<p>Sposobnost insekata da se prilagode različitim ekolo&scaron;kim uslovima je veoma dobro<br />dokumentovana; oni predstavljaju najrasprostranjeniju grupu životinja na planeti, sa vrstama koje naseljavaju različita kopnena i vodena stani&scaron;ta, od tropskih predela do polova. Razumevanje mehanizama koji omogućavaju insektima da prežive ekstremne temperature i zadrže vitalne funkcije tokom dugog perioda dormancije je kao model sistem od interesa za mnoge naučne oblasti. Na osnovu načina na koji preživljavaju temperature ispod 0&ordm;C insekte možemo podeliti u tri grupe:<em> i)</em> insekti koji toleri&scaron;u formiranje leda u ekstraćelijskom prostoru,<em>ii)</em> insekti koji ne toleri&scaron;u zamrzavanje i moraju da ga izbegnu,&nbsp; a to&nbsp; čine superhlađenjem svojih telesnih tečnosti i<em>&nbsp; iii) </em>insekti koji preživljavaju zahvaljujući gubitku vode kroz permeabilnu kutikulu, &scaron;to je nazvano krioprotektivna dehidratacija. Zajednička odlika organizama sa različitim mehanizmima adaptacije na niske temperature je setbiohemijskih jedinjenja&nbsp; čija se fiziolo&scaron;ka funkcija razlikuje u zavisnosti da li organizam pripada grupi koja toleri&scaron;e ili ne toleri&scaron;e zamrzavanje. To su nukleatori kristalizacije leda, krio/anhidroprotektanti i antifriz proteini.<br />Cilj ovih istraživanja je bio ispitivanje molekularne osnove otpornosti na niske temperature dve vrste polarnih kolembola&nbsp;<em> Onychiurus arcticus </em>i <em>Cryptopygus</em> <em>antarcticus </em>kombinujući fiziolo&scaron;ki, biohemijski i molekularno biolo&scaron;ki pristup. Ispitivane vrste izbegavaju zamrzavanje svojih telesnih tečnosti primenjujući različite strategije preživljavanja. Za antarktičku vrstu&nbsp;<em> C. antarcticus </em>karakteristična je brza promena tačke superhlađenja, kao i njena bimodalna distribucija tokom leta, kada neke jedinke mrznu na&nbsp; vi&scaron;im temperaturama (manje otporne na hladnoću), a druga na nižim (otpornije na hladnoću). Ova bimodalna distribucija tačke superhlađenja je dobro dokumentovana, ali slabo razja&scaron;njena na molekularnom nivou. Druga, arktička vrsta<em>&nbsp; O. arcticus&nbsp;</em> koristi strategiju preživljavanja zimskih temperature koje idu i do -25&ordm;C nazvanu krioprotektivna dehidratacija. Na ovaj način, količina slobodne vode u telu se značajno redukuje, a akumulira se trehaloza koja deluje kao&nbsp; krio/anhidroprotektant. Iako je krioprotektivna dehidratacija opisana i kod drugih vrsta<br />insekata, molekularni mehanizmi koji se nalaze u osnovi ovog fenomena su veoma slabo razja&scaron;njeni.<br />Za karakterizaciju genoma generisano je 16379 EST sekvenci za&nbsp;<em> O. arcticus </em>i 1180 za&nbsp; <em>C. antarcticus</em>. To su ujedno i prvi javno dostupni podaci u bazama podataka o genomima ove dve vrste koji predstavljaju značajnu osnovu za komparativne genomske analize. Činjenica da kod obe analizirane vrste, oko 60% EST sekvenci nije pokazalo statistički značajnu sličnost sa proteinima iz baza podataka ukazuje na specifičan patern genske ekspresije kao adaptivni odgovor ispitivanih vrsta na niske temperature.<br />Sa ciljem da se identifikuju geni uključeni u preživljavanje niskih temperatura konstruisani su mikroereji, za&nbsp;<em> O. arcticus</em> &scaron;tampanjem 6912 cDNK u duplikatu, a za&nbsp; <em>C. antarcticus</em> &scaron;tampanjem 672 cDNK u duplikatu.. Analizom sekvenci identifikovanih putem homologije sa dostupnm bazama podataka kod C. antarcticusuočen je jasan trend povećane ekspresije gena koji kodiraju strukturne proteine u grupi koja je otporna na hladnoću. Ove strukturne proteine uglavnom&nbsp; čine kutikularni proteini, &scaron;to je u skladu sa rezultatima nedavnih istraživanja kod kolembola, da je presvlačenje proces tokom kog se snižava tačka superhlađenja, odnosno da varijacije u tački superhlađenja mogu nastati kao posledica endogenih fiziolo&scaron;kih procesa tokom presvlačenja. Kod&nbsp;<em> O. arcticus </em>analizom EST sekvenci i mikroereja identifikovani su<br />potencijalni geni i biohemijski putevi povezani sa krioprotektivnom dehidratacijom, a istakli bi gene uključene u metabolizam ugljenih hidrata, gene za akvaporine, proteine toplotnog stresa, LEA proteine i enzime antioksidativne za&scaron;tite.