Meron ground states of quantum Hall droplets

We argue that topological meron excitations, which are in a strong coupling phase (bound in pairs) in infinite quantum Hall ferromagnets, become deconfined in finite size quantum Hall systems. Although effectively for larger systems meron energy grows with the size of the system, when gyromagnetic ratio is small meron becomes the lowest lying state of a quantum Hall droplet. This comes as a consequence of the many-body correlations built in the meron construction that minimize the interaction energy. We demonstrate this by using mean field ansatzes for meron wave function. The ansatzes will enable us to consider much larger system sizes than in the previous work [A. Petkovic and M.V. Milovanovic, PRL 98, 066808 (2007)], where fractionalization into merons was introduced.Comment: 6 pages, 6 figure

Procena koeficijenta heritabiliteta za broj živorođene prasadi u prva tri prašenja krmača švedskog landrasa

The main objective of this study was to evaluate phenotypic and genetic variation of the number of piglets born alive (NBA) Swedish Landrace sows (SL) in three consecutive parities under the influence of sires, year and season of mating. The study included: 618 litters in the first, 470 in the second and 403 litter in the third farrowing. Testing the homogeneity of variance was performed with Levene's test. The data were analyzed using analysis of variance (Statistica Ver. 6.0., 2003). Heritability coefficients were evaluated by intra-class correlation. Swedish Landrace sires have influenced on the variability of the NBA's daughter in the first and second farrowing (p (lt) 0.05), but not in the third farrowing. Year and season of mating was not influenced on the variability of the NBA (p>0.05). The estimated heritability coefficients for the NBA were the highest in the second (0.123), then the first (0.092) and lowest in the third farrowing (0.030).Osnovni cilj rada bio je da se oceni fenotipska i genetska varijabilnost broja živorođene prasadi (NBA) krmača švedskog landrasa (SL) u tri uzastopna prašenja pod uticajem očeva, godine i sezone pripusta. Istraživanjem je bilo obuhvaćeno: 618 legala u prvom, 470 u drugom i 403 legla u trećem prašenju. Testiranje homogenosti varijanse izvršeno je testom Levene-a. Dobijeni podaci su obrađeni metodom analize varijanse (Statistica Ver. 6.0., 2003). Koeficijenti heritabiliteta su ocenjeni metodom intra-klasne korelacije. Očevi švedskog landrasa uticali su na varijabilnost NBA kćeri u prvom i drugom prašenju (p (lt) 0.05), ali ne i u trećem prašenju. Godina i sezona pripusta nisu uticale na varijabilnost NBA (p>0.05). Procenjeni koeficijenti heritabiliteta za NBA su bili najviši u drugom (0.123), zatim u prvom (0.092) i najniži u trećem prašenju (0.030)

Bistability in superconducting rings containing an inhomogeneous Josephson junction

We investigate the magnetic response of a superconducting Nb ring containing a ferromagnetic PdNi Josephson junction and a tunnel junction in parallel. A doubling of the switching frequency is observed within certain intervals of the external magnetic field. Assuming sinusoidal current-phase relations of both junctions our model of a dc-SQUID embedded within a superconducting ring explains this feature by a sequence of current reversals in the ferromagnetic section of the junction in these field intervals. The switching anomalies are induced by the coupling between the magnetic fluxes in the two superconducting loops.Comment: 5 pages, 4 figure

Subwavelength hole arrays with nanoapertures fabricated by scanning probe nanolithography

Owing to their surface plasmon-based operation, arrays of subwavelength holes show extraordinary electromagnetic transmission and intense field localizations of several orders of magnitude. Thus they were proposed as the basic building blocks for a number of applications utilizing the enhancement of nonlinear optical effects. We designed and simulated nanometer-sized subwavelength holes using an analytical approach. In our experiments we used the scanning probe method for nanolithographic fabrication of subwavelength hole arrays in silver layers sputtered on a positive photoresist substrate. We fabricated ordered nanohole patterns with different shapes, dispositions and proportions. The smallest width was about 60 nm. We characterized the fabricated samples by atomic force microscopy

