Vokiečių matematikas Aurelas Edmundas Fosas ir Lietuvos universitetas

Professor Aurel Edmund Voss was a German mathematician, best known for his contributions to application of geometry in natural science and mechanics. The collection of books of professor A.E. Voss was bought and used by Faculty of Matematics and Nature of Univerity of Lithuania. In 1940’s the collection of books of prof. A.E. Voss was transfered to Vilnius University. The aim of the work was to investigate collections of books of libraries of Lithuania and to present books of prof. A.E Voss to scientific society of Lithuania.  Profesorius Aurelas Edmundas Fosas – vokiečių matematikas, šiandien la-biausiai žinomas kaip geometrijos taikymo gamtos moksluose ir mechanikoje pradininkas. Prof. O. Folkui pasiūlius, Lietuvos universiteto Matematikos-gamtos fakultetas įsigijo prof. A.E. Foso knygų kolekciją, kuri daugelį metų buvo naudojama studijoms ir moksliniams dar-bams. 1940 metais sustabdžius Vytauto Didžiojo universiteto Matematikos-gamtos fakulteto veiklą, prof. A.E. Foso knygų kolekcija buvo perkelta į Vilniaus universitetą, o likusios prof. A.E Foso bibliotekos dalies likimas nežinomas. Šio darbo tikslas – atlikti prof. A.E. Foso bibliotekos paieškas Lietuvos bibliotekose ir pateikti tyrimų rezultatus plačiajai mokslo visuo-menei. Atlikus mokslinius tyrimus Kauno technologijos ir Vilniaus universitetų bei Kauno apskrities bibliotekose, nedidelė dalis prof. A.E. Fosui priklausiusių knygų rasta Vilniaus universiteto Matematikos ir informatikos fakulteto bibliotekos fonduose. &nbsp

Matematikos ir gamtos fakultetas Lietuvos universitete ir jo raida

The origins of the Faculty of Mathematics and Natural Sciences in Kaunas are the early 1920, when the Lithuanian Higher Courses were established and included the Mathematical-Physical Department. On the 16th of February 1922, the University of Lithuania was created in Kaunas and the Faculty of Mathematics and Nature was founded as well. It acted up until autumn in 1940. All the time from the very beginning until the suspension, the Dean of the faculty was Professor Zigmas Žemaitis. Later on the 1st of September 1993, the Faculty of Fundamental Sciences was established on the basis of two departments – Kaunas University of Technology Department of Higher Mathematics (later re-named to Department of Applied Mathematics) and Department of General Mathematics and Physics. On the 1st of January, 2014 the faculty received its historical title – the Faculty of Mathematics and Natural Sciences and now is celebrating 25 years of activity.Matematikos ir gamtos fakulteto ištakomis Kaune laikomi 1920-ieji metai, kai buvo įsteigti Lietuvos Aukštieji Kursai, į kurių sudėtį įėjo ir Matematikos-fizikos skyrius. 1922 m. vasario 16~d., įkūrus Lietuvos universitetą Kaune, buvo įsteigtas Matematikos-gamtos fakultetas, kuris vykdė veiklą iki 1940 m. rudens. 1940 m. rugsėjo 1 d. Matematikos-gamtos fakulteto veikla Kaune sustabdyta, jis perkeltas į Vilnių. Visą, nuo Fakulteto įkūrimo iki sustabdymo, veiklos laiką Kaune Fakultetui vadovavo dekanas prof. Zigmas Žemaitis. 1993 m. rugsėjo 1 d. Kauno technologijos universitete Aukštosios matematikos (pakeičiant pavadinimą į Taikomosios matematikos), Bendrosios matematikos ir Fizikos katedrų pagrindu įsteigtas Fundamentaliųjų mokslų fakultetas, 2014 m. sausio 1 d. (at)gavęs istorinį Matematikos ir gamtos mokslų fakulteto pavadinimą ir skaičiuojantis jau 25-uosius savo veiklos metus

Development and Characterization of Silver Containing Free Standing Polymer FILMS for Dosimetry Applications

Polymer gels and films, due to their near equivalence to biological tissue, are amongst the most promising future dosimetry tools for medical applications. The application of polymer dose gels is limited by the sensitivity of dose readout methods and dose gel properties. It is a challenge to find suitable dosimeters for registration of doses delivered to the target by orthovoltage therapy units. The application of metal-particle-enriched polymer composites for dose registration in X-ray therapy might be an elegant solution, especially if recent dose-reading technologies exploring advantages of different physical phenomena are involved. In this work, X-rays from the orthovoltage therapy range were used for the irradiation of experimental samples. In addition, radiation-induced processes of formation of silver nanoparticles in AgNO3–PVA gels and in free standing AgNO3PVA films, also containing some additional solvents, namely glycerol, ethanol, and isopropanol, have been investigated, with the aim to apply the developed composites for medical dosimetry purposes. A simple and environmentally friendly method for the formation of free-standing AgPVA films at room temperature was proposed and realized for preparing AgPVA films for investigation. Radiation-induced synthesis of silver nanoparticles in AgPVA composites was investigated, analyzing LPSR-based UV-VIS spectral changes to the irradiated films with respect to irradiation doses, and dose-related tendencies were also evaluated. It was shown that AgPVA films were more sensitive for detection of doses from the interval 0–1.0 Gy, thus indicating potential application of AgPVA films for dosimetry purposes

Investigation of the Antimicrobial Properties of Beetroot–Gelatin Films Containing Silver Particles Obtained via Green Synthesis

