34 research outputs found
Analiza prodrlog elektromagnetskog polja mobilnog telefona korišćenjem numeričkog modela dečije glave za različite mikrotalasne podopsege
The research work presented here was aimed at obtaining the new
results related to the calculation of penetrated electromagnetic field
from a mobile phone and its spatial distribution inside a child’s head.
Several numerical models were developed for the purpose of
investigating the effects of mobile phone radiation. A comprehensive
3D numerical model was developed, which corresponds to the
anatomical and morphological properties of a seven years-old child
head by size and shape. An adult head model was created for the
purpose of examining the different effects of electromagnetic
radiation on children and adults. Also, in line with the trend of
increased use of mobile phones for internet access and
viewing/reading of the content on the device display, a child eye
model with appropriate anatomical and morphological characteristics
was developed to match such use.
The source of electromagnetic radiation has been created to match
the shape of a contemporary smart phone, and it contains the housing
with a display and the antenna. The research involved a simulation of
operational conditions of the phone at several different frequencies –
both at currently used and at upcoming 5G network frequencies.
For assumed level of device output power, high values of electric
field intensity and specific absorption rate (SAR), exceeding the
allowed reference levels and base limitations were found in some
tissues/organs inside the child head model. Higher than allowed
electric field and SAR levels were also found for millimetre wave
frequency ranges but they are concentrated in narrow layers near the
very surface of the model, whereby the exceeding SAR level is even
more noticeable.
Higher values of electric field intensity and SAR are present in the
child head model to a greater extent compared to the adult head
model, due to anatomical and geometrical differences between child
and adult head models. The research also shows that the
morphological properties of children’s tissues and organs influence
the increase of SAR values
Photocatalytic activity of ZnO-PEO composites
The removal of organic pollutants from wastewater is very important for environmental protection. During the years different methods have been developed and applied on wastewater treatment. Between those methods a heterogeneous photocatalysis has received extensive attention since it allows a complete mineralization of pollutants. ZnO-based materials has established role in heterogeneous photocatalysis. However, major drawback of ZnO is a band energy gap of 3.37 eV (368 nm) which restricts the material to absorb only UV light. Since sunlight is a source of clean and cheap energy, where UV light makes no more than 3–5% while visible light is about 45% of the total sunlight, it is highly desirable to synthesize ZnO-based materials capable for visible light photocatalysis. To modify the optical absorption properties and improving the visible light photocatalytic activity of ZnO materials several approaches have been applied: (1) metal ion doping, (2) nonmetal doping, (3) defect induced doping, (4) surface sensitization of ZnO particles to extend the spectral response into the visible region, (5) band gap modification by creation of oxygen vacancies and oxygen sub-stoichiometry, etc. In this study, ZnO powder with nanospherical morphology was synthesized by microwave processing. In the continuation, the synthesized powder was used for preparation of composites with polyethylene oxide (PEO). PEO powders with three different molecular mass (200.000, 600.000 and 900.000) were used for composites preparation. The phase purity and crystal structure of the composites were investigated by X-ray diffraction and Raman spectroscopy. The particles morphology and size distributions were studied by FE–SEM and laser diffraction particle size analyzer, respectively. The optical properties were studied using UV–Vis diffuse reflectance and photoluminescence spectroscopy. The photocatalytic activity of ZnO-PEO composites was examined via decomposition of methylene blue (MB) under direct sunlight irradiation. A large efficiency of MB degradation was found after 6 h of irradiation. An enhanced optical and photocatalytical properties of ZnO-PEO composites were attributed to: (1) lattice defects introduced in crystal structure of ZnO by fast microwave processing, and (2) surface sensitization by polyethylene oxide (PEO)
Development of Grid e-Infrastructure in South-Eastern Europe
Over the period of 6 years and three phases, the SEE-GRID programme has
established a strong regional human network in the area of distributed
scientific computing and has set up a powerful regional Grid infrastructure. It
attracted a number of user communities and applications from diverse fields
