Dissociative photoionization of NO across a shape resonance in the XUV range using circularly polarized synchrotron radiation.

We report benchmark results for dissociative photoionization (DPI) spectroscopy and dynamics of the NO molecule in the region of the σ* shape resonance in the ionization leading to the NO+(c3Π) ionic state. The experimental study combines well characterized extreme ultraviolet (XUV) circularly polarized synchrotron radiation, delivered at the DESIRS beamline (SOLEIL), with ion-electron coincidence 3D momentum spectroscopy. The measured (N+, e) kinetic energy correlation diagrams reported at four discrete photon energies in the extended 23-33 eV energy range allow for resolving the different active DPI reactions and underline the importance of spectrally resolved studies using synchrotron radiation in the context of time-resolved studies where photoionization is induced by broadband XUV attosecond pulses. In the dominant DPI reaction which leads to the NO+(c3Π) ionic state, photoionization dynamics across the σ* shape resonance are probed by molecular frame photoelectron angular distributions where the parallel and perpendicular transitions are highlighted, as well as the circular dichroism CDAD(θe) in the molecular frame. The latter also constitute benchmark references for molecular polarimetry. The measured dynamical parameters are well described by multichannel Schwinger configuration interaction calculations. Similar results are obtained for the DPI spectroscopy of highly excited NO+ electronic states populated in the explored XUV photon energy range.

The role of Rydberg states in photoionization of NO2 and (NO+, O-) ion pair formation induced by one VUV photon.

We report a combined experimental and theoretical study of photoionization (PI) of the NO2 molecule into the NO2(+) (X (1)Σg(+)) ground state and the photodissociation of NO2 into the NO(+)((1)Σ(+)) + O(-)((2)P) ion pair. These processes were induced by 10.9 eV-13 eV synchrotron radiation and the products were detected using electron-ion or O(-)-NO(+) coincident momentum spectroscopy. The results demonstrate the strong influence of [R(∗)(4b2)(-1), nlα(i), v2(')] Rydberg states vibrationally resolved in the v2(') bending modes for both processes. In particular, we emphasize two regions around 11.5 eV and 12.5 eV that were studied in more detail for their relevance to 400 nm multiphoton ionization induced by femtosecond pulses. The photoelectron energy spectra and asymmetry parameters support the existence of two PI mechanisms, as probed with the help of fixed-nuclei frozen-core Hartree-Fock calculations. We found significant deviations from Franck-Condon ionization predictions which may be assigned to vibronic coupling of NO2(∗) states such as that induced by a conical intersection. The limited agreement between theory and experiment, even for the non-resonant processes, indicates the need for calculations that go beyond the approximations used in the current study. Ion pair formation leads to strong vibrational and rotational excitation of the NO(+)((1)Σ(+),v) product, with an ion fragment angular anisotropy depending on both the v2(') bending quantum number of the excited parent molecule and the v vibrational level of the fragment.

Valence and inner-valence shell dissociative photoionization of CO in the 26-33 eV range. II. Molecular-frame and recoil-frame photoelectron angular distributions.

Experimental and theoretical results for molecular-frame photoemission are presented for inner-valence shell photoionization of the CO molecule induced by linearly and circularly polarized light. The experimental recoil frame photoelectron angular distributions (RFPADs) obtained from dissociative photoionization measurements where the velocities of the ionic fragment and photoelectron were detected in coincidence, are compared to RFPADs computed using the multichannel Schwinger configuration interaction method. The formalism for including a finite lifetime of the predissociative ion state is presented for the case of general elliptically polarized light, to obtain the RFPAD rather than the molecular frame photoelectron angular distribution (MFPAD), which would be obtained with the assumption of instantaneous dissociation. We have considered photoionization of CO for the photon energies of 26.0 eV, 29.5 eV, and 32.5 eV. A comparison of experimental and theoretical RFPADs allows us to identify the ionic states detected in the experimental studies. In addition to previously identified states, we found evidence for the 2 (2)Δ state with an ionization potential of 25.3 eV and (2)Σ(+) states with ionization potentials near 32.5 eV. A comparison of the experimental and theoretical RFPADs permits us to estimate predissociative lifetimes of 0.25-1 ps for some of the ion states. Consideration of the MFPADs of a series of (2)Π ion states indicates the importance of inter-channel coupling at low photoelectron kinetic energy and the limitations of a single-channel analysis based on the corresponding Dyson orbitals.

