Please cite this paper as: Lee C, Lin S, Lin C, Shih J, Lin T, Su Y. Clinical utility of array comparative genomic hybridisation for prenatal diagnosis: a cohort study of 3171 pregnancies. BJOG ...2012;119:614–625.
Objective To evaluate the clinical value of prenatal array comparative genomic hybridisation (CGH) in screening for submicroscopic genomic imbalances.
Design Cross‐sectional study.
Setting Tertiary referral centre.
Population From June 2008 to February 2011, 3171 fetuses underwent prenatal array CGH testing and karyotyping at the National Taiwan University Hospital. Indications for invasive prenatal diagnosis included abnormal karyotype, abnormal ultrasound, advanced maternal age and parental anxiety.
Methods In all, 2497 fetuses were screened with 1‐Mb resolution bacterial artificial chromosome array‐based CGH, and 674 fetuses with 60‐K oligonucleotide array‐based CGH. Multiplex ligation‐dependent probe amplification, fluorescence in situ hybridization, or 105‐K oligonucleotide array CGH provided further confirmation.
Main outcome measure Copy number variations identified by array CGH.
Results Array CGH detected numerical chromosome anomalies in 37 (1.2%) fetuses, microdeletion/duplication in 34 (1.1%) fetuses, large deletion/duplication in 13 (0.4%) fetuses, benign copy number changes in 13 (0.4%) fetuses and variation of unknown clinical significance in five (0.2%) fetuses. Array CGH was effective in identifying submicroscopic genomic imbalance in fetuses with de novo balance translocations (2/17, 1.8%), supernumerary marker chromosomes (3/6, 50%), and abnormal prenatal ultrasound findings (33/194, 17.0%). Array CGH detected microdeletions/duplications in 12 fetuses with normal karyotype.
Conclusion Prenatal array CGH is effective in screening for submicroscopic genomic imbalance. Array CGH may add 8.2% to the diagnostic field, compared with conventional karyotyping, for fetuses with abnormal ultrasound results, and is particularly useful in fetuses with karyotypic balanced translocation or marker chromosomes. There is a 0.52% baseline risk of submicroscopic genomic imbalance, even in women with an uneventful prenatal examination.
Stellar Evolution in AGN Disks Cantiello, Matteo; Jermyn, Adam S.; Lin, Douglas N. C.
Astrophysical journal/The Astrophysical journal,
04/2021, Letnik:
910, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Abstract
Active galactic nuclei (AGNs) are powered by geometrically thin accretion disks surrounding a central supermassive black hole. Here we explore the evolution of stars embedded in these ...extreme astrophysical environments (AGN stars). Because AGN disks are much hotter and denser than most components of the interstellar medium, AGN stars are subject to very different boundary conditions than normal stars. They are also strongly affected by both mass accretion, which can run away given the vast mass of the disk, and mass loss due to super-Eddington winds. Moreover, chemical mixing plays a critical role in the evolution of these stars by allowing fresh hydrogen accreted from the disk to mix into their cores. We find that, depending on the local AGN density and sound speed and the duration of the AGN phase, AGN stars can rapidly become very massive (
M
> 100
M
⊙
). These stars undergo core collapse, leave behind compact remnants, and contribute to polluting the disk with heavy elements. We show that the evolution of AGN stars can have a profound impact on the evolution of AGN metallicities, as well as the production of gravitational wave sources observed by LIGO-Virgo. We point to our Galactic Center as a region well suited to testing some of our predictions for this exotic stellar evolutionary channel.
Current methods of chemical vapour deposition (CVD) of graphene on copper are complicated by multiple processing steps and by high temperatures required in both preparing the copper and inducing ...subsequent film growth. Here we demonstrate a plasma-enhanced CVD chemistry that enables the entire process to take place in a single step, at reduced temperatures (<420 °C), and in a matter of minutes. Growth on copper foils is found to nucleate from arrays of well-aligned domains, and the ensuing films possess sub-nanometre smoothness, excellent crystalline quality, low strain, few defects and room-temperature electrical mobility up to (6.0±1.0) × 10(4) cm(2) V(-1) s(-1), better than that of large, single-crystalline graphene derived from thermal CVD growth. These results indicate that elevated temperatures and crystalline substrates are not necessary for synthesizing high-quality graphene.
Galactic center black holes appear to be nearly universally surrounded by dense stellar clusters. When these black holes go through an active accretion phase, the multiple components of the accretion ...disk, stellar cluster, and black hole system all coexist. We analyze the effect of drag forces on highly eccentric stellar orbits incurred as stars puncture through the disk plane. Disk crossings dissipate orbital energy, drawing eccentric stars into more circular orbits. For high surface density disks, such as those found around black holes accreting near the Eddington mass accretion limit, the magnitude of this energy dissipation can be larger than the mean scatterings that stars receive by two-body relaxation. One implication of this is the presence of a disk "loss cone" for highly eccentric stellar orbits where the dissipation from disk interaction outweighs scatter via two-body relaxation. The disk loss cone is larger than the tidal disruption loss cone for near-Eddington black hole accretion rates. Stellar orbits within the disk loss cone are lost from the overall cluster as stellar orbits are circularized and stars are potentially ablated by their high-velocity impacts with the disk. We find, however, that the presence of the disk loss cone has a minimal effect on the overall rate of stellar tidal disruptions. Stars are still efficiently fed to the black hole from more-distant stellar orbits that receive large-enough per-orbit scatter to jump over the disk loss cone and end up tidally disrupted.
The questions of how planets form and how common Earth-like planets are can be addressed by measuring the distribution of exoplanet masses and orbital periods. We report the occurrence rate of ...close-in planets (with orbital periods less than 50 days), based on precise Doppler measurements of 166 Sun-like stars. We measured increasing planet occurrence with decreasing planet mass (M). Extrapolation of a power-law mass distribution fitted to our measurements, df/dlogM = 0.39 M⁻⁰.⁴⁸, predicts that 23% of stars harbor a close-in Earth-mass planet (ranging from 0.5 to 2.0 Earth masses). Theoretical models of planet formation predict a deficit of planets in the domain from 5 to 30 Earth masses and with orbital periods less than 50 days. This region of parameter space is in fact well populated, implying that such models need substantial revision.
The class of exotic Jupiter-mass planets that orbit very close to their parent stars were not explicitly expected before their discovery. The recently discovered transiting planet WASP-12b has a mass ...M = 1.4 ± 0.1 Jupiter masses (MJ), a mean orbital distance of only 3.1 stellar radii (meaning it is subject to intense tidal forces), and a period of 1.1 days. Its radius 1.79 ± 0.09RJ is unexpectedly large and its orbital eccentricity 0.049 ± 0.015 is even more surprising because such close orbits are usually quickly circularized. Here we report an analysis of its properties, which reveals that the planet is losing mass to its host star at a rate of about 10-7MJ per year. The planet's surface is distorted by the star's gravity and the light curve produced by its prolate shape will differ by about ten per cent from that of a spherical planet. We conclude that dissipation of the star's tidal perturbation in the planet's convective envelope provides the energy source for its large volume. We predict up to 10 mJy CO band-head (2.292 m) emission from a tenuous disk around the host star, made up of tidally stripped planetary gas. It may also contain a detectable resonant super-Earth, as a hypothetical perturber that continually stirs up WASP-12b's eccentricity.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Summary
Sarcopenia was reported to be significantly associated with osteoporosis. In this study, we reported for the first time that sarcopenia was an independent risk predictor of osteoporotic ...vertebral compression refractures (OVCRFs). Other risk factors of OVCRFs are low bone mass density T-scores, female sex, and advanced age.
Introduction
The purpose of this study was to investigate the association between osteoporotic vertebral compression refractures (OVCRFs) and sarcopenia, and to identify other risk factors of OVCRFs.
Methods
We evaluated 237 patients with osteoporotic vertebral compression fracture who underwent percutaneous kyphoplasty (PKP) in our hospital from August 2016 to December 2017. To diagnose sarcopenia, a cross-sectional computed tomography (CT) image at the inferior aspect of the third lumbar vertebra (L3) was selected for estimating muscle mass. Grip strength was used to assess muscle strength. Possible risk factors, such as age, sex, body mass index (BMI), bone mineral density (BMD), location of the treated vertebra, anterior-posterior ratio (AP ratio) of the fractured vertebra, cement leakage, and vacuum clefts, were assessed. The multivariable analysis was used to determine the risk factors of OVCRFs.
