120 research outputs found
Uticaj BA i BA+GA4+7 na formiranje prevremenih granÄica na jednogodiÅ”njim sadnicama sorti jabuke
This study presents the influence of BA (6-benzyladenine) and BA+GA4+7 (6-benzyladenine + gibberellic acids 4 and 7) on feathering of one-year-old apple trees of two cultivars Jonagold and Äadel. Different concentrations of BA (300, 600, 1,200 and 1,800 mg L-1) and BA+GA4+7 (500, 1,000, 1,500 and 2,000 mg L-1) were applied, and two treatments for both chemicals were performed. The first treatment was applied at 70-cm height of nursery trees and the second 2 weeks later. Comparison was performed in relation to untreated control. An application of BA and BA+GA4+7 did not affect both rootstock and nursery tree diameter at 10 cm above the grafting union. Nursery trees of cultivar Jonagold were not influenced by treatments applied, whereas in cultivar Äadel, the treatment with BA+GA4+7 decreased apical growth of nursery trees. The development of sylleptic shoots in both cultivars tested was influenced by the type of growth regulator and concentration applied. Treatment with BA at 300 mg L-1 concentration in both cultivars tested did not influence total length and number of sylleptic shoots, as well as the number of sylleptic shoots longer than 20 cm. The most positive influence on all studied parameters was observed on nursery trees treated with the concentration of 1,200 mg L-1 BA. The lowest concentration of BA+GA4+7 (500 mg L-1) caused the low feathering of both studied cultivars. The higher concentrations (1,000, 1,500 and 2,000 mg L-1) similarly increased the number and total length of sylleptic shoots of nursery trees.U ovom radu je ispitivan uticaj BA (6-benziladenin) i BA+GA4+7 (6-benziladenin + giberelinska kiselina 4 i 7) na boÄno grananje jednogodiÅ”njih sadnica dve sorte jabuke Jonagold i Äadel. Primenjene su razliÄite koncentracije BA (300, 600, 1.200 i 1.800 mg L-1) i BA+GA4+7 (500, 1.000, 1.500 i 2.000 mg L-1) pri Äemu su kod oba hemijska jedinjenja tretmani izvedeni dva puta. Prvi tretman je izveden kada su sadnice bile visine 70 cm, a drugi tretman je izveden dve nedelje kasnije. Kontrola je bila bez tretiranja. Primena BA i BA+GA4+7 nije ispoljila uticaj na preÄnik podloge i sadnice na visini od 10 cm iznad spojnog mesta. Kod sadnica sorte Jonagold nisu registrovane razlike u vrÅ”nom porastu pod uticajem primenjenih tretmana, dok je kod sorte Äadel tretman sa BA+GA4+7 uticao na smanjenje vrÅ”nog porasta sadnica. Ustanovljeno je da su tip hemijskog regulatora i primenjena koncentracija uticali na razvoj prevremenih granÄica kod obe ispitivane sorte. Tretman sa BA u koncentraciji od 300 mg L-1 nije ispoljio uticaj na ukupnu dužinu i broj prevremenih granÄica, kao i na broj prevremenih granÄica dužih od 20 cm. Najpozitivniji uticaj na sve ispitivane parametre je zabeležen kod sadnica tretiranih sa BA u koncentraciji od 1.200 mg L-1. Najniža koncentracija BA+GA4+7 (500 mg L-1) je izazvala slabo grananje sadnica kod obe ispitivane sorte. VeÄe koncentracije (1.000, 1.500 i 2.000 mg L-1) su uslovile sliÄno poveÄanje broja i ukupne dužine prevremenih granÄica na sadnicama
Electrical Control of Structural and Physical Properties via Strong Spin-Orbit Interactions in Sr\u3csub\u3e2\u3c/sub\u3eIrO\u3csub\u3e4\u3c/sub\u3e
Electrical control of structural and physical properties is a long-sought, but elusive goal of contemporary science and technology. We demonstrate that a combination of strong spin-orbit interactions (SOI) and a canted antiferromagnetic Mott state is sufficient to attain that goal. The antiferromagnetic insulator Sr2IrO4 provides a model system in which strong SOI lock canted Ir magnetic moments to IrO6 octahedra, causing them to rigidly rotate together. A novel coupling between an applied electrical current and the canting angle reduces the NĆ©el temperature and drives a large, nonlinear lattice expansion that closely tracks the magnetization, increases the electron mobility, and precipitates a unique resistive switching effect. Our observations open new avenues for understanding fundamental physics driven by strong SOI in condensed matter, and provide a new paradigm for functional materials and devices
Natural radioactivity of some spring and bottled mineral waters from several central Balkan sites, as a way of their characterization
