Energetic compounds containing a new explosophoric fragment, (3,4-dinitro-1
H
-pyrazol-1-yl)-
NNO
-azoxy group, and furazan rings linked by azo and azoxy bridges were synthesized. Furazans obtained ...combine a high calculated enthalpy of formation and acceptable thermal stability and are of interest as potential components of energy-rich materials.
Mathematical modeling uses a wide variety of mathematical methods and concepts, in particular, an ergodic theory that studies statistical properties of motions in measure spaces (dynamic systems). ...The article is devoted to a further study of the statistical properties of a dynamic system generated by number-theoretic endomorphisms. An estimate of the convergence rate in the central limit theorem for sums of functions from number-theoretic endomorphisms trajectories is obtained. The obtained results may be of interest to practitioners using the theory of dynamic systems and specialists in number theory.
There is considered the generalized Bernoulli tests scheme in which it is assumed that the tests are connected unlike the usual Bernoulli tests scheme. There is defined the condition of weak ...dependence of tests. The integral limit theorem is proved for the distribution of the number of successes in carrying out a finite set of tests. There is investigated the convergence rate in the limit theorem. There is obtained the optimal remainder.
The experiment was carried out on 120 female white Wistar rats, to study the endothelio- and osteoprotective action of the combination of rosuvastatin with L-norvaline in the model of experimental ...osteoporosis. It was found that, after ovariectomy in rats, endothelial dysfunction of the vessels of the microcirculatory bed of bone tissue develops, leading to the appearance of osteoporosis, but the combination of the studied drugs prevents the decrease in the level of microcirculation in the bone tissue, thereby preventing the thinning of bone trabeculae and preventing the occurrence of microfractures in them.
Model experimental studies are presented for the flow field of a single jet, the flow parameters of a block jet, the pressure distribution on the bottom screen, and the parameters of the jet flow ...from a model nozzle. When expanding into a vacuum and/or a highly rarefied medium, the conditions for reproducing the relative gas pulse value of the full-scale nozzle block section are met. It is shown that when using specific similarity criteria, it is possible to experimentally model the supersonic jet outflow processes of space vehicles on small-sized laboratory vacuum installations, similar to the one created at Novosibirsk State University. Simulation results using spectral density measurements based on the glow excited by a focused electron beam, longitudinal and transverse jet density profiles obtained using modern scanning technology, as well as measurements of bottom pressure near the nozzle block are given. The possibilities and features of each applied registration method are discussed.
To evaluate the efficiency of gene delivery in gene therapy strategies for malignant brain tumors, it is important to determine the distribution and magnitude of transgene expression in target tumor ...cells over time. Here, we assess the time- and vector dose-dependent kinetics of recombinant herpes simplex virus (HSV)-1 vector-mediated gene expression and vector replication in culture and in vivo by a recently developed radiotracer method for noninvasive imaging of gene expression (J. G. Tjuvajev et al., Cancer Res., 55: 6126-6132, 1995). The kinetics of viral infection of rat 9L gliosarcoma cells by the replication-conditional HSV-1 vector, hrR3, was studied by measuring the accumulation rate of 2-14C-fluoro-5-iodo-1-beta-D-arabinofuranosyl-uracil (FIAU), a selective substrate for viral thymidine kinase (TK). The level of viral TK activity in 9L cells was monitored by the radiotracer assay to assess various vector doses and infection times, allowing vector replication and spread. In parallel, viral yields and levels of Escherichia coli beta-galactosidase activity were assessed quantitatively. To study vector replication, spread and HSV-1-tk and lacZ gene coexpression in vivo, first- or second-generation recombinant HSV-1 vectors (hrR3 or MGH-1) were injected into s.c. growing rat 9L or human U87 deltaEGFR gliomas in nude rats at various times (8 h to 8 days) and at various vector doses 1 x 10(6) to 2 x 10(9) plaque-forming units (PFUs) prior to imaging. For noninvasive assessment of HSV-1-tk gene expression (124I-labeled FIAU % dose/g), 0.15 mCi of 124I-labeled FIAU was injected i.v. 8 h after the last vector administration, and FIAU positron emission tomography (PET) was performed 48 h later. For the assessment of HSV-1-tk and lacZ gene coexpression, 0.2 mCi of 131I-labeled FIAU was injected i.v. 24 h after the last vector administration. Forty-eight h later, animals were killed, and tumors were dissected for quantitative autoradiographical and histochemical assessment of regional distribution of radioactivity (TK expression measured as 131I-labeled FIAU % dose/g) and coexpressed lacZ gene activity. The rates of FIAU accumulation (Ki) in hrR3-infected 9L cells in culture, which reflect the levels of HSV-1-tk gene expression, ranged between 0.12 and 3.4 ml/g/min. They increased in a vector dose- and infection time-dependent manner and correlated with the virus yield (PFUs/ml), where the PFUs:Ki ratios remained relatively constant over time. Moreover, a linear relationship was observed between lacZ gene expression and FIAU accumulation 5-40 h after infection of 9L cells with a multiplicity of infection of 1.5. At later times (> 52 h postinjection), high vector doses (multiplicity of infection, 1.5) led to a decrease of FIAU accumulation rates, viral yield, and cell pellet weights, indicating vector-mediated cell toxicity. Various levels of HSV-1-tk gene expression could be assessed by FIAU-PET after in vivo infection of s.c. tumors. The levels of FIAU accumulation were comparatively low (approximately ranging from 0.00013 to 0.003% injected dose/g) and were spatially localized; this may reflect viral-induced cytolysis of infected tumor cells and limited lateral spread of the virus. Image coregistration of tumor histology, HSV-1-tk related radioactivity (assessed by autoradiography), and lacZ gene expression (assessed by beta-galactosidase staining) demonstrated a characteristic pattern of gene expression around the injection sites. A rim of lacZ gene expression immediately adjacent to necrotic tumor areas was observed, and this zone was surrounded by a narrow band of HSV-1-tk-related radioactivity, primarily in viable-appearing tumor tissue. These results demonstrate that recombinant HSV-1 vector-mediated HSV-1-tk gene expression can be monitored noninvasively by PET, where the areas of FIAU-derived radioactivity identify the viable portion of infected tumor tissue that retains FIAU accumulation ability, and that the accumulation rate of FIAU in culture, Ki, reflects the number of HSV-1 viral particles in the infected tumor cell population 4.1 +/- 0.6 x 10(6) PFUs/Ki unit (PFUs divided by ml/min/g). Moreover, time-dependent and spatial relationships of HSV-1-tk and lacZ gene coexpression in culture and in vivo indicate the potential for indirect in vivo imaging of therapeutic gene expression in tumor tissue infected with any recombinant HSV-1 vector where a therapeutic gene is substituted for the lacZ gene.
