On the hyperfine interaction in rare-earth Van Vleck paramagnets at high magnetic fields

An influence of high magnetic fields on hyperfine interaction in the rare-earth ions with non-magnetic ground state (Van Vleck ions) is theoretically investigated for the case of $Tm^{3+}$ ion in axial symmetrical crystal electric field (ethylsulphate crystal). It is shown that magnetic-field induced distortions of $4f$-electron shell lead to essential changes in hyperfine magnetic field at the nucleus. The proposed theoretical model is in agreement with recent experimental data.Comment: 4 pages, no figures, submitted to J. Phys. : Cond. Mat

Proliferative activity of bone marrow cells of rats under the influence of biologically active substances of a medical leech

Hirudotherapy has been used in medicine since time immemorial. The advantage of this type of treatment is that the bite of a leech has a restorative effect on the entire body. The leech bites the skin and injects into the patient’s blood biologically active substances that activate blood microcirculation and promote immunity. The saliva of the leech contains more than 100 substances that contribute to the spectrum of therapeutic effects. But there are no studies on the effect of hirudotherapy on the proliferation of bone marrow cells, which is ontogenetically primary in the development of myeloid and lymphoid tissues. Therefore, it is important to study the mitotic activity of bone marrow of rats at the early stages of postembryonic development against the background of influence by the leech. Female nonlinear rats, two weeks before and two weeks after mating with males, were presented each week to one hungry medical leech weighing 400 mg. The females were examined after feeding their offspring and their offspring were likewise examined on day 1, 15, 30, 45, 60 of the experiment. The animals were kept in vivarium conditions on a standard diet in individual cages. All animals were decapitated under ether anesthesia and the number of leukocytes, the leukocyte blood count, the number of erythrocytes, hemoglobin, and the color index were examined. After that, the femurs were quickly removed and the adjacent muscles separated with a sterile gauze. We cut the epiphyses and cut along the bone. Bone marrow from the femur was flushed with a warm (37 °C) hypotonic 0.9% sodium citrate solution into a sterile centrifuge tube using a Pasteur pipette. The resulting cell suspension was incubated in a hypotonic solution for 10 minutes at 37 °C. The resulting suspension was centrifuged for 5 minutes at 1000 rpm leaving only a small residue of sediment in the test tube. The cells were fixed in methyl alcohol with glacial acetic acid (three parts methyl alcohol and one part acetic acid). 3,000 cells were analyzed, among which we determined those that are in mitosis, and expressed their share. As a result of our studies, the immunomodulating effect of the saliva of the medical leech was revealed, which manifested itself in an increase in the proliferative activity of bone marrow cells, which led to an increase in the number of red blood cells, increased hemoglobin and increase in the number of leukocytes. The color index and the leukocyte blood count were within the normal limits

Potential effects of horizontal gene exchange in the human gut

© 2017 Lerner, Matthias and Aminov. Many essential functions of the human body are dependent on the symbiotic microbiota, which is present at especially high numbers and diversity in the gut. This intricate host-microbe relationship is a result of the long-term coevolution between the two. While the inheritance of mutational changes in the host evolution is almost exclusively vertical, the main mechanism of bacterial evolution is horizontal gene excha nge. The gut conditions, with stable temperature, continuous food supply, constant physicochemical conditions, extremely high concentration of microbial cells and phages, and plenty of opportunities for conjugation on the surfaces of food particles and host tissues, represent one of the most favorable ecological niches for horizontal gene exchange. Thus, the gut microbial system genetically is very dynamic and capable of rapid response, at the genetic level, to selection, for example, by antibiotics. There are many other factors to which the microbiota may dynamically respond including lifestyle, therapy, diet, refined food, food additives, consumption of pre- and probiotics, and many others. The impact of the changing selective pressures on gut microbiota, however, is poorly understood. Presumably, the gut microbiome responds to these changes by genetic restructuring of gut populations, driven mainly via horizontal gene exchange. Thus, our main goal is to reveal the role played by horizontal gene exchange in the changing landscape of the gastrointestinal microbiome and potential effect of these changes on human health in general and autoimmune diseases in particular

Classical and quantum dynamics of confined test particles in brane gravity

A model is constructed for the confinement of test particles moving on a brane. Within the classical framework of this theory, confining a test particle to the brane eliminates the effects of extra dimensions, rendering them undetectable. However, in the quantized version of the theory, the effects of the gauge fields and extrinsic curvature are pronounced and this might provide a hint for detecting them. As a consequence of confinement the mass of the test particle is shown to be quantized. The condition of stability against small perturbations along extra dimensions is also studied and its relation to dark matter is discussed.Comment: 15 pages, no figures, extended, references adde

Rat peripheral blood leukocyte subset composition, hemogram, lymphoid organ and body morphometry after exposure to biologically active substances derived from Hirudo verbana saliva

