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Featured researches published by A.I. van Sighem.


The Lancet | 2008

Life expectancy of individuals on combination antiretroviral therapy in high-income countries: a collaborative analysis of 14 cohort studies

Robert S. Hogg; Lima; Jac Sterne; Sophie Grabar; Manuel Battegay; M. Bonarek; Antonella d'Arminio Monforte; Anna Esteve; Michael Gill; Ross Harris; Amy C. Justice; A. Hayden; Fiona Lampe; Amanda Mocroft; Michael J. Mugavero; Schlomo Staszewski; Jan Christian Wasmuth; A.I. van Sighem; Mari M. Kitahata; Jodie L. Guest; Matthias Egger; Margaret T May; Antiretroviral Therapy Cohort Coll

BACKGROUND Combination antiretroviral therapy has led to significant increases in survival and quality of life, but at a population-level the effect on life expectancy is not well understood. Our objective was to compare changes in mortality and life expectancy among HIV-positive individuals on combination antiretroviral therapy. METHODS The Antiretroviral Therapy Cohort Collaboration is a multinational collaboration of HIV cohort studies in Europe and North America. Patients were included in this analysis if they were aged 16 years or over and antiretroviral-naive when initiating combination therapy. We constructed abridged life tables to estimate life expectancies for individuals on combination antiretroviral therapy in 1996-99, 2000-02, and 2003-05, and stratified by sex, baseline CD4 cell count, and history of injecting drug use. The average number of years remaining to be lived by those treated with combination antiretroviral therapy at 20 and 35 years of age was estimated. Potential years of life lost from 20 to 64 years of age and crude mortality rates were also calculated. FINDINGS 18 587, 13 914, and 10 854 eligible patients initiated combination antiretroviral therapy in 1996-99, 2000-02, and 2003-05, respectively. 2056 (4.7%) deaths were observed during the study period, with crude mortality rates decreasing from 16.3 deaths per 1000 person-years in 1996-99 to 10.0 deaths per 1000 person-years in 2003-05. Potential years of life lost per 1000 person-years also decreased over the same time, from 366 to 189 years. Life expectancy at age 20 years increased from 36.1 (SE 0.6) years to 49.4 (0.5) years. Women had higher life expectancies than did men. Patients with presumed transmission via injecting drug use had lower life expectancies than did those from other transmission groups (32.6 [1.1] years vs 44.7 [0.3] years in 2003-05). Life expectancy was lower in patients with lower baseline CD4 cell counts than in those with higher baseline counts (32.4 [1.1] years for CD4 cell counts below 100 cells per muL vs 50.4 [0.4] years for counts of 200 cells per muL or more). INTERPRETATION Life expectancy in HIV-infected patients treated with combination antiretroviral therapy increased between 1996 and 2005, although there is considerable variability between subgroups of patients. The average number of years remaining to be lived at age 20 years was about two-thirds of that in the general population in these countries.


Physics Letters B | 2000

Measurement of the proton structure function F-2 at very low Q(2) at HERA

J. Breitweg; C.H. Bokel; M. Botje; N.C. Brummer; Jos J. Engelen; S.J.L.A. Grijpink; E.N. Koffeman; P. Kooijman; S.E.S. Schagen; A.I. van Sighem; H.G.J.M. Tiecke; Niels Tuning; J.J. Velthuis; J.H. Vossebeld; L. Wiggers; E. de Wolf

A measurement of the proton structure function F_2(x,Q^2) is presented in the kinematic range 0.045 GeV^2<Q^2<0.65 GeV^2 and 6*10^{-7}<x<1*10^{-3}. The results were obtained using a data sample corresponding to an integrated luminosity of 3.9pb^-1 in e^+p reactions recorded with the ZEUS detector at HERA. Information from a silicon-strip tracking detector, installed in front of the small electromagnetic calorimeter used to measure the energy of the final-state positron at small scattering angles, together with an enhanced simulation of the hadronic final state, has permitted the extension of the kinematic range beyond that of previous measurements. The uncertainties in F_2 are typically less than 4%. At the low Q^2 values of the present measurement, the rise of F_2 at low x is slower than observed in HERA data at higher Q^2 and can be described by Regge theory with a constant logarithmic slope. The dependence of F_2 on Q^2 is stronger than at higher Q^2 values, approaching, at the lowest Q^2 values of this measurement, a region where F_2 becomes nearly proportional to Q^2.A measurement of the proton structure function F-2(x, Q(2)) is presented in the kinematic range 0.045 GeV2 lt Q(2) lt 0.65 GeV2 and 6 . 10(-7) lt x lt 1 . 10(-3). The results were obtained using a data sample corresponding to an integrated luminosity of 3.9 pb(-1) in e(+)p reactions recorded with the ZEUS detector at HERA. Information from a silicon-strip tracking detector, installed in front of the small electromagnetic calorimeter used to measure the energy of the final-state positron at small scattering angles, together with an enhanced simulation of the hadronic final state, has permitted the extension of the kinematic range beyond that of previous measurements. The uncertainties in F-2 are typically less than 4%. At the low Q(2) values of the present measurement, the rise of F-2 at low x is slower than observed in HERA data at higher Q(2) and can be described by Regge theory with a constant logarithmic slope partial derivative lnF(2)/partial derivative ln(1/x). The dependence of F-2 on Q(2) is stronger than at higher Q(2) values, approaching, at the lowest Q(2) values of this measurement, a region where F-2 becomes nearly proportional to Q(2).


