2,390 research outputs found
Dual enzyme-triggered controlled release on capped nanometric silica mesoporous supports
We thank the Spanish Government (project MAT2009-14564-C04 and CTQ2007-64735-AR07) the Generalitat Valencia (project PROMETEO/2009/016) for support. A.A. and L.M. thank the Generalitat Valenciana for their Santiago Grisolia Fellowship and VALI+D postdoctoral contract, respectively. We thank the confocal microscopy service from CIPF for technical support.Agostini, A.; MondragĂłn MartĂnez, L.; Coll Merino, MC.; Aznar Gimeno, E.; Marcos MartĂnez, MD.; MartĂnez Mañez, R.; SancenĂłn Galarza, F.... (2012). Dual enzyme-triggered controlled release on capped nanometric silica mesoporous supports. ChemistryOpen. 1:17-20. https://doi.org/10.1002/open.201200003S17201Saha, S., Leung, K. C.-F., Nguyen, T. D., Stoddart, J. F., & Zink, J. I. (2007). Nanovalves. Advanced Functional Materials, 17(5), 685-693. doi:10.1002/adfm.200600989Trewyn, B. G., Slowing, I. I., Giri, S., Chen, H.-T., & Lin, V. S.-Y. (2007). Synthesis and Functionalization of a Mesoporous Silica Nanoparticle Based on the SolâGel Process and Applications in Controlled Release. Accounts of Chemical Research, 40(9), 846-853. doi:10.1021/ar600032uAznar, E., MartĂnez-Måñez, R., & SancenĂłn, F. (2009). Controlled release using mesoporous materials containing gate-like scaffoldings. Expert Opinion on Drug Delivery, 6(6), 643-655. doi:10.1517/17425240902895980Beck, J. S., Vartuli, J. C., Roth, W. J., Leonowicz, M. E., Kresge, C. T., Schmitt, K. D., ⊠Schlenker, J. L. (1992). A new family of mesoporous molecular sieves prepared with liquid crystal templates. Journal of the American Chemical Society, 114(27), 10834-10843. doi:10.1021/ja00053a020Wight, A. P., & Davis, M. E. (2002). Design and Preparation of OrganicâInorganic Hybrid Catalysts. Chemical Reviews, 102(10), 3589-3614. doi:10.1021/cr010334mKickelbick, G. (2004). Mesoporöse anorganisch-organische Hybridmaterialien. Angewandte Chemie, 116(24), 3164-3166. doi:10.1002/ange.200301751Kickelbick, G. (2004). Hybrid InorganicâOrganic Mesoporous Materials. Angewandte Chemie International Edition, 43(24), 3102-3104. doi:10.1002/anie.200301751Mal, N. K., Fujiwara, M., & Tanaka, Y. (2003). Photocontrolled reversible release of guest molecules from coumarin-modified mesoporous silica. Nature, 421(6921), 350-353. doi:10.1038/nature01362Mal, N. K., Fujiwara, M., Tanaka, Y., Taguchi, T., & Matsukata, M. (2003). Photo-Switched Storage and Release of Guest Molecules in the Pore Void of Coumarin-Modified MCM-41. Chemistry of Materials, 15(17), 3385-3394. doi:10.1021/cm0343296Zhu, Y., & Fujiwara, M. (2007). Installing Dynamic Molecular Photomechanics in Mesopores: A Multifunctional Controlled-Release Nanosystem. Angewandte Chemie, 119(13), 2291-2294. doi:10.1002/ange.200604850Zhu, Y., & Fujiwara, M. (2007). Installing Dynamic Molecular Photomechanics in Mesopores: A Multifunctional Controlled-Release Nanosystem. Angewandte Chemie International Edition, 46(13), 2241-2244. doi:10.1002/anie.200604850Liu, N., Chen, Z., Dunphy, D. R., Jiang, Y.-B., Assink, R. A., & Brinker, C. J. (2003). Angewandte Chemie, 115(15), 1773-1776. doi:10.1002/ange.200250189Liu, N., Chen, Z., Dunphy, D. R., Jiang, Y.