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Cinnamomum chago is a woody species of the family Lauraceae endemic to Yunnan province, China, previously known from only one location, and categorized as a Plant Species with Extremely Small Population. We surveyed to determine the distribution and population size of C. chago, characterize its habitat, identify any threats, assess its conservation status, and provide guidelines for its management and conservation. During 2014–2017 we found only 64 mature C. chago, in five locations. These small, fragmented populations occur along Lancang River in Dali Prefecture at altitudes of 2,200–2,400 m. The species' extent of occurrence is c. 923 km2, with an area of occupancy of c. 60 km2. The habitat of the species has been degraded by expansion of pastoral activities and deforestation. We recommend categorization of C. chago as Endangered on the IUCN Red List, prevention of the collection of seeds and wood of the species, protection and monitoring, and ex situ propagation for future reintroductions.
Magnetic iron oxide nanoparticles (MIONPs) are particularly attractive in biosensor, antibacterial activity, targeted drug delivery, cell separation, magnetic resonance imaging tumor magnetic hyperthermia, and so on because of their particular properties including superparamagnetic behavior, low toxicity, biocompatibility, etc. Although many methods had been developed to produce MIONPs, some challenges such as severe agglomeration, serious oxidation, and irregular size are still faced in the synthesis of MIONPs. Thus, various strategies had been developed for the surface modification of MIONPs to improve the characteristics of them and obtain multifunctional MIONPs, which will widen the applicational scopes of them. Therefore, the processes, mechanisms, advances, advantages, and disadvantages of six main approaches for the synthesis of MIONPs; surface modification of MIONPs with inorganic materials, organic molecules, and polymer molecules; applications of MIONPs or modified MIONPs; the technical challenges of synthesizing MIONPs; and their limitations in biomedical applications were described in this review to provide the theoretical and technological guidance for their future applications.
Astrophysical collisionless shocks are amazing phenomena in space and astrophysical plasmas, where supersonic flows generate electromagnetic fields through instabilities and particles can be accelerated to high energy cosmic rays. Until now, understanding these micro-processes is still a challenge despite rich astrophysical observation data have been obtained. Laboratory astrophysics, a new route to study the astrophysics, allows us to investigate them at similar extreme physical conditions in laboratory. Here we will review the recent progress of the collisionless shock experiments performed at SG-II laser facility in China. The evolution of the electrostatic shocks and Weibel-type/filamentation instabilities are observed. Inspired by the configurations of the counter-streaming plasma flows, we also carry out a novel plasma collider to generate energetic neutrons relevant to the astrophysical nuclear reactions.
The accuracy and fault tolerance of filters are directly affected by the filter architecture and algorithm, thus influencing navigation performance. The chi square detection used in the conventional reset federated filter is not sensitive to soft faults, and it is easy to cause the health subsystem to be polluted through information sharing. It is a challenge to design an adaptive reset federated filter to improve the performance of the navigation system. Therefore, taking the Strapdown Inertial Navigation System/Global Positioning System/Celestial Navigation System/Synthetic Aperture Radar (SINS/GPS/CNS/SAR) integrated navigation system as an example, an adaptive federated filter architecture for vector-formed information sharing without a fault isolation module is designed in this paper. The proposed method uses the two-state chi square detection algorithm to calculate the parameters corresponding to each state, making the state with higher accuracy obtain a greater information distribution coefficient. In addition, according to the value of vector-formed information sharing, an adaptive coefficient of measurement noise is designed. This improves the adaptability of the navigation system to soft faults. Simulation results show that the accuracy of the proposed algorithm has the same performance compared with the conventional method under normal circumstances. When the sensor has a soft fault, the adaptive federated filter algorithm proposed in this paper can adaptively adjust the distribution coefficients, eliminate the influence of the fault information and improve the precision of the navigation system. The approach described in this paper can be used in multi-sensor integrated navigation. It will have better performance in engineering applications.
