In this work, a confined-doped fiber with the core/inner-cladding diameter of 40/250 μm and a relative doping ratio of 0.75 is fabricated through a modified chemical vapor deposition method combined with the chelate gas deposition technique, and subsequently applied in a tandem-pumped fiber amplifier for high-power operation and transverse mode instability (TMI) mitigation. Notably, the impacts of the seed laser power and mode purity are preliminarily investigated through comparative experiments. It is found that the TMI threshold could be significantly affected by the seed laser mode purity. The possible mechanism behind this phenomenon is proposed and revealed through comprehensive comparative experiments and theoretical analysis. Finally, a maximum output power of 7.49 kW is obtained with the beam quality factor of approximately 1.83, which is the highest output power ever reported in a forward tandem-pumped confined-doped fiber amplifier. This work could provide a good reference and practical solution to improve the TMI threshold and realize high-power high-brightness fiber lasers.

The selection of high-quality sperms is critical to intracytoplasmic sperm injection, which accounts for 70–80% of in vitro fertilization (IVF) treatments. So far, sperm screening is usually performed manually by clinicians. However, the performance of manual screening is limited in its objectivity, consistency, and efficiency. To overcome these limitations, we have developed a fast and noninvasive three-stage method to characterize morphology of freely swimming human sperms in bright-field microscopy images using deep learning models. Specifically, we use an object detection model to identify sperm heads, a classification model to select in-focus images, and a segmentation model to extract geometry of sperm heads and vacuoles. The models achieve an F1-score of 0.951 in sperm head detection, a z-position estimation error within ±1.5 μm in in-focus image selection, and a Dice score of 0.948 in sperm head segmentation, respectively. Customized lightweight architectures are used for the models to achieve real-time analysis of 200 frames per second. Comprehensive morphological parameters are calculated from sperm head geometry extracted by image segmentation. Overall, our method provides a reliable and efficient tool to assist clinicians in selecting high-quality sperms for successful IVF. It also demonstrates the effectiveness of deep learning in real-time analysis of live bright-field microscopy images.

The horse played a crucial role in China through the first millennium BC, used both for military advantage and, through incorporation into elite burials, to express social status. Details of how horses were integrated into mortuary contexts during the Qin Empire, however, are poorly understood. Here, the authors present new zooarchaeological data for 24 horses from an accessory pit in Qin Shihuang's mausoleum, indicating that the horses chosen were tall, adult males. These findings provide insights into the selection criteria for animals to be included in the emperor's tomb and invite consideration of questions concerning horse breeds, husbandry practices, and the military and symbolic importance of horses in early imperial China.

A Na-montmorillonite (Na-MMT) was activated with HNO3 (20 wt.%) solution at various temperatures and times to obtain acid-activated MMT (Acid-MMT). Zinc (4 wt.%) was supported on Acid-MMT via the impregnation method using Zn(NO3)2⋅6H2O as a precursor. The catalytic performance of the Zn/Acid-MMT for the aromatization of heptane was investigated. The amount and distribution of acidity of Acid-MMT, which could be adjusted by changing the acid activation time and temperature, significantly affected the heptane conversion and aromatics content. As a result, an efficient Zn/Acid-MMT catalyst for the aromatization reaction was obtained by optimizing the acid-treatment conditions of Na-MMT.

We aimed to describe the clinical features in coronavirus disease 2019 (COVID-19) cases. We studied 134 critically ill COVID-19 cases from 30 December 2019 to 20 February 2020 in an intensive care unit (ICU) at Wuhan Jinyintan Hospital. Demographics, underlying diseases, therapy strategies and test results were collected and analysed from patients on admission, admission to the ICU and 48 h before death. The non-survivors were older (65.46 (s.d. 9.74) vs. 46.45 (s.d. 11.09)) and were more likely to have underlying diseases. The blood group distribution of the COVID-19 cases differed from that of the Han population in Wuhan, with type A being 43.85%; type B, 26.92%; type AB, 10% and type O, 19.23%. Non-survivors tend to develop more severe lymphopaenia, with higher C-reactive protein, interleukin-6, procalcitonin, D-dimer levels and gradually increased with time. The clinical manifestations were non-specific. Compared with survivors, non-survivors more likely to have organ function injury, and to receive mechanical ventilation, either invasively or noninvasively. Multiple organ failure and secondary bacterial infection in the later period is worthy of attention.

