647 research outputs found
Excimers Beyond Pyrene: A Far-Red Optical Proximity Reporter and its Application to the Label-Free Detection of DNA
No full textA family of organic chromophores that, like pyrene, forms emissive excimers is reported. Their chemical and photophysical properties are superior to pyrene for the design of chemo- and biosensors. Unlike hydrophobic pyrene, which requires excitation by cell-damaging UV irradiation, these polar dyes absorb strongly in the visible range, and their excimers emit brightly in the red to far-red region of the electromagnetic spectrum. The intensity of the emission signal is greatly increased upon formation of a preassociated dimer that is triggered upon aggregation or crystallization. In demonstration of the potential of this new family of excimer-forming dyes, a probe that is capable of detecting label-free DNA in water down to 10 pm and also doubles as a visualization agent for DNA in gel electrophoresis is reported
Air-Liquid Interfacial Self-Assembly of Non-Amphiphilic Poly(3-hexylthiophene) Homopolymers
No full textHere, we demonstrate that the self-assembly of poly(3-hexylthiophene) (P3HT) at the air-water interface can lead to free-standing films of densely packed P3HT nanowires. Interfacial self-assembly on various liquid subphases, such as water, diethylene glycol, and glycerol, indicates that the-viscosity of the subpliase is an important factor for the formation of well-ordered nanostructures. The thin-film morphology is also sensitive to the concentration of P3HT, its molecular weight (MW), and the presence of oxidative defects. The densely packed nanowire films can be easily transferred to solid substrates for device applications. The ultrathin films of P3HT prepared by the interfacial assembly showed significantly higher hole mobility (similar to 3.6 X 10(-2) cm(2)/V s) in a field-effect transistor than comparably thin spin-cast films. This work demonstrates that the air liquid interfacial assembly is not limited to amphiphilic polymers and can, under optimized conditions, be applied to fabricate ultrathin films of widely used conjugated polymers with controlled morphologies
Enantioselective extraction of unprotected amino acids coupled with racemization
No full textScalable and economical methods for the production of optically pure amino acids, both natural and unnatural, are essential for their use as synthetic building blocks. Currently, enzymatic dynamic kinetic resolution (DKR) underpins some of the most effective processes. Here we report the development of enantioselective extraction coupled with racemization (EECR) for the chirality conversion of underivatized amino acids. In this process, the catalytic racemization of amino acids in a basic aqueous solution is coupled with the selective extraction of one enantiomer into an organic layer. Back-extraction from the organic layer to an acidic aqueous solution then completes the deracemization of the amino acid. The automation of the EECR process in a recycling flow reactor is also demonstrated. Continuous EECR is made possible by the sterically hindered chiral ketone extractant 5, which prevents the coextraction of the copper racemization catalyst because of its nonplanar geometry. Furthermore, the extractant 5 unexpectedly forms imines with amino acids faster and with greater enantioselectivity than less bulky derivatives, even though 5 cannot participate in intramolecular resonance-assisted hydrogen bonding. These features may allow EECR to challenge the preponderance of enzymatic DKR in the production of enantiomerically enriched amino acids. © 2021, The Author(s)
Heavy Ions Irradiation Effects On Magnetization Of Tl2ba2cacu2o8 And Tlba2cacu2o7 Single Crystals
