We aimed to evaluate the site of placentation on the pregnancy outcomes of patients with placenta previa.
This retrospective study included 678 cases of placenta previa. Basic information and ...pregnancy outcome data were collected. Differences between the different placenta previa positions and pregnancy outcomes were compared using the chi-square and independent t tests. Logistic and multiple regression analyses were used to calculate the odds ratios (ORs) to determine the risk factors for PAS disorders and postpartum hemorrhage and evaluate the effect of placental attachment site on pregnancy outcomes.
There was no significant difference between the PAS disorders rate and the incidence of complete placenta previa depending on the type of placentation; however, placental attachment site influenced the pregnancy outcome. Placental attachment to the anterior wall was associated with shorter gestational age, low birth weight, lower Apgar score, higher prenatal bleeding rate, increased postpartum hemorrhage, longer duration of hospitalization, and higher blood transfusion and hysterectomy rates compared to cases with lateral/posterior wall placenta. Placental attachment at the incision site of a previous cesarean section significantly increased the incidence of complete placenta previa and PAS disorders compared with placental attachment at a site without incision, but did not significantly influence pregnancy outcomes. Placental attachment to the anterior wall was an independent risk factor for postpartum hemorrhage in patients with placenta previa. Placental attachment to a previous incision site was an independent risk factor for PAS disorders.
The site of placental attachment in patients with placenta previa has an important influence on the pregnancy outcome. When the placenta is located on the anterior wall, clinicians should pay attention to the adverse pregnancy outcomes and the possibility of massive postpartum hemorrhage. In cases of placental attachment to the uterine incision site, physicians should be highly vigilant regarding the occurrence of PAS disorders.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
We solved analytically viscous two-dimensional (2D) fluid equations for accretion and outflows in spherical polar coordinates (r, θ, φ) and obtained explicitly flow variables in r- and θ-directions ...around black holes (BHs). We investigated global transonic advection-dominated accretion flow (ADAF) solutions in an r-direction on an equatorial plane using Paczy ski-Wiita potential. We used radial flow variables of ADAFs with symmetric conditions on the equatorial plane as initial values for integration in the θ-direction. In the study of 2D disk structure, we used two azimuthal components of viscous stress tensors-namely, and . Interestingly, we found that the whole advective disk does not participate in outflow generation, and the outflows form close to the BHs. Normally, outflow strength increased with increasing viscosity parameter ( 1), mass-loss parameter (s), and decreasing gas pressure ratio (β). The outflow region increased with increasing s, 1 for and decreasing 2 for . The is effective in angular momentum transportation at high latitude and outflows collimation along an axis of symmetry, since it changes polar velocity ( ) of the flow. The outflow emission is also affected by the ADAF size and decreases with it. Transonic surfaces formed for both inflows ( , very close to BH) and outflows ( ). We also explored no outflows, outflows, and failed outflows regions, which mainly depend on the viscosity parameters.
Combined cooling, heating, and power (CCHP) systems have been widely applied in various kinds of buildings. Most operation strategies for CCHP microgrids are designed based on day-ahead profiles. ...However, prediction error for renewable energy resources (RES) and load leads to suboptimal operation in dispatch scheduling. In this paper, we propose an online optimal operation approach for CCHP microgrids based on model predictive control with feedback correction to compensate for prediction error. This approach includes two hierarchies: 1) rolling optimization; and 2) feedback correction. In the rolling part, a hybrid algorithm based on integrating time series analysis and Kalman filters is used to forecast the power for RES and load. A rolling optimization model is established to schedule operation according to the latest forecast information. The rolling dispatch scheduling is then adjusted based on ultra-short-term error prediction. The feedback correction model is applied to minimize the adjustments and to compensate for prediction error. A case study demonstrates the effectiveness of the proposed approach with better matching between demand and supply.
Abstract
The timescales of the variabilities in changing look (CL) active galactic nuclei (AGNs) are usually on the order of years to tens of years (some of them are even shorter than one year), ...which is much shorter than the viscous timescale of a standard thin accretion disk. This implies that the variabilities of CL AGNs cannot be reproduced by varying the mass accretion rate of the thin disk. In this work, we employ a magnetic accretion disk-outflow model to calculate the inflow time of the disk predominantly driven by magnetic outflows. In this model, most angular momentum of the gas in the disk is carried away by the outflows, and therefore its radial velocity can be substantially higher than that of a conventional viscous disk. Our calculations show that the inflow time of such a disk with outflows can be around several years to tens of years. The calculated spectra of the disk with outflows can fit the observed spectra of a CL AGN Mrk 1018 quite well both in the low and high states. The derived inflow time of such a disk with outflows is around 5 yr in the high state, while it becomes ∼20 yr in the low state, which is roughly consistent with the observations of the variabilities in Mrk 1018.