-B., Assink, R. A., & Brinker, C. J. (2003). Photoresponsive Nanocomposite Formed by Self-Assembly of an Azobenzene-Modified Silane. Angewandte Chemie International Edition, 42(15), 1731-1734. doi:10.1002/anie.200250189Aznar, E., CasasĂșs, R., GarcĂa-Acosta, B., Marcos, M. D., MartĂnez-Måñez, R., SancenĂłn, F., ⊠AmorĂłs, P. (2007). Photochemical and Chemical Two-Channel Control of Functional Nanogated Hybrid Architectures. Advanced Materials, 19(17), 2228-2231. doi:10.1002/adma.200601958Park, C., Lee, K., & Kim, C. (2009). Photoresponsive Cyclodextrin-Covered Nanocontainers and Their Sol-Gel Transition Induced by Molecular Recognition. Angewandte Chemie International Edition, 48(7), 1275-1278. doi:10.1002/anie.200803880Ferris, D. P., Zhao, Y.-L., Khashab, N. M., Khatib, H. A., Stoddart, J. F., & Zink, J. I. (2009). Light-Operated Mechanized Nanoparticles. Journal of the American Chemical Society, 131(5), 1686-1688. doi:10.1021/ja807798gLin, Q., Huang, Q., Li, C., Bao, C., Liu, Z., Li, F., & Zhu, L. (2010). Anticancer Drug Release from a Mesoporous Silica Based Nanophotocage Regulated by Either a One- or Two-Photon Process. Journal of the American Chemical Society, 132(31), 10645-10647. doi:10.1021/ja103415tKneĆŸeviÄ, N. Ćœ., Trewyn, B. G., & Lin, V. S.-Y. (2011). Light- and pH-Responsive Release of Doxorubicin from a Mesoporous Silica-Based Nanocarrier. Chemistry - A European Journal, 17(12), 3338-3342. doi:10.1002/chem.201002960KneĆŸeviÄ, N. Ćœ., Trewyn, B. G., & Lin, V. S.-Y. (2011). Functionalized mesoporous silica nanoparticle-based visible light responsive controlled release delivery system. Chemical Communications, 47(10), 2817. doi:10.1039/c0cc04424eTrewyn, B. G., Giri, S., Slowing, I. I., & Lin, V. S.-Y. (2007). Mesoporous silica nanoparticle based controlled release, drug delivery, and biosensor systems. Chemical Communications, (31), 3236. doi:10.1039/b701744hTorney, F., Trewyn, B. G., Lin, V. S.-Y., & Wang, K. (2007). Mesoporous silica nanoparticles deliver DNA and chemicals into plants. Nature Nanotechnology, 2(5), 295-300. doi:10.1038/nnano.2007.108Radu, D. R., Lai, C.-Y., Jeftinija, K., Rowe, E. W., Jeftinija, S., & Lin, V. S.-Y. (2004). A Polyamidoamine Dendrimer-Capped Mesoporous Silica Nanosphere-Based Gene Transfection Reagent. Journal of the American Chemical Society, 126(41), 13216-13217. doi:10.1021/ja046275mGiri, S., Trewyn, B. G., Stellmaker, M. P., & Lin, V. S.-Y. (2005). Stimuli-Responsive Controlled-Release Delivery System Based on Mesoporous Silica Nanorods Capped with Magnetic Nanoparticles. Angewandte Chemie, 117(32), 5166-5172. doi:10.1002/ange.200501819Giri, S., Trewyn, B. G., Stellmaker, M. P., & Lin, V. S.-Y. (2005). Stimuli-Responsive Controlled-Release Delivery System Based on Mesoporous Silica Nanorods Capped with Magnetic Nanoparticles. Angewandte Chemie International Edition, 44(32), 5038-5044. doi:10.1002/anie.200501819Fujiwara, M., Terashima, S., Endo, Y., Shiokawa, K., & Ohue, H. (2006). Switching catalytic reaction conducted in pore void of mesoporous material by redox gate control. Chemical Communications, (44), 4635. doi:10.1039/b610444dLiu, R., Zhao, X., Wu, T., & Feng, P. (2008). Tunable Redox-Responsive Hybrid Nanogated Ensembles. Journal of the American Chemical Society, 130(44), 14418-14419. doi:10.1021/ja8060886Nguyen, T. D., Liu, Y., Saha, S., Leung, K. C.