Results
During the follow-up period, OVCRFs occurred in 64 (27.0%) patients. Sarcopenia was present in 48 patients (20.3%), including 21 OVCRFs and 27 non-OVCRFs patients. Sarcopenia was significantly correlated with advanced age, lower BMI, lower BMD, and hypoalbuminemia. Compared with non-sarcopenic patients, sarcopenic patients had higher OVCRFs risk. In univariate analysis, sarcopenia (
p
= 0.003), female (
p
= 0.024), advanced age (≥ 75 years;
p
< 0.001), lower BMD (
p
< 0.001), lower BMI (
p
= 0.01), TL junction (vertebral levels at the thoracolumbar junction) (
p
= 0.01), cardiopulmonary comorbidity (
p
= 0.042), and hypoalbuminemia (
p
= 0.003) were associated with OVCRFs. Multivariable analysis revealed that sarcopenia (OR 2.271; 95% CI 1.069–4.824,
p
= 0.033), lower BMD (OR 1.968; 95% CI 1.350–2.868,
p
< 0.001), advanced age (≥ 75 years; OR 2.431; 95% CI 1.246–4.744,
p
= 0.009), and female sex (OR 4.666; 95% CI 1.400–15.552,
p
= 0.012) were independent risk predictors of OVCRFs.
Conclusions
Sarcopenia is an independent risk predictor of osteoporotic vertebral compression refractures. Other factors affecting OVCRFs are low BMD T-scores, female sex, and advanced age.
We address two outstanding issues in the sequential accretion scenario for gas giant planet formation, the retention of dust grains in the presence of gas drag and that of cores despite type I ...migration. The efficiency of these processes is determined by the disk structure. Theoretical models suggest that planets form in protostellar disk regions with an inactive neutral 'dead zone' near the midplane, sandwiched together by partially ionized surface layers where magnetorotational instability is active. Due to a transition in the abundance of dust grains, the active layer's thickness decreases abruptly near the ice line. Over a range of modest accretion rates (image10 super(-9) to 10 super(-8) image yr super(-1)), the change in the angular momentum transfer rate leads to local surface density and pressure distribution maxima near the ice line. The azimuthal velocity becomes super- Keplerian and the grains accumulate in this transition zone. This barrier locally retains protoplanetary cores and enhances the heavy-element surface density to the critical value needed to initiate efficient gas accretion. It leads to a preferred location and epoch of gas giant formation. We simulate and reproduce the observed frequency and mass-period distribution of gas giants around solar-type stars without having to greatly reduce the type I migration strength. The mass function of the short-period planets shows an enhanced population of super-Earths relative to hot Jupiters, and it can be utilized to calibrate the efficiency of type I migration and to extrapolate the fraction of stars with habitable terrestrial planets.
MicroRNAs (miRNAs) play important roles in tumorigenesis by regulating oncogenes and tumor-suppressor genes. In this study, miR-187 and miR-200a were found to be expressed at higher levels in ovarian ...cancers than in benign tumors. In patients with ovarian cancer, however, higher levels of miR-187 and miR-200a expression were paradoxically associated with better OS and recurrence-free survival. Further, multivariate analysis showed that miR-187 served as an independent prognostic factor for patients with ovarian cancer (n=176). Computational prediction and microarray results indicated that miR-187 directly targeted Disabled homolog-2 (Dab2), and luciferase reporter assays confirmed that the target site of miR-187 was located at the 3'-UTR of the Dab2 gene. Generally considered as a tumor-suppressor gene, Dab2 may actually promote tumor progression in advanced cancers through epithelial-to-mesenchymal transition (EMT). Ectopic expression of miR-187 in cancer cells promoted cell proliferation, but continued overexpression of miR-187 suppressed Dab2 and inhibited migration. Suppression of miR-187 upregulated Dab2, which, by inhibiting E-cadherin levels while stimulating vimentin and phospho-FAK levels, promoted EMT. Reduced ovarian cancer Dab2 histoscores correlated with high miR-187 levels and improved outcomes of patients. Collectively, these results demonstrate distinct dual roles of Dab2 in cell proliferation and tumor progression. In the initial steps of tumorigenesis, upregulated miR-187 suppresses Dab2, promoting cell proliferation. During the later stages, however, continued increased levels of miR-187 inhibits the Dab2-dependent EMT that is associated with tumor invasiveness, which is presumed to be the reason why cancers with high miR-187 levels were associated with better survivals.
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