Fenotipska varijabilnost osobina plodnosti čistorasnih krmača u prva tri prašenja

Investigation of the phenotypic variability of fertility traits was performed on Swedish Landrace sows (926 sows) deriving from single herd in Serbia. Data was processed by method of least squares (Harvey, 1990), and following fixed factors were included into the model: sire, season, litter genotype and order of farrowing, as well as regression effect of age at first farrowing, duration of lactation and number of reared (raised) piglets per litter. Traits of litter size varied (P lt 0.01) under the influence of sire and order of parities (first two parities). Number of still born as well as reared piglets per litter depended on the litter genotype (P lt 0.01). Year and season had no effect on variation of litter size traits except LWW (first two and three parities). Age of sows at first farrowing demonstrated linear effect (P lt 0.01) on size of their litter at farrowing (first three parities). Litter size and weight at weaning were under regression effect of lactation duration as well as corrected litter size (CLS) or number of weaned piglets (NW).Ispitivanje fenotipske varijabilnosti osobina plodnosti krmača rase švedski landras sprovedeno je u jednom zapatu svinja u Srbiji. Podaci su analizirani primenom različitih modela metoda najmanjih kvadrata (Harvey, 1990), u koje su bili uključeni sledeći fiksni uticaji: otac, godina, sezona, genotip legla i redosled prašenja, kao i regresijski uticaji uzrasta pri prvom prašenju, trajanja laktacije i broja gajene prasadi u leglu. Istraživanjem je bilo obuhvaćeno 926 krmača i njihova 926 prva, 1598 prva dva i 2115 prva tri prašenja. Prosečna ispoljenost trajanja perioda od zalučenja do estrusa i oplodnje (W-E i W-C), broja živorođene (NBA), ukupnorođene (TNB), mrtvoroĐene (NSB) i odgajene prasadi (NW) kao i mase legla pri zalučenju (LWW) u prvom, prva dva i prva tri prašenja je bila: 9.77, 8.51, 7.80; 23.77, 20.98, 19.49; 8.31, 8.91, 9.19; 8.87, 9.46, 9.78; 0.56, 0.54, 0.51; 7.57, 8.04, 8.24 i 52.43, 58.18, 61.10, respektivno. Osobine veličine legla su varirale (P lt 0.01) pod uticajem oca i redosleda prašenja (prva dva prašenja). Broj mrtvorođene kao i odgajene prasadi u leglu zavisili su od genotipa legla (P lt 0.01). Godina i sezona nisu uticale na variranje osobina veličine legla osim na LWW (prva dva i tri prašenja). Uzrast krmača pri prvom prašenju ispoljio je linearan uticaj (P lt 0.01) na veličinu njihovih legala pri prašenju (prva tri prašenja). Veličina i masa legla pri zaluženju su bili pod regresijskim uticajem trajanja laktacije, korigovane veličine legla (CLS) ili broja odgajene prasadi (NW)