</p> / <p>The ability of insects to adapt to diverse ecological conditions iswell documented; they &nbsp;are the most diverse fauna on earth, with different species occupying arange of terrestrial and aquatic habitats from the tropics to the poles. Understanding the mechanisms by which insects survive such extreme temperatures and retain viability for longperiods in the dormant state is of great interest to many scientific fields. Insects have evolved three main strategies to survive sub-zero temperatures:&nbsp; i) freeze tolerance,&nbsp; ii) freeze avoidance and&nbsp; iii) cryoprotective dehydration. The main biochemical compounds involved in surviving sub-zero temperatures are same for different strategies but their physiological&nbsp; role is different. They include: ice nucleating agents (INAs), cryo/ anhydroprotectants, and antifreeze proteins (AFPs).&nbsp;</p><p>The aim of this study was to determine molecular adaptations to extreme cold&nbsp; environments, combining physiology, biochemistry and molecular biology&nbsp; pproaches, in thePolar Collembola:&nbsp; Cryptopygus antarcticus and&nbsp; Onychiurus arcticus. Both species are freeze avoiding but employ different strategies for surviving low temperatures. The Antarctic springtail&nbsp; C. antarcticusis capable of rapid cold hardening with a bi-modal distribution of super cooling points (SCP) with high (less cold-hardened) and low (more&nbsp; cold-hardened) groups of animals present even during the growing season in summer. This bimodal distribution has been well documented, but is poorly understood. The Arctic springtail&nbsp; O. arcticusemploys the strategy known as cryoprotective dehydration to survive winter temperatures as low as &nbsp; -25&ordm;C. With this technique, the amount ofavailable water in the body&nbsp; is reduced to almost zero and also there is an accumulation of trehalose, which acts as a cryo/anhydroprotectant. Although cryoprotective dehydration has been described in &nbsp;other&nbsp; insects, the molecular mechanisms behind this phenomenon are poorly understood.</p><p>A total of 16,379 EST clones were generated for O. arcticus and 1180 for C. antarcticus. This represents the first publicly available sequence data for this two species providing useful data for comparative genomic analysis. The fact that around 60% of the clones for both species showed no sequence similarity to annotated genes &nbsp;in the datasets, suggests a specific pattern of gene expression in these species as adaptation to low temperatures.</p><p>Two microarrays were constructed to identify genes involved in&nbsp; surviving low temperatures, one for C. antarcticus by printing 672 clones in duplicate and the other&nbsp; for O. arcticus by&nbsp; printing 6912 clones in duplicate. An analysis of those where putative function could be inferred via database homology, in C. antarcticus there was aclear pattern of up-regulation of structural proteins being associated with the cold tolerant group.&nbsp; These structural proteins mainly comprised cuticle proteins and provide support for the recenttheory that summer SCP variation within Collembola species could be a consequence of moulting, with moulting population having lowered SCPs. In O. arcticus EST and microarrayanalysis revealed clones&nbsp;and biochemical pathways associated with cryoprotective dehydration with a particular&nbsp; reference to genes involved in carbohydrate metabolism, aquaporin&nbsp; genes, heat shock&nbsp; proteins, LEA proteins and antioxidant enzymes.</p>

