KamLAND Bounds on Solar Antineutrinos and neutrino transition magnetic moments

We investigate the possibility of detecting solar electron antineutrinos with the KamLAND experiment. These electron antineutrinos are predicted by spin-flavor oscillations at a significant rate even if this mechanism is not the leading solution to the SNP. KamLAND is sensitive to antineutrinos originated from solar ${}^8$B neutrinos. From KamLAND negative results after 145 days of data taking, we obtain model independent limits on the total flux of solar electron antineutrinos $\Phi({}^8 B)< 1.1-3.5\times 10^4 cm^{-2}\ s^{-1}$, more than one order of magnitude smaller than existing limits, and on their appearance probability$P<0.15%$(95antineutrino production by spin-flavor precession, this upper bound implies an upper limit on the product of the intrinsic neutrino magnetic moment and the value of the solar magnetic field$\mu B< 2.3\times 10^{-21}$MeV 95LMA$(\Delta m^2, \tan^2\theta)$values). Limits on neutrino transition moments are also obtained. For realistic values of other astrophysical solar parameters these upper limits would imply that the neutrino magnetic moment is constrained to be, in the most conservative case,$\mu\lsim 3.9\times 10^{-12} \mu_B$(95CL) for a relatively small field$B= 50$kG. For higher values of the magnetic field we obtain:$\mu\lsim 9.0\times 10^{-13} \mu_B$for field$B= 200$kG and$\mu\lsim 2.0\times 10^{-13} \mu_B$for field$B= 1000$ kG at the same statistical significance.Comment: 13 pages, 2 figure

Intramolecular C-H oxidative addition to iridium(I) triggered by trimethyl phosphite in N,N′-diphosphanesilanediamine complexes

The reaction of [Ir(SiNP)(cod)][PF] ([1][PF]) and of IrCl(SiNP)(cod) (5) (SiNP = SiMe{N(4-CHCH)PPh}) with trimethyl phosphite affords the iridium(iii) derivatives of the formula [IrHCl(SiNP-H){P(OMe)}] (x = 0, 3; x = 1, 6) containing the κC,P,P′-coordinated SiNP-H ligand (SiNP-H = Si(CH)(CH){N(4-CHCH)PPh}). The thermally unstable pentacoordinated cation [Ir(SiNP){P(OMe)}(cod)] (2) has been detected as an intermediate of the reaction and has been fully characterised in solution. Also, the mechanism of the C-H oxidative addition has been elucidated by DFT calculations showing that the square planar iridium(i) complexes of the formula [IrCl(SiNP){P(OMe)}] (x = 0, 4; x = 1, 7) should be firstly obtained from 2 and finally should undergo the C-H oxidative addition to iridium(i) via a concerted intramolecular mechanism. The influence of the counterion of 2 on the outcome of the C-H oxidative addition reaction has also been investigated.Financial support from Spanish “Ministerio de Economía y Competitividad” (CTQ2013–42532–P), “Diputación General de Aragón” (Group E07) and University of Zaragoza (UZCUD2014–CIE–13) is gratefully acknowledged.Peer Reviewe

Inhibition of TXNRD or SOD1 overcomes NRF2-mediated resistance to β-lapachone

Alterations in the NRF2/KEAP1 pathway result in the constitutive activation of NRF2, leading to the aberrant induction of antioxidant and detoxification enzymes, including NQO1. The NQO1 bioactivatable agent β-lapachone can target cells with high NQO1 expression but relies in the generation of reactive oxygen species (ROS), which are actively scavenged in cells with NRF2/KEAP1 mutations. However, whether NRF2/KEAP1 mutations influence the response to β-lapachone treatment remains unknown. To address this question, we assessed the cytotoxicity of β-lapachone in a panel of NSCLC cell lines bearing either wild-type or mutant KEAP1. We found that, despite overexpression of NQO1, KEAP1 mutant cells were resistant to β-lapachone due to enhanced detoxification of ROS, which prevented DNA damage and cell death. To evaluate whether specific inhibition of the NRF2-regulated antioxidant enzymes could abrogate resistance to β-lapachone, we systematically inhibited the four major antioxidant cellular systems using genetic and/or pharmacologic approaches. We demonstrated that inhibition of the thioredoxin-dependent system or copper-zinc superoxide dismutase (SOD1) could abrogate NRF2-mediated resistance to β-lapachone, while depletion of catalase or glutathione was ineffective. Interestingly, inhibition of SOD1 selectively sensitized KEAP1 mutant cells to β-lapachone exposure. Our results suggest that NRF2/KEAP1 mutational status might serve as a predictive biomarker for response to NQO1-bioactivatable quinones in patients. Further, our results suggest SOD1 inhibition may have potential utility in combination with other ROS inducers in patients with KEAP1/NRF2 mutations

