Differential Transfer Ionization Cross Sections for 50175-keV Proton-Helium Collisions

We have measured coincidences between neutralized projectiles and He recoil ions for 50175-keV proton-helium collisions. From the data we obtained transfer ionization (TI) cross sections differential in the projectile scattering angle. Laboratory scattering angles range from 0 to 2.0 mrad. The experimental method allowed separation of the postcollision charge states of the target atoms. The ratio of the cross sections for TI to the sum of TI and single capture, F, is presented as a function of projectile scattering angle. Comparison is made to previous measurements of this ratio where data is available. The differential cross sections are compared to dynamical classical trajectory Monte Carlo (dCTMC) calculations. Agreement in the shape of the differential cross sections is good between the theory and measurement over the entire energy range

Differential Cross Sections for the Production of Highly Charged Recoil Ions in 10 Mev F⁸⁺ → Ne Collisions

Using recoil-ion momentum spectroscopy (rims), we have measured differential cross sections for the production of highly charged Ne ions in collisions with 10 MeV Fs+ as a function of the recoil-ion transverse momentum and charge state. In addition, the outgoing projectiles were charge-state analyzed and detected in coincidence with the Ne recoil-ions. Thus, different reaction channels like direct ionization, single- and double-electron capture by the projectile could be separated. The recoil-ion transverse momentum p£ was determined with an accuracy comparable to a projectile scattering angle resolution of 2.5 x 10 5 rad. The experimental data are compared to results of classical many-particle (mctmc) and semiclassical quantum-statistical calculations. © 1994 IOP Publication Ltd

Target Dependence of Binary Encounter Electron Peak Anomalies in Collisions of Partially Stripped Heavy Ions with Molecular Hydrogen and Noble Gases

A systematic search was performed for the manifestation of quantum interference effects in the shape and angular distribution of the binary-encounter electron peak in collisions of partially stripped, or structured, heavy ions with noble gases and molecular hydrogen. The ionic species investigated were Cu5+,19+, I7+,23+, Au11+,29+ and U13+, all at the same nominal velocity equivalent to 0.6 MeV amu-1. Experimental double-differential cross sections for secondary electron emission in the binary encounter energy region are compared with a simple model based on the elastic scattering of quasi-free target electrons in the projectile field as well as with results of impulse approximation (IA) calculations. While these calculations provide a good qualitative overall description of the observed quantum effects for noble gas targets, this is not the case for H2 targets. An attempt was made to incorporate target molecular structure into the impulse approximation code by allowing the binary electron amplitudes from each of the hydrogen atoms, assumed to constitute the H2 molecule, to interfere. This approach, while demonstrating the strong influence of molecular orientation upon the intermediate energy region of the cross sections, did not meet with success, thereby indicating the necessity to consider the final-state interaction of the binary electron with the two protons of the residual H2+ or H22+ target. © 1995 IOP Publishing Ltd

State Selective Scattering Angle Dependent Capture Cross Sections Measured by Cold Target Recoil Ion Momentum Spectroscopy

We have developed a new kind of recoil ion momentum spectroscopy technique, using a precooled supersonic gas jet target, to determine state selective, scattering angle dependent cross sections for swift ion-atom collisions ( 0. 25 , ..., , 1 MeV He2+ on He), by measuring the transverse and longitudinal momentum of the recoil ion. A longitudinal momentum resolution of ± 0.13 a. u. was achieved, about a factor of 30 better than ever obtained before, which enables a clear separation of K and L shell capture. In the transverse direction a resolution corresponding to a projectile scattering angle uncertainty of Δ ϑ P = ±1 μ rad was obtained

