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Common vetch (Vicia sativa) is an important forage and green manure crop that is widely cultivated around the world. However, the large number of subspecies and accessions of common vetch has made taxonomic research on this species difficult. Pollen morphology data can provide important evidence in the study of plant phylogeny. Therefore, in this research, light microscopy and scanning electron microscopy were used to observe seven morphological traits of pollens from 22 common vetch accessions, and residual maximum likelihood and pattern analysis was conducted. The results showed that the pollen grains of the 22 accessions were all monad pollen and the polar view revealed three-lobed circular and triangular shapes, while the equatorial view mainly revealed an oblate shape; only one accession showed an oblate spherical shape. All accessions were 3-zonocolporate and the colpus length extended close to the poles. The polar axis length was (19.39 ± 0.97)–(42.12 ± 0.76) μm and the equatorial axis length was (35.97 ± 1.27)–(45.25 ± 0.81) μm. We found that qualitative traits of pollen shape, aperture polar view and ornamentation were highly stable. Among them, polar axis length, equatorial axis length and colpus length and width had significant differences among the accessions. The ratios of the equatorial and polar axes had significant differences among the subspecies. This trait information could be used for the classification and identification of common vetch accessions and subspecies.
There have been reports on re-detectable positive nucleic acid tests for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in recovered coronavirus disease (COVID-19) patients. In this study, we look at the clinical characteristics, possible causes, pathogenesis, and infectivity of re-detectable positive patients and provide up-to-date information to public health policy planners and clinicians.
By consulting the latest research data and related progress data of re-detectable positive patients, this study addresses the implications that this special group brings to clinical work and disease prevention and control.
We discuss in detail the phenomenon of re-detectable positive nucleic acid tests for recovered patients. There are many possible causes of a re-detectable positive, but there is no 1 factor that can fully explain this phenomenon.
It can’t be completely ruled out that the re-detectable positive patients are infectious. We should be alert to these re-detectable positive patients becoming chronic virus carriers, and virus serological IgM and IgG antibody tests should be added before patient discharge. It is urgent to find a more powerful evidence-based and virological basis for the integrity of viral ribonucleic acid and the variation of viral virulence with time through cell experiments in vitro and animal experiments in vivo.
Rare earth elements (REE) in marine minerals have been widely used as proxies for the redox status of depositional and/or diagenetic environments. Phosphate nodules, which are thought to grow within decimetres below the sediment–water interface and to be able to scavenge REE from the ambient pore water, are potential archives of subtle changes in REE compositions. Whether their REE signals represent specific redox conditions or they can be used to track the overlying water chemistry is worth exploring. Through in situ laser ablation – inductively coupled plasma – mass spectrometry (LA-ICP-MS), we investigate the REE compositions of a drill-core-preserved phosphate nodule from the lower Cambrian Niutitang Formation in the Daotuo area, northeastern Guizhou Province, South China. REE distributions of the nodule show concentric layers with systematic decreases in Ce anomalies (Ce/Ce*) from the core to the rim. The lowest Ce/Ce* appears in the outer rim where REE concentrations are relatively high. These results are interpreted to reflect REE exchange with pore water at a very early stage or bathymetric variation during apatite precipitation. The origin of the shale-normalized middle REE (MREE) enrichment in our sample is less constrained. Possible driving factors include preferential MREE substitution for Ca in the apatite lattice, degradation of organic matter and deposition beneath a ferruginous zone. Although speculative, the last possibility is consistent with the chemically stratified model for early Cambrian oceans, in which dynamic fluctuations of the chemocline provided an ideal depositional context for phosphogenesis.
Affective temperaments have been considered antecedents of major depressive disorder (MDD). However, little is known about how the covariation between alterations in brain activity and distinct affective temperaments work collaboratively to contribute to MDD. Here, we focus on the insular cortex, a critical hub for the integration of subjective feelings, emotions, and motivations, to examine the neural correlates of affective temperaments and their relationship to depressive symptom dimensions.
Twenty-nine medication-free patients with MDD and 58 healthy controls underwent magnetic resonance imaging scanning and completed the Temperament Evaluation of Memphis, Pisa, Paris and San Diego (TEMPS). Patients also received assessments of the Hamilton Depression Rating Scale (HDRS). We used multivariate analyses of partial least squares regression and partial correlation analyses to explore the associations among the insular activity, affective temperaments, and depressive symptom dimensions.
