Search Results - (Author, Cooperation:L. Parenteau)
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1Latest Papers from Table of Contents or Articles in PressP. Penaloza-MacMaster ; D. L. Barber ; E. J. Wherry ; N. M. Provine ; J. E. Teigler ; L. Parenteau ; S. Blackmore ; E. N. Borducchi ; R. A. Larocca ; K. B. Yates ; H. Shen ; W. N. Haining ; R. Sommerstein ; D. D. Pinschewer ; R. Ahmed ; D. H. Barouch
American Association for the Advancement of Science (AAAS)
Published 2015Staff ViewPublication Date: 2015-01-17Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: Adaptive Immunity ; Animals ; Antibodies, Viral/immunology ; Antigens, Viral/immunology ; Arenaviridae Infections/*immunology/virology ; CD4-Positive T-Lymphocytes/*immunology ; CD8-Positive T-Lymphocytes/immunology ; Cytokines/blood ; Epitopes, T-Lymphocyte/immunology ; Immune System Diseases/*etiology/immunology/pathology ; Immunologic Memory ; Inflammation/*etiology/immunology/pathology ; Lymphocytic choriomeningitis virus/*immunology/physiology ; Mice, Inbred C57BL ; Multiple Organ Failure/etiology ; Vaccination ; Viral Load ; Viral Vaccines/*adverse effects/*immunology ; Virus ReplicationPublished by: -
2Latest Papers from Table of Contents or Articles in PressD. H. Barouch ; G. Alter ; T. Broge ; C. Linde ; M. E. Ackerman ; E. P. Brown ; E. N. Borducchi ; K. M. Smith ; J. P. Nkolola ; J. Liu ; J. Shields ; L. Parenteau ; J. B. Whitney ; P. Abbink ; D. M. Ng'ang'a ; M. S. Seaman ; C. L. Lavine ; J. R. Perry ; W. Li ; A. D. Colantonio ; M. G. Lewis ; B. Chen ; H. Wenschuh ; U. Reimer ; M. Piatak ; J. D. Lifson ; S. A. Handley ; H. W. Virgin ; M. Koutsoukos ; C. Lorin ; G. Voss ; M. Weijtens ; M. G. Pau ; H. Schuitemaker
American Association for the Advancement of Science (AAAS)
Published 2015Staff ViewPublication Date: 2015-07-04Publisher: American Association for the Advancement of Science (AAAS)Print ISSN: 0036-8075Electronic ISSN: 1095-9203Topics: BiologyChemistry and PharmacologyComputer ScienceMedicineNatural Sciences in GeneralPhysicsKeywords: AIDS Vaccines/*immunology ; Adenovirus Vaccines/*immunology ; Adoptive Transfer ; Animals ; Antibodies, Neutralizing/immunology ; Female ; Gene Products, env/*immunology ; Gene Products, gag/immunology ; Gene Products, pol/immunology ; Genetic Vectors/immunology ; HIV-1/*immunology ; Histocompatibility Antigens Class I/genetics/immunology ; Immunization, Secondary ; Macaca mulatta ; Male ; SAIDS Vaccines/*immunology ; Simian Acquired Immunodeficiency Syndrome/*prevention & control ; Simian Immunodeficiency Virus/immunologyPublished by: -
3Latest Papers from Table of Contents or Articles in PressJ. B. Whitney ; A. L. Hill ; S. Sanisetty ; P. Penaloza-MacMaster ; J. Liu ; M. Shetty ; L. Parenteau ; C. Cabral ; J. Shields ; S. Blackmore ; J. Y. Smith ; A. L. Brinkman ; L. E. Peter ; S. I. Mathew ; K. M. Smith ; E. N. Borducchi ; D. I. Rosenbloom ; M. G. Lewis ; J. Hattersley ; B. Li ; J. Hesselgesser ; R. Geleziunas ; M. L. Robb ; J. H. Kim ; N. L. Michael ; D. H. Barouch
Nature Publishing Group (NPG)
Published 2014Staff ViewPublication Date: 2014-07-22Publisher: Nature Publishing Group (NPG)Print ISSN: 0028-0836Electronic ISSN: 1476-4687Topics: BiologyChemistry and PharmacologyMedicineNatural Sciences in GeneralPhysicsKeywords: Animals ; Anti-Retroviral Agents/administration & dosage/pharmacology/therapeutic use ; Carrier State/drug therapy/virology ; DNA, Viral/analysis/biosynthesis/blood ; Disease Models, Animal ; Female ; Kinetics ; Macaca mulatta/immunology/*virology ; Male ; Proviruses/genetics ; RNA, Viral/blood ; Rectum/virology ; Simian Acquired Immunodeficiency Syndrome/drug therapy/immunology/*virology ; Simian Immunodeficiency Virus/drug effects/*growth & ; development/immunology/physiology ; Time Factors ; Treatment Failure ; *Viral Load/drug effects ; Viremia/drug therapy/*virology ; Virus Replication/drug effectsPublished by: -
4Articles: DFG German National LicensesRowntree, P. ; Parenteau, L. ; Sanche, L.