European Physical Journal C | 2000

Measurement of D*(+/-) production and the charm contribution to F-2 in deep inelastic scattering at HERA

J. Breitweg; C.H. Bokel; M. Botje; N.C. Brummer; Jos J. Engelen; E.N. Koffeman; P. Kooijman; A.I. van Sighem; H.G.J.M. Tiecke; Niels Tuning; W. Verkerke; J.H. Vossebeld; L. Wiggers; E. de Wolf

Abstract. The production of


European Physical Journal C | 1999

Exclusive electroproduction of \(\rho^0\) and \(J/\psi\) mesons at HERA

J. Breitweg; C.H. Bokel; M. Botje; N.C. Brummer; J.J. Engelen; E.N. Koffeman; P. Kooijman; A.I. van Sighem; H. Tiecke; Niels Tuning; W. Verkerke; J.H. Vossebeld; L. Wiggers; E. de Wolf

D^{\ast \pm}


European Physical Journal C | 1998

Elastic and proton-dissociative \(\rho^0\) photoproduction at HERA

J. Breitweg; C.H. Bokel; M. Botje; N.C. Brummer; F. Chlebana; J.J. Engelen; E.N. Koffeman; P. Kooijman; A.I. van Sighem; H. Tiecke; Niels Tuning; W. Verkerke; J.H. Vossebeld; M. Vreeswijk; L. Wiggers; E. de Wolf

(2010) mesons in deep inelastic scattering has been measured in the ZEUS detector at HERA using an integrated luminosity of 37 pb


Physics Letters B | 1996

Measurement of elastic

M. Derrick; M.A.J. Botje; F.S. Chlebana; J.J. Engelen; M. de Kamps; P. Kooijman; A. Kruse; A.I. van Sighem; H.G.J.M. Tiecke; W. Verkerke; J.H. Vossebeld; M. Vreeswijk; L.W. Wiggers; E. de Wolf; R. van Woudenberg

^{-1}


European Physical Journal C | 1996

\phi

M. Derrick; M. Botje; F.S. Chlebana; J.J. Engelen; M. de Kamps; P. Kooijman; A. Kruse; A.I. van Sighem; H. Tiecke; W. Verkerke; J.H. Vossebeld; M. Vreeswijk; L. Wiggers; E. de Wolf; R. van Woudenberg

. The decay channels


Physics Letters B | 1997

photoproduction at HERA

J. Breitweg; C.H. Bokel; M.A.J. Botje; N.C. Brummer; F.S. Chlebana; J.J. Engelen; M. de Kamps; P. Kooijman; A. Kruse; A.I. van Sighem; H.G.J.M. Tiecke; W. Verkerke; J.H. Vossebeld; M. Vreeswijk; L.W. Wiggers; E. de Wolf

D^{\ast +}\rightarrow D^0 \pi^+


European Physical Journal C | 2001

Measurement of the F-2 structure function in deep inelastic e(+)p scattering using 1994 data from the ZEUS detector at HERA

J. Breitweg; C.H. Bokel; M. Botje; N.C. Brummer; Jos J. Engelen; S.J.L.A. Grijpink; E.N. Koffeman; P. Kooijman; S.E.S. Schagen; A.I. van Sighem; H.G.J.M. Tiecke; E. Tassi; Niels Tuning; J.J. Velthuis; J.H. Vossebeld; L. Wiggers; E. de Wolf

(+ c.c.), with


Physics Letters B | 1997

D* Production in deep inelastic scattering at HERA

J. Breitweg; C.H. Bokel; M.A.J. Botje; F.S. Chlebana; J.J. Engelen; P. Kooijman; A.I. van Sighem; H.G.J.M. Tiecke; Niels Tuning; W. Verkerke; Joost Vossebeld; M. Vreeswijk; L.W. Wiggers; E. de Wolf

D^0 \rightarrow K^- \pi^+

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E. de Wolf

University of Amsterdam

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C.H. Bokel

University of Amsterdam

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J. Breitweg

United States Department of Energy

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L. Wiggers

University of Amsterdam

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M. Botje

University of Amsterdam

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Niels Tuning

University of Amsterdam

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J.J. Engelen

University of Amsterdam

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W. Verkerke

University of Amsterdam

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