<p>Cilj istraživanja doktorske disertacije je bio ispitivanje mogućnosti primene<br />vlakana od nerđajućeg čelika za koalescenciju kapi mineralnih ulja različite polarnosti<br />pri različitoj permeabilnosti sloja. Pored toga cilj je bio i komparativna analiza efikasnosti separacije ispitivanih ulja vlaknima visoke i niske energije povr&scaron;ine. Postavljena je i modifikovana metoda kinetike upijanja tečnosti za ocenu sklonosti ulja ka odabranim vlaknima od kojih se formira sloj. Po prvi put je primenjena i metoda ve&scaron;tačkih neuronskih mreža za simulaciju koalescentne filtracije.<br />Eksperimentalni program koalescentne filtracije je realizovan na model emulziji<br />dispergovanog ulja u vodi konstantne ulazne koncentracije 500 mg/l,<br />pri konstantnoj temperaturi od 20&deg;C, horizontalnoj orijentaciji toka fluida i<br />prosečnoj veličini kapi ulja od 10 &mu;m. Uticaj geometrije sloja ispitivan je variranjem<br />permeabilnosti u opsegu od 0,1810^-9 m2 do 5,510^-9 m² za konstantnu<br />debljinu sloja od 5 cm. Testirana su tri uzorka mineralnog ulja velikog raspona<br />viskoznosti i polarnosti. Svi ogledi su realizovani pri konstantnoj brzini fluida u intervalu od 10 m/h do 80 m/h. Izlazna koncentracija dispergovane faze<br />odredivana je FTIR spektrofotometrijom.<br />Značajan doprinos u istraživanju fenomena koalescencije u sloju vlakana<br />ogleda se u utvrdivanju mogućnosti primene vlakana nerdajućeg čelika na<br />separaciju kapi mineralnih ulja, razumevanju simultanog uticaja energije<br />povr&scaron;ine, geometrije sloja i prirode uljne faze, kao i uvodenju nove veličine<br />izo-izlazne koncentracije. Test odredivanja kinetike upijanja tečnosti je pokazao<br />da odnos liofilno-liofobne kva&scaron;ljivosti materijala adekvatno opisuje sklonost<br />nekog filtarskog materijala ka separaciji ulja mineralnog porekla. Ovako<br />sveobuhvatna analiza uticaja različitih parametara na efikasnost koalescentne<br />filtracije, data u ovoj disertaciji, nije zabeležena u dostupnim literaturnim navodima.<br />Rezultati doktorske disertacije omogući će skraćivanje vremena i materijalnih<br />tro&scaron;kova neophodnih za projektovanje koalescera, jer smanjuju potreban<br />obim eksperimentalnih istraživanja potrebnih za uspe&scaron;no projektovanje.<br />Odabrani uslovi rada, prvenstveno prečnik vlakana materijala u odnosu na<br />ulaznu veličinu kapi, kao i način njihovog pakovanja, uz obezbedivanje poznate<br />i definisane permeabilnosti, obezbedili su željenu separaciju, čija se efikasnost<br />separacije kapi ispitivanih ulja vlaknima od nerdajućeg čelika kreće u<br />opsegu od 91% do 99% za opseg brzina fluida od 10 m/h do 50 m/h. Kod sloja<br />vlakana od nerdajućeg čelika efikasnija separacija je zapažena pri niskim vrednostima<br />permeabilnosti, dok je kod polimernog materijala obrnut slučaj. Zaključeno je da, u postojećim okolnostima, kod posmatranih materijala dominiraju<br />različiti mehanizmi koalescencije u sloju. Oblik zavisnosti izlazne koncentracije<br />od brzine i permeabilnosti za oba ispitivana materijala, nerdajući čelik i<br />polipropilen, je sličan. Polipropilen ima veći radni opseg brzina u odnosu na<br />nerdajući čelik. Medutim, nerdajući čelik uspe&scaron;nije separi&scaron;e ulje najniže viskoznosti<br />u oblasti niskih vrednosti permeabilnosti i pri niskim radnim brzinama<br />u odnosu na polipropilen. Zadovoljavajući kvalitet separacije se kod polipropilena<br />ostvaruje pri najvi&scaron;oj permeabilnosti i u &scaron;irokom opsegu brzina, dok se<br />kod nerđajućeg čelika najvi&scaron;e vrednosti kritične brzine za ceo opseg ispitivane<br />viskoznosti ostvaruju pri najnižoj permeabilnosti sloja.