College Park, Md. : American Institute of Physics (AIP)
Published 1991Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: Low energy (0–12 eV) electron impact on condensed amorphous H2O and D2O films is shown to induce electron stimulated desorption of H− and D−, respectively, via dissociative electron attachment. The onsets for H− and D− detection are at 5.5 eV, with a maximum yield for anion desorption at ∼7.4 eV. The kinetic energy distributions of the desorbing anions are peaked near 0 eV, indicating that the anions suffer post-dissociation collisions at or near the surface, with a large probability of anion trapping on the surface. The present results provide direct information on the dissociation products, prior to the interferences of subsequent reaction processes in the condensed film.Type of Medium: Electronic ResourceURL: -
5Articles: DFG German National LicensesStaff View
ISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: We report the formation of the anion–atom complexes ArO− and ArCl− by electron stimulated desorption from multilayer argon films containing O2, N2O, and Cl2 molecules.Type of Medium: Electronic ResourceURL: -
6Articles: DFG German National LicensesAzria, R. ; Parenteau, L. ; Sanche, L.
College Park, Md. : American Institute of Physics (AIP)
Published 1988Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: The formation of O− ions via dissociative attachment (DA) in electron stimulated desorption from condensed CO is reported. The 2Π states of CO− previously observed in the gas phase and CO− states with the forbidden symmetry Σ− are involved below and above 13 eV, respectively, in the DA processes. Measurements of the kinetic energy of O− ions indicate that they suffer post dissociation interactions with the neighboring CO molecules before leaving the solid.Type of Medium: Electronic ResourceURL: -
7Articles: DFG German National LicensesStaff View
ISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: Desorption of O− and OH− ions induced by low-energy (4–20 eV) electron impact on O2 and hydrocarbon molecules (CnH2n+2, n=5 and 8; CnH2n, n=2, 3, and 4) coadsorbed on Pt is reported. The magnitude of the O− and OH− signals is investigated as a function of incident electron energy and substrate coverage. Beyond monolayer coverage, results are provided for two types of coadsorption: a single hydrocarbon layer physisorbed on a multilayer O2 film and a multilayer film containing 25% volume O2 mixed with hydrocarbon molecules. For all experiments, the OH− yield function can be correlated with that of the O− signal from pure O2 and hydrocarbon–O2 mixture films. This result indicates that the OH− ions are produced by the abstraction reactions O−+CnH2n+2→OH−+CnH2n+1 and O−+CnH2n→OH−+CnH2n−1 where O− ions are generated by the dissociative attachment reaction e+O2 (3∑−g)→O−2 (2∏u,2∑+g,2∑+u)→O− (2P)+O(3P,1D). The observed reaction efficiency for OH− formation, defined as the ratio of the OH− intensity to that of O−, is found to increase with coverage of the substrate by C4H8–O2 and C5H12–O2 mixtures. It reaches values of 3% and 8%, respectively, above 3 monolayers for incident electrons of 13 eV. The energetics involved in those reactions as well as the behavior of the OH− intensity as a function of incident electron energy and coverage strongly suggest that OH− arises from dissociation of the intermediate quasi-bound anions CnH2n+2 O− and CnH2n O− into the limits OH−+CnH2n±1.Type of Medium: Electronic ResourceURL: -
8Articles: DFG German National LicensesSanche, L. ; Parenteau, L. ; Cloutier, P.
