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He C, Jones RR. Active Suppression of Quantum Dephasing in Resonantly Driven Ensembles. Phys Rev Lett 2024; 132:043201. [PMID: 38335328 DOI: 10.1103/physrevlett.132.043201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Accepted: 01/02/2024] [Indexed: 02/12/2024]
Abstract
We have used quantum control to suppress the impact of random atom positions on coherent population transfer within atom pairs, enabling the observation of dipole-dipole driven Rabi oscillations in a Rydberg gas with hundreds of atoms. The method exploits the reduced coupling-strength sensitivity of the off-resonant Rabi frequency, and coherently amplifies the achievable population transfer in analogy to quasi-phase-matching in nonlinear optics. Simulations reproduce the experimental results and demonstrate the potential benefits of the technique to other many-body quantum control applications.
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Affiliation(s)
- C He
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
| | - R R Jones
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
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Jones RR, Ward MH, Deziel NC, Medgyesi DN, Pronk A, Nuckols JR, Fisher JA. Residential Proximity to Dioxin-emitting Facilities and Risk of Non-Hodgkin Lymphoma in the NIH-AARP Diet and Health Study. Cancer Epidemiol Biomarkers Prev 2021. [DOI: 10.1158/1055-9965.epi-21-0219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Abstract
Purpose: Few studies have investigated the relationship between risk of non-Hodgkin lymphoma (NHL) and residential proximity to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) emitted from industrial combustion and manufacturing sources. Methods: We evaluated this relationship among participants of the NIH-AARP Diet and Health Study, a prospective cohort (N = 548,845) in 6 states and 2 cities in the U.S. We linked geocoded enrollment addresses (1995–1996) with a U.S. Environmental Protection Agency database of 4,478 historical PCDD/F sources, which contained toxic equivalency quotient (TEQ) emissions estimates from 1995. Exposure metrics indicated presence/absence of any facility within 3 and 5km of participant homes, overall and by type of facility (e.g., coal-fired power plants, waste incinerators), which vary in emissions levels and constituency. We also calculated exposure as a distance- and toxicity-weighted average emissions index (AEI [g TEQ]). We used Cox regression to estimate associations (hazard ratios; HR and 95% confidence intervals; CI) with NHL and major subtypes, adjusting for and by strata of sociodemographic and lifestyle characteristics. Results: With 6,747 incident cases through 2011, we found no association between living near any or specific types of PCDD/F-emitting facilities and NHL risk. However, participants with an AEI >95th percentile within 5km had increased risk of NHL compared to unexposed (HR = 1.28; CI = 1.05–1.55; p-trend = 0.01). Specifically, we observed increased risk for lymphoplasmacytic lymphoma (HR = 2.98, CI = 1.16–7.63; p-trend = 0.03) and diffuse large B-cell lymphoma (HR = 1.65, CI = 1.11–2.46; p-trend = 0.01). Non-Hispanic blacks were nearly three times as likely as whites to live <5 km of a facility, although we had limited power to evaluate heterogeneity in associations by race/ethnicity. Associations did not vary by age, smoking status, body mass index, or urbanicity of residence. Conclusions: Using an exposure metric accounting for distance and the toxicity of emissions, we found significant positive associations between residential exposure to high PCDD/F emissions and risk of NHL and two subtypes. Our results underscore the hazard for populations living near sources of these persistent organic pollutants.
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Sándor P, Sissay A, Mauger F, Gordon MW, Gorman TT, Scarborough TD, Gaarde MB, Lopata K, Schafer KJ, Jones RR. Angle-dependent strong-field ionization of halomethanes. J Chem Phys 2019; 151:194308. [DOI: 10.1063/1.5121711] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Péter Sándor
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
| | - Adonay Sissay
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - François Mauger
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Mark W. Gordon
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
| | - T. T. Gorman
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - T. D. Scarborough
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Mette B. Gaarde
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - Kenneth Lopata
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - K. J. Schafer
- Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA
| | - R. R. Jones
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
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Terzian AS, Younes N, Greenberg AE, Opoku J, Hubbard J, Happ LP, Kumar P, Jones RR, Castel AD. Identifying Spatial Variation Along the HIV Care Continuum: The Role of Distance to Care on Retention and Viral Suppression. AIDS Behav 2018; 22:3009-3023. [PMID: 29603112 DOI: 10.1007/s10461-018-2103-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Distance to HIV care may be associated with retention in care (RIC) and viral suppression (VS). RIC (≥ 2 HIV visits or labs ≥ 90 days apart in 12 months), prescribed antiretroviral therapy (ART), VS (< 200 copies/mL at last visit) and distance to care were estimated among 3623 DC Cohort participants receiving HIV care in 13 outpatient clinics in Washington, DC in 2015. Logistic regression models and geospatial statistics were computed. RIC was 73%; 97% were on ART, among whom 77% had VS. ZIP code-level clusters of low RIC and high VS were found in Northwest DC, and low VS in Southeast DC. Those traveling ≥ 5 miles had 30% lower RIC (adjusted odds ratio (aOR) 0.71, 95% CI 0.58, 0.86) and lower VS (OR 0.70, 95% CI 0.52, 0.94). Geospatial clustering of RIC and VS was observed, and distance may be a barrier to optimal HIV care outcomes.