</p> / <p>The aim of the doctoral thesis was to investigate the possibility of the stainless<br />steel fibers application for the coalescence of mineral oil drops with different<br />polarity varying also the bed permeability. Additional aim was the comparative<br />analysis of the tested oil separation efficiency with fibers that have high<br />and low surface energy. The method for the evaluation of the fiber-liquid wetting<br />kinetic was set up and modified in order to assess the affinity of oil to the<br />selected fiber that was used to form the filtration bed. For the first time, the<br />method of artificial neural networks was applied to simulate the coalescence<br />filtration.<br />Experimental program of coalescence filtration was performed on oil-in-water<br />model emulsion with constant inlet concentration of 500 mg/l, at a constant<br />temperature of 20&deg;C, horizontal fluid flow orientation and average oil drop<br />size of 10 &mu;m. The influence of bed geometry was studied varying bed permeability<br />in the range from 0,1810^-9 m2 to 5,51010^-9 m2 for the constant layer thickness of 5 cm. Three samples of mineral oil that have large range of viscosity<br />and polarity were tested. All experiments were carried out at constant<br />fluid velocity in the range from 10 m/h to 80 m/h. The output dispersed phase<br />concentration was determined by FTIR spectrophotometry.<br />A significant contribution to the research of the coalescence phenomenon in<br />a fiber bed was achieved by determining the possibility to use stainless steel<br />fibers for the separation of mineral oil drops, broadening the apprehension<br />of the simultaneous influence of surface energy, bed geometry and oil phase<br />nature, as well as the introduction of an iso-output concentration as a new<br />parameter. The evaluation of the fiber-liquid wetting kinetic showed that the<br />lipophilic-lyophobic wettability ratio of the material adequately describes the<br />tendency of a filter material for the mineral oil separation. Such comprehensive<br />analysis of the various parameters impact on the efficiency of coalescence<br />filtration, presented in this thesis, was not found in available literature. The results<br />of the doctoral thesis will enable the reduction of time and material cost<br />needed for the design of coalescer, by decreasing the extent of experimental<br />research necessary for successful design.<br />Selected working conditions, primarily the fiber diameter in relation to the input<br />drop size, as well as bed packaging, while ensuring the known and defined<br />bed permeability, provided the desired separation, with the oil drop separation<br />efficiency of tested stainless steel fibers in the range from 91% to 99% for a fluid<br />velocity range from 10 m/h to 50 m/h. When stainless steel was used, more<br />efficient separation was observed for the low bed permeability, whereas for<br />the polymer fibers the reverse order was identified. It was concluded that, in<br />the existing circumstances, different mechanisms of oil drop coalescence dominate<br />for these materials. The dependence of output concentration from the<br />velocity and bed permeability for both tested materials, stainless steel and polypropylene, was similar. Polypropylene has a higher operating velocity range<br />in comparison to stainless steel. However, when compared to polypropylene,<br />stainless steel separates more successfully the oil with the lowest viscosity in<br />the low bed permeability and at low fluid velocity domain. Satisfactory quality<br />of separation with polypropylene is achieved at the highest bed permeability<br />and in a wide fluid velocity range, whereas, with the stainless steel, the highest<br />values of critical velocity, for the entire range of tested viscosity, are realized at<br />the lowest bed permeability.</p>

