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The onset of thermal convection in a rapidly rotating spherical shell is studied by linear stability analysis based on the fully compressible Navier–Stokes equations. Compressibility is quantified by the number of density scale heights
, which measures the intensity of density stratification of the motionless, polytropic base state. The nearly adiabatic flow with polytropic index
is considered, where
is the adiabatic polytropic index. By investigating the stability of the base state with respect to the disturbance of specified wavenumber, the instability process is found to be sensitive to the Prandtl number
. For large
, the quasi-geostrophic columnar mode loses stability first; while for relatively small
a new quasi-geostrophic compressible mode is identified, which becomes unstable first under strong density stratification. The inertial mode can also occur first for relatively small
and a certain intensity of density stratification in the parameter range considered. Although the Rayleigh numbers
for the onsets of the quasi-geostrophic compressible mode and columnar mode are different by several orders of magnitude, we find that they follow very similar scaling laws with the Taylor number. The critical
for convection onset is found to be always positive, in contrast with previous results based on the widely used anelastic model that convection can occur at negative
. By evaluating the relative magnitude of the time derivative of density perturbation in the continuity equation, we show that the anelastic approximation in the present system cannot be applied in the small-
Schizophrenia is a complex mental disorder with high heritability and polygenic inheritance. Multimodal neuroimaging studies have also indicated that abnormalities of brain structure and function are a plausible neurobiological characterisation of schizophrenia. However, the polygenic effects of schizophrenia on these imaging endophenotypes have not yet been fully elucidated.
To investigate the effects of polygenic risk for schizophrenia on the brain grey matter volume and functional connectivity, which are disrupted in schizophrenia.
Genomic and neuroimaging data from a large sample of Han Chinese patients with schizophrenia (N = 509) and healthy controls (N = 502) were included in this study. We examined grey matter volume and functional connectivity via structural and functional magnetic resonance imaging, respectively. Using the data from a recent meta-analysis of a genome-wide association study that comprised a large number of Chinese people, we calculated a polygenic risk score (PGRS) for each participant.
The imaging genetic analysis revealed that the individual PGRS showed a significantly negative correlation with the hippocampal grey matter volume and hippocampus–medial prefrontal cortex functional connectivity, both of which were lower in the people with schizophrenia than in the controls. We also found that the observed neuroimaging measures showed weak but similar changes in unaffected first-degree relatives of patients with schizophrenia.
These findings suggested that genetically influenced brain grey matter volume and functional connectivity may provide important clues for understanding the pathological mechanisms of schizophrenia and for the early diagnosis of schizophrenia.
Objective: Deficits in the semantic learning strategy were observed in subjects with amnestic mild cognitive impairment (aMCI) in our previous study. In the present study, we explored the contributions of executive function and brain structure changes to the decline in the semantic learning strategy in aMCI. Methods: A neuropsychological battery was used to test memory and executive function in 96 aMCI subjects and 90 age- and gender-matched healthy controls (HCs). The semantic clustering ratio on the verbal learning test was calculated to evaluate learning strategy. Medial temporal lobe atrophy (MTA) and white matter hyperintensities (WMH) were measured on MRI with the MTA and Fazekas visual rating scales, respectively. Results: Compared to HCs, aMCI subjects had poorer performance in terms of memory, executive function, and the semantic clustering ratio (P < .001). In aMCI subjects, no significant correlation between learning strategy and executive function was observed. aMCI subjects with obvious MTA demonstrated a lower semantic clustering ratio than those without MTA (P < .001). There was no significant difference in the learning strategies between subjects with high-grade WMH and subjects with low-grade WMH. Conclusion: aMCI subjects showed obvious impairment in the semantic learning strategy, which was attributable to MTA but independent of executive dysfunction and subcortical WMH. These findings need to be further validated in large cohorts with biomarkers identified using volumetric brain measurements. (JINS, 2019, 25, 706–717)
There is limited experience about transcatheter closure of doubly committed subarterial ventricular septal defects with Amplatzer ductal occluder.
Between March, 2015 and July, 2017, a total of 22 patients with doubly committed subarterial ventricular septal defects received transcatheter closure using Amplatzer ductal occluder and underwent clinical follow-up for at least 6 months.
Device implantation was finally successful in 21 (95.4%) patients despite failed occlusion in one patient and intra-procedural replacement of unsuitable occluders in four (19.0%) patients. In mean 12.3 months of follow-up, there were no major complications (death, aortic valve or sinus rupture, device dislocation or embolisation, grade 2 new-onset aortic regurgitation, etc.), resulting in clinical occlusion success of 95.4%. Mechanical haemolysis occurred in one patient and resolved with medication. Residual shunt was observed in 11 (52.4%) patients (9 mild, 2 moderate-severe) post-procedurally, 14 (66.7%) patients (12 mild, 2 moderate-severe) in hospital stay, and 2 (9.5%) patients (2 mild, 0 moderate-severe) at the last follow-up. Device-induced new-onset aortic regurgitation was found in nine (42.8%) patients (9 mild, 0 moderate-severe) post-procedurally and in hospital stay, which was resolved in two (9.5%) patients and unchanged in seven (33.3%) patients at the last follow-up. Another four (19.0%) patients newly developed mild aortic regurgitation during follow-up.