Influence of shape resonances on the angular dependence of molecular photoionization delays.

Characterizing time delays in molecular photoionization as a function of the ejected electron emission direction relative to the orientation of the molecule and the light polarization axis provides unprecedented insights into the attosecond dynamics induced by extreme ultraviolet or X-ray one-photon absorption, including the role of electronic correlation and continuum resonant states. Here, we report completely resolved experimental and computational angular dependence of single-photon ionization delays in NO molecules across a shape resonance, relying on synchrotron radiation and time-independent ab initio calculations. The angle-dependent time delay variations of few hundreds of attoseconds, resulting from the interference of the resonant and non-resonant contributions to the dynamics of the ejected electron, are well described using a multichannel Fano model where the time delay of the resonant component is angle-independent. Comparing these results with the same resonance computed in e-NO+ scattering highlights the connection of photoionization delays with Wigner scattering time delays.

Valence and inner-valence shell dissociative photoionization of CO in the 26-33 eV range. I. Ion-electron kinetic energy correlation and laboratory frame photoemission.

The (V(A+), V(e), ê) vector correlation method, combining imaging and time-of-flight resolved electron-ion coincidence techniques, is used to probe dissociative photoionization (DPI) of CO induced by vacuum ultra violet linearly or circularly polarized synchrotron radiation in the 26-33 eV photon excitation energy range. It provides original information about both the photoionization dynamics of the CO molecule and the dissociation dynamics of the CO(+) molecular ions. The explored region corresponds to valence and inner-valence CO(+) ionic states, which involve doubly or multiply excited electronic configurations. In this paper I we identify up to 17 DPI reaction pathways by the position of the intermediate CO(+) molecular states in the Franck-Condon region and the (C(+) + O) or (O(+) + C) dissociation limits to which they correlate. For these processes we report the laboratory frame beta(C+/O+) and beta(e) asymmetry parameters as well as the relative branching ratios in selected binding energy bands. The I(chi,theta(e),phi(e)) molecular frame photoelectron angular distributions for selected PI processes will be reported in a companion paper II and compared with multichannel Schwinger configuration interaction ab initio calculations of these observables.

Outcome of children after maternal primary Toxoplasma infection during pregnancy with emphasis on avidity of specific IgG. The Study Group.

Congenital toxoplasmosis results from maternal primary infection during pregnancy. In our serologic screening study 42 of 16,733 pregnant women had findings suggestive of primary infection. Here we document the outcome of their offspring, 37 of 39 liveborn children. After 12 months postnatally, serologically verified congenital toxoplasmosis appeared in 4 children. All these children had persisting IgG at the age of 12 months by both the dye test and the IgG enzyme-linked immunosorbent assay. All the congenitally infected infants had also specific IgM and IgA and showed significant increases in avidity of specific IgG during the 12-month follow-up. One of them had a unilateral retinal scar and intracranial calcifications. An additional 3 infants of the mothers with primary infection during early pregnancy presented with unilateral retinal scars but without seroresponses during the first 12 months of life. Maternal high avidity of IgG during the first trimester is a strong indicator against primary infection during pregnancy; the fetuses of such mothers are at low risk for congenital toxoplasmosis.

Models for prediction of the frequency of toxoplasmosis in pregnancy in situations of changing infection rates.