<p>Uvod: Bronhopulmonalna displazija (BPD) je najče&scaron;ća i najteža respiratorna posledica prematuriteta. Utvrđivanje najznačajnijih faktora rizika za nastanak BPD kod novorođenčadi porođajne mase (PM) ispod 1500g može omogućiti procenu rizika za&nbsp; nastanak bolesti i identifikaciju novorođenčadi u visokom riziku, &scaron;to je važno za pružanje informacija roditeljima o prognozi,&nbsp; planiranje preventivnih i terapijskih mera i stratifikovanje novorođenčadi koja su u riziku za sprovođenje budućih istraživanja. Cilj: Utvrđivanje incidencije, stepena težine BPD, smrtnosti, identifikacija najznačajnijih prenatalnih i postnatalnih faktora rizika za nastanak BPD, konstrukcije modela predikcije za nastanak BPD. Materijal i metode: Istraživanje je sprovedeno na 504&nbsp; prevremeno rođene novorođenčadi PM&lt;1500g koja su rođena u porodili&scaron;tima u AP Vojvodini i lečena u tercijarnom Centru za neonatologiju i intenzivnu negu i terapiju, na Institutu za zdravstvenu za&scaron;titu dece i omladine Vojvodine u periodu od&nbsp; 2006.-2011. godine. Retrospektivno je analizirano prisustvo BPD, prema stepenima težine, smrtnost. Podaci su izdvojeni iz&nbsp; istorija bolesti za svako novorođenče, 30 potencijalnih prenatalnih i postnatalnih faktora je opisano deskriptivnom i univarijantnom statistikom. Statstički najznačajniji faktori su uneti u multifaktorsku logističku regresionu analizu u cilju&nbsp; konstrukcije prediktivnih modela za nastanak BPD u 1.,14. i 21. danu neonatalnog života. Podaci su obrađeni u StatSoft-ovom&nbsp; programskom paketu Statistica 10.0.&nbsp; Validacija modela predikcije je sprovedena u prospektivnom delu istraživanja, na 100&nbsp;&nbsp;&nbsp; prevremeno rođene novorođenčadi&lt;1500g, u periodu od 2012-2013. godine. Rezultati: U retrospektivnom delu&nbsp; istraživanja,&nbsp; od 504&nbsp; novorođenčeta PM&lt;1500 grama, umrlo je 17.65%, BPD je imalo 45.43% (blagu BPD 19.44%, srednje te&scaron;ku 19.84%,&nbsp; te&scaron;ku&nbsp; 6.15%), srednje te&scaron;ku i&nbsp; te&scaron;ku 25.99%.Antenatalna primena kortikosteroida je zastupljena u 47.02%, surfaktant&nbsp;&nbsp; je&nbsp;&nbsp; primenjen kod 69.78% novorođenčadi. Najznačajniji prenatalni prediktivni faktor rizika za nastanak BPD/smrtnog ishoda je horioamnionitis (OR 5.72; 95% CI 3.42-9.62), dok su protektivni faktori: prenatalna primene kortikosteroida (OR&nbsp; 0.41;&nbsp; 95%CI&nbsp; 0.29-0.60), porođaj carskim rezom (OR&nbsp; 0.24; 95% CI 0.16-0.36). Najznačajniji&nbsp; postnatalni prediktivni faktori rizika su: GS&nbsp; (p&asymp;0.00), PM (p&asymp;0.00), reanimacija u porođajnoj sali (OR 7.01; 95% CI 4.12-12.01), rana&nbsp; neonatalna&nbsp; sepsa&nbsp; (OR&nbsp; 7.35;&nbsp; 95%CI&nbsp; 3.79-14.58), RDS&nbsp; (p&asymp;0.00), primena surfaktanta (OR13,3;95%CI 8,2 - 21,67), DAP (OR 4.12; 95%CI&nbsp; 2.47-6.89),&nbsp; dok&nbsp; je&nbsp; ženski&nbsp; pol&nbsp; protektivan (OR&nbsp; 0.61; 95% CI 0.42-0.89). FiO2 i IPPV su u svim posmatranim danima značajni faktori rizika. Primena IPPV u 1. danu (OR 10.71;&nbsp; 95% CI 6.67-17.26); u ostalim danima rizik od BPD raste prema rastućoj invazivnosti respiratorne&nbsp; potpore.&nbsp; Konstruisani su modeli&nbsp; predikcije za 1, 14 i 21. dan života, modeli imaju visoku prediktivnu vrednost: ukupan procenat uspe&scaron;nosti&nbsp; modela je 84.26%-90.80%, modeli sa ne&scaron;to većim uspehom predviđaju&nbsp;&nbsp; prisustvo (85.36%-94.12%), nego odusustvo BPD (81.72-86.56%). OR modela je 28.07-103.04. Modeli su uspe&scaron;no validirani&nbsp; na 102 pacijenta sa ukupnim procentom uspe&scaron;nosti (82-90%), PPV (0.86-0.94) i NPV (0.76-0.87). Zaključak:&nbsp; Kori&scaron;ćenjem&nbsp; prenatalnih i postnatalnih kliničkih podataka moguće je predvideti nastanak BPD ili smrtnog ishoda.