Hyperbolic chaos in the klystron-type microwave vacuum tube oscillator.

The ring-loop oscillator consisting of two coupled klystrons which is capable of generating hyperbolic chaotic signal in the microwave band is considered. The system of delayed-differential equations describing the dynamics of the oscillator is derived. This system is further reduced to the two-dimensional return map under the assumption of the instantaneous build-up of oscillations in the cavities.

Measuring tumor aggressiveness and targeting metastatic lesions with fluorescent pHLIP.

Purpose: Malignant cancer foci develop acidic extracellular environments. Mild acidic conditions trigger insertion and folding of the pH (low) insertion peptide (pHLIP(TM)) across a cellular membrane, enabling targeting of such lesions.

Procedures: We employed optical imaging to follow targeting by fluorescent pHLIP given i.

Functional analysis of human BRCA2 variants using a mouse embryonic stem cell-based assay.

We describe here a comprehensive and reliable assay to test the functional significance of variants of unknown clinical significance (VUS) identified in the human breast cancer susceptibility gene, BRCA2. The assay is based on the ability of human BRCA2 to complement the loss of endogenous Brca2 in mouse embryonic stem cells. The procedure involves generation of a desired mutation in BRCA2 present in a bacterial artificial chromosome (BAC) and the introduction of the BAC into ES cells engineered for the assay.

Nanosensing of Fcγ receptors on macrophages.

Determining the distribution of specific binding sites on biological samples with high spatial accuracy (in the order of several nanometer) is an important challenge in many fields of biological science. Combination of high-resolution atomic force microscope (AFM) topography imaging with single-molecule force spectroscopy provides a unique possibility for the detection of specific molecular recognition events. The identification and localization of specific receptor binding sites on complex heterogeneous biosurfaces such as cells and membranes are of particular interest in this context.

In vivo bone formation by progeny of human embryonic stem cells.

The derivation of osteogenic cells from human embryonic stem cells (hESCs) or from induced pluripotent stem cells for bone regeneration would be a welcome alternative to the use of adult stem cells. In an attempt to promote hESC osteogenic differentiation, cells of the HSF-6 line were cultured in differentiating conditions in vitro for prolonged periods of time ranging from 7 to 14.5 weeks, followed by in vivo transplantation into immunocompromised mice in conjunction with hydroxyapatite/tricalcium phosphate ceramic powder.

Initial receptor-ligand interactions modulate gene expression and phagosomal properties during both early and late stages of phagocytosis.

The receptors engaged during recognition and phagocytic uptake of microorganisms and particles influence signaling events and diverse subcellular responses that occur during phagosome formation and maturation. However, pathogens generally have multiple ligands on their surface, making it difficult to dissect the roles of individual receptors during phagocytosis. Moreover, it remains elusive to which extent receptor-ligand interactions and early binding events define the subsequent intracellular fate of phagosomes.

[Effect of neurogenic inactivity on posttetanic responses of rat fast muscle].

At a short-term tetanic stimulation of fast muscle in response to subsequent single stimulation there is recorded a temporary increase of the strength of single contractions that returns to the initial background after 6--10 min. This phenomenon is called posttetanic potentiation (PTP) and is recorded only in fast muscles. The goal of the present work was a study of effect of motor innervation on the course of PTP in rat m.

Distinct roles of myosin Va in membrane remodeling and exocytosis of secretory granules.

Hormone- and neuropeptide-containing secretory granules (SGs) of neuroendocrine PC12 cells are formed at the trans- Golgi network as immature SGs. These intermediates are converted to mature SGs in a complex maturation process, including matrix condensation, processing of cargo proteins and removal of proteins and membrane in clathrin-coated vesicles. The resulting mature SGs undergo Ca2+-dependent exocytosis upon an appropriate stimulus.

[Primary generalized amyloidosis with restrictive cardiomyopathy and severe chronic cardiac insufficiency].

The paper reports a case of restrictive cardiomyopathy due to cardiac amyloidosis. Diagnosis of this condition encounters difficulty created by the absence of pathognomonic symptoms of the disease. Major manifestations of amyloid cardiomyopathy are refractive chronic cardiac insufficiency, absence of cardiomyalgia, marked deterioration of diastolic filling of both ventricles, systemic hypotension, and disturbed heart rhythms.

Novel derivatives of 1,3,4-oxadiazoles are potent mitostatic agents featuring strong microtubule depolymerizing activity in the sea urchin embryo and cell culture assays.

A series of novel 1,3,4-oxadiazole derivatives based on structural and electronic overlap with combretastatins have been designed and synthesized. Initially, we tested all new compounds in vivo using the phenotypic sea urchin embryo assay to yield a number of agents with anti-proliferative, anti-mitotic, and microtubule destabilizing activities. The experimental data led to identification of 1,3,4-oxadiazole derivatives with isothiazole (5-8) and phenyl (9-12) pharmacophores featuring activity profiles comparable to that of combretastatins, podophyllotoxin and nocodazole.