from countries throughout the South-Eastern Europe. From the infrastructure
point view, the first project phase has established a pilot Grid infrastructure
with more than 20 resource centers in 11 countries. During the subsequent two
phases of the project, the infrastructure has grown to currently 55 resource
centers with more than 6600 CPUs and 750 TBs of disk storage, distributed in 16
participating countries. Inclusion of new resource centers to the existing
infrastructure, as well as a support to new user communities, has demanded
setup of regionally distributed core services, development of new monitoring
and operational tools, and close collaboration of all partner institution in
managing such a complex infrastructure. In this paper we give an overview of
the development and current status of SEE-GRID regional infrastructure and
describe its transition to the NGI-based Grid model in EGI, with the strong SEE
regional collaboration.Comment: 22 pages, 12 figures, 4 table
Algae as a source of bioactive compounds to prevent the development of type 2 diabetes mellitus
Type 2 diabetes mellitus is a complicated metabolic disorder characterized by hyperglycemia and glucose intolerance. It is considered a new pandemic and its control involves numerous challenges. Although many of the measures are based on improving life habits, diet is also of vital importance due to bioactive compounds present in food. In this regard, several raw materials have been investigated whose bioactivities seem to slow the progression of this disease. Within these matrices, there are algae of importance, such as brown algae, showing to have beneficial effects on glycemic control. These pieces of evidence are increasing every day due to the development of cell or animal models, which lead to the conclusion that bioactive compounds may have direct effects on decreasing hyperglycemia, enhancing insulin secretion and preventing the formation of amyloid plaques.Serbian co-authors thank the Ministry of Education,
Science, and Technological Development of the
Republic of Serbia for the support within the contracts
for the realization and financing of scientific research
work in 2021 ; financial support from Programa de Cooperación
Interreg V-A España—Portugal (POCTEP)
2014–2020; MICINN supporting the Ramón&Cajal
grant for M.A. Prieto; to Xunta de Galicia and University
of Vigo supporting the pre-doctoral grants for
A.G. Pereira, and P. García-Oliveira; to Ibero-American
Program on Science and Technology for financial
support. This project has received funding from the
Bio Based Industries Joint Undertaking (JU); the JU receives
support from the European Union’s Horizon
2020 research and innovation program and the Bio
Based Industries Consortium.info:eu-repo/semantics/publishedVersio
De la variabilité des usages en interaction à des descriptions linguistiques réutilisables : l’exemple de wa-llah
Cet article aborde la question posée dans le numéro « langue, discours, culture » à travers l’analyse de corpus d’interactions en arabe. La formule wallah qui est étudiée a été choisie en raison de la fréquence de son usage, et parce qu’elle correspond à un élément linguistique culturellement spécifique : il s’agit d’un serment signifiant littéralement « par Dieu », répertorié par la tradition grammaticale arabe parmi les procédés de « corroboration » (proche d’une modalité de « renforcement »). L’analyse des 90 occurrences de la formule dans les corpus analysés conduit à distinguer deux types d’usages : les emplois de type « corroboratif », et les emplois dans lesquels la formule s’est figée et fonctionne quasiment à la manière d’une particule discursive. Cet exemple illustre surtout la relation complexe entre langue et culture, telle qu’elle se reflète dans les usages.This paper deals with the question of the inter-relationship between language, discourse and culture which is the guiding theme of this volume via an examination of spoken Arabic in interaction. The expression “wa-llah” has been selected for a descriptive analysis for two reasons : because of its high rate of occurence in spoken Arabic and because it is a culturally specific linguistic item. It is in fact an oath, which literally means “by God”, and which is listed in the Arabic grammatical tradition as a “corroboration” device, a way of adding emphasis. The analysis of the 90 occurences of “wa-llah” that were found in the data leads, in fact, to drawing a distinction between two separate kinds of usage : Firstly, one that falls into the traditional category of “corroboration” and, secondly, one where the term appears to have been grammaticalized and to work largely as a discourse particle. The analysis of thisparticular example highlights the intricate nature of the relationship between language and culture that emerges from speakers’ usage
Synthesis, cytotoxicity and computational study of novel protoberberine derivatives
