrations were measured inside and outside the protective box in the particle size ranging from 14 nm to 20 μm during simulated intubation and extubation procedures. An improved protective box with active ventilation was designed based on a plastic bag with armholes covered with latex sheets that utilizes a supportive frame. Coughing during the intubation and extubation procedure was simulated using an aerosol generator which dispersed the aerosol powder into the protective box. During the intubation and extubation procedure, the concentration of particles increased inside the protective box but, due to the high negative airflow, quickly dropped to background levels. The particle concentration of all measured particle sizes decreased within the same time frame. No leakage of particles was observed through the armhole openings. The presented protective box design provides excellent protection against generated droplets and aerosols. The decrease in concentration does not depend on the particle size. Outside the box, particle concentration did not change with time.
Luka Pirker; Metod Čebašek; Matej Serdinšek; Maja Remškar. Size- and Time-Dependent Aerosol Removal from a Protective Box during Simulated Intubation and Extubation Procedures. COVID 2021, 1, 315 -324.
AMA StyleLuka Pirker, Metod Čebašek, Matej Serdinšek, Maja Remškar. Size- and Time-Dependent Aerosol Removal from a Protective Box during Simulated Intubation and Extubation Procedures. COVID. 2021; 1 (1):315-324.
Chicago/Turabian StyleLuka Pirker; Metod Čebašek; Matej Serdinšek; Maja Remškar. 2021. "Size- and Time-Dependent Aerosol Removal from a Protective Box during Simulated Intubation and Extubation Procedures." COVID 1, no. 1: 315-324.
WnO3n−1 nanotiles, with multiple stoichiometries within one nanotile, were synthesized via the chemical vapour transport method. They grow along the [010] crystallographic axis, with the thickness ranging from a few tens to a few hundreds of nm, with the lateral size up to several µm. Distinct surface corrugations, up to a few 10 nm deep appear during growth. The {102}r crystallographic shear planes indicate the WnO3n−1 stoichiometries. Within a single nanotile, six stoichiometries were detected, namely W16O47 (WO2.938), W15O44 (WO2.933), W14O41 (WO2.928), W13O38 (WO2.923), W12O35 (WO2.917), and W11O32 (WO2.909), with the last three never being reported before. The existence of oxygen vacancies within the crystallographic shear planes resulted in the observed non-zero density of states at the Fermi energy.
Luka Pirker; Bojana Višić; Janez Kovač; Srečo D. Škapin; Maja Remškar. Synthesis and Characterization of Tungsten Suboxide WnO3n−1 Nanotiles. Nanomaterials 2021, 11, 1985 .
AMA StyleLuka Pirker, Bojana Višić, Janez Kovač, Srečo D. Škapin, Maja Remškar. Synthesis and Characterization of Tungsten Suboxide WnO3n−1 Nanotiles. Nanomaterials. 2021; 11 (8):1985.
Chicago/Turabian StyleLuka Pirker; Bojana Višić; Janez Kovač; Srečo D. Škapin; Maja Remškar. 2021. "Synthesis and Characterization of Tungsten Suboxide WnO3n−1 Nanotiles." Nanomaterials 11, no. 8: 1985.
The objective of this study was to explore the possible use of a new combination of two excipients, i.e., nanocrystalline cellulose (NCC) and macroporous silica (MS), as matrix materials for the compounding of dry emulsion systems and the effects these two excipients have on the characteristics of dry emulsion powders produced by the spray drying process. A previously developed liquid O/W nanoemulsion, comprised of simvastatin, 1-oleoyl-rac-glycerol, Miglyol 812 and Tween 20, was employed. In order to comprehend the effects that these two matrix formers have on the spray drying process and on dry emulsion powder characteristics, alone and in combination, a DoE (Design of Experiment) approach was used. The physicochemical properties of dry emulsion samples were characterised by atomic force microscopy, scanning electron microscopy, mercury intrusion porosimetry, energy-dispersive X-ray spectroscopy and laser diffraction analysis. Additionally, total release and dissolution experiments were performed to assess drug release from multiple formulations. It was found that the macroporous silica matrix drastically improved flow properties of dry emulsion powders; however, it partially trapped the oil—drug mixture inside the pores and hindered complete release. NCC showed its potential to reduce oil entrapment in MS, but because of its rod-shaped particles deposited on the MS surface, powder flowability was deteriorated.
Mitja Pohlen; Luka Pirker; Rok Dreu. The Potential of Macroporous Silica—Nanocrystalline Cellulose Combination for Formulating Dry Emulsion Systems with Improved Flow Properties: A DoE Study. Pharmaceutics 2021, 13, 1177 .
AMA StyleMitja Pohlen, Luka Pirker, Rok Dreu. The Potential of Macroporous Silica—Nanocrystalline Cellulose Combination for Formulating Dry Emulsion Systems with Improved Flow Properties: A DoE Study. Pharmaceutics. 2021; 13 (8):1177.