No full textFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Magnetization measurements were performed as a function of magnetic field and time in Tl2Ba2CaCu2O8 and TlBa2CaCu2O7 single crystals to study the effects of high energy Xe ion irradiation. The effective pinning energies at 6 K and 40 K have been evaluated from magnetic relaxation measurements. The activation energies are hardly changed after irradiation. The study of magnetization hysteresis shows that an irradiation fluence of 2 × 1011 ions cm-2 enhanced hysteresis at 6 K in both crystals. But a fluence of 1012 ions cm-2 was detrimental for the 2212 sample which is the most sensitive to heavy ion irradiation damage in the Tl-cuprate family. The magnetic hysteresis at 70 K after irradiation is more drastically increased than at 6 K. This spectacular modification is interpreted by a recovery of the 3D character of the flux line lattice. © 1992.13427928507/57630-5; FAPESP; Simons Foundation; 2013/09850-7; FAPESP; Simons Foundation; DMR-1005751; NSF; Simons Foundation; PHYS-1066293; NSF; Simons Foundation; SF; Simons FoundationFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Umezawa, Crabtree, Liu, Weber, Kwok, Nunez, Moran, Claus, (1987) Phys. Rev. B, 36, p. 7151van Dover, Gyorgy, White, Schneemeyer, Felder, Wasczak, (1990) Appl. Phys. Lett., 56, p. 2681Civale, Warwick, McElfresh, Worthington, Malozemoff, Holzberg, Thompson, Kirk, (1990) Phys. Rev. Lett., 65, p. 1164Kritscha, Sauerzopf, Weber, Crabtree, Chang, Jiang, Flux Pinning Enhancement and Shift of the Irreversibility Line by Fast Neutron Irradiation of Single Crystal Bi2Sr2CaCu2O8 (1990) Europhysics Letters (EPL), 12, p. 179Vichery, Rullier-Albenque, Pascard, Konczylowski, Kormann, Favrot, Collin, (1989) Physica C, 159, p. 697Bourgault, Bouffard, Toulemonde, Groult, Provost, Studer, Nguyen, Raveau, (1989) Phys. Rev. B, 39, p. 6549Bourgault, Hervieu, Bouffard, Groult, Raveau, (1989) Nucl. Instrum. Methods B, 42, p. 61Hardy, Groult, Hervieu, Provost, Raveau, Bouffard, (1991) Nucl. Instrum. Methods B, 54, p. 472Venturini, Barbour, Ginley, Baughman, Morosin, (1990) Appl. Phys. Lett., 56, p. 2456Osborn, (1945) Phys. Rev., 67, p. 351Yeshurun, Malozemoff, Holtzberg, Dinger, (1988) Phys. Rev. B, 38, p. 11828Campbell, Fruchter, Cabanel, (1990) Phys. Rev. Lett., 64, p. 1561Xu, Suenaga, Moodenbaugh, Welch, (1989) Phys. Rev. B, 40, p. 10882Stollman, Dam, Emmen, Pankert, (1989) Physica C, 161, p. 444Beasley, Labush, Welb, (1969) Phys. Rev., 181, p. 682Martin, Maignan, Provost, Michel, Hervieu, Tournier, Raveau, (1990) Physica C, 168, p. 8Hardy, Groult, Provost, Hervieu, Raveau, Bouffard, (1991) Physica C, 178, p. 255Raveau, Hervieu, Michel, Provost, (1989) Mater. Sci. Eng., 109 A, p. 281Hardy, Hervieu, Groult, Provost, (1991) Radiation Effects and Defects in Solids, , in the pressKopylev, Schegolev, Togonidze, Magnetization curves and low critical fields of Tl2Ba2CaCu2Ox single crystals (1989) Physica C: Superconductivity, 162-164, p. 1143Kopylev, Koshelev, Schegolev, Togonidze, The role of surface effects in magnetization of high-Tc superconductors (1990) Physica C: Superconductivity, 170, p. 291Kes, Aarts, van den Berg, van der Beek, Mydoch, (1989) Supercond. Sci. Technol., 1, p. 242Palstra, Batlogg, Scheemeyer, Wasczak, (1991) Phys. Rev. B, 43, p. 3756de Rango, Giordanengo, Tournier, Sulpice, Chaussy, Deutscher, Genicon, Raveau, The « irreversibility line » of Bi2-xPbxSr2Ca2Cu3O10 : a possible breakdown of an intrinsic proximity effect (1989) Journal de Physique, 50, p. 2857Raveau, Michel, Provost, Hervieu, The nature and the role of rock salt-type layers in superconductive layered copper oxides (1990) Solid State Ionics, 40-41, p. 785. , 1st ednV.Z. Kresin, S.A. Wolf and G. Deutscher, PreprintV. Hardy, J. Provost, D. Groult, M. Hervieu, B. Raveau, S. Durcok, E. Pollert, J.-C. Frison, J.-P. Chaminade and M. Pouchard, Physica C, accepted for publicationKonczykowski, Rullier-Albenque, Yacoby, Shaulov, Yeshurun, Lejay, (1991) Phys. Rev. B, 44, p. 7167Civale, Marwick, Worthington, Kirk, Thompson, Krusin-Elbaum, Sun, Holtzberg, (1991) Phys. Rev. Lett., 67, p. 64
Interprofessional collaboration: Opportunities for therapeutic recreation to shine
No full textNot peer reviewedInterprofessional collaborationConference presentation delivered at the Canadian Therapeutic Recreation Association annual conference, Kelowna, British Columbia (2017). The session described the collective transformational experiences of students attending practicum and intership in rural Uganda
Management of IIH Patients Who Present With Grade V Papilledema
No full textFrisén grade III-V papilledema predicts worse visual outcomes in patients with idiopathic intracranial hypertension (IIH). High-grade papilledema is associated with subretinal fluid, chorioretinal folds, and reduced acuity, but good prognosis. Surgical therapy is recommended for fulminant IIH (significant visual field constriction or acuity reduction within 4 weeks of symptom onset), but this recommendation is sometimes applied loosely to severe papilledema. We studied a retrospective series of IIH patients who presented with grade V papilledema and compared medical and surgical management
State v. Durepo: Toward a Principled Maine Version of the Impeachment Exception to the Exclusionary Rule
No full textAs one might have anticipated, the broad substantive mandates of the major Warren Court exclusionary rule decisions have not been left completely intact by later Supreme Court decisions. Instead, the scope of the evidentiary exclusionary doctrine established by the Warren Court has been significantly narrowed by later Supreme Court decisions that have created numerous exceptions to the general command of the exclusionary rule that evidence obtained through unconstitutional means is inadmissible in a criminal trial. Although some members of the present Court argue that the exceptions to the exclusionary rule are consistent with the purposes of the rule, and therefore legitimate, other Justices argue that some of the exceptions to the exclusionary rule erode the constitutional rights of criminal defendants. Two cases which characterize the movement toward more restrictive application of the exclusionary rule are Harris v. New York and United States v. Havens. These cases generated an exception to the exclusionary rule by allowing the introduction of unconstitutionally obtained evidence at trial for the purpose of impeaching a criminal defendant\u27s credibility, notwithstanding the inadmissibility of the evidence in the prosecution\u27s case in chief. In State v. Durepo, the Maine Supreme Judicial Court, sitting as the Law Court, applied the settled federal law of Harris and Havens and affirmed the attempted murder and aggravated assault convictions of Thomas Durepo, whose suppressed pre-trial statements were used to impeach his credibility at trial. Justice Wathen, writing for the majority, concluded that the Law Court was bound by Harris and Havens because Durepo did not raise any state constitutional issues on appeal. Furthermore, in dicta the majority opinion explicitly endorsed the underlying rationale of the Harris-Havens rule. Dissenting in part, Justice Glassman argued that as a matter of state constitutional law statements suppressed under Miranda should not be admissible in Maine courts for any purpose. In a concurring opinion joined by Justice Nichols, Justice Roberts agreed with the majority that absent a violation of the Maine Constitution, the Law Court could not reject Harris-Havens on state constitutional grounds. However, the concurring justices were unwilling to join the majority\u27s endorsement of the Harris-Havens rationale
Rome souterraine : résumé des découvertes de M. de Rossi dans les catacombes romaines, et en particulier dans le cimetière de Calliste /
No full text"Histoire littéraire de Rome souterraine": p. 1-30.Errata: p. [1]-[2] (second series).Includes bibliographical references.Mode of access: Internet.Library's copy 2 bound in marbled paper-covered boards; leather spine with gilt tooling; bookplate of G. v. Bouffard on front pastedown.Library's copy 1 bound in marbled paper-covered boards; red leather spine and corners; spine gilt tooled
Preparation of Conjugated Block Copolymers by Cross Metathesis Synthetic Explorations Toward the Preparation of Less E-Rich Block Copolymers that Comprise Polythiophenes
No full textIn chapter I, we presented the alternative synthetic method to prepare block copolymer for supplementing drawbacks of existing way, which are limited yields, slow kinetics, and undesirable side reactions like homo coupling. We prepared both poly(3-hexylthiophene)s by GRIM method and several kinds of poly ethylene glycol acrylates (PEGs) as each block for diblock copolymer. And then, we synthesized block copolymers using olefin metathesis with each two blocks.
We introduced 3 kinds of synthesized PEG acrylate and 1 other existing acrylate, which is poly propylene glycol (PPG) acrylate. With these 3 of them, we prepared 3 different diblock copolymers, P3HT-b-PEG series.
We also proceeded in air-liqiud interface self assembly (ALISA) by the help of Prof. So-Jung Park’s group, and obtained well-aligned uniform nanowire arrays from TEM results.
In chapter II, we designed a new conjugated polymer which could overcome disadvantages of existing poly(3-hexylthiophene)s. For a synsthesis of the new conjugated polymer, we prepared 3 different thienopyrroledione (TPD) monomer. We tried 9 kinds of polymerization with TPD monomers including GRIM, Yamamoto, and other kinds of Zn metalations.
;챕터1에서는, 제한적인 수득률과, 낮은 반응속도, 그리고 원하지 않는 homo coupling 과 같은 부반응의 발생 등 이러한 기존 방법의 단점을 보완하기 위하여 block copolymer를 합성하는 다른 대안책의 방법을 소개하였다. 우리는 diblock polymer의 각각의 block 으로 GRIM 방법을 이용하여 poly(3-hexylthiophene)을 합성하고, 몇몇 다른 종류의 poly ethylene glycol (PEG) acrylate들을 준비하였다. 그리고 나서, 준비한 두 block들로 olefin metathesis를 이용하여 block copolymer를 합성하였다.
우리는 기존에 이미 있는 poly propylene glycol (PPG) 외에 3가지 종류의 합성된 PEG acrylate를 소개하였다. 그 중 3가지의 acrylate를 가지고, 우리는 3가지의 다른 diblock copolymer인 P3HT-b-PEG 시리즈를 합성하였다.
또한, 박소정 교수님 연구진의 지원으로, 만들어진 P3HT-b-PEG block copolymer를 사용한 air-liqiud interface self assembly (ALISA)를 진행하였다.
챕터2에서는, 우리는 기존 Poly(3-hexylthiophene)의 단점을 극복할 수 있는 새로운 conjugated polymer를 설계하였다. 이 새로운 conjugated polymer의 합성을 위해서, 3가지의 다른 thienopyrroledione (TPD) monomer를 준비하였다. 그리하여, 이 3가지의 TPD monomer를 가지고 GRIM, Yamamoto, 그리고 다른 여러 Zn metalation을 포함한 9가지의 다른 조건하에서 polymerization을 시도하였다.Chapter I 2
I. Introduction 3
II. Results and Discussions 13
A. Preparation of allyl end-capped P3HT 13
B. Preparation of PEG acrylates 18
C. Joining the polymer blocks by cross metathesis using the Grubbs catalyst 19
III. Conclusions 27
IV. Experimental methods 28
V. References 35
VI. Appendices 37
Chapter II 40
I. Introduction 41
II. Results and Discussions 44
III. Conclusions 57
IV. Experimental methods 58
V. References 65
VI. Appendices 67
Abstract (in Korean) 7
Le manuscrit de Kreuznach dans la GEME
No full textLa Grande Edition Marx Engels (GEME) s'enrichit d'un nouveau volume. La Contribution à la critique à la philosophie du droit de Hegel fait l'objet d'une nouvelle traduction, signée V. Béguin, A. Bouffard, P. Guerpillon et F. Nicodème. Cette traduction du manuscrit de Kreuznach est accompagnée d'une dense introduction, de tous les passages de Hegel glosés par Marx, et d'une postface du philosophe J.F. Kervégan. = https://editionssociales.fr/index.php/2018/08/29/karl-marx-contribution-a-la-crit..
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