A profile (linear combination) of increased fractional amplitude of low-frequency fluctuations (fALFF) of the anterior insular subregions (left dorsal agranular–dysgranular insula and right ventral agranuar insula) was positively associated with an affective-temperament (depressive, irritable, anxious, and less hyperthymic) profile. The covariation between the insula-fALFF profile and the affective-temperament profile was significantly correlated with the sleep disturbance dimension (especially the middle and late insomnia scores) in the medication-free MDD patients.
The resting-state spontaneous activity of the anterior insula and affective temperaments collaboratively contribute to sleep disturbances in medication-free MDD patients. The approach used in this study provides a practical way to explore the relationship of multivariate measures in investigating the etiology of mental disorders.
Three-dimensional graphene (3D-GN)/Cu/Fe3O4 composite support materials were synthesized by a modified chemical reduction method using graphene oxide precursor. A 3D-GN/Cu/Fe3O4 biosensor was prepared by coating the electrode with laccase. The electrochemical properties of the biosensor were investigated by cyclic voltammetry (CV) and differential pulse voltammetry using potassium ferricyanide, phosphate-buffered saline (PBS) solution, and bisphenol A (BPA) solution. The current response of 3D-GN/Cu/Fe3O4 biosensors presents a remarkable sensitivity based on CV. The linear range of BPA is 7.2–18 μM using differential pulse voltammetry in PBS solution (pH = 4.0). A linear fitting equation of the laccase biosensor was observed for the current response as a function of BPA concentration. The detection limit was decreased to 1.7 μM. The detection approach herein turns out to be highly sensitive, has a wide linear range, and exhibits excellent stability.
Monosized spherical Cu–20% Sn (wt%) alloy particles with diameter ranging from 70.6 to 334.0 μm were prepared by the pulsated orifice ejection method (termed “POEM”). Fully dense without pores and bulk inclusions, the cross-sectional micrographs of the spherical alloy particles indicate an even distribution of Cu and Sn. These spherical Cu–Sn alloy particles exhibit a good spherical shape and a narrow size distribution, suggesting that the liquid Cu–Sn alloy can completely break the balance between the surface tension and the liquid static pressure in the crucible micropores and accurately control the volume of the droplets. Furthermore, the cooling rate of spherical Cu–20% Sn alloy particles is estimated by a Newton’s cooling model. The cooling rate of the Cu–20% Sn alloy particle decreases gradually with the particle diameter increasing. Smaller particles have higher cooling rates and when the particle diameter is less than 70 μm, the cooling rate of particles can reach more than 3.3 × 104 K/s. The secondary dendrite arm spacing has strong dependence on particle diameter which increases gradually with the increase of particle diameter. The results demonstrate that POEM is an effective route for fabrication of high-quality monosized Cu–20% Sn alloy particles.
Although alterations in the dendritic spine density in the brain regions may play a role in the stress-induced depression-like phenotype, the precise mechanisms are unknown. The aim was to investigate the role of spine density in the brain regions after chronic social defeat stress (CSDS).
We examined dendritic spine density in the medial prefrontal cortex (mPFC), CA1, CA3, dentate gyrus (DG) of hippocampus, nucleus accumbens (NAc), and ventral tegmental area (VTA) of susceptible and resilient mice after CSDS.
Spine density in the prelimbic area of mPFC, CA3, and DG in the susceptible group, but not resilient group, was significantly lower than control group. In contrast, spine density in the NAc and VTA in the susceptible group, but not resilient group, was significantly higher than control group.
The results suggest that regional differences in spine density may contribute to resilience versus susceptibility in mice subjected to CSDS.
As the operating temperature of disk service was elevated from 650 °C to 700 °C, the creep properties urged to be paid attention. To investigate the creep properties of spray-formed low solvus, high refractory (LSHR) superalloy at about 700 °C, creep tests were conducted under seven different stress ranging from 690 MPa to 897 MPa. By means of creep curves and fracture microstructure observation, the creep behaviors and fracture mechanisms of spray-formed LSHR were analyzed. Stress exponent of the alloy was comparable to other disk superalloys such as Waspaloy and Inconel 718. It was interesting to find a transition in the creep behavior in two stress regimes. The contribution of grain boundary sliding in the low stress regime was greater than that in the higher stress. Under higher stress microcracks initiated along the intragranular slip bands because of strain concentration. The spray-forming LSHR exhibited a good creep resistance at low stress compared with other two superalloys by using Larson–Miller parameter, which was consistent with the transition of fracture behaviors.
