Impact of Radiofrequency/Microwave Radiation on Cell and Cytoskeleton Structure

S povećanjem broja korisnika pokretne telefonije raste zabrinutost zbog mogućega štetnog djelovanja radiofrekventnoga mikrovalnog zračenja (RF/MW) na zdravlje čovjeka. Posebno su važni netermalni učinci koji nastaju zbog izlaganja RF/MW zračenju koje ne izaziva porast temperature ciljnog tkiva i/ili stanice ili je taj porast neznatan. Mogući biološki učinci takvog zračenja nedovoljno su istraženi. Brojna in vitro istraživanja pokazala su da RF/MW zračenje, čak i unutar dopuštene razine izlaganja, mogu djelovati na staničnu membranu, aktivnost gena, programiranu staničnu smrt, a može uzrokovati i stanični stres. Međutim, učinci RF/MW na neke stanične strukture još su gotovo potpuno nepoznati. Tako je učinak zračenja na citoskelet, koji je funkcionalni i strukturalni dio stanice, slabo istražen. Citoskelet je sastavljen od aktina, intermedijalnih filamenata i mikrotubula. Uloga mikrotubula leži u upravljanju rasporedom staničnih organela, određivanju oblika i polarnosti stanice te vođenju procesa razdvajanja sestrinskih kromatida tijekom somatske diobe stanice, tj. mitoze.The increasing number of mobile phone users raises concern about possible hazardous effects of radiofrequency/microwave (RF/MW) electromagnetic fields. The most intriguing issue is the existence of the so called non-thermal effect which is not related to increased temperature. Possible biological effects, associated with the exposure to RF/MW fields have not been elucidated so far. A number of in vitro studies have attempted to see whether permissible levels of RF/MW affect the cell membrane, gene transcription, apoptosis, and whether they induce stress. However, the effect of RF/MW on the cytoskeleton, one of the most important cell structures, remains unknown. Cytoskeleton is a functional and structural part of the cell, composed of actin, intermedial filaments and microtubules. Microtubules direct the distribution of cellular organelles, determine cell shape, cell polarity and segregation of chromosomes during mitosis

Usporedba djelovanja mikrovalnog zračenja frekvencija 864 MHz i 935 MHz na stanice u kulturi

The objective of this study was to compare the effects of 864 MHz and 935 MHz radiofrequency/microwave radiation on the ability of V79 cells to proliferate, form colonies and on their viability. For one, two and three hours, the cells were exposed to the 864 MHz field in a transversal electromagnetic mode cell (TEM) connected with amplifier and to the 935 MHz field in a gigahertz transversal electromagnetic mode cell (GTEM) equipped with a signal generator. The average specific absorption rate (SAR) was 0.08 W kg-1 for the 864 MHz field and 0.12 W kg-1 for the 935 MHz field. In comparison to the control cell samples, the growth curve of the 864 MHz irradiated cells showed a significant decrease after two-hour and three-hour exposure on the Day 3 after exposure. Likewise, cells exposed to 935 MHz microwaves for three hours showed a significant growth on Day 3 after exposure. The colony-forming ability and viability of cells exposed to 864 MHz and 935 MHz microwaves did not significantly differ from the matched controls. The applied RF/MW fields showed a similar effect on cell culture growth, colony-forming ability and viability of V79 cells.Cilj istraživanja bio je usporediti utjecaj 864 MHz i 935 MHz mikrovalnog zračenja na stanični rast, sposobnost stvaranja kolonija (CFA) i vijabilnost trajne kulture V79-stanica. Prethodno pripremljeni uzorci stanične kulture izlagani su 1, 2 i 3 sata određenim mikrovalnim poljima. Za frekvenciju 864 MHz upotrijebljena je transverzna elektromagnetska komora (TEM komora) opremljena generatorom i pojačalom signala. Polje frekvencije 935 MHz stvoreno je s pomoću gigahercne transverzne elektromagnetske komore (GTEM komora) i generatora signala. Prosječna vrijednost specifične brzine apsorpcije (SAR) iznosila je 0.08 W kg-1 za 864 MHz te 0.12 W kg-1 za 935 MHz.. Stanice su rasle u standardnim laboratorijskim uvjetima (>80 % vlage, 37 °C, 5 % CO2). Za određivanje krivulje staničnog rasta V79-stanice su nasađene u koncentraciji od 1x104 mL-1 hranjivog medija. Iz početne koncentracije od 200 nasađenih stanica sedam dana nakon ozračivanja određena je CFA za svako vrijeme izloženosti brojem nastalih staničnih kolonija. Vijabilnost stanica određena je nakon 1, 2 i 3 sata izloženosti RF/MW poljima s pomoću tripanskog plavila. Vijabilnost je utvrđena omjerom živih i mrtvih stanica tijekom 5 uzastopnih dana pokusa. Rast stanica izloženih 2 i 3 sata polju frekvencije 864 MHz bio je značajno inhibiran treći dan nakon izlaganja, a polje frekvencije 935 MHz je u trosatnoj izloženosti uzoraka uzrokovalo značajan pad broja stanica samo trećeg dana. CFA i vijabilnost stanica izloženih poljima od 864 MHz i 935 MHz nisu se značajno razlikovale od odgovarajućih sham izloženih uzoraka. Mikrovalna polja spomenutih osobina djelovala su na gotovo istovjetan način na rast stanične kulture, sposobnost stvaranja kolonija i vijabilnost V79-stanica