Fiksni deo modela za procenu priplodne vrednosti svinja na osnovu veličine legla

The goal of this paper was to investigate the effect of various fixed effects on the number of born alive piglets in litter (NBA), based on results of Swedish Landrace sow fertility on three farms in Serbia, in order to determine the best adapted model for assessing genetic parameters and breeding value. Analysis of phenotipic variability of the NBA of Swedish Landrace sows was carried out based on fertility results on three swine farms (A, B and C) in the Republic of Serbia. Data sets encompassed reproduction indicators for 2803 (A), 1826 (B) and 2235 (C) sows, i.e. their 11014, 6757 and 8452 litters, respectively. For this analysis was used fix model of least square method which includes fixed effects of farrowing number, season of conception shown as combination of year and month, litter genotype, duration of previous period from weaning to conception, effect of sow age at farrowing like quadratic regression nested within farrowing number and linear regression influence of duration of previous lactation. The average NBA was within the interval from 9.13 (A) to 9.76 piglets (B and C). The monitored trait statistically highly significantly (p lt 0.001) varied under the effect of all systematic factors encompassed by the applied model, regardless of the source of analyzed data, Only the linear regression effect of duration of previous lactation for farm B was assessed as having lower statistical significance (p lt 0.05).Cilj ovoga rada bio je da se ispita uticaj različitih sistematskih faktora na variranje broja živorođene prasadi u leglu (BŽP) radi određivanja najprilagođenijeg modela za ocenu genetskih parametara i procenu priplodne vrednosti krmača. Analiza fenotipske varijabilnosti BŽP u leglima krmača rase švedski landras sprovedena je na osnovu reproduktivnih pokazatelja 2803 (farma A), 1826 (farma B) i 2235 (farma C) krmača, odnosno njihovih 11014, 6757 i 8452 legala, respektivno. Korišćen je fiksni model metoda najmanjih kvadrata u koga su bili uključeni uticaj prašenja po redu, sezone uspešnog pripusta, genotipa legla, trajanja perioda zalučenje - oplodnja, kvadratni regresijski uticaj starosti krmače pri prašenju ugnježđen u okviru prašenja po redu i linearni regresijski uticaj trajanja prethodne laktacije. Prosečan BŽP se kretao u intervalu od 9.13 (A) do 9.76 (B i C). Svi determinisani uticaji obuhvaćeni modelom su ispoljili statistički vrlo visoko značajan uticaj (p lt 0.001) na variranje BŽP nezavisno od toga koji set podataka je bio analiziran, osim uticaja trajanja prethodne laktacije na farmi B koji je bio ocenjen kao statistički značajan (p lt 0.05)

Evaluation of aloe emodin effect on B16 and A375 melanoma cells and their sensitivity to anticancer drugs and immune response

