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Human dirofilariosis is a relatively rare infection caused by filarial worms of the genus Dirofilaria. We herein report the first case of human subcutaneous dirofilariosis in the southeastern part of Serbia. A complete alive nematode was removed from a nodule in the periorbital region of a 50-year-old woman. The nematode was morphologically identified as a D. repens-like immature female. The diagnosis was confirmed with molecular methods. The patient was probably infected in the South-East Serbia as she had not travelled abroad, nor in other parts of Serbia such as Vojvodina, recently identified as a hyperendemic area for D. repens infection of dogs.

We present a systematic study of the electronic- and spin-excitation dynamics associated with the sequence of spin- and orbital-ordering phase transformations in the complex vanadates YVO3 and GdVO3 with ultrafast optical pump-probe reflectance spectroscopy. Relaxation dynamics occurs on a different time scale for each of the ordering transitions, which enables us to unambiguously associate the critical behavior in the dynamics with the observed ordering phenomena. Spin-ordering dynamics is observed on two time scales: tau(r) similar or equal to 2 ps (rise time) and tau(s) similar or equal to 300-3000 ps (decay time), observed below T-N in both compounds. In contrast, the relaxation dynamics associated with orbital ordering occurs in YVO3 on a time scale of tau(o) similar or equal to 20-50 ps. From the temperature dependence of the dynamics, we observe that in both the G-type and C-type orbitally ordered (OO) phases of YVO3 spin order develops in a second-order mean-field fashion with the Neel temperature of the C-OO phase found from our data T-N(C) = 83 +/- 7 K. In GdVO3 we identify the emergence of a new ordered phase within the phase-separated state below 60 K. A new response component with a lifetime of similar to 60 ps is observed below 60 K together with other anomalies in the Delta R/R(Delta t) data. This new phase is not resolved in x-ray diffraction and is not present in YVO3. AB - We present a systematic study of the electronic- and spin-excitation dynamics associated with the sequence of spin- and orbital-ordering phase transformations in the complex vanadates YVO3 and GdVO3 with ultrafast optical pump-probe reflectance spectroscopy. Relaxation dynamics occurs on a different time scale for each of the ordering transitions, which enables us to unambiguously associate the critical behavior in the dynamics with the observed ordering phenomena. Spin-ordering dynamics is observed on two time scales: tau(r) similar or equal to 2 ps (rise time) and tau(s) similar or equal to 300-3000 ps (decay time), observed below T-N in both compounds. In contrast, the relaxation dynamics associated with orbital ordering occurs in YVO3 on a time scale of tau(o) similar or equal to 20-50 ps. From the temperature dependence of the dynamics, we observe that in both the G-type and C-type orbitally ordered (OO) phases of YVO3 spin order develops in a second-order mean-field fashion with the Neel temperature of the C-OO phase found from our data T-N(C) = 83 +/- 7 K. In GdVO3 we identify the emergence of a new ordered phase within the phase-separated state below 60 K. A new response component with a lifetime of similar to 60 ps is observed below 60 K together with other anomalies in the Delta R/R(Delta t) data. This new phase is not resolved in x-ray diffraction and is not present in YVO3.

We present a systematic study of the electronic- and spin-excitation dynamics associated with the sequence of spin- and orbital-ordering phase transformations in the complex vanadates YVO3 and GdVO3 with ultrafast optical pump-probe reflectance spectroscopy. Relaxation dynamics occurs on a different time scale for each of the ordering transitions, which enables us to unambiguously associate the critical behavior in the dynamics with the observed ordering phenomena. Spin-ordering dynamics is observed on two time scales: τr 2ps (rise time) and τs 300-3000ps (decay time), observed below TN in both compounds. In contrast, the relaxation dynamics associated with orbital ordering occurs in YVO3 on a time scale of τo 20-50ps. From the temperature dependence of the dynamics, we observe that in both the G-type and C-type orbitally ordered (OO) phases of YVO3 spin order develops in a second-order mean-field fashion with the Nèel temperature of the C-OO phase found from our data TNC =83±7K. In GdVO3 we identify the emergence of a new ordered phase within the phase-separated state below 60 K. A new response component with a lifetime of ∼60ps is observed below 60 K together with other anomalies in the ΔR/R (Δt) data. This new phase is not resolved in x-ray diffraction and is not present in YVO3. © 2010 The American Physical Society.