Promjena strukture mikrotubula nakon izloženosti GSM-moduliranom RF zračenju

The objective of the study was to investigate whether low-level 915 MHz GSM-modulated radiofrequency (RF) radiation impairs microtubular structure and affects normal cell growth. V79 cells were exposed to a GSM-modulated field in a Gigahertz Transversal Electromagnetic Mode cell (GTEM cell) for 1, 2, and 3 h. Signal generator combined with power and chip modulator generated the electromagnetic field (EMF). The electric field strength was adjusted to 10, 20, and 30 V/m, and the average specific absorption rate (SAR) was calculated to be 0.23, 0.8, and 1.6 W/kg. The structure of microtubule proteins was assessed by indirect immunocytochemistry, and cell growth was determined based on cell counts taken every day over six post-exposure days. Three-hour radiation exposure significantly altered microtubule structure regardless of the electric field strength. Moreover, on the third post-exposure day, three-hour radiation significantly reduced cell growth, regardless of field strength. The same was observed with two-hour exposure at 20 and 30 V/m. In conclusion, 915 MHz GSM-modulated RF radiation affects microtubular proteins in a time-dependent manner, which, in turn, affects cell proliferation. Our future research will focus on microtubule structure throughout the cell cycle and RF radiation effects on mitotic spindle.Cilj istraživanja bio je ispitati narušava li GSM modulirano radiofrekvencijsko zračenje (RF) frekvencije 915 MHz strukturu mikrotubula te utječe li na rast stanica. Stanice V79 izložene su GSM-moduliranom polju unutar gigahercne transverzalne elektromagnetske komore (GTEM-komora) tijekom jednog, dva i tri sata. Generator signala u kombinaciji s pojačalom i modulatorom signala generirao je elektromagnetsko polje (EMF). Jačina električnoga polja namještena je na vrijednosti od 10, 20 i 30 V/m, a izračunane vrijednosti specifične brzine apsorpcije (SAR) u stanici bile su 0,23, 0,8 i 1,6 W/kg. Struktura mikrotubularnih proteina utvrđena je posrednom imunocitokemijom, a stanični rast određen je na temelju broja stanica izmjerenih za svako vrijeme izloženosti zračenju tijekom šest dana nakon ozračivanja. Značajne promjene u strukturi mikrotubula zabilježene su nakon tri sata zračenja, neovisno o jakosti električnoga polja. Također, značajno smanjen rast stanica zabilježen je tri dana nakon trosatne izloženosti zračenju. Navedene promjene uočene su bez obzira na primijenjenu jakost električnoga polja. Značajno smanjen rast stanica zabilježen je također tri dana nakon dvosatne izloženosti zračenju pri jakosti električnoga polja od 20 i 30 V/m. Možemo zaključiti da je učinak GSMmoduliranoga RF zračenja frekvencije 915 MHz na proteine mikrotubula i stanični rast ovisan o trajanju izloženosti zračenju. Zabilježene promjene bile su izraženije pri višoj jakosti električnoga polja

Natural and cultural landscape of the Vrgorac-Ljubuški region in selected cartographic sources of the 18th century