The review presents investigations devoted to development of synthesis techniques and studying properties of nanosized single-domain ferrite spinels. Above-mentioned materials are used for: chemical ...fabrication of magnetosensitive nanocomposites with multilevel hierarchical nanoarchi-tecture and functions of recognition of microbiological objects in biologic media; targeted delivery of drugs into specific cells and organs and deposition; complex chemo-, immuno-, radiology neutron capture, hyperthermic, photodynamic cancer therapy and diagnostics in a real-time regime; adsorption of heavy-metal ions, toxins, cell decomposition debris and elimination of them from the body via the external magnetic field; development of a new generation of magnetosensitive adsorbents for medical, ecology, technical destination, composite nanostructured special materials, media and covers with beforehand set dielectric and magnetic losses to interact effectively with electromagnetic eradiation of super-high-frequency band.
Evidence for the decay X ( 3872 ) → J / ψ ω Poireau, V.; Hooberman, B.; Kerth, L. T. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
07/2010, Letnik:
82, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We present a study of the decays B^{0,+} --> J/psi pi^+ pi^- pi^0 K^{0,+}, using 467 10^6 BBbar pairs recorded with the BABAR detector. We present evidence for the decay mode X(3872) --> J/psi omega, ...with product branching fractions B(B^+ --> X(3872)K^+) B(X(3872) --> J/psi omega) =0.6\pm0.2\stat \pm 0.1\syst 10^{-5}, and B(B^0 --> X(3872)K^0) B(X(3872) --> J/psi omega) =0.6\pm0.3\stat \pm 0.1\syst 10^{-5}. A detailed study of the pi^+ pi^- pi^0 mass distribution from X(3872) decay favors a negative-parity assignment.
Using the entire sample of 467 × 10 6 Υ ( 4 S ) → B ¯¯¯ B decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory, we perform an ...analysis of B ± → D K ± decays, using decay modes in which the neutral D meson decays to either C P -eigenstates or non- C P -eigenstates. We measure the partial decay rate charge asymmetries for C P -even and C P -odd D final states to be A C P + = 0.25 ± 0.06 ± 0.02 and A C P − = − 0.09 ± 0.07 ± 0.02 , respectively, where the first error is the statistical and the second is the systematic uncertainty. The parameter A C P + is different from zero with a significance of 3.6 standard deviations, constituting evidence for direct C P violation. We also measure the ratios of the charged-averaged B partial decay rates in C P and non- C P decays, R C P + = 1.18 ± 0.09 ± 0.05 and R C P − = 1.07 ± 0.08 ± 0.04 . We infer frequentist confidence intervals for the angle γ of the unitarity triangle, for the strong phase difference δ B , and for the amplitude ratio r B , which are related to the B − → D K − decay amplitude by r B e i ( δ B − γ ) = A ( B − → ¯¯¯ D 0 K − ) / A ( B − → D 0 K − ) . Including statistical and systematic uncertainties, we obtain 0.24 < r B < 0.45 ( 0.06 < r B < 0.51 ) and, modulo 180°, 11.3 ° < γ < 22.7 ° or 80.8 ° < γ < 99.2 ° or 157.3 ° < γ < 168.7 ° ( 7.0 ° < γ < 173.0 ° ) at the 68% (95%) confidence level.
Terahertz light-driven coupling of antiferromagnetic spins to lattice Mashkovich, Evgeny A; Grishunin, Kirill A; Dubrovin, Roman M ...
Science (American Association for the Advancement of Science),
2021-Dec-24, 2021-12-24, 20211224, Letnik:
374, Številka:
6575
Journal Article
Recenzirano
Odprti dostop
Understanding spin-lattice coupling represents a key challenge in modern condensed matter physics, with crucial importance and implications for ultrafast and two-dimensional magnetism. The efficiency ...of angular momentum and energy transfer between spins and the lattice imposes fundamental speed limits on the ability to control spins in spintronics, magnonics, and magnetic data storage. We report on an efficient nonlinear mechanism of spin-lattice coupling driven by terahertz light pulses. A nearly single-cycle terahertz pulse resonantly interacts with a coherent magnonic state in the antiferromagnet cobalt difluoride (CoF
) and excites the Raman-active terahertz phonon. The results reveal the distinctive functionality of antiferromagnets that allows ultrafast spin-lattice coupling using light.
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