Aloe emodin (AE) spada u biljne molekule antraciklinskog tipa koji zahvaljujući reaktivnim grupama na atomima ugljenika benzenovih prstenova pokazuje izrazitu reaktivnost i posledično široki spektar biološke aktivnosti poput baktericidnog, fungicidnog, viricidnog, imunosupresivnog, antiinflamatornog, hepatoprotektivnog, laksativnog i vazorelaksirajućeg delovanja. Istraživanja novijeg datuma stavljaju u žižu interesovanja njegova antitumorska dejstva. Ciljevi koji su postavljeni u ovoj tezi podrazumevali su utvrđivanje tumoricidnog delovanja AE-a na ćelije mišjeg, B16 i humanog, A375 melanoma koje se inicijalno razlikuju u redoks statusu i aktivnosti signalnih puteva uključenih u kancerogenezu. Uz uporednu analizu unutarćelijskog odgovora pomenutih linija na tretman AE-om, ispitivan je i uticaja AE-a na osetljivost melanoma na imunski odgovor usmeren protiv transformisane ćelije kao i na efikasnost konvencionalne citostatske terapije. AE je snažno inhibirao rast obe ćelijske linije posredstvom različitih mehanizama. U slučaju A375 ćelija, AE je doveo do indukcije apoptoze zavisne od aktivnosti kaspaza uz smanjenje nivoa antiapoptotskih proteina XIAP i Bcl-2. Suprotno, tretman AE-om je indukovao ireverzibilnu diferencijaciju B16 ćelija u smeru primarnog fenotipa manifestovanog povećanom ekspresijom enzima tirozinaze i naknadnom produkcijom melanina. Opisana promena B16 ćelija bila je praćena brzom akumulacijom p53, ciklina D1 i D3. Ključni događaj u diferencijaciji B16 ćelija je, najverovatnije, povećana produkcija H2O2 indukovana AE-om. U osnovi heterogenih ishoda tretmana istovetnim agensom je recipročna regulacija aktivnosti ERK1/2 i Akt. Poseban značaj ima podatak da se apoptoza pokrenuta AE-om u A375 ćelijama odvija u uslovima prekomerne aktivnosti Akt. Analiza paralelnog tretmana ćelija melanoma AE-om i konvencionalnim citostaticima (doksorubicin i paklitaksel) pokazala je da pomenuta supstanca umanjuje efikasnost hemioterapije. Nekonzistentnost ishoda ko-tretmana AE-a i medijatora imunskog odgovora iz familije TNF molekula ukazala je na kompleksnost uticaja mikrosredine na učinak AE-a. U celini, rezultati ove doktorske disertacije pokazuju kako specifičnost ćelija melanoma definiše mehanizam delovanja AE-a iako ne ugrožava njegov antitumorski potencijal. S druge strane, opisani rezultati upozoravaju na opasnost kombinovanja biljnih preparata sa konvencionalnim terapeuticima usled mogućeg neutrališućeg efekta.Aloe emodin is an herbal antraquinone that, due to reactive groups on the carbon atoms of benzene rings, posseses a strong reactivity and consequently shows a wide range of biological activities such as antibacterial, antifungal, antiviral, diuretic, immunosuppressive, anti-inflammatory, hepatoprotective, laxative and vasorelaxant. Recent studies put the focus on its antitumor effects. The aim of this thesis was to determine and evaluate antitumor activity of AE on two melanoma cell lines that initially differs in redox status and activities of signaling pathways involved in carcinogenesis: mouse melanoma B16, and human melanoma A375 cells. Together with comparative analysis of the intracellular responses of two lines to the AE treatment, the impact of AE on the sensitivity of melanoma to antitumor immune response as well as the efficiency of conventional cytostatic therapy, were examined. AE decreased the growth of both cell lines through different mechanisms. In the case of A375 cells, AE inducted caspase dependent apoptosis by reducing protein levels of antiapoptotic molecules XIAP and Bcl-2. In contrast, treatment with AE promoted irreversible differentiation of B16 cells towords its primary phenotype manifested through increased expression of the tyrosinase and the subsequent production of melanin. Described change in B16 cells was accompanied by a rapid accumulation of p53, cyclin D1 and D3. Increased production of H2O2 triggered by AE is probably first in a line of events responsible for induction of differentiation of B16 cells. Opposite regulation of two main signaling pathways involved in cell proliferation, differentiation and death- MEK-ERK1/2 and PI3K-Akt in tested cell lines could be essential for different outcome of the treatment with single agent. Furthermore, analysis of the parallel treatment of melanoma cells with the AE and conventional cytostatics (doxorubicin and paclitaxel) showed that introduced substance decreases the effectiveness of chemotherapy. Incoherent outcome of co-treatment of AE and TNF, FasL or TRAIL, the most relevant mediators of nonspecific immune response aginst tumor cells, points to the complexity of the influence of microenvironmental factors to the effect of AE. In general, the results of this PhD thesis show that cell specificity of melanomas defines the mechanism of AE action, while it does not jeopardize its anticancer potential. On the other hand, presented results point to a danger of combining herbal medicines with conventional therapeutics due to their possible neutralizing effects

Uticaj obima analiziranih podataka na tačnost selekcijskih indeksa za procenu priplodne vrednosti krmača

