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This study investigates the dynamics of low-viscosity nanodroplets impacting surfaces with static contact angles from θ = 73° to 180° via molecular dynamics (MD) simulations. Two typical morphologies of impacting nanodroplets are observed at the maximum spreading state, a Hertz-ball-like in a low-Weber-number range and a thin-film-like in a high-Weber-number range. Only inertial and capillary forces dominate the impact for the former, whereas viscous force also becomes dominant for the latter. Regardless of morphologies at the maximum spreading state, the ratio of spreading time to contact time always remains constant on an ideal superhydrophobic surface with θ = 180°. With the help of different kinematic approximations of the spreading time and scaling laws of the contact time, scaling laws of the maximum spreading factor ${\beta _{max}}\sim W{e^{1/5}}$ in the low-Weber-number range (capillary regime) and ${\beta _{max}}\sim W{e^{2/3}}R{e^{ - 1/3}}$ (or ${\beta _{max}}\sim W{e^{1/2}}O{h^{1/3}}$) in the high-Weber-number range (cross-over regime) are obtained. Here, We, Re, and Oh are the Weber number, Reynolds number, and Ohnesorge number, respectively. Although the scaling laws are proposed only for the ideal superhydrophobic surface, they are tested valid for θ over 73° owing to the ignorable zero-velocity spreading effect. Furthermore, combining the two scaling laws leads to an impact number, $W{e^{3/10}}O{h^{1/3}} = 2.1$. This impact number can be used to determine whether viscous force is ignorable for impacting nanodroplets, thereby distinguishing the capillary regime from the cross-over regime.
High-resolution X-ray flash radiography of Ti characteristic lines with a multilayer Kirkpatrick–Baez microscope was developed on the Shenguang-II (SG-II) Update laser facility. The microscope uses an optimized multilayer design of Co/C and W/C stacks to obtain a high reflection efficiency of the Ti characteristic lines while meeting the precise alignment requirement at the Cu Kα line. The alignment method based on dual simulated balls was proposed herein, which simultaneously realizes an accurate indication of the center field of view and the backlighter position. The optical design, multilayer coatings, and alignment method of the microscope and the experimental result of Ti flash radiography of the Au-coned CH shell target on the SG-II Update are described.
In this paper, the generation of relativistic electron mirrors (REMs) and the reflection of an ultra-short laser off this mirrors are discussed, applying two-dimensional particle-in-cell (2D-PIC) simulations. REMs with ultra-high acceleration and expanding velocity can be produced from a solid nanofoil illuminated normally by an ultra-intense femtosecond laser pulse with a sharp rising edge. Chirped attosecond pulse can be produced through the reflection of a counter-propagating probe laser off the accelerating REM. In the electron moving frame, the plasma frequency of the REM keeps decreasing due to its rapidly expanding. The laser frequency, on the contrary, keeps increasing due to the acceleration of REM and the relativistic Doppler shift from the lab frame to the electron moving frame. Within an ultra-short time interval, the two frequencies will be equal in the electron moving frame, which leads the resonance between laser and REM. The reflected radiation near this interval and the corresponding spectra will be amplified due to the resonance. Through adjusting the arriving time of the probe laser, certain part of the reflected field could be selectively amplified or depressed, leading to the selectively adjusting of the corresponding spectra.