Transcatheter closure of doubly committed subarterial ventricular septal defects with Amplatzer ductal occluder is technically feasible in the selected patients. However, further study is needed to confirm its long-term clinical outcomes.
CrFeNiTix (x = 0.2, 0.3, 0.4, 0.5, and 0.6 molar ratio) compositionally complex alloys were fabricated by vacuum arc melting to investigate the microstructure, hardness, and compressive properties. The results revealed that CrFeNiTix alloys consisted of the principal face-centered cubic (FCC) phase and body-centered cubic (BCC) solid solution, with an amount of (Ni, Ti)-rich hexagonal close-packed phase. CrFeNiTix alloys exhibited the typical dendrite. Ti0.2 and Ti0.3 alloys were composed of FCC and BCC solid solutions in the dendrite, as well as ε (Ni3Ti) and R (Ni2.67Ti1.33) phases in the inter-dendrite, simultaneously. For Ti0.4, Ti0.5, and Ti0.6 alloys, (Fe, Cr)-rich solid solution separated out and ε phase transformed into R phase gradually. Meanwhile, TEM analysis indicated that Ti0.4 alloy matrix consisted of the principal FCC phase containing (Ni, Ti)-rich intragranular nanoprecipitates. The hardness values of CrFeNiTix alloys were increased with the addition of Ti content and the high compressive strength of CrFeNiTix alloys was maintained, which was attributed to the solid solution strengthening and precipitation hardening.
As rarely large flake graphite (9 mesh) was recently exploited in China, it was innovatively developed as the raw material to prepare a novel wound dressing based on large expanded graphite (EG) in this work. The EG worms were prepared in an easy oxidative intercalation and thermal expansion method. Afterward, chitosan was grafted onto the surface of EG by chemical modification, forming CS-EG worms. CS-EG sponge dressings were then obtained by pressing a number of CS-EG worms together by external force. Due to the porous structure and large specific surface area, the produced CS-EG sponges exhibited outstanding adsorption capacity for wound exudate. They could also promote blood coagulation by adsorbing the blood cells and proteins quickly and effectively, showing excellent hemostatic performance. The eminent performances and the simple preparation process ensure the great application potential of CS-EG as a dressing material. This is also the first time to report the application of the traditional carbon material, EG, to act as a dressing material after chemical modification.
Paroxysmal atrial fibrillation (PAF) represents a significant economic burden to the healthcare system. Catheter ablation is a commonly adopted treatments for PAF, and cryoballoon ablation (CBA) has been recently proven to be as effective as radiofrequency ablation (RFA). This study aims to evaluate the cost-effectiveness of CBA versus RFA in patients with drug-refractory PAF in China.
A Markov model was developed to study the effects and the costs of CBA versus RFA. Cost and probability inputs data were obtained mainly from a real-world study of 85 CBA and 284 RFA patients treated in a tertiary hospital between July 2014 and July 2016. Propensity score matching was used to overcome retrospective bias, resulting in including 75 patients in each group. Input data gaps were closed with literature review and advisory board. A simulation was carried out for 14 cycles/years, and a discount rate of 3 percent was used. Then, a probabilistic sensitivity analysis was carried out with Monte Carlo approach.
In the base case scenario, the cumulative costs incurred by the CBA and RFA groups were CNY 132,222 (USD 20,767) and CNY 147,304 (USD 23,136), respectively. Over the 14-year period, the quality-adjusted life years (QALYs) gained by the CBA group was 7.85 versus 7.71 in the RFA group. The incremental cost-effectiveness ratio for CBA versus RFA was thus CNY 107,729 (USD 16,920)/QALY. Model results were most sensitive to the cost incurred during the first hospitalization, recurrence rate, and relative utility weights. The probability of CBA being cost-effective for willingness to pay thresholds of per capita GDP in China was estimated to be 99 percent.
Compared with RFA, CBA is a cost-saving treatment providing increased QALYs. It represents good value for money for patients with drug-refractory PAF in China. However, further evidence needs to be generated from larger-scale studies in China.
The Hudesheng mafic–ultramafic intrusions are located in the Oulongbuluke Block, north of the Qaidam Block in Qinghai Province, NW China. We carried out a detailed study of the intrusions, including field observations, petrology, zircon U–Pb geochronology, Lu–Hf isotopes, bulk-rock major- and trace-element geochemistry, and mineral compositions, to provide a better understanding of their properties and the regional tectonic evolution. Zircon U–Pb dating on gabbro and pyroxenite samples yielded ages of 465 and 455 Ma, respectively. Geochemical data, in conjunction with the field observations and petrological features, suggest that the complex is Alaskan-type and the magma was derived from a depleted mantle source that was hydrous picritic basalt in composition and influenced by crustal contamination and slab-derived fluid metasomatism. Based on all the chronological, petrological, mineralogical and geochemical and regional geological data, we conclude that the palaeo-ocean closed diachronously from west to east between the Qaidam and Oulongbuluke blocks, and that the ocean in the east of the North Qaidam region closed after ∼455 Ma.