-F., Stoddart, J. F., & Zink, J. I. (2007). Design and Optimization of Molecular Nanovalves Based on Redox-Switchable Bistable Rotaxanes. Journal of the American Chemical Society, 129(3), 626-634. doi:10.1021/ja065485rCasasĂșs, R., Marcos, M. D., MartĂnez-Måñez, R., Ros-Lis, J. V., Soto, J., Villaescusa, L. A., ⊠Latorre, J. (2004). Toward the Development of Ionically Controlled Nanoscopic Molecular Gates. Journal of the American Chemical Society, 126(28), 8612-8613. doi:10.1021/ja048095iCasasĂșs, R., Climent, E., Marcos, M. D., MartĂnez-Måñez, R., SancenĂłn, F., Soto, J., ⊠Ruiz, E. (2008). Dual Aperture Control on pH- and Anion-Driven Supramolecular Nanoscopic Hybrid Gate-like Ensembles. Journal of the American Chemical Society, 130(6), 1903-1917. doi:10.1021/ja0756772Aznar, E., Marcos, M. D., MartiÌnez-MaÌnÌez, R., SancenoÌn, F., Soto, J., AmoroÌs, P., & Guillem, C. (2009). pH- and Photo-Switched Release of Guest Molecules from Mesoporous Silica Supports. Journal of the American Chemical Society, 131(19), 6833-6843. doi:10.1021/ja810011pAngelos, S., Yang, Y.-W., Khashab, N. M., Stoddart, J. F., & Zink, J. I. (2009). Dual-Controlled Nanoparticles Exhibiting AND Logic. Journal of the American Chemical Society, 131(32), 11344-11346. doi:10.1021/ja9042752Angelos, S., Yang, Y.-W., Patel, K., Stoddart, J. F., & Zink, J. I. (2008). pH-Responsive Supramolecular Nanovalves Based on Cucurbit[6]uril Pseudorotaxanes. Angewandte Chemie, 120(12), 2254-2258. doi:10.1002/ange.200705211Angelos, S., Yang, Y.-W., Patel, K., Stoddart, J. F., & Zink, J. I. (2008). pH-Responsive Supramolecular Nanovalves Based on Cucurbit[6]uril Pseudorotaxanes. Angewandte Chemie International Edition, 47(12), 2222-2226. doi:10.1002/anie.200705211Angelos, S., Khashab, N. M., Yang, Y.-W., Trabolsi, A., Khatib, H. A., Stoddart, J. F., & Zink, J. I. (2009). pH Clock-Operated Mechanized Nanoparticles. Journal of the American Chemical Society, 131(36), 12912-12914. doi:10.1021/ja9010157Du, L., Liao, S., Khatib, H. A., Stoddart, J. F., & Zink, J. I. (2009). Controlled-Access Hollow Mechanized Silica Nanocontainers. Journal of the American Chemical Society, 131(42), 15136-15142. doi:10.1021/ja904982jYang, Q., Wang, S., Fan, P., Wang, L., Di, Y., Lin, K., & Xiao, F.-S. (2005). pH-Responsive Carrier System Based on Carboxylic Acid Modified Mesoporous Silica and Polyelectrolyte for Drug Delivery. Chemistry of Materials, 17(24), 5999-6003. doi:10.1021/cm051198vPark, C., Oh, K., Lee, S. C., & Kim, C. (2007). Controlled Release of Guest Molecules from Mesoporous Silica Particles Based on a pH-Responsive Polypseudorotaxane Motif. Angewandte Chemie, 119(9), 1477-1479. doi:10.1002/ange.200603404Park, C., Oh, K., Lee, S. C., & Kim, C. (2007). Controlled Release of Guest Molecules from Mesoporous Silica Particles Based on a pH-Responsive Polypseudorotaxane Motif. Angewandte Chemie International Edition, 46(9), 1455-1457. doi:10.1002/anie.200603404Chen, L., Di, J., Cao, C., Zhao, Y., Ma, Y., Luo, J., ⊠Jiang, L. (2011). A pH-driven DNA nanoswitch for responsive controlled release. Chemical Communications, 47(10), 2850. doi:10.1039/c0cc04765aCliment, E., Bernardos, A., MartiÌnez-MaÌnÌez, R., Maquieira, A., Marcos, M. D., Pastor-Navarro, N., ⊠AmoroÌs, P. (2009). Controlled Delivery Systems Using Antibody-Capped Mesoporous Nanocontainers. Journal of the American Chemical Society, 131(39), 14075-14080. doi:10.1021/ja904456dCliment, E., MartĂnez-Måñez, R., SancenĂłn, F., Marcos, M. D., Soto, J., Maquieira, A., & AmorĂłs, P. (2010). Controlled