BACKGROUND: Estimation of the number of women infected during pregnancy with Toxoplasma gondii from seroconversion or seroprevalence data meets with various difficulties. Because of the high risk of transmission of the infection to the fetus such infections are however a major concern in pregnancy-related health planning. METHODS: The expected annual percentage of pregnant women infected with Toxoplasma was calculated using models with varying assumptions with regard to the infection rate, assumed to be independent of age but dependent on calendar time. Three situations were studied: a stable situation, a sudden fall in the infection rate and a gradually declining (slower or faster) infection rate over the lifetime of the pregnant women. RESULTS: With a constant infection rate, a maximum number of affected pregnancies occurs at a yearly infection rate of 4%. In countries with a strongly decreasing annual infection rate, estimates based on data on the relation between age and seropositivity related to only one period of time tend to overestimate the number of affected pregnancies by as much as 60%. CONCLUSIONS: In countries in transition from high to low infection rates, it is likely that the influence of decreasing immunity will, at least temporarily, more than outweigh the influence of the falling infection rates, resulting in a higher number of infected pregnant women. The models used can also describe situations with age-dependent variation in the infection rate, and may well apply to other infectious diseases relevant to pregnancy.

Upper gastrointestinal symptoms in the third trimester of the normal pregnancy.

OBJECTIVES: To report on the prevalence of well-being, heartburn, nausea, and vomiting related to gestational week, parity, and age in the third trimester of the normal pregnancy. STUDY DESIGN: Self-administered questionnaire filled in daily by 180 women from 31st gestational week to delivery. RESULTS: The study was completed by 120 women. The weekly prevalence of well-being decreased from 50% at the 31st gestational week to 24% at the 42nd gestational week (P = 0.00001). The weekly prevalence of heart-burn (approximately 60%), nausea (approximately 16%) and vomiting (approximately 7%) was nearly constant throughout the study period. Well-being was inversely related to parity, (P = 0.006), heartburn positively related to age (P = 0.016), and nausea and vomiting inversely related to age (P = 0.003 and P = 0.044). CONCLUSION: Discomforts are customary in the third trimester of normal pregnancy. However, heartburn and especially nausea and vomiting appeared occasionally and were not present for longer periods. The findings that heartburn, nausea and vomiting had different relations to age may suggest different etiologies.

Experimental infection with Toxoplasma gondii in farmed mink (Mustela vison S.).

Live Toxoplasma gondii tissue cysts (Strain 119) were administered orally to five mink (Mustela vison S.) and five mink were inoculated with a suspension of ultrasonicated Toxoplasma gondii trophozoites (RH-strain). Seroconversion was observed in all animals administered live T. gondii cysts indicating that infection was established. Likewise seroconversion was observed in three out of four animals administered ultrasonicated T. gondii trophozoites. Faecal shedding of oocysts of T. gondii was not demonstrated in any of the infected animals. Histologically chronic meningitis with calcification was seen in all animals. Cerebral T. gondii tissue cysts were detected in four animals administered live tissue cysts. The study demonstrates that mink can be experimentally infected with T. gondii, thus representing a potential infection source for man, when considering the pelting procedure.

[Congential toxoplasmosis and ocular involvement. A review with 6 case reports]. / Medfødt toksoplasmose og øjenaffektion. En oversigt med seks sygehistorier.

A review is presented of the ocular affections in congenital toxoplasmosis. The epidemiological, pathogenetic and pathological conditions are reviewed together with the clinical manifestations and the diagnostic and therapeutic possibilities. On the basis of incidence investigations and knowledge from the literature, it must be assumed that approximately 190 infants with congenital toxoplasmosis are born annually in Denmark. Only approximately 15% of the infections will be symptom-producing and will be diagnosed neonatally, but more than 85% of the children with congenital toxoplasmosis will develop chorioretinitis on delivery or later in life and this will frequently cause reduction in vision or blindness. Congenital toxoplasmosis must be regarded as the commonest cause of chorioretinitis and it is probable that congenital toxoplasmosis and chorioretinitis due to toxoplasmosis are considerably underdiagnosed in Denmark. Treatment of congenital toxoplasmosis from birth improve the prognosis. Toxoplasmosis should be suspected in all cases of chorioretinitis. When antibodies to Toxoplasma gondii are demonstrated and the clinical picture is compatible with toxoplasmosis and when there is no other diagnosis, anti-Toxoplasma treatment should be considered. It is important to inform pregnant women about prophylactic measures. If investigations for toxoplasmosis were introduced in the prenatal or perinatal examinations, treatment could be initiated from birth and the diagnosis could be confirmed by possible activation of the chorioretinitis at a later date. Six case reports are presented.

