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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-
Existing data on folate status and hepatocellular carcinoma (HCC) prognosis are scarce. We prospectively examined whether serum folate concentrations at diagnosis were associated with liver cancer-specific survival (LCSS) and overall survival (OS) among 982 patients with newly diagnosed, previously untreated HCC, who were enrolled in the Guangdong Liver Cancer Cohort (GLCC) study between September 2013 and February 2017. Serum folate concentrations were measured using chemiluminescent microparticle immunoassay. Cox proportional hazards models were performed to estimate hazard ratios (HR) and 95 % CI by sex-specific quartile of serum folate. Compared with patients in the third quartile of serum folate, patients in the lowest quartile had significantly inferior LCSS (HR = 1·48; 95 % CI 1·05, 2·09) and OS (HR = 1·43; 95 % CI 1·03, 1·99) after adjustment for non-clinical and clinical prognostic factors. The associations were not significantly modified by sex, age at diagnosis, alcohol drinking status and Barcelona Clinic Liver Cancer (BCLC) stage. However, there were statistically significant interactions on both multiplicative and additive scale between serum folate and C-reactive protein (CRP) levels or smoking status and the associations of lower serum folate with worse LCSS and OS were only evident among patients with CRP > 3·0 mg/l or current smokers. An inverse association with LCSS were also observed among patients with liver damage score ≥3. These results suggest that lower serum folate concentrations at diagnosis are independently associated with worse HCC survival, most prominently among patients with systemic inflammation and current smokers. A future trial of folate supplementation seems to be promising in HCC patients with lower folate status.
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.
Paediatric Mycoplasma pneumoniae pneumonia (MPP) is a major cause of community-acquired pneumonia in China. Data on epidemiology of paediatric MPP from China are little known. This study retrospectively collected data from June 2006 to June 2016 in Beijing Children's Hospital, Capital Medical University of North China and aims to explore the epidemiological features of paediatric MPP and severe MPP (SMPP) in North China during the past 10 years. A total of 27 498 paediatric patients with pneumonia were enrolled. Among them, 37.5% of paediatric patients had MPP. In this area, an epidemic took place every 2–3 years at the peak, and the positive rate of MPP increased during these peak years over time. The peak age of MPP was between the ages of 6 and 10 years, accounting for 75.2%, significantly more compared with other age groups (χ2 = 1384.1, P < 0.0001). The epidemics peaked in September, October and November (χ2 = 904.9, P < 0.0001). Additionally, 13.0% of MPP paediatric patients were SMPP, but over time, the rate of SMPP increased, reaching 42.6% in 2016. The mean age of paediatric patients with SMPP (6.7 ± 3.0 years old) was younger than that of patients with non-SMPP (7.4 ± 3.2 years old) (t = 3.60, P = 0.0001). The prevalence of MPP and SMPP is common in China, especially in children from 6 to 10 years old. Paediatric patients with SMPP tend to be younger than those with non-SMPP. MPP outbreaks occur every 2–3 years in North China. September, October and November are the peak months, unlike in South China. Understanding the epidemiological characteristics of paediatric MPP can contribute to timely treatment and diagnosis, and may improve the prognosis of children with SMPP.
The antennal sensilla of female Quadrastichus mendeli Kim & La Salle (Hymenoptera: Eulophidae: Tetrastichinae) were observed with scanning and transmission electron microscopy in this study. The antenna of Q. mendeli was geniculate, and the flagellum was composed of seven subsegments. Six distinct types of sensory receptors were observed, including sensilla basiconic capitate peg, sensilla böhm, sensilla chaetica, sensilla campaniformia, sensilla placodea and sensilla trichodea. Sensilla basiconic capitate pegs were found on the flagellomeres, and Böhm sensilla were found on the basal part of scape and the pedicel. Two morphological subtypes of sensilla chaetica were found on the antennae, and sensilla campaniformia were only found on the pedicel. Sensilla placodea were divided into two morphological subtypes that were found on the flagellomeres. Sensilla trichodea were found on the 2nd–6th flagellomere. By comparison to existing antennal sensilla, it was found that sensilla basiconic capitate peg, sensilla chaetica, sensilla placodea and sensilla trichodea were the most common sensilla of the parasitoids of Eulophidae. The external and internal morphology, types, number, distribution, length, and width of these sensilla were described, and their possible functions are discussed in conjunction with the host-detection behavior. Future studies on the host location mechanisms in Q. mendeli will be facilitated by these observations.
