Two-dimensional filtering in the Fourier domain of transient grating coherent artifacts in time-resolved spectroscopy.

Removal of coherent artifacts is important in the analysis of time and wavelength resolved spectroscopy data. By taking advantage of the strong correlation between spectra acquired sequentially in time, artifact removal can be formulated as a 2D problem for improved effectiveness. This paper proposes a 2D method to remove transient grating coherent artifacts from femtosecond time-resolved spectroscopy data based on filtering in the Fourier domain, leading to better estimation of the material parameters from the measured data. The method is simple, intuitive, and light on computation resources. The effectiveness of the method is demonstrated with experimental data acquired from a bare gold film with and without coherent artifacts using mutually parallel and perpendicular pump/probe polarizations, as well as with more complex samples (nanostructured gold film on a glass substrate and rhodamine fluorophores in solution). The proposed method is expected to be applicable to coherent artifact removal in other types of time and wavelength-resolved spectroscopy data.

The quality and fertilizing ability of the ram semen cryopreserved around 40 years ago.

The aim of the study was to verify the quality of ram semen, frozen in 1982-1983, from the historical collection of the Bank of Biological Material of the National Research Institute of Animal Production. A total of 18 ejaculates from 3 Swiniarka type rams were analyzed to assess sperm motility (subjectively), total motility, progressive motility, sperm concentration (CASA), membrane integrity (SYBR-14/PI) and chromatin structure (SCSA). In order to determine sperm fertilizing ability 49 ewes were intracervically inseminated (200×106 sperm per AI) with frozen- thawed semen 12 and 24 hours after detection of estrus. Sperm motility parameters, membrane intact spermatozoa and DFI did not differ among the analyzed rams. Spermatozoa concentration was significantly higher for ram no. 2 than for rams no. 1 and 3. The lambing rates (27.3 to 36.0%) did not differ significantly for individual rams. The ram semen, which had been stored for around 40 years, showed satisfactory quality and fertilizing capacity, allowing for its use in artificial insemination.

Quality parameters and fertility of ram semen cryopreserved in egg yolk and soybean lecithin supplemented extenders.

The aim of the study was to investigate the effect of soybean lecithin as a substitute for egg yolk in milk and tris based extenders in ram semen cryopreservation. Twenty ejaculates were col- lected from four healthy, mature Wrzosówka rams (2-3 years of age). Each ejaculate was divided into four equal aliquots and diluted with four different extenders: 1) milk extender containing 5% egg yolk, 2) milk extender containing 1.5% soybean lecithin, 3) tris extender containing 20% egg yolk, 4) tris extender containing 1.5% soybean lecithin. Extended semen was loaded into 0.25 ml French straws, cooled and frozen in liquid nitrogen vapor. Total motility, curvilinear velocity, plasma membrane integrity and fertilizing ability of sperm were assessed after thawing. Total mo- tility was lower (p⟨0.05) in tris-soybean lecithin extender when compared to other extenders. Curvilinear velocity was higher (p⟨0.05) for spermatozoa cryopreserved in milk-soybean lecithin extender compared to other extenders tested. For the percentage of live sperm no significant difference was observed between extenders. The lambing rate were higher (not statistically signifi- cant) in ewes inseminated with semen doses frozen in milk-soybean lecithin extender (42.9%) than in the tris-egg yolk extender (16.7%). In conclusion, replacing the egg yolk with soybean lecithin was effective in milk but not in tris extender.

Reproductive Performance of Rabbit does Artificially Inseminated with Semen Supplemented with GnRH Analogue [des-Gly10, D-Ala6]-LH-RH Ethylamide.

