Uncoupling of oxidative phosphorylation and antioxidants affect fusion of primary human myoblasts in vitro

Reactive oxygen species are at the origin of muscular fatigue and atrophy. They are also linked to muscular dystrophies, a group of human genetic diseases. Several studies point to the benefits of application of antioxidants and uncouplers of oxidative phosphorylation to improve the functional activity of normal and pathological muscles. Other studies point to potential dangers of these compounds. Aim. To study the effect of mitochondria-targeted antioxidants and uncouplers of oxidative phosphorylation on muscle differentiation. Methods. Muscle differentiation was induced by serum starvation and monitored by troponin T staining. Results. the mitochondria-targeted uncoupler of oxidative phosphorylation C12TPP, but not the mitochondria-targeted antioxidant SkQ1, inhibit fusion of primary myoblasts upon their differentiation, but do not affect the synthesis of troponin T, a protein marker of muscle differentiation. Conclusion. The effect of C12TPP could be at least partially mediated by inhibition of reactive oxygen species (ROS) production since antioxidant N-acetylcysteine at high doses also inhibited differentiation of myoblasts.Активні форми кисню (АФК) можуть викликати м'язову втому і атрофію м'язів. АФК також пов'язані з м'язовими дистрофії. Безліч досліджень вказує на позитивний вплив антиоксидантів і разобщітелей окисного фосфорилювання на функціональну активність м'язів в нормі та патології. Мета. Вивчити вплив мітохондріальної-спрямованих антиоксидантів і разобщітелей окисного фосфорилювання на диференціювання первинних міобластів людини. Методи. Результати. мітохондріальної-спрямований разобщитель окисного фосфорилювання C12TPP, але не мітохондріальної-спрямований антиоксидант SkQ1, пригнічує злиття міобластів при диференціюванні, при цьому не впливаючи на експресію тропонина Т, білкового маркера м'язової диференціювання. Висновки. Вплив C12TPP може бути частково викликано пригніченням АФК, так як високі концентрації класичного антиоксиданту N-ацетилцистеїну також інгібували диференціювання міобластів людини.Активные формы кислорода (АФК) могут вызывать мышечную усталость и атрофию мышц. АФК также связаны с мышечными дистрофиями. Множество исследований указывает на положительное влияние антиоксидантов и разобщителей окислительного фосфорилирования на функциональную активность мышц в норме и патологии. Цель. Изучить влияние митохондриально-направленных антиоксидантов и разобщителей окислительного фосфорилирования на дифференцировку первичных миобластов человека. Методы. Результаты. митохондриально-направленный разобщитель окислительного фосфорилирования C12TPP, но не митохондриально-направленный антиоксидант SkQ1, ингибирует слияние миобластов при дифференцировке, при этом не влияя на экспрессию тропонина Т, белкового маркера мышечной дифференцировки. Выводы. Влияние C12TPP может быть частично вызвано ингибированием АФК, так как высокие концентрации классического антиоксиданта N-ацетилцистеина также ингибировали дифференцировку миобластов человека

Applicability of perturbative QCD to Λb→Λc\Lambda_b \to \Lambda_c decays

We develop perturbative QCD factorization theorem for the semileptonic heavy baryon decay $\Lambda_b \to \Lambda_c l\bar{\nu}$, whose form factors are expressed as the convolutions of hard $b$ quark decay amplitudes with universal $\Lambda_b$ and $\Lambda_c$ baryon wave functions. Large logarithmic corrections are organized to all orders by the Sudakov resummation, which renders perturbative expansions more reliable. It is observed that perturbative QCD is applicable to $\Lambda_b \to \Lambda_c$ decays for velocity transfer greater than 1.2. Under requirement of heavy quark symmetry, we predict the branching ratio $B(\Lambda_b \to \Lambda_c l{\bar\nu})\sim 2$, and determine the $\Lambda_b$ and $\Lambda_c$ baryon wave functions.Comment: 12 pages in Latex file, 3 figures in postscript files, some results are changed, but the conclusion is the sam

Rare Decays of \Lambda_b->\Lambda + \gamma and \Lambda_b ->\Lambda + l^{+} l^{-} in the Light-cone Sum Rules