Monosized spherical Cu–20% Sn (wt%) alloy particles with diameter ranging from 70.6 to 334.0 μm were prepared by the pulsated orifice ejection method (termed “POEM”). Fully dense without pores and bulk inclusions, the cross-sectional micrographs of the spherical alloy particles indicate an even distribution of Cu and Sn. These spherical Cu–Sn alloy particles exhibit a good spherical shape and a narrow size distribution, suggesting that the liquid Cu–Sn alloy can completely break the balance between the surface tension and the liquid static pressure in the crucible micropores and accurately control the volume of the droplets. Furthermore, the cooling rate of spherical Cu–20% Sn alloy particles is estimated by a Newton’s cooling model. The cooling rate of the Cu–20% Sn alloy particle decreases gradually with the particle diameter increasing. Smaller particles have higher cooling rates and when the particle diameter is less than 70 μm, the cooling rate of particles can reach more than 3.3 × 104 K/s. The secondary dendrite arm spacing has strong dependence on particle diameter which increases gradually with the increase of particle diameter. The results demonstrate that POEM is an effective route for fabrication of high-quality monosized Cu–20% Sn alloy particles.
The influences of non-Oberbeck–Boussinesq (NOB) effects on flow instabilities and bifurcation characteristics of Rayleigh–Bénard convection are examined. The working fluid is air with reference Prandtl number
and contained in two-dimensional rigid cavities of finite aspect ratios. The fluid flow is governed by the low-Mach-number equations, accounting for the NOB effects due to large temperature difference involving flow compressibility and variations of fluid viscosity and thermal conductivity with temperature. The intensity of NOB effects is measured by the dimensionless temperature differential
. Linear stability analysis of the thermal conduction state is performed. An
scaling of the leading-order corrections of critical Rayleigh number
and disturbance growth rate
due to NOB effects is identified, which is a consequence of an intrinsic symmetry of the system. The influences of weak NOB effects on flow instabilities are further studied by perturbation expansion of linear stability equations with regard to
, and then the influence of aspect ratio
is investigated in detail. NOB effects are found to enhance (weaken) flow stability in large (narrow) cavities. Detailed contributions of compressibility, viscosity and buoyancy actions on disturbance kinetic energy growth are identified quantitatively by energy analysis. Besides, a weakly nonlinear theory is developed based on centre-manifold reduction to investigate the NOB influences on bifurcation characteristics near convection onset, and amplitude equations are constructed for both codimension-one and -two cases. Rich bifurcation regimes are observed based on amplitude equations and also confirmed by direct numerical simulation. Weakly nonlinear analysis is useful for organizing and understanding these simulation results.
In traditional antenna design, metal components are not placed in the central part of the antenna as they change the characteristics of near field radiation. However, we show that placing a metal ring in the centre of the strip lines, which connect the ends of folded high-frequency dipoles, does not damage the performance of the feed. Instead it significantly improves the voltage standing wave ratio of the feed whilst other performance indicators are not compromised. Thus, our findings show an excellent way of improving the wide band feed. Based on this foundation, a new circularly polarised feed for operation between 0.4 to 2 GHz is introduced for the Chinese Spectral Radioheliograph in this paper. The issue of a feed impedance matching network is investigated. By optimising the impedance matching, the performance of the feed is enhanced with respect to the previous realisations of the Eleven feed. The simulation and experimental results show that the gain of the feed is about 10 dBi, and the VSWR is less than 2:1. In addition, the feed has a low axial ratio, fixed phase centre location, and constant beam width in the range of 0.4 to 2 GHz.