Stable isotopic analysis of carbon and nitrogen in human and faunal remains has been widely used to reconstruct prehistoric diets and environmental changes. Isotopic analysis of plant remains allows for a more extensive consideration of paleodiets and can potentially provide information about the environment in which the crops were grown. This paper reports the results of δ13C and δ15N analyses performed on modern and charred archaeological foxtail millet samples collected from the western part of the Chinese Loess Plateau. The δ13C mean value of modern samples is lower than that of ancient samples. There is a significant difference between grain and leaf δ15N values. These results challenge the standard assumption in isotope studies that the nitrogen isotope signals of the different part of plants consumed by humans and animals are the same. The 3–5‰ difference between human and animal δ15N values is always regarded as an indicator of whether human diets contained considerable animal protein. The difference between grain and leaf δ15N values makes this assumption problematic in a foxtail millet-dominated society.
We report on the occurrence of sinter-hardening with concurrent improved plasticity in fine-grained Fe79.3Mo4.5P8.1C6.75B1.35 bulk alloys fabricated by spark plasma sintering (SPS) of metallic glass composite powder. When the sintering temperature is higher than the austenite transformation temperature, the as-fabricated bulk alloys are composed of expected wattle martensite plus Fe3P, Fe7C3, and Fe3Mo3C. Meanwhile, the martensite-containing bulk alloys exhibit increased hardness, fracture strength as well as concurrent improved plasticity. The fracture stress and strain of the martensite-containing bulk alloys are as high as 2573 MPa and 8.6%, respectively. The formation of the martensite microstructure is attributed to that high sintering temperature leads to the austenitization transformation and consequently formed austenite partially transforms into martensite under rapid cooling rate provided by SPS system. The results obtained provide insight into fabrication of iron alloys with good mechanical property by powder metallurgy.
Seed storage proteins (SSPs) are synthesized during development and the expression of their genes is under tight tissue-specific and temporal transcriptional regulation. In this review we summarize the current knowledge concerning the regulatory steps controlling SSP synthesis in Arabidopsis and cereals, which involves the interaction of cis regulatory elements with corresponding trans-acting factors. In some cases, the regulation of SSP genes requires the concerted action of multiple transcription factors (TFs). There is an evolutionary conservation between the prolamins (the main group of SSPs in many cereal grains) and a major group of dicot seed albumins; this relates to both the regulatory elements and the TFs that are functionally exchangeable between the monocot and dicot species.
The events resulting in compaction have an important influence on the processes related to blastocyst formation. To analyse the quality of the embryos obtained by somatic cell nuclear transfer (SCNT) in aspects different from previous studies, not only the number of blastomeres of cloned embryos during the initiation of compaction, but also the distribution of microvilli in cloned, normal, parthenogenetic, and tetraploid embryos before and after compaction was preliminarily investigated in mouse. Our results showed that during compaction the number of blastomeres in SCNT embryos was fewer than that in intracytoplasmic sperm injection (ICSI) embryos and, before compaction, there was a uniform distribution of microvilli over the blastomere surface, but microvilli became restricted to an apical region after compaction in the four types of embryos. We also reported here that the time course of compaction in SCNT embryos was about 3 h delayed compared with that in ICSI embryos, while there was no significant difference between SCNT and ICSI embryos when developed to the 4-cell stage. We concluded that: (i) the cleavage of blastomeres in cloned embryos was slow at least before compaction; (ii) the distribution of microvilli in cloned, normal, parthenogenetic, and tetraploid embryos was coherent before and after compaction; and (iii) the initiation of compaction in SCNT embryos was delayed compared with that of ICSI embryos.
We report an experimental study of the large-scale circulation (LSC) in a turbulent Rayleigh–Bénard convection cell with aspect ratio unity. The temperature-extrema-extraction (TEE) method for obtaining the dynamic information of the LSC is presented. With this method, the azimuthal angular positions of the hot ascending and cold descending flows along the sidewall are identified from the measured instantaneous azimuthal temperature profile. The motion of the LSC is then decomposed into two different modes based on these two angles: the azimuthal mode and the translational or sloshing mode that is perpendicular to the vertical circulation plane of the LSC. Comparing to the previous sinusoidal-fitting (SF) method, it is found that both the TEE and the SF methods give the same information about the azimuthal motion of the LSC, but the TEE method in addition can provide information about the sloshing motion of the LSC. The sloshing motion is found to oscillate time-periodically around the cell's central vertical axis with an amplitude being nearly independent of the turbulent intensity and to have a π/2 phase difference with the torsional mode. It is further found that the azimuthal angular positions of the hot ascending and cold descending flows oscillate out of phase with each other by π, which leads to the observations of the torsional mode when these two flows are near the top and the bottom plates, respectively, and of the sloshing mode when they are both near the mid-height plane. A direct velocity measurement further confirms the existence of the bulk sloshing mode of the flow field.