Medical community has noted that the prevalence of allergic diseases by steadily tends to rise resulting from using synthetic drugs ecological catastrophe. In this regard, more and more attention is increasingly being paid to natural therapeutic approaches, one of which is based on applying hirudotherapy. There were used 40 pubescent outbred female rats and their 200 pups born during experiment. In particular, female rats underwent leeching in the subscapular region 2 weeks before and 2 weeks after mating by applying medical leeches weighing 400 ± 10 mg. Next, relevant progeny was examined at day 1, 15, 30, 45, and 60 after birth, whereas female rats– after weaning. Experiment was designed to assess diverse parameters in accordance with the age-related rat development: newborn pups – 1-5 days old, day 6-21 – suckling period, day 22-50 – onset of puberty, day 60 onward – puberty. After measuring body morphometric parameters, female rats were sacrificed by decapitation under ether narcosis on day 60, whereas rat pups – at various time points. followed by autopsy and collecting blood sample into a sterile centrifuge tube by using 2% Spofa crystalline heparin (8:1) to be further examined by standard assays: morphometry of rat body, spleen and thymus; measuring total leukocyte count; CBC with differential; RBC; hemoglobin level; color index. Statistical data processing was performed by calculating arithmetic mean, error of arithmetic mean, standard deviation by using SPSS version 21.0 and Microsoft Office Excel 2010 software. Significance of differences was estimated by using Student's t test, and set at p≤0.05. Our study demonstrated medical leech saliva components applied during hirudolotherapy exerted an immune-augmenting effect of on morphometric body, thymus and spleen parameters. Moreover, starting from day 1, total leukocyte count, RBC, and hemoglobin level were increased in the experimental group. Moreover, we convincingly demonstrated a stimulatory effect of medical leech saliva components on histogenetic reactions at various ontogenetic stages in both female rats and their progeny. In the former, such morphogenetic effect was maintained for more than 70 days after the last leeching: on week 2 after mating and 30 days after delivery. Changes in morphological and hematological evidence about enhanced morphogenetic function of immune system in response to saliva-derived biologically active substances released by medicinal leeches

Temperature dependence of the EPR linewidth of Yb3+ - ions in Y0.99Yb0.01Ba2Cu3OX compounds: Evidence for an anomaly near TC

Electron paramagnetic resonance experiments on doped Yb3+ ions in YBaCuO compounds with different oxygen contents have been made. We have observed the strong temperature dependence of the EPR linewidth in the all investigated samples caused by the Raman processes of spin-lattice relaxation. The spin-lattice relaxation rate anomaly revealed near TC in the superconducting species can be assigned to the phonon density spectrum changesComment: 10 pages, 4 figures Renewed versio

Luminescence of Tl+ ions in a KZnF3 crystal

The luminescence spectra of a KZnF3: Tl+ crystal are investigated in the energy range from 4.75 to 5.9 eV at temperatures of 10-300 K upon excitation into the A absorption band (5.7-6.3 eV). At T = 300 K, the luminescence spectra exhibit an intense band with a maximum at 5.45 eV, which is attributed to single Tl+ ions substituted for K+ ions. The 5.723-eV intense narrow band observed at T < 20 K is assigned to the 3Γ1u-1Γ1g zero-phonon transition, which is weakly allowed by the hyperfine interaction. The luminescence decay is studied as a function of temperature. The main characteristics of the luminescence spectra are adequately described in terms of the semiclassical theory based on the Franck-Condon principle and the Jahn-Teller effect for an excited sp configuration of the Tl+ ion with the use of the parameters obtained earlier from analyzing the absorption spectra of the system under investigation. © 2002 MAIK "Nauka/Interperiodica"

EPR Evidence of Unusual Dopant Valency States in Nanocrystalline Er-doped CeO<inf>2</inf>

© 2015, Springer-Verlag Wien. The structure and oxidation state of the Er dopant cation in CeO2 single crystal and nanocrystals with size ranging from 22 to 300 nm are studied using electron paramagnetic resonance (EPR) spectroscopy at X- and at Q-band near liquid-He temperatures. Besides the expected EPR line due to Er3+ in cubic sites in the lattice, unusual EPR lines with g values around 14 and 20 are observed in nanocrystalline CeO2. The appearance of these lines suggests the formation of non-Kramers Er2+, Er4+ ions, which becomes increasing favorable with decreasing nanoparticle size. Formation of rare earth ions with such unusual oxidation states in nanoparticles can be exploited in tuning their catalytic activity and optical properties

Stabilization of test particles in Induced Matter Kaluza-Klein theory

The stability conditions for the motion of classical test particles in an $n$-dimensional Induced Matter Kaluza-Klein theory is studied. We show that stabilization requires a variance of the strong energy condition for the induced matter to hold and that it is related to the hierarchy problem. Stabilization of test particles in a FRW universe is also discussed.Comment: 15 pages, 1 figure, to appear in Class. Quantum Gra