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This study is aimed to highlight the possibility of using the corona treatment for fiber surface activation that can facilitate the loading of silver nanoparticles from colloids onto the polyester and polyamide fabrics and thus enhance their antifungal activity against Candida albicans. Additionally, the laundering durability of achieved effects was studied. Corona activated polyamide and polyester fabrics loaded with silver nanoparticles showed better antifungal properties compared to untreated fabrics. The positive effect of corona treatment became even more prominent after 5 washing cycles, especially for polyester fabrics. Publications of the Astronomical Observatory of Belgrade Series, 24th Summer School and International Symposium on Physics of Ionized Gases, Aug 25-29, 2008, Novi Sad, Serbia

Magnetic properties of high purity stoichiometric La2 Cu O4 nanoparticles are systematically investigated as a function of particle size. Ferromagnetic single-domain spin clusters are shown to spontaneously form at the surface of fine grains as well as paramagnetic defects. Hysteresis loops and thermomagnetic irreversibility are observed in a wide temperature range 5-350 K with the remnant moment and coercivity gradually decreasing with increasing temperature. Possible origins of the spontaneous surface ferromagnetic clusters and the relation of our data to the appearance of unusual magnetic phenomena and phase separation of doped cuprates are discussed. © 2007 The American Physical Society.

The infrared photo-induced spectra of the isotope-substituted stoichiometric La 2CuO 4 samples were studied at T=20 K. Measured spectra were analyzed within the small polaron hopping theory. A small, but detectable shift of the effective phonon frequency on the substitution 16O to 18O is found for the high-energy surface carrier associated band (~4000 cm -1) and has a value of α O = 0.3 ±0.2. The low-energy band (~1500 cm -1) originating from the bulk carriers doesn't show any difference within experimental error which is fully in agreement with theory predictions. The isotope shifts of the optically active oxygen-related phonon modes are described well by the harmonic approximation. © EDP Sciences/Società Italiana di Fisica/Springer-Verlag 2006.

The quasiparticle (QP) dynamics with different symmetry is investigated in the superconducting (SC) and normal state of the high-temperature superconductor Bi2Sr2CaCu2O8+delta (Bi2212) using optical pump-probe experiments with different light polarizations at different doping levels. The observation of distinct selection rules for SC excitations present in A(1g) and B-1g symmetries, and for the pseudogap (PG) excitations present in A(1g) and B-2g symmetries by the probe, and absence of any dependence on the pump beam polarization leads to the unequivocal conclusion of the existence of a spontaneous spatial symmetry breaking in the PG state not limited to the sample surface.

We report on the discovery of a re-entrant spin glass phase in alpha -TDAE-C-60. Apart from a behaviour associated with the ferromagnetic transition at 16K, the linear AC susceptibility of alpha -TDAE-C-60 shows a small decrease below 10 K in the real part and an additional broad peak at T-RSG = 7 K in the imaginary part, which is also frequency dependent. In addition, among higher harmonics of the AC response, which correspond to the non-linear susceptibility, only the odd harmonics show a peak at T-RSG - contrary to the ferromagnetic transition at T-c = 16 K where both the odd and even harmonics show a divergence.

The low-energy electronic excitation spectrum and gap structure in optimally doped and overdoped Y_{1-x}Ca_{x}Ba_{2}Cu_{3}O_{7-��} single crystals are investigated by real-time measurements of the quasiparticle relaxation dynamics with femtosecond optical spectroscopy. From the amplitude of the photoinduced reflectivity as a function of time, temperature and doping x we find clear evidence for the coexistence of two distinct gaps in the entire overdoped phase. One is a temperature-independent pseudogap $��_{p}$ and the other is a T-dependent collective gap $��_{c}(T)$ which has a BCS-like T-dependence closing at Tc. From quasiparticle relaxation time measurements above Tc we ascertain that fluctuations associated with the collective gap $��_{c}(T)$ are limited to a few K, consistent with time-dependent Ginzburg-Landau theory and are distinct from the pseudogap whose presence is apparent well above Tc for all x., 4 pages, 4 figures, accepted for publication in Phys.Rev.Lett

Photoinduced IR absorption was measured in (La(1-x)Sr(x)Mn)(1-��)O3. A midinfrared peak centered at ~ 5000 cm$^{-1}$ was observed in the x=0 antiferromagnetic sample. The peak diminishes and softens as hole doping is increased. The origin of the photoinduced absorption peak is atributted to the photon assisted hopping of anti-Jahn-Teller polarons formed by photoexcited charge carriers, whose binding energy decreases with increasing hole doping. The shape of the peak indicates that the polarons are small., 5 pages, 3 figures, submitted to PRB

