| 2961. |
- Wang, X. J., et al.
(författare)
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Contrasting characteristics, changes, and linkages of permafrost between the Arctic and the Third Pole
- 2022
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Ingår i: Earth-Science Reviews. - : Elsevier BV. - 0012-8252. ; 230
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Tidskriftsartikel (refereegranskat)abstract
- Permafrost degradation poses serious threats to both natural and human systems through its influence on ecological-hydrological processes, infrastructure stability, and the climate system. The Arctic and the Third Pole (Tibetan Plateau, TP hereafter) are the two northern regions on Earth with the most extensive permafrost areas. However, there is a lack of systematic comparisons of permafrost characteristics and its climate and ecoenvironment between these two regions and their susceptibility to disturbances. This study provides a comprehensive review of the climate, ecosystem characteristics, ground temperature, permafrost extent, and active-layer thickness, as well as the past and future changes in permafrost in the Arctic and the TP. The potential consequences associated with permafrost degradation are also examined. Lastly, possible connections between the two regions through land-ocean-atmosphere interactions are explored. Both regions have experienced dramatic warming in recent decades, characterized by Arctic amplification and elevation-dependent warming on the TP. Permafrost temperatures have increased more rapidly in the Arctic than on the TP, and will likely be reinforced under a future high emission scenario. Near-surface permafrost extents are projected to shrink in both regions in the coming decades, with a more dramatic decline in the TP. The active layer on the TP is thicker and has substantially deepened, and is projected to thicken more than in the Arctic. Widespread permafrost degradation increases geohazard risk and has already wielded considerable effects on the human and natural systems. Permafrost changes have also exerted a pronounced impact on the climate system through changes in permafrost carbon and land-atmosphere interactions. Future research should involve comparative studies of permafrost dynamics in both regions that integrate long-term observations, high-resolution satellite measurements, and advanced Earth System models, with emphasis on linkages between the two regions.
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| 2962. |
- Wang, Y. C., et al.
(författare)
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Analysis methodology of XCT results for testing ingress of substances in hardened cement paste: Explained with chloride immersion test
- 2019
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Ingår i: Construction and Building Materials. - : Elsevier BV. - 0950-0618. ; 229
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Tidskriftsartikel (refereegranskat)abstract
- X-ray computed tomography (XCT) can non-destructively detect microstructure of cement-based material. However, its raw results involve errors induced by the equipment and external factors. Once studying changes taken place in a sample, such as durability related studies, which need testing on a same sample at intervals, these errors will result in misleading conclusions. At the moment, in literature, no method focusing on effectively and reasonably eliminating or minimising these errors has not been observed. After testing and analysing ten series of XCT results for samples experiencing various types of exposures, authors established a rational data-processing method to minimise the influence of these errors on test results, and is introduced in this paper. To assist readers’ understanding, the method and relevant information are illustrated with a case of immersion of hardened cement pastes in NaCl solution. Obtained results prove that diffusion of substances in the hardened cement paste can be properly revealed with the data processing method introduced; trend and depth of microstructure change caused by the exposure can be determined; the immersion of samples in NaCl solution led to a gradual decrease in density and a further hydration of cement particles, which should be related to leaching of Calcium from the sample into immersion solution; once immersed in same NaCl solution, the change of microstructure in the 0.35 w/c was slower than that in the 0.5 w/c sample and the influence depth had an approximate linear relationship with square root of immersion duration.
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| 2963. |
- Wang, Y. J., et al.