College Park, Md. : American Institute of Physics (AIP)
Published 1989Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: Desorption of the ions O−, O−2,O−3 (and/or O2⋅O−) induced by electron impact on pure O2 multilayer films and Ar, Kr, and Xe matrix films containing O2 is reported. In addition to these anions, the ionic complexes M⋅O− (M=Ar and Kr) are also observed to desorb from Ar and Kr matrices, respectively. In the range 4–16 eV, the incident electron energy (Ei) dependence of the yields (i.e., the yield functions) of all the diatomic and triatomic anions exhibit features which can be correlated with the O− yield function; indicating that, these anions are produced by dissociative attachment reactions whose first step involves the formation of O−2 quasibound states. From analysis of all yield functions and variations of the anion yields as a function of O2 concentration in the matrices, we find that the simplest dissociative transient state, which can propel in vacuum an M⋅O− or O2⋅O− ion, must have the configuration M⋅O2⋅O−*2. To explain the formation of O−2 and O−3 ions below Ei(approximately-equal-to)6 eV, the existence of an electronically excited O−4 state decaying into the limits O−2+O2 and O−3+O must be postulated. At higher energies, O−2 can be formed by the reaction of O− (produced by dissociating O−2 states) with other O2 molecules (e.g., O−+O2→O−3→O−2+O). Both transient anion, M⋅O2O−*2,O−*4 result from initial electron capture by an O2 molecule in a dimeric configuration.Type of Medium: Electronic ResourceURL: -
9Articles: DFG German National LicensesAkbulut, M. ; Madey, T. E. ; Parenteau, L. ; Sanche, L.
College Park, Md. : American Institute of Physics (AIP)
Published 1996Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: We have studied electron stimulated desorption (ESD) of negative ions from PF3 molecules adsorbed on a Pt substrate over a wide electron energy range (0–175 eV). ESD from adsorbed PF3 gives rise to several negative ion fragments: F− (predominantly), F−2, P−, and PF−. The F− yield produced in the electron energy range 0–15 eV proceeds via dissociative electron attachment (DEA); the F− yield exhibits a peak around 11.5 eV with an onset around 7.5 eV. At electron energies above ∼15 eV, F− ions are produced via dipolar dissociation (DD). We have found that the F− ions produced from a 1 ML PF3/Pt surface via a DEA process with 11.5 eV electron impact desorb with a peak kinetic energy of ∼0.7 eV, while the F− ions generated via DD by 175 eV electron impact desorb with a peak kinetic energy of ∼1.2 eV. The F−2 yield curve also shows a peak at ∼11.5 eV; the onset of the F−2 yield from adsorbed PF3 is ∼9 eV. The F−2 yield in the electron range 9–15 eV is initiated via DEA. The P− signal from PF3 adsorbed on Pt has an onset at ∼16 eV. We have identified some possible DEA and DD processes leading to desorption of negative ions from adsorbed PF3. We suggest that Rydberg core-excited (1-hole, 2-electron) transient anion states of PF3, formed by capture of low energy electrons, dissociate to produce the F− and F−2 ions for E(e)〈15 eV. © 1996 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
10Articles: DFG German National LicensesHuels, M. A. ; Parenteau, L. ; Sanche, L.
College Park, Md. : American Institute of Physics (AIP)
Published 1994Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: We present measurements of O− electron stimulated desorption yields obtained under identical experimental conditions from 0.15 monolayers (ML) of O2 deposited onto disordered substrates consisting of 4 ML of either Kr, Xe, C2H6, C2H4, N2O, CH3Cl, or H2O, all condensed on Pt (polycrystalline). The resulting O− yield functions, for incident electron energies below 20 eV, are compared to that obtained from the O2/Kr solid; this allows us to assess the order of magnitude effects of the local substrate environment on dissociative electron attachment (DEA) via the 2Πu and gas phase forbidden 2Σ+g,u resonances of O−2. We note that, in addition to electron energy losses in the substrate prior to DEA to O2 and post-dissociation interactions of the O− with the substrate molecules, charge or energy transfer from the O−2 transient anion to a substrate molecule, and capture of the incident electron into a dissociative anion resonance of the substrate molecule may contribute to a reduced O− yield from the physisorbed O2. In the case of O2 deposited on amorphous ice, we find that the O− signal from DEA to O2 is completely absent for electron energies below 14 eV; we attribute this to a complete quenching of the dissociative O−2(2Πu, 2Σ+) resonances by the adjacent water molecules.Type of Medium: Electronic ResourceURL: -
11Articles: DFG German National LicensesHuels, M. A. ; Parenteau, L. ; Cloutier, P. ; Sanche, L.