Field bindweed, a member of the Convolvulaceae family, is a problematic perennial weed in cotton fields and orchards in northwest China. The species exhibits strong seed dormancy, causing delayed germination. A clear understanding of the mechanisms involved in alleviating seed dormancy is important for effective plant propagation and successful management of field bindweed. Experiments were conducted to investigate seed germination and radicle growth of field bindweed by breaking seed dormancy using mechanical scarification, sulfuric acid, hot-water scarification, cold stratification, and chemical treatment. Chemical treatments (gibberellic acid or potassium nitrate) had no effect on breaking seed dormancy, whereas mechanical scarification (sandpaper and blade) resulted in 92% to 98% seed germination, indicating that seed dormancy of field bindweed was mainly due to the presence of a hard seed coat. Seeds pretreated with 80% sulfuric acid for 15 to 60 min or 98% sulfuric acid for 15 to 30 min had germination rates above 80%, and soaking seeds in 70 C water for 4 to 16 min or in boiling water for 5 to 20s were effective in breaking seed dormancy but had no effect on the radicle growth of field bindweed. Cold stratification at 5 C for 2 to 8wk partially accelerated seed dormancy release, resulting in 53% to 67% seed germination. Results indicated that field bindweed could potentially form a persistent soil seed bank with physically dormant seed; therefore, strategies for eliminating seed production should be adopted.
In this paper, a triple-wideband bandpass filter (BPF) with controllable bandwidths based on two multi-mode stub-loaded resonators (MMSLRs) and a triple-mode resonator is presented. The MMSLR is loaded with two identical folded open-ended stubs and a T-shaped stub. Each passband of the tri-band BPF is formed by four resonant modes, which provide sufficient bandwidths to meet various application requirement. By adjusting the lengths of open-ended stubs, three passband bandwidths can be controlled individually. The center frequencies of the triple-wideband BPF are allocated at 2.7, 3.67, and 5.44 GHz, with the 3 dB fractional bandwidths (FBWs) of 20.1, 14.7, and 26.3%. Among the three passbands, the highest one covers the 5 G WiFi band (5.15–5.85 GHz). The measured results of the proposed filter exhibit excellent agreement with simulated results.
We present laboratory measurement and theoretical analysis of silicon K-shell lines in plasmas produced by Shenguang II laser facility, and discuss the application of line ratios to diagnose the electron density and temperature of laser plasmas. Two types of shots were carried out to interpret silicon plasma spectra under two conditions, and the spectra from 6.6 Å to 6.85 Å were measured. The radiative-collisional code based on the flexible atomic code (RCF) is used to identify the lines, and it also well simulates the experimental spectra. Satellite lines, which are populated by dielectron capture and large radiative decay rate, influence the spectrum profile significantly. Because of the blending of lines, the traditional
value are not applicable in diagnosing electron temperature and density of plasma. We take the contribution of satellite lines into the calculation of line ratios of He-
lines, and discuss their relations with the electron temperature and density.
Ethanolamine (Etn) contained in milk is the base constituent of phosphatidylethanolamine and is required for the proliferation of intestinal epithelial cells and bacteria, which is important for maintenance of the gut microbiome and intestinal development. The present study investigated the effect of Etn on intestinal function and microbiome using 21-d-old Sprague–Dawley rats treated with 0, 250, 500 and 1000 μm Etn in drinking water for 2 weeks immediately after weaning. Growth performance, intestinal morphology, antioxidant capacity and mucosal immunity, as well as gut microbiota community composition, were evaluated. Metagenomic prediction and metabolic phenotype analysis based on 16S RNA sequencing were also carried out to assess changes in metabolic functions. We found that weaned rats administered 500 μm Etn enhanced mucosal antioxidant capacity, as evidenced by higher superoxide dismutase and glutathione peroxidase levels in the jejunum (P<0·05) compared with those in the control group. Predominant microbes including Bacteroidetes, Proteobacteria, Elusimicrobia and Tenericutes were altered by different levels of Etn compared with the control group. An Etn concentration of 500 µm shifted colonic microbial metabolic functions that are in favour of lipid- and sugar-related metabolism and biosynthesis. Etn also altered the metabolic phenotypes such as anaerobic microbial counts, and oxidative stress tolerance at over 250 µm. This is the first report for a role of Etn in modifying gut microbiota and intestinal functions. Our findings highlighted the important role of Etn in shaping gut microbial community and promotes intestinal functions, which may provide a better insight of breast-feeding to infant’s gut health.
