Superfluid drag of two-species Bose-Einstein condensates in optical lattices

We study two-species Bose-Einstein condensates in quasi two-dimensional optical lattices of varying geometry and potential depth. Based on the numerically exact Bloch and Wannier functions obtained using the plane-wave expansion method, we quantify the drag (entrainment coupling) between the condensate components. This drag originates from the (short range) inter-species interaction and increases with the kinetic energy. As a result of the interplay between interaction and kinetic energy effects, the superfluid-drag coefficient shows a non-monotonic dependence on the lattice depth. To make contact with future experiments, we quantitatively investigate the drag for mass ratios corresponding to relevant atomic species.Comment: 6 pages, 4 figures. Accepted in its original form but minor changes have been don

Electron-phonon coupling in crystalline organic semiconductors: Microscopic evidence for nonpolaronic charge carriers

We consider electron(hole)-phonon coupling in crystalline organic semiconductors, using naphthalene for our case study. Employing a first-principles approach, we compute the changes in the self-consistent Kohn-Sham potential corresponding to different phonon modes and go on to obtain the carrier-phonon coupling matrix elements (vertex functions). We then evaluate perturbatively the quasiparticle spectral residues for electrons at the bottom of the lowest-unoccupied- (LUMO) and holes at the top of the highest-occupied (HOMO) band, respectively obtaining $Z_e\approx 0.74$ and $Z_h\approx 0.78$. Along with the widely accepted notion that the carrier-phonon coupling strengths in polyacenes decrease with increasing molecular size, our results provide a strong microscopic evidence for the previously conjectured nonpolaronic nature of band-like carriers in these systems.Comment: final, published versio

Incommensurate superfluidity of bosons in a double-well optical lattice

We study bosons in the first excited Bloch band of a double-well optical lattice, recently realized at NIST. By calculating the relevant parameters from a realistic nonseparable lattice potential, we find that in the most favorable cases the boson lifetime in the first excited band can be several orders of magnitude longer than the typical nearest-neighbor tunnelling timescales, in contrast to that of a simple single-well lattice. In addition, for sufficiently small lattice depths the excited band has minima at nonzero momenta incommensurate with the lattice period, which opens a possibility to realize an exotic superfluid state that spontaneously breaks the time-reversal, rotational, and translational symmetries. We discuss possible experimental signatures of this novel state.Comment: 4 pages, 5 figures

Risk Factors for Neonatal Sepsis and Method for Reduction of Blood Culture Contamination

Background: False-positive blood cultures findings may lead to a falsely increased morbidity and increased hospital costs.Method: The survey was conducted as retrospective - prospective study and included 239 preterm infants (born before 37 weeks of gestation) who were treated in Neonatal Intensive Care Unit (NICU) in Institute for Child and Youth Health Care of Vojvodina during one year (January 1st, 2012 to December 31st, 2012). The retrospective part of the study focused on examination of incidence of neonatal sepsis and determination of risk factors. In the prospective part of the study infants were sub-divided into two groups: Group 1- infants hospitalized in NICU during the first 6 months of the study; blood cultures were taken by the ‘’clean technique’’ and checklists for this procedure were not taken. Group 2- neonates hospitalized in NICU during last 6 months of the study; blood cultures were taken by ‘’sterile technique’’ and checklists for this procedure were taken.Results: The main risk factors for sepsis were prelabor rupture of membranes, low gestational age, low birth weight, mechanical ventilation, umbilical venous catheter placement, and abdominal drainage. Staphylococcus aureus and coagulase negative Staphylococcus were the most frequently isolated microorganisms in false-positive blood samples.Conclusions: Education of employees, use of checklists and sterile sets for blood sampling, permanent control of false positive blood cultures, as well as regular and routine monthly reports are crucial for successful reduction of contamination rates

The influence of pyrolysis conditions on hydrocarbons composition of the shale oil (Aleksinac oil shale, Serbia)

The amount and the composition of liquid hydrocarbons (HCs) obtained by pyrolysis of oil shale depend on kerogen type, as well as pyrolytic system and conditions [1]. The aim of this study was to compare HCs composition of bitumen isolated from raw oil shale samples (osh) and shale oils obtained by pyrolysis of oil shales in an open system (os) and close system (cs) (Table 1). Investigation has been made on immature outcrop oil shale samples (vitrinite reflectance of 0.41 % Rr) from the Aleksinac deposit (Serbia). Pyrolysis experiments were performed on the two selected samples, which have shown the highest quantity of total organic carbon (TOC > 13 %) and high HCs generation potential (Hydrogen Index, HI > 615 mg HCs/g TOC) in the studied sample set [2]. The HCs composition of the shale oils obtained by open system pyrolysis indicates low maturity. They are similar to distributions of HCs in bitumens isolated from raw (initial) oil shales (Table 1). Therefore open system pyrolysis can be useful for assessment of source and depositional environment of organic matter. On the other head, shale oils obtained by pyrolysis in the close system have distributions of HCs which correspond to higher maturity and they are similar to composition of HCs in crude oil, generated in early stage of “oil window” (Table 1). Therefore, for artificial generation of shale oil (from immature oil shale), having composition comparable to crude oil, the close system pyrolysis is required. CPI – Carbon Preference Index, calculated from distributions of n-alkanes; Rc – calculated vitrinite reflectance = 0.49 x C29ααα20S/20R + 0.33; / – Not determined due to the absence of C29 αββ 20Rsterane in these samples