Objective of this paper was to establish to what extent the accuracy of constructed selection indices will be changed depending on the scope of analyzed data relating to fertility based on which parameters necessary for construction of selection indices (SI) were established. Fertility results of Swedish Landrace sows obtained on three farms in Republic of Serbia (farms 1, 2 and 3) were analyzed. Parameters necessary for construction of SI were determined by application of different mixed models of the method of Least Squares. For each farm three SI were constructed for evaluation of sow breeding value based on realized fertility in the way that parameters necessary for SI construction were calculated based on fertility results in the first (SI1), first two (SI2) and first three farrowings (SI3). Accuracy of constructed Sis varied within following limits - from low rIH = 0.255 (SI3 for Farm 2) to rIH = 0.405 (SI1 for Farm 3), and only in the case of SI2 for Farm 2 it was in the category of very low (rIH = 0.231). Introduction into analysis of fertility results realized in the second and third farrowing resulted in decrease of accuracy of constructed selection indices.U ovom radu rezultati istraživanja su pokazali da je tačnost selekcijskih indeksa konstruisanih na osnovu parametara ocenjenih analizom rezultata plodnosti (BŽP i BOP) ostvarenih na posmatranim farmama bila od rIH = 0.255 (SI3 za Farmu 2) do rIH = 0.405 (SI1 za Farmu 3), a samo je u slučaju SI2 za Farmu 2 bila u kategoriji jako slabe (rIH = 0.231). Povećanje obima analiziranih rezultata plodnosti dovelo je do smanjenja tačnosti SI

Acute kidney injury biomarkers after cardiac surgery in adult patients

Kardiohirurške operacije izvedene uz kardiopulmonalni by-pass (CPB) su drugi najčešći uzrok AOB, što je povezano sa porastom mortaliteta, morbiditeta i dužinom hospitalizacije. AOB udruženo sa kardiohirurškim procedurama (CSA-AKI) karakteriše naglo pogoršanje funkcije bubrega, koje nastaje pod uticajem raznih faktora kao što su: ishemijsko-reperfuziona oštećenja, metaboličke abnormalnosti, aktivacija neurohumoralnog odgovora, zapaljenski i oksidativni stres kao i egzogeni i endogeni toksini. Incidenca pojave CSA-AKI je između 8,9% i 39%. Cilj: Utvrđivanje incidence, značaja opštih karakteristika, specifičnih parametara vezanih za CPB, standardnih laboratorijskih, gasnih i analiza acidobaznog statusa, standardnih pokazatelja bubrežne funkcije i novih biomarkera bubrežnog oštećenja (KIM-1 i u-NGAL) u nastanku, ranom otkrivanju i predikciji akutnog oštećenja bubrega kod elektivnih kardiohirurških operacija. Bolesnici i metode: Ova prospektivna, opservaciona studija uključuje 100 odraslih niskorizičnih bolesnika za razvoj AOB, planiraih za izvođenje elektivnih kardiohirurških intervencija uz primenu CPB-a: aortokoronarnog by-passa, valvularne hirurgije i kombinovanih procedura (koronarna i valvularna hirurgija). Svim bolesnicima su preoperativno prikupljeni anamnestički podaci, obavljen je fizikalni pregled, izmereni hemodinamski parametri i zabeležena ejekciona frakcija (EF). Izvršena je klasifikacija bolesnika po NYHA protokolu i procenjen je operativni rizik za razvoj AOB primenom dva skora: Cleveland Clinic score (CCS) i Leicester Cardiac Surgery Research AKI Risk Score kalkulatora (LCSRARS)...Cardiac surgery procedures with cardiopulmonary by-pass (CPB) are the second most common cause of Acute Kidney Injury (AKI), which is connected with the increase of mortality, morbidity and the length of hospitalization. AKI associated with cardiovascular procedures (CSA-AKI) is characterized by rapid deterioration of kidney function, which is caused by various factors such as: ischemicreperfusion injury, metabolic abnormalities, activation of neurohumoral response, inflammatory and oxidative stress, as well as exogenous and endogenous toxins. The incidence of CSA-AKI is between 8.9% and 39%. Goal: Determination of incidence and the significance of general characteristics, specific parameters related to cardiopulmonary by-pass, standard laboratory, gas and acid-base status analysis, standard renal function indicators and novel biomarkers of kidney injury (KIM-1 and u-NGAL) in emergence, early detection and the prediction of acute kidney injury in elective cardiac surgery procedures. Patients and Methods: This prospective, observational study included 100 adult, low-risk patients for Acute Kidney Injury (AKI) development, planned for elective cardiac surgery with cardio pulmonary bypass (CPB): aortocoronary bypass surgery, heart valve surgery and combined procedures (coronary and heart valve surgery). All patients were preoperatively examined, anamnestic data were collected, physical examination performed, hemodynamic parameters measured and ejection fraction recorded. The classification of patients under the NYHA protocol was performed and the operational risk for the development of AKI was evaluated using two scores: Cleveland Clinic score (CCS) and Leicester Cardiac Surgery Research AKI Risk Score (LCSRARS). The blood and urine samples were taken the day before operation, shortly before or immediately after CPB, as well as 3h, 12h, 24h and 48h after the CPB was performed..