</p> / <p>Introduction: Bronchopulmonary dysplasia (BPD) is the most common serious pulmonary morbidity in very low birth weight (VLBW) infants. It is of clinical importance to determine clinical variables that are associated with BPD in order to identify infants who are at risk of developing BPD; it contributes to BPD prevention, may enable prognostic information for parents and future studies design. Objective: The aim of this study was to determine the incidence and severity of BPD, mortality rate in VLBW infants, to identify prenatal and postnatal predictive risk factors for bronchopulmonary dysplasia and competing outcome of death and to develop predictive models. Materials and Methods: Study was conducted in 504 VLBW infants born in the maternity hospitals in Vojvodina and admitted to tertiary Center for newborn and neonatal intensive care at the Institute for Child and Youth Health Care of Vojvodina, from January 2006. to December 2011. Data were retrospectively collected from clinical records for outcomes BPD or death; prenatal and postnatal factors associated with BPD were collected at three postnatal ages and examined by descriptive and univariate statistics; factors that were significantly associated with BPD and/or death were entered into a multivariate logistic regression analysis for develop predictive models. Data were analyzed using StatSoft&#39;s software package Statistica 10.0. Validation of the models were conducted in a prospective study in 102 VLBW infants born from January 2012. to December 2013. Results: There were 504 very low birth weight infants who were eligible for this study, 17.65% died, 45.43% developed BPD (mild BPD 19.44%, moderate 19.84%, severe 6.15%), moderate and severe 25.99%. The mean birth weight for the cohort was 1125.6&plusmn;280.9g, the mean gestation age was GS 28,78&plusmn;3,01, 49.21% were male. Surfactant received 69.78%, antenatal steroids 47.02% newborns. Key risk factors for BPD and/or death were: chorioamnionitis and maternal infections at delivery (OR 5.72; 95% CI 3.42-9.62); protective prenatal factors were: antenatal corticosteroid therapy (OR 0.41; 95%CI 0.29-0.60), cesarean delivery (OR 0.24; 95% CI 0.16-0.36). Postnatal rick factors were: GS (p&asymp;0.00), birth weight (p&asymp;0.00), delivery room resuscitation (OR 7.01; 95% CI 4.12-12.01), early neonatal sepsis (OR 7.35; 95%CI 3.79-14.58), RDS (p&asymp;0.00), surfactant (OR13,3;95%CI 8,2 - 21,67), DAP (OR4.12; 95% CI 2.47-6.89), while female gender was protective (OR 0.61; 95% CI 0.42-0.89). At each time point studied, FiO2 was significantly higher in BPD/death, as well as respiratory support; on the first day invasive respiratory support was significantly associated with BPD/death (IPPV and HFOV) (OR 10.71; 95% CI 6.67-17.26), in other days BPD was associated with increasing invasiveness of respiratory support. In multifactorial logistic regression analysis separately predictive models were developed at three postnatal ages, at 1st, 14th and 21st day. Models had high predictive performance: total success of the models were 84.26% - 90.80%, models successfully predicted the presence of BPD in 85.36% -94.12%, absence of the BPD in 81.72 - 86.56% cases. OR of models were 28.07-103.04. The models were successfully validated on 102 patients with a total percentage of success 82 - 90%, with PPV 0.86-0.94 and NPV 0.76-0.87. Conclusion: Using prenatal and postnatal clinical data it is possible to predict the development of BPD and/or death in very low birth weight infants. It is very important to identify risk factors for BPD development in order to decrease the incidence of BPD and mortality rate.</p>