The study of enclaves in granitic plutons provides fundamental information on the petrogenesis of their host rocks. Here we combine U–Pb zircon ages, petrography, geochemistry and Nd–Hf isotope composition to investigate the origin of dioritic–granodioritic enclaves and their host granodiorites and biotite granites in the Xuehuading–Panshanchong area, which is a pivotal site to study the Palaeozoic intracontinental orogenic processes of the South China Block. Obtained ages indicate that the host rocks were formed in early Silurian time (c. 432 Ma). The enclaves are fine grained, but with mineral assemblages similar to their hosts and contain amphibole, biotite and plagioclase. All rocks have fractionated rare earth element patterns ((La/Yb)N = 2.86–8.16), except for one biotite granite that has a concave rare earth element pattern ((La/Yb)N = 1.50). Most rocks are depleted in Ta–Nb–Ti, and have negative Eu anomalies and ϵNd(t) (–8.86 to –5.75) and zircon ϵHf(t) (–13.30 to –4.11, except for one, –39.08). We interpret that the enclaves were formed at the borders of magma-ascending conduits, where the mafic mineral crystallization was enhanced by rapid cooling. Conversely, the biotite granites were produced by fractional crystallization from a related granodiorite magma. The sample with a concave rare earth element pattern may have been influenced by hydrothermal fluid–melt interaction. Geochemical modelling suggests that the granodiorites were likely generated by disequilibrium melting of heterogeneous amphibolites in the middle–lower crust. Considering the geological data for the Palaeozoic magmatic rocks in the South China Block, we propose that the Xuehuading–Panshanchong magmatism was likely triggered by piecemeal removal of the thickened lithospheric root and subsequent thermal upwelling of mantle, without a mantle-derived magma contribution to the granites.
The novel coronavirus disease 2019 (COVID-19) pandemic has spread to over 213 countries and territories. We sought to describe the clinical features of fatalities in patients with severe COVID-19.
Methods:
We conducted an Internet-based retrospective cohort study through retrieving the clinical information of 100 COVID-19 deaths from nonduplicating incidental reports in Chinese provincial and other governmental websites between January 23 and March 10, 2020.
Results:
Approximately 6 of 10 COVID-19 deaths were males (64.0%). The average age was 70.7 ± 13.5 y, and 84% of patients were elderly (over age 60 y). The mean duration from admission to diagnosis was 2.2 ± 3.8 d (median: 1 d). The mean duration from diagnosis to death was 9.9 ± 7.0 d (median: 9 d). Approximately 3 of 4 cases (76.0%) were complicated by 1 or more chronic diseases, including hypertension (41.0%), diabetes (29.0%) and coronary heart disease (27.0%), respiratory disorders (23.0%), and cerebrovascular disease (12.0%). Fever (46.0%), cough (33.0%), and shortness of breath (9.0%) were the most common first symptoms. Multiple organ failure (67.9%), circulatory failure (20.2%), and respiratory failure (11.9%) are the top 3 direct causes of death.
Conclusions:
COVID-19 deaths are mainly elderly and patients with chronic diseases especially cardiovascular disorders and diabetes. Multiple organ failure is the most common direct cause of death.
The clinical characteristics of patients with COVID-19 were analysed to determine the factors influencing the prognosis and virus shedding time to facilitate early detection of disease progression. Logistic regression analysis was used to explore the relationships among prognosis, clinical characteristics and laboratory indexes. The predictive value of this model was assessed with receiver operating characteristic curve analysis, calibration and internal validation. The viral shedding duration was calculated using the Kaplan–Meier method, and the prognostic factors were analysed by univariate log-rank analysis and the Cox proportional hazards model. A retrospective study was carried out with patients with COVID-19 in Tianjin, China. A total of 185 patients were included, 27 (14.59%) of whom were severely ill at the time of discharge and three (1.6%) of whom died. Our findings demonstrate that patients with an advanced age, diabetes, a low PaO2/FiO2 value and delayed treatment should be carefully monitored for disease progression to reduce the incidence of severe disease. Hypoproteinaemia and the fever duration warrant special attention. Timely interventions in symptomatic patients and a time from symptom onset to treatment <4 days can shorten the duration of viral shedding.
Distinguished by a marked combination of high strength and high fracture toughness, 18Ni-300 maraging steel (MS) is widely used for intricate tool and die applications. MS is also amenable to the powder bed fusion additive manufacturing process, providing unique opportunities to make small features and incorporate cooling channels in molds. In this study, tensile test samples were fabricated using selective laser melting to investigate the effects of built height and orientations on the evolution of the microstructure and the mechanical properties of the samples. The microstructure of the as-fabricated samples consists of the primary α-martensite phase and fine cellular microstructure (~0.66–0.83 μm) with the retained austenite γ-phase aggregated at the boundaries of the cells, resulting in an enhanced mechanical performance compared with traditional counterparts under the same condition (without post-heat treatments). Random grain orientations with weak textures are revealed in all samples. The XY-built samples display better tensile performance when compared to the Z-built samples due to the fine grain sizes and the retained γ phase. The bottom of the Z-built sample exhibits a higher hardness than other parts of the sample, which could be attributed to its finer cellular structure.