Relic Neutralino Density in Scenarios with Intermediate Unification Scale

We analyse the relic neutralino density in supersymmetric models with an intermediate unification scale. In particular, we present concrete cosmological scenarios where the reheating temperature is as small as $\cal{O}$ $1 - 1000$ MeV). When this temperature is associated to the decay of moduli fields producing neutralinos, we show that the relic abundance increases considerably with respect to the standard thermal production. Thus the neutralino becomes a good dark matter candidate with 0.1\lsim \Omega h^2 \lsim 0.3, even for regions of the parameter space where large neutralino-nucleon cross sections, compatible with current dark matter experiments, are present. This is obtained for intermediate scales $M_I\sim 10^{11}-10^{14}$ GeV, and moduli masses $m_\phi\sim 100-1000$ GeV. On the other hand, when the above temperature is associated to the decay of an inflaton field, the relic abundance is too small.Comment: Latex, 11 pages, 2 figure

KamLAND, solar antineutrinos and the solar magnetic field

In this work the possibility of detecting solar electron antineutrinos produced by a solar core magnetic field from the KamLAND recent observations is investigated. We find a scaling of the antineutrino probability with respect to the magnetic field profile in the sense that the same probability function can be reproduced by any profile with a suitable peak field value. In this way the solar electron antineutrino spectrum can be unambiguosly predicted. We use this scaling and the negative results indicated by the KamLAND experiment to obtain upper bounds on the solar electron antineutrino flux. We get $\phi_{\bar\nu}<3.8\times 10^{-3}\phi(^8B)$ at 95% CL. For 90% CL this becomes $\phi_{\bar\nu}<3.4\times 10^{-3}\phi(^8B)$, an improvement by a factor of 3-5 with respect to existing bounds. These limits are independent of the detailed structure of the magnetic field in the solar interior. We also derive upper bounds on the peak field value which are uniquely determined for a fixed solar field profile. In the most efficient antineutrino producing case, we get (95% CL) an upper limit on the product of the neutrino magnetic moment by the solar field $\mu B< 2.8\times 10^{-19}$ MeV or $B_0 \leq 4.9 \times 10^7 G$ for $\mu_\nu=10^{-12}\mu_B$.Comment: 15 pages. References corrected. Minor changes in the tex

Neutrino Magnetic Moments and Minimal Supersymmetric SO(10) Model

We examine supersymmetric contributions to transition magnetic moments of Majorana neutrinos. We first give the general formula for it. In concrete evaluations, informations of neutrino mass matrix elements including CP phases are necessary. Using unambiguously determined neutrino mass matrices in recently proposed minimal supersymmetric SO(10) model, the transition magnetic moments are calculated. The resultant neutrino magnetic moments are found to be roughly an order of magnitude larger than those calculated in the standard model extended to incorporate the see-saw mechanism.Comment: 8 pages, 4 figures, the version to be published in International Journal of Modern Physics

Tandem isomerization/telomerization of long chain dienes.

The first example of a tandem reaction involving double-bond migration in combination with telomerization is reported. Homogeneous and heterogeneous Ru catalysts were employed as isomerization catalysts, and telomerization was realized using a homogeneous Pd(0) precursor complex with a N-heterocyclic carbene (IMes) ligand. Overall conversions approaching 60% were achieved with the best selectivity to telomerization products of 91% attained at 11% conversion. Conversion was markedly higher in the presence of longer-chain alcohol (1-butanol) as the nucleophile (telogen).Financial support from Engineering and Physical Sciences Research Council (EPSRC, UK) via grant GR/S86112/01 is gratefully acknowledged.This is the final published version, which can also be found on the publisher's website at: http://journal.frontiersin.org/Journal/10.3389/fchem.2014.00037/ful

Formation of dispersive hybrid bands at an organic-metal interface

An electronic band with quasi-one dimensional dispersion is found at the interface between a monolayer of a charge-transfer complex (TTF-TCNQ) and a Au(111) surface. Combined local spectroscopy and numerical calculations show that the band results from a complex mixing of metal and molecular states. The molecular layer folds the underlying metal states and mixes with them selectively, through the TTF component, giving rise to anisotropic hybrid bands. Our results suggest that, by tuning the components of such molecular layers, the dimensionality and dispersion of organic-metal interface states can be engineered