Chicago/Turabian StyleMitja Pohlen; Luka Pirker; Rok Dreu. 2021. "The Potential of Macroporous Silica—Nanocrystalline Cellulose Combination for Formulating Dry Emulsion Systems with Improved Flow Properties: A DoE Study." Pharmaceutics 13, no. 8: 1177.
The metallic-associated adverse local tissue reactions (ALTR) and events accompanying worn-broken implant materials are still poorly understood on the subcellular and molecular level. Current immunohistochemical techniques lack spatial resolution and chemical sensitivity to investigate causal relations between material and biological response on submicron and even nanoscale. In our study, new insights of titanium alloy debris-tissue interaction were revealed by the implementation of label-free high-resolution correlative microscopy approaches. We have successfully characterized its chemical and biological impact on the periprosthetic tissue obtained at revision surgery of a fractured titanium-alloy modular neck of a patient with hip osteoarthritis. We applied a combination of photon, electron and ion beam micro-spectroscopy techniques, including hybrid optical fluorescence and reflectance micro-spectroscopy, scanning electron microscopy (SEM), Energy-dispersive X-ray Spectroscopy (EDS), helium ion microscopy (HIM) and micro-particle-induced X-ray emission (micro-PIXE). Micron-sized wear debris were found as the main cause of the tissue oxidative stress exhibited through lipopigments accumulation in the nearby lysosome. This may explain the indications of chronic inflammation from prior histologic examination. Furthermore, insights on extensive fretting and corrosion of the debris on nm scale and a quantitative measure of significant Al and V release into the tissue together with hydroxyapatite-like layer formation particularly bound to the regions with the highest Al content were revealed. The functional and structural information obtained at molecular and subcellular level contributes to a better understanding of the macroscopic inflammatory processes observed in the tissue level. The established label-free correlative microscopy approach can efficiently be adopted to study any other clinical cases related to ALTR.
Rok Podlipec; Esther Punzón-Quijorna; Luka Pirker; Mitja Kelemen; Primož Vavpetič; Rajko Kavalar; Gregor Hlawacek; Janez Štrancar; Primož Pelicon; Samo Fokter. Revealing Inflammatory Indications Induced by Titanium Alloy Wear Debris in Periprosthetic Tissue by Label-Free Correlative High-Resolution Ion, Electron and Optical Microspectroscopy. Materials 2021, 14, 3048 .
AMA StyleRok Podlipec, Esther Punzón-Quijorna, Luka Pirker, Mitja Kelemen, Primož Vavpetič, Rajko Kavalar, Gregor Hlawacek, Janez Štrancar, Primož Pelicon, Samo Fokter. Revealing Inflammatory Indications Induced by Titanium Alloy Wear Debris in Periprosthetic Tissue by Label-Free Correlative High-Resolution Ion, Electron and Optical Microspectroscopy. Materials. 2021; 14 (11):3048.
Chicago/Turabian StyleRok Podlipec; Esther Punzón-Quijorna; Luka Pirker; Mitja Kelemen; Primož Vavpetič; Rajko Kavalar; Gregor Hlawacek; Janez Štrancar; Primož Pelicon; Samo Fokter. 2021. "Revealing Inflammatory Indications Induced by Titanium Alloy Wear Debris in Periprosthetic Tissue by Label-Free Correlative High-Resolution Ion, Electron and Optical Microspectroscopy." Materials 14, no. 11: 3048.
A one-step method for plasma synthesis of nitrogen-doped carbon nanomesh is presented. The method involves a molten polymer, which is a source of carbon, and inductively coupled nitrogen plasma, which is a source of highly reactive nitrogen species. The method enables the deposition of the nanocarbon layer at a rate of almost 0.1 µm/s. The deposited nanocarbon is in the form of randomly oriented multilayer graphene nanosheets or nanoflakes with a thickness of several nm and an area of the order of 1000 nm2. The concentration of chemically bonded nitrogen on the surface of the film increases with deposition time and saturates at approximately 15 at.%. Initially, the oxygen concentration is up to approximately 10 at.% but decreases with treatment time and finally saturates at approximately 2 at.%. Nitrogen is bonded in various configurations, including graphitic, pyridinic, and pyrrolic nitrogen.
Alenka Vesel; Rok Zaplotnik; Gregor Primc; Luka Pirker; Miran Mozetič. One-Step Plasma Synthesis of Nitrogen-Doped Carbon Nanomesh. Nanomaterials 2021, 11, 837 .
AMA StyleAlenka Vesel, Rok Zaplotnik, Gregor Primc, Luka Pirker, Miran Mozetič. One-Step Plasma Synthesis of Nitrogen-Doped Carbon Nanomesh. Nanomaterials. 2021; 11 (4):837.
Chicago/Turabian StyleAlenka Vesel; Rok Zaplotnik; Gregor Primc; Luka Pirker; Miran Mozetič. 2021. "One-Step Plasma Synthesis of Nitrogen-Doped Carbon Nanomesh." Nanomaterials 11, no. 4: 837.