Nakon višestoljetnoga zajedničkog života u okviru istovjetnih društvenih uvjeta i političkih tvorevina, završetkom ratnih razračunavanja s kraja 17. i drugoga desetljeća 18. stoljeća vrgoračko-ljubuški prostor se našao na periferiji dvaju imperijalnih sustava, na granici njihova dodira. Te su činjenice potaknule proces oblikovanja novih prostorno-regionalnih identiteta kod toga istovjetnog etnokulturnog i etnokonfesionalnog korpusa kakvim ih prepoznajemo danas. Vrgoračko-ljubuški prostor jes predratne periferije Osmanskoga Carstva spomenutim ratnim razgraničenjima podijeljen te uklopljen u vojnokrajiški i osmansko-mletački sustav nastavljajući tako kompleksan historijsko-geografski razvitak s obiju strana granica.After several centuries of living together under identical social circumstances and within the same political entities, at the end of war conflicts in the late 17th century and the second decade of the 18th century, the Vrgorac-Ljubuški area found itself on the periphery of two imperial systems, at the very border between them. These circumstances triggered the process of shaping new regional identities, as we know them today, within this unified ethno-cultural and ethno-confessional corps. The Vrgorac-Ljubuški area, pre-war periphery of the Ottoman Empire, was thus divided according to the aforementioned war demarcations and fitted into the Military Border, Ottoman, and Venetian space, continuing its complex historical and geographic development on both sides of the border

Determining the Transmission Capacity of Existing Transmission Lines Under High Wind Generation Conditions

Determining the transmission capacity of existing transmission lines is determine by the conductor current. Transmission line can withstand current below thermal standpoint limit to avoid irreparable damage to conductor. The maximum value of current can be determined with static approach (STR – Static Thermal Rating) and dynamic approach (DTR - Dynamic Thermal Rating). STR is defined by simple calculations and does not change often throughout the year where the DTR is calculated for in time conditions taking into account atmospheric conditions, conductor geometry and conductor current. Most common approach to calculate conductor temperature is done by applying IEEE standard (IEEE 738, 2012) or CIGRE (TB601, 2014). Most congestion in the transmission network occurs during the higher production from wind farms when the wind have significant speed. It is to be expected that similar meteorological conditions (wind speed and direction) will occur on transmission lines in the immediate geographical area of wind power plants. In this paper, analysis of relations between atmospheric parameters (wind speed and direction, ambient temperature and solar radiation) and ampacity is described as functional dependence. Taking historical weather data from meteorological stations, atmospheric conditions on transmission line corridors and taking account the frequency of occurrence of individual meteorological variations ampacity of conductor will be determined. For such determined conditions that are influenced by a certain parameters variation of ampacity have a different rating scales. The obtained results will provide an insight into the current ampacity and the possibilities of the transmission line capacity during the high engagement of wind power plants

Analysis of the parish register of baptisms of today’s parish Veljaci (1786-1808)

U radu se istražuje demografsko gibanje unutar mikrocjeline Veljaci u općini Ljubuški. U istraživanju je kao izvor primarnih podataka korištena najstarija matična knjiga krštenih s prijelaza iz 18. u 19. stoljeće za prostor koji obuhvaća današnja župa Veljaci. Dobiveni podaci su povijesno-demografskim, mikrohistorijskim i komparativno-historijskim metodološkim pristupom raščlanjeni. Ciljevi istraživanja su predstaviti nekadašnje demografske zbilje ovoga mikroprostora s imperijalne granice, opisati mu demografske pokazatelje i njihovu dinamiku, ponajprije one vezane za natalitet, te uočiti eventualne trendove koji bi upućivali na demografska kretanja širega područja, to jest područje tadašnje župe Ljubuški u cjelini. Ograničenim istraživanjem i analizom podataka prikupljenih pri heurističkim zahvatima za širu i iscrpniju studiju o ljubuškom stanovništvu, djelomično smo odškrinuli vrata demografske zbilje ovoga područja s krajnje periferije Osmanskoga Carstva na prijelazu iz 18. u 19. stoljeće. Komparativno-historijski pristup je pokazao da se obilježja nataliteta uklapaju u pravilnosti utvrđene istraživanjima na raznim, zemljopisno bližim, ali i udaljenijim područjima. Slično je pokazala i analiza antroponimijskoga korpusa. Istraživanje podataka matičnih knjiga pružilo nam je prvi, preliminarni uvid u demografsku sliku dijela Ljubuškoga, a nadamo se da će nastavak istraživanja cjelokupne ljubuške mikrocjeline, značajno upotpuniti sliku i bar djelomično rekonstituirati njezin cjelokupni demografski razvoj.This study examines demographic trends within the micro unit Veljaci in the municipality of Ljubuški. The sources of primary data were the oldest registers of births from the turn of the 19th century in the area encompassed in the parish Veljaci. The data were analysed using historical and demographic, microhistorical and comparative-historical methodological approach. The research goalis to present former demographic reality of this micro-space at the empire border describe its demographic indicators and their dynamics, especially those related to the birth rate, and pinpoint any trends that would indicate demographic trends of the surrounding area, that is, former parish Ljubuški as a whole. With limited research and analysis of data collected in heuristic procedures for a broader and more comprehensive study of Ljubuški population, we gained an insight into demographic reality of this area from the extreme periphery of the Ottoman Empire at the turn of the 19th century. Comparative-historical approach showed that the characteristics fit into the regularity established by various studies, of geographically closer, but also more remote areas. The analysis of the anthrophonymy corpus also proved similar facts. The analysis of the data from parish registers provided the first, preliminary insight into the demographic image of one section of Ljubuški, and we hope that further research of the entire micro-unit of Ljubuški will significantly complement it and at least partially reconstruct its entire demographic development