Delivery Using Oligonucleotide-Capped Mesoporous Silica Nanoparticles. Angewandte Chemie, 122(40), 7439-7441. doi:10.1002/ange.201001847Climent, E., MartĂnez-Måñez, R., SancenĂłn, F., Marcos, M. D., Soto, J., Maquieira, A., & AmorĂłs, P. (2010). Controlled Delivery Using Oligonucleotide-Capped Mesoporous Silica Nanoparticles. Angewandte Chemie International Edition, 49(40), 7281-7283. doi:10.1002/anie.201001847Patel, K., Angelos, S., Dichtel, W. R., Coskun, A., Yang, Y.-W., Zink, J. I., & Stoddart, J. F. (2008). Enzyme-Responsive Snap-Top Covered Silica Nanocontainers. Journal of the American Chemical Society, 130(8), 2382-2383. doi:10.1021/ja0772086Schlossbauer, A., Kecht, J., & Bein, T. (2009). Biotin-Avidin as a Protease-Responsive Cap System for Controlled Guest Release from Colloidal Mesoporous Silica. Angewandte Chemie, 121(17), 3138-3141. doi:10.1002/ange.200805818Schlossbauer, A., Kecht, J., & Bein, T. (2009). Biotin-Avidin as a Protease-Responsive Cap System for Controlled Guest Release from Colloidal Mesoporous Silica. Angewandte Chemie International Edition, 48(17), 3092-3095. doi:10.1002/anie.200805818Bernardos, A., Aznar, E., Marcos, M. D., MartĂnez-Måñez, R., SancenĂłn, F., Soto, J., ⊠AmorĂłs, P. (2009). Enzyme-Responsive Controlled Release Using Mesoporous Silica Supports Capped with Lactose. Angewandte Chemie, 121(32), 5998-6001. doi:10.1002/ange.200900880Bernardos, A., Aznar, E., Marcos, M. D., MartĂnez-Måñez, R., SancenĂłn, F., Soto, J., ⊠AmorĂłs, P. (2009). Enzyme-Responsive Controlled Release Using Mesoporous Silica Supports Capped with Lactose. Angewandte Chemie International Edition, 48(32), 5884-5887. doi:10.1002/anie.200900880Bernardos, A., MondragĂłn, L., Aznar, E., Marcos, M. D., MartĂnez-Måñez, R., SancenĂłn, F., ⊠AmorĂłs, P. (2010). Enzyme-Responsive Intracellular Controlled Release Using Nanometric Silica Mesoporous Supports Capped with «Saccharides». ACS Nano, 4(11), 6353-6368. doi:10.1021/nn101499dPark, C., Kim, H., Kim, S., & Kim, C. (2009). Enzyme Responsive Nanocontainers with Cyclodextrin Gatekeepers and Synergistic Effects in Release of Guests. Journal of the American Chemical Society, 131(46), 16614-16615. doi:10.1021/ja9061085Thornton, P. D., & Heise, A. (2010). Highly Specific Dual Enzyme-Mediated Payload Release from Peptide-Coated Silica Particles. Journal of the American Chemical Society, 132(6), 2024-2028. doi:10.1021/ja9094439Coll, C., MondragĂłn, L., MartĂnez-Måñez, R., SancenĂłn, F., Marcos, M. D., Soto, J., ⊠PĂ©rez-PayĂĄ, E. (2011). Enzyme-Mediated Controlled Release Systems by Anchoring Peptide Sequences on Mesoporous Silica Supports. Angewandte Chemie, 123(9), 2186-2188. doi:10.1002/ange.201004133Coll, C., MondragĂłn, L., MartĂnez-Måñez, R., SancenĂłn, F., Marcos, M. D., Soto, J., ⊠PĂ©rez-PayĂĄ, E. (2011). Enzyme-Mediated Controlled Release Systems by Anchoring Peptide Sequences on Mesoporous Silica Supports. Angewandte Chemie International Edition, 50(9), 2138-2140. doi:10.1002/anie.201004133Cabrera, S., El Haskouri, J., Guillem, C., Latorre, J., BeltrĂĄn-Porter, A., BeltrĂĄn-Porter, D., ⊠AmorĂłs *, P. (2000). Generalised syntheses of ordered mesoporous oxides: the atrane route. Solid State Sciences, 2(4), 405-420. doi:10.1016/s1293-2558(00)00152-7Goldcamp, M. J., Rosa, D. T., Landers, N. A., Mandel, S. M., Krause