Within the Standard Model, we investigate the weak decays of $\Lambda_b \to \Lambda + \gamma$ and $\Lambda_b \to \Lambda + l^{+} l^{-}$ with the light-cone sum rules approach. The higher twist distribution amplitudes of $\Lambda$ baryon to the leading conformal spin are included in the sum rules for transition form factors. Our results indicate that the higher twist distribution amplitudes almost have no influences on the transition form factors retaining the heavy quark spin symmetry, while such corrections can result in significant impacts on the form factors breaking the heavy quark spin symmetry. Two phenomenological models (COZ and FZOZ) for the wave function of $\Lambda$ baryon are also employed in the sum rules for a comparison, which can give rise to the form factors approximately 5 times larger than that in terms of conformal expansion. Utilizing the form factors calculated in LCSR, we then perform a careful study on the decay rate, polarization asymmetry and forward-backward asymmetry, with respect to the decays of $\Lambda_b \to \Lambda \gamma$, $\Lambda l^{+}l^{-}$.Comment: 38 pages, 15 figures, some typos are corrected and more references are adde

Exclusive semileptonic rare decays B−>(B ->_ (K,K^*) \ell^+ \ell^- in supersymmetric theories

The invariant mass spectrum, forward-backward asymmetry, and lepton polarizations of the exclusive processes $B\to K(K^*)\ell^+ \ell^-, \ell=\mu, \tau$ are analyzed under supersymmetric context. Special attention is paid to the effects of neutral Higgs bosons (NHBs). Our analysis shows that the branching ratio of the process \bkm can be quite largely modified by the effects of neutral Higgs bosons and the forward-backward asymmetry would not vanish. For the process \bksm, the lepton transverse polarization is quite sensitive to the effects of NHBs, while the invariant mass spectrum, forward-backward asymmetry, and lepton longitudinal polarization are not. For both \bkt and \bkst, the effects of NHBs are quite significant. The partial decay widths of these processes are also analyzed, and our analysis manifest that even taking into account the theoretical uncertainties in calculating weak form factors, the effects of NHBs could make SUSY shown up.Comment: Several references are added, typo are correcte

Charmless Exclusive Baryonic B Decays

We present a systematical study of two-body and three-body charmless baryonic B decays. Branching ratios for two-body modes are in general very small, typically less than $10^{-6}$, except that \B(B^-\to p \bar\Delta^{--})\sim 1\times 10^{-6}. In general, $\bar B\to N\bar\Delta>\bar B\to N\bar N$ due to the large coupling constant for $\Sigma_b\to B\Delta$. For three-body modes we focus on octet baryon final states. The leading three-dominated modes are $\bar B^0\to p\bar n\pi^-(\rho^-), n\bar p\pi^+(\rho^+)$ with a branching ratio of order $3\times 10^{-6}$ for $\bar B^0\to p\bar n\pi^-$ and $8\times 10^{-6}$ for $\bar B^0\to p\bar n\rho^-$. The penguin-dominated decays with strangeness in the meson, e.g., $B^-\to p\bar p K^{-(*)}$ and $\bar B^0\to p\bar n K^{-(*)}, n\bar n \bar K^{0(*)}$, have appreciable rates and the $N\bar N$ mass spectrum peaks at low mass. The penguin-dominated modes containing a strange baryon, e.g., $\bar B^0\to \Sigma^0\bar p\pi^+, \Sigma^-\bar n\pi^+$, have branching ratios of order $(1\sim 4)\times 10^{-6}$. In contrast, the decay rate of $\bar B^0\to\Lambda\bar p\pi^+$ is smaller. We explain why some of charmless three-body final states in which baryon-antibaryon pair production is accompanied by a meson have a larger rate than their two-body counterparts: either the pole diagrams for the former have an anti-triplet bottom baryon intermediate state, which has a large coupling to the $B$ meson and the nucleon, or they are dominated by the factorizable external $W$-emission process.Comment: 46 pages and 3 figures, to appear in Phys. Rev. D. Major changes are: (i) Calculations of two-body baryonic B decays involving a Delta resonance are modified, and (ii) Penguin-dominated modes B-> Sigma+N(bar)+p are discusse

The masses and decay widths of heavy hybrid mesons

We first derive the mass sum rules for the heavy hybrid mesons to obtain the binding energy and decay constants in the leading order of HQET. The pionic couplings between the lightest $1^{-+}$ hybrid $(Q\bar q g)$ and the lowest three heavy meson doublets are calculated with the light cone QCD sum rules. With $SU_f (3)$ flavor symmetry we calculate the widths for all the possible two-body decay processes with a Goldstone boson in the final state. The total width of the $1^{-+}$ hybrid is estimated to be 300 MeV. We find the dominant decay mode of the $1^{-+}$ hybrid is $1^{-+}\to \pi + 1^+$ where the $1^+$ heavy meson belongs to the $(1^+,2^+)$ doublet. Its branching ratio is about 80% so this mode can be used for the experimental search of the lowest heavy hybrid meson.Comment: 20 pages + 12 PS figures, introduction revised, Fig 7 updated, to appear in Phys. Rev.