The aim of the study was to evaluate, the ability of a GnRH synthetic analogue [des-Gly10, D-Ala6]-LH-RH ethylamide to induce ovulation in rabbit does using intravaginal administration. A total of 138 primiparous lactating does were randomly divided into 4 groups that at the time of insemination received following treatments for ovulation induction: 1 µg of buserelin administered intramuscularly (control group); 5 µg of [des-Gly10, D-Ala6]-LH-RH ethylamide added to the semen dose (D5 group); 10 µg of [des-Gly10, D-Ala6]-LH-RH ethylamide added to the semen dose (D10 group); 15 µg of [des-Gly10, D-Ala6]-LH-RH ethylamide added to the semen dose (D15 group). Kindling rates were 68.8% in D10 and 66.7% in D15 groups and were comparable to that obtained in the control group (72.2%). The kindling rate in group D5 (29.4%) was significantly lower than those recorded in the other groups. The number of live born kits was not significantly affected by the ovulation induction treatment. The results of this study show that [des-Gly10, D-Ala6]-LH-RH ethylamide added directly into the semen dose can effectively stimulate ovulation in rabbits. The dose of 10 µg of [des-Gly10, D-Ala6]-LH-RH ethylamide per doe was sufficient to produce results comparable to those obtained by intramuscular administration of buserelin.

Direct Observation of Optical Field Phase Carving in the Vicinity of Plasmonic Metasurfaces.

Plasmonic surfaces are mainly used for their optical intensity concentration properties that allow for enhancement of physical interaction like in nonlinear optics, optical sensors, or tweezers. Phase response in plasmonic resonances can also play a major role, especially in a periodic assembly of plasmonic resonators like metasurfaces. Here we show that localized surface plasmons collectively excited by a guided mode in a metallic nanostructure periodic chain present nonmonotonous phase variation along the 1D metasurface, resulting from both selective Bloch mode coupling and dipolar coupling. As shown by near-field measurements, the phase profile of the highly concentrated optical field is carved out in the vicinity of the metallic metasurface, paving the way to unusual local optical functions.

Design of metallic nanoparticle gratings for filtering properties in the visible spectrum.

Plasmonic resonances in metallic nanoparticles are exploited to create efficient optical filtering functions. A finite element method is used to model metallic nanoparticle gratings. The accuracy of this method is shown by comparing numerical results with measurements on a two-dimensional grating of gold nanocylinders with an elliptic cross section. A parametric analysis is then performed in order to design efficient filters with polarization dependent properties together with high transparency over the visible range. The behavior of nanoparticle gratings is also modeled using the Maxwell-Garnett homogenization theory and analyzed by comparison with the diffraction of a single nanoparticle. The proposed structures are intended to be included in optical systems that could find innovative applications.

Motility, mitochondrial membrane potential and ATP content of rabbit spermatozoa stored in extender supplemented with GnRH analogue [des-Gly10, D-Ala6]-LH-RH ethylamide.

The present study was aimed to determine the effect of GnRH analogue [des-Gly10, D-Ala6]-LH-RH ethylamide on the quality of rabbit spermatozoa stored at 17°C for 3 days. Semen from 5 bucks (13 ejaculates) was used in the experiment. Ejaculates were divided and diluted at a 1:10 ratio with rabbit semen extender Galap (IMV, France) (Control) or with Galap extender supplemented with GnRH analogue [des-Gly10, D-Ala6]-LH-RH ethylamide (50 µg/ml) and stored for 3 days. Sperm motility parameters, mitochondrial membrane potential (MMP) and ATP content were as- sessed on each day of the experiment. Motility analysis was performed using a computer-assisted sperm analysis (CASA) system. The following sperm motility parameters were recorded: total motile spermatozoa, progressively motile spermatozoa, curvilinear velocity, straight-line velocity, average path velocity, linearity, straightness and amplitude of lateral head displacement. MMP was evaluated using JC-1 fluorescent dye. ATP content was assessed using a bioluminescence method. The addition of GnRH analogue [des-Gly10, D-Ala6]-LH-RH ethylamide to Galap extender did not affect any of the quality parameters studied. However, in both groups (Control and GnRH), significant changes in motility parameters (except straight-line velocity) and proportion of spermatozoa showing high MMP and ATP content were observed throughout 3 days of storage.

Dual antiferromagnetic coupling at La0.67Sr0.33MnO3/SrRuO3 interfaces.

