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Spectral observations with high temporal and frequency resolution are of great significance for studying the fine structures of solar radio bursts. In addition, it is helpful to understand the physical processes of solar eruptions. In this paper, we present the design of a system to observe solar radio bursts with high temporal and frequency resolutions at frequencies of 25–110 MHz. To reduce the impact of analog devices and improve the system flexibility, we employ various digital signal processing methods to achieve the function of analog devices, such as polarisation synthesis and beamforming. The resourceful field programmable gate array is used to process radio signals. The system has a frequency resolution of
30 kHz and a temporal resolution of up to 0.2 ms. The left/right circular polarisation signals can be simultaneously observed. At present, the system has been installed at Chashan Solar Observatory operated by the Institute of Space Science, Shandong University. The system is running well, multiple bursts have been observed, and relevant data have been obtained.
We consider the situation of a misalignment between the global temperature gradient and gravity in thermal convection. In such a case an effective horizontal buoyancy arises that will significantly influence the transport properties of heat, mass and momentum. It may also change the flow morphology in turbulent convection. In this paper, we present an experimental and numerical study, using Rayleigh–Bénard convection as a platform, to explore systematically the effect of horizontal buoyancy on heat transport in turbulent thermal convection. Experimentally, a condition of increasing horizontal Rayleigh number ($Ra_H$, which is the non-dimensional horizontal thermal driving strength) under fixed vertical Rayleigh number ($Ra_V$, the non-dimensional vertical driving strength) is achieved by tilting the convection cell and simultaneously increasing the imposed temperature difference. We find that, with increasing horizontal to vertical buoyancy ratio ($\varLambda = Ra_H/Ra_V$), the overall heat transport manifests a monotonic increase in vertical heat transport ($Nu_V$) as well as a monotonic increase in its horizontal component ($Nu_H$). However, the horizontal Nusselt number is found to be approximately one order of magnitude smaller than the vertical Nusselt for the parameter range explored. We also show that the non-zero $Nu_H$ results from the broken azimuthal symmetry of the system induced by the horizontal buoyancy. We find that the enhancement of vertical heat transport comes from the increased shear generated by the horizontal buoyancy at the boundary layer. The effect of Prandtl number ($Pr$) is also studied numerically. Finally, we extend the Grossmann–Lohse theory to the case with an effective horizontal buoyancy, the result of which is successful in predicting $Nu_V(Ra_V,\varLambda ,Pr)$.
The structural changes recent-onset posttraumatic stress disorder (PTSD) subjects were rarely investigated. This study was to compare temporal and causal relationships of structural changes in recent-onset PTSD with trauma-exposed control (TEC) subjects and non-TEC subjects.
T1-weighted magnetic resonance images of 27 PTSD, 33 TEC and 30 age- and sex-matched healthy control (HC) subjects were studied. The causal network of structural covariance was used to evaluate the causal relationships of structural changes in PTSD patients.
Volumes of bilateral hippocampal and left lingual gyrus were significantly smaller in PTSD patients and TEC subjects than HC subjects. As symptom scores increase, reduction in gray matter volume began in the hippocampus and progressed to the frontal lobe, then to the temporal and occipital cortices (p < 0.05, false discovery rate corrected). The hippocampus might be the primary hub of the directional network and demonstrated positive causal effects on the frontal, temporal and occipital regions (p < 0.05, false discovery rate corrected). The frontal regions, which were identified to be transitional points, projected causal effects to the occipital lobe and temporal regions and received causal effects from the hippocampus (p < 0.05, false discovery rate corrected).
The results offer evidence of localized abnormalities in the bilateral hippocampus and remote abnormalities in multiple temporal and frontal regions in typhoon-exposed PTSD patients.