Effects of Radiofrequency Electromagnetic Fields on Mammalian Spermatogenesis

Prema podacima dostupnima javnosti, smatra se da je u Hrvatskoj broj aktivnih mobilnih linija dosegao broj od oko 4 milijuna, dok se u cijelome svijetu taj broj penje na vrtoglave 2 milijarde. Zbog toga se postavlja pitanje djelovanja radiofrekvencijskog (RF) zračenja na zdravlje čovjeka, posebno na reprodukcijsko zdravlje i eventualne posljedice na zdravlje budućeg potomstva. Svrha ovog članka je pregled dosadašnjih istraživanja utjecaja RF zračenja mobilnih telefona na muški reprodukcijski sustav. Neka istraživanja provedena u uvjetima in vivo i in vitro pokazala su da RF zračenje može utjecati na stanicu i pojedine stanične dijelove. Dio istraživanja je pokazao da RF zračenje može utjecati na reprodukcijski sustav sisavaca i na stanice spermatogeneze. Budući da je spermatogeneza u normalnim fiziološkim uvjetima uravnotežen proces diobe, sazrijevanja i pohrane stanica, podložan je i osjetljiv na vanjske podražaje. Posebno osjetljive strukture u stanici su proteini koji čine stanični kostur, odnosno citoskelet. Citoskelet je strukturalni i funkcionalni dio stanice koji, izme|u ostaloga, ima važnu ulogu u pokretanju spermija te sudjeluje u morfološkim i funkcionalnim promjenama stanica tijekom spermatogeneze.This article reviews studies about the effects of radiofrequency electromagnetic (RF EM) fields on male reproductive system and reproductive health in mammals. According to current data, there are almost 4 million active mobile phone lines in Croatia while this number has risen to 2 billion in the world. Increased use of mobile technology raises scientific and public concern about possible hazardous effects of RF fields on human health. The effects of radiofrequencies on reproductive health and consequences for the offspring are still mainly unknown. A number of in vivo and in vitro studies indicated that RF fields could interact with charged intracellular macromolecular structures. Results of several laboratory studies on animal models showed how the RF fields could affect the mammalian reproductive system and sperm cells. Inasmuch as, in normal physiological conditions spermatogenesis is a balanced process of division, maturation and storage of cells, it is particularly vulnerable to the chemical and physical environmental stimuli. Especially sensitive could be the cytoskeleton, composed of charged proteins; actin, intermedial filaments and microtubules. Cytoskeleton is a functional and structural part of the cell that has important role in the sperm motility, and is actively involved in the morphologic changes that occur during mammalian spermiogenesis

Video head impulse test can detect brainstem dysfunction in multiple sclerosis

BACKGROUND: The aim of this study was to investigate the potential role of video head impulse test (vHIT) in the detection of brainstem lesions in patients with multiple sclerosis (MS). ----- METHODS: Sixty-eight participants were enrolled and divided into two groups: 39 healthy subjects (HC) (78 ears, 20 females, mean age 25,3±6,3) and 29 MS patients (58 ears, 14 females, mean age 33,7±7,7). Both groups underwent vHIT, and in MS group MRI was analyzed for the presence of brainstem lesions. vHIT pathology was defined as presence of overt saccades (<200ms) or lateral gain lower than 0.8 for lateral canal, and presence of overt saccades (<200ms) or posterior/anterior slope lower than 0.7. ----- RESULTS: In HC, decreased gain on horizontal canals was found in 8 out of 78 ears (11%), while 16 out of 58 ears (38%) had pathological results in the MS group. Mean gain of the lateral canals (60ms) was significantly reduced in MS group compared to HC (0.874±0143 vs. 0.954±0,170, p=0.004, respectively). Compared to HC overt saccades 200ms in lateral (p<0.001), anterior (p=0.019) and posterior canals (p=0.009), and covert saccades in the anterior (p=0.042) and posterior canals (p=0.046) were more frequent in the MS group. There was statistically significant association between the presence of BS MR lesions and bilateral pathology on vHIT for lateral semicircular canal (χ(1)=3.982, p=0.046). ----- CONCLUSION: These results indicate that vHIT can detect brainstem dysfunction in patients with MS