The linear angular dispersion of a self-diffraction (SD) pulse, from a femtosecond laser pulse cleaning device, is compensated for by the use of a single prism. More than
first-order SD pulse has a contrast of
, which is about five orders of magnitude improvement from the input fundamental pulse. The wings of the distribution away from the main pulse in
ps are cleaned with a contrast improvement of about
, which verifies the pulse cleaning ability of the SD process.
The characteristics and mechanism for unsteady shock train motions were experimentally studied in a constant-area rectangular duct. High-speed Schlieren techniques and high-frequency pressure measurements were utilized in this research. The results show that the shock train undergoes periodical motions in response to downstream periodical excitations. The mechanism for unsteady shock train motions is that the shock train keeps changing its moving speed to change the relative Mach number ahead of shock train to match the varying back-pressure condition. It can be found that the unsteady shock train motion can be predicted well with a theoretical model, which is based on this mechanism. A correlation between the amplitude of shock train motions and some flow parameters was illustrated using an analytical equation, which was confirmed by the experimental results.
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.
In this paper, a dual-wideband bandpass filter (BPF) with independently controllable center frequencies (CFs) and wide stopband suppression is presented using a new quintuple-mode resonator (QMR). By applying the classical odd-/even-mode analysis method, the resonant characteristics of the new QMR have been analyzed. It shows that five modes can be excited, and two of them can be employed to form the lower passband, while the other three modes contribute to the higher passband. For verification, a dual-wideband BPF using the new QMR is designed, fabricated, and tested. Experimental results show that the CFs of the dual-wideband BPF centered at 2.96 GHz and 5.695 GHz with 3 dB fractional bandwidths of 27.7 and 23.4%, respectively. In addition, 20-dB suppression in upper-stopband ranges from 2.23 to 4.04f0, where f0 is the center frequency of the first passband. The measurement results are in good agreement with the prediction results.
A facile synthesis procedure of nitrogen-self-doped porous carbon (NPC) derived from abundant natural biological materials has been presented. The pyrolysis temperature and the weight ratio of Co3O4 to carbon play a key role in determining microscopic structure and electrochemical performances of the final materials. The ordered mesostructures with nanopores in the channel walls provided support for immobilization of well-dispersed Co3O4 nanoparticles. They also served as a highly conductive substrate for effectively alleviating severe particle aggregation during the charge/discharge processes, which prevented capacity fading from deteriorated electric contact between the components. Taking advantage of the interconnected porous structures and high specific surface area (1799 m2/g) of carbon substrate, the Co3O4/NPC composite as anode in lithium-ion battery delivers a stable reversible capacity of 903 mA h/g after 400 cycles. It is expected that by loading other electrode active materials on such carbon material, the manufacture of the promising anode materials with excellent cycle stability is highly possible.
Polymannuronic acid (PM), one of numerous alginates isolated from brown seaweeds, is known to possess antioxidant activities. In this study, we examined its potential role in reducing body weight gain and attenuating inflammation induced by a high-fat and high-sucrose diet (HFD) as well as its effect on modulating the gut microbiome in mice. A 30-d PM treatment significantly reduced the diet-induced body weight gain and blood TAG levels (P<0·05) and improved glucose tolerance in male C57BL/6J mice. PM decreased lipopolysaccharides in blood and ameliorated local inflammation in the colon and the epididymal adipose tissue. Compared with low-fat and low-sucrose diet (LFD), HFD significantly reduced the mean number of species-level operational taxonomic units (OTU) per sample as well as species richness (P<0·05) but did not appear to affect other microbial diversity indices. Moreover, compared with LFD, HFD altered the abundance of approximately 23 % of the OTU detected (log10 linear discriminant analysis (LDA) score>2·0). PM also had a profound impact on the microbial composition in the gut microbiome and resulted in a distinct microbiome structure. For example, PM significantly increased the abundance of a probiotic bacterium, Lactobacillus reuteri (log10 LDA score>2·0). Together, our results suggest that PM may exert its immunoregulatory effects by enhancing proliferation of several species with probiotic activities while repressing the abundance of the microbial taxa that harbor potential pathogens. Our findings should facilitate mechanistic studies on PM as a potential bioactive compound to alleviate obesity and the metabolic syndrome.
X-ray powder diffraction data, unit-cell parameters, and space group for alogliptin benzoate, C18H21N5O2·C7H6O2, are reported [a = 28.8260(8) Å, b = 9.9654(4) Å, c = 8.1477(8) Å, α = 90, β = 90, γ = 90°, unit-cell volume V = 2340.57 Å3, Z = 4, ρcal = 1.3097 g cm−3, and space group P212121]. All measured lines were indexed and are consistent with the P212121 space group, No detectable impurities were observed.
The TiO2 hollow spheres (TiO2HS) were successfully prepared by a hydrothermal method and added to Vulcan XC-72 carbon black as the support materials for Pd nanoparticles. A facile approach to promote ethylene glycol (EG) electrooxidation in alkaline medium was carried out by the PdBi/TiO2HS-C catalyst. The results show that Pd and Bi nanoparticles are uniformly dispersed on the surface of carbon-doped TiO2 hollow spheres, the appropriate amount of Bi modification into Pd/TiO2HS-C catalyst can enhance remarkably the electrocatalytic activity for EG oxidation, in which the PdBi/TiO2HS-C (Pd:Bi = 1:0.1) catalyst exhibits excellent stability. The high electrochemical performance is attributed to the unique structure and high surface area of the TiO2HS, metal nanoparticles uniform distribution, the electronic effect between Pd and Bi as well as the bifunctional effect between metal nanoparticles and the support TiO2HS-C. The results obtained are significant for the development of new Pd-based TiO2HS-C electrocatalysts for alcohol fuel cells.
In a waist-worn Pedestrian Navigation System (PNS) based on Dead-Reckoning (DR), heading drift caused by Micro-Electro-Mechanical System (MEMS) gyro bias is an essential factor affecting DR accuracy. Considering the characteristics of pedestrian navigation and the poor bias repeatability of MEMS gyros, this paper presents a standing calibration method for MEMS gyro bias. The current gyro biases for each boot can be calibrated accurately in the initial stage before walking. Since the attitude angles calculated by the output data from magnetic sensor and accelerometers do not drift, this paper applies the reverse algorithm of attitude updating to calculate the angular velocities of human motion. Then the gyro biases at each moment can be acquired by subtraction operation between the measured angular velocities from gyros and the calculated angular velocities of human motion. Finally, in order to restrain the random error caused by sensor noise, the calculated biases in the initial stage are smoothed, and consequently the optimal estimate of current gyro biases after each boot can be obtained. Still and dynamic turntable experiments and a walking experiment are performed to compare and analyse the proposed method and the Zero Angular Rate Update (ZARU) method. Experimental results show that the proposed method can also calibrate the gyro bias accurately in the case of body swaying.
X-ray powder diffraction data, unit-cell parameters, and space group for deferasirox, C21H15N3O4, are reported [a = 8.821(7) Å, b = 26.798(2) Å, c = 7.540(4) Å, α = 90°, β = 94.655(2)°, γ = 90°, unit-cell volume V = 1776.7(3) Å3, Z = 4, ρcal = 1.396 g cm−3, and space group P21/c]. All measured lines were indexed and are consistent with the P21/c space group. No detectable impurity was observed.
An ancient pottery workshop belonging to the Han Dynasty was excavated in Caoxie village, Hepu County. Caoxie village is an important archaeological site in Hepu County, Beihai City, in south China's Guangxi Zhuang Autonomous Region. It is believed that Hepu County was the oldest departure point on the ancient maritime trading route during the Han Dynasty (206 BC to AD 220) due to the ideal natural geographical conditions and the existence of a large number of Han tombs. Radiocarbon measurements on wood and charcoal samples from the Caoxie village site were performed at the Peking University AMS facility (PKU-AMS), Beijing, and the Centre for Isotopic Research for Cultural and Environmental Heritage (CIRCE) at Naples Second University, Italy. Calibrated ages were obtained with code CALIB 5 (Stuiver and Reimer 1993). The results of these measurements are presented and the related chronology is discussed.