(författare)
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Cyclic AMP in oocytes controls meiotic prophase I and primordial folliculogenesis in the perinatal mouse ovary
- 2015
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Ingår i: Development. - : The Company of Biologists. - 0950-1991 .- 1477-9129. ; 142:2, s. 343-351
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Tidskriftsartikel (refereegranskat)abstract
- In mammalian ovaries, a fixed population of primordial follicles forms during the perinatal stage and the oocytes contained within are arrested at the dictyate stage of meiotic prophase I. In the current study, we provide evidence that the level of cyclic AMP ( cAMP) in oocytes regulates oocyte meiotic prophase I and primordial folliculogenesis in the perinatal mouse ovary. Our results show that the early meiotic development of oocytes is closely correlated with increased levels of intra-oocyte cAMP. Inhibiting cAMP synthesis in fetal ovaries delayed oocyte meiotic progression and inhibited the disassembly and degradation of synaptonemal complex protein 1. In addition, inhibiting cAMP synthesis in in vitro cultured fetal ovaries prevented primordial follicle formation. Finally, using an in situ oocyte chromosome analysis approach, we found that the dictyate arrest of oocytes is essential for primordial follicle formation under physiological conditions. Taken together, these results suggest a role for cAMP in early meiotic development and primordial follicle formation in the mouse ovary.
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| 2964. |
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| 2965. |
- Wang, Y., et al.
(författare)
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The Impact of Different Degrees of Intraventricular Hemorrhage on Mortality and Neurological Outcomes in Very Preterm Infants: A Prospective Cohort Study
- 2022
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Ingår i: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveIntraventricular hemorrhage (IVH) is a common complication in preterm infants and is related to neurodevelopmental outcomes. Infants with severe IVH are at higher risk of adverse neurological outcomes and death, but the effect of low-grade IVH remains controversial. The purpose of this study was to evaluate the impact of different degrees of IVH on mortality and neurodevelopmental outcomes in very preterm infants. MethodsPreterm infants with a gestational age of ResultsA total of 1,079 preterm infants were included, and 380 (35.2%) infants had grade I-II IVH, 74 (6.9%) infants had grade III-IV IVH, and 625 (57.9%) infants did not have IVH. The mortality in the non-IVH, I-II IVH, and III-IV IVH groups was 20.1, 19.7, and 55.2%, respectively (p < 0.05), and the incidence of neurodevelopmental disabilities was 13.9, 16.1, and 43.3%, respectively (p < 0.05), at 18-24 months of corrected age. After adjusting for confounding factors, preterm infants with III-IV IVH had higher rates of cerebral palsy [26.7 vs. 2.4%, OR = 6.10, 95% CI (1.840-20.231), p = 0.003], disability [43.3 vs. 13.9%, OR = 2.49, 95% CI (1.059-5.873), p = 0.037], death [55.2 vs. 20.1%, OR = 3.84, 95% CI (2.090-7.067), p < 0.001], and disability + death [73.7 vs. 28.7%, OR = 4.77, 95% CI (2.518-9.021), p < 0.001] compared to those without IVH. However, the mortality and the incidence of neurodevelopmental disability in infants with I-II IVH were similar to those without IVH (p > 0.05). ConclusionsSevere IVH but not mild IVH increased the risk of mortality and neurodevelopmental disability in very preterm infants.
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| 2966. |
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| 2967. |
- Wang, Y, et al.
(författare)
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Wnt/beta-catenin signaling confers ferroptosis resistance by targeting GPX4 in gastric cancer
- 2022
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Ingår i: Cell death and differentiation. - : Springer Science and Business Media LLC. - 1476-5403 .- 1350-9047. ; 29:11, s. 2190-2202
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Tidskriftsartikel (refereegranskat)abstract
- The development of chemotherapy resistance is the most vital obstacle to clinical efficacy in gastric cancer (GC). The dysregulation of the Wnt/beta-catenin signaling pathway is critically associated with GC development and chemotherapy resistance. Ferroptosis is a form of regulated cell death, induced by an iron-dependent accumulation of lipid peroxides during chemotherapy. However, whether the Wnt/beta-catenin signaling directly controls resistance to cell death, remains unclear. Here, we show that the activation of the Wnt/beta-catenin signaling attenuates cellular lipid ROS production and subsequently inhibits ferroptosis in GC cells. The beta-catenin/TCF4 transcription complex directly binds to the promoter region of GPX4 and induces its expression, resulting in the suppression of ferroptotic cell death. Concordantly, TCF4 deficiency promotes cisplatin-induced ferroptosis in vitro and in vivo. Thus, we demonstrate that the aberrant activation of the Wnt/beta-catenin signaling confers ferroptosis resistance and suggests a potential therapeutic strategy to enhance chemo-sensitivity for advanced GC patients.