[About mechanisms of genesis, structure, and functional role of endogenous rhythms (to the 100-anniversary of Aleksei Valentinovich Voino-Yasenetskii)].

The work presents a short review of concepts of origin and representation of ancient (primary) endogenous rhythms whose period is in the near-second-near-minute range. These rhythms are the basis for the appearance of the viscero- and somatomotor excitation in various functional systems of vertebrate and invertebrate animals. Based on literature data and the own studies, there has been considered a hypothesis of universality of mechanisms of generation of endogenous rhythms of a certain frequency diapason regardless of their localization.

Immunohistochemical characteristics of the hypophysis in normal conditions and chronic stress.

Quantitative immunohistochemical methods were used to assess activation of the hypothalamo-hypophyseal-adrenocortical system at the level of its central component - the adenohypophysis - in the growing body during chronic exposure to psychoemotional stressors of different strengths. Sprague-Dawley rats aged 30 days were subjected to "mild" or "severe" immobilization stress for 5 h per day for seven days. Animals were decapitated at the end of the last stress session and the endocrine glands (hypophysis, adrenals) were harvested, weighed, and embedded in paraffin; sections were stained with hematoxylin and eosin, and also immunohistochemically using monoclonal antibodies to adrenocorticotropic hormone (ACTH) and proliferating cell nuclear antigen (PCNA) following by automated image analysis.

Functional redundancy of exon 12 of BRCA2 revealed by a comprehensive analysis of the c.6853A>G (p.I2285V) variant.

Variants of unknown significance (VUS) in BRCA1 and BRCA2 are common, and present significant challenges for genetic counseling. We observed that BRCA2: c.6853A>G (p.

X-ray nanointerferometer based on si refractive bilenses.

We report a novel type of x-ray interferometer employing a bilens system consisting of two parallel compound refractive lenses, each of which creates a diffraction limited beam under coherent illumination. By closely overlapping such coherent beams, an interference field with a fringe spacing ranging from tens of nanometers to tens of micrometers is produced. In an experiment performed with 12 keV x rays, submicron fringes were observed by scanning and moiré imaging of the test grid.

Cell Regulation of Proliferation and Differentiation ex vivo for Cells Containing Ph Chromosome in Chronic Myeloid Leukemia.

Cell regulation of Ph(+)cell proliferation and differentiation has been studied ex vivo in various chronic myeloid leukemia (CML) patients. The regulation is provided by alternation of effective stages of proliferation and maturation with inhibition of Ph(+) cell proliferation by accumulating neutrophils under apoptosis blockage. The alternation of stages consists of switching stage 1 (effective proliferation) to stage 2 (effective maturation) and proceeds according to the 1/2 -1/2/1 or 2/1-2/1/2/1 schemes.

[Contractile properties of fibers and cytoskeletal proteins of gerbil's hindlimb muscles after space flight].

The work had the goal to compare the microgravity effects on gerbil's muscles-antagonists, m. soleus and m. tibialis anterior.

[Dasatinib treatment of imatinib-resistant and imatinib-intolerant patients with chronic myeloid leukemia in a chronic phase].

Aim: To analyse resistance to imatinib therapy, efficacy and safety of dasatinib.

Material And Methods: A total of 18 patients with chronic myeloid leukemia (CML) in a chronic stage received dasatinib for 9-30 months (median 30 months) to September 2008.

Results: Lethal outcomes during dasatinib treatment were absent.

Violation of hyperbolicity in a diffusive medium with local hyperbolic attractor.

Departing from a system of two nonautonomous amplitude equations, demonstrating hyperbolic chaotic dynamics, we construct a one-dimensional medium as an ensemble of such local elements introducing spatial coupling via diffusion. When length of the medium is small, all spatial cells oscillate synchronously, reproducing the local hyperbolic dynamics. This regime is characterized by a single positive Lyapunov exponent.

Regular and anomalous extraordinary optical transmission at the THz-gap.

In this paper Anomalous Extraordinary Transmission (ET) is reported for s-polarization of low loss doubly periodic subwavelength hole arrays patterned on polypropylene (PP) substrates by conventional contact photolithography at the so-called THz-gap (1-10 THz). The unexpected enhanced transmittance for s-polarization (i.e.

[T-channels and Na+,Ca2+-exchangers as components of the Ca2+-system of the myocardial activity regulation of the frog Rana temporaria].

Earlier we have shown that regulation of rhythm and strength of the frog heart contractions, mediated by transmitters of the autonomic nervous system, is of the Ca2+-character. In the present work, we studied chrono- and inotropic effect of verapamil--an inhibitor of Ca2+-channels of the L-type, of nickel chloride--an inhibitor of Ca2+-channels of the T-type, and of Na+,Ca2+-exchangers as well as of adrenaline and acetylcholine (ACh) after nickel chloride. It has been found that the intracardially administered NiCl2 at a dose of 0.