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•Inhibition of RIP1K produces neuroprotection against focal cerebral ischemia.•Inhibition of RIP1K directly protects ischemic neurons and astrocytes.•Inhibition of RIP1K decreases ...RIP1K–RIP3K complex formation.•Inhibition of RIP1K reduces LC3II and active cathepsin B levels and lysosomal membrane permeability.
Although the receptor-interacting protein 1 kinase (RIP1K)-regulated necroptosis can be evoked by cerebral ischemia, the effects of RIP1K in mediating neuronal and astrocytic cell death and the underlying mechanisms remain poorly understood. This study evaluates the contribution of RIP1K to ischemic stroke-induced neuronal and astrocytic cell death, and the activation of autophagic-lysosomal pathway. Using an in vitro oxygen and glucose deprivation (OGD) in primary cultured neurons or astrocytes and a permanent middle cerebral artery occlusion (pMCAO) model in rats or mice, we observed the role of RIP1K in the ischemic neuronal and astrocytic cell death and the underlying mechanisms by pharmacological or genetic inhibition of RIP1K. pMCAO or OGD condition led to an increase in RIP1K, RIP3K and RIP1K–RIP3K complex. RIP1K knockdown or necrostatin-1 (Nec-1, a specific inhibitor of RIP1K) treatment reduced infarct volume, improved neurological deficits, increased microtubule-associated protein 2 (MAP2) and glial fibrillary acidic protein (GFAP) levels, and attenuated neuronal or astrocytic necrotic cell death in the ischemic cortex. RIP1K knockdown decreased RIP1K–RIP3K complex formation, light chain 3 II (LC3II) and active cathepsin B levels and lysosomal membrane permeability (LMP). Furthermore, a combination of Nec-1 and an inhibitor of autophagy or cathepsin B produced an enhancement of protective effect on neuronal or astrocytic cell death. RIP1K-mediated necroptosis may play important roles in ischemia-induced neuronal and astrocytic cell death through the activation of autophagic-lysosomal pathway.
A novel and unusual palladium‐catalyzed 4+2 annulation of cyclopropenes with benzosilacyclobutanes is reported. This reaction occurred through chemoselective Si−C(sp2) bond activation in synergy with ...ring expansion/insertion of cyclopropenes to form new C(sp2)−C(sp3) and Si−C(sp3) bonds. An array of previously elusive bicyclic skeleton with high strain, silabicyclo4.1.0heptanes, were formed in good yields with excellent diastereoselectivity under mild conditions. An asymmetric version of the reaction with a chiral phosphoramidite ligand furnished a variety of chiral bicyclic silaheterocycle derivatives with good enantioselectivity (up to 95.5:4.5 er). Owing to the mild reaction conditions, the good stereoselectivity profile, and the ready availability of the functionalized precursors, this process constitutes a useful and straightforward strategy for the synthesis of densely functionalized silacycles.
When Si−C meets C=C bond activation: Cyclopropenes were functionalized stereoselectively with benzosilacyclobutanes by palladium‐catalyzed Si−C(sp2) bond activation and a ring‐expansion/4+2 annulation sequence to form new C(sp2)−C(sp3) and Si−C(sp3) bonds of silabicyclo4.1.0heptanes. The transformation provided an array of these previously elusive highly strained bicyclic skeletons in good yields with high selectivity (see scheme).
Abstract
We construct an analytical black hole accretion disk model that incorporates both magnetic pressure and disk wind, which are found to be important from numerical simulations. A saturated ...magnetic pressure that relates the Alfvén velocity with local Keplerian velocity and gas sound speed is assumed in addition to radiation and gas pressures. The mass accretion rate is assumed to have a power-law form in response to mass loss in the wind. We find three sets of self-consistent solutions that are thermally stable and satisfy the model assumptions. At high accretion rates, the disk is geometrically and optically thick, resembling the slim disk solution. At relatively low accretion rates, our model predicts an accretion flow consisting of a geometrically thin and optically thick outer disk (similar to the standard disk), and a geometrically thick and optically thin inner disk (similar to the advection-dominated accretion flow, or ADAF). Thus, this is a natural solution for a truncated disk connected with an inner ADAF, which has been proposed to explain some observations. The magnetic pressure plays a more important role than the outflow in shaping the disk structure. The observed disk luminosity tends to saturate around 8 times the Eddington limit, suggesting that supercritical accretion onto black holes can be used for a black hole mass estimate, or a standard candle with known black hole masses.