College Park, Md. : American Institute of Physics (AIP)
Published 1995Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: We report electron stimulated desorption (ESD) measurements of O− yields produced by dissociative electron attachment (DEA) to physisorbed CO2. The molecules are condensed at about 17–20 K on polycrystalline Pt, either as pure multilayer films, or in submonolayer (ML) quantities onto thick rare gas substrates. For the pure disordered multilayer solids, we observe four peaks in the O− yield function at incident electron energies, E(e), of about 4.1, 8.5, 11.2, and 15 eV. The lowest two are assigned, respectively, to the 2Πu and 2Πg resonance states of CO−2, which dissociate into O−(2P)+CO(X 1Σ+), and are known to dominate the gas phase DEA O− production cross section for E(e)≤20 eV. Measurements of ESD CO* metastable yields from similar CO2 multilayer solids on Pt(111), also presented here, suggest that the 11.2 and 15 eV O− peaks are associated with the manifold of close-lying CO2*− states which dissociate into O−(2P)+CO* (a 3Π, a′ 3Σ+, or d 3Δ). For 0.15 ML of CO2 physisorbed on 20 ML thick rare gas substrate films significant sharp enhancements (fwhm ≤0.5 eV) are observed in the ESD O− yields at about 0.3–0.4 eV below the lowest substrate exciton energy. These enhancements are attributed to a coupling of the (electron plus exciton) core-excited anion resonances of the rare gas atoms to the dissociative Rydberg anion states of the coadsorbed CO2 at the solid's surface. This is followed by a transfer of the charge and excitation energy to the coadsorbate. © 1995 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
12Articles: DFG German National LicensesRowntree, P. ; Sanche, L. ; Parenteau, L. ; Meinke, M. ; Weik, F. ; Illenberger, E.
College Park, Md. : American Institute of Physics (AIP)
Published 1994Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: Dissociative electron attachment (DEA) processes have been observed and characterized for submonolayer and multilayer quantities of CCl4, CDCl3, CD2Cl2, CH3Cl, and CH3Br adsorbed on metallic substrates and submonolayer quantities adsorbed onto Kr spacer layers. Anion yields (Br−, Cl−, H−, D−) are reported for incident electron energies from 0 to 12 eV; no desorbing polyatomic anion fragments were detected. The results are compared to the gas-phase DEA analogs and demonstrate the perturbations on the DEA process that are introduced by the presence of the highly polarizable environment (molecular solid+metal substrate). We also report the first observation of H−(D−) produced by DEA of halomethanes containing hydrogen (deuterium).Type of Medium: Electronic ResourceURL: -
13Articles: DFG German National LicensesAzria, R. ; Parenteau, L. ; Sanche, L.
College Park, Md. : American Institute of Physics (AIP)
Published 1987Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: Energy analysis of Cl− ions produced by dissociative attachment in electron stimulated desorption from Cl2 condensed on a platinum substrate is reported. The electron energy dependence of the Cl− signal exhibits two peaks around 2 and 5 eV which arise, respectively, from the 2Πg and 2Πu core-excited Cl−@B|2 resonant states. At higher Cl2 coverages, a third peak is observed around 11.5 eV. From kinetic energy distributions, it is possible to ascribe this latter peak to Cl− ions formed via the 2Πu resonance by electrons which have suffered energy losses through the excitation of low-lying electronic states of molecular chlorine. In the energy range of the 2Πu Cl−*2 resonance, we observe that multiple scattering processes are also important and that the curve representing the kinetic energy of Cl− ions formed via a single scattering process as a function of incident electron energy is a straight line with a slope 1/2. This indicates that the chlorine lattice is not involved in the dissociation dynamics.Type of Medium: Electronic ResourceURL: -
14Articles: DFG German National LicensesAkbulut, M. ; Madey, T. E. ; Parenteau, L. ; Sanche, L.