Heavy quarkonium: progress, puzzles, and opportunities

A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

Measurements of J/psi --> p \bar{p}

The process J/\psi --> p \bar{p} is studied using 57.7 X 10^6 J/\psi events collected with the BESII detector at the Beijing Electron Positron Collider. The branching ratio is determined to be Br(J/\psi --> p \bar{p})=(2.26 +- 0.01 +- 0.14) X 10^{-3}, and the angular distribution is well described by \frac{dN}{d cos\theta_p}=1+\alpha\cos^2\theta_p with \alpha = 0.676 +- 0.036 +- 0.042, where \theta_p is the angle between the proton and beam directions. The value of \alpha obtained is in good agreement with the predictions of first-order QCD.Comment: 6 pages, 2 figures, RevTex4, Submitted to Phys.Lett.

Study of the decay mechanism for B+ to p pbar K+ and B+ to p pbar pi+

We study the characteristics of the low mass ppbar enhancements near threshold in the three-body decays B+ to p pbar K+ and B+ to p pbar pi+. We observe that the proton polar angle distributions in the ppbar helicity frame in the two decays have the opposite polarity, and measure the forward-backward asymmetries as a function of the ppbar mass for the p pbar K+ mode. We also search for the intermediate two-body decays, B+ to pbar Delta++ and B+ to p Delta0bar, and set upper limits on their branching fractions. These results are obtained from a 414 fb^{-1} data sample that contains 449 times 10^6 BBbar events collected near the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+ e- collider.Comment: 15 pages, 5 figures (14 figure files), revisions to Phys. Lett.

Uncoupling of oxidative phosphorylation and antioxidants affect fusion of primary human myoblasts in vitro

Reactive oxygen species are at the origin of muscular fatigue and atrophy. They are also linked to muscular dystrophies, a group of human genetic diseases. Several studies point to the benefits of application of antioxidants and uncouplers of oxidative phosphorylation to improve the functional activity of normal and pathological muscles. Other studies point to potential dangers of these compounds. Aim. To study the effect of mitochondria-targeted antioxidants and uncouplers of oxidative phosphorylation on muscle differentiation. Methods. Muscle differentiation was induced by serum starvation and monitored by troponin T staining. Results. the mitochondria-targeted uncoupler of oxidative phosphorylation C12TPP, but not the mitochondria-targeted antioxidant SkQ1, inhibit fusion of primary myoblasts upon their differentiation, but do not affect the synthesis of troponin T, a protein marker of muscle differentiation. Conclusion. The effect of C12TPP could be at least partially mediated by inhibition of reactive oxygen species (ROS) production since antioxidant N-acetylcysteine at high doses also inhibited differentiation of myoblasts.Активні форми кисню (АФК) можуть викликати м'язову втому і атрофію м'язів. АФК також пов'язані з м'язовими дистрофії. Безліч досліджень вказує на позитивний вплив антиоксидантів і разобщітелей окисного фосфорилювання на функціональну активність м'язів в нормі та патології. Мета. Вивчити вплив мітохондріальної-спрямованих антиоксидантів і разобщітелей окисного фосфорилювання на диференціювання первинних міобластів людини. Методи. Результати. мітохондріальної-спрямований разобщитель окисного фосфорилювання C12TPP, але не мітохондріальної-спрямований антиоксидант SkQ1, пригнічує злиття міобластів при диференціюванні, при цьому не впливаючи на експресію тропонина Т, білкового маркера м'язової диференціювання. Висновки. Вплив C12TPP може бути частково викликано пригніченням АФК, так як високі концентрації класичного антиоксиданту N-ацетилцистеїну також інгібували диференціювання міобластів людини.Активные формы кислорода (АФК) могут вызывать мышечную усталость и атрофию мышц. АФК также связаны с мышечными дистрофиями. Множество исследований указывает на положительное влияние антиоксидантов и разобщителей окислительного фосфорилирования на функциональную активность мышц в норме и патологии. Цель. Изучить влияние митохондриально-направленных антиоксидантов и разобщителей окислительного фосфорилирования на дифференцировку первичных миобластов человека. Методы. Результаты. митохондриально-направленный разобщитель окислительного фосфорилирования C12TPP, но не митохондриально-направленный антиоксидант SkQ1, ингибирует слияние миобластов при дифференцировке, при этом не влияя на экспрессию тропонина Т, белкового маркера мышечной дифференцировки. Выводы. Влияние C12TPP может быть частично вызвано ингибированием АФК, так как высокие концентрации классического антиоксиданта N-ацетилцистеина также ингибировали дифференцировку миобластов человека