Situated between the North China Craton to the east and the Tarim Craton to the west, the northern Alxa area in westernmost Inner Mongolia in China occupies a key location for interpreting the late-stage tectonic evolution of the southern Central Asian Orogenic Belt. New LA-ICP-MS zircon U–Pb dating results reveal 282.2 ± 3.9 Ma gabbros and 216.3 ± 3.2 Ma granites from the Yagan metamorphic core complex in northern Alxa, NW China. The gabbros are characterized by low contents of Si, Na, K, Ti and P and high contents of Mg, Ca, Al and Fe. These gabbros have arc geochemical signatures with relative enrichments in large ion lithophile elements and depletions in high field strength elements, as well as negative εNd(t) (−0.91 to −0.54) and positive εHf(t) (2.59 to 6.37) values. These features indicate that a depleted mantle magma source metasomatized by subduction fluids/melts and contaminated by crustal materials was involved in the processes of magma migration and emplacement. The granites show high-K calc-alkaline and metaluminous to weakly peraluminous affinities, similar to A-type granites. They have positive εNd(t) (1.55 to 1.99) and εHf(t) (5.03 to 7.64) values. These features suggest that the granites were derived from the mixing of mantle and crustal sources and formed in a postcollisional tectonic setting. Considering previous studies, we infer that the final closure of the Palaeo-Asian Ocean in the central part of the southern Central Asian Orogenic Belt occurred in late Permian to Early–Middle Triassic times.
Synaptotagmin 1 (Syt1) is an abundant and important presynaptic vesicle protein that binds Ca2+ for the regulation of synaptic vesicle exocytosis. Our previous study reported its localization and function on spindle assembly in mouse oocyte meiotic maturation. The present study was designed to investigate the function of Syt1 during mouse oocyte activation and subsequent cortical granule exocytosis (CGE) using confocal microscopy, morpholinol-based knockdown and time-lapse live cell imaging. By employing live cell imaging, we first studied the dynamic process of CGE and calculated the time interval between [Ca2+]i rise and CGE after oocyte activation. We further showed that Syt1 was co-localized to cortical granules (CGs) at the oocyte cortex. After oocyte activation with SrCl2, the Syt1 distribution pattern was altered significantly, similar to the changes seen for the CGs. Knockdown of Syt1 inhibited [Ca2+]i oscillations, disrupted the F-actin distribution pattern and delayed the time of cortical reaction. In summary, as a synaptic vesicle protein and calcium sensor for exocytosis, Syt1 acts as an essential regulator in mouse oocyte activation events including the generation of Ca2+ signals and CGE.
The base of the Emsian, which is defined by the first appearance of the conodont Polygnathus kitabicus, has never been successfully demonstrated in the South China Block (including Guangxi and eastern Yunnan). As a result, we studied conodonts from the lowermost part of the Shizhou Member of the Yukiang Formation at the Dacun-1 section in the Liujing area, Guangxi. This new investigation has revealed a conodont fauna only consisting of Polygnathus pireneae, P. sokolovi, P. kitabicus, P. sp. and Pandorinellina exigua philipi, which can be assigned to the uppermost part of the pireneae Zone and the lowermost part of the kitabicus Zone in ascending order. The Pragian/Emsian boundary at the Dacun-1 section is located in the highest thick-bedded limestone bed that can be observed in the lowermost part of the Shizhou Member. Therefore, this is the first time that the lower boundary of the Emsian defined by the lowest occurrence of P. kitabicus is reported in the South China Block. However, the scarcity of suitable limestone samples for conodont analysis in the middle and upper parts of the Shizhou Member precludes definitive identification of the upper boundary of the kitabicus Zone in the Liujing area.