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| 2968. |
- Wang, Z. H., et al.
(författare)
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Investigation of combustion enhancement by ozone additive in CH(4)/air flames using direct laminar burning velocity measurements and kinetic simulations
- 2012
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Ingår i: Combustion and Flame. - : Elsevier BV. - 0010-2180. ; 159:1, s. 120-129
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Tidskriftsartikel (refereegranskat)abstract
- The effect of ozone additive on the enhancement of the burning velocity for premixed methane-air flames is investigated by both experimental measurements and kinetic simulations. Laminar burning velocities with and without O(3) were directly measured using the Heat Flux method. The O(3) molecules were introduced into the system by a dielectric-barrier-discharge ozone generator installed in the O(2) gas line, which provided prompt control of on/off of the O(3) feed into the system, enabling a precise comparison of the measured burning velocity with and without ozone additives. Noticeable burning velocity enhancement was observed at off-stoichiometric conditions rather than stoichiometric conditions. With 3730 ppm O(3) additive in the oxidizer, experimental data shows similar to 8% burning velocity increase in fuel-rich mixtures and similar to 3.5% burning velocity increase for the stoichiometric mixture. With 7000 ppm ozone additive in the oxidizer, maximum similar to 16% burning velocity increase was observed at fuel-lean conditions while similar to 9.0% was found at fuel-rich conditions. An O(3) kinetic mechanism involving 16 elementary reactions together with the GRI-Mech 3.0 was composed and validated through CHEMKIN calculations, which gives good predictions of the burning velocities with and without O(3) additives. Extra O radicals contributed by O(3) molecules in the pre-heat zone initiate and accelerate the chain-branching reactions and consequently increase the burning velocity. (C) 2011 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
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| 2969. |
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| 2970. |
- Weeland, CJ, et al.
(författare)
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The thalamus and its subnuclei-a gateway to obsessive-compulsive disorder
- 2022
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Ingår i: Translational psychiatry. - : Springer Science and Business Media LLC. - 2158-3188. ; 12:1, s. 70-
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Tidskriftsartikel (refereegranskat)abstract
- Larger thalamic volume has been found in children with obsessive-compulsive disorder (OCD) and children with clinical-level symptoms within the general population. Particular thalamic subregions may drive these differences. The ENIGMA-OCD working group conducted mega- and meta-analyses to study thalamic subregional volume in OCD across the lifespan. Structural T1-weighted brain magnetic resonance imaging (MRI) scans from 2649 OCD patients and 2774 healthy controls across 29 sites (50 datasets) were processed using the FreeSurfer built-in ThalamicNuclei pipeline to extract five thalamic subregions. Volume measures were harmonized for site effects using ComBat before running separate multiple linear regression models for children, adolescents, and adults to estimate volumetric group differences. All analyses were pre-registered (https://osf.io/73dvy) and adjusted for age, sex and intracranial volume. Unmedicated pediatric OCD patients (<12 years) had larger lateral (d = 0.46), pulvinar (d = 0.33), ventral (d = 0.35) and whole thalamus (d = 0.40) volumes at unadjusted p-values <0.05. Adolescent patients showed no volumetric differences. Adult OCD patients compared with controls had smaller volumes across all subregions (anterior, lateral, pulvinar, medial, and ventral) and smaller whole thalamic volume (d = −0.15 to −0.07) after multiple comparisons correction, mostly driven by medicated patients and associated with symptom severity. The anterior thalamus was also significantly smaller in patients after adjusting for thalamus size. Our results suggest that OCD-related thalamic volume differences are global and not driven by particular subregions and that the direction of effects are driven by both age and medication status.
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