Exosomes derived from hepatocellular carcinoma (HCC) cells are nanovesicles and are involved in the occurrence and development of HCC, they also serve as important carriers and drug targets of nanodrug delivery systems. The external shape and internal structure of exosomes are important indexes of identification, and isolated intact morphology is crucial to biological function integrity. However, given their susceptibility to various influencing factors, the external shape and internal structure of exosomes derived from HCC cells remain incompletely studied. In this study, exosomes purified from HCC cells were isolated at different centrifugation speeds and examined via multiple electron microscopy (EM) techniques. The results demonstrate that exosomes possess a nearly spherical shape and bilipid membranous vesicle with a concave cavity structure containing electron-dense and coated vesicles, suggesting the possible existence of subpopulations of exosomes with specific functions. The exosomes isolated at ultracentrifugation (UC) speed (≥110,000×g) presented irregular and diverse external morphologies, indicating the effect on the integrity of the exosomes. Transforming growth factor signaling bioactive substances (TGF-β1, S100A8, and S100A9) can be found in exosomes by performing Western blotting, showing that the internal content is associated with metastasis of HCC. These findings show that EMelectron microscopy and UC speed can affect exosome characteristics, including external shape, internal structure, and content of bioactive substances. The electron-dense and coated vesicles that had been discovered in exosomes might become new additional morphological features, which could help to improve the interpretation of experimental results and widen our understanding of exosome morphology.

It is well known that the energy for solar eruptions comes from magnetic fields in solar active regions. Magnetic energy storage and dissipation are regarded as important physical processes in the solar corona. With incomplete theoretical modeling for eruptions in the solar atmosphere, activity forecasting is mainly supported with statistical models. Solar observations with high temporal and spatial resolution continuously from space well describe the evolution of activities in the solar atmosphere, and combined with three dimensional reconstruction of solar magnetic fields, makes numerical short-term (within hours to days) solar activity forecasting possible. In the current report, we propose the erupting frequency and main attack direction of solar eruptions as new forecasts and present the prospects for numerical short-term solar activity forecasting based on the magnetic topological framework in solar active regions.

Water deficit is an environmental factor that constrains crops to express their ecophysiological potential and causes crop yield reduction. Eruca vesicaria has been reported to be one of the most drought-tolerant species in Cruciferae. In this study, polyethylene glycol-simulated drought tolerance was evaluated in one line of Brassica carinata, one line of Brassica napus and 249 Eruca lines based on the principal component analysis (PCA) and unweighted pair-group arithmetic average (UPGMA) cluster analysis. The PCA based on eight drought tolerance indices indicated that the first three components accounted for 85.46% of the total variation, with principal component (PC) 1 accounting for 43.89%, PC2 for 27.85% and PC3 for 13.73% of the total variation. The UPGMA cluster analysis indicated that B. napus cultivar Zhongshuang 9 and Eruca lines could be clustered into five major groups, with group 1 being, in general, drought sensitive, group 2 being slightly–medium drought tolerant, group 3 being drought tolerant, group 4 being highly drought sensitive and group 5 being highly drought tolerant. B. carinata cultivar XB1, as an outstander, showed high drought sensitivity. The UPGMA cluster dendrogram provides a good representation of the similarity matrix (r= 0.68). The drought-tolerant Eruca materials obtained in this study will be valuable for genetic improvement not only in Eruca itself, but also in Brassica crops since they are drought-tolerant lines from a drought-tolerant species.

The aim of this study was to evaluate the therapeutic effects of osteopontin neutralization treatment on schistosome-induced liver injury in BALB/C mice. We randomly divided 100 BALB/C mice into groups A, B, C, D and group E. Mice in all groups except group A were abdominally infected with schistosomal cercariae to induce a schistosomal hepatopathological model. Mice in group C, D and group E were respectively administered with praziquantel, praziquantel plus colchicine and praziquantel plus neutralizing osteopontin antibody. We extracted mouse liver tissues at 3 and 9 weeks after the ‘stool-eggs-positive’ day, observed liver histopathological changes by haematoxylin-eosin and Masson trichrome staining and detected the expression of osteopontin, alpha-smooth muscle actin (α-SMA) and transforming growth factor-beta (TGF-β1) by immunohistochemistry, RT-PCR and Western blot. We found that praziquantel plus neutralizing osteopontin antibody treatment significantly decreased the granuloma dimension, the percentage of collagen and the expression of osteopontin, α-SMA and TGF-β1 compared to praziquantel plus colchicine treatment in both the acute and chronic stage of schistosomal liver damage (P<0·05). So we believe that the combined regimen of osteopontin immunoneutralization and anti-helminthic treatment can reduce the granulomatous response and liver fibrosis during the schistosomal hepatopathologic course.