College Park, Md. : American Institute of Physics (AIP)
Published 1996Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: We have studied electron stimulated desorption (ESD) of positive ions from PF3 molecules adsorbed on a Pt substrate over a wide electron energy range (0–175 eV). Electron bombardment of 1 ML PF3 adsorbed on the Pt surface gives rise mainly to an F+ signal, whereas ESD from 6 ML thick PF3 film (thick PF3 layer) leads to P+, PF+, and PF+2 signals, in addition to F+. We find that the onset for F+ desorption from the 1-ML PF3/Pt is at ∼26.5 eV, while the F+ threshold from the thick PF3 layer is ∼28.5 eV. The P+ appearance potential from the thick PF3 layer is ∼23 eV. The ESD F+ ion energy distribution has a peak energy of ∼4 eV for all electron impact energies and a full width at half maximum (FWHM) of ∼3 eV. The P+ ions desorb with a peak energy of ∼2 eV under 55 eV electron impact; the FWHM of the P+ energy distribution is ∼2 eV. We suggest that the near threshold P+ formation from PF3 corresponds to the excitations of the 6a1 level, while the F+ threshold for adsorbed PF3 on the Pt surface is due to the excitation of the F 2s level. Our results suggest that beyond near threshold ((approximately-greater-than)32 eV), the excitation of the F 2s level also contributes significantly to the formation of P+ and PF+ ions from adsorbed PF3. © 1996 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
15Articles: DFG German National LicensesBass, A. D. ; Parenteau, L. ; Weik, F. ; Sanche, L.
College Park, Md. : American Institute of Physics (AIP)
Published 2000Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: We have measured for the 0–20 eV incident energy range, the low-energy electron transmission (LEET) spectra and electron stimulated desorption (ESD) yields of H− from pure films of n-hexane and ethyl-benzene from 20 K to sublimation. The ESD yields from both dissociative electron attachment and dipolar dissociation initially increase as the films are heated. This effect is attributed to the collapse of pores within the films. For n-hexane, a marked decrease in ESD yields is observed at film temperatures ≥80 K, which correlates to the onset of crystallization as evidenced in LEET spectra. This decrease in anion yield is associated with the formation of a well-defined band structure that reduces the time period an excitation and/or electron resides on a particular molecule. This behavior in the ESD yields from ethyl-benzene films is not observed prior to sublimation in agreement with LEET spectra which show negligible change with film temperature indicating that there is no change of phase prior to sublimation (i.e., the film remains amorphous at all temperatures). © 2000 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
16Articles: DFG German National LicensesBass, A. D. ; Parenteau, L. ; Huels, M. A. ; Sanche, L.
College Park, Md. : American Institute of Physics (AIP)
Published 1998Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: Anion desorption stimulated by the impact of 0–20 eV electrons on O2/hydrocarbon mixed films is reported. It is shown that part of the H−, OH−, CH−, and CH2〈sup ARRANGE="STAGGER"〉− desorption yields from O2/hydrocarbon films is the result of reactive scattering of O− fragments produced via dissociative electron attachment (DEA) in the alkane and alkene thin films. These results support the interpretation that the DEA O− react with the hydrocarbon molecules to form a transient molecular anion complex which, in addition to autodetachment, may decay by dissociation into various anion and neutral fragments, and thus cause chemical modification of the solid. © 1998 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
17Articles: DFG German National LicensesBass, A. D. ; Parenteau, L. ; Weik, F. ; Sanche, L.
College Park, Md. : American Institute of Physics (AIP)
Published 2001Staff ViewISSN: 1089-7690Source: AIP Digital ArchiveTopics: PhysicsChemistry and PharmacologyNotes: We investigate the effects of the geometrical structure (phase and porosity) of multilayer benzene films on the desorption of O− induced by 2–20 eV electron impact on varying quantities of absorbed O2. Differences in the yield of O− from O2 doped amorphous and crystalline benzene films are attributed to the ability of O2 to diffuse into the amorphous solid via pores and defects formed during its deposition at 20 K. In contrast, diffusion into crystalline benzene is limited and deposited O2 molecules remain at the surface of the film. Thermal desorption measurements support this analysis. The data are also compared with results of similar experiments for O2 on water. While it is apparent that some of the variation in O− yield observed from ice films is similarly related to morphology, a substantial suppression of the O− yield is likely to result from energy loss by electrons prior to dissociation. Quenching of intermediate O2− states by water ice may also contribute to this suppression in the range 5–12 eV. © 2001 American Institute of Physics.Type of Medium: Electronic ResourceURL: -
18Articles: DFG German National LicensesStaff View
ISSN: 0009-2614Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyPhysicsType of Medium: Electronic ResourceURL: -
19Articles: DFG German National LicensesStaff View
ISSN: 0009-2614Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyPhysicsType of Medium: Electronic ResourceURL: -
20Articles: DFG German National LicensesStaff View
ISSN: 0009-2614Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002Topics: Chemistry and PharmacologyPhysicsType of Medium: Electronic ResourceURL: