β-lapachone induces growth inhibition and apoptosis in bladder cancer cells by modulation of BCL-2 family and activation of caspases

Aim: To study in vitro the molecular mechanism of apoptosis caused by b-lapachone, a quinone obtained from the bark of the lapacho tree (Tabebuia avellanedae). Materials and Methods: The study was carried out on human bladder carcinoma T24 cell line. Determination of cell viability was done using trypan blue exclusion method, apoptosis quantitative estimation — by DAPI staining and agarose gel electrophoresis for DNA fragmentation. Flow cytometry analysis, RT-PCR and Western blot analysis, colorimetric assay of caspase activity were applied as well. Results: It was found that in micromolar range of concentrations b-lapachone inhibited the viability of T24 cells by inducing apoptosis, which could be proved by formation of apoptotic bodies and DNA fragmentation. Treatment of T24 cells with b-lapachone resulted in a down-regulation of Bcl-2 expression and up-regulation of Bax expression. b-lapachone-induced apoptosis was also associated with activation of caspase-3 and caspase-9, inhibition of IAP expression, and degradation of poly (ADP-ribose) polymerase, phospholipase C-g1 and b-catenin proteins. At the same time Fas and FasL levels were inhibited upon treatment with b-lapachone in a concentration-dependent manner. Conclusion: b-lapachone-induced apoptosis in T24 cells is mediated, at least in part, by the mitochondrial-signaling pathway.Цель: изучить механизмы апоптоза клеток карциномы мочевого пузыря человека Т24 при действии β-лапакона, хинона из коры дерева Tabebuia avellanedae. Материалы и методы: для определения жизнеспособности клеток использовали окраску трипановым синим; окрашивание DAPI и электрофоретический анализ фрагментации ДНК в агарозном геле, метод проточной цитометрии (для количественной оценки апоптоза); полимеразную цепную реакцию в режиме реального времени (РВ-ПЦР) и Вестерн блот-анализ (для оценки уровня экспрессии генов и белков), а также колориметрический анализ активности каспаз. Результаты: выявлено, что в микромолярных концентрациях β-лапакон понижает жизне- способность клеток линии Т24 путем активации апоптоза, что подтверждается формированием апоптотических тел и фрагментацией ДНК. Результаты РВ-ПЦР и иммуноблоттинга указывают на то, что обработка клеток β-лапаконом приводит к снижению экспрессии Bcl-2 и к активации Bax. Апоптоз, индуцированный β-лапаконом, также сопровож- дается активацией каспаз -3­­ и -9, ингибированием экспрессии семейства IAP, а также деградацией поли-(ADP-рибозо) полимеразы, фосфатазы C-γ1 и β-катенина. Тем не менее, уровень экспрессии Fas и FasL снижался при увеличении концентрации β-лапакона. Выводы: апоптоз, индуцированный при действии β-лапакона в клетках Т24, может быть час- тично опосредован митохондриальным сигнальным каскадом

Gate errors in solid state quantum computer architectures

We theoretically consider possible errors in solid state quantum computation due to the interplay of the complex solid state environment and gate imperfections. In particular, we study two examples of gate operations in the opposite ends of the gate speed spectrum, an adiabatic gate operation in electron-spin-based quantum dot quantum computation and a sudden gate operation in Cooper pair box superconducting quantum computation. We evaluate quantitatively the non-adiabatic operation of a two-qubit gate in a two-electron double quantum dot. We also analyze the non-sudden pulse gate in a Cooper-pair-box-based quantum computer model. In both cases our numerical results show strong influences of the higher excited states of the system on the gate operation, clearly demonstrating the importance of a detailed understanding of the relevant Hilbert space structure on the quantum computer operations.Comment: 6 pages, 2 figure

Theoretical study of electronic Raman scattering of Borocarbide superconductors

The electronic Raman scattering of Borocarbide superconductors is studied based on the weak coupling theory with $s+g$-wave gap symmetry. The low energy behaviors and the relative peak positions can be naturally understood, while the explanation of the detailed shape of the $B_{1g}$ peak seems to require a strong inelastic interaction not present in the weak coupling theory.Comment: Revtex 4 file, 9 pages and 5 figure

Neutral Higgs sector of the next-to-minimal supersymmetric standard model with explicit CP violation

The neutral Higgs sector of the next-to-minimal supersymmetric standard model (NMSSM) with explicit CP violation is investigated at the 1-loop level, using the effective potential method; not only the loops involving the third generation of quarks and scalar quarks, but also the loops involving $W$ boson, charged Higgs boson, and chargino are taken into account. It is found that for some parameter values of the NMSSM the contributions from the $W$ boson, charged Higgs boson, and chargino loops may modify the masses of the neutral Higgs bosons and the mixings among them significantly, depending on the CP phase. In $e^+e^-$ collisions, the prospects for discovering neutral Higgs bosons are investigated within the context of the NMSSM with explicit CP violation when the dominant component of the lightest neutral Higgs boson is the Higgs singlet field of the NMSSM.Comment: Latex, 23 pages, 6 figure