Bauer, J. A., & Baldwin, M. J. (2000). Facile and Versatile Synthesis of Polydentate Metal Chelators with Both Amide and Oxime Donor Groups. Synthesis, 2000(14), 2033-2038. doi:10.1055/s-2000-8724Felix, F., Ferguson, J., Guedel, H. U., & Ludi, A. (1980). The electronic spectrum of tris(2,2â-bipyridine)ruthenium(2+). Journal of the American Chemical Society, 102(12), 4096-4102. doi:10.1021/ja00532a019Lytle, F. E., & Hercules, D. M. (1969). Luminescence of tris(2,2â-bipyridine)ruthenium(II) dichloride. Journal of the American Chemical Society, 91(2), 253-257. doi:10.1021/ja01030a00
Measurement of time-dependent CP violation parameters in B0 â KS0 KS0 KS0 decays at Belle
We measure the time-dependent CP violation parameters in B0âKS0KS0KS0 decays using 772Ă106BBÂŻ pairs collected at the Ï(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. The obtained mixing-induced and direct CP asymmetries are -0.71±0.23 (stat)±0.05 (syst) and 0.12±0.16 (stat)±0.05 (syst), respectively. These values are consistent with the Standard Model predictions. The significance of CP violation differs from zero by 2.5 standard deviations. © 2021 authors. Published by the American Physical Society
Safety and Efficacy of Dacomitinib in Korean Patients with KRAS Wild-Type Advanced NonâSmall-Cell Lung Cancer Refractory to Chemotherapy and Erlotinib or Gefitinib: A Phase I/II Trial
IntroductionDacomitinib (PF-00299804), an irreversible pan-human epidermal growth factor receptor ([HER]-1/EGFR, HER-2, and HER-4) tyrosine kinase inhibitor, demonstrated antitumor activity in Western patients with nonâsmall-cell lung cancer (NSCLC) at a dose of 45 mg once daily. We report data from a phase I/II, multicenter, open-label study of Korean patients with refractory KRAS wild-type adenocarcinoma NSCLC (defined as patients with evidence of disease progression during or within 6 months of treatment with chemotherapy and gefitinib or erlotinib).MethodsThe phase I dose-finding portion identified the recommended phase II dose (RP2D) in Korean patients, evaluated safety, and characterized the pharmacokinetics of dacomitinib. In the phase II portion, patients received dacomitinib at the RP2D. The primary end point was progression-free survival at 4 months (PFS4m).ResultsTwelve patients enrolled in phase I, and 43 patients enrolled in phase II at the RP2D of 45 mg once daily. In phase II, PFS4m was 47.2% (95% confidence interval [CI], 31.6â61.3; one-sided p-value = 0.0007). Median PFS was 15.4 weeks (95% CI, 9.7â17.6); median overall survival was 46.3 weeks (95% CI, 32.7ânot reached); and the objective response rate was 17.1% (95% CI, 7.2â32.1). Common treatment-related adverse events were dermatitis acneiform, diarrhea, and paronychia; there were no treatment-related grade 4 or 5 adverse events. Pharmacokinetic parameters of dacomitinib in Korean patients were similar to those reported in Western patients. By patient report, NSCLC symptoms âcoughâ and âpainâ showed improvement within 3 weeks of initiating treatment.ConclusionsDacomitinib was well tolerated and had antitumor activity in Korean patients with NSCLC who had previously progressed on chemotherapy and an epidermal growth factor receptor tyrosine kinase inhibitor
On Aharonov-Casher bound states
In this work bound states for the Aharonov-Casher problem are considered.