In this work, a study of the radioactive content of some spring and bottled mineral waters originating fi-om metamorphic rock areas was carried out. A high content of radium isotopes (Ra-226, Ra-228), was found by radiometric analysis in the spring waters: Studenica (Ra-226: 289 mBq/L), Cibutkovica (Ra-226: 92, 4 mBq/L, Ra-228: 610 mBq/L), and Crni Guber (Ra-226: 120 mBq/L, Ra-228: 1170 mBq/L). On the other hand, the radiochemical results showed a higher concentration of U-238 in the bottled mineral water samples (dissolved uranium concentrations were from 0.21 mBq[L, for Kopaonik to 71.5 mBq/L fo Skadarska) than in the spring water samples (dissolved uranium concentrations were very low approximate to 10 mBq/L). The concentrations of all the present naturally occuring radionuclides: U-238, U-234, Th-232, Th-230, Th-228, Ra-228 and Ra-226 were determined by alpha/gamma spectrometric analysis. The activity ratios U-234/U-238, Ra-226/Th-230 and Th-228/Th-232, Ra-228/Th-228 were calculated and are discussed as an indication of the radioactive disequilibrium in bothe the U-238 and Th-232 radioactive series. The high contents of radium isotopes with respect to the equilibrium values expected from the respective parents Th-232/(Th-232 series) and Th-230 (U-238 series) found in the spring water samples is the main evidence for the existence of significant radioactive disequilibrium in both the radioactive series
Evidence for a Low-Temperature Magnetic Ground State in Double-Perovskite Iridates with Ir\u3csup\u3e5+\u3c/sup\u3e(5\u3cem\u3ed\u3c/em\u3e\u3csup\u3e4\u3c/sup\u3e) Ions
We report an unusual magnetic ground state in single-crystal, double-perovskite Ba2YIrO6 and Sr-doped Ba2YIrO6 with Ir5+(5d4) ions. Long-range magnetic order below 1.7 K is confirmed by dc magnetization, ac magnetic susceptibility, and heat-capacity measurements. The observed magnetic order is extraordinarily delicate and cannot be explained in terms of either a low-spin S = 1 state, or a singlet Jeff = 0 state imposed by the spin-orbit interactions (SOI). Alternatively, the magnetic ground state appears consistent with a SOI that competes with comparable Hund\u27s rule coupling and inherently large electron hopping, which cannot stabilize the singlet Jeff = 0 ground state. However, this picture is controversial, and conflicting magnetic behavior for these materials is reported in both experimental and theoretical studies, which highlights the intricate interplay of interactions that determine the ground state of materials with strong SOI
Evidence for a Low-Temperature Magnetic Ground State in Double-Perovskite Iridates with Ir\u3csup\u3e5+\u3c/sup\u3e(5\u3cem\u3ed\u3c/em\u3e\u3csup\u3e4\u3c/sup\u3e) Ions
We report an unusual magnetic ground state in single-crystal, double-perovskite Ba2YIrO6 and Sr-doped Ba2YIrO6 with Ir5+(5d4) ions. Long-range magnetic order below 1.7 K is confirmed by dc magnetization, ac magnetic susceptibility, and heat-capacity measurements. The observed magnetic order is extraordinarily delicate and cannot be explained in terms of either a low-spin S = 1 state, or a singlet Jeff = 0 state imposed by the spin-orbit interactions (SOI). Alternatively, the magnetic ground state appears consistent with a SOI that competes with comparable Hund\u27s rule coupling and inherently large electron hopping, which cannot stabilize the singlet Jeff = 0 ground state. However, this picture is controversial, and conflicting magnetic behavior for these materials is reported in both experimental and theoretical studies, which highlights the intricate interplay of interactions that determine the ground state of materials with strong SOI
Fullerenol nanoparticles as a new delivery system for doxorubicin
Doxorubicin is a very potent chemotherapeutic drug, however its side effects limit its clinical use. The aim of this research was to investigate the properties of a fullerenol/doxorubicin nanocomposite, its potentially cytotoxic and genotoxic effects on malignant cell lines, as well as its toxicity towards zebra fish embryos. Chromatographic, NMR and mass spectral analysis of the nanocomposite imply that interactions between doxorubicin and fullerenol are non-covalent bonds. The stability of the nanocomposite was confirmed by the use of atomic force microscopy, dynamic light scattering and transmission electron microscopy. The nanocomposite, compared to the free doxorubicin at equivalent concentrations, significantly decreased the viability of MCF-7 and MDA-MB-231 cells. The flow cytometry results indicated that doxorubicin-loaded fullerenol could remarkably increase the uptake of doxorubicin suggesting that fullerenol might be a promising intracellular targeting carrier for the efficient delivery of antitumor drugs into tumor cells. The nanocomposite also affected cell cycle distribution. A genotoxicity test showed that the nanocomposite at all examined concentrations on MCF-7 and at lower concentrations on MDA-MB-231 cells caused DNA damage. Consequently, cell proliferation was notably reduced when compared with controls. Results of the zebrafish embryotoxicity assay showed a decreased overall toxicity, particularly cardiotoxicity and increased safety of the nanocomposite in comparison to doxorubicin alone, as manifested by a higher survival of embryos and less pericardial edema
