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Extant medusozoans (phylum Cnidaria) are dominated by forms showing tetraradial symmetry, but stem-group medusozoans of early Cambrian age collectively exhibit tetra-, bi-, penta-, and hexaradial symmetry. Moreover, the developmental and evolutionary relationships between four-fold and other types of radial symmetry in medusozoans remain poorly understood. Here we describe a new hexangulaconulariid, Septuconularia yanjiaheensis new genus new species, from Bed 5 of the Yanjiahe Formation (Cambrian Stage 2) in the Three Gorges area of Hupei Province, China. The laterally compressed, biradially symmetrical periderm of this species possesses 14 gently tapered faces, the most of any hexangulaconulariid described thus far. The faces are bordered by longitudinal ridges and crossed by short, irregularly spaced transverse ribs. Longitudinally, the periderm consists of three regions that probably correspond, respectively, to an embryonic stage, a transient juvenile stage, and a long adult stage. Septuconularia yanjiaheensis may have been derived from six-faced Hexaconularia (Fortunian Stage), which is morphologically intermediate between Septuconularia yanjiaheensis and Arthrochites. Furthermore, conulariids sensu stricto, carinachitids, and hexangulaconulariids may constitute a monophyletic group united by possession of an organic or organophosphatic periderm exhibiting longitudinal (corner) sulci, a facial midline, and offset of transverse ribs along the facial midline.
We investigate the dynamic evolution of the price discovery function in Chinese agricultural futures markets using a newly developed rolling window cointegration approach. The results show that, compared with wheat and rice, the futures-spot cointegration relationship in the soybean and corn markets tends to be more durable and frequent. Dynamic cointegration analysis indicates that the recent market-oriented reforms in China have boosted the price discovery function of soybean and corn futures markets, whereas price stabilization policies tend to weaken the price discovery function of futures markets. The difference in price discovery function is attributed to differences in market mechanisms and Chinese agricultural policies.
Excessive intake of high-energy diets is an important cause of most obesity. The intervention of rats with high-fat diet can replicate the ideal animal model for studying the occurrence of human nutritional obesity. The proteomics and bioinformatics analysis can help us to systematically and comprehensively study the effect of high-fat diet on rat liver. In this study, 4056 proteins were identified in rat liver by using tandem mass tag. A total of 198 proteins were significantly changed, of which 103 were significantly up-regulated and 95 were significantly down-regulated. These significant differentially expressed proteins are primarily involved in lipid metabolism and glucose metabolism processes. The intake of a high-fat diet forces the body to maintain physiological balance by regulating these key protein spots to inhibit fatty acid synthesis, promote fatty acid oxidation, and accelerate fatty acid degradation. This study enriches our understanding of metabolic disorders induced by high-fat diets at the protein level.
This study examined Echinococcus spp. genotypes and genetic variants isolated from humans as well as domestic and wild animals from the Qinghai-Tibetan Plateau Area using the cox1 gene. All samples except the pika isolates were identified as the Echinococcus granulosus sensu stricto. Sixteen different haplotypes with considerable intraspecific variation were detected and characterized in mitochondrial cox1 sequences. The parsimonious network of cox1 haplotypes showed star-like features, and the neutrality indexes computed via Tajima's D and Fu's Fs tests showed high negative values in E. granulosus s. s., indicating deviations from neutrality; the Fst values were low among the populations, implying that the populations were not genetically differentiated. The pika isolates were identified as E. multilocularis and E. shiquicus. Only one haplotype was recognized in the pika isolates. E. granulosus s. s. was the predominant species found in animals and humans, followed by E. multilocularis and E. shiquicus, with high genetic diversity circulating among the animals and humans in this area. Further studies are needed to cover many sample collection sites and larger numbers of pathogen isolates, which may reveal abundant strains and/or other haplotypes in the hydatid cysts infecting human and animal populations of the QTPA, China.
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.
Residual strain often occurs in metal when it was subjected to the tension load, random vibration, or high impact. The mild steel was selected as the research object, and the feasibility of using nonlinear ultrasonic technique to characterize the residual strain was investigated in this paper. First, the mild steel specimens were stretched to several different kinds of stress, then the nonlinear effect as well as the microstrain of each sample was measured. The results indicate that the microstrain increases with increasing applied stress and reaches a maximum value of about 0.036% as the tensile stress increases to the elastic limit. Compared with the original specimen, the nonlinear parameter of tensile specimen gradually increased within the elastic limit. This result reveals that the variation of nonlinear parameter was related to microstrain in mild steel, because the microstructure observation demonstrated that the dislocation structure was basically unchanged within the elastic limit. This research indicates that the nonlinear ultrasonic method has the promising potential to characterize the microstrain in metals.
Anti-solvent treatment assisted crystallization is currently one of the most widely used methods to obtain high-quality perovskite films ascribed to its great operability. However, choosing a proper anti-solvent toward high-quality perovskite film for perovskite solar cells (PSCs) remains elusive. In this study, we qualitatively evaluate the impact of anti-solvent treatment on the grain growth and phase composition of perovskite by X-ray diffraction, scanning electron microscope, Fourier transform infrared spectrometer, and UV-vis absorption measurement, etc. The results demonstrate that the chemical groups in anti-solvents also affect the formation of perovskites, and anti-solvents with a low boiling point and good polarity contribute to the superior efficiency and reproducibility of PSCs. The device prepared using ether as an anti-solvent exhibits the best power conversion efficiency of 18.47%. The results indicate a new path toward selecting an ideal anti-solvent to improve the performance of PSCs.
High-peak-power transform-limited narrow-linewidth nanosecond all-fiber lasers are desired in a range of applications. However, their linewidths will be broadened by self-phase modulation (SPM). We propose a novel concept that generates transform-limited laser pulses by temporally shaping the pulse seed. The impact of the pulse shape on SPM-induced spectral broadening was studied numerically and experimentally. It was found theoretically that the square-shape pulsed laser is immune to SPM-induced spectral broadening. Based on this principle, we built a high-peak-power, linearly polarized, square-shape nanosecond all-fiber laser in a master oscillator power amplifier (MOPA) configuration. Stimulated Brillouin scattering (SBS) limited peak powers of 4.02 kW, 5.06 kW, 6.52 kW and 9.30 kW were obtained at pulse widths of 8 ns, 7 ns, 6 ns and 5 ns. Thanks to the square-shape pulsed seed, the linewidths at maximum peak power remained at 129.5 MHz, 137.6 MHz, 156.2 MHz and 200.1 MHz, respectively, close to the transform-limited values of 110.8 MHz, 126.6 MHz, 147.7 MHz and 177.3 MHz.
We highlight the current understanding of mechanisms of phase transformation, strengthening, and the role of alloying elements in aluminum, magnesium, and titanium alloys, including nucleation and growth of precipitates, precipitate–dislocation interactions, solute segregation at precipitate–matrix interfaces and planar defects, and the development of strengthening models that account for the real particle shape. Future directions such as atomic-scale elemental mapping and computation, and the influence of particle shape on mechanical properties are discussed. With the combination of advanced characterization and computational tools, it is anticipated that much less time will be needed to develop the next generation of light alloys.
Soil erosion can pose a serious problem to environmental quality and sustainable development. On the Tibetan Plateau, soil erosion is one of the main challenges to regional ecological security. Our analysis investigates soil erosion and evaluates its economic value in alpine steppe, alpine meadow, alpine desert steppe and forest ecosystems on the Tibetan Plateau. Analysis was carried out from 1984 to 2013. The results show that the annual average potential soil erosion, practical soil erosion and soil conservation calculated by the Revised University Soil Loss Equation model were 2.19×109ta–1, 2.16×109ta–1 and 2.72×107ta–1, respectively. The economic value of retaining soil nutrients, reducing the formation of wasteland and the economic benefit of reducing sediment deposition were 1.98×108RMBa–1, 2.55×1012RMBa–1 and 7.44×104RMBa–1, respectively. From comparing different ecosystems, we found that the forest ecosystem had the greatest soil retention and economic values. We also found that the potential and actual soil erosion values were extremely high on the Tibetan Plateau. The study highlights that state and local policymakers must give greater emphasis to ecological protection in the future.
A bimetallic metal–organic frameworks (MOFs)-templated strategy was developed to fabricate mesoporous CdxZn1−xS polyhedrons with improved photocatalytic hydrogen evolution activity, and the formation mechanism of these mesoporous polyhedrons was discussed in detail. Incorporating Cd atoms, the Brunauer–Emmett–Teller surface areas of mesoporous CdxZn1−xS polyhedrons were significantly increased (271 m2/g), providing more exposed active sites compared with ZnS. In addition, suitable conduction band potential (< −0.55 eV) of the mesoporous CdxZn1−xS polyhedrons was also beneficial for the photocatalysis. Impressively, by the co-effects of mesoporous structure and modified conduction band, the mesoporous CdxZn1−xS polyhedrons exhibited better photocatalytic activity for hydrogen evolution than most reported photocatalysts without noble metals. The maximum hydrogen evolution rate of the CSZ3 reached 4.10 mmol/(h g) under visible-light irradiation and without any cocatalyst condition. This facile strategy for the construction of mesoporous CdxZn1−xS polyhedrons provided a deep insight to fabricate other metal sulfides for a variety of photochemical applications.
The seasonality of individual influenza subtypes/lineages and the association of influenza epidemics with meteorological factors in the tropics/subtropics have not been well understood. The impact of the 2009 H1N1 pandemic on the prevalence of seasonal influenza virus remains to be explored. Using wavelet analysis, the periodicities of A/H3N2, seasonal A/H1N1, A/H1N1pdm09, Victoria and Yamagata were identified, respectively, in Panzhihua during 2006–2015. As a subtropical city in southwestern China, Panzhihua is the first industrial city in the upper reaches of the Yangtze River. The relationship between influenza epidemics and local climatic variables was examined based on regression models. The temporal distribution of influenza subtypes/lineages during the pre-pandemic (2006–2009), pandemic (2009) and post-pandemic (2010–2015) years was described and compared. A total of 6892 respiratory specimens were collected and 737 influenza viruses were isolated. A/H3N2 showed an annual cycle with a peak in summer–autumn, while A/H1N1pdm09, Victoria and Yamagata exhibited an annual cycle with a peak in winter–spring. Regression analyses demonstrated that relative humidity was positively associated with A/H3N2 activity while negatively associated with Victoria activity. Higher prevalence of A/H1N1pdm09 and Yamagata was driven by lower absolute humidity. The role of weather conditions in regulating influenza epidemics could be complicated since the diverse viral transmission modes and mechanism. Differences in seasonality and different associations with meteorological factors by influenza subtypes/lineages should be considered in epidemiological studies in the tropics/subtropics. The development of subtype- and lineage-specific prevention and control measures is of significant importance.
We present a study of absolute and convective instabilities in electrohydrodynamic flow subjected to a Poiseuille flow (EHD-Poiseuille). The electric field is imposed on two infinite flat plates filled with a non-conducting dielectric fluid with unipolar ion injection. Mathematically, the dispersion relation of the linearised problem is studied based on the asymptotic response of an impulse disturbance imposed on the base EHD-Poiseuille flow. Transverse, longitudinal and oblique rolls are investigated to identify the saddle point satisfying the pinching condition in the corresponding complex wavenumber space. It is found that when the ratio of Coulomb force to viscous force increases, the transverse rolls can transit from convective instability to absolute instability. The ratio of hydrodynamic mobility to electric mobility, which exerts negligible effect on the linear stability criterion when the cross-flow is small, has significant influence on the convective–absolute instability transition, especially when the ratio is small. As we change the value of the mobility ratio, a saddle point shift phenomenon occurs in the case of transverse rolls. The unstable longitudinal rolls are convectively unstable as long as there is a cross-flow, a result which is deduced from a one-mode Galerkin approximation. Longitudinal rolls have a larger growth rate than transverse rolls except for a small cross-flow. Finally, regarding the oblique rolls, a numerical search for the saddle point simultaneously in the complex streamwise and transverse wavenumber spaces always yields an absolute transverse wavenumber of zero, implying that oblique rolls give way to transverse rolls when the flow is unstable.
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.
In inertial confinement fusion experiments that involve short-laser pulses such as fast ignition (FI), diagnosis of neutrons is usually very challenging because high-intensity γ rays generated by short-laser pulses would mask the much weaker neutron signal. In this paper, fast-response scintillators with low afterglow and gated microchannel plate photomultiplier tubes are combined to build neutron time-of-flight (nTOF) spectrometers for such experiments. Direct-drive implosion experiments of deuterium-gas-filled capsules were performed at the Shenguang-II Upgrade (SG-II-UP) laser facility to study the compressed fuel areal density (〈ρR〉) and evaluate the performance of such nTOF diagnostics. Two newly developed quenched liquid scintillator detectors and a gated ultrafast plastic scintillator detector were used to measure the secondary DT neutrons and primary DD neutrons, respectively. The secondary neutron signals were clearly discriminated from the γ rays from (n, γ) reactions, and the compressed fuel areal density obtained with the yield-ratio method agrees well with the simulations. Additionally, a small scintillator decay tail and a clear DD neutron signal were observed in an integrated FI experiment as a result of the low afterglow of the oxygen-quenched liquid scintillator.
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.
The purpose of the present meta-analysis was to evaluate the association between the inflammatory potential of diet, determined by the dietary inflammatory index (DII®) score, and depression.
Systematic review and meta-analysis.
A comprehensive literature search was conducted in PubMed, Web of Science and EMBASE databases up to August 2018. All observational studies that examined the association of the DII score with depression/depressive symptoms were included.
Four prospective cohorts and two cross-sectional studies enrolling a total of 49 584 subjects.
Overall, individuals in the highest DII v. the lowest DII category had a 23 % higher risk of depression (risk ratio (RR)=1·23; 95 % CI 1·12, 1·35). When stratified by study design, the pooled RR was 1·25 (95 % CI 1·12, 1·40) for the prospective cohort studies and 1·16 (95 % CI 0·96, 1·41) for the cross-sectional studies. Gender-specific analysis showed that this association was observed in women (RR=1·25; 95 % CI 1·09, 1·42) but was not statistically significant in men (RR=1·15; 95 % CI 0·83, 1·59).
The meta-analysis suggests that pro-inflammatory diet estimated by a higher DII score is independently associated with an increased risk of depression, particularly in women. However, more well-designed studies are needed to evaluate whether an anti-inflammatory diet can reduce the risk of depression.
The feature distinguishing typical angiosperms from gymnosperms is that their ovules are enclosed before pollination. Bennettitales were formerly related to angiosperms because of the flower-like organisation of the former's reproductive organs. There is little information on how the naked ovules of Bennettitales became enclosed in angiosperms because fossil evidence for such a transition, if it exists, has not been described. Here, we report a reproductive organ, Zhangwuia gen. nov., from the Middle Jurassic of Inner Mongolia, China. Like many Bennettitales, the arrangement of the foliar parts around the female part in Zhangwuia demonstrates a resemblance to typical angiosperm flowers. It is noteworthy that the ovule is secluded from the exterior space in Zhangwuia, therefore implying the existence of angio-ovuly. Although Bennettitales have been related to angiosperms for more than a hundred years, their way of ovule-enclosing was not previously revealed. The discovery of Zhangwuia prompts a rethinking of the relationship between Bennettitales and angiosperms, as well as of the origin of angiosperms.
Solution-processed metal oxide electronics on flexible substrates can enable applications from military to health care. Due to limited thermal budgets and mismatched coefficients of thermal expansion between oxides and substrates, achieving good performance in solution-processed oxide films remains a challenge. Additionally, the use of traditional photolithographic processes is incompatible with low-cost, high-throughput roll-to-roll processing. Here, we demonstrate solution-deposited oxide thin film transistors (TFTs) on a shape memory polymer substrate, which offers unique control of final device shape and modulus. The key enabling step is the exposure of the precursor film to UV-ozone through a shadow mask to perform patterning and photochemical conversion simultaneously. These TFTs exhibit mobility up to 160 cm2/(V s), subthreshold swing as low as 110 mV/dec, and threshold voltage between −2 and 0 V, while maintaining compatibility with a flexible form factor at processing temperatures below 250 °C.