Childhood cholelithiasis in a district hospital Cozcolluela Cabrejas, M R; Sanz Salanova, L A; Martínez-Berganza Asensio, M T ...
Anales de pediatría (Barcelona, Spain : 2003)
66, Številka:
6
Journal Article
Recenzirano
Cholelithiasis is a rare finding in children, even though recent series show increased detection of this disease. A retrospective study was performed in children with a diagnosis of cholelithiasis ...between 1993 and 2005 in the Reina Sofia Hospital in Tudela (Spain). Eighteen patients with cholelithiasis and three with biliary sludge were detected. Predisposing factors for cholelithiasis were prematurity and parenteral nutrition (one patient), sepsis (two patients), obesity (one patient), and a family history of the disease (one patient). The disease was idiopathic in 11 patients. Gallstones were detected in two patients presenting with appendicular symptoms. One child with biliary sludge had received treatment with ceftriaxone as a predisposing factor. All patients were diagnosed by ultrasound. Plain abdominal X-ray detected lithiasis in 12 of the 15 patients (80 %) with cholelithiasis who underwent this procedure. The most frequent symptoms were abdominal pain (seven patients), abdominal pain and vomiting (five patients), and diarrhea (one patient). Two patients presented with appendicular symptoms. Fourteen patients underwent surgery (open cholecystectomy in two and laparoscopic cholecystectomy in 12). None of the patients required emergency surgery. Cholelithiasis in children is an unusual finding, but is not exceptional and is associated with nonspecific symptoms. Plain abdominal X-ray is useful in diagnosis but the main diagnostic technique is ultrasonography.
Thanks to decades of observations using HST, the structure of galaxies at redshift \(z>2\) has been widely studied in the rest-frame ultraviolet regime, which traces recent star formation from young ...stellar populations. But, we still have little information about the spatial distribution of the older, more evolved, stellar populations, constrained by the rest-frame infrared portion of galaxies' spectral energy distribution. We present the morphological characterization of a sample of 21 massive galaxies (\(\log(M_{\star}/M_{\odot})>9.5\)) at redshift \(3<z<5.5\). These galaxies are observed as part of the GTO program MIDIS with the Mid-Infrared Instrument (MIRI) onboard JWST. The deep MIRI 5.6~\(\mu\)m imaging allows us to characterize for the first time the rest-frame near-infrared structure of galaxies beyond cosmic noon, at higher redshifts than possible with NIRCam, tracing their older stellar populations. We derive the galaxies' non-parametric morphology and model the galaxies' light distribution with a Sérsic component. We find that at \(z>3\) massive galaxies show a smooth distribution of their rest-infrared light, strongly supporting the increasing number of regular disk galaxies already in place at early epochs. On the contrary, the ultraviolet structure obtained from HST observations is generally more irregular, catching the most recent episodes of star formation. Importantly, we find a segregation of morphologies across cosmic time, having massive galaxies at redshift \(z>4\) later-type morphologies compared to \(z\sim3\) galaxies. These findings suggest a transition phase in galaxy assembly and central mass build up already taking place at \(z\sim3-4\). MIRI provides unique information about the structure of the mature stellar population of high-redshift galaxies, unveiling that massive galaxies beyond cosmic noon are prevalently compact disk galaxies with smooth mass distribution.
Despite the importance of the dusty star-forming galaxies (DSFGs) at \(z\)>2 for understanding the galaxy evolution in the early Universe, their stellar distributions traced by the near-IR emission ...were spatially unresolved until the arrival of the JWST. In this work we present, for the first time, a spatially-resolved morphological analysis of the rest-frame near-IR (~1.1-3.5\(\mu\)m) emission in DSFGs traced with the JWST/MIRI. In particular, we study the mature stellar component for the three DSFGs and a Lyman-break galaxy (LBG) present in an overdensity at \(z\)=4.05. Moreover, we use MIRI images along with UV to (sub)-mm ancillary photometric data to model their SEDs and extract their main physical properties. The sub-arcsec resolution MIRI images have revealed that the stellar component present a wide range of morphologies, from disc-like to compact and clump-dominated structures. These near-IR structures contrast with their UV emission, which is usually diffuse and off-centered. The SED fitting analysis shows that GN20 dominates the total SFR with a value ~2500 \(M_\odot\)yr\(^{-1}\) while GN20.2b has the highest stellar mass in the sample (\(M_*\)~2\(\times\)10\(^{11}\) \(M_\odot\)). The two DSFGs classified as LTGs (GN20 and GN20.2a) show high specific SFR (sSFR>30 Gyr\(^{-1}\)) placing them above the star-forming main sequence (SFMS) at z~4 by >0.5 dex while the ETG (i.e.,GN20.2b) is compatible with the high-mass end of the main sequence. When comparing with other DSFGs in overdensities at \(z\)~2-7 we observe that our objects present similar SFRs, depletion times and projected separations. Nevertheless, the effective radii computed for GN20 and GN20.2a are up to two times larger than those of isolated galaxies observed in CEERS and ALMA-HUDF at similar redshifts. We interpret this difference in size as an effect of rapid growth induced by the dense environment.
The effects of anions and electrode surface structure on the UPD of metal monolayers are illustrated with three different examples. In the first, we show that for Cu UPD on Pt
n(111)×(110) (
n=2, 3, ...5, 9 and 19) stepped surfaces in sulfuric acid medium, submonolayer amounts of underpotentially deposited copper induce the adsorption of (bi)sulfate in the vicinity of copper adatoms deposited on (110) step sites. The induced anion adsorption increases with terrace width up to a three Pt atoms wide terrace, suggesting that this is the minimum width to accommodate the copper adatom and the coadsorbed anion. In the second case we present data from simultaneous time-resolved surface X-ray scattering and chronoamperometric measurements of Cu UPD on Pt(111) electrodes in the presence of chloride anions. These studies demonstrate that the kinetics of formation of the incommensurate CuCl adlayer from the commensurate (1×1) Cu layer takes place in a much longer time scale than the current response. This is a clear indication of the temporal separation (resolution) between electrochemical events and processes associated with surface reorganization to achieve long-range periodic ordering. Finally, we consider the UPD of Hg on Au(111) electrodes with emphasis on the relationship between the partial charge retained by the mercury and anion adsorption. At the early stages of Hg UPD, when mercury is still partially charged, an ordered mercurous–sulfate bilayer structure is formed on the electrode surface. At more negative potentials, where mercury is almost fully discharged, two additional ordered hexagonal mercury adlayers are formed with little, if any, interactions with the anions, suggesting that the interactions between them are largely electrostatic in nature.
The NEXT experiment aims at searching for the hypothetical neutrinoless double-beta decay from the \({}^{136}\)Xe isotope using a high-purity xenon TPC. Efficient discrimination of the events through ...pattern recognition of the topology of primary ionisation tracks is a major requirement for the experiment. However, it is limited by the diffusion of electrons. It is known that the addition of a small fraction of a molecular gas to xenon reduces electron diffusion. On the other hand, the electroluminescence (EL) yield drops and the achievable energy resolution may be compromised. We have studied the effect of adding several molecular gases to xenon (CO\({}_{2}\), CH\({}_{4}\) and CF\({}_{4}\)) on the EL yield and energy resolution obtained in a small prototype of driftless gas proportional scintillation counter. We have compared our results on the scintillation characteristics (EL yield and energy resolution) with a microscopic simulation, obtaining the diffusion coefficients in those conditions as well. Accordingly, electron diffusion may be reduced from about 10 mm/\(\sqrt{\mathrm{m}}\) for pure xenon down to 2.5 mm/\(\sqrt{\mathrm{m}}\) using additive concentrations of about 0.05%, 0.2% and 0.02% for CO\({}_{2}\), CH\({}_{4}\) and CF\({}_{4}\), respectively. Our results show that CF\({}_{4}\) admixtures present the highest EL yield in those conditions, but very poor energy resolution as a result of huge fluctuations observed in the EL formation. CH\({}_{4}\) presents the best energy resolution despite the EL yield being the lowest. The results obtained with xenon admixtures are extrapolated to the operational conditions of the NEXT-100 TPC. CO\({}_{2}\) and CH\({}_{4}\) show potential as molecular additives in a large xenon TPC, CH\({}_{4}\) showing the best performance and stability to be used in the NEXT-100 TPC, with an extrapolated energy resolution of 0.4% at 2.45 MeV for concentrations below 0.4%.
Resputtering phenomena play an important role in the growth of carbon nitride films assisted with low energy N+2 ions. CNx films x ranging between 0 and 0.6, as determined by Auger electron ...spectroscopy (AES) have been prepared by dual ion beam sputtering and characterized by several techniques AES, Rutherford backscattering (RBS), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM), transmission electron diffraction (TED). In this work we have estimated the resputtering yields of carbon and nitrogen atoms in terms of the deposition rate and the surface composition, as determined by AES depth profiling and RBS measurements. Carbon resputtering yield in the order of 0.3 carbon atoms per incident N+2 ions and nitrogen re-emissions higher than 90% are obtained. A threshold is found for the arrival rate ratio (ARR) of N+2 ions to C atoms of about 3.0. Higher values of ARR will inhibit the growth of the film. The influence of the energy of assistance and the electric properties of the substrates in the resputtering process are also discussed.
Within the framework of xenon-based double beta decay experiments, we propose the possibility to improve the background rejection of an electroluminescent Time Projection Chamber (EL TPC) by reducing ...the diffusion of the drifting electrons while keeping nearly intact the energy resolution of a pure xenon EL TPC. Based on state-of-the-art microscopic simulations, a substantial addition of helium, around 10 or 15~\%, may reduce drastically the transverse diffusion down to 2.5~mm/\(\sqrt{\mathrm{m}}\) from the 10.5~mm/\(\sqrt{\mathrm{m}}\) of pure xenon. The longitudinal diffusion remains around 4~mm/\(\sqrt{\mathrm{m}}\). Light production studies have been performed as well. They show that the relative variation in energy resolution introduced by such a change does not exceed a few percent, which leaves the energy resolution practically unchanged. The technical caveats of using photomultipliers close to an helium atmosphere are also discussed in detail.
The measurement of the internal \(^{222}\)Rn activity in the NEXT-White detector during the so-called Run-II period with \(^{136}\)Xe-depleted xenon is discussed in detail, together with its ...implications for double beta decay searches in NEXT. The activity is measured through the alpha production rate induced in the fiducial volume by \(^{222}\)Rn and its alpha-emitting progeny. The specific activity is measured to be \((38.1\pm 2.2~\mathrm{(stat.)}\pm 5.9~\mathrm{(syst.)})\)~mBq/m\(^3\). Radon-induced electrons have also been characterized from the decay of the \(^{214}\)Bi daughter ions plating out on the cathode of the time projection chamber. From our studies, we conclude that radon-induced backgrounds are sufficiently low to enable a successful NEXT-100 physics program, as the projected rate contribution should not exceed 0.1~counts/yr in the neutrinoless double beta decay sample.
We study the stellar population properties of 182 spectroscopically-confirmed (MUSE/VLT) Lyman-\(\alpha\) emitters (LAEs) and 450 photometrically-selected Lyman-Break galaxies (LBGs) at z = 2.8 - 6.7 ...in the Hubble eXtreme Deep Field (XDF). Leveraging the combined power of HST and JWST NIRCam and MIRI observations, we analyse their rest-frame UV-through-near-IR spectral energy distributions (SEDs) with MIRI playing a crucial role in robustly assessing the LAE's stellar mass and ages. Our LAEs are low-mass objects (log\(_{10}\)(M\(_\star\)M\(_\odot\)) ~ 7.5), with little or no dust extinction (E(B - V) ~ 0.1) and a blue UV continuum slope (\(\beta\) ~ -2.2). While 75% of our LAEs are young (< 100 Myr), the remaining 25% have significantly older stellar populations (> 100 Myr). These old LAEs are statistically more massive, less extinct and have lower specific star formation rate (sSFR) compared to young LAEs. Besides, they populate the M\(_\star\) - SFR plane along the main-sequence (MS) of star-forming galaxies, while young LAEs populate the starburst region. The comparison between the LAEs properties to those of a stellar-mass matched sample of LBGs shows no statistical difference between these objects, except for the LBGs redder UV continuum slope and marginally larger E(B - V) values. Interestingly, 48% of the LBGs have ages < 10 Myr and are classified as starbursts, but lack detectable Ly\(\alpha\) emission. This is likely due to HI resonant scattering and/or selective dust extinction. Overall, we find that JWST observations are crucial in determining the properties of LAEs and shedding light on the properties and similarities between LAEs and LBGs.