Glaciers in the eastern Pamir have reportedly been gaining mass during recent decades, even though glaciers in most other regions in High Mountain Asia have been in recession. Questions still remain about whether the trend is strengthening or weakening, and how far the positive balances extend into the eastern Pamir. To address these gaps, we use three different digital elevation models to reconstruct glacier surface elevation changes over two periods (2000–09 and 2000–15/16). We characterize the eastern Pamir as a zone of transition from positive to negative mass balance with the boundary lying at the northern end of Kongur Tagh, and find that glaciers situated at higher elevations are those with the most positive balances. Most (67% of 55) glaciers displayed a net mass gain since the 21st century. This led to an increasing regional geodetic glacier mass balance from −0.06 ± 0.16 m w.e. a−1 in 2000–09 to 0.06 ± 0.04 m w.e. a−1 in 2000–15/16. Surge-type glaciers, which are prevalent in the eastern Pamir, showed fluctuations in mass balance on an individual scale during and after surges, but no statistical difference compared to non-surge-type glaciers when aggregated across the region.
Although prenatal exposure to high ambient temperatures were reported to be associated with preterm birth, limited research assessed the impact of weather-related extreme heat events (EHE) on birthweight, particularly by trimester. We, therefore, investigated the impact of prenatal EHE on birthweight among term babies (tLBW) by trimester and birthweight percentile. We conducted a population-based case–control study on singleton live births at 38–42 gestational weeks in New York State (NYS) by linking weather data with NYS birth certificates. A total of 22,615 cases were identified as birthweight <2500 gram, and a random sample of 139,168 normal birthweight controls was included. EHE was defined as three consecutive days with the maximum temperatures of ≥32.2 °C/90 °F (EHE90) and two consecutive days of temperatures ≥97th percentile (EHE97) based on the distribution of the maximum temperature for the season and region. We estimated odds ratios (ORs) and 95% confidence intervals (95% CI) with multivariable unconditional logistic regression, controlling for confounders. Overall exposure to EHE97 for 2 d was associated with tLBW (OR 1.05; 95% CI 1.02, 1.09); however, the strongest associations were only observed in the first trimester for both heat indicators, especially when exposure was ≥3 d (ORs ranged: 1.06–1.13). EHE in the first trimester was associated with significant reduction in mean birthweight from 26.78 gram (EHE90) to 36.25 gram (EHE97), which mainly affected the 40th and 60th birthweight percentiles. Findings revealed associations between multiple heat indicators and tLBW, where the impact was consistently strongest in the first trimester.
Losing one's only child is a major traumatic life event that may lead to post-traumatic stress disorder (PTSD); however, the underlying mechanisms of its psychological consequences remain poorly understood. Here, we investigated subregional hippocampal functional connectivity (FC) networks based on resting-state functional magnetic resonance imaging and the deoxyribonucleic acid methylation of the human glucocorticoid receptor gene (NR3C1) in adults who had lost their only child.
A total of 144 Han Chinese adults who had lost their only child (51 adults with PTSD and 93 non-PTSD adults [trauma-exposed controls]) and 50 controls without trauma exposure were included in this fMRI study (age: 40–67 years). FCs between hippocampal subdivisions (four regions in each hemisphere: cornu ammonis1 [CA1], CA2, CA3, and dentate gyrus [DG]) and methylation levels of the NR3C1 gene were compared among the three groups.
Trauma-exposed adults, regardless of PTSD diagnosis, had weaker positive FC between the left hippocampal CA1, left DG, and the posterior cingulate cortex, and weaker negative FC between the right CA1, right DG, and several frontal gyri, relative to healthy controls. Compared to non-PTSD adults, PTSD adults showed decreased negative FC between the right CA1 region and the right middle/inferior frontal gyri (MFG/IFG), and decreased negative FC between the right DG and the right superior frontal gyrus and left MFG. Both trauma-exposed groups showed lower methylation levels of the NR3C1 gene.
Adults who had lost their only child may experience disrupted hippocampal network connectivity and NR3C1 methylation status, regardless of whether they have developed PTSD.
In this paper, we review the status of the multifunctional experimental platform at the National Laboratory of High Power Laser and Physics (NLHPLP). The platform, including the SG-II laser facility, SG-II 9th beam, SG-II upgrade (SG-II UP) facility, and SG-II 5 PW facility, is operational and available for interested scientists studying inertial confinement fusion (ICF) and a broad range of high-energy-density physics. These facilities can provide important experimental capabilities by combining different pulse widths of nanosecond, picosecond, and femtosecond scales. In addition, the SG-II UP facility, consisting of a single petawatt system and an eight-beam nanosecond system, is introduced including several laser technologies that have been developed to ensure the performance of the facility. Recent developments of the SG-II 5 PW facility are also presented.