According to Hagen's work on the exact equivalence between spin-1/2
Aharonov-Bohm and Aharonov-Casher effects, is known that the
term cannot be neglected in the
Hamiltonian if the spin of particle is considered. This term leads to the
existence of a singular potential at the origin. By modeling the problem by
boundary conditions at the origin which arises by the self-adjoint extension of
the Hamiltonian, we derive for the first time an expression for the bound state
energy of the Aharonov-Casher problem. As an application, we consider the
Aharonov-Casher plus a two-dimensional harmonic oscillator. We derive the
expression for the harmonic oscillator energies and compare it with the
expression obtained in the case without singularity. At the end, an approach
for determination of the self-adjoint extension parameter is given. In our
approach, the parameter is obtained essentially in terms of physics of the
problem.Comment: 11 pages, matches published versio
Molecular recognition of poly(A) by small ligands: an alternative method of analysis reveals nanomolar, cooperative and shape-selective binding
A few drug-like molecules have recently been found to bind poly(A) and induce a stable secondary structure (Tm â 60°C), even though this RNA homopolymer is single-stranded in the absence of a ligand. Here, we report results from experiments specifically designed to explore the association of small molecules with poly(A). We demonstrate that coralyne, the first small molecule discovered to bind poly(dA), binds with unexpectedly high affinity (Ka >107 Mâ1), and that the crescent shape of coralyne appears necessary for poly(A) binding. We also show that the binding of similar ligands to poly(A) can be highly cooperative. For one particular ligand, at least six ligand molecules are required to stabilize the poly(A) self-structure at room temperature. This highly cooperative binding produces very sharp transitions between unstructured and structured poly(A) as a function of ligand concentration. Given the fact that junctions between WatsonâCrick and A·A duplexes are tolerated, we propose that poly(A) sequence elements and appropriate ligands could be used to reversibly drive transitions in DNA and RNA-based molecular structures by simply diluting/concentrating a sample about the poly(A)-ligand âcritical concentrationâ. The ligands described here may also find biological or medicinal applications, owing to the 3âČ-polyadenylation of mRNA in living cells
Corrigendum: Therapeutic Effect of Intestinal Autochthonous Lactobacillus reuteri P16 Against Waterborne Lead Toxicity in Cyprinus carpio
Harmful effects of heavy metals are myriad. Lead (Pb) from soil and atmosphere contaminates water bodies and affects the aquatic animals. Our previous study confirmed the in vitro probiotic potential of Lactobacillus reuteri against Pb toxicity, but further investigation is necessary for gaining insights into the related protection mode. Therefore, in this study, we investigated the protective effects of the potential probiotic L. reuteri P16 against waterborne Pb exposure-induced toxicity in the freshwater fish Cyprinus carpio. Fish (average weight: 23.16â±â0.73âg) were allocated to four groups (control, Pb only, Pbâ+âL. reuteri P16, and L. reuteri P16 only) and Pb groups were exposed to waterborne Pb (1âmg Lâ1) for 6âweeks. L. reuteri P16 (108âCFU gâ1) supplemented diet was provided twice daily. Growth performances, hemato-biochemical parameters, innate immune responses, intestinal microbiota, and Pb accumulation in tissues were measured at the end of the trial. When the fish were exposed to Pb, dietary supplementation of L. reuteri P16 effectively decreased mortality and accumulation of Pb in tissues, and improved the growth performance. Co-treatment with Pb and L. reuteri P16 alleviated Pb exposure-induced oxidative stress, reversed alterations in hemato-biochemical parameters, improved innate immune parameters, and restored intestinal enzymatic activities. Moreover, L. reuteri P16 supplementation reversed the changes in intestinal microbiota in Pb-exposed fish. Furthermore, Pb exposure decreased the expressions of pro-inflammatory cytokines (TNF-α, IL-1ÎČ). However, the expression of heat shock proteins (HSP70 and HSP90) increased, which might have increased the cellular stress. Interestingly, the Pb-induced alterations of gene expressions were reversed by L. reuteri P16 supplementation. Thus, dietary administration of the potential probiotic L. reuteri P16 had several beneficial effects on growth performance and immune responses, decreased Pb accumulation in tissues, and reversed alterations in hematological responses of C. carpio. Furthermore, it offered direct protection against Pb-induced oxidative stress. Therefore, L. reuteri P16 may be a novel dietary supplement for enhancing growth performance and preventing Pb-exposure-induced toxicity in fish in aquaculture and aquatic products
B --> Phi K_S and Supersymmetry
The rare decay B --> Phi K_S is a well-known probe of physics beyond the
Standard Model because it arises only through loop effects yet has the same
time-dependent CP asymmetry as B --> Psi K_S. Motivated by recent data
suggesting new physics in B --> Phi K_S, we look to supersymmetry for possible
explanations, including contributions mediated by gluino loops and by Higgs
bosons. Chirality-preserving LL and RR gluino contributions are generically
small, unless gluinos and squarks masses are close to the current lower bounds.