Density functional method for nonequilibrium electron transport

We describe an ab initio method for calculating the electronic structure, electronic transport, and forces acting on the atoms, for atomic scale systems connected to semi-infinite electrodes and with an applied voltage bias. Our method is based on the density functional theory (DFT) as implemented in the well tested Siesta approach (which uses non-local norm-conserving pseudopotentials to describe the effect of the core electrons, and linear combination of finite-range numerical atomic orbitals to describe the valence states). We fully deal with the atomistic structure of the whole system, treating both the contact and the electrodes on the same footing. The effect of the finite bias (including selfconsistency and the solution of the electrostatic problem) is taken into account using nonequilibrium Green's functions. We relate the nonequilibrium Green's function expressions to the more transparent scheme involving the scattering states. As an illustration, the method is applied to three systems where we are able to compare our results to earlier ab initio DFT calculations or experiments, and we point out differences between this method and existing schemes. The systems considered are: (1) single atom carbon wires connected to aluminum electrodes with extended or finite cross section, (2) single atom gold wires, and finally (3) large carbon nanotube systems with point defects.Comment: 18 pages, 23 figure

Electroweak Symmetry Breaking at the LHC

One of the major goals of the Large Hadron Collider is to probe the electroweak symmetry breaking mechanism and the generation of the masses of the elementary particles. We review the physics of the Higgs sector in the Standard Model and some of its extensions such as supersymmetric theories and models of extra dimensions. The prospects for discovering the Higgs particles at the LHC and the study of their fundamental properties are summarised.Comment: 27 pages, 45 figures, uses LaTeX (insa.sty). Invited review for volume on LHC physics to celebrate the Platinum Jubilee of the Indian National Science Academy, edited by Amitava Datta, Biswarup Mukhopadhyaya and Amitava Raychaudhuri. Expanded the acronym in the title in the annoncement. No other change in the text or reference

Quantum Interference in Superconducting Wire Networks and Josephson Junction Arrays: Analytical Approach based on Multiple-Loop Aharonov-Bohm Feynman Path-Integrals

We investigate analytically and numerically the mean-field superconducting-normal phase boundaries of two-dimensional superconducting wire networks and Josephson junction arrays immersed in a transverse magnetic field. The geometries we consider include square, honeycomb, triangular, and kagome' lattices. Our approach is based on an analytical study of multiple-loop Aharonov-Bohm effects: the quantum interference between different electron closed paths where each one of them encloses a net magnetic flux. Specifically, we compute exactly the sums of magnetic phase factors, i.e., the lattice path integrals, on all closed lattice paths of different lengths. A very large number, e.g., up to $10^{81}$ for the square lattice, exact lattice path integrals are obtained. Analytic results of these lattice path integrals then enable us to obtain the resistive transition temperature as a continuous function of the field. In particular, we can analyze measurable effects on the superconducting transition temperature, $T_c(B)$, as a function of the magnetic filed $B$, originating from electron trajectories over loops of various lengths. In addition to systematically deriving previously observed features, and understanding the physical origin of the dips in $T_c(B)$ as a result of multiple-loop quantum interference effects, we also find novel results. In particular, we explicitly derive the self-similarity in the phase diagram of square networks. Our approach allows us to analyze the complex structure present in the phase boundaries from the viewpoint of quantum interference effects due to the electron motion on the underlying lattices.Comment: 18 PRB-type pages, plus 8 large figure

Many body physics from a quantum information perspective

The quantum information approach to many body physics has been very successful in giving new insight and novel numerical methods. In these lecture notes we take a vertical view of the subject, starting from general concepts and at each step delving into applications or consequences of a particular topic. We first review some general quantum information concepts like entanglement and entanglement measures, which leads us to entanglement area laws. We then continue with one of the most famous examples of area-law abiding states: matrix product states, and tensor product states in general. Of these, we choose one example (classical superposition states) to introduce recent developments on a novel quantum many body approach: quantum kinetic Ising models. We conclude with a brief outlook of the field.Comment: Lectures from the Les Houches School on "Modern theories of correlated electron systems". Improved version new references adde

Low energy fast events from radon progenies at the surface of a CsI(Tl) scintillator

In searches for rare phenomena such as elastic scattering of dark matter particles or neutrinoless double beta decay, alpha decays of Rn222 progenies attached to the surfaces of the detection material have been identified as a serious source of background. In measurements with CsI(Tl) scintillator crystals, we demonstrate that alpha decays of surface contaminants produce fast signals with a characteristic mean-time distribution that is distinct from those of neutron- and gamma-induced events.Comment: 9 pages, 8 figure

Predicting stroke through genetic risk functions: the CHARGE Risk Score Project.

BACKGROUND AND PURPOSE: Beyond the Framingham Stroke Risk Score, prediction of future stroke may improve with a genetic risk score (GRS) based on single-nucleotide polymorphisms associated with stroke and its risk factors. METHODS: The study includes 4 population-based cohorts with 2047 first incident strokes from 22,720 initially stroke-free European origin participants aged ≥55 years, who were followed for up to 20 years. GRSs were constructed with 324 single-nucleotide polymorphisms implicated in stroke and 9 risk factors. The association of the GRS to first incident stroke was tested using Cox regression; the GRS predictive properties were assessed with area under the curve statistics comparing the GRS with age and sex, Framingham Stroke Risk Score models, and reclassification statistics. These analyses were performed per cohort and in a meta-analysis of pooled data. Replication was sought in a case-control study of ischemic stroke. RESULTS: In the meta-analysis, adding the GRS to the Framingham Stroke Risk Score, age and sex model resulted in a significant improvement in discrimination (all stroke: Δjoint area under the curve=0.016, P=2.3×10(-6); ischemic stroke: Δjoint area under the curve=0.021, P=3.7×10(-7)), although the overall area under the curve remained low. In all the studies, there was a highly significantly improved net reclassification index (P<10(-4)). CONCLUSIONS: The single-nucleotide polymorphisms associated with stroke and its risk factors result only in a small improvement in prediction of future stroke compared with the classical epidemiological risk factors for stroke