Quantum simulation of small-polaron formation with trapped ions

We propose a quantum simulation of small-polaron physics using a one-dimensional system of trapped ions acted upon by off-resonant standing waves. This system, envisioned as an array of microtraps, in the single-excitation case allows the realization of the anti-adiabatic regime of the Holstein model. We show that the strong excitation-phonon coupling regime, characterized by the formation of small polarons, can be reached using realistic values of the relevant system parameters. Finally, we propose measurements of the quasiparticle residue and the average number of phonons in the ground state, experimental probes validating the polaronic character of the phonon-dressed excitation.Comment: accepted for publication in Phys. Rev. Let

Uticaj različitih načina pranja okrvavljene tkanine na ekspertizu tragova krvnih mrlja i rezultat DNK analize

In practice, there are often various attempts to remove traces of blood from items in order to conceal a crime. In the study, samples of bleached cotton fabric (360 samples in total) were used, which were then washed through one of six different washing cycles. After a period of time the samples were analyzed. The macroscopic appearance of the samples, the reaction of the samples to chemical tests for the presence of blood, quantity (concentration) of DNA, DNA degradation index and DNA profiles were analyzed. Machine washing at a temperature of 95 and 60oC using detergent can remove visible but not invisible traces of bloodstains up to 10 days old, while bloodstains aged 30 days cannot be removed in one washing cycle. Regardless of the method of washing, after washing, the visible remaining part of the bloodstain will be the dominant circumferential edge of the area of the original bloodstain. Comparative analysis with the results of DNA analysis revealed that washing older bloodstains from the cotton fabric makes it easier to remove the DNA, while the visual feature of bloodstains originating from hemoglobin is more difficult to remove in older bloodstains. The statistical significance of the DNA degradation index of the material remaining in the bloodstains after washing was revealed at the same time concerning the washing temperature (95 and 60oC) and the application of the detergent, with the existence of a synergistic enhancing effect of these two factors on the DNA degradation index. This pattern is completely absent in the sample group washed at 30oC. By comparing the results, it was concluded that different experimental conditions in this study, namely water temperature and detergent, affect different target parts of DNA (different STR loci) and thus accelerate the degradation of DNA. Therefore, early-stage DNA degradation does not occur uniformly in all parts of the genetic material, but this effect is lost with the passage of time and degradation becomes more alike in all parts of the DNA. This research identifies certain new scientific facts that provide forensic experts with a new perspective on concealing the traces of crime

Pharmacological action of serotonin and adenosine on rat femoral artery in experimental models of diabetes and vascular occlusion