Silver nanoparticles are produced using various physical, chemical or physicochemical methods. Simple low-cost nontoxic environmentally friendly, or “green”, chemistry methods are important, especially for their invasive application in the medicine and food industries. Silver-nanoparticle-enriched biocompatible films were produced at room temperature from fresh beetroot juice, AgNO3 and gelatin–water solution using the photoreduction method. The optical, morphological and structural characteristics of the experimental samples were analyzed using UV-VIS, XRD and SEM techniques. The antimicrobial activity of newly produced films was investigated using the agar diffusion method. The synthesis of nanoparticles was approved their characteristic LSPR peaks in the UV-VIS absorbance spectra. According to the XRD patterns of the films, these nanoparticles were assigned to the cubic phase of metallic Ag. It was found that the antimicrobial activity of the silver nanoparticles in the beetroot–gelatin films might be effective; however, it depends on the silver ion concentrations used for the production of these films and on the medium’s pH

Investigation of the antimicrobial properties of beetroot–gelatin films containing silver particles obtained via green synthesis

Silver nanoparticles are produced using various physical, chemical or physicochemical methods. Simple low-cost nontoxic environmentally friendly, or “green”, chemistry methods are important, especially for their invasive application in the medicine and food industries. Silver-nanoparticle-enriched biocompatible films were produced at room temperature from fresh beetroot juice, AgNO3 and gelatin–water solution using the photoreduction method. The optical, morphological and structural characteristics of the experimental samples were analyzed using UV-VIS, XRD and SEM techniques. The antimicrobial activity of newly produced films was investigated using the agar diffusion method. The synthesis of nanoparticles was approved their characteristic LSPR peaks in the UV-VIS absorbance spectra. According to the XRD patterns of the films, these nanoparticles were assigned to the cubic phase of metallic Ag. It was found that the antimicrobial activity of the silver nanoparticles in the beetroot–gelatin films might be effective; however, it depends on the silver ion concentrations used for the production of these films and on the medium’s pH

Application of Red Onion Peel Extract for Green Synthesis of Silver Nanoparticles in Hydrogels Exhibiting Antimicrobial Properties

UV-initiated green synthesis of metal nanoparticles by using plant extracts as photoreducing agents is of particular interest since it is an environmentally friendly, easy-to-maintain, and cost-effective method. Plant molecules that act as reducing agents are assembled in a highly controlled way which makes them suitable for metal nanoparticle synthesis. Depending on the plant species, their application for green synthesis of metal nanoparticles for diverse applications may contribute to the mediation/reduction in organic waste amounts, thus enabling the implementation of the circular economy concept. In this work, UV-initiated green synthesis of Ag nanoparticles in hydrogels and hydrogel’s thin films containing gelatin (matrix), red onion peel extract of different concentrations, water, and a small amount of 1 M AgNO3 have been investigated and characterized using UV-Vis spectroscopy, SEM and EDS analysis, XRD technique, performing swelling experiments and antimicrobial tests using bacteria (Staphylococcus aureus, Acinetobacter baumannii, Pseudomonas aeruginosa), yeasts (Candida parapsilosis, Candida albicans) and microscopic fungi (Aspergillus flavus, Aspergillus fumigatus). It was found that the antimicrobial effectiveness of the silver-enriched red onion peel extract–gelatin films was higher at lower AgNO3 concentrations as compared to those usually used in the commercially available antimicrobial products. The enhancement of the antimicrobial effectiveness was analyzed and discussed, assuming the synergy between photoreducing agent (red onion peel extract) and silver nitrate (AgNO3) in the initial gel solutions leading to the intensification of Ag nanoparticles production

G-11 the model investigation of heavy metals sorption in the Luvisols affected by vehicle pollution

Vytauto Didžiojo universitetasŽemės ūkio akademij

Modification of 3D Printable Polymer Filaments for Radiation Shielding Applications

There is a growing need to develop lead-free shielding materials that are safe, low weight, durable, environmentally friendly, chemically and mechanically stable and customizable for specific applications. Fused deposition modeling (FDM), an additive manufacturing technique based on the extrusion of a thermoplastic filament into a 3D printed object one layer at a time, could be employed well in applications involving ionizing radiation due to its relatively low cost, design flexibility and high manufacturing precision. This study aimed at developing 3D printing composites that contain Titanium dioxide as a filler agent for shielding in a medical radiation environment. First, the effect of low-dose ionizing radiation (up to 15 Gy) on the mechanical properties of common 3D printing polymers, ABS, ULTRAT, PLA, NYLON, ASA and PETG, was investigated. Since ABS experienced the lowest variation in its ultimate tensile strength (±5%) and Young’s modulus (−5%/+11%), it was chosen as a matrix for a new extruded 3D filament containing TiO2 at 1 wt.%, 3 wt.%, and 5 wt.%. With the incorporation of TiO2 at different filler contents, the UTS of the ABS composites varied between 24.1 MPa and 28.4 MPa, with the highest value recorded for 3 wt.% TiO2. Young’s modulus values were dependent on both the TiO2 concentration and on the irradiation dose. In addition, the ABS/TiO2 composites with a higher filler content (3 wt.% and 5 wt.%) maintained their attenuation ability even after exposure to a radiation dose of 100 Gy as opposed to pure ABS, which exhibited a ~2.5% reduction in its mass attenuation coefficient after exposure to the same dose of radiation. The pilot investigation performed demonstrated that the newly developed ABS/TiO2 composite containing 5 wt.% of filler can be successfully employed to shield electronic devices operating in a radiotherapy room