Formation of electron depletion layer and parallel electric field in the separatrix region of anti-parallel magnetic reconnection

It is generally accepted that during collisionless magnetic reconnection, electrons flow toward the X line in the separatrix region, and then an electron depletion layer is formed.In this paper, with two-dimensional(2 D) particle-in-cell(PIC)simulation, we investigate the characteristics of the separatrix region during magnetic reconnection.In addition to the electron depletion layer, we find that there still exists an electric field parallel to the magnetic field in the separatrix region.Because a reduced ion-to-electron mass ratio and light speed are usually used in PIC simulation models, we also change these parameters to analyze the characteristics of the separatrix region.It is found that the increase in the ion-to-electron mass ratio makes the electron depletion layer and the parallel electric field more obvious, while the influence of light speed is less pronounced.

Identifying anomalous Floquet edge modes via bulk-edge correspondence

Floquet engineering appears as a new protocol for designing topological states of matter,and features anomalous edge modes pinned at quasi-energy π/T with vanished topological index.We propose how to predict the anomalous edge modes via the bulk Hamiltonian in frequency space,and use Zak phase to quantitatively index the topological properties.The above methods are clarified by the example of time periodic Kitaev chain with chemical potential of harmonic driving and pulse driving,and topological phase transitions are manifested at different driving frequencies.

Electron acceleration during magnetic islands coalescence and division process in a guide field reconnection

The magnetic merging process related to pairwise magnetic islands coalescence is investigated by two-dimensional particle-in-cell simulations with a guide field.Owing to the force of attraction between parallel currents within the initial magnetic islands,the magnetic islands begin to approach each other and merge into one big island.We find that this newly formed island is unstable and can be divided into two small magnetic islands spontaneously.Lastly,these two small islands merge again.We follow the time evolution of this process,in which the contributions of three mechanisms of electron acceleration at different stages,including the Fermi,parallel electric field,and betatron mechanisms,are studied with the guide center theory.

Serological Investigation into the Infected Genotypes of Patients with Japanese Encephalitis in the Coastal Provinces of China

Objective Genotypes(G)1,3,and 5 of the Japanese encephalitis virus(JEV)have been isolated in China,but the dominant genotype circulating in Chinese coastal areas remains unknown.We searched for G5 JEV-infected cases and attempted to elucidate which JEV genotype was most closely related to human Japanese encephalitis(JE)in the coastal provinces of China.Methods In this study,we collected serum specimens from patients with JE in three coastal provinces of China(Guangdong,Zhejiang,and Shandong)from 2018 to 2020 and conducted JEV cross-neutralization tests against G1,G3,and G5.Results Acute serum specimens from clinically reported JE cases were obtained for laboratory confirmation from hospitals in Shandong(92 patients),Zhejiang(192 patients),and Guangdong(77 patients),China,from 2018 to 2020.Seventy of the 361 serum specimens were laboratory-confirmed to be infected with JEV.Two cases were confirmed to be infected with G1 JEV,32 with G3 JEV,and two with G5 JEV.Conclusion G3 was the primary infection genotype among JE cases with a definite infection genotype,and the infection caused by G5 JEV was confirmed serologically in China.