Enterovirus A-71 (EV-A71) may be fatal, but the natural history, symptoms, and signs are poorly understood. This study aimed to examine the natural history of fatal EV-A71 infection and to identify the symptoms and signs of early warning of deterioration. This was a clinical observational study of fatal cases of EV-A71 infection treated at five Chinese hospitals between 1 January 2010 and 31 December 2012. We recorded and analysed 91 manifestations of EV-A71 infection in order to identify early prognosis indicators. There were 54 fatal cases. Median age was 21.5 months (Q1−Q3: 12–36). The median duration from onset to death was 78.5 h (range, 6 to 432). The multilayer perceptron analysis showed that ataxia respiratory, ultrahyperpyrexia, excessive tachycardia, refractory shock, absent pharyngeal reflex, irregular respiratory rhythm, hyperventilation, deep coma, pulmonary oedema and/or haemorrhage, excessive hypertension, tachycardia, somnolence, CRT extension, fatigue or sleepiness and age were associated with death. Autopsy findings (n = 2) showed neuronal necrosis, softening, perivascular cuffing, colloid and neuronophagia phenomenon in the brainstem. The fatal cases of enterovirus A71 had neurologic involvement, even at the early stage. Direct virus invasion through the neural pathway and subsequent brainstem damage might explain the rapid progression to death.
The degradation, alteration and depletion of riparian habitats caused by river regulation are among critical conservation concerns. Aquatic and riparian habitats support not only river-dwelling biota such as macroinvertebrates and fish, but also waterbirds, the top predators in the aquatic food web. Despite the intimate relationships between fish and waterbirds, the two groups are often investigated separately. Using an integrative approach, we examined the effects of dams on fish and scaly-sided merganser (Mergus squamatus), an endangered, iconic riverine species, where the lack of knowledge about habitat preferences greatly hampers long-term conservation efforts. Our analysis quantified three causal links: (1) water depth had direct, comparable, negative effects on both fish and waterbirds, and the path coefficients for fish and birds are –0.31 and –0.46, respectively; (2) river landscape heterogeneity directly and positively affected fish and waterbirds, and the path coefficients for fish and birds are 0.63 and 0.19, respectively; and (3) depth and river landscape also exerted indirect effects on waterbirds through their impacts on fish abundance, and the path coefficients for fish and birds are –0.15 and 0.28, respectively. Our findings could contribute to the rational spatial planning and sustainable operation of dams in that maintaining instream habitat availability and heterogeneity would benefit the whole riverine ecosystem.
Ball milling induced the formation of nanocrystalline and amorphization phase in Fe–25.68% Dy2O3 powder mixtures (mass fraction, %). The microstructure was investigated by using X-ray diffraction and transmission electron microscopy. The transformation of Dy2O3 from cubic to monoclinic crystal structure and then to the amorphization was observed during ball milling. A few Dy atoms were dissolved into Fe crystal structure, which was discussed using mechanical kinetics. After 48 h of ball milling, the homogenous mixtures of supersaturated nanocrystalline solid solution of Fe (Dy, O) and Dy2O3 amorphization were formed and the elements of Fe, Dy, and O were distributed uniformly in the ball-milled particles. During the whole ball mining process, a rapid decrease in Fe grain size was observed over the initial time period, while a constant value was presented in later stage, resulting in a final size of about 20 nm. The mechanism of the microstructural evolution of powder mixtures was analyzed and discussed.
