A convenient route to optically pure α-alkyl-β-(sec-amino)alanines

The cyclization of N-Boc-α-alkylserines to corresponding β-lactones under Mitsunobu reaction conditions and the ring opening with heterocyclic amines (pyrrolidine, piperidine, morpholine and thiomorpholine) produced N-Boc-α-alkyl-β-(sec-amino)alanines. The removal of the Boc group gives di-hydrochlorides of non-protein amino acids

Mechanistic Study of a Ru-Xantphos Catalyst for Tandem Alcohol Dehydrogenation and Reductive Aryl-Ether Cleavage

We employ density functional theory (DFT) calculations and kinetics measurements to understand the mechanism of a xantphos-containing molecular ruthenium catalyst acting on an alkyl aryl ether linkage similar to that found in lignin to produce acetophenone and phenol. The most favorable reaction pathway suggested from DFT is compared to kinetics measurements, and good agreement is found between the predicted and the measured activation barriers. The DFT calculations reveal several interesting features, including an unusual 5-membered transition state structure for oxidative insertion in contrast to the typically proposed 3-membered transition state, a preference for an O-bound over a C-bound Ru-enolate, and a significant kinetic preference for the order of product release from the catalyst. The experimental measurements confirm that the reaction proceeds via a free ketone intermediate, but also suggest that the conversion of the intermediate ketone to acetophenone and phenol does not necessarily require ketone dissociation from the catalyst. Overall, this work elucidates the kinetically and thermodynamically preferred reaction pathways for tandem alcohol dehydrogenation and reductive ether bond cleavage by the ruthenium-xantphos catalyst. © 2013 American Chemical Society

N-Type Conjugated Polymer-Enabled Selective Dispersion of Semiconducting Carbon Nanotubes for Flexible CMOS-Like Circuits

Sorting of semiconducting single-walled carbon nanotubes (SWNTs) by conjugated polymers has attracted considerable attention recently because of its simplicity, high selectivity, and high yield. However, up to now, all the conjugated polymers used for SWNT sorting are electron-donating (p-type). Here, a high-mobility electron-accepting (n-type) polymer poly([N,N-bis(2-octyldodecyl)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,5-(2,2-bithiophene)) (P(NDI2OD-T2)) is utilized for the sorting of high-purity semiconducting SWNTs, as characterized by Raman spectroscopy, dielectric force spectroscopy and transistor measurements. In addition, the SWNTs sorted by P(NDI2OD-T2) have larger diameters than poly(3-dodecylthiophene) (P3DDT)-sorted SWNTs. Molecular dynamics simulations in explicit toluene demonstrate distinct linear or helical wrapping geometry between P(NDI2OD-T2) and different types of SWNTs, likely as a result of the strong interactions between the large aromatic core of the P(NDI2OD-T2) backbone and the hexagon path of SWNTs. By using high-mobility n-type P(NDI2OD-T2) as the sorting polymer, ambipolar SWNT transistors with better electron transport than that attained by P3DDT-sorted SWNTs are achieved. As a result, flexible negated AND and negated OR logic circuits from the same set of ambipolar transistors are fabricated, without the need for doping. The use of n-type polymers for sorting semiconducting SWNTs and achieving ambipolar SWNT transistor characteristics greatly simplifies the fabrication of flexible complementary metal-oxide-semiconductor-like SWNT logic circuits

Infective Endocarditis in Patients on Chronic Hemodialysis

295sinoneBackground: Infective endocarditis (IE) is a common and serious complication in patients receiving chronic hemodialysis (HD). Objectives: This study sought to investigate whether there are significant differences in complications, cardiac surgery, relapses, and mortality between IE cases in HD and non-HD patients. Methods: Prospective cohort study (International Collaboration on Endocarditis databases, encompassing 7,715 IE episodes from 2000 to 2006 and from 2008 to 2012). Descriptive analysis of baseline characteristics, epidemiological and etiological features, complications and outcomes, and their comparison between HD and non-HD patients was performed. Risk factors for major embolic events, cardiac surgery, relapses, and in-hospital and 6-month mortality were investigated in HD-patients using multivariable logistic regression. Results: A total of 6,691 patients were included and 553 (8.3%) received HD. North America had a higher HD-IE proportion than the other regions. The predominant microorganism was Staphylococcus aureus (47.8%), followed by enterococci (15.4%). Both in-hospital and 6-month mortality were significantly higher in HD versus non–HD-IE patients (30.4% vs. 17% and 39.8% vs. 20.7%, respectively; p < 0.001). Cardiac surgery was less frequently performed among HD patients (30.6% vs. 46.2%; p < 0.001), whereas relapses were higher (9.4% vs. 2.7%; p < 0.001). Risk factors for 6-month mortality included Charlson score (hazard ratio [HR]: 1.26; 95% confidence interval [CI]: 1.11 to 1.44; p = 0.001), CNS emboli and other emboli (HR: 3.11; 95% CI: 1.84 to 5.27; p < 0.001; and HR: 1.73; 95% CI: 1.02 to 2.93; p = 0.04, respectively), persistent bacteremia (HR: 1.79; 95% CI: 1.11 to 2.88; p = 0.02), and acute onset heart failure (HR: 2.37; 95% CI: 1.49 to 3.78; p < 0.001). Conclusions: HD-IE is a health care–associated infection chiefly caused by S. aureus, with increasing rates of enterococcal IE. Mortality and relapses are very high and significantly larger than in non–HD-IE patients, whereas cardiac surgery is less frequently performed.nonePericas J.M.; Llopis J.; Jimenez-Exposito M.J.; Kourany W.M.; Almirante B.; Carosi G.; Durante-Mangoni E.; Fortes C.Q.; Giannitsioti E.; Lerakis S.; Montagna-Mella R.; Ambrosioni J.; Tan R.-S.; Mestres C.A.; Wray D.; Pachirat O.; Moreno A.; Chu V.H.; de Lazzari E.; Fowler V.G.; Miro J.M.; Clara L.; Sanchez M.; Casabe J.; Cortes C.; Nacinovich F.; Oses P.F.; Ronderos R.; Sucari A.; Thierer J.; Altclas J.; Kogan S.; Spelman D.; Athan E.; Harris O.; Kennedy K.; Tan R.; Gordon D.; Papanicolas L.; Korman T.; Kotsanas D.; Dever R.; Jones P.; Konecny P.; Lawrence R.; Rees D.; Ryan S.; Feneley M.P.; Harkness J.; Post J.; Reinbott P.; Gattringer R.; Wiesbauer F.; Andrade A.R.; Passos de Brito A.C.; Guimaraes A.C.; Grinberg M.; Mansur A.J.; Siciliano R.F.; Varejao Strabelli T.M.; Campos Vieira M.L.; de Medeiros Tranchesi R.A.; Paiva M.G.; de Oliveira Ramos A.; Weksler C.; Ferraiuoli G.; Golebiovski W.; Lamas C.; Karlowsky J.A.; Keynan Y.; Morris A.M.; Rubinstein E.; Jones S.B.; Garcia P.; Cereceda M.; Fica A.; Mella R.M.; Fernandez R.; Franco L.; Gonzalez J.; Jaramillo A.N.; Barsic B.; Bukovski S.; Krajinovic V.; Pangercic A.; Rudez I.; Vincelj J.; Freiberger T.; Pol J.; Zaloudikova B.; Ashour Z.; El Kholy A.; Mishaal M.; Osama D.; Rizk H.; Aissa N.; Alauzet C.; Alla F.; Campagnac C.C.; Doco-Lecompte T.; Selton-Suty C.; Casalta J.-P.; Fournier P.-E.; Habib G.; Raoult D.; Thuny F.; Delahaye F.; Delahaye A.; Vandenesch F.; Donal E.; Donnio P.Y.; Flecher E.; Michelet C.; Revest M.; Tattevin P.; Chevalier F.; Jeu A.; Remadi J.P.; Rusinaru D.; Tribouilloy C.; Bernard Y.; Chirouze C.; Hoen B.; Leroy J.; Plesiat P.; Naber C.; Neuerburg C.; Mazaheri B.; Sophia Athanasia C.N.; Deliolanis I.; Giamarellou H.; Thomas T.; Mylona E.; Paniara O.; Papanicolaou K.; Pyros J.; Skoutelis A.; Papanikolaou K.; Sharma G.; Francis J.; Nair L.; Thomas V.; Venugopal K.; Hannan M.M.; Hurley J.P.; Wanounou M.; Gilon D.; Israel S.; Korem M.; Strahilevitz J.; Iossa D.; Orlando S.; Ursi M.P.; Pafundi P.C.; D'Amico F.; Bernardo M.; Cuccurullo S.; Dialetto G.; Covino F.E.; Manduca S.; Della Corte A.; De Feo M.; Tripodi M.F.; Cecchi E.; De Rosa F.; Forno D.; Imazio M.; Trinchero R.; Grossi P.; Lattanzio M.; Toniolo A.; Goglio A.; Raglio A.; Ravasio V.; Rizzi M.; Suter F.; Magri S.; Signorini L.; Kanafani Z.; Kanj S.S.; Sharif-Yakan A.; Abidin I.; Tamin S.S.; Martinez E.R.; Soto Nieto G.I.; van der Meer J.T.M.; Chambers S.; Holland D.; Morris A.; Raymond N.; Read K.; Murdoch D.R.; Dragulescu S.; Ionac A.; Mornos C.; Butkevich O.M.; Chipigina N.; Kirill O.; Vadim K.; Vinogradova T.; Edathodu J.; Halim M.; Liew Y.-Y.; Lejko-Zupanc T.; Logar M.; Mueller-Premru M.; Commerford P.; Commerford A.; Deetlefs E.; Hansa C.; Ntsekhe M.; Almela M.; Azqueta M.; Brunet M.; Castro P.; Falces C.; Fuster D.; Fita G.; Garcia- de- la- Maria C.; Garcia-Gonzalez J.; Gatell J.M.; Marco F.; Miro J.M.; Ortiz J.; Ninot S.; Pare J.C.; Pericas J.M.; Quintana E.; Ramirez J.; Rovira I.; Sandoval E.; Sitges M.; Tellez A.; Tolosana J.M.; Vidal B.; Vila J.; Anguera I.; Font B.; Guma J.R.; Bermejo J.; Bouza E.; Garcia Fernandez M.A.; Gonzalez-Ramallo V.; Marin M.; Munoz P.; Pedromingo M.; Roda J.; Rodriguez-Creixems M.; Solis J.; Fernandez-Hidalgo N.; Tornos P.; de Alarcon A.; Parra R.; Alestig E.; Johansson M.; Olaison L.; Snygg-Martin U.; Pachirat P.; Pussadhamma B.; Senthong V.; Casey A.; Elliott T.; Lambert P.; Watkin R.; Eyton C.; Klein J.L.; Bradley S.; Kauffman C.; Bedimo R.; Corey G.R.; Crowley A.L.; Douglas P.; Drew L.; Holland T.; Lalani T.; Mudrick D.; Samad Z.; Sexton D.; Stryjewski M.; Wang A.; Woods C.W.; Cantey R.; Steed L.; Dickerman S.A.; Bonilla H.; DiPersio J.; Salstrom S.-J.; Baddley J.; Patel M.; Peterson G.; Stancoven A.; Levine D.; Riddle J.; Rybak M.; Cabell C.H.Pericas, J. M.; Llopis, J.; Jimenez-Exposito, M. J.; Kourany, W. M.; Almirante, B.; Carosi, G.; Durante-Mangoni, E.; Fortes, C. Q.; Giannitsioti, E.; Lerakis, S.; Montagna-Mella, R.; Ambrosioni, J.; Tan, R. -S.; Mestres, C. A.; Wray, D.; Pachirat, O.; Moreno, A.; Chu, V. H.; de Lazzari, E.; Fowler, V. G.; Miro, J. M.; Clara, L.; Sanchez, M.; Casabe, J.; Cortes, C.; Nacinovich, F.; Oses, P. F.; Ronderos, R.; Sucari, A.; Thierer, J.; Altclas, J.; Kogan, S.; Spelman, D.; Athan, E.; Harris, O.; Kennedy, K.; Tan, R.; Gordon, D.; Papanicolas, L.; Korman, T.; Kotsanas, D.; Dever, R.; Jones, P.; Konecny, P.; Lawrence, R.; Rees, D.; Ryan, S.; Feneley, M. P.; Harkness, J.; Post, J.; Reinbott, P.; Gattringer, R.; Wiesbauer, F.; Andrade, A. R.; Passos de Brito, A. C.; Guimaraes, A. C.; Grinberg, M.; Mansur, A. J.; Siciliano, R. F.; Varejao Strabelli, T. M.; Campos Vieira, M. L.; de Medeiros Tranchesi, R. A.; Paiva, M. G.; de Oliveira Ramos, A.; Weksler, C.; Ferraiuoli, G.; Golebiovski, W.; Lamas, C.; Karlowsky, J. A.; Keynan, Y.; Morris, A. M.; Rubinstein, E.; Jones, S. B.; Garcia, P.; Cereceda, M.; Fica, A.; Mella, R. M.; Fernandez, R.; Franco, L.; Gonzalez, J.; Jaramillo, A. N.; Barsic, B.; Bukovski, S.; Krajinovic, V.; Pangercic, A.; Rudez, I.; Vincelj, J.; Freiberger, T.; Pol, J.; Zaloudikova, B.; Ashour, Z.; El Kholy, A.; Mishaal, M.; Osama, D.; Rizk, H.; Aissa, N.; Alauzet, C.; Alla, F.; Campagnac, C. C.; Doco-Lecompte, T.; Selton-Suty, C.; Casalta, J. -P.; Fournier, P. -E.; Habib, G.; Raoult, D.; Thuny, F.; Delahaye, F.; Delahaye, A.; Vandenesch, F.; Donal, E.; Donnio, P. Y.; Flecher, E.; Michelet, C.; Revest, M.; Tattevin, P.; Chevalier, F.; Jeu, A.; Remadi, J. P.; Rusinaru, D.; Tribouilloy, C.; Bernard, Y.; Chirouze, C.; Hoen, B.; Leroy, J.; Plesiat, P.; Naber, C.; Neuerburg, C.; Mazaheri, B.; Sophia Athanasia, C. N.; Deliolanis, I.; Giamarellou, H.; Thomas, T.; Mylona, E.; Paniara, O.; Papanicolaou, K.; Pyros, J.; Skoutelis, A.; Papanikolaou, K.; Sharma, G.; Francis, J.; Nair, L.; Thomas, V.; Venugopal, K.; Hannan, M. M.; Hurley, J. P.; Wanounou, M.; Gilon, D.; Israel, S.; Korem, M.; Strahilevitz, J.; Iossa, D.; Orlando, S.; Ursi, M. P.; Pafundi, P. C.; D'Amico, F.; Bernardo, M.; Cuccurullo, S.; Dialetto, G.; Covino, F. E.; Manduca, S.; Della Corte, A.; De Feo, M.; Tripodi, M. F.; Cecchi, E.; De Rosa, F.; Forno, D.; Imazio, M.; Trinchero, R.; Grossi, P.; Lattanzio, M.; Toniolo, A.; Goglio, A.; Raglio, A.; Ravasio, V.; Rizzi, M.; Suter, F.; Magri, S.; Signorini, L.; Kanafani, Z.; Kanj, S. S.; Sharif-Yakan, A.; Abidin, I.; Tamin, S. S.; Martinez, E. R.; Soto Nieto, G. I.; van der Meer, J. T. M.; Chambers, S.; Holland, D.; Morris, A.; Raymond, N.; Read, K.; Murdoch, D. R.; Dragulescu, S.; Ionac, A.; Mornos, C.; Butkevich, O. M.; Chipigina, N.; Kirill, O.; Vadim, K.; Vinogradova, T.; Edathodu, J.; Halim, M.; Liew, Y. -Y.; Lejko-Zupanc, T.; Logar, M.; Mueller-Premru, M.; Commerford, P.; Commerford, A.; Deetlefs, E.; Hansa, C.; Ntsekhe, M.; Almela, M.; Azqueta, M.; Brunet, M.; Castro, P.; Falces, C.; Fuster, D.; Fita, G.; Garcia- de- la- Maria, C.; Garcia-Gonzalez, J.; Gatell, J. M.; Marco, F.; Miro, J. M.; Ortiz, J.; Ninot, S.; Pare, J. C.; Pericas, J. M.; Quintana, E.; Ramirez, J.; Rovira, I.; Sandoval, E.; Sitges, M.; Tellez, A.; Tolosana, J. M.; Vidal, B.; Vila, J.; Anguera, I.; Font, B.; Guma, J. R.; Bermejo, J.; Bouza, E.; Garcia Fernandez, M. A.; Gonzalez-Ramallo, V.; Marin, M.; Munoz, P.; Pedromingo, M.; Roda, J.; Rodriguez-Creixems, M.; Solis, J.; Fernandez-Hidalgo, N.; Tornos, P.; de Alarcon, A.; Parra, R.; Alestig, E.; Johansson, M.; Olaison, L.; Snygg-Martin, U.; Pachirat, P.; Pussadhamma, B.; Senthong, V.; Casey, A.; Elliott, T.; Lambert, P.; Watkin, R.; Eyton, C.; Klein, J. L.; Bradley, S.; Kauffman, C.; Bedimo, R.; Corey, G. R.; Crowley, A. L.; Douglas, P.; Drew, L.; Holland, T.; Lalani, T.; Mudrick, D.; Samad, Z.; Sexton, D.; Stryjewski, M.; Wang, A.; Woods, C. W.; Cantey, R.; Steed, L.; Dickerman, S. A.; Bonilla, H.; Dipersio, J.; Salstrom, S. -J.; Baddley, J.; Patel, M.; Peterson, G.; Stancoven, A.; Levine, D.; Riddle, J.; Rybak, M.; Cabell, C. H