This study describes the fabrication of hybrid micro- and nanostructures of semiconductor nanocrystals arranged in microscopic lines inside of a borosilicate glass doped with CdSxSe1-x. This was performed using a two step process of (1) ultrafast laser modification and (2) heat treatment. The glass was photomodified using focused sub-picosecond infra-red pulses with 1 MHz repetition rate to create linear domains with local compositional variations. Heat treating the sample at temperatures near glass transition preferentially precipitated semiconductor in the modified regions, as evidenced by confocal fluorescence microscopy. The optical properties of the precipitated nanocrystals varied with heat treatment duration.

Genetic diversity and genetic variation of 240 adult plants of four tea populations in Hunan – Camellia sinensis var. sinensis, C. sinensis var. assamica cv. Duntsa, C. ptilophylla and C. sinensis var. assamica cv. Jianghua – were studied by rapid amplification of polymorphic DNA (RAPD) markers. The results showed 226 loci using 21 random primers (10 bp), of which 201 (88.9%) were polymorphic. The genetic diversity analysis indicated that Shannon's index was 0.43; 74.7% of which was within-population genetic diversity while 25.3% was among-population variation. The gene diversity indexes of total populations (HT), within populations (HS) and among populations (HST) were, respectively, 0.37, 0.28 and 0.09. The coefficient of gene differentiation (GST) among populations was 0.23, indicating a 76.7% variation within populations and 23.3% among populations. These results displayed a rich within-population genetic variation, as in Shannon's diversity index. Interpopulation gene flow (Nm) was 0.74, which indicates the limited genetic exchange between populations.

The S-layer protein CTC surface display system of Bacillus thuringiensis was used to test the possibility of displaying H5N1 Avian influenza virus (AIV) haemagglutinin HA1 on the cell surface of B. thuringiensis. Two recombinant plasmids, pCTC-HA1P and pCSHA1P, were constructed by replacing the central part below the surface anchor sequence slh of S-layer protein gene ctc with part ha1 gene (ha1p). pCTC-HA1P harboured the fusion gene ctc-ha1p and pCSHA1P the fusion gene csa-ctc-ha1p, csa representing the csaAB operon (very important in anchoring S-layer protein on the bacterial cell surface). Two recombinant B. thuringiensis strains were constructed by electrotransferring recombinant plasmids to B. thuringiensis plasmid-free derivative strain BMB171. Strains obtained were CH (bearing pCSHA1P) and BCCH (bearing pCTC-HA1P as well as the csaAB operon-carrying plasmid pMIL-CSA). The vegetative cells of CH and BCCH were used as antigens in haemagglutination (HA) and haemagglutination inhibition (HI) assays. HA assay showed recombinant HA1 proteins successfully displayed on the cell surface of CH and BCCH. HI assay showed that these recombinant HA1 proteins were specific to standard positive HI (haemagglutination inhibition test) serum of subtype H5 AIV. After immunization of mice with vegetative cells, both CH and BCCH elicited a humoral response to HA1 and exhibited immunogenicity as indicated by enzyme-linked immunosorbent assay (ELISA). ELISA also showed that CH exhibited a higher immunogenicity than BCCH. The strategy developed in this study suggests the possibility of generating a heat-stable and oral veterinary vaccine against AIV with the B. thuringiensis S-layer protein CTC surface display system.

The Chinese giant salamander Andrias davidianus is the largest living amphibian. Most wild populations are threatened and some are already extinct. The Chinese government has declared the species a Class II Protected Species, and it is listed as Critically Endangered in the Chinese Red Book of Amphibians and Reptiles and as Data Deficient on the IUCN Red List. Populations of the species have declined sharply in both range and number since the 1950s because of habitat loss and fragmentation, and hunting for the commercial luxury food trade. Remaining populations appear to be distributed in 12 areas across 17 provinces in the mountainous areas of the middle Yangtze, Yellow and Pearl Rivers. Since the 1980s, 14 nature reserves, with a total area of more than 355,000 ha, have been established for the conservation of the Chinese giant salamander. We carried out habitat and questionnaire surveys for the species in 13 locations, and based on the results and on the little amount of published information, most of it in Chinese, we assess the current status of the species and make recommendations for its conservation management. Conservation of the Chinese giant salamander should be given a high priority and considered an important part of wetland management.