A novel and efficient synthetic route was developed for the preparation of protoberberine derivatives. A methodology, designed primarily to control the substitution patterns on the terminal rings, was used to access a small array of these compounds. An initial biological profiling suggested an anticancer potential of the synthesised derivatives, while structure-based target fishing identified their potential targets and established a rational basis for further structural modifications. Although the activities need further improvement, the study demonstrated that the described approach may be useful in the discovery of novel lead compounds
The effects of acute hyperhomocysteinemia induced by DL-homocysteine or DL-homocysteine thiolactone on serum biochemical parameters, plasma antioxidant enzyme and cardiac acetylcholinesterase activities in the rat
The aim of this study was to assess the effects of DL-homocysteine (DL-Hcy) and DL-homocysteine thiolactone (DL-Hcy TLHC) on selected serum biochemical parameters, markers of oxidative stress and the activities of antioxidant enzymes (catalase (CAT), glutathione peroxidase (GPx), superoxide dismutase (SOD)) in the plasma, as well as on acetylcholinesterase (AChE) activity in the cardiac tissue homogenate in the rat. Male Wistar rats were divided into three groups as follows: control group (1 mL 0.9% NaCl, intraperitoneal (i.p.) injection), DL-Hcy group (8 mmol/kg body mass (b.m.), i.p.) or DL-Hcy TLHC group (8 mmol/kg b.m., i.p.). One hour after administration, the rats were euthanized, whole blood was collected for biochemical analysis, and the heart was excised. Following the i.p. administration of DL-Hcy and DL-Hcy TLHC, the activities of antioxidant enzymes were mostly significantly increased, while plasma malondialdehyde (MDA) was decreased. Administration of DL-Hcy and DL-Hcy TLHC significantly inhibited AChE activity in rat cardiac tissue. Our findings suggest that DL-Hcy and DL-Hcy TLHC exerted prooxidant effects; however, the decrease in MDA points to an inverse response to the increase in antioxidant enzyme activities. While both substances inhibited AChE activity in rat cardiac tissue, DL-Hcy TLHC induced stronger effects than DL-Hcy
Curcumin loaded pegylated nanoemulsions designed for maintained antioxidant effects and improved bioavailability: A pilot study on rats
The current study describes the experimental design guided development of PEGylated nanoemulsions as parenteral delivery systems for curcumin, a powerful antioxidant, as well as the evaluation of their physicochemical characteristics and antioxidant activity during the two years of storage. Experimental design setup helped development of nanoemulsion templates with critical quality attributes in line with parenteral application route. Curcumin-loaded nanoemulsions showed mean droplet size about 105 nm, polydispersity index <0.15, zeta potential of −40 mV, and acceptable osmolality of about 550 mOsm/kg. After two years of storage at room temperature, all formulations remained stable. Moreover, antioxidant activity remained intact, as demonstrated by DPPH (IC50 values 0.078–0.075 mg/mL after two years) and FRAPS assays. In vitro release testing proved that PEGylated phospholipids slowed down the curcumin release from nanoemulsions. The nanoemulsion carrier has been proven safe by the MTT test conducted with MRC-5 cell line, and effective on LS cell line. Results from the pharmacokinetic pilot study implied the PEGylated nanoemulsions improved plasma residence of curcumin 20 min after intravenous administration, compared to the non-PEGylated nanoemulsion (two-fold higher) or curcumin solution (three-fold higher). Overall, conclusion suggests that developed PEGylated nanoemulsions present an acceptable delivery system for parenteral administration of curcumin, being effective in preserving its stability and antioxidant capacity at the level highly comparable to the initial findings
New records and noteworthy data of plants, algae and fungi in SE Europe and adjacent regions, 13
This paper presents new records and noteworthy data on the following taxa in SE
Europe and adjacent regions: brown alga Heribaudiella fluviatilis, red alga Batrachospermum skujae, saprotrophic fungus Gnomonia geranii-macrorrhizi, mycorrhizal fungi Amanita alseides and Russula griseascens, liverwort Ricciocarpos natans, moss Blindia acuta, Leucodon sciuroides var. morensis and Pseudostereodon procerrimus, monocots Allium ampeloprasum, Carex ferruginea and Carex limosa and dicots Convolvulus althaeoides, Fumana aciphylla, Hieracium petrovae, Lamium
bifidum subsp. bifidum and Ranunculus fontanus are given within SE Europe and
adjacent region
Anatomija anorektalne regije
Poznavavanje anatomskih struktura i topografskih odnosa posebno je značajno za praksu radiklane i fiziološke kirurgije rektuma i anusa. Tu se podrazumijeva dobro poznavanje rektalne vaskularizacije u normalnim i patološkim uvjetima, topografije limfnog sustava, odgovarajućih vezivnih struktura i sistema inervacije