[Laparoscopic sterilization in women using Filshie clips]. / Laparoskopisk sterilisation af kvinder med Filshie-klips.

A material of 194 women sterilized laparoscopically using Filshie clips was followed for 16-51 months. The method is economical (short stay in hospital) and with little damage to the tube. Only few complaints and no complications were recorded. One woman became pregnant in the observation period, a failure rate of 0.5%. According to the literature the potential for reversal seems very good. The method seems to have some advantages over other methods in common use for female sterilization.

PIP: The increasing number of sterilizations among young women with few or no children had increased interest in the development of methods which are simple, effective, cosmetically suitable and which involve the fewest possible sick days and which minimize destruction of the Fallopian tube so that refertilization has the best chance for success. In Denmark the method used most often in laparoscopy with electrocoagulation. Since 1983 the Fredericksberg hospital has exclusively used laparoscopic sterilization with the Filshie clip. A total of 194 women were sterilized during the period Aug. 1983-Aug. 1986. The mark V Filshie clip was applied a few cm from the horn of the uterus with an applicator which was introduced intraperitoneally with a special trocar. The majority of the women were in their 30s with 20% in their 20s and 24% in their 40s. The patients were observed for 16-51 months. There were no operative complications. 2 patients complained of abdominal pain postoperatively and were treated with antibiotics for suspected perimetritis. 1 patient complained of dysuria and pain but recovered spontaneously within 4 weeks. 1 woman became pregnant 11 months after the operation, corresponding to a pregnancy frequency of .5%. Upon resterilization it was found that the left clip had slipped off. None of the patients were refertilized. 13% of the women had had no children; 27%, 1 child; 44%, 2; 13%, 3; and 2%, 4 or more. 52% of the woman had no induced abortions; 26%, 1; 15%, 2; 4%, 3 and 3%, 4 or more.

[Headache, fatigue and edema of the lower limbs during the third trimester of normal pregnancy]. / Hovedpine, traethed og underekstremitetsødem i tredje trimester af den normale graviditet.

A series of 180 pregnant women with normal pregnancies participated in the study. A questionnaire concerning the presence of headache, fatigue and oedema of the lower limbs was filled out daily from the 30th gestational week to delivery. After the study period 120 questionnaires, of whom eight were excluded, were available for analysis. The weekly prevalences of headache and fatigue during the observation-period were nearly constant with values of 20% and 50%, respectively. The weekly prevalence of oedema increased significantly from 20% in the 31st week to 60% in the 42nd gestational week. Thirty-five percent had not suffered from headache, 22% did not report fatigue, and 42% did not describe oedema at all during the third trimester. The prevalence of headache and fatigue correlated significantly to increasing parity whereas headache was significantly correlated to decreasing age. Headache, fatigue, and oedema are common symptoms in the third trimester of normal pregnancy, and as such their presence alone should not usually give cause for suspicion of disease.

[Lactic acidosis associated with metformin]. / Metforminassocieret laktatacidose.

Lactic acidosis is an extremely rare but serious complication of treatment with metformin. In order to avoid lactate acidosis, it is important to select patients correctly and to ensure that contraindications such as cases of renal involvement, advanced age and chronic alcoholism are observed prior to treatment with metformin. In addition, it is necessary to carry out meticulous follow-up control of the patients with annual investigations of renal and hepatic functions and clinical assessment approximately four times per annum with the object of revealing commencing symptoms of diabetes and ischaemic conditions. In this manner, the majority of cases of lactate acidosis can be avoided.

[Occurrence of toxoplasmosis in pregnant women in Denmark. A study of 5.402 pregnant women]. / Forekomsten af toksoplasmose hos gravide i Danmark. En undersøgelse af 5.402 gravide.