The ground state properties of Fe3−xCrxO4 (x = 0–3) compounds were studied using first principles calculation. Stress–strain methods were used to evaluate elastic constants of these compounds. These compounds are mechanically stable structures, because they satisfy the mechanical stability criteria. The mechanical moduli were estimated using the Voigt–Reuss–Hill approximation. The calculated bulk moduli of Fe3O4, Fe2CrO4, FeCr2O4, and Cr3O4 are 190.9 GPa, 135.5 GPa, 180.1 GPa, and 235.6 GPa, respectively. Both of anisotropic indexes and 3-D surface contour were used to illustrate the elastic anisotropy. Debye temperature and anisotropy of acoustic velocity of Fe3−xCrxO4 compounds were also investigated. The maximum Debye temperature is attributing to Cr3O4 with 507.6 K among Fe3−xCrxO4 compounds. The minimum thermal conductivity of Fe3−xCrxO4 compounds was estimated by both Clarke's model and Cahill's model. Moreover, 3-D surface contour of the anisotropic thermal conductivity of Fe3−xCrxO4 compounds was obtained based on the Clarke's model and anisotropic Young's modulus.
A magnesium–lithium (Mg–Li) hybrid battery consists of an Mg metal anode, a Li+ intercalation cathode, and a dual-salt electrolyte with both Mg2+ and Li+ ions. The demonstration of this technology has appeared in literature for few years and great advances have been achieved in terms of electrolytes, various Li cathodes, and cell architectures. Despite excellent battery performances including long cycle life, fast charge/discharge rate, and high Coulombic efficiency, the overall research of Mg–Li hybrid battery technology is still in its early stage, and also raised some debates on its practical applications. In this regard, we focus on a comprehensive overview of Mg–Li hybrid battery technologies developed in recent years. Detailed discussion of Mg–Li hybrid operating mechanism based on experimental results from literature helps to identify the current status and technical challenges for further improving the performance of Mg–Li hybrid batteries. Finally, a perspective for Mg–Li hybrid battery technologies is presented to address strategic approaches for existing technical barriers that need to be overcome in future research direction.
To retrospectively analyze the rescue and treatment of pediatric patients by the Chinese Red Cross medical team during the Nepal earthquake relief.
The medical team set up a field hospital; the pediatric clinic consisted of 1 pediatrician and several nurses. Children younger than 18 years old were placed in the pediatric clinic for injury examination and treatment.
During the 7-day period of medical assistance (the second to third week after the earthquake), a total of 108 pediatric patients were diagnosed and treated, accounting for 2.8% of the total patients. The earthquake-related injuries mainly required surgical dressing and debridement. No severe limb fractures or traumatic brain injuries were found. Infection of the respiratory tract, the gastrointestinal tract, and the skin were the most common ailments, accounting for 42.3%, 18.5%, and 16.7%, respectively, of the total treated patients.
Two to 3 weeks after the earthquake, the admitted pediatric patients mainly displayed respiratory and gastrointestinal infections. When developing a rescue plan and arranging medical resources, we should consider the necessity of treating non–disaster-related conditions. (Disaster Med Public Health Preparedness. 2016;page 1 of 4)
The co-doped ZnB2O4:Eu3+, Tb3+ phosphor was prepared by a thermal conversion method using Zn[B3O3(OH)5]·H2O:Eu3+, Tb3+ as the precursor, which was characterized by energy dispersive x-ray spectrometer, x-ray powder diffraction, infrared, scanning electron microscopy, and photoluminescence. The effects of doped concentration, calcining temperature, and calcining time of precursor on the luminescence property of ZnB2O4: Eu3+, Tb3+ phosphor were investigated. The results showed that the ZnB2O4: Eu3+, Tb3+ phosphor with maximum luminescent intensity was obtained by calcining the precursor at 900 °C for 6 h. It is found that the ZnB2O4: Eu3+, Tb3+ phosphor prepared by this method exhibits much stronger emission intensity than that synthesized by conventional high temperature solid-state method. Meanwhile, ZnB2O4: Eu3+, Tb3+ also has stronger emission intensity and higher red to orange ratio than those of ZnB2O4: Eu3+.
Introduction: The mortality of Parkinson’s disease (PD) and its associated risk factors among clinically definite PD patients in China has been rarely investigated. Our study aimed to identify the mortality rates and predictors of death in PD patients in China. Methods: 157 consecutive, clinically definite PD patients from the urban area of Shanghai were recruited from a central hospital based movement disorder clinic in 2006. All patients were regularly followed up at the clinic until December 31, 2011, or death. Mortality and associations with baseline demographics, health and medical factors were then determined within the cohort. Results: After 5 years, 11(7%) patients had died. The standardised mortality ratio was 0.62 (95% CI 0.32 to 1.07, P=0.104). The main causes of death were pneumonia (54.5%, 6/11) and digestive disorders (18.2%, 2/11), respectively. Age at onset, independent living, the mini mental state examination score, the Parkinson’s disease sleep scale score and the Epworth sleepiness scale score at baseline were statistically significantly different between the survival group and the deceased group (P<0.05). Across all participants, risk factors for death included low mini mental state examination score, and high Epworth sleepiness scale score according to a binary variable logistic regression analysis. Conclusions: This study confirms the similar survival of patients with PD to the control population up to a follow-up of 5 years. Interventions tailored to potential risk factors associated with death may offer further benefits.
Analyses of morphological, anatomical, chemical and DNA sequences led to the recognition of ten species of Anzia in the Hengduan Mountains, which harbour all species known from China, including A. pseudocolpota sp. nov. and A. hypomelaena comb. & stat. nov. Furthermore, populations similar to A. hypoleucoides but with narrow lobes and a yellow-orange pigmented medulla may be a phylogenetically distinct species tentatively recognized as A. aff. hypoleucoides. The species are primarily distinguished by the presence or absence of a central axis, the colour and shape of the spongy cushion and the nature of the secondary compounds. A key to all known species of Anzia from China is presented.
Mycotoxins, such as aflatoxin (AF), fumonisin B1, zearalenone (ZEA), and deoxynivalenol (DON), are commonly found in many food commodities. Mycotoxins have been shown to increase DNA methylation levels in a human intestinal cell line. We previously showed that the developmental competence of oocytes was affected in mice that had been fed a mycotoxin-containing diet. In this study, we explored possible mechanisms of low mouse oocyte developmental competence after mycotoxin treatment in an epigenetic modification perspective. Mycotoxin-contaminated maize (DON at 3,875 μg/kg, ZEA at 1,897 μg/kg, and AF at 806 μg/kg) was included in diets at three different doses (mass percentage: 0, 15, and 30%) and fed to mice for 4 weeks. The fluorescence intensity analysis showed that the general DNA methylation levels increased in oocytes from high dose mycotoxin-fed mice. Mouse oocyte histone methylation was also altered. H3K9me3 and H4K20me3 level increased in oocytes from mycotoxin-fed mice, whereas H3K27me3 and H4K20me2 level decreased in oocytes from mycotoxin-fed mice. Thus, our results indicate that naturally occurring mycotoxins have effects on epigenetic modifications in mouse oocytes, which may be one of the reasons for reduced oocyte developmental competence.
In 2008 January the 24th Chinese expedition team successfully deployed the Chinese Small Telescope ARray (CSTAR) to Dome A, the highest point on the Antarctic plateau. CSTAR consists of four 14.5cm optical telescopes, each with a different filter (g, r, i and open) and has a 4.5°×4.5° field of view (FOV). Based on the CSTAR data, initial statistics of astronomical observational site quality and light curves of variable objects were obtained. To reach higher photometric quality, we are continuing to work to overcome the effects of uneven cirrus cloud cirrus, optical “ghosts” and intra-pixel sensitivity. The snow surface stability is also tested for further astronomical observational instrument and for glaciology studies.
Objective: Functional imaging studies of post-traumatic stress disorder (PTSD) have shown an increased activation of posterior cingulate gyrus (PCG) of the brain. The aim of this study was to explore white matter integrity of PCG in PTSD subjects.