Winds can ‘blow up’ AGN accretion disc sizes Sun, Mouyuan; Xue, Yongquan; Trump, Jonathan R ...
Monthly Notices of the Royal Astronomical Society,
01/2019, Letnik:
482, Številka:
2
Journal Article
Herein, we reported an efficient and stable Z-scheme β-Bi2O3@g-C3N4 core/shell nanocomposite for photocatalytic degradation of recalcitrant antibiotic tetracycline.
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•The new ...β-Bi2O3@g-C3N4 core/shell nanocomposites were firstly fabricated.•The core/shell photocatalysts exhibited excellent photoactivity for TC degradation.•The enhanced photocatalytic mechanism is a Z-scheme charge transfer pathway.•The promising nanomaterials can be used for removal of antibiotic pollutants.
The elimination of recalcitrant pollutants from wastewater using core/shell structure photocatalysts has received much attention in the area of environmental science. In this study, novel β-Bi2O3@g-C3N4 core/shell nanocomposites were firstly fabricated via a feasible self-assembly methodology, in which β-Bi2O3 nanoparticles were chosen as the host material for g-C3N4 loading. The photocatalytic activity of the samples were evaluated by the degradation of antibiotic tetracycline (TC) under visible-light illumination (λ > 420 nm). Compared to the pristine β-Bi2O3 and g-C3N4, the prepared core/shell nanocomposites showed remarkably enhanced photocatalytic performance towards TC degradation in aqueous solution. Eventually, the 5 wt% g-C3N4 loaded core/shell sample (5%CN@BO) exhibited the optimum photocatalytic efficiency, and its rate constant (k = 0.0311 min−1) for TC degradation is much higher than lots of the previously reported photocatalysts. In addition, the as-synthesized 5%CN@BO also displayed excellent photostability for degradation of TC even after 5 times recycling tests. The highly visible-light-induced photoreactivity is ascribed to the formation of a core/shell Z-scheme heterojunction, which could significantly accelerate the separation of photoinduced electron-hole pairs and prolong the lifetime of charge carriers. This work provides an efficient core/shell nanomaterial for removal of antibiotic pollutants and will be useful for design of other core/shell photocatalysts.
Although lysine acetylation is now recognized as a general protein modification for both histones and non-histone proteins, the mechanisms of acetylation-mediated actions are not completely ...understood. Acetylation of the C-terminal domain (CTD) of p53 (also known as TP53) was an early example of non-histone protein acetylation and its precise role remains unclear. Lysine acetylation often creates binding sites for bromodomain-containing 'reader' proteins. Here we use a proteomic screen to identify the oncoprotein SET as a major cellular factor whose binding with p53 is dependent on CTD acetylation status. SET profoundly inhibits p53 transcriptional activity in unstressed cells, but SET-mediated repression is abolished by stress-induced acetylation of p53 CTD. Moreover, loss of the interaction with SET activates p53, resulting in tumour regression in mouse xenograft models. Notably, the acidic domain of SET acts as a 'reader' for the unacetylated CTD of p53 and this mechanism of acetylation-dependent regulation is widespread in nature. For example, acetylation of p53 also modulates its interactions with similar acidic domains found in other p53 regulators including VPRBP (also known as DCAF1), DAXX and PELP1 (refs. 7, 8, 9), and computational analysis of the proteome has identified numerous proteins with the potential to serve as acidic domain readers and lysine-rich ligands. Unlike bromodomain readers, which preferentially bind the acetylated forms of their cognate ligands, the acidic domain readers specifically recognize the unacetylated forms of their ligands. Finally, the acetylation-dependent regulation of p53 was further validated in vivo by using a knock-in mouse model expressing an acetylation-mimicking form of p53. These results reveal that acidic-domain-containing factors act as a class of acetylation-dependent regulators by targeting p53 and, potentially, other proteins.
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