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Low birth weight programs diseases in adulthood, including adverse bone health. These diseases can have intergenerational and transgenerational origins, whereby transmission to subsequent generations occurs via both parental lines. Uteroplacental insufficiency surgery (Restricted) or sham surgery (Control) was performed on gestational day 18, in F0 Wistar–Kyoto rats. F1 Restricted males and females mated with breeders in order to generate F2 offspring of maternal and paternal lineages. F2 males and females were randomly selected for breeding to generate F3 offspring. F2 and F3 offspring did not have differences in birth weight irrespective of F1 low birth weight and parental line. Maternal line females had minor alterations to trabecular content and density at 6 months, these differences were not sustained at 12 months. Maternal line males had changes to trabecular content at 6 and 12 months; however, differences were no longer present at 16 months. Despite altered bone geometry at 12 and 16 months, bending strength remained unaffected at both ages. Bone health of paternal line females was not affected at 6 and 12 months. Paternal line males at 6 months had changes to trabecular and cortical content; cortical thickness, periosteal circumference and bending strength; however, these differences were no longer sustained at 12 and 16 months. Our data demonstrate that there is no transgenerational transmission of adverse bone health in F2 and F3 offspring, derived from low F1 birth weight females and males. Our results are novel, as bone health across generations and both parental lines has not been investigated in a model of low birth weight due to uteroplacental insufficiency.
The use of oxygen in emergency situations outside hospitals is limited by difficulties in supply. Low capacity cylinders (100-120 1) weigh 3-4 kg, and have cumbersome mechanisms for pressure and flow reduction. Disposable cylinders of oxygen from a chemical source create the possibility of the contents running out, and are fragile. Particularly when exposed to high pressures or temperature.
Mouth-to-mouth remains most rational and effective. Problems include aesthetic concern and exhaustion in rescuer. It is possible, however, to adapt a Brooke or a Safar airway for use with oxygen, by attaching a tube with tape near the proximal outlet of the airway. This apparatus has been tried on 4 patients during general anesthesia with thiopentone-succinylcholine-neuroleptics—for appendectomies using controlled ventilation with expired air with oxygen added. Tidal volumes of 350-500 ml of air/oxygen were delivered at a frequency of 6-8 breaths per minute. The nose was closed by a clip. Sellik's maneuver could prevent gastric inflation. The color of blood was normal, arterial pressure and pulse did not change, and skin was dry. No fatigue or other effects were reported by the anesthesiologist-“rescuer”. In outdoor use, where oxygen from a chemical source is used, the problems associated with the exothermic reaction can be limited by cylinder lagging with openings to disperse heat. A flow of O2 6-7 1/min is sufficient to support a critical situation. It allows O2 enrichment for mouth-to-mouth, mouth-to-mask, mouth-to-airway, or bag valve ventilation. Modest cost, and low weight allow large numbers to be stored for airport disasters, when resuscitation is performed on a large scale for many victims.
Large volumes of data and multiple computing platforms are now universal components of paediatric cardiovascular medicine, but are in a constant state of evolution. Often, multiple sets of related data reside in disconnected “silos”, resulting in clinical, administrative, and research activities that may be duplicative, inefficient, and at times inaccurate. Comprehensive and integrated data solutions are needed to facilitate these activities across congenital heart centres. We describe methodology, key considerations, successful use cases, and lessons learnt in developing an integrated data platform across our congenital heart centre.
The idea that a significant fraction of line emission in AGN comes directly from an accretion disk is attractive for several reasons – not least the obvious one of establishing the black hole paradigm. We performed a few consistency tests for the hypothesis that both FE Kα and Hα are emitted by an accretion disk.
The main results of this preliminary investigation are as follows. FE Kα is systematically much broader than Hα at FWHM, but the widths of the two lines are not correlated. For each of the 9 objects with FE Kα profile most consistent with disk emission, we computed the possible disk contribution on the basis of a weak field model. Although the Hα profiles are not consistent with disk model emission, rotational motion could still be the main broadening mechanism. We then compared disk inclinations deduced from FE Kα model profile fitting to the ones we derived from model fits of Hα. The inclination values are consistent. Finally, we found that a simple illumination model can produce both disk FE Kα and Hα emission, if a small fraction of continuum is scattered toward the disk to yield ionization parameter ξ > 10−2 ergs s−1 cm.
We conclude that the bulk FE Kα cannot be associated to the Broad Line Region. Albeit several radio-quiet Seyfert 1 objects show FE Kα profiles consistent with emission from the inner part of an illuminated accretion disk, the general situation remains unclear, as fits to line profiles require an unsatisfactory large range in model parameters like emissivity and inner and outer radii.
We present new observations of the quasar 4C 37.43 in the course of a more general study of broad-line profiles in radio-loud AGN. During the most recent observations it became obvious that the broad profile Hβ had changed significantly. Difference spectra show that a new blue component has appeared on the Hβ profile. The centroid of this new component is displaced about 2500 km s−1 from the rest frame [O III] λ5007. A corresponding blueshifted He IIλ4686 component may have also appeared.
The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) is a narrow-band imaging, very wide field cosmological survey. It will last 5 years and will observe 8500 sq. deg. of the sky. There will be 54 contiguous narrow-band filters of 145Å FWHM, from 3,500 to 10,000Å. Two broad-band filters will be added at the extremes, UV and IR, plus the 3–g, r, and i– SDSS filters. Thus, J-PAS can be an important tool to search for new planetary nebulae (PNe) at the halo, increasing their numbers, because only 14 of them have been convincingly identified in the literature. Halo PNe are able to reveal precious information for the study of stellar evolution and the early chemical conditions of the Galaxy. The characteristic low continuum and intense emission lines of PNe make them good objects to be searched by J-PAS. Though covering a significantly smaller sky area, data from the ALHAMBRA survey were used to test our J-PAS strategy to search for PNe. Our first results are shown in this contribution.
The earliest phases of Galactical chemical evolution and nucleosynthesis can be investigated by studying the old metal-poor stars. It has been recognized that a large fraction of metal-poor stars possess significant over-abundances of carbon relative to iron. Here we present the results of a 23-star homogeneously analyzed sample of metal-poor candidates from the Hamburg/ESO survey. We have derived abundances for a large number of elements ranging from Li to Pb. The sample includes four ultra metal-poor stars ([Fe/H] < −4.0), six CEMP-no stars, five CEMP-s stars, two CEMP-r stars and two CEMP-r/s stars. This broad variety of the sample stars gives us an unique opportunity to explore different abundance patterns at low metallicity.
A dominant astrophysical site for r-process, which is responsible for producing heavy neutron-capture elements, is unknown. Dwarf spheroidal galaxies around the Milky Way halo provide ideal laboratories to investigate the origin and evolution of r-process elements. We carried out high-resolution spectroscopic observations of three giant stars in the Draco dwarf spheroidal galaxy to estimate their europium abundances. We found that the upper-limits of [Eu/H] are very low in the range [Fe/H] < −2, while this ratio is nearly constant at higher metallicities. This trend is not well reproduced with models which assume that Eu is produced together with Fe by SNe, and may suggest the contribution from other objects such as neutron-star mergers.
Significant minorities of extremely metal-poor (EMP) halo stars exhibit dramatic excesses of neutron capture elements. The standard scenario for their origin is mass transfer and dilution in binary systems, but requires them to be binaries. If not, these excesses must have been implanted in them from birth by processes that are not included in current models of SN II chemical enrichment. The binary population of such EMP subgroups is a test of this scenario.
The group-III nitrides have become versatile semiconductors for short wavelength emitters, high temperature microwave transistors, photodetectors, and field emission tips. The processing of these materials is significant due to the unusually high bond energies that they possess. The dry and wet etching methods developed for these materials over the last few years are reviewed. High etch rates and highly anisotropic profiles obtained by inductively-coupled-plasma reactive ion etching are presented. Photoenhanced wet etching provides an alternative path to obtaining high etch rates without ion-induced damage. This method is shown to be suitable for device fabrication as well as for the estimation of dislocation densities in n-GaN. This has the potential of developing into a method for rapid evaluation of materials.
Interdiffusion of In and Ga is observed in InGaN multiple-quantum-well superlattices for annealing temperatures of 1250 to 1400°C. Hydrostatic pressures of up to 15 kbar were applied during the annealing treatments to prevent decomposition of the InGaN and GaN. In as-grown material, x-ray diffraction spectra show InGaN superlattice peaks up to the fourth order. After annealing at 1400°C for 15 min, only the zero-order InGaN peak is observed, a result of compositional disordering of the superlattice. Composition profiles from secondary ion mass spectrometry indicate significant diffusion of Mg from the p-type GaN layer into the quantum well region. This Mg diffusion may lead to an enhancement of superlattice disordering. For annealing temperatures between 1250 and 1300°C, a blue shift of the InGaN spontaneous emission peak is observed, consistent with interdiffusion of In and Ga in the quantum-well region.
We present a device fabrication technology and measurement results of both optically pumped and electrically injected InGaN/GaN-based distributed feedback (DFB) lasers operated at room temperature. For the optically pumped DFB laser, we demonstrate a complex coupling scheme for the first time, whereas the electrically injected device is based on normal index coupling. Threshold currents as low as 1.1 A were observed in 500 μm long and 10 μm wide devices. The 3rd order grating providing feedback was defined holographically and dry-etched into the upper waveguiding layer by chemically-assisted ion beam etching. Even when operating these lasers considerably above threshold, a spectrally narrow emission (3.5 Å) at wavelengths around 400 nm was seen.
Uteroplacental insufficiency resulting in intrauterine growth restriction has been associated with the development of cardiovascular disease, coronary heart disease and increased blood pressure, particularly in males. The molecular mechanisms that result in the programming of these phenotypes are not clear. This study investigated the expression of cardiac JAK/STAT signalling genes in growth restricted offspring born small due to uteroplacental insufficiency. Bilateral uterine vessel ligation was performed on day 18 of pregnancy to induce growth restriction (Restricted) or sham surgery (Control). Cardiac tissue at embryonic day (E) 20, postnatal day (PN) 1, PN7 and PN35 in male and female Wistar (WKY) rats (n=7–10 per group per age) was isolated and mRNA extracted. In the heart, there was an effect of age for males for all genes examined there was a decrease in expression after PN1. With females, JAK2 expression was significantly reduced after E20, while PI3K in females was increased at E30 and PN35. Further, mRNA expression was significantly altered in JAK/STAT signalling targets in Restricteds in a sex-specific manner. Compared with Controls, in males, JAK2 and STAT3 were significantly reduced in the Restricted, while in females SOCS3 was significantly increased and PI3K significantly decreased in the Restricted offspring. Finally, there were specific differences in the levels of gene expression within the JAK/STAT pathway when comparing males to females. Thus, growth restriction alters specific targets in the JAK/STAT signalling pathway, with altered JAK2 and STAT3 potentially contributing to the increased risk of cardiovascular disease in the growth restricted males.
Abnormalities in hippocampal–parahippocampal (H-PH) function are prominent features of schizophrenia and have been associated with deficits in episodic memory. However, it remains unclear whether these abnormalities represent a phenotype related to genetic risk for schizophrenia or whether they are related to disease state.
We investigated H-PH-mediated behavior and physiology, using blood oxygenation level-dependent functional magnetic resonance imaging (BOLD fMRI), during episodic memory in a sample of patients with schizophrenia, clinically unaffected siblings and healthy subjects.
Patients with schizophrenia and unaffected siblings displayed abnormalities in episodic memory performance. During an fMRI memory encoding task, both patients and siblings demonstrated a similar pattern of reduced H-PH engagement compared with healthy subjects.
Our findings suggest that the pathophysiological mechanism underlying the inability of patients with schizophrenia to properly engage the H-PH during episodic memory is related to genetic risk for the disorder. Therefore, H-PH dysfunction can be assumed as a schizophrenia susceptibility-related phenotype.
Emotion dysregulation is a key feature of schizophrenia, a brain disorder strongly associated with genetic risk and aberrant dopamine signalling. Dopamine is inactivated by catechol-O-methyltransferase (COMT), whose gene contains a functional polymorphism (COMT Val158Met) associated with differential activity of the enzyme and with brain physiology of emotion processing. The aim of the present study was to investigate whether genetic risk for schizophrenia and COMT Val158Met genotype interact on brain activity during implicit and explicit emotion processing.
A total of 25 patients with schizophrenia, 23 healthy siblings of patients and 24 comparison subjects genotyped for COMT Val158Met underwent functional magnetic resonance imaging during implicit and explicit processing of facial stimuli with negative emotional valence.
We found a main effect of diagnosis in the right amygdala, with decreased activity in patients and siblings compared with control subjects. Furthermore, a genotype × diagnosis interaction was found in the left middle frontal gyrus, such that the effect of genetic risk for schizophrenia was evident in the context of the Val/Val genotype only, i.e. the phenotype of reduced activity was present especially in Val/Val patients and siblings. Finally, a complete inversion of the COMT effect between patients and healthy subjects was found in the left striatum during explicit processing.
Overall, these results suggest complex interactions between genetically determined dopamine signalling and risk for schizophrenia on brain activity in the prefrontal cortex during emotion processing. On the other hand, the effects in the striatum may represent state-related epiphenomena of the disorder itself.
Nanostructuring has opened new ways to increase the thermoelectric performance of a host of materials, mainly by decreasing their thermal conductivity κ while preserving the Seebeck coefficient S and electrical conductivity σ. The thermoelectric properties of degenerated polycrystalline silicon films with nanocavities (NCs) have been studied as a function of annealing temperature upon isochronous annealings in argon carried out every 50°C in the range 500 – 1000°C which were used to modify the shape of the NCs. We found that presence of the NCs had no negative effect on the electronic properties of the system. The measured values of S and σ were close to those previously reported for the blank polycrystalline silicon films with the same doping level. The thermal conductivity was also found to be close to the value measured on the blank sample, about half of the reported value in polycrystals. This led to a power factor of 15.2 mWm-1K-2 and a figure of merit of 0.18 at 300 K.
Recent results on metastable semiconducting alloys, concerning in particular the growth of new Sn-based alloys (GaSb)1−x(Sn2)x and Gel−xSnx and the physical properties of (GaAs)1−x(Ge2)x and (GaSb)1−x(Ge2)x, are discussed. (GaSb)1−x(Sn2)x and Ge1−xSnx alloy films were grown with x-values as high as 0.20 and 0.15, respectively, well in excess of equilibrium Sn solid solubility limits (<1%) while epitaxial (GaAs)1−x(Ge2) and (GaSb)1−x(Ge2)x alloys were obtained on (100) GaAs at compositions ranging across the pseudobinary phase diagram. Low energy ion bombardment induced collisional mixing and preferential sputtering during film growth played a critical role in obtaining single phase alloys. An optimal ion energy, which depended on the ion flux and the alloy composition, was determined, allowing in most cases growth at temperatures T, sufficient for obtaining single crystal alloys on (100) GaAs and (100) Ge substrates. Decomposition of the Sn-based alloys occurred above a critical Ts- value via α-Sn-rich precipitates which were stable above the β-Sn melting point. X-ray diffraction, STEM, EXAFS, and Raman spectroscopy measurements, performed on single crystal (GaAs)1−x(Ge2)x and (GaSb)1−x(Ge2)x alloys, indicate that there is a transition in the long-range order from zincblende to diamond with increasing x while the short-range order remains perfect at all compositions, i.e. no V-V or III-Ill bonds are observed. These results are discussed in light of recent models which relate (GaAs)1−x(Ge2)x atomic structure to its band structure and optical properties.
The use of high dose carbon ion implantation in Si for the production of ultrathin membranes is investigated. Carbon implantations with doses up to 1018 cm-8 and energies up to 300 keV, at room temperature and 500°C were used, followed by 10 hours annealing at 1150°C. Structural and chemical analysis has been performed (including TEM, XPS, Raman and IR spectroscopies), and the etch properties have been investigated for KOH and TMAH etchants. It is found that doses higher than 1017 cm-2 are needed to obtain efficient etch-stop layers in TMAH, independently of the annealing conditions, while in contrast with previous work, it was not possible to obtain satisfactory results using KOH. According to this, ultrathin crystalline membranes (below 500 nm thick) with average surface roughness as low as 4.8 nm, measured by AFM, were obtained, and the structural analysis revealed the formation of a highly stable buried layer of crystalline β-SiC precipitates aligned with the Si matrix. These results corroborate the ability of high dose C ion implantation to obtain buried layers usable for micomachining applications.
The structural quality of GaN films grown by hydride vapor phase epitaxy (HVPE) was characterized by transmission electron microscopy (TEM), x-ray diffraction (XRD), and atomic force microscopy (AFM). Films were grown up to 40μm on sapphire with either a GaC1 pretreatment prior to growth or on a ZnO buffer layer. Dislocation densities were found to decrease with increasing film thickness. This is attributed to the mixed nature of the defects present in the film which enabled dislocation annihilation. The thickest film had a defect density of 5×107 dislocations/cm2.