Methods: White matter integrity, as determined from fractional anisotropy (FA) value using diffusion tensor imaging, was assessed for PCG in subjects with and without PTSD from a severe mine accident. All subjects were also measured by the PTSD Checklist Civilian Version (PCL-C), the State-Trait Anxiety Inventory (STAI), the logical memory subtest and the visual reproduction subtest of the Wechsler Memory Scale-Revised in China. Sixteen PTSD subjects (8 subjects in each group) in the longitudinal study and 13 PTSD subjects as well as 14 non-PTSD controls in the cross-sectional case–control study were respectively recruited.
Results: In the longitudinal study, subjects with PTSD showed increased FA values in left PCG during the follow-up scan. In the cross-sectional study, FA values in bilateral PCG in PTSD subjects were higher than controls. Within the PTSD group (n = 13), FA values in the left PCG correlated positively with logical memory and negatively with PCL-C intrusion and STAI-trait (STAI-t) subscores. FA values in right PCG correlated negatively with STAI-t and STAI-state subscores.
Conclusion: These findings suggest that alterations of white matter integrity in PCG link to mnemonic and affective processing in PTSD over the long-term follow-up period.
The strategies of repair of tetralogy of Fallot change with the age of patients. In children older than 4 years and adults, the optimal strategy may be to use different method of reconstruction of the right ventricular outflow tract from those followed in younger children, so as to avoid, or reduce, the pulmonary insufficiency that is increasingly known to compromise right ventricular function.
From April, 2001, through May, 2008, we undertook complete repair in 312 patients, 180 male and 132 female, with a mean age of 11.3 years ±0.4 years, and a range from 4 to 48 years, with typical clinical and morphological features of tetralogy of Fallot, including 42 patients with the ventriculo-arterial connection of double outlet right ventricle. The operation was performed under moderate hypothermia using blood cardioplegia. The ventricular septal defect was closed with a Dacron patch. When it was considered necessary to resect the musculature within the right ventricular outflow tract, or perform pulmonary valvotomy, we sought to preserve the function of the pulmonary valve by protecting as far as possible the native leaflets, or creating a folded monocusp of autologous pericardium.
The repair was achieved completely through right atrium in 192, through the right ventricular outflow tract in 83, and through the right atrium, the outflow tract, and the pulmonary trunk in 36 patients. A transjunctional patch was inserted in 169 patients, non-valved in all but 9. There were no differences regarding the periods of aortic cross-clamping or cardiopulmonary bypass. Of the patients, 5 died (1.6%), with no influence noted for the transjunctional patch. Of those having a non-valved patch inserted, three-tenths had pulmonary regurgitation of various degree, while those having a valved patch had minimal pulmonary insufficiency and good right ventricular function postoperatively, this being maintained after follow-up of 8 to 24-months.
Based on our experience, we suggest that the current strategy of repair of tetralogy of Fallot in older children and adults should be based on minimizing the insertion of transjunctional patches, this being indicated only in those with very small ventriculo-pulmonary junctions. If such a patch is necessary, then steps should be taken to preserve the function of the pulmonary valve.
Reports arose from major Chinese wheat production regions that flixweed was not controlled by tribenuron after the herbicide was continuously used for several years. Flixweed seeds were collected from wheat fields that had been treated with tribenuron repeatedly over 3 to 15 yr or from road sides and remote hills that had never received tribenuron in Jiangsu, Hebei, Shanxi, Sichuan, Shandong, Shaanxi, and Henan provinces, and Tianjin and Beijing metropolises in China. The response of various biotypes to tribenuron was determined by whole plant experiments in the greenhouse. The experiments demonstrated that 11 of 32 flixweed biotypes were susceptible to tribenuron. The remaining 21 biotypes expressed moderate to high levels of tribenuron resistance with resistance indices ranging from 4 to > 1,500. DNA sequence analysis of acetolactate synthase (ALS) genes of selected biotypes 6, 7, 27, and 29 revealed a point mutation at position 197 of the ALS gene, as numbered relative to the protein sequence of Arabidopsis, where proline was substituted by leucine in biotype 7 and by threonine in biotype 29. These mutations are known to confer resistance to ALS-inhibiting herbicides and are responsible for the high resistance of these biotypes to tribenuron. The results also indicate that tribenuron resistance in flixweed is widespread in China and management programs to control these resistant populations are warranted.