Insight-HXMT observations of the first binary neutron star merger GW170817

Finding the electromagnetic(EM) counterpart of binary compact star merger, especially the binary neutron star(BNS) merger,is critically important for gravitational wave(GW) astronomy, cosmology and fundamental physics. On Aug. 17, 2017,Advanced LIGO and Fermi/GBM independently triggered the first BNS merger, GW170817, and its high energy EM counterpart,GRB 170817 A, respectively, resulting in a global observation campaign covering gamma-ray, X-ray, UV, optical, IR, radio as well as neutrinos. The High Energy X-ray telescope(HE) onboard Insight-HXMT(Hard X-ray Modulation Telescope) is the unique high-energy gamma-ray telescope that monitored the entire GW localization area and especially the optical counterpart(SSS17 a/AT2017 gfo) with very large collection area(~1000 cm^2) and microsecond time resolution in 0.2-5 MeV. In addition,Insight-HXMT quickly implemented a Target of Opportunity(ToO) observation to scan the GW localization area for potential X-ray emission from the GW source. Although Insight-HXMT did not detect any significant high energy(0.2-5 MeV) radiation from GW170817, its observation helped to confirm the unexpected weak and soft nature of GRB 170817 A. Meanwhile,Insight-HXMT/HE provides one of the most stringent constraints(~10^(-7) to 10^(-6) erg/cm^2/s) for both GRB170817 A and any other possible precursor or extended emissions in 0.2-5 MeV, which help us to better understand the properties of EM radiation from this BNS merger. Therefore the observation of Insight-HXMT constitutes an important chapter in the full context of multi-wavelength and multi-messenger observation of this historical GW event.

Overview to the Hard X-ray Modulation Telescope (Insight-HXMT) Satellite

As China’s first X-ray astronomical satellite, the Hard X-ray Modulation Telescope (HXMT), which was dubbed as Insight-HXMT after the launch on June 15, 2017, is a wide-band(1-250 ke V) slat-collimator-based X-ray astronomy satellite with the capability of all-sky monitoring in 0.2-3 Me V. It was designed to perform pointing, scanning and gamma-ray burst(GRB)observations and, based on the Direct Demodulation Method (DDM), the image of the scanned sky region can be reconstructed.Here we give an overview of the mission and its progresses, including payload, core sciences, ground calibration/facility, ground segment, data archive, software, in-orbit performance, calibration, background model, observations and some preliminary results.

ZIKA virus isolated from mosquitoes:a field and laboratory investigation in China,2016

A field investigation of arboviruses was conducted in Dejiang, Guizhou Province in the summer of 2016. A total of 8,795 mosquitoes, belonging to four species of three genera, and 1,300 midges were collected. The mosquito samples were identified on site according to their morphology, and the pooled samples were ground and centrifuged in the laboratory. The supernatant was incubated with mosquito tissue culture cells(C6/36) and mammalian cells(BHK-21) for virus isolation. The results indicated that 40%(3,540/8,795) were Anopheles sinensis, 30%(2,700/8,795) were Culex pipiens quinquefasciatus, and 29%(2,530/8,795)were Armigeres subbalbeatus. Furthermore, a total of eight virus isolates were obtained, and genome sequencing revealed two Zika viruses(ZIKVs) isolated from Culex pipiens quinquefasciatus and Armigeres subbalbeatus, respectively; three Japanese encephalitis viruses(JEVs) isolated from Culex pipiens quinquefasciatus; two Banna viruses(BAVs) isolated from Culex pipiens quinquefasciatus and Anopheles sinensis, respectively; and one densovirus(DNV) isolated from Culex pipiens quinquefasciatus.The ZIKVs isolated from the Culex pipiens quinquefasciatus and Armigeres subbalbeatus mosquitoes represent the first ZIKV isolates in China's Mainland. This discovery presents new challenges for the prevention and control of ZIKV in China, and prompts international cooperation on this global issue.

The High Energy X-ray telescope (HE) onboard the Insight-HXMT astronomy satellite