The first reports of accurate skeletal muscle mass measurement in human subjects appeared at about the same time as introduction of the sarcopenia concept in the late 1980s. Since then these methods, computed tomography and MRI, have been used to gain insights into older (i.e. anthropometry and urinary markers) and more recently developed and refined methods (ultrasound, bioimpedance analysis and dual-energy X-ray absorptiometry) of quantifying regional and total body skeletal muscle mass. The objective of this review is to describe the evolution of these methods and their continued development in the context of sarcopenia evaluation and treatment. Advances in these technologies are described with a focus on additional quantifiable measures that relate to muscle composition and ‘quality’. The integration of these collective evaluations with strength and physical performance indices is highlighted with linkages to evaluation of sarcopenia and the spectrum of related disorders such as sarcopenic obesity, cachexia and frailty. Our findings show that currently available methods and those in development are capable of non-invasively extending measures from solely ‘mass’ to quality evaluations that promise to close the gaps now recognised between skeletal muscle mass and muscle function, morbidity and mortality. As the largest tissue compartment in most adults, skeletal muscle mass and aspects of muscle composition can now be evaluated by a wide array of technologies that provide important new research and clinical opportunities aligned with the growing interest in the spectrum of conditions associated with sarcopenia.
We have clarified the performance of two tungsten–helium analytical interatomic potentials, one of which, developed by Li et al., is a bond-order potential, and another, developed by Juslin et al., is a combination of embedded atom method potential and pair potential. Using these two potentials, we have simulated and made a full comparison of formation energy and migration energy of different defects including helium and vacancy, binding energies of helium and vacancy with helium-vacancy cluster, surface energy, as well as melting point, with reference to the corresponding results from the first-principles and experiments.
The weightless planar 2R underactuated manipulators with passive last joint are considered in this paper for investigating a feasible method to stabilize the system, which is a second-order nonholonomic-constraint mechanical system with drifts. The characteristics including the controllability of the linear approximation model, the minimum phase property, the Small Time Local Controllability (STLC), the differential flatness, and the exactly nilpotentizable properties, are analyzed. Unfortunately, these negative characteristics indicate that the simplest underactuated mechanical system is difficult to design a stable closed-loop control system. In this paper, nilpotent approximation and iterative steering methods are utilized to solve the problem. A globally effective nilpotent approximation model is developed and the parameterized polynomial input is adopted to stabilize the system to its non-singularity equilibrium configuration. In accordance with this scheme, it is shown that designing a stable closed-loop control system for the underactuated mechanical system can be ascribed to solving a set of nonlinear algebraic equations. If the nonlinear algebraic equations are solvable, then the controller is asymptotically stable. Some numerical simulations demonstrate the effectiveness of the presented approach.
Clathrin heavy chain 1 (CLTC) has been considered a “moonlighting protein” which acts in membrane trafficking during interphase and in stabilizing spindle fibers during mitosis. However, its roles in meiosis, especially in mammalian oocyte maturation, remain unclear. This study investigated CLTC expression and function in spindle formation and chromosome congression during mouse oocyte meiotic maturation. Our results showed that the expression level of CLTC increased after germinal vesicle breakdown (GVBD) and peaked in the M phase. Immunostaining results showed CLTC distribution throughout the cytoplasm in a cell cycle-dependent manner. Appearance and disappearance of CLTC along with β-tubulin (TUBB) could be observed during spindle dynamic changes. To explore the relationship between CLTC and microtubule dynamics, oocytes at metaphase were treated with taxol or nocodazole. CLTC colocalized with TUBB at the enlarged spindle and with cytoplasmic asters after taxol treatment; it disassembled and distributed into the cytoplasm along with TUBB after nocodazole treatment. Disruption of CLTC function using stealth siRNA caused a decreased first polar body extrusion rate and extensive spindle formation and chromosome congression defects. Taken together, these results show that CLTC plays an important role in spindle assembly and chromosome congression through a microtubule correlation mechanism during mouse oocyte maturation.
Characteristic boundary conditions that are capable of handling general fluid mixtures flow at all flow speeds are developed. The formulation is based on fundamental thermodynamics theories incorporated into an efficient preconditioning scheme in a unified manner. Local one-dimensional inviscid (LODI) relations compatible to the preconditioning system are proposed to obtain information carried by incoming characteristic waves at boundaries accurately. The approach has been validated against a variety of sample problems at a broad range of fluid states and flow speeds. Both acoustic waves and hydrodynamic flow features can pass through the boundaries of computational domain transparently without any un-physical reflection or spurious distortion. The approach can be reliably applied to fluid flows at extensive thermodynamic states and flow speeds in numerical simulations. Moreover, the use of the boundary condition shows to improve the computational efficiency.