Uticaj sive protivgradne mreže na kvalitet ploda borovnice (Vaccinium corymbosum L.) sorte "Bluecrop"
The main focus of our study was to investigate effects of the modified microclimate under a grey hail protection net (HPN) on biometrical fruit characteristics (fruit weight, index of fruit shape, and seed number per fruit) and nutritional value (soluble solid content - SSC, titratable acidity - TA, total anthocyanins - TACY, total phenolics - TPH and total antioxidant capacity - TAC) of the 'Bluecrop' highbush blueberry (Vaccinium corymbosum L.). The study was conducted in the 'Bluecrop' highbush blueberry plantation located in Mladenovac (Serbia) during two consecutive years (2013, 2014). The orchard was established using two-year-old nursery trees in spring 2011, at a planting density of 3,300 bushes per ha. The grey polyethylene net (SILVERLUXĀ®, Helios Group, Lurano, Italy) with a Leno wave structure and a mesh size of 2.8 x 8 mm was used. During the research period, light intensity was measured weekly at 12.00 hr using a digital lux-meter 'Peak teck' PT-5025 (Germany). Air temperature and relative humidity within the canopy were recorded using climate dataloggers (type DT-171, Shenzhen Flus Technology Co., Ltd, China) both under HPN and in the open field (OF). Twelve readings per treatment were taken at 2-hour intervals every day in each season. In both years of observation, light was reduced by 5-20% under HPN, whereby daily maximum temperature was 2.4Ā°C lower causing 4% higher daily minimum relative air humidity than in OF. 'Bluecrop' had significantly higher average fruit weights under HPN ranging from 1.93 g (2013) to 1.86 g (2014) in comparison to those observed in OF. The SSC did not differ between the treatments in 2014, whereas a significantly higher mean value was registered in the fruits harvested under HPN (12.8%) compared to those from OF in 2013. The mean TA was higher under HPN in 2014 (0.57%), whereas in 2013 a significantly higher TA content was found in OF (0.87%). HPN showed a positive effect on the TPH content (7.12 mg GA/g FW), but an almost 2-fold higher value was registered in 2013. Similar to this, TAC was 2.5-fold higher in 2013, without a significant effect of HPN in both experimental years.U ovom radu su ispitivani efekti izmenjene mikroklime pod sivom protivgradnom mrežom (PGM) na fiziÄke osobine ploda (masa ploda, indeks oblika ploda i broj semenki u plodu) i nutritivnu vrednost (sadržaj rastvorljive suve materije - RSM, ukupnih kiselina i ukupnih fenola, kao i ukupni antioksidativni kapacitet ploda) sorte borovnice "Bluecrop" (Vaccinium corymbosum L.). Ispitivanja su izvedena u periodu 2013-2014. godina, u zasadu borovnice koji se nalazi u blizini Mladenovca. Zasad je podignut u proleÄe 2011. godine sa trogodiÅ”njim sadnicama i gustinom sadnje od 3.300 žbunova po ha. Primenjena je siva PGM (SILVERLUXĀ®, Helios Group, Lurano, Italy), težine 48 g/m2, sa veliÄinom otvora 2,8 x 8 mm. Tokom perioda ispitivanja, intenzitet svetlosti je meren jedanput nedeljno u 12 h koriÅ”Äenjem luks metra "Peak teck" PT-5025 (Germany). Temperatura i relativna vlažnost vazduha su merene ureÄajem za evidentiranje podataka (engl. data logger, DT-171, Shenzhen Flus Technology Co., Ltd, China) na svaka 2 h pod PGM i na otvorenom polju (kontrolni tretman) od poÄetka cvetanja do kraja zrenja borovnice u obe ispitivane godine. Intenzitet svetlosti pod PGM je bio u proseku smanjen za 5-20% u obe eksperimentalne godine. Dnevne maksimalne temperature bile su za 2,4 oC niže pod PGM uslovljavajuÄi za 4% viÅ”u minimalnu dnevnu relativnu vlažnost vazduha u poreÄenju sa otvorenim poljem. ZnaÄajno veÄa proseÄna vrednost mase ploda kod ispitivane sorte borovnice registrovana je pod PGM u poreÄenju sa otvorenim poljem, i kretala se od 1,93 g (2013) do 1,86 g (2014). Sadržaj RSM se nije znaÄajno razlikovao izmeÄu tretmana u 2014. godini, dok je u 2013. godini znaÄajno poveÄanje registrovano u plodovima koji su ubrani pod PGM (12,8%) u poreÄenju sa otvorenim poljem (11,6%). ProseÄna vrednost sadržaja ukupnih kiselina je bila veÄa pod PGM u 2014. godini (0,57%), dok je u 2013. godini znaÄajno veÄi sadržaj pronaÄen u plodovima ubranim na otvorenom polju (0,87%). PGM je ispoljila pozitivan efekat na sadržaj ukupnih fenola (7,12 mg galne kis. g-1sv.m.pl.), meÄutim skoro dva puta viÅ”a vrednost je bila registrovana u 2013. godini. SliÄno sadržaju ukupnih fenola, ukupni antioksidativni kapacitet ploda je bio za 2,5 puta veÄi u 2013. godini, bez znaÄajnog uticaja PGM u obe ispitivane godine
Phenotype and envelope gene diversity of nef-deleted HIV-1 isolated from long-term survivors infected from a single source
<p>Abstract</p> <p>Background</p> <p>The Sydney blood bank cohort (SBBC) of long-term survivors consists of multiple individuals infected with attenuated, <it>nef</it>-deleted variants of human immunodeficiency virus type 1 (HIV-1) acquired from a single source. Long-term prospective studies have demonstrated that the SBBC now comprises slow progressors (SP) as well as long-term nonprogressors (LTNP). Convergent evolution of <it>nef </it>sequences in SBBC SP and LTNP indicates the <it>in vivo </it>pathogenicity of HIV-1 in SBBC members is dictated by factors other than <it>nef</it>. To better understand mechanisms underlying the pathogenicity of <it>nef</it>-deleted HIV-1, we examined the phenotype and <it>env </it>sequence diversity of sequentially isolated viruses (n = 2) from 3 SBBC members.</p> <p>Results</p> <p>The viruses characterized here were isolated from two SP spanning a three or six year period during progressive HIV-1 infection (subjects D36 and C98, respectively) and from a LTNP spanning a two year period during asymptomatic, nonprogressive infection (subject C18). Both isolates from D36 were R5X4 phenotype and, compared to control HIV-1 strains, replicated to low levels in peripheral blood mononuclear cells (PBMC). In contrast, both isolates from C98 and C18 were CCR5-restricted. Both viruses isolated from C98 replicated to barely detectable levels in PBMC, whereas both viruses isolated from C18 replicated to low levels, similar to those isolated from D36. Analysis of <it>env </it>by V1V2 and V3 heteroduplex tracking assay, V1V2 length polymorphisms, sequencing and phylogenetic analysis showed distinct intra- and inter-patient <it>env </it>evolution.</p> <p>Conclusion</p> <p>Independent evolution of <it>env </it>despite convergent evolution of <it>nef </it>may contribute to the <it>in vivo </it>pathogenicity of <it>nef</it>-deleted HIV-1 in SBBC members, which may not necessarily be associated with changes in replication capacity or viral coreceptor specificity.</p
A Mumps Outbreak in Vojvodina, Serbia, in 2012 Underlines the Need for Additional Vaccination Opportunities for Young Adults
In 2012, mumps was introduced from Bosnia and Herzegovina to Vojvodina, causing an outbreak with 335 reported cases. The present manuscript analyses the epidemiological and laboratory characteristics of this outbreak, identifies its main causes and suggests potential future preventive measures. Sera of 133 patients were tested for mumps-specific antibodies by ELISA and 15 nose/throat swabs were investigated for mumps virus RNA by RT-PCR. IgG antibodies were found in 127 patients (95.5%). Mumps infection was laboratory-confirmed in 53 patients, including 44 IgM and 9 PCR positive cases. All other 282 cases were classified as epidemiologically-confirmed. More than half of the patients (n = 181, 54%) were 20-29 years old, followed by the 15-19 age bracket (n = 95, 28.4%). Twice as many males as females were affected (67% versus 33%). Disease complications were reported in 13 cases (3.9%), including 9 patients with orchitis and 4 with pancreatitis. According to medical records or anamnestic data, 190 patients (56.7%) were immunized with two doses and 35 (10.4%) with one dose of mumps-containing vaccine. The Serbian sequences corresponded to a minor genotype G variant detected during the 2011/2012 mumps outbreak in Bosnia and Herzegovina. Vaccine failures, the initial one-dose immunization policy and a vaccine shortage between 1999 and 2002 contributed to the outbreak. Additional vaccination opportunities should be offered to young adults during transition periods in their life trajectories
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