Maternal one-carbon metabolism during pregnancy is crucial for fetal development and programming by DNA methylation. However, evidence on one-carbon biomarkers other than folate is lacking. We, therefore, investigated whether maternal plasma methyl donors, that is, choline, betaine and methionine, are associated with birth outcomes. Blood samples were obtained from 115 women during gestation (median 26·3 weeks, 90 % range 22·7–33·0 weeks). Plasma choline, betaine, methionine and dimethylglycine were measured using HPLC-tandem MS. Multivariate linear and logistic regression models were used to estimate the association between plasma biomarkers and birth weight, birth length, the risk of small-for-gestational-age and large-for-gestational-age (LGA). Higher level of maternal betaine was associated with lower birth weight (–130·3 (95 % CI –244·8, –15·9) per 1 sd increment for log-transformed betaine). Higher maternal methionine was associated with lower risk of LGA, and adjusted OR, with 95 % CI for 1 sd increase in methionine concentration was 0·44 (95 % CI 0·21, 0·89). Stratified analyses according to infant sex or maternal plasma homocysteine status showed that reduction in birth weight in relation to maternal betaine was only limited to male infants or to who had higher maternal homocysteine status (≥5·1 µmol/l). Higher maternal betaine status was associated with reduced birth weight. Maternal methionine was inversely associated with LGA risk. These findings are needed to be replicated in future larger studies.
Laser pulses of 200 ps with extremely high intensities and high energies are sufficient to satisfy the demand of shock ignition, which is an alternative path to ignition in inertial confinement fusion (ICF). This paper reports a type of Brillouin scheme to obtain high-intensity 200-ps laser pulses, where the pulse durations are a challenge for conventional pulsed laser amplification systems. In the amplification process, excited Brillouin acoustic waves fulfill the nonlinear optical effect through which the high energy of a long pump pulse is entirely transferred to a 200-ps laser pulse. This method was introduced and achieved within the SG-III prototype system in China. Compared favorably with the intensity of $2~\text{GW}/\text{cm}^{2}$ in existing ICF laser drivers, a 6.96-$\text{GW}/\text{cm}^{2}$ pulse with a width of 170 ps was obtained in our experiment. The practical scalability of the results to larger ICF laser drivers is discussed.
The present study was undertaken to investigate the antiparasitic activity of extracellular products of Streptomyces albus. Bioactivity-guided isolation of chloroform extracts affording a compound showing potent activity. The structure of the compound was elucidated as salinomycin (SAL) by EI-MS, 1H NMR and 13C NMR. In vitro test showed that SAL has potent anti-parasitic efficacy against theronts of Ichthyophthirius multifiliis with 10 min, 1, 2, 3 and 4 h (effective concentration) EC50 (95% confidence intervals) of 2.12 (2.22–2.02), 1.93 (1.98–1.88), 1.42 (1.47–1.37), 1.35 (1.41–1.31) and 1.11 (1.21–1.01) mg L−1. In vitro antiparasitic assays revealed that SAL could be 100% effective against I. multifiliis encysted tomonts at a concentration of 8.0 mg L−1. In vivo test demonstrated that the number of I. multifiliis trophonts on Erythroculter ilishaeformis treated with SAL was markedly lower than that of control group at 10 days after exposed to theronts (P < 0.05). In the control group, 80% mortality was observed owing to heavy I. multifiliis infection at 10 days. On the other hand, only 30.0% mortality was recorded in the group treated with 8.0 mg L−1 SAL. The median lethal dose (LD50) of SAL for E. ilishaeformis was 32.9 mg L−1.
For the first time, an experiment has been conducted to investigate synthetic jet laminar vortex rings impinging onto porous walls with different geometries by time-resolved particle image velocimetry. The geometry of the porous wall is changed by varying the hole diameter on the wall (from 1.0 mm to 3.0 mm) when surface porosity is kept constant ($\unicode[STIX]{x1D719}=75\,\%$). The finite-time Lyapunov exponent and phase-averaged vorticity field derived from particle image velocimetry data are presented to reveal the evolution of the vortical structures. A mechanism associated with vorticity cancellation is proposed to explain the formation of downstream transmitted vortex rings; and both the vortex ring trajectory and the time-mean flow feature are compared between different cases. It is found that the hole diameter significantly influences the evolution of the flow structures on both the upstream and downstream sides of the porous wall. In particular, for a porous wall with a small hole diameter ($d_{h}^{\ast }=0.067$, 0.10 and 0.133), the transmitted finger-type jets will reorganize into a well-formed transmitted vortex ring in the downstream flow. However, for the case of a large hole diameter of $d_{h}^{\ast }=0.20$, the transmitted vortex ring is not well formed because of insufficient vorticity cancellation. Additionally, the residual vorticity gradually evolves into discrete jet-like structures downstream, which further weaken the intensity of the transmitted vortex ring. Consequently, the transmitted flow structures for the $d_{h}^{\ast }=0.20$ case would lose coherence more easily (or probably even transition to turbulence), resulting in a faster decay of the axial velocity and stronger entrainment of the transmitted jet. For all porous wall cases, the velocity profile of the transmitted jet exhibits self-similar behaviour in the far field ($z/D_{0}\geqslant 6.03$), which agrees well with the velocity distribution of free synthetic jets. With the help of the control-volume approach, the time-mean drag of the porous wall is evaluated experimentally for the first time. It is shown that the porous wall drag increases with the decrease in the hole diameter. Moreover, for a porous wall with a small hole diameter ($d_{h}^{\ast }=0.067$, 0.10 and 0.133), it appears that the porous wall drag mainly derives from the viscous effect. However, as $d_{h}^{\ast }$ increases to 0.20, the form drag associated with the porous wall geometry becomes significant.
Excavation of the Han Dynasty chambered tomb at Laoguanshan in Chengdu, south-west China, has provided the earliest known evidence of pattern loom technology. Four model looms, along with accompanying artefacts and figurines relating to the weaving process, give insight into the technique of jin silk production. The discovery is hugely significant as it provides the first direct evidence of pattern-weave textile production in ancient China. Jin silk, made using this method, was both valuable and widely distributed, and the design of the machine influenced the invention of later looms and the spread of technology throughout Eurasia and Europe, representing great technological accomplishment for the second century BC.
Phase stability, elastic, and thermodynamic properties of (Co,Ni)3(Al,Mo,Nb) with the L12 structure have been investigated by first-principles calculations. Calculated phonon density of states show that (Co,Ni)3(Al,Mo,Nb) is dynamically stable, and calculated elastic constants indicate that (Co,Ni)3(Al,Mo,Nb) possesses intrinsic ductility. Young’s and shear moduli of the simulated polycrystalline (Co,Ni)3(Al,Mo,Nb) phase are calculated using the Voigt–Reuss–Hill approach and are found to be smaller than those of Co3(Al,W). Calculated electronic density of states depicts covalent-like bonding existing in (Co,Ni)3(Al,Mo,Nb). Temperature-dependent thermodynamic properties of (Co,Ni)3(Al,Mo,Nb) can be described satisfactorily using the Debye–Grüneisen approach, including heat capacity, entropy, enthalpy, and linear thermal expansion coefficient. Predicted heat capacity, entropy, and linear thermal expansion coefficient of (Co,Ni)3(Al,Mo,Nb) show significant change as a function of temperature. Furthermore the obtained data can be used in the modeling of thermodynamic and mechanical properties of Co-based alloys to enable the design of high temperature alloys.
Beginning in 2007, all newly diagnosed cancer patients at the Koo Foundation Sun Yat-Sen Cancer Center (KF–SYSCC) were screened for psychosocial distress. Our social workers, as part of the psychosocial care team (PCT), have engaged in proactive outreach with patients identified as distressed. The goal of the present study was to assess the prevalence of psychosocial distress and the extent of contact between the PCT and distressed patients.
Method:
Newly diagnosed patients who were treated at KF–SYSCC between 2007 and 2010 for cancer were eligible if there were at least 100 patients with the same type of cancer. Before treatment began, they were screened with the Pain Scale and the Distress Thermometer (DT) and had the option to specify a desire for help. The rates of distress were analyzed by cancer type and by probable related factors. Information regarding contact with the PCT was retrieved from computerized databases.
