Green synthesis of nanoparticles: Pulsed Laser Ablation in Liquids

Laser ablation synthesis in liquid solution (PLAL) is a green technique that allows for the physical formation of ultrapure nanomaterials. In this work, Ag and Au nanoparticles are synthesized by PLAL using two different neodymium-doped yttrium aluminum garnet (Nd:YAG) laser systems. A pure silver/gold target (99.998% purity) was immersed in Milli-Q water and the sample surface of approximately 1 cm2 in size was continually scanned by a pulsed laser beam to achieve a homogenous ablation. Obtained suspensions were analyzed by ICP-OES, UV-Vis, TEM, and DLS. UV-Vis spectra showed characteristic peaks at 428 nm and 525 nm, which correlate with silver and gold nanoparticles' surface plasmon absorbance. ICP-OES analysis confirmed that these suspensions are free from impurities. Since no stabilizer is added, these nanoparticles tend to agglomerate in time, as TEM and DLS analysis confirmed (Figure 1). Nevertheless, these nanoparticles can be easily functionalized with a variety of ligands such as small molecules, surfactants, dendrimers, polymers, and biomolecules to get desirable functionalities for various applications

Tryptophan metabolites in depression: Modulation by gut microbiota

Clinical depression is a multifactorial disorder and one of the leading causes of disability worldwide. The alterations in tryptophan metabolism such as changes in the levels of serotonin, kynurenine, and kynurenine acid have been implicated in the etiology of depression for more than 50 years. In recent years, accumulated evidence has revealed that gut microbial communities, besides being essential players in various aspects of host physiology and brain functioning are also implicated in the etiology of depression, particularly through modulation of tryptophan metabolism. Therefore, the aim of this review is to summarize the evidence of the role of gut bacteria in disturbed tryptophan metabolism in depression. We summed up the effects of microbiota on serotonin, kynurenine, and indole pathway of tryptophan conversion relevant for understanding the pathogenesis of depressive behavior. Moreover, we reviewed data regarding the therapeutic effects of probiotics, particularly through the regulation of tryptophan metabolites. Taken together, these findings can open new possibilities for further improvement of treatments for depression based on the microbiota-mediated modulation of the tryptophan pathway

Analytical capabilities of TEA CO2 laser based - LIBS setup

Laser-Induced Breakdown Spectroscopy (LIBS) has become a very popular analytical method given some of its unique features such as applicability to any type of sample, practically no sample preparation, stand-off sensing capability, speed of analysis, and a possibility to analysis even the light elements. In this paper, we present a unique laboratory LIBS setup developed in our research group. This system uses infrared TEA CO 2 laser as the excitation source and time-integrated spatially resolved (TISR) signal detection. In our recent publications, we have demonstrated the potential of using the cost- effective TEA CO 2 based LIBS system not only for the fast elemental analysis but also for the simultaneous determination of hardness of materials

Action of pulsed lasers on titanium target: surface effects

The interaction of lasers with metals has been studied for decades, and has been especially intensified lately, due to the development of new, efficient pulsed lasers. Titanium has a number of excellent properties, making it applicable in various modern technologies. Treatment and processing of titanium is possible with various techniques, and the application of lasers gives a special quality, such as high precision machining or obtaining specific structures on the surface which cannot be generated by other methods. During our research, surface processing of titanium was conducted by various pulsed lasers: nanosecond CO2 laser, picosecond Nd:YAG laser and femtosecond Ti: sapphire laser. In order to find the optimal conditions for surface modification of titanium, the influence of different laser parameters (wavelength, pulse duration, pulse energy, etc.), as well as the influence of the ambient, was examined. The titanium samples were irradiated in different environments, ie. in air, oxygen, nitrogen, carbon dioxide, helium and in vacuum, which affected the chemical composition and morphology of the target surface.SPIG 2022 : 31st Summer School and International Symposium on the Physics of Ionized Gases : Contributed papers and abstracts of invited lectures, topical invited lectures and progress reports; September 5-9,2022, Belgrad

Antifungalna aktivnost hitosana prema Alternaria alternata i Colletotrichum gloeosporoides