Memory and Agency in Ancient China offers a novel perspective on China's material culture. The volume explores the complex 'life histories' of selected objects, whose trajectories as ginle objects ('biographies') and object types ('lineages') cut across both temporal and physical space. The essays, written by a team of international scholars, analyse the objects in an effort to understand how they were shaped by the constraints of their social, political and aesthetic contexts, just as they were also guided by individual preference and capricious memory. They also demonstrate how objects were capable of effecting change. Ranging chronologically from the Neolithic to the present, and spatially from northern to southern mainland China and Taiwan, this book highlights the varied approaches that archaeologists and art historians use when attempting to reconstruct object trajectories. It also showcases the challenges they face, particularly with the unearthing of objects from archaeological contexts that, paradoxically, come to represent the earliest known point of their 'post-recovery lives'.
We hypothesize that the tumor necrosis factor-α (TNF-α) may play a role in disturbing the effect of selective serotonin reuptake inhibitor (SSRI) on the striatal connectivity in patients with major depressive disorder (MDD).
We performed a longitudinal observation by combining resting-state functional magnetic resonance imaging (rs-fMRI) and biochemical analyses to identify the abnormal striatal connectivity in MDD patients, and to evaluate the effect of TNF-α level on these abnormal connectivities during SSRI treatment. Eighty-five rs-fMRI scans were collected from 25 MDD patients and 35 healthy controls, and the scans were repeated for all the patients before and after a 6-week SSRI treatment. Whole-brain voxel-wise functional connectivity (FC) was calculated by correlating the rs-fMRI time courses between each voxel and the striatal seeds (i.e. spherical regions placed at the striatums). The level of TNF-α in serum was evaluated by Milliplex assay. Factorial analysis was performed to assess the interaction effects of ‘TNF-α × treatment’ in the regions with between-group FC difference.
Compared with controls, MDD patients showed significantly higher striatal FC in the medial prefrontal cortex (MPFC) and bilateral middle/superior temporal cortices before SSRI treatment (p < 0.001, uncorrected). Moreover, a significant interaction effect of ‘TNF-α × treatment’ was found in MPFC-striatum FC in MDD patients (p = 0.002), and the significance remained after adjusted for age, gender, head motion, and episode of disease.
These findings provide evidence that treatment-related brain connectivity change is dependent on the TNF-α level in MDD patients, and the MPFC-striatum connectivities possibly serve as an important target in the brain.
Heavy metal contamination in the paddy soils of China is a serious concern because of its health risk through transfer in food chains. A field experiment was conducted in 2014–2015 to investigate the long-term effects of different biochar amendments on cadmium (Cd) and arsenic (As) immobilisation in a contaminated paddy field in southern China. Two types of biochar, a rice-straw-derived biochar (RB) and a coconut-by-product-derived biochar (CB), were amended separately to determine their impacts on rice yield and their efficacy in reducing Cd and As in rice. The two-year field experiment showed that biochar amendments significantly improved the rice yields and that CB is superior to RB, especially in the first growth season. Using a large amount of biochar amendment (22.5tha–1) significantly increased soil pH and total organic carbon, and concomitantly decreased the Cd content in rice grains over the four growth seasons, regardless of biochar type and application rate. Arsenic levels in rice were similar to the control, and results from this study suggest that there was a sustainable effect of biochar on Cd sequestration in soil and reduction of Cd accumulation in rice for at least two years. Biochar amendment in soil could be considered as a sustainable, reliable and cost-effective option to remediate heavy metal contamination in paddy fields for long periods.
The aim of this study was to investigate the in vivo degradation mechanism and the mechanical properties of poly(lactide-co-glycolide)/beta-tricalcium phosphate (PLGA/β-TCP) composite anchors. Anchors composed of PLGA and β-TCP were implanted in the dorsal subcutaneous tissue of beagle dogs for 6, 12, 16, and 26 weeks. The degradation of the materials was evaluated by measuring the changes in thermal behavior, crystallinity, and mechanical properties. Scanning electron microscope (SEM) was used to observe the surface and longitudinal section of the material. The evaluation of mechanical strength retention and degradation properties suggest that the addition of β-TCP particles efficiently enhances their mechanical properties and thermal characteristics and delays their degradation rate. By analyzing the results of SEM, X-ray diffraction, and differential scanning calorimetry, we can infer that after 12 weeks, the connection between β-TCP and PLGA becomes less compact, which accelerates the decline of mechanical strength.