Периферна артеријска болест (ПАБ) је хронично обољење, које настаје као последица развоја ендотелне дисфункције и последичне прогресије овог патолошког процеса према атеросклерози. Серотонин има значајну улогу у настанку и прогресији ПАБ. Са друге стране, аденозин се у циркулацију ослобађа током хипоксије како би се побољшао проток крви, што га чини и потенцијалним кандидатом за терпију ПАБ. Узимајућу у обзир ове чињенице, циљ ове дисертације је био да се испита утицај серотонина и аденозина на изолованој феморалној артерији (ФА) пацова соја Wistar, и то код здравих животиња, као и код дијабетичних животиња и/или животиња којима је додатно извршена оклузија ФА. Материјал и методе: Експерименти су извођени на мужјацима пацова соја Wistar (250 – 320 гр) . Животиње су чуване у поликарбонским кавезима (максимално 4 животиње). Услови живота су одржавани константним, тако да је температура износила 24±1 °C, влажност ваздуха је била 55±10%, а дневни циклус је одржаван тако да је 12 сати био дан и 12 сати ноћ. Животиње су имале слободан приступ води и стандардној пелетираној храни. Насумично, одабраним животињама изазиван је дијабетес помоћу алоксана (175 мг/кг). Неким здравим и дијабетичним животињама ФА је оклудирана током периода од 45 минута. Пре оклузије животиње су увођене у анестезију помоћу уретана (125 мг/ 100гр). У одвојеној групи животиња ендотелна дисфункција је изазивана помоћу никотина. Промене у васкуларном тону крвних судова су мерене након препарације прстенова крвних судова и урањања ових прстенова у органско купатило. Код неких насумично одабраних експерименталних животиња крв је узоркована из репне вене како би се квантификовали маркери показатељи ендотелне дисфункције. Резултати: Серотонин је изазвао контракцију ФА која је зависила од концентрације серотонина, а која је у групи здравих животиња, такође зависила и од присуства интактног слоја ендотелних ћелија...Peripheral artery disease (PAD) of lower limbs is a chronic disease that is associated with the occurrence of endothelial dysfunction (ED) and further progression of atherosclerosis in the affected arteries. Recent findings have demonstrated that serotonin is an important participant in the development and progression of PAD. On the other hand, adenosine, a purine nucleoside, is released during hypoxia and improves local blood flow, which is why it could be used as a potential therapeutic option in treatment of PAD. Considering these facts, the aim of this thesis was to investigate the effects of serotonin and adenosine on isolated Wistar rat femoral artery in both healthy and diabetic animals, with and without artery occlusion. Material and Methods: Experiments were performed on male Wistar rats (250 - 320 g). The rats were kept in polycarbonate cages (up to 4 per cage). During experimental process living conditions were maintained constant, with a half-half light/day cycle, temperature 24±1 °C, and humidity of 55±10%. Experimental animals had free access to bottles filled with tap water and pallets of standard rodent diet. In randomly selected rats, diabetes was induced with alloxan (175 mg/kg). In some healthy and diabetic animals, occlusion of femoral artery was performed for 45 minutes. Prior the occlusion, animals were anesthetized with urethane (125 mg/100g). In a separate group of animals ED was induced with nicotine. Vascular tone change was measured after artery rings were prepared and immersed in an organ bath. In some healthy, diabetic and nicotinetreated animals, blood was taken from rat tail vein and used for quantification of ED markers. Results: Serotonin induced concentration-dependent contraction of femoral artery, which was also endothelium-dependent, but only in a group of healthy animals. Endothelium-related part of serotonin contraction was reduced after incubation of losartan, and also it was dependant on extracellular calcium, while smooth musclereliant part was dependent on intracellular calcium..

Vodonična veza u push-pull 5-supstituisanim 2-alkiliden-4-oksotiazolidinima: 1H-NMR spektroskopsko proučavanje

Application of dynamic H-1-NMR spectroscopy added to the understanding of the hydrogen bonds existing in the structurally related 5-substituted-2-alklidene-4-oxothiazolidines in polar and apolar solvents. The equilibrated mixtures of these topical push-pull alkenes in CDCl3 consist of the intramolecularly H-bonded (E)-isomer and intermolecularly H-bonded (Z)-isomer in varying proportions which depend on the solvent polarity. For the representative of the series. (Z)-2-(5-ethoxycarbonylmethyl-4-oxothiazolidin-2-ylidene)-1-phenylethanone, a concentration effect on the degree of intermolecular hydrogen bonding in apolar CDCl3 has been studied.Primenom dinamičke 1H-NMR spektroskopije došlo se do boljeg razumevanja o vrsti vodoničnih veza koje postoje u strukturno sličnim 5-supstituisanim 2-alkiliden-4-oksotiazolidinima u polarnim i apolarnim rastvaračima. Uravnotežene smese ovih tipičnih push-pull alkena u CDCl3 sadrže (E)-izomer vezan intramolekulskom vodoničnom vezom kao i intermolekulski vodoničnom vezom vezan (Z)-izomer u različitim odnosima, koji zavise od polarnosti rastvarača. U slučaju tipičnog predstavnika serije (Z)-2-(5-etoksikarbonilmetil-4-oksotiazolidin- 2-iliden)-1-feniletanona uticaj koncentracije na stepen stvaranja intermolekulske vodonične veze u apolarnom CDCl3 je takođe proučavan

Does exposure to a single dose of microplastic represent a health risk?

Worldwide pollution with plastic debris represents tremendous environmental issue. Small particles originated from plastic bottles exert various effects in organisms when exposed chronically, while the effects of a single exposure are completely unknown. Thus, to test their potential health impact, male Wistar rats were exposed by oral gavage to a single dose of microplastic particles (MP) derived from polyethylene terephthalate (PET) bottles (1.4, 35 or 125 mg/kg with median diameter of 85 μm). Food and water intakes were monitored, and neurological and clinical tests were conducted. Obtained results point to lower food and water intakes in groups that received two higher MP doses indicating to interference with normal digestion. None of three used MP doses provoked neurological and clinical impairments either due to short-term exposure and/or lack of MP cumulative effect. Overall, presented results indicate that exposure to a single dose of MP can initiate health issues