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Affiliation(s)
- A S Terzian
- Department of Epidemiology and Biostatistics, Milken Institute School of Public Health, The George Washington University, Washington, DC, 20052, USA.
| | - N Younes
- Department of Epidemiology and Biostatistics, Milken Institute School of Public Health, The George Washington University, Washington, DC, 20052, USA
| | - A E Greenberg
- Department of Epidemiology and Biostatistics, Milken Institute School of Public Health, The George Washington University, Washington, DC, 20052, USA
| | - J Opoku
- District of Columbia Department of Health, HIV/AIDS, Hepatitis, STD, and TB Administration, Washington, DC, USA
| | - J Hubbard
- Department of Epidemiology and Biostatistics, Milken Institute School of Public Health, The George Washington University, Washington, DC, 20052, USA
| | - L P Happ
- Department of Epidemiology and Biostatistics, Milken Institute School of Public Health, The George Washington University, Washington, DC, 20052, USA
| | - P Kumar
- School of Medicine, Georgetown University, Washington, DC, USA
| | - R R Jones
- Occupational and Environmental Epidemiology Branch, Division of Cancer Epidemiology & Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - A D Castel
- Department of Epidemiology and Biostatistics, Milken Institute School of Public Health, The George Washington University, Washington, DC, 20052, USA
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Abstract
We have employed intense, single-cycle THz pulses to explore strong-field ionization of low-lying Na Rydberg states in the low-frequency limit. At the largest fields used, F≃430 kV/cm, electrons with energies up to 60 eV are created. The field ionization threshold is greater than expected for adiabatic "over-the-barrier" ionization and is found to scale as n-3. In addition, for a given field amplitude, higher energy electrons are produced during the ionization of the most tightly bound states. These observations can be attributed to the suppression of scattering from the nonhydrogenic ion core, the long times required for Rydberg electrons to escape over the barrier in the field-dressed Coulomb potential, and the failure, in the single-cycle limit, of the standard prediction for electron energy transfer in an oscillating field. The latter, in particular, holds important implications for future strong-field experiments involving the interaction of ground-state atoms and molecules with true single-cycle laser fields.
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Affiliation(s)
- Sha Li
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
| | - R R Jones
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904, USA
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Egodapitiya KN, Li S, Jones RR. Terahertz-induced field-free orientation of rotationally excited molecules. Phys Rev Lett 2014; 112:103002. [PMID: 24679286 DOI: 10.1103/physrevlett.112.103002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Indexed: 06/03/2023]
Abstract
We have used picosecond THz pulses to induce transient field-free orientation of OCS molecules. Coherent optical Raman excitation prepares the molecules in rotational superposition states prior to THz irradiation, substantially enhancing the degree of orientation. The time-dependent alignment and orientation are characterized via Coulomb explosion in an intense probe laser. The degree of OCS orientation is an order of magnitude larger than previously observed following THz irradiation and is achieved with a significantly smaller THz field.The field-free orientation level is comparable to that generated using pulsed, two-color laser fields but is obtained with negligible target ionization.
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Affiliation(s)
- K N Egodapitiya
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
| | - Sha Li
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
| | - R R Jones
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
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Rule DC, Koch DW, Jones RR, Kercher CJ. Brassica
and Sugarbeet Forages for Lambs-Growth Performance of Lambs and Composition of Forage and Dock-Fat Fatty Acids. ACTA ACUST UNITED AC 2013. [DOI: 10.2134/jpa1991.0029] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- D. C. Rule
- Dep. of Animal Science; University of Wyoming, Box 3684, University Station; Laramie WY 82071
| | - D. W. Koch
- Dep. of Animal Science; University of Wyoming, Box 3684, University Station; Laramie WY 82071
| | - R. R. Jones
- Dep. of Animal Science; University of Wyoming, Box 3684, University Station; Laramie WY 82071
| | - C. J. Kercher
- Dep. of Animal Science; University of Wyoming, Box 3684, University Station; Laramie WY 82071
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Zhang X, Jones RR, Robicheaux F. Time-dependent electron interactions in double Rydberg wave packets. Phys Rev Lett 2013; 110:023002. [PMID: 23383901 DOI: 10.1103/physrevlett.110.023002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2012] [Indexed: 06/01/2023]
Abstract
We investigate the time-dependent evolution of a nonstationary three-body Coulomb system at energies just below the threshold for three-body breakup. Experimentally, short-pulse lasers excite two electrons in Ba to radially localized Rydberg wave packets with well-defined energy and angular momentum. Time-dependent interactions between the two electrons are probed using half-cycle electric field pulses. The measurements indicate that substantial energy exchange between the two electrons is nearly immediate upon the launch of the second wave packet. Fully quantum and classical calculations support this observation, predicting extremely rapid autoionization under the experimental conditions. The calculations also show very fast angular momentum exchange and sensitivity to the relative binding energies of the two electrons.