The Insight-Hard X-ray Modulation Telescope(Insight-HXMT) is a broadband X-ray and γ-ray(1-3000 ke V) astronomy satellite. One of its three main telescopes is the High Energy X-ray telescope(HE). The main detector plane of HE comprises 18 Na I(Tl)/Cs I(Na) phoswich detectors, where Na I(Tl) is used as the primary detector to measure ~ 20-250 ke V photons incident from the field of view(FOV) defined by collimators, and Cs I(Na) is used as the active shielding detector to Na I(Tl) by pulse shape discrimination. Additionally, Cs I(Na) is used as an omnidirectional γ-ray monitor. The HE collimators have a diverse FOV,i.e. 1.1°×5.7°(15 units), 5.7°×5.7°(2 units), and blocked(1 unit). Therefore, the combined FOV of HE is approximately5.7°×5.7°. Each HE detector has a diameter of 190 mm resulting in a total geometrical area of approximately 5100 cm2, and the energy resolution is ~15% at 60 ke V. For each recorded X-ray event by HE, the timing accuracy is less than 10 μs and the deadtime is less than 10 μs. HE is used for observing spectra and temporal variability of X-ray sources in the 20-250 ke V band either by pointing observations for known sources or scanning observations to unveil new sources. Additionally, HE is used for monitoring the γ-ray burst in 0.2-3 Me V band. This paper not only presents the design and performance of HE instruments but also reports results of the on-ground calibration experiments.

Genome sequencing and phylogenetic analysis of Banna virus(genus Seadornavirus,family Reoviridae)isolated from Culicoides

In an investigation of blood-sucking insects and arboviruses, a virus(YN12243) was isolated from Culicoides samples collected in the Sino-Burmese border region of Yunnan Province, China. The virus caused cytopathic effect(CPE) in C6/36 cells and passaged stably. Polyacrylamide gel analysis showed that the genome of YN12243 was composed of 12 segments of double-stranded RNA(dsRNA), with a distribution pattern of 6-6. The nucleotide and amino acid sequences of the coding region(1.12 segments) were17,803 bp and 5,925 amino acids in length, respectively. The phylogenetic analysis of VP1 protein(RdRp) revealed that YN12243 belonged to genus Seadornavirus of family Reoviridae, and further analysis indicated that YN12243 belongs to the Banna virus(BAV) genotype A2. Additionally, YN12243 was located in the same evolutionary cluster as BAV strains isolated from different mosquito species, suggesting that the BAV isolated from Culicoides does not have species barriers. These results indicate that Culicoides can also be a vector for BAV. In view of the hematophagous habits of Culicoides on cattle, horses, deer, and other large animals, as well as the possibility of spreading and causing a variety of animal arboviral diseases, it is important to improve infection detection and monitor the BAV in large livestock.

Nuclear translocation of OsMFT1 that is impeded by OsFTIP1 promotes drought toleranee in rice

Drought is the leading environmental threat affecting crop productivity,and plants have evolved a series of mechanisms to adapt to drought stress.The FT-interacting proteins(FTIPs)and phosphatidylethanola mine.binding proteins(PEBPs)play key roles in developmental processes,whereas their roles in the regulation of stress response are still largely unknown.Here,we report that OsFTIP1 negatively regulates drought response in rice.We showed that OsFTIP1 interacts with rice MOTHER OF FT AND TFL1(OsMFT1),a PEBP that promotes rice tolerance to drought treatment.Further studies discovered that OsMFT1 interacts with two key drought-related transcription factors,OsbZIP66 and OsMYB26,regulating their binding capacity on drought-related genes and thereby enhancing drought toleranee in rice.Interestingly,we found that OsFTIP1 impedes the nucleocytoplasmic translocation of OsMFT1,implying that dynamic modulation of drought-responsive genes by the OsMFT1-OsMYB26 and OsMFT1-OsbZIP66 complexes is integral to OsFTIP1-modulated nuclear accumulation of OsMFT1.Our findings also suggest that OsMFT1 might act as a hitherto unknown nucleocytoplasmic trafficking signal that regulates drought tolerance in rice in response to environmental signals.