Higgs contributions are also too small to explain a large asymmetry if we
impose the current upper limit on B(B_s --> mu mu). On the other hand,
chirality-flipping LR and RL gluino contributions can provide sizable effects
and while remaining consistent with related results in B --> Psi K_S, Delta
M_s, B --> X_s gamma and other processes. We discuss how the LR and RL
insertions can be distinguished using other observables, and we provide a
string-based model and other estimates to show that the needed sizes of mass
insertions are reasonable.Comment: 33 pages, 32 figures, Updated version for PRD. Includes discussions
of other recent works on this topic. Added discussions & plots for gluino
mass dependence and effects of theoretical uncertaintie
Scope and Mechanistic Study of the Coupling Reaction of α,ÎČ-Unsaturated Carbonyl Compounds with Alkenes: Uncovering Electronic Effects on Alkene Insertion vs Oxidative Coupling Pathways
The cationic ruthenium-hydride complex [(C6H6)(PCy3)(CO)RuH]+BF4â (1) was found to be a highly effective catalyst for the intermolecular conjugate addition of simple alkenes to α,ÎČ-unsaturated carbonyl compounds to give (Z)-selective tetrasubstituted olefin products. The analogous coupling reaction of cinnamides with electron-deficient olefins led to the oxidative coupling of two olefinic CâH bonds in forming (E)-selective diene products. The intramolecular version of the coupling reaction efficiently produced indene and bicyclic fulvene derivatives. The empirical rate law for the coupling reaction of ethyl cinnamate with propene was determined as follows: rate = k[1]1[propene]0[cinnamate]â1. A negligible deuterium kinetic isotope effect (kH/kD = 1.1 ± 0.1) was measured from both (E)-C6H5CHâC(CH3)CONHCH3 and (E)-C6H5CDâC(CH3)CONHCH3 with styrene. In contrast, a significant normal isotope effect (kH/kD = 1.7 ± 0.1) was observed from the reaction of (E)-C6H5CHâC(CH3)CONHCH3 with styrene and styrene-d8. A pronounced carbon isotope effect was measured from the coupling reaction of (E)-C6H5CHâCHCO2Et with propene (13C(recovered)/13C(virgin) at CÎČ = 1.019(6)), while a negligible carbon isotope effect (13C(recovered)/13C(virgin) at CÎČ = 0.999(4)) was obtained from the reaction of (E)-C6H5CHâC(CH3)CONHCH3 with styrene. Hammett plots from the correlation of para-substituted p-X-C6H4CHâCHCO2Et (X = OCH3, CH3, H, F, Cl, CO2Me, CF3) with propene and from the treatment of (E)-C6H5CHâCHCO2Et with a series of para-substituted styrenes p-Y-C6H4CHâCH2 (Y = OCH3, CH3, H, F, Cl, CF3) gave the positive slopes for both cases (Ï = +1.1 ± 0.1 and +1.5 ± 0.1, respectively). Eyring analysis of the coupling reaction led to the thermodynamic parameters, ÎH⧧ = 20 ± 2 kcal molâ1 and ÎS⧧ = â42 ± 5 eu. Two separate mechanistic pathways for the coupling reaction have been proposed on the basis of these kinetic and spectroscopic studies
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