We have studied the magnetic hysteresis cycle of La0.67Sr0.33MnO3/SrRuO3 antiferromagnetically coupled bilayers, by magnetometry and polarized neutron reflectometry. A positive exchange bias as well as an unusual asymmetry are observed on the magnetic reversal process of the La0.67Sr0.33MnO3 layer. Through an extended Stoner-Wohlfarth model comprising the magnetic anisotropy of both layers, we give experimental evidence that this asymmetry originates from two different but well-defined antiferromagnetic coupling strengths at the interface between the two magnetic oxides. The possible origin of this dual coupling is discussed in view of our experimental results.

Iron-induced luminescence as a method for assessing lipid peroxidation of frozen-thawed goat spermatozoa.

Freezing/thawing procedures induce enhanced reactive oxygen species (ROS) formation in mammalian sperm and these ROS may be a cause for the decrease in sperm function following cryopreservation. In the present study, we used a chemiluminescence method to detect ROS-induced damage in goat spermatozoa. Iron-induced luminescence of fresh and frozen/thawed sperm cells was assessed using a luminometer. It was shown that the freezing/thawing procedure had a significant effect on some luminescence parameters. Semen freezing significantly increased the values of integral, peak max, T.half (rise) and T.max (peak) parameters. A significant correlation was observed between the percentage of motile spermatozoa and integral, peak max and T.half (rise) parameters. In conclusion, the results of the present study indicate that measurement of induced luminescence can be an alternative, sensitive and relatively simple method for assessing the effect of cryopreservation on oxidative damage to spermatozoa.

Effect of rabbit age on sperm chromatin structure.

The aim of this study was to determine the relationship between the age of male rabbits and the sperm chromatin structure. The studies involved the semen of New Zealand White rabbits between 5 and 28 months of age. A flow cytometry and sperm chromatin structure assay (SCSA) method was used to determine chromatin structure. The results of cytometric chromatin structure assay suggested a relatively high stability of sperm chromatin in the rabbit. Between 6 and 16 months of age, the mean percentage of sperm with damaged chromatin was the lowest and ranged from 1.7 to 2.4%. Decreased sperm chromatin stability was found in ejaculates taken from male rabbits less than 5 months and more than 20 months of age.

Sperm chromatin integrity of bucks transgenic for the WAP bGH gene.

The aim of the study was to compare sperm chromatin structure of transgenic and non-transgenic rabbits. In addition, the effect of chromatin structure on semen fertility was determined. Twenty male rabbits transgenic (TG) for WAP bGH gene (Edison Biotechnology Institute Ohio University, USA) and nine non-transgenic (NTG) males were used. Both TG and NTG rabbits were 13-18 months old. Semen was collected at 1-week intervals and 3-7 ejaculates from each rabbit were examined in total. Sperm chromatin abnormalities were measured flow cytometrically according to the Sperm Chromatin Structure Assay method: after chromatin denaturation by low pH, sperm cells were stained with metachromatic fluorochrome acridine orange. Spermatozoa with abnormal chromatin structure and, subsequently, higher degree of denaturation, showed a shift in red fluorescence. Two different methods of semen fertility estimation were used: (1) for TG rabbits, AI of superovulated does and calculation of percentages of fertilised eggs and embryos developing in vitro to the blastocyst stage; (2) for NTG rabbits, AI of non-stimulated does and calculation of percentages of pregnant does and mean litter sizes. The mean value of COMPalpha(t) was 3.71 for TG rabbits and 2.89 for NTG rabbits (no significant difference, t-test). The mean values of S.D.alpha(t) for the TG and NTG rabbits were 10.94 and 10.40 (no significant difference, t-test), respectively. There were no significant correlations between sperm chromatin structure of TG males and the percentages of fertilised eggs or embryos developing to the blastocyst stage. A statistically significant correlation (-0.68, P<0.05) was found between S.D.alpha(t) of NTG males and percentages of pregnant does. The results showed chromatin stability was not different for sperm obtained from TG versus NTG bucks. The presence of WAP bGH gene construct in the genome of transgenic rabbits did not cause any spermatogenesis process disturbances leading to the production of spermatozoa with damaged chromatin structure. This suggests that the mere presence of the introduced gene construct does not lead to any abnormalities in DNA and chromatin proteins interaction. The possible chromatin damages in transgenic animals should be attributed to the activity of the introduced gene. The relationships between chromatin structure and fertility are only significant for sperm from NTG bucks.