Results:
Overall, some 5,335 cancer patients representing 12 major cancer types were included in our study. Of these, 1,771 (33.20%) were significantly distressed. By multivariate logistic regression, younger age, female gender, higher pain score, and disease stage, but not cancer type, were found to be associated with higher rates of distress. Among these distressed patients, 628 (36%) had some contact with the PCT.
Significance of results:
This Taiwanese study with a large sample size revealed a prevalence rate of psychosocial distress similar to rates found in Western countries. Contact with the PCT was established in only 36% of significantly distressed patients, despite a proactive outreach program. It is very important to have screening results made available in a timely fashion to the psycho-oncology team so that appropriate care can be offered promptly.
The present study was performed to identify the genotype of a hypertrophic cardiomyopathy family and investigate the clinicopathogenic characteristics and prognostic features of relevant genetic abnormalities. Target sequence capture sequencing was performed to screen for pathogenic alleles in a 32-year-old female patient (proband). Sanger sequencing was carried out to verify the results. Sanger sequencing was also performed on other family members to identify allele carriers. A survival analysis was carried out using published literature and our findings. We found that the proband and her son harboured a Gly716Arg sequence variant of the β-myosin heavy chain. Neither the proband’s father nor the mother were carriers of this sequence variant; thus, the mutation was classified as “de novo”. Further survival analysis revealed that female patients appear to have a longer life expectancy compared with males. Our study may provide an effective approach for the genetic diagnosis of hypertrophic cardiomyopathy.
A defect in the intestinal barrier is one of the characteristics of Crohn's disease (CD). The tight junction (TJ) changes and death of epithelial cells caused by intestinal inflammation play an important role in the development of CD. DHA, a long-chain PUFA, has been shown to be helpful in treating inflammatory bowel disease in experimental models by inhibiting the NF-κB pathway. The present study aimed at investigating the specific effect of DHA on the intestinal barrier function in IL-10-deficient mice. IL-10-deficient mice (IL-10− / −) at 16 weeks of age with established colitis were treated with DHA (i.g. 35·5 mg/kg per d) for 2 weeks. The severity of their colitis, levels of pro-inflammatory cytokines, epithelial gene expression, the distributions of TJ proteins (occludin and zona occludens (ZO)-1), and epithelial apoptosis in the proximal colon were measured at the end of the experiment. DHA treatment attenuated the established colitis and was associated with reduced infiltration of inflammatory cells in the colonic mucosa, lower mean histological scores and decreased levels of pro-inflammatory cytokines (IL-17, TNF-α and interferon-γ). Moreover, enhanced barrier function was observed in the DHA-treated mice that resulted from attenuated colonic permeability, rescued expression and corrected distributions of occludin and ZO-1. The results of the present study indicate that DHA therapy may ameliorate experimental colitis in IL-10− / − mice by improving the intestinal epithelial barrier function.
Common psychiatric disorders are highly heritable, indicating that genetic factors play an important role in their aetiology. The CACNA1C gene, which codes for subunit alpha-1C of the Cav1.2 voltage-dependent L-type calcium channel, has been consistently found to be the shared risk gene for several kinds of mental disorder.
Aims
To investigate whether CACNA1C is a susceptibility gene for schizophrenia and major depressive disorder in the Han Chinese population.
Method
We carried out a case–control study of 1235 patients with schizophrenia, 1045 with major depressive disorder and 1235 healthy controls. A tag single nucleotide polymorphism (SNP) rs1006737 along with another 10 tag SNPs in the CACNA1C gene were genotyped in all samples.
Results
We found that rs1006737 was associated with both schizophrenia (Pallele = 0.0014, Pgenotype = 0.006, odds ratio (OR) = 1.384, 95% CI 1.134–1.690) and major depressive disorder (Pallele = 0.0007, Pgenotype = 0.003, OR = 1.425, 95% CI 1.160–1.752).
Conclusions
Our findings support CACNA1C being a risk gene for both schizophrenia and major depressive disorder in the Han Chinese population.