Kashin-Beck disease (KBD) is a chronic endemic osteoarthropathy, which mainly occurs in West and Northeast China. Epidemiological studies suggest that Se deficiency is an important environmental factor for the incidence of KBD. Glutathione peroxidase 4 (GPx4) belongs to the glutathione peroxidase family, which is crucial for optimal antioxidant defences. Our purpose is to investigate the putative association between GPx4 polymorphisms and the risk of KBD. Restriction fragment length polymorphism-PCR was used to detect two SNP (rs713041, rs4807542) in 219 cases and 194 controls in Han Chinese subjects, and quantitative analysis for the GPx4 mRNA level was performed by the real-time PCR method. The results revealed that linkage disequilibrium existed in the two SNP. A significant difference was observed in the haplotype A-T (P = 0·0066) of GPx4, which was obviously lower in the KBD cases (0·006 v. 0·032 %). Correlation analysis based on a single locus showed no association between each SNP and KBD risk. Furthermore, the GPx4 mRNA level was dramatically lower in the blood of KBD patients. Overall, our finding indicated GPx4 polymorphisms and decreased mRNA level may be related to the development of KBD in the Chinese population, suggesting GPx4 as a possible candidate susceptibility gene for KBD.
Survivin is a novel member of the inhibitor of apoptosis gene family that bear baculoviral IAP repeats (BIRs), whose physiological roles in regulating meiotic cell cycle need to be determined. Confocal microscopy was employed to observe the localization of survivin in rat oocytes. At the germinal vesicle (GV) stage, survivin was mainly concentrated in the GV. At the prometaphase I (pro-MI) and metaphase I (MI) stage, survivin was mainly localized at the kinetochores, with a light staining detected on the chromosomes. After transition to anaphase I or telophase I stage, survivin migrated to the midbody, and signals on the kinetochores and chromosomes disappeared. At metaphase II (MII) stage, survivin became mainly localized at the kinetochores again. Microinjection of oocytes with anti-survivin antibodies at the beginning of the meiosis, thus blocking the normal function of survivin, resulted in abnormal spindle assembly, chromosome segregation and first polar body emission. These results suggest that survivin is involved in regulating the meiotic cell cycle in rat oocytes.
5-AZA-2′-deoxycytidine (5-AZA-CdR) is a demethylating, teratogenic agent and a mutagen, which causes defects in the developing mouse and rat after implantation. Our previous data indicated that 5-AZA-CdR (0.2 and 1.0 μM) inhibited the development of mouse preimplantation embryos. Pronuclear embryos exposed to 5-AZA-CdR at the pronuclear stage were unable to form 8-cell embryos, while 2-cell-stage embryos exposed to 5-AZA-CdR only developed into uncompacted 8-cell-stage embryos. And there was no formation of blastocysts when 4-cell embryos cultured in 5-AZA-CdR. In our present study, we detected Dnmt1o protein and some developmental gene expression in order to find the reasons for the developmental arrest. Dnmt1o could not traffic to 8-cell nuclei as control when embryos were exposed to 5-AZA-CdR. Dnmt1o was in cytoplasm at 2-cell and 4-cell stages before and after treated with 5-AZA-CdR. Gene expression changes were also detected in this research. Our data indicated that connexin 31 (Cx31), connexin 43 (Cx43), connexin 45 (Cx45), E-cadherin (Cdh1) and β-catenin (Ctnnb1) were all downregulated by 5-AZA-CdR. Cx31, Cx43 and Cx45 are members of connexins family, which have a central role in gap junctions. Cdh1 and Ctnnb1 are necessary for the foundation of tight junctions. Therefore, developmental arrest induced by 5-AZA-CdR may be caused by the failure of Dnmt1o cytoplasmic–nuclear traffic and the down-regulation of developmental gene expression. Normal compaction and blastocoel cavitation need Dnmt1o traffic to 8-cell nuclei and the right gene expression, especially the correlative genes in gap junctions and tight junctions.