Time-resolved optical measurements give information on the quasiparticle relaxation dynamics in YBCO, from which the evolution of the gap with doping and temperature can be systematically deduced. In this paper these optical charge-channel `pseudogap' data are compared with the `pseudogap' obtained from the NMR Knight shift Ks, spin polarized neutron scattering (SPNS) and single particle tunneling measurements. A simple energy level diagram is proposed to explain the different `gap' magnitudes observed by different spectroscopies in Y1-xCaxBa2Cu3O7-y, whereby the spin gap Delta_s in NMR and SPNS corresponds to a triplet local pair state, while Delta_p in the charge excitation spectrum corresponds to the pair dissociation energy. At optimum doping and in the overdoped state, an additional T-dependent gap becomes evident, which closes at T_c, suggesting a cross-over to a more conventional BCS-like superconductivity scenario., Comment: 9 pages, 4 figures. Presented in HTS99, Miami, January 99

Ultrafast time-resolved optical spectroscopy in high-temperature superconductors enables the direct real-time measurement of non-equilibrium quasiparticle recombination dynamics. In addition, it also gives detailed information about the symmetry of the superconducting gap and the "pseudogap", their doping dependence and their temperature dependence. Experimental data, together with theoretical models on the photoinduced transmission amplitude and relaxation time as a function of temperature and doping in YBa2Cu3O7-d gives a consistent picture of the evolution of low-energy structure, where a temperature-independent gap is shown to exist in the underdoped state which evolves with doping into a two-component state near optimum doping, where the dominant response is from a T-dependent BCS-like superconducting gap., Comment: 15 pages, to be published in "Spectroscopy of Superconducting Materials", ACS Symposium Series Volume 730, 1999, Ed. E. Faulques

Ultrafast transient reflectivity changes caused by collective and single particle excitations in the quasi one-dimensional charge-density wave (CDW) semiconductor K0.3MoO3 are investigated with optical pump-probe spectroscopy. The temperature-dependence of non-equilibrium single particle excitations across the CDW gap and their recombination dynamics are reported for the first time. In addition, amplitude mode reflectivity oscillations are observed in real time. A T-dependent overdamped response is also observed which is attributed to relaxation of the phason mode., Comment: 5 pages, 4 figures, accepted for publication in Phys.Rev.Lett

We report new time-resolved data of quasiparticle relaxation and Cooper pair recombination dynamics in YBa_2Cu_3O_{7-\delta}, measured as a function of temperature and doping \delta using femtosecond optical spectroscopy. The data show the existence of a normal state pseudo-gap for in-plane charge excitations below T* and an unusual divergence of the quasiparticle relaxation time in the superconducting state \tau_s with \delta towards optimum doping. In the underdoped state, no change in the amplitude of the induced transmission (which is proportional to the DOS at E_F), or relaxation time \tau_s is observed at T_c. From the sum rule, both observations signify that no gap opens at T_c in underdoped YBCO for \delta >0.15. T_c in this case only signifies the onset of phase coherence. The presented data thus suggest pair formation with an associated redistribution of the DOS starting at T* and the establishment of phase coherence at T_c consistent with Bose-Einstein condensation. In the optimally doped material, \delta ~ 0.1, on the other hand, both a divergence in lifetime and a change of the DOS occur at T_c, signifying the opening of a gap and the occurence of pairing takes place simultaneously., Comment: 5 pages, 4 figures

Analysis of the a-b plane optical conductivity $\sigma_{ab}$ for both twinned and untwinned YBa$_{2}$Cu$_{3}$O$_{7-\delta}$ as a function of temperature and doping shows that below a well defined temperature T*, a dip in the spectrum systematically appears separating the infrared charge excitation spectrum into two components with distinct energy scales. The change from monotonic behaviour in $\sigma_{ab}$ is found to be concurrent with the onset of phonon anomalies in Raman and infrared spectra below T*. The optical data are suggested to be evidence for the appearance of an inhomogeneous distribution of carriers rather than the opening of a simple gap for charge excitations below T*, an interpretation wich is consistent with recent angle-resoved photoemission and electronic Raman spectra. We find that the behaviour below T* and the absence of any anomalies at Tc can be interpreted assuming a Bose-Einstein condensation of preformed pairs., Comment: 6 pages, 4 figures