Consecutive serum samples from 5402 women were analyzed for specific IgG and IgM Toxoplasma gondii antibodies by enzyme immunosorbent assay. The prevalence of IgG antibodies was 27.4%. The seroconversion rate was estimated to be 1.16% per year (SE = 0.0017) in all age groups, consistent with an incidence of acute toxoplasmosis in pregnant women of 0.65%. Based on theses figures, the estimated number of congenitally infected cases are discussed. There was no difference in the prevalence of antibodies in women from rural or urban areas, or from different parts of Denmark.

[Toxoplasmosis-chorioretinitis: clinical course and treatment of seven patients]. / Toksoplasmose-chorioretinitis: klinisk forløb og behandling af syv patienter.

Toxoplasmosis is a major and preventable cause of severe visual loss and blindness in young people. Ocular toxoplasmosis is the leading cause of posterior uveitis and in most cases it represents a late manifestation of a congenital infection. The clinical picture and anti-Toxoplasma therapy of seven patients referred to the Department of Infectious Diseases, Hvidovre Hospital is described. All patients had clinical ocular toxoplasmosis at initial examination with unilateral focal necrotizing retinitis associated with typical old, pigmented scars. All patients had anti-toxoplasmosis IgG antibodies. After anti-Toxoplasma therapy with sulfadiazine, pyrimethamine and corticosteroid the ocular lesions were healed to atrophic scars and the inflammatory activity disappeared. We conclude that when the clinical picture is compatible with toxoplasmosis, antibodies to Toxoplasma gondii are demonstrated and there is no other diagnosis, anti-Toxoplasma treatment should be considered. It is important to inform pregnant women about prophylactic measures, and to perform a serological screening of newborns, since treatment of congenital toxoplasmosis from birth improves the prognosis.

[Parasitic diseases in patients with impaired immune response. Clinical picture and diagnosis]. / Parasitaere sygdomme hos patienter med nedsat immunforsvar. Klinisk billede og diagnose.

Patients with impaired immune system are frequently infected with various parasitic diseases. The clinical picture is characterized by unusual manifestations and frequently severe recurrences of infections which are not normally serious. Some almost parasitic microorganisms produce symptoms exclusively in patients with impaired immune system. Parasitic infections have become increasingly common with the increasing number of patients who live for prolonged periods with impaired immune systems, often as a result of infection with HIV. Among the numerous parasitic infections which are observed in man, there are a few which occur particularly frequently in patients with impaired immune systems. This is a brief review of the clinical pictures and diagnostic options in parasitic disease in individuals with impaired immune system with particular emphasis on infections caused by: Pneumocystis carinii, Toxoplasma gondii, Cryptosporidium ssp., Microspora, Entamoeba histolytica, Leishmania ssp., and Strongyloides stercoralis. In patients with impaired immunity, parasitic infections frequently cause nonspecific symptoms and, on account of the impaired immunity, antibodies to the parasite are not always produced. The diagnosis of these infections is, therefore, based on morphological demonstration of the microorganism concerned, culture, specific antigen or DNA defections.

The course of inflammatory bowel disease during pregnancy and postpartum: a prospective European ECCO-EpiCom Study of 209 pregnant women.

BACKGROUND: The impact of pregnancy on the course of IBD is still controversial. AIM: To investigate the impact of pregnancy on IBD and to search for factors with potential impact on remission. METHODS: Pregnant IBD women from 12 European countries were enrolled between January 2003 and December 2006 and compared at conception (1:1) with nonpregnant IBD women. Data on disease course were prospectively collected at each trimester during pregnancy and in the postpartum (6 months) using a standardised questionnaire. RESULTS: A total of 209 pregnant IBD women were included: 92 with Crohn's disease (CD; median age 31 years, range 17-40) and 117 with ulcerative colitis (UC; median age 32 years, range 19-42). No statistically significant difference in disease course during pregnancy and postpartum was observed between pregnant and nonpregnant CD women. Longer disease duration in CD and immunosuppressive therapy were found to be risk factors for activity during pregnancy. Pregnant UC women were more likely than nonpregnant UC women to relapse both during pregnancy (RR 2.19; 95% CI: 1.25-3.97, 0.004) and postpartum (RR 6.22; 95% CI: 2.05-79.3, P = 0.0004). During pregnancy, relapse was mainly observed in the first (RR 8.80; 95% CI 2.05-79.3, P < 0.0004) and the second trimester (RR 2.84, 95% CI 1.2-7.45, P = 0.0098). CONCLUSIONS: Pregnant women with Crohn's disease had a similar disease course both during pregnancy and after delivery as the nonpregnant women. In contrast, pregnant women with ulcerative colitis were at higher risk of relapse during pregnancy and in the postpartum than nonpregnant ulcerative colitis women.