Size- and time-dependent particle removal efficiency (PRE) of different protective respiratory masks were determined using a standard aerosol powder with the size of particles in the range of an uncoated SARS-CoV-2 virus and small respiratory droplets. Number concentration of particles was measured by a scanning mobility particle sizer. Respiratory protective half-masks, surgical masks, and cotton washable masks were tested. The results show high filtration efficiency of FFP2, FFP3, and certified surgical masks for all sizes of tested particles, while protection efficiency of washable masks depends on their constituent fabrics. Measurements showed decreasing PRE of all masks over time due to transmission of nanoparticles through the mask-face interface. On the other hand, the PRE of the fabric is governed by deposition of the aerosols, consequently increasing the PRE.
Anja Pogačnik Krajnc; Luka Pirker; Urška Gradišar Centa; Anton Gradišek; Igor Mekjavic; Matej Godnič; Metod Čebašek; Tina Bregant; Maja Remškar. Size- and Time-Dependent Particle Removal Efficiency of Face Masks and Improvised Respiratory Protection Equipment Used during the COVID-19 Pandemic. Sensors 2021, 21, 1567 .
AMA StyleAnja Pogačnik Krajnc, Luka Pirker, Urška Gradišar Centa, Anton Gradišek, Igor Mekjavic, Matej Godnič, Metod Čebašek, Tina Bregant, Maja Remškar. Size- and Time-Dependent Particle Removal Efficiency of Face Masks and Improvised Respiratory Protection Equipment Used during the COVID-19 Pandemic. Sensors. 2021; 21 (5):1567.
Chicago/Turabian StyleAnja Pogačnik Krajnc; Luka Pirker; Urška Gradišar Centa; Anton Gradišek; Igor Mekjavic; Matej Godnič; Metod Čebašek; Tina Bregant; Maja Remškar. 2021. "Size- and Time-Dependent Particle Removal Efficiency of Face Masks and Improvised Respiratory Protection Equipment Used during the COVID-19 Pandemic." Sensors 21, no. 5: 1567.
Ionizing radiation has been identified as an option for sterilization of disposable filtering facepiece respirators in situations where the production of the respirators cannot keep up with demand. Gamma radiation and high energy electrons penetrate deeply into the material and can be used to sterilize large batches of masks within a short time period. In relation to reports that sterilization by ionizing radiation reduces filtration efficiency of polypropylene membrane filters on account of static charge loss, we have demonstrated that both gamma and electron beam irradiation can be used for sterilization, provided that the respirators are recharged afterwards.
Luka Pirker; Anja Pogačnik Krajnc; Jan Malec; Vladimir Radulović; Anton Gradišek; Andreja Jelen; Maja Remškar; Igor B. Mekjavić; Janez Kovač; Miran Mozetič; Luka Snoj. Sterilization of polypropylene membranes of facepiece respirators by ionizing radiation. Journal of Membrane Science 2020, 619, 118756 -118756.
AMA StyleLuka Pirker, Anja Pogačnik Krajnc, Jan Malec, Vladimir Radulović, Anton Gradišek, Andreja Jelen, Maja Remškar, Igor B. Mekjavić, Janez Kovač, Miran Mozetič, Luka Snoj. Sterilization of polypropylene membranes of facepiece respirators by ionizing radiation. Journal of Membrane Science. 2020; 619 ():118756-118756.
Chicago/Turabian StyleLuka Pirker; Anja Pogačnik Krajnc; Jan Malec; Vladimir Radulović; Anton Gradišek; Andreja Jelen; Maja Remškar; Igor B. Mekjavić; Janez Kovač; Miran Mozetič; Luka Snoj. 2020. "Sterilization of polypropylene membranes of facepiece respirators by ionizing radiation." Journal of Membrane Science 619, no. : 118756-118756.
Quasi-two-dimensional tungsten oxide stoichiometric phases, W18O53, W17O50, W16O47, W15O44, W14O41, W10O29, and W9O26 were identified. It was determined that they nucleate by epitaxial growth on the W19O55 nanowires and grow as thin platelets.
Luka Pirker; Bojana Višić; Srečo D. Škapin; Goran Dražić; Janez Kovač; Maja Remškar. Multi-stoichiometric quasi-two-dimensional WnO3n−1 tungsten oxides. Nanoscale 2020, 12, 15102 -15114.
AMA StyleLuka Pirker, Bojana Višić, Srečo D. Škapin, Goran Dražić, Janez Kovač, Maja Remškar. Multi-stoichiometric quasi-two-dimensional WnO3n−1 tungsten oxides. Nanoscale. 2020; 12 (28):15102-15114.
Chicago/Turabian StyleLuka Pirker; Bojana Višić; Srečo D. Škapin; Goran Dražić; Janez Kovač; Maja Remškar. 2020. "Multi-stoichiometric quasi-two-dimensional WnO3n−1 tungsten oxides." Nanoscale 12, no. 28: 15102-15114.