Pigsties near dwellings as a potential risk factor for the prevalence of Japanese encephalitis virus in adult in Shanxi,China

Background:The increasing trend of adult cases of Japanese encephalitis(JE)in China,particularly in northern China,has become an important public health issue.We conducted an epidemiological investigation in the south of Shanxi Province to examine the relationships between mosquitoes,Japanese encephalitis virus(JEV),and adult JE cases.Methods:Mosquito specimens were collected from the courtyards of farmers’households and pig farms in Shanxi Province.Mosquitoes were pooled,homogenized,and centrifuged.Reverse transcription-polymerase chain reaction(RT-PCR)was used to detect mosquito-borne arbovirus genes in homogenates.Specimens positive for these genes were inoculated into the baby hamster kidney cell line(BHK-21)to isolate virus.Minimum infection rate was calculated and phylogenetic analyses were performed.Results:A total of 7943 mosquitoes belonging to six species in four genera were collected;Culex tritaeniorhynchus accounted for 73.08%(5805/7943),C.pipiens pallens for 24.75%(1966/7943),and the remaining 3%(104/7943)consisted of Anopheles sinensis,Aedes vexans,Ae.dorsalis,and Armigeres subalbatus.Sixteen pools were positive for JEV based on RT-PCR using JEV pre-membrane gene nested primers.Phylogenetic analyses showed that all JEVs belonged to genotype I;two pools were positive using Getah Virus(GETV)gene primers.In addition,one JEV strain(SXYC1523)was isolated from C.pipiens pallens specimens.These results indicate that the minimum infection rate of JEV in mosquito specimens collected from the courtyards of farmers’households with pigsties was 7.39/1000;the rate for pig farms was 2.68/1000;and the rate for farmers’courtyards without pigsties was zero.Conclusions:The high-prevalence regions of adult JE investigated in this study are still the natural epidemic focus of JEV.Having pigsties near dwellings is a potential risk factor contributing to the prevalence of adult JE.To prevent the occurrence of local adult JE cases,a recommendation was raised that,besides continuing to implement the Expanded Program on Immunization for children,the government should urge local farmers to cease raising pigs in their own courtyards to reduce the probability of infection with JEV.

The Medium Energy X-ray telescope (ME) onboard the Insight-HXMT astronomy satellite

The Medium Energy X-ray telescope(ME) is one of the three main telescopes on board the Insight hard X-ray modulation telescope(Insight-HXMT) astronomy satellite. ME contains 1728 pixels of Si-PIN detectors sensitive in 5-30 ke V with a total geometrical area of 952 cm^2. The application specific integrated circuit(ASIC) chip, VA32TA6, is used to achieve low power consumption and low readout noise. The collimators define three kinds of field of views(FOVs) for the telescope, 1°×4°, 4°×4°,and blocked ones. Combination of such FOVs can be used to estimate the in-orbit X-ray and particle background components.The energy resolution of ME is ~3 ke V at 17.8 ke V(FWHM) and the time resolution is 255 μs. In this paper, we introduce the design and performance of ME.

The OsFTIP6-OsHB22-OsMYBR57 module regulates drought response in rice

Plants have evolved a sophisticated set of mechanisms to adapt to drought stress.Transcription factors play crucial roles in plant responses to various environmental stimuli by modulating the expression of numerous stress-responsive genes.However,how the crosstalk between different transcription factor families orchestrates initiation of the key transcriptional network and the role of posttranscriptional modification of transcription factors,especially in cellular localization/trafficking in response to stress in rice,remain still largely unknown.In this study,we isolated an Osmybr57 mutant that displays a drought-sensitive phenotype through a genetic screen for drought stress sensitivity.We found that OsMYBR57,an MYB-related protein,directly regulates the expression of several key drought-related OsbZ/Ps in response to drought treatment.Further studies revealed that OsMYBR57 interacts with a homeodomain transcription factor,OsHB22,which also plays a positive role in drought signaling.We further demonstrate that OsFTIP6 interacts with OsHB22 and promotes the nucleocytoplasmic translocation of OsHB22 into the nucleus,where OsHB22 cooperates with OsMYBR57 to regulate the expression of drought-responsive genes.Our findings have revealed a mechanistic framework underlying the OsFTIP6-0sHB22-0sMYBR57 module-mediated regulation of drought response in rice.The OsFTIP6-mediated OsHB22 nucleocytoplasmic shuttling and OsMYBR57-0sHB22 regulation of OsbZIP transcription ensure precise control of expression of OsLEA3 and Rab21,and thereby regulate the response to water deficiency in rice.

Re-isolation of Wuxiang Virus from Wild Sandflies Collected from Yangquan County, China

We previously isolated a new species of the genus Phlebovirus from wild sandflies collected from Wuxiang County in central China,which named the Wuxiang virus(WUXV).In this study,we re-isolated the WUXV from wild sandflies collected from two villages in Yangquan County,China in 2019.Four virus isolates that caused cytopathic effects in BHK-21 cells were successfully isolated from sandfly specimens collected from chicken pens and sheep pens.Phylogenetic analyses of the L,M and S gene segments of the viruses revealed that the four virus strains represented the previously isolated WUXV.The minimum infection rate(MIR)of the virus isolated from the sheep pen was 3.21,and the MIR of the virus isolated from the chicken pen was 3.45.The positive rates of Wuxiang virus neutralizing antibodies in serum samples of local healthy people and domestic chickens were 8.7%(4/46)and 100%(4/4),respectively,suggesting that Wuxiang virus can infect human and animal.In view of the fact that Wuxiang virus is infectious to humans and animals and has a relatively wide geographical distribution in China,it is of great public health significance to strengthen the investigation and study on the infection status of Wuxiang virus in humans and animals.

The role of histone methylation in the development of digestive cancers:a potential direction for cancer management

Digestive cancers are the leading cause of cancer-related death worldwide and have high risks of morbidity and mortality.Histone methylation,which is mediated mainly by lysine methyltransferases,lysine demethylases,and protein arginine methyltransferases,has emerged as an essential mechanism regulating pathological processes in digestive cancers.Under certain conditions,aberrant expression of these modifiers leads to abnormal histone methylation or demethylation in the corresponding cancer-related genes,which contributes to different processes and phenotypes,such as carcinogenesis,proliferation,metabolic reprogramming,epithelial–mesenchymal transition,invasion,and migration,during digestive cancer development.In this review,we focus on the association between histone methylation regulation and the development of digestive cancers,including gastric cancer,liver cancer,pancreatic cancer,and colorectal cancer,as well as on its clinical application prospects,aiming to provide a new perspective on the management of digestive cancers.

Emergence of Zika Virus in Culex tritaeniorhynchus and Anopheles sinensis Mosquitoes in China

Zika virus(ZIKV)has been isolated from mosquitoes such as Aedes,Mansonia uniformis,and Culex perfuscus;However,the isolation of ZIKV from Anopheles sinensis and Culex tritaeniorhynchus has not yet been reported.In June and July2018,22,985 mosquitoes and 57,500 midges were collected in Jiangxi Province in southeastern China.Among them,six strains of ZIKV were isolated from mosquitoes:four from An.sinensis and two from Cx.tritaeniorhynchus.Molecular genetic analysis showed that the ZIKV isolated from An.sinensis and Cx.tritaeniorhynchus belonged to genotype 2 in the Asian evolutionary branch of ZIKV.In addition,the ZIKV strains isolated from An.sinensis and Cx.tritaeniorhynchus had amino acid substitutions identical to ZIKV strains prevalent in South America since 2015.This study is the first to isolate ZIKV from mosquito specimens collected in the wild of Jiangxi Province,China;This is also the first time that ZIKV has been isolated from An.sinensis and Cx.tritaeniorhynchus.Given that An.sinensis and Cx.tritaeniorhynchus have a very wide geographical distribution in China and even in eastern and southern Asia,the isolation of several strains of ZIKV from these two mosquitoes poses new challenges for the prevention and control of ZIKV infection in the mainland of China and countries and regions with the same distribution of mosquitoes.

Characterization of viromes within mosquito species in China

Mosquitoes are vectors of multiple disease-causing agents that