To identify the disease-causing gene for a large multi-generational Chinese family affected by familial hypertrophic cardiomyopathy (FHCM), genome-wide screening was carried out in a Chinese family with FHCM using micro-satellite markers, and linkage analysis was performed using the MLINK program. The disease locus was mapped to 1q32 in this family. Screening for a mutation in the cardiac troponin T (cTnT) gene was performed by a PCR and sequencing was done with an ABI Prism 3700 sequencer. A novel C→G transition located in the ninth exon of the cTnT gene, leading to a predicted amino acid residue change from Ile to Met at codon 90, was identified in all individuals with hypertrophic cardiomyopathy (HCM). The results presented here strongly suggest that Ile90Met, a novel mutation in the cTnT gene, is causative agent of HCM in this family.
Nanotubular structures in the B-C-N ceramic system represent an intriguing alternative to conventional carbon nanotubes.Because of the ability to widely vary the chemical composition of nanotubes within the B-C-N ternary phase diagram and to change the stacking of C-rich or BN-rich tubular shells in multiwalled structures, a wide horizon opens up for tuning nanostructure electrical properties.Pure carbon nanotubes are metals or narrow-bandgap semiconductors, depending on the helicity and diameter, whereas those of BN are insulators with a ∼5.0eV gap independent of these parameters.Thus, the relative B/C/N ratios and/or BN-rich and C-rich domain spatial arrangements, rather than tube helicity and diameter, are assumed to primarily determine the B-C-N nanotube electrical response.This characteristic is highly valuable for nanotechnology:while tube diameter and helicity are currently difficult to control, continuous doping of C with BN, or vice versa, proceeds relatively easily due to the isostructural nature of layered C and BN materials.In this article, recent progress in the synthesis, microscopic analysis, and electrical property measurements of a variety of compound nanotubes in the ceramic B-C-N system is documented and discussed.
We have compared the genetic diversity of 24 Chinese weak-winter, Swedish winter and spring Brassica napus accessions by inter-simple sequence repeats (ISSRs). Using cluster analysis (UPGMA) based on 125 polymorphism bands amplified with 20 primers, the 24 accessions were divided into three groups. Six Swedish winter lines and eight Chinese weak-winter lines were in group I and group II consisted of two Chinese weak-winter lines, Xiangyou15 and Bao81. The third group contained eight Swedish spring lines. Principal coordinates (PCO) analysis showed similar groupings to cluster analysis. Results from cluster analysis and PCO analysis showed very clearly that Chinese weak-winter, Swedish spring and winter accessions were distinguished from each other and Chinese weak-winter accessions in this study were genetically closer to Swedish winter accessions than to Swedish spring accessions. The Chinese weak-winter accessions had larger diversity than the Swedish spring or winter accessions. This study indicated that ISSR is a suitable and effective tool to evaluate genetic diversity among rapeseed germplasm.
Multiwalled B-C-N nanotubes of various morphologies and chemical compositions were synthesized by reacting C-based nanotube templates with boron oxide and nitrogen at 1573 K- 2173 K. The nanotubes were thoroughly analysed using a high-resolution field-emission 300 kV transmission electron microscope (TEM), an energy-filtered field-emission 300 kV electron microscope (Omega filter), an electron energy loss spectrometer and an energy dispersion X-ray detector. Transport and field emission properties of the nanotubes were studied using a low energy electron point source microscope and via in-situ measurements in TEM equipped with a scanning tunnelling microscope (STM) unit.
It is found on the KT-5C tokamak that an edge fluctuation can be
a pair of floating Langmuir-probe pins. This fluctuation propagates along
magnetic field, with its amplitude decreasing drastically when it is off
magnetic field line, which is similar to the results obtained from experiments
the TEXT tokamak. Moreover, our experimental observations indicate that
excited fluctuation propagates with the electron directional motion, and
mainly manifested in an electron density fluctuation. Physically, this
fluctuation could be considered as modulation of the external electric
electrons, and is carried by the electron directional motion wherever it
These results are in good agreement with the proposed ballistic model that
be derived by solving the linearized Vlasov equation.
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