Tetranuclear [Rh4(μ-PyS2) 2(diolefin)4] complexes as building blocks for new inorganic architectures: Synthesis of coordination polymers and heteropolynuclear complexes with electrophilic d8 and d10 metal fragments

The reaction of [Rh4(μ-PyS2)2(cod) 4] (PYS2 = 2,6-pyridinedithiolate, cod = 1,5-cyclooctadiene) with CF3SO3Me gave the cationic complex [Rh4(μ-PyS2Me)2(cod) 4][CF3SO3]2 (1) with two 6-(thiomethyl)pyridine-2-thiolate bridging ligands from the attack of Me+ at the terminal sulfur atoms of the starting material. Under identical conditions [Rh4(μ-PyS2)2(tfbb)4] (tfbb = tetrafluorobenzobarrelene) reacted with CF3SO3Me to give the mixed-ligand complex [Rh4(μ-PyS2)(μ-PyS 2Me)(tfbb)4][CF3SO3] (2). The nucleophilicity of the bridging ligands in the complexes [Rh4(μ -PyS2)2(diolefin)4] was exploited to prepare heteropolynuclear species. Reactions with [Au(PPh3)(Me 2CO)][ClO4] gave the hexanuclear complexes [(PPh 3)2Au2Rh4(μ-PyS2) 2(diolefin)4][ClO4]2 (diolefin = cod (3), tfbb (4)). The structure of 4, solved by X-ray diffraction methods, showed the coordination of the [Au(PPh3)]+ fragments to the peripheral sulfur atoms in [Rh4(μ-PyS2) 2(diolefin)4 along with their interaction with the neighbor rhodium atoms. Neutral coordination polymers of formula [CIMRh 4(μ-PyS2)2(diolefin)4] n (M = Cu (5, 6), Au (7)) result from the self-assembly of alternating [Rh4(μ-PyS2)2(diolefin) 4] ([Rh4]) blocks and MCI linkers. The formation of the infinite polymetallic chains was found to be chiroselective for M = Cu; one particular chain contains exclusively homochiral [Rh4] complexes. Cationic heterometallic coordination polymers of formula [MRh 4(μ-PyS2)2(diolefin)4] n (M = Ag (8, 9), Cu (10, 11)) and [Rh5(μ-PyS 2)2(diolefin)5]n[BF 4]n (12, 13) result from the reactions of [Rh 4] with [Cu(CH3CN)4]BF4, AgBF 4, and [Rh(diolefin)(Me2CO)2]BF4, respectively. The heterometallic coordination polymers exhibit a weak electric conductivity in the solid state in the range (1.2-2.8) × 10-7 S cm-1.The financial support from Ministerio de Ciencia y Tecnología (MCyT(DGI)/FEDER, Projects BQU2002-00074 and BQU2000-1170) is gratefully acknowledged.Peer Reviewe

Early (Ti, Zr)-late (Rh, Ir) heteronuclear complexes with bridging sulphido ligands

[EN]: We report in this account on the controlled synthesis of novel d0-d8 early-late heteropolynuclear diolefin and carbonyl clusters. The synthetic approach was based on additive-deprotonation reactions involving the titanium and zirconium bis-hydrosulphido complexes of formula [Cp2Ti(SH)2] and [Cptt 2Zr(SH)2] and appropriate rhodium and iridium diolefin and carbonyl compounds. The significant differences between the resulting early-late complexes and their structures coming from the titanium or zirconium metalloligand precursors are highlighted. The catalytic activity of some representative titanium-rhodium and zirconium-rhodium compounds towards alkene hydroformylation was explored. Interestingly, the heterotetranuclear 'CpTi(μ3-S)3Rh3' structure was maintained as such under mild conditions.[FR]: Nous rapportons dans cet article la préparation contrôlée de nouveaux clusters hétéropolynucléaires early-late d0–d8 portant les ligands oléfine et carbonyle. La réaction de déprotonation–addition a été la méthode de synthèse utilisée et implique la condensation de complexes bis-hydrogénosulfure du titane et du zirconium, de formule [Cp2Ti(SH)2] et [Cptt2Zr(SH)2], sur les composés adéquats du rhodium et de l’iridium portant les ligands oléfine et carbonyle. Les différences significatives de structure entre les complexes early-late ainsi préparés, dues à la nature du métalloligand précurseur du titane ou du zirconium employé, sont mises en évidence. L’activité catalytique de quelques composés représentatifs titane–rhodium et zirconium–rhodium dans l’hydroformylation d’alcènes a été mesurée. Il convient de noter que la structure hétérotétranucléaire « CpTi(μ3-S)3Rh3 » est maintenue comme telle sous des conditions douces de réaction.Peer Reviewe