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Affiliation(s)
- X Zhang
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
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Abstract
We demonstrate a novel time-domain method to probe electronic coherence in ensembles of cold Rydberg atoms coupled via nearly resonant dipole-dipole interactions. Short laser pulses create coherent superpositions of few-electron eigenstates which evolve under the influence of pulsed electric fields. The pulses steer the dynamics, enhancing the probability for finding atoms in np, rather than initially excited ns states. The enhancement reflects the underlying electronic coherence which persists for >10 μs, 2 orders of magnitude longer than previously measured dephasing times in the same system. Simulations suggest that atom motion is responsible for the eventual decoherence.
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Affiliation(s)
- M R Kutteruf
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
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11
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Overstreet KR, Jones RR, Gallagher TF. Phase-dependent electron-ion recombination in a microwave field. Phys Rev Lett 2011; 106:033002. [PMID: 21405270 DOI: 10.1103/physrevlett.106.033002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Indexed: 05/30/2023]
Abstract
Using picosecond laser photoionization of Li in a microwave field we have observed phase-dependent reccombination of the photoelectrons with their parent Li+ ions. Recombination occurs at phases of the microwave field such that energy is removed from the photoelectron in the first microwave cycle after excitation, and there are two maxima in the recombination in each microwave cycle. These observations are consistent with observations made using an attosecond pulse train phase locked to an infrared pulse and with the "simpleman's" model, modified to account for the fact that the photoelectrons are produced in a Coulomb potential.
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Affiliation(s)
- K R Overstreet
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
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Betsch KJ, Pinkham DW, Jones RR. Directional emission of multiply charged ions during dissociative ionization in asymmetric two-color laser fields. Phys Rev Lett 2010; 105:223002. [PMID: 21231383 DOI: 10.1103/physrevlett.105.223002] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Indexed: 05/30/2023]
Abstract
Intense, asymmetric 1ω+2ω laser fields are used to affect the directional ejection of multiply charged ion fragments from a variety of molecules, including N2, O2, CO, HBr, and CO2. By tuning the relative phase, ϕ, between the two fields, we observe large forward-backward dissociation asymmetries. The largest asymmetries are obtained at the same values of ϕ for all species, suggesting a common dynamical mechanism. Following an independent phase calibration, the sign of the asymmetry appears to be opposite that expected from the standard enhanced ionization model.
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Affiliation(s)
- K J Betsch
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
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Abstract
Comparisons between visual and time-series inferences from behavioral data show that serial dependency in scores is likely to disrupt agreement between the two methods of analysis. If researchers follow an earlier recommendation that time-series analysis be used to supplement or confirm visual analysis, this study's findings suggest that the two methods will disagree most often when the data contain high levels of autocorrelation and when reliable behavorial changes are indicated by time-series analysis.
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Affiliation(s)
- R R Jones
- Evaluation Research Group and Suny, Binghamton
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Hartmann DP, Gottman JM, Jones RR, Gardner W, Kazdin AE, Vaught RS. Interrupted time-series analysis and its application to behavioral data. J Appl Behav Anal 2010; 13:543-59. [PMID: 16795632 PMCID: PMC1308162 DOI: 10.1901/jaba.1980.13-543] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
This paper uses a question-and-answer format to present the technical aspects of interrupted time-series analysis (ITSA). Topics include the potential relevance of ITSA to behavioral researchers, serial dependency, time-series models, tests of significance, and sources of ITSA information.
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Abstract
A time-series method is presented, nontechnically, for analysis of data generated in individual-subject operant studies, and is recommended as a supplement to visual analysis of behavior change in reversal or multiple-baseline experiments. The method can be used to identify three kinds of statistically significant behavior change: (a) changes in score levels from one experimental phase to another, (b) reliable upward or downward trends in scores, and (c) changes in trends between phases. The detection of, and reliance on, serial dependency (autocorrelation among temporally adjacent scores) in individual-subject behavioral scores is emphasized. Examples of published data from the operant literature are used to illustrate the time-series method.