Molecular frame and recoil frame photoelectron angular distributions from dissociative photoionization of NO2.

The authors report measured and computed molecular frame photoelectron angular distributions (MFPADs) and recoil frame photoelectron angular distributions (RFPADs) for the single photon ionization of the nonlinear molecule NO2 leading to the (1a2)-1 b 3A2 and (4a1)-1 3A1 states of NO2+. Experimentally, the RFPADs were obtained using the vector correlation approach applied to the dissociative photoionization (DPI) involving these molecular ionic states. The polar and azimuthal angle dependences of the photoelectron angular distributions are measured relative to the reference frame provided by the ion recoil axis and direction of polarization of the linearly polarized light. Experimental results are reported for the photon excitation energies hnu=14.4 and 22.0 eV. Theoretically the authors give expressions for both the MFPAD and the RFPAD. They show that the functional form in the recoil frame, where an average over the azimuthal dependence of the molecular fragments about the recoil direction is made, is identical to that they have earlier found for the DPI experiments performed on linear molecules. MFPADs were then computed using single-center expansion techniques within the fixed-nuclei frozen-core Hartree-Fock approximation. The computed cross sections for ionization to the (1a2)-1 b 3A2 state show a strong propensity for ionization with the polarization of the light perpendicular to the plane of the molecule, whereas the ionization to the (4a1)-1 3A1 state of the ion is of similar intensity for all orientations of the polarization of the light in the molecular frame. These qualitative features of the MFPAD are also evident in the RFPAD. The RFPAD for ionization leading to the (1a2)-1 b 3A2 state is strongly peaked in the perpendicular orientation, whereas the RFPAD for ionization leading to the (4a2)-1 3A1 state is much more nearly isotropic. Comparison between experimental and theoretical RFPADs indicates that the recoil angle for NO+ fragments is approximately 50 degrees relative to the symmetry axis of the initial C2v symmetry of the NO2 molecule in the ionization leading to the (1a2)-1 b 3A2 state and the recoil angle is approximately 120 degrees for the O+ fragment for ionization leading to the (4a1)-1 3A1 state.

Molecular frame photoelectron emission in the presence of autoionizing resonances.

We have measured the angular distribution of valence-shell photoelectrons excited by circularly polarized light from fixed-in-space N2O molecules, near to and on top of resonances due to Rydberg states embedded in the ionization continuum. The sign of the circular dichroism for ionization into the N2O+ (B2Pi, (1pi)-1) state is reversed on top of the lowest dominant resonances. Measured angular distributions are well predicted by state-of-the-art multichannel configuration interaction calculations. The change in sign of the circular dichroism at the peak of the resonance is the result of a rapid change in the phases of resonant dipole matrix elements by a factor of 2pi as the energy is scanned across the resonance.

Comment on a proposed draft protocol for the European Convention on Biomedicine relating to research on the human embryo and fetus.

Judge Christian Byk renders service to the Steering Committee on Bioethics of the Council of Europe (CDBI) by proposing a draft of the protocol destined to fill in a gap in international law on the status of the human embryo. This proposal, printed in a previous issue of the Journal of Medical Ethics deserves nevertheless to be questioned on important points. Is Christian Byk proposing to legalise research on human embryos not only in vitro but also in utero?