Self-healing hybrid nanocomposite materials

Fokus ove doktorske disertacije je na pripremi i karakterizaciji hibridnih nanokompozitnih materijala sa inkorporiranim staklenim kapilarama u kojima se nalaze agensi samozalečenja, kao i na procesiranju i karakterizaciji hibridnih nanokompozitnih materijala sa elektropredenim vlaknima poli(stiren)a (PS), u kojima se nalaze Grabsovi katalizatori prve i druge generacije zasebno. Netkani mat elektropredenih PS vlakna ima ulogu polimerna mreže – nosača katalizatora, čineći ga dostupnim u svim delovima kompozita. Elektropredena PS vlakna štite Grabsov katalizator od deaktivacije prouzrokovane dejstvom amina koji se koristi kao umreživač epoksidnog prekursora, reakcijom sa epoksidnim prekursorom i atmosferskim uslovima tokom procesiranja kompozitnog materijala. Ispitivan je uticaj koncentracije monomera i katalizatora na efikasnost samozalečenja. Takođe, s obzirom na to da su kompozitni materijali često izloženi različitim spoljašnjim uticajima, izvršena su ispitivanja uticaja promene temperature na efikasnost samozalečenja. Ispitivanje efikasnosti je vršeno poređenjem apsrobovanih energija pri udaru pre i posle zalečenja materijala. Sa ciljem identifikacije nastalog polimera kojim se materijal zalečuje, izvršene su različite analize, kao što su skenirajuća elektronska mikroskopija (FESEM), infracrvena spektroskopija sa Furijeovom transformacijom (FTIR) i termička degradacija. Navedene analize su pokazale da je sistem sa elektropredenim PS vlaknima u ulozi nosača Grabsovog katalizatora veoma uspešan i da nudi veliki potencijal na polju hibridnih nanokompozitnih materijala sa efektom samozalečenja. Na osnovu dosadašnjih saznanja, ova mogućnost nije bila predmet ranijih istraživanjaThe focus of this doctoral disertation is the preparation and characterization of selfhealing hybrid nanocomposite materials incorporating glass capillaries containing selfhealing agents, as well as the processing and characterization of hybrid nanocomposite materials with electrospun poly(styrene) (PS) fibers containing the first and the second generation Grubbs’ catalysts, separately. Non-woven mat of electrospun PS polymer fibers has a role of a network - the catalyst carrier, making it accessible in all parts of the composite. Electrospun PS fibers protect Grubbs’ catalyst from deactivation caused by the influence of an amine used as a hardener for the epoxy precursor, reacting with an epoxy precursor and the atmospheric conditions during processing of the composite material. The effect of the concentration of monomer and catalyst on the healing efficiency was investigated. Also, due to the fact that the composite materials are often exposed to various external conditions, influence of temperature changes on the efficiency was also investigated. Testing was conducted by comparing the absorbed impact energy before and after the healing. With the aim of identifying the resulting polymer that heals the material, different analyzes have been carried out, such as scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy (FTIR) and thermal degradation. Those analyzes showed that the system with electrospun PS fibers in the role of a Grubbs’ catalyst carrier is successful and it offers great potential in the field of self-healing hybrid nanocomposite materials. Based on our current knowledge, this possibility has not been the subject of earlier research