The timing of umbilical cord clamping at birth: physiological considerations

While it is now recognized that umbilical cord clamping (UCC) at birth is not necessarily an innocuous act, there is still much confusion concerning the potential benefits and harms of this common procedure. It is most commonly assumed that delaying UCC will automatically result in a time-dependent net placental-to-infant blood transfusion, irrespective of the infant’s physiological state. Whether or not this occurs, will likely depend on the infant’s physiological state and not on the amount of time that has elapsed between birth and umbilical cord clamping (UCC). However, we believe that this is an overly simplistic view of what can occur during delayed UCC and ignores the benefits associated with maintaining the infant’s venous return and cardiac output during transition. Recent experimental evidence and observations in humans have provided compelling evidence to demonstrate that time is not a major factor influencing placental-to-infant blood transfusion after birth. Indeed, there are many factors that influence blood flow in the umbilical vessels after birth, which depending on the dominating factors could potentially result in infant-to-placental blood transfusion. The most dominant factors that influence umbilical artery and venous blood flows after birth are lung aeration, spontaneous inspirations, crying and uterine contractions. It is still not entirely clear whether gravity differentially alters umbilical artery and venous flows, although the available data suggests that its influence, if present, is minimal. While there is much support for delaying UCC at birth, much of the debate has focused on a time-based approach, which we believe is misguided. While a time-based approach is much easier and convenient for the caregiver, ignoring the infant’s physiology during delayed UCC can potentially be counter-productive for the infant

Aligning research to meet policy objectives for migrant families: an example from Canada

<p>Abstract</p> <p>Background</p> <p>'Evidence-based policy making' for immigrants is a complicated undertaking. In striving toward this goal, federal Canadian partners created the <it>Metropolis Project </it>in 1995 to optimize a two-way transfer of knowledge (researchers – policy makers) within five Canadian Centres of Excellence focused on migrants newly arrived in Canada. Most recently, <it>Metropolis </it>federal partners, including the Public Health Agency of Canada, defined one of six research priority areas as, immigrant 'families, children, and youth'. In order to build on previous work in the partnership, we sought to determine what has been studied within this research-policy partnership about immigrant 'families, children, and youth' since its inception.</p> <p>Methods</p> <p>Annual reports and working papers produced in the five Centres of Excellence between 1996–2006 were culled. Data on academic works were extracted, results coded according to eleven stated federal policy priority themes, and analyzed descriptively.</p> <p>Results</p> <p>139 academic works were reviewed. All federal priority themes, but few specific policy questions were addressed. The greatest volume of policy relevant works were identified for <it>Services </it>(n = 42) and <it>Education and Cultural Identity </it>(n = 39) priority themes.</p> <p>Conclusion</p> <p>Research conducted within the last 10 years is available to inform certain, not all, federal policy questions. Greater specificity in federal priorities can be expected to more clearly direct future research within this policy-research partnership.</p

Alcohol exposure during late gestation: Multiple developmental outcomes in sheep

Alcohol consumption during pregnancy remains common in many countries. Exposure to even low amounts of alcohol (i.e. ethanol) in pregnancy can lead to the heterogeneous fetal alcohol spectrum disorders (FASD), while heavy alcohol consumption can result in the fetal alcohol syndrome (FAS). FAS is characterized by cerebral dysfunction, growth restriction and craniofacial malformations. However, the effects of lower doses of alcohol during pregnancy, such as those that lead to FASD, are less well understood. In this article, we discuss the findings of recent studies performed in our laboratories on the effects of fetal alcohol exposure using sheep, in which we investigated the effects of late gestational alcohol exposure on the developing brain, arteries, kidneys, heart and lungs. Our studies indicate that alcohol exposure in late gestation can (1) affect cerebral white matter development and increase the risk of hemorrhage in the fetal brain, (2) cause left ventricular hypertrophy with evidence of altered cardiomyocyte maturation, (3) lead to a decrease in nephron number in the kidney, (4) cause altered arterial wall stiffness and endothelial and smooth muscle function and (5) result in altered surfactant protein mRNA expression, surfactant phospholipid composition and pro-inflammatory cytokine mRNA expression in the lung. These findings suggest that fetal alcohol exposure in late gestation can affect multiple organs, potentially increasing the risk of disease and organ dysfunction in later life

Simple methodology for the quantitative analysis of fatty acids in human red blood cells

In the last years, there has been an increasing interest in evaluating possible relations between fatty acid (FA) patterns and the risk for chronic diseases. Due to the long life span (120 days) of red blood cells (RBCs), their FA profile reflects a longer term dietary intake and was recently suggested to be used as an appropriate biomarker to investigate correlations between FA metabolism and diseases. Therefore, the aim of this work was to develop and validate a simple and fast methodology for the quantification of a broad range of FAs in RBCs using gas chromatography with flame ionization detector, as a more common and affordable equipment suitable for biomedical and nutritional studies including a large number of samples. For this purpose, different sample preparation protocols were tested and compared, including a classic two-step method (Folch method) with modifications and different one-step methods, in which lipid extraction and derivatization were performed simultaneously. For the one-step methods, different methylation periods and the inclusion of a saponification reaction were evaluated. Differences in absolute FA concentrations were observed among the tested methods, in particular for some metabolically relevant FAs such as trans elaidic acid and eicosapentaenoic acid. The one-step method with saponification and 60 min of methylation time was selected since it allowed the identification of a higher number of FAs, and was further submitted to in-house validation. The proposed methodology provides a simple, fast and accurate tool to quantitatively analyse FAs in human RBCs, useful for clinical and nutritional studies.This work received financial support from the European Union (FEDER funds through COMPETE) and National Funds (FCT, Fundação para a Ciência e Tecnologia) through project PTDC/SAU-ENB/116929/2010 and EXPL/EMS-SIS/2215/2013. ROR acknowledges PhD scholarship SFRH/BD/97658/2013 attributed by FCT (Fundação para a Ciência e Tecnologia).info:eu-repo/semantics/publishedVersio

Effects of selective serotonin reuptake inhibitor treatment on plasma oxytocin and cortisol in major depressive disorder

Background: Oxytocin is known for its capacity to facilitate social bonding, reduce anxiety and for its actions on the stress hypothalamopituitary adrenal (HPA) axis. Since oxytocin can physiologically suppress activity of the HPA axis, clinical applications of this neuropeptide have been proposed in conditions where the function of the HPA axis is dysregulated. One such condition is major depressive disorder (MDD). Dysregulation of the HPA system is the most prominent endocrine change seen with MDD, and normalizing the HPA axis is one of the major targets of recent treatments. The potential clinical application of oxytocin in MDD requires improved understanding of its relationship to the symptoms and underlying pathophysiology of MDD. Previous research has investigated potential correlations between oxytocin and symptoms of MDD, including a link between oxytocin and treatment related symptom reduction. The outcomes of studies investigating whether antidepressive treatment (pharmacological and non-pharmacological) influences oxytocin concentrations in MDD, have produced conflicting outcomes. These outcomes suggest the need for an investigation of the influence of a single treatment class on oxytocin concentrations, to determine whether there is a relationship between oxytocin, the HPA axis (e.g., oxytocin and cortisol) and MDD. Our objective was to measure oxytocin and cortisol in patients with MDD before and following treatment with selective serotonin reuptake inhibitors, SSRI. Method: We sampled blood from arterial plasma. Patients with MDD were studied at the same time twice; pre- and post- 12 weeks treatment, in an unblinded sequential design (clinicaltrials.govNCT00168493). Results: Results did not reveal differences in oxytocin or cortisol concentrations before relative to following SSRI treatment, and there were no significant relationships between oxytocin and cortisol, or these two physiological variables and psychological symptom scores, before or after treatment. Conclusions: These outcomes demonstrate that symptoms of MDD were reduced following effective treatment with an SSRI, and further, stress physiology was unlikely to be a key factor in this outcome. Further research is required to discriminate potential differences in underlying stress physiology for individuals with MDD who respond to antidepressant treatment, relative to those who experience treatment resistance.Charlotte Keating, Tye Dawood, David A Barton, Gavin W Lambert and Alan J Tilbroo