Chitosan and its derivatives have been reported as a promising alternative for control of postharvest fungal pathogens. The objective of this study was to evaluate in vitro and in situ antifungal activity of chitosan against Alternaria alternata and Colletotrichum gloeosporioides isolated from decayed apple fruits. The fungi were tested in vitro using PDA medium with three concentrations of chitosan (1, 2 and 3 mg/ml). Fungal growth of the test pathogens was significantly affected by all chitosan doses (P lt 0.05) after 7 days of incubation at 25°C. Water solution of 3 mg/ml of chitosan inhibited completely the conidial germination of A. alternata and C. gloeosporioides after 18 h incubation at 25°C. The results obtained from biocontrol assay indicate that the inhibition of postharvest decay of A. alternata and C. gloeosporioides was significantly influenced by chitosan concentrations. Disease incidence in chitosan-treated fruit after 7 days incubation at 25°C was significantly lower than in the positive control for both fungi tested (P lt 0.05). A. alternata and C. gloeosporioides used in this study were progressively inhibited in vitro and in situ with increasing concentrations of chitosan from 1 to 3 mg/ml.Istraživanja pokazuju da su hitosan i njegovi derivati dobra alternativa u kontroli skladišnih fitopatogenih gljiva. Cilj ovog rada bio je da ispita antifungalnu aktivnost hitosana prema Alternaria alternata i Colletotrichum gloeosporoides, izolovanih sa inficiranih plodova jabuke, u in vitro i in situ uslovima. Rast gljiva je testiran in vitro koristeći PDA podlogu sa različitim koncentracijama hitosana (1, 2 i 3 mg/ml). Porast oba patogena je bio značajno smanjen (P lt 0.05) u svim koncentracijama hitosana nakon 7 dana inkubacije na 25°C. Vodeni rastvor hitosana koncentracije 3 mg/ml je u potpunosti inhibirao klijanje konidija A. alternata i C. gloeosporoides nakon inkubacije od 18 sati na temperaturi od 25°C. Rezultati ogleda in situ ukazuju da inhibicija propadanja plodova inficiranih sa A. alternata i C. gloeosporoides zavisi od koncentracije rastvora hitosana. Pojava bolesti na plodovima jabuka tretiranih rastvorom hitosana nakon 7 dana inkubacije na 25°C bila je značajno smanjena za obe vrste gljiva (P lt 0.05) u odnosu na pozitivnu kontrolu. Rast A. alternata i C. gloeosporoides je bio progresivno inhibiran in vitro i in situ sa povećanjem koncentracije rastvora hitosana, od 1 do 3 mg/ml

Stabilizacija prašinaste gline primenom pepela iz termoelektrane "Kolubara", Srbija

U radu su prikazani neki rezultati laboratorijskih ispitivanja stabilizacije prašinaste gline primenom elektrofilterskog pepela iz termoelektrane "Kolubara". Vršena su ispitivanja fizičkih i mehaničkih karakteristika tla, kao što su: granulometrijski sastav, granice konzistencije, odnos vlažnosti i suve zapreminske težine, jednoaksijalna čvrstoća, parametri smičuće čvrstoće, CBR i moduli deformabilnosti. Rezultati istraživanja su pokazali da se primenom pepela kao stabilizatora povećava CBR vrednost tla, što je naročito značajno za primenu u putogradnji

Nova sorta crvene deteline Kolubara

This paper has been prepared on the basis of results from the experiment network of the Yugoslav Center for Agriculture and Forestry, Belgrade. Experiments with red clovers were conducted in three locations in the period 1996-1998. The red clover variety Kolubara was developed at the Institute of Field and Vegetable Crops in Novi Sad. The variety has good tillering, overwintering and regeneration capacities. It is resistant to major diseases: Sclerotinia trifoliorum, Erysiphe communis and Gleosporium spp. In the three-year experiments conducted in three locations, Kolubara produced up to 13 t.ha-1 of dry matter. When mown at the optimum time (beginning of flowering of primary inflorescences), it had the protein content of 18.82% and the crude protein content of 3.267 kg.ha-1. Based on the performances of the new variety, which excelled the standard variety K-9 in the important agronomic characteristics, the Federal Ministry of Agriculture approved the red clover variety Kolubara.Sorta crvene deteline Kolubara stvorena je u Institutu za ratarstvo i povrtarstvo u Novom Sadu. U radu se iznose glavne karakteristike i agronomska svojstva sorte Kolubare u odnosu na standardnu sortu K-9. Kolubara je srednje rana sorta crvene deteline i poseduje dobru moć regeneracije. Odlikuje se dobrim bokorenjem i prezimljavanjem. U trogodišnjim ispitivanjima, na tri različita lokaliteta sorta Kolubara je dala visok prinos suve materije (13 t.ha-1) i sirovih proteina 3.267 kg.ha-1. Imajući u vidu postignute rezultate, Savezno ministarstvo za poljoprivredu je priznalo sortu crvene deteline Kolubaru, 2000. godine, pošto u važnijim osobinama nadmašuje standard K-9

Određivanje dinamičkih karakteristika tla

U ovom radu opisano je određivanje dinamičkih karakteristika tla za ekvivalentnu 1D linearnu analizu dinamičkog odgovora. Istraživanja u ovoj oblasti pokazala su da ovakva analiza daje rezultate koji su u skladu sa merenim vrednostima, pod uslovom da su zadovoljene odgovarajuće pretpostavke i da su dinamičke karakteristike pravilno definisane. Do danas je razvijeno više terenskih i laboratorijskih metoda za određivanje dinamičkih karakteristika tla, kao i veliki broj empirijskih formula