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Shuman ES, Jones RR, Gallagher TF. Multiphoton assisted recombination. Phys Rev Lett 2008; 101:263001. [PMID: 19437638 DOI: 10.1103/physrevlett.101.263001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We have observed multiphoton assisted recombination in the presence of a 38.8 GHz microwave field. Stimulated emission of up to ten microwave photons results in energy transfer from continuum electrons, enabling recombination. The maximum electron energy loss is far greater than the 2Up predicted by the standard "simpleman's" model. The data are well reproduced by both an approximate analytic expression and numerical simulations in which the combined Coulomb and radiation fields are taken into account.
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Affiliation(s)
- E S Shuman
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
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Gabriel IH, Olavarria E, Jones RR, Whittaker S, Chaidos A, Apperley JF. Graft versus lymphoma effect after early relapse following reduced-intensity sibling allogeneic stem cell transplantation for relapsed cytotoxic variant of mycosis fungoides. Bone Marrow Transplant 2007; 40:401-3. [PMID: 17589536 DOI: 10.1038/sj.bmt.1705741] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Minns RS, Kutteruf MR, Zaidi H, Ko L, Jones RR. Preserving coherence in Rydberg quantum bits. Phys Rev Lett 2006; 97:040504. [PMID: 16907558 DOI: 10.1103/physrevlett.97.040504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2006] [Indexed: 05/11/2023]
Abstract
The effectiveness of decoherence suppression schemes is explored using quantum bits (qubits) stored in Li np Rydberg states. Following laser excitation, pulsed electric fields coherently control the electronic spin-orbit coupling, facilitating qubit creation, manipulation, and measurement. Spin-orbit coupling creates an approximate decoherence-free subspace for extending qubit storage times. However, sequences of fast NOT operations are found to be substantially more effective for preserving coherence.
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Affiliation(s)
- R S Minns
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
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Wells E, Ben-Itzhak I, Jones RR. Ionization of atoms by the spatial gradient of the pondermotive potential in a focused laser beam. Phys Rev Lett 2004; 93:023001. [PMID: 15323908 DOI: 10.1103/physrevlett.93.023001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2002] [Indexed: 05/24/2023]
Abstract
Ionization of atoms by the spatial gradient of the pondermotive potential in a focused laser beam is investigated. Rydberg ions, formed during the interaction of noble gas atoms with an intense laser pulse, are used to probe the gradient field. Rydberg ion species with higher ionization potentials are produced at locations where the gradient field is largest. The measured Rydberg ion yields differ dramatically from estimates that ignore gradient-field ionization, but are in good agreement with predictions that include the effect.
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Affiliation(s)
- E Wells
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
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Abstract
Coherent short-pulse laser excitation has been used to control the approximate energy and relative proximity of two valence electrons within the same alkaline-earth atom, thereby providing insight into the dynamical evolution of a three-body Coulomb system. Our time-domain experiments enable direct experimental study of the electron dynamics at the classical limit of a two-electron atom. As an example, we look at the mechanism of autoionization for one two-electron configuration class and find that the doubly excited atom decays through a single violent electron-electron collision rather than a gradual exchange of energy between the electrons.
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Affiliation(s)
- S N Pisharody
- Department of Physics, University of Virginia, 382 McCormick Road, Charlottesville, VA 22904-4714, USA
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Pisharody SN, Jones RR. Time-domain investigation of electron recapture via post-collision interaction in a double photoionization continuum. Phys Rev Lett 2003; 91:203002. [PMID: 14683359 DOI: 10.1103/physrevlett.91.203002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2003] [Indexed: 05/24/2023]
Abstract
Picosecond laser pulses have been used to sequentially photoionize both valence electrons from neutral Ba atoms, producing two radially localized continuum wave packets. The Coulomb interaction between the two outgoing electrons can result in the recapture of one of the electrons by the parent ion. The energy distribution of Rydberg ions formed via this "post-collision" interaction is measured as a function of the delay between the ionizing laser pulses. The experimental data are in agreement with the results of both a quantum sudden approximation and a classical simulation.
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Affiliation(s)
- S N Pisharody
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
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Zeibel JG, Jones RR. Centrifugal electron-ion recombination. Phys Rev Lett 2002; 89:093204. [PMID: 12190400 DOI: 10.1103/physrevlett.89.093204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2002] [Indexed: 05/23/2023]
Abstract
Transient electric-field pulses have been used to stimulate electron/ion recombination in a low density plasma in the presence of a static electric field. The measured recombination rates exhibit a strong dependence on the relative orientation of the pulsed and static fields. For weak pulses, the recombination rate is significantly higher for orthogonal as opposed to parallel or antiparallel field configurations. The enhanced recombination rate is attributed to the dynamic stabilization of high-m Rydberg levels that are populated during the pulse. Classical simulations confirm the importance of angular momentum rather than energy transfer.
