Genetic markers in neuroblastoma

Neuroblastoma is one of the most frequent solid pediatric tumors. Its clinical course and response to treatment are both markedly heterogenic. Such a varied spectrum demands genomic hallmarks to be established for the sake of identifying the molecular mechanisms, which initiate the tumor and lead to malignant progression. The contemporary biological and genetic revelations regarding neuroblastoma are a crucial part of determining the diagnosis, stratifying the risk, and developing new treatment strategies. Such systems of risk assessment appraise clinical, histopathological, and genetic variables. Among them are classifiers of gene expression, changes in the number of copies and somatic mutation models, chromosomal aberrations. Different studies suggest new prognostic markers, including gene signatures, telomerase activity, as well as epigenetic markers. Contemporary studies have contributed the means of molecular characterization of blood and tumor samples, among which high-yield technologies for analysis of DNA, microRNA, and other non-coding RNAs.Neuroblastoma is one of the most frequent solid pediatric tumors. Its clinical course and response to treatment are both markedly heterogenic. Such a varied spectrum demands genomic hallmarks to be established for the sake of identifying the molecular mechanisms, which initiate the tumor and lead to malignant progression. The contemporary biological and genetic revelations regarding neuroblastoma are a crucial part of determining the diagnosis, stratifying the risk, and developing new treatment strategies. Such systems of risk assessment appraise clinical, histopathological, and genetic variables. Among them are classifiers of gene expression, changes in the number of copies and somatic mutation models, chromosomal aberrations. Different studies suggest new prognostic markers, including gene signatures, telomerase activity, as well as epigenetic markers. Contemporary studies have contributed the means of molecular characterization of blood and tumor samples, among which high-yield technologies for analysis of DNA, microRNA, and other non-coding RNAs

Review of cyanotoxicity studies based on cell cultures

Cyanotoxins (CTs) are a large and diverse group of toxins produced by the peculiar photosynthetic prokaryotes of the domain Cyanoprokaryota. Toxin-producing aquatic cyanoprokaryotes can develop in mass, causing “water blooms” or “cyanoblooms,” which may lead to environmental disaster—water poisoning, extinction of aquatic life, and even to human death. CT studies on single cells and cells in culture are an important stage of toxicological studies with increasing impact for their further use for scientific and clinical purposes, and for policies of environmental protection. The higher cost of animal use and continuous resistance to the use of animals for scientific and toxicological studies lead to a progressive increase of cell lines use. This review aims to present (1) the important results of the effects of CT on human and animal cell lines, (2) the methods and concentrations used to obtain these results, (3) the studied cell lines and their tissues of origin, and (4) the intracellular targets of CT. CTs reviewed are presented in alphabetical order as follows: aeruginosins, anatoxins, BMAA (β-N-methylamino-L-alanine), cylindrospermopsins, depsipeptides, lipopolysaccharides, lyngbyatoxins, microcystins, nodularins, cyanobacterial retinoids, and saxitoxins. The presence of all these data in a review allows in one look to advance the research on CT using cell cultures by facilitating the selection of the most appropriate methods, conditions, and cell lines for future toxicological, pharmacological, and physiological studies

Breast ultrasound tomography . Novel solutions

Ракът на гърдата според последни проучвания е първото по честота онкологично заболяване при жени в целия свят, както и второто по смъртност за същия пол след белодробния рак. Отбелязвайки спад в честотата на новите случаи в Щатите в годините след 2000-2002 (частично в следствие на редуцираното приложе- ние на хормон-заместителната терапия), ракът на гърдата остава заболяване с огромна социална значимост. Съответно от особена важ- ност са методите за скрининг и диагностика. Диагностичният арсенал нараства с всяка изминала година - от стандартната и дигитална мамография еволюира мамографската томосинтеза, a от ехоскопичното изследване произли- зат два нови томографски метода, напълно лишени от йонизираща радиация, но предоставящи образи с висока информативност. Те биват съответно ехоскопия на цяла гърда (Whole Breast Ultrasound - WBU) и ултразвукова компютърна томография (Ultrasound Computed Tomography - USCT). Първият метод предоставя възможност за идентификация на малки ранни лезии в гърди с висока плътност - находки, трудни за идентификация дори с дигитална мамография. Състои се от апликатор с автоматично движещ се трансдюсер, целящ покриване на цялата тъкан на гърдата и прилежащите зони на интерес - съществуват две технологични разновидности на апликатора. И при двата лаборант асистира за адекватна компресия. Вторият метод не налага компресия - гърдата се поставя в съд с вода, по стените на който са разположени многобройни трансдюсери, добиващи изображения. Последните се реконструират от компютър както при рентгеновата компютърна томография. Стандартните ултразвукови изображения на практика са томографски - без наслагване на съседни структури, но са добити от един-единствен ъгъл. При USCT образът на всеки обект се добива от десетки ъгли, подобрявайки визуализацията.According to recent studies, breast cancer is the oncological disease of highest incidence in women worldwide, as well as the second-highest after pulmonary cancer mortality-wize. Noting a decrease in incidence in the USA in the years after 2000-2002 (partial- ly due to receding use of hormone replacement therapy), breast cancer remains a condition of tremendous social significance. Therefore, special attention is to be given to the methods of screening and diagnostics. The diagnostic arsenal is augmented more and more each year - from analogue and digital mammography stems digital mammographic tomosynthesis, while ultrasonography evolves into two new methods capable of delivering images of high informativeness - also devoid of ionizing radiation. These methods are Whole Breast Ultrasound (WBU) and Ultrasound Computed Tomography (USCT). WBU allows for identification of small early lesions in dense breast tissue - difficult to identify even on digital mammography. It consists of an automatically propelled transducer, which thoroughly scans the breast and adherent zones of interest. Two technological variants of the method exist. Both require a technologist to assist with adequate compression. USCT, on the other hand, does not require compression - the breast is put into a vessel of water, the walls of which are made up of multiple transducers, all yielding images. These images are then reformatted by a computer like in Röntgen-ray CT. Technically, standard ultrasound images are tomographic - no overlap of adjacent structures is present. However, they are yielded from a single angle at a time. USCT images each object from a multitude of angles, improving visualization

Gluon condensates and c, b quark masses from quarkonia ratios of moments

We extract (for the first time) the ratio of the gluon condensate < g^3f_{abc}G^3 >/ expressed in terms of the liquid instanton radius rho_c from charmonium moments sum rules by examining the effects of < alpha_s G^2 > in the determinations of both rho_c and the running MS mass m_c(m_c). Using a global analysis of selected ratios of moments at different Q^2=0, 4m_c^2 and 8m_c^2 and taking from 0.06 GeV^4, where the estimate of rho_c is almost independent of , we deduce: rho_c=0.98(21) GeV^{-1} which corresponds to = (31+- 13) GeV^2 . The value of m_c(m_c) is less affected (within the errors) by the variation of , where a common solution from different moments are reached for greater than 0.02 GeV^4. Using the values of =0.06(2) GeV^4 from some other channels and the previous value of , we deduce: m_c(m_c)=1260(18) MeV and m_b(m_b)=4173(10) MeV, where an estimate of the 4-loops contribution has been included. Our analysis indicates that the errors in the determinations of the charm quark mass without taking into account the ones of the gluon condensates have been underestimated. To that accuracy, one can deduce the running light and heavy quark masses and their ratios evaluated at M_Z, where it is remarkable to notice the approximate equalities: m_s/m_u= m_b/m_s= m_t/m_b= 51(4), which might reveal some eventual underlying novel symmetry of the quark mass matrix in some Grand Unified Theories.Comment: 8 pages, 2 figures, 5 tables. Due to a bug in the program, values of m_b(m_b) in Table 5 have been changed and are in excellent agreement with the ones from Q^2-moments (arXiv:1105.2922[hep-ph]) and exponential sum rules (arXiv:1105.5070[hep-ph]) within stability criteria. These changes will be published as an erratum in PL

Hadrons with Charm and Beauty

By combining potential models and QCD spectral sum rules (QSSR), we discuss the spectroscopy of the $(b\bar c)$ mesons and of the $(bcq)$, $(ccq)$ and $(bbq)$ baryons (${q}\equiv {d}$ or $s$), the decay constant and the (semi)leptonic decay modes of the $B_c$ meson. For the masses, the best predictions come from potential models and read: $M_{B_c} = (6255 \pm 20)$~MeV, $M_{B^*_c} = (6330 \pm 20)$~MeV, $M_{\Lambda(bcu)} = (6.93\pm 0.05)$~GeV, $M_{\Omega(bcs)} = (7.00\pm 0.05)$~GeV, $M_{\Xi^*(ccu)} =(3.63\pm 0.05)$~GeV and $M_{\Xi^*(bbu)} = (10.21\pm 0.05)$~GeV. The decay constant $f_{B_c} = (2.94 \pm 0.21) f_\pi$ is well determined from QSSR and leads to: $\Gamma(B_c \rightarrow \nu_\tau \tau) = (3.0 \pm 0.4)( V_{cb}/0.037 )^2$ $\times 10^{10}$ s$^{-1}$.The uses of the vertex sum rules for the semileptonic decays of the $B_c$ show that the $t$-dependence of the form factors is much stronger than predicted by vector meson dominance. It also predicts the almost equal strength of about 0.30 $\times 10^{10}$ sec$^{-1}$ for the semileptonic rates $B_c$ into $B_s, B^*_s,\eta_c$ and J/$\psi$. Besides these phenomenological results, we also show explicitly how the Wilson coefficients of the $\langle\alpha_s G^2\rangle$ and $\langle G^3\rangle$ gluon condensates already contain the full heavy quark- ($\langle\bar QQ\rangle$) and mixed- ($\langle\bar QGQ\rangle$) condensate contributions in the OPE.}Comment: 32 pages, LaTeX, no changes in the 1994 paper, latex errors corrected in 201

Operator Product Expansion and Quark-Hadron Duality: Facts and Riddles

We review the status of the practical operator product expansion (OPE), when applied to two-point correlators of QCD currents which interpolate to mesonic resonances, in view of the violations of local quark-hadron duality. Covered topics are: a mini-review of mesonic QCD sum rules in vacuum, at finite temperature, or at finite baryon density, a comparison of model calculations of current-current correlation functions in 2D and 4D with the OPE expression, a discussion of meson distribution amplitudes in the light of nonperturbatively nonlocal modifications of the OPE, and a reorganization of the OPE which (partially) resums powers of covariant derivatives.Comment: now 68 pages, 29 figures (1 figure added), habilitation thesis, mild restructuring, typos corrected, about 30 references and corresponding text added, version to be published in Prog. Part. Nucl. Phy

Global Study of Nuclear Structure Functions

We present the results of a phenomenological study of unpolarized nuclear structure functions for a wide kinematical region of x and Q^2. As a basis of our phenomenology we develop a model which takes into account a number of different nuclear effects including nuclear shadowing, Fermi motion and binding, nuclear pion excess and off-shell correction to bound nucleon structure functions. Within this approach we perform a statistical analysis of available data on the ratio of the nuclear structure functions F_2 for different nuclei in the range from the deuteron to the lead. We express the off-shell effect and the effective scattering amplitude describing nuclear shadowing in terms of few parameters which are common to all nuclei and have a clear physical interpretation. The parameters are then extracted from statistical analysis of data. As a result, we obtain an excellent overall agreement between our calculations and data in the entire kinematical region of x and Q^2. We discuss a number of applications of our model which include the calculation of the deuteron structure functions, nuclear valence and sea quark distributions and nuclear structure functions for neutrino charged-current scattering.Comment: 67 pages, 18 figures (v3: updated text and references, a new section with discussion about relation between off-shell effect and modification of the nucleon size in nuclei, accepted for publication in Nucl. Phys. A

Nonforward Parton Distributions

Applications of perturbative QCD to deeply virtual Compton scattering and hard exclusive electroproduction processes require a generalization of usual parton distributions for the case when long-distance information is accumulated in nonforward matrix elements of quark and gluon light-cone operators. We describe two types of nonperturbative functions parametrizing such matrix elements: double distributions F(x,y;t) and nonforward distribution functions F_\zeta (X;t), discuss their spectral properties, evolution equations which they satisfy, basic uses and general aspects of factorization for hard exclusive processes.Comment: Final version, to be published in Phys.Rev.

Unraveling hadron structure with generalized parton distributions

The generalized parton distributions, introduced nearly a decade ago, have emerged as a universal tool to describe hadrons in terms of quark and gluonic degrees of freedom. They combine the features of form factors, parton densities and distribution amplitudes--the functions used for a long time in studies of hadronic structure. Generalized parton distributions are analogous to the phase-space Wigner quasi-probability function of non-relativistic quantum mechanics which encodes full information on a quantum-mechanical system. We give an extensive review of main achievements in the development of this formalism. We discuss physical interpretation and basic properties of generalized parton distributions, their modeling and QCD evolution in the leading and next-to-leading orders. We describe how these functions enter a wide class of exclusive reactions, such as electro- and photo-production of photons, lepton pairs, or mesons. The theory of these processes requires and implies full control over diverse corrections and thus we outline the progress in handling higher-order and higher-twist effects. We catalogue corresponding results and present diverse techniques for their derivations. Subsequently, we address observables that are sensitive to different characteristics of the nucleon structure in terms of generalized parton distributions. The ultimate goal of the GPD approach is to provide a three-dimensional spatial picture of the nucleon, direct measurement of the quark orbital angular momentum, and various inter- and multi-parton correlations.Comment: 370 pages, 62 figures; Dedicated to Anatoly V. Efremov on occasion of his 70th anniversar

Estudio de viabilidad sobre la transformación de un motor de encendido provocado para su funcionamiento a GLP

Bachvarov, GN. (2011). Estudio de viabilidad sobre la transformación de un motor de encendido provocado para su funcionamiento a GLP. http://hdl.handle.net/10251/15123.Archivo delegad