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Affiliation(s)
- J G Zeibel
- Department of Physics, University of Virginia, Charlottesville, Virginia 22904-4714, USA
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DeWitt MJ, Wells E, Jones RR. Ratiometric comparison of intense field ionization of atoms and diatomic molecules. Phys Rev Lett 2001; 87:153001. [PMID: 11580695 DOI: 10.1103/physrevlett.87.153001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2001] [Indexed: 05/23/2023]
Abstract
Intense-laser ionization rates for rare gas atoms and diatomic molecules have been precisely compared by making simultaneous measurements of ionization yield vs laser intensity for mixed atomic and molecular targets. At a given laser intensity, the N (2) and F (2) ionization yields are slightly greater than that of Ar. Conversely, comparison of O (2) and S (2) with Xe indicates significant ionization suppression in these molecules. Recent molecular ionization models that successfully describe ionization suppression in O (2) and its absence in N (2) fail to explain our observations in F (2) and S (2).
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Affiliation(s)
- M J DeWitt
- Center for Atomic, Molecular, and Optical Science, Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904-4319, USA
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Abstract
We report 3 patients with granulomatous cutaneous T-cell lymphoma (CTCL) who showed necrobiosis histologically with palisading granulomas. Although granulomatous change may be present in up to 4% of cases of CTCL, necrobiosis is rare. Misdiagnosis may occur if epidermotropism is minimal or if atypical cells are masked by the granulomatous infiltrate. T-cell receptor gene analysis confirmed the presence of clonal T-cell populations in lesional skin from all 3 cases.
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Affiliation(s)
- A Woollons
- St John's Institute of Dermatology, St Thomas's Hospital, London, United Kingdom
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Abstract
This retrospective study documents the clinical features, electroencephalographic data, and outcome of 50 children with a history of seizures with fever that occurred after 5 years of age. Children with afebrile seizures before the onset of febrile seizures were excluded. Outcome was based on a cross-sectional survey and the follow-up period was 1-13 years. Of the 50 children, 40 had two or fewer febrile seizures after 5 years of age, and febrile seizures did not occur after 10 years of age. Twenty had complex febrile seizures, and 16 had a first-degree relative with febrile seizures. Five developed afebrile seizures, and 18 had educational difficulties. Epileptiform electroencephalographic abnormalities were observed in 22 but were not predictive of later afebrile seizures. Febrile seizures that occur after 5 years of age recur infrequently and cease by 10 years of age. The risk of developing afebrile seizures in this group is small.
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Affiliation(s)
- D W Webb
- Division of Paediatric Neurology, University of British Columbia and British Columbia Children's Hospital, Vancouver, Canada
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Kiang JG, Ding XZ, Gist ID, Jones RR, Tsokos GC. Corticotropin-releasing factor induces phosphorylation of phospholipase C-gamma at tyrosine residues via its receptor 2beta in human epidermoid A-431 cells. Eur J Pharmacol 1998; 363:203-10. [PMID: 9881591 DOI: 10.1016/s0014-2999(98)00792-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
This laboratory previously reported that corticotropin-releasing factor (CRF) increased intracellular free calcium concentrations, cellular cAMP, inositol 1,4,5-trisphosphate, protein kinase C activity, and protein phosphorylation in human A-431 cells. The increase was blocked by CRF receptor antagonist. In this study, we identified the type of CRF receptors present and investigated whether CRF induced tyrosine phosphorylation of phospholipase C-gamma via CRF receptors. Using novel primers in reverse transcriptase-polymerase chain reaction, we determined the CRF receptor type to be that of 2beta. The levels of the CRF receptor type 2beta were not altered in cells treated with activators of protein kinase C, Ca2+ ionophore, or cells overexpressing heat shock protein 70 kDa. Cells treated with CRF displayed increases in protein tyrosine phosphorylation approximately at 150 kDa as detected by immunoblotting using an antibody against phosphotyrosine. Immunoprecipitation with antibodies directed against phospholipase C-beta3, -gamma1, or -gamma2 isoforms (which have molecular weights around 150 kDa) followed by Western blotting using an anti-phosphotyrosine antibody showed that only phospholipase C-gamma1 and -gamma2 were phosphorylated. The increase in phospholipase C-gamma phosphorylation was concentration-dependent with an EC50 of 4.2+/-0.1 pM. The maximal phosphorylation by CRF at 1 nM occurred by 5 min. The CRF-induced phosphorylation was inhibited by the protein tyrosine kinase inhibitors genistein and herbimycin A, suggesting that CRF activates protein tyrosine kinases. Treatment of cells with CRF receptor antagonist, but not pertussis toxin, prior to treatment with CRF inhibited the CRF-induced phosphorylation, suggesting it is mediated by the CRF receptor type 2beta that is not coupled to pertussis toxin-sensitive G-proteins. Treatment with 1,2-bis(2iminophenoxy)ethane-N,N,N',N'-tetraacetic acid attenuated the phospholipase C-gamma phosphorylation. In summary, CRF induces phospholipase C-gamma phosphorylation at tyrosine residues, which depends on Ca2+ and is mediated by activation of protein tyrosine kinases via the CRF receptor type 2beta.
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Affiliation(s)
- J G Kiang
- Department of Clinical Physiology, Division of Medicine, Walter Reed Army Institute of Research, Washington, DC 20307-5100, USA.
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Abstract
AIMS The recent finding that human herpes virus 8 (HHV8) is found in the majority of Kaposi's sarcoma (KS) cases supports the epidemiological observation that the tumour may be caused by an infectious agent. This study aimed to address when and how HHV8 evolved. METHODS A cohort of African endemic KS (49 samples from 45 patients) and European KS (18 samples from 13 patients), spanning 27 years, was assessed for the presence of HHV8 by both standard solution phase polymerase chain reaction (PCR) and the newly described technique of TaqMan PCR. RESULTS HHV8 was present in approximately 49% (24 of 49 tissue samples) of the African cases and in more than 90% (16 of 18 tissue samples) of the European cohort, in keeping with recent seroepidemiological data. CONCLUSIONS HHV8 is strongly linked to the development of KS; however, in some patients, other factors may operate. The utility and flexibility of TaqMan PCR in detecting low copy viral target in human tissues was demonstrated.
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Affiliation(s)
- M M Kennedy
- Nuffield Department of Pathology & Bacteriology, University of Oxford, United Kingdom
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Jones RR, Fu P, Gallagher TF. Alteration of the lifetimes of autoionizing Rydberg states by a circularly polarized microwave field. J Chem Phys 1997. [DOI: 10.1063/1.473453] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Basarab T, Munn SE, Jones RR. Diagnostic accuracy and appropriateness of general practitioner referrals to a dermatology out-patient clinic. Br J Dermatol 1996; 135:70-3. [PMID: 8776362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A study was undertaken of new referrals by GPs to a dermatology clinic in a district general hospital over a 6-month period. Six hundred and eighty-six consecutive referrals to one consultant were analysed for diagnostic accuracy and requirement for referral. Only 47% of referral letters contained the correct diagnosis. Viral warts and psoriasis were best diagnosed (82 and 78%, respectively), but seborrhoeic warts and dermatofibromas caused difficulty (22 and 19%, respectively). Cutaneous malignancy was correctly diagnosed in 45% of referrals, and eczema, the commonest condition referred, in 54% of cases. Sixty-eight percent of referrals required hospital-based facilities for diagnosis (31%) or treatment/management (37%). Twenty-one per cent of patients referred attended for once-only visits, requiring no specialized diagnostic or therapeutic procedures. Such referrals should decrease with improved GP education. Eleven percent of referrals were for minor surgical procedures such as curettage, shave biopsy, or cryotherapy and would become unnecessary if such facilities were available in the community. Our data demonstrate the potential for management of up to one-third of current dermatological referrals within the community by improving education of GPs and providing appropriate facilities within the community. However, over two-thirds of patients required hospital facilities, a finding of considerable relevance to the future location of dermatological services.
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Affiliation(s)
- T Basarab
- Ealing Hospital NHS Trust, Southall, Middlesex, U.K
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Duncan DI, Jones RR. Interferometric characterization of Raman redistribution among perturbed Rydberg states of barium. Phys Rev A 1996; 53:4338-4342. [PMID: 9913407 DOI: 10.1103/physreva.53.4338] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Abstract
Four endothelial cell markers, two selective cytokeratin markers and a monoclonal smooth muscle antibody (SMA) were employed in the assessment of 19 cases of cutaneous angiosarcoma classified according to their degree of tumour differentiation. No labelling was seen for SMA or with cytokeratin markers MNF116 and CBL170. Expression of factor VIII-related antigen was seen in two tumours and positivity for CD34 (QBend 10 antibody) was found in four tumours. By contrast the pan-endothelial cell marker Ulex europeaus agglutinin 1 (UEA-1) and the CD31 marker JC70A labelled all cases of cutaneous angiosarcoma with the exception of one poorly differentiated tumour. These data confirm the endothelial cell origin of angiosarcoma, they demonstrate that CD31 and UEA1 are reliable markers in routinely processed tissue, and they suggest a lymphatic derivation for the tumour. This finding is in marked contrast to Kaposi's sarcoma where CD34 is the most reliable marker.
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Affiliation(s)
- G E Orchard
- Department of Dermatopathology, St John's Dermatology Centre, St Thomas' Hospital, London, UK
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Basarab T, Jones RR. Ofuji's disease with unusual histological features. Clin Exp Dermatol 1996; 21:67-71. [PMID: 8689777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
A 20-year-old lady presented with a 3-month history of an itchy eruption affecting her face and trunk. Erythematous annular plaques with follicular papules and pustules at the margins were present on her face consistent with Ofuji's disease. A perifollicular and perivascular eosinophil-rich infiltrate was seen histologically, with infiltration of the follicular epithelium by eosinophils and formation of eosinophilic microabscesses. An unusual feature was the presence of follicular mucinosis. Treatment with dapsone resulted in an improvement in the eruption after 2 weeks. Ofuji's eosinophilic pustular folliculitis is becoming increasingly frequently recognized, and may not be as rare as initial reports suggested. In 1965, Ise and Ofuji reported the case of a Japanese woman who had recurrent episodes of follicular pustules affecting her face and back accompanied by a peripheral eosinophilia. Following this, in 1970 Ofuji et al. reported three further cases and proposed the name eosinophilic pustular folliculitis. Although many of the early cases were in Japanese patients, reports of this disease affecting individuals from Europe and the United States have been increasing.
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Affiliation(s)
- T Basarab
- St John's Institute of Dermatology, St Thomas' Hospital, UK
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Tielking NE, Jones RR. Coherent population transfer among Rydberg states by subpicosecond, half-cycle pulses. Phys Rev A 1995; 52:1371-1381. [PMID: 9912375 DOI: 10.1103/physreva.52.1371] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Tielking NE, Bensky TJ, Jones RR. Effects of imperfect unipolarity on the ionization of Rydberg atoms by subpicosecond half-cycle pulses. Phys Rev A 1995; 51:3370-3373. [PMID: 9911982 DOI: 10.1103/physreva.51.3370] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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Jones RR, Tielking NE, You D, Raman C, Bucksbaum PH. Ionization of oriented Rydberg states by subpicosecond half-cycle electromagnetic pulses. Phys Rev A 1995; 51:R2687-R2690. [PMID: 9911996 DOI: 10.1103/physreva.51.r2687] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Jones RR. Environmental lead and children's intelligence. Obvious hypothesis is ignored. BMJ 1995; 310:397. [PMID: 7866223 PMCID: PMC2548771 DOI: 10.1136/bmj.310.6976.397] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Abstract
BACKGROUND Occupational allergy to mice is a major cause of disability among workers in mouse breeding and research facilities. Efforts to prevent and treat allergy require a detailed knowledge of exposure levels to allergen. OBJECTIVE This study was designed to quantitate the level of major mouse allergen (Mus m I) in central room air and immediate breathing zones under a variety of working conditions. METHODS An Andersen sampler (Groseby Andersen, Spirotech Div., Atlanta, Ga.) was used to collect allergen in each room. A Gillian Personal sampler (Gillian Instrument Corp., West Caldwell, N.J.) collected particles in the worker breathing zone. ELISA was used to quantitate the concentration of Mus m I collected on the two collection devices. RESULTS Total Mus m I recovered from Andersen samplers ranged from 0.2 to 1.5 ng/m3 in rooms without mice and 0.5 to 15.1 ng/m3 in rooms with mice. Allergen recovered from the zone of worker activity ranged from 1.2 to 2.7 ng/m3 in rooms without mice and from 16.6 to 563.0 ng/m3 in rooms with mice. Direct mouse contact was associated with the highest levels of exposure to Mus m I. Analysis revealed the bulk of allergen to be in mid-particle size ranges (3.3 to 10 microns) for mouse-containing rooms and in small particle size range (0.43 to 3.3 microns) for non-mouse-containing rooms, suggesting that small particles were carried along corridors from rooms with mice into non-mouse-containing rooms. Ventilation characteristics of rooms and mouse population density were evaluated with a "mouse loading" index (number of mice per cubic meter of ventilated air per hour). Mouse loading correlated strongly with small particles (< 3.3 microns) in ambient air. CONCLUSIONS Mus m I is widely distributed within mouse breeding facilities. Direct worker contact with mice seems to be the major factor in high level exposure.
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Affiliation(s)
- J L Ohman
- Allergy Department, New England Medical Center, Boston
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Abstract
Tufted haemangioma is a rare, acquired vascular tumour most commonly presenting in the first year of life. Some authors consider angioblastoma of Nakagawa and progressive capillary haemangioma to be the same condition, and include them in the lobular capillary haemangioma complex. There have been only a few case reports of tufted angioma in the literature, with little information on effective treatment. We describe a case of tufted angioma presenting in a 3-month-old girl. Because of the tumour's rapid growth, aggressive treatment was felt to be justified. There was no response to interferon alpha-2a but high-dose steroids were commenced with good results.
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Affiliation(s)
- S E Munn
- Department of Dermatology, Ealing Hospital, Middlesex, UK
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Burrows NP, Molina FA, Terenghi G, Clark PK, Haskard DO, Polak JM, Jones RR. Comparison of cell adhesion molecule expression in cutaneous leucocytoclastic and lymphocytic vasculitis. J Clin Pathol 1994; 47:939-44. [PMID: 7525658 PMCID: PMC502180 DOI: 10.1136/jcp.47.10.939] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
AIMS To compare the expression of the cell adhesion molecules intercellular adhesion molecule-1 (ICAM-1), ELAM-1 (E-selectin), and vascular cell adhesion molecule-1 (VCAM-1) in cutaneous leucocytoclastic and lymphocytic vasculitis. METHODS Immunohistochemical analysis was performed on early lesional skin biopsy specimens of leucocytoclastic vasculitis (n = 14), lymphocytic vasculitis (n = 10), non-lesional skin (n = 12), and normal skin (n = 5). A standard immunoperoxidase technique was used to detect expression of ICAM-1, E-selectin, VCAM-1, and the cell markers CD11a, CD11b, CD11c, von Willebrand factor, CD3, CD68, and neutrophil elastase (NP57). RESULTS Basal keratinocyte intercellular adhesion molecule-1 was expressed in eight (80%) cases of lymphocytic and in only one (7%) case of leucocytoclastic vasculitis, and not in non-lesional skin or control biopsy specimens from normal subjects. E-selectin was expressed on vascular endothelium in eight (57%) cases of leucocytoclastic and in seven (70%) cases of lymphocytic vasculitis. Endothelial vascular cell adhesion molecule-1 expression was seen in three (21%) biopsy specimens of leucocytoclastic and five (50%) of lymphocytic vasculitis. There were increased numbers of cells in the dermal infiltrate stained for NP57, CD11b, and CD11c in leucocytoclastic compared with lymphocytic vasculitis (p < 0.001, p = 0.013, p = 0.009, respectively); immunoreactive positive cells for CD3 and CD11a were increased in lymphocytic compared with leucocytoclastic vasculitis (p < 0.001, p = 0.011, respectively). CONCLUSIONS These observations indicate that upregulation of adhesion molecule expression occurs in both leucocytoclastic and lymphocytic vasculitis. The different patterns of adhesion molecule expression in the two groups of vasculitis may reflect differences in the local release of cytokines. In particular, detection of intercellular adhesion molecule-1 expression by keratinocytes in lymphocytic vasculitis is consistent with an active role for mediators derived from T lymphocytes in the pathogenesis of the lesion.
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Affiliation(s)
- N P Burrows
- Department of Histochemistry, Royal Postgraduate Medical School, Hammersmith Hospital, London
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Abstract
BACKGROUND T-cell receptor (TCR)-gamma gene rearrangements provide a specific clonal marker for T-cell malignancies of both the alpha beta and gamma delta varieties. A polymerase chain reaction (PCR)-based method was used in this study for investigation of clonal TCR-gamma gene rearrangements in a patient with a classical presentation of angioimmunoblastic lymphadenopathy with dysproteinemia (AILD) that subsequently progressed into an indolent form of dermal T-cell lymphoma. METHODS TCR gene rearrangements in patients with cutaneous T-cell lymphoma (CTCL) were examined using conventional Southern blot analysis and a newly developed PCR-based technique for clonal TCR gene rearrangements. The oligoprimers amplified rearranged V gamma and J gamma segments (including the N region) of the TCR-gamma gene, and PCR products were resolved using high resolution nondenaturing polyacrylamide gel electrophoresis. RESULTS The authors' results demonstrated good correlation between the two techniques in 10 patients with CTCL (9 patients with C beta and 1 patient with delta 2 rearrangements) and 10 control subjects. The PCR-based technique allowed the authors to detect the presence of an identical T-cell clone in all skin nodules, but not in the original lymph node affected by AILD. CONCLUSIONS This PCR-based method for detecting clonal TCR rearrangements is a highly sensitive and specific technique for detecting T-cell clones in fresh and paraffin embedded tissues. The presence of a T-cell clone in all skin nodules of this patient, but not in the original lymph node affected by AILD, confirms previous findings that in some cases of AILD, clonal T-cell expansion may not be detectable until a later stage of the disease.
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Affiliation(s)
- R C Yu
- Unit of Dermatology, Royal Postgraduate Medical School, London, U.K
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Burrows NP, Turnbull AJ, Punchard NA, Thompson RP, Jones RR. A trial of oral zinc supplementation in psoriasis. Cutis 1994; 54:117-8. [PMID: 7956335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A controlled double-blind study of oral zinc supplementation was performed in twenty-five patients with chronic plaque psoriasis over twelve weeks to assess changes in both psoriasis (using the psoriasis area and severity index) and neutrophil zinc content. There were no statistically significant differences in the psoriasis area and severity index during the trial between the placebo- and zinc-treated group, nor in the zinc levels. There was therefore no evidence of a benefit from zinc supplementation in patients with this disease.
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Affiliation(s)
- N P Burrows
- St. John's Institute of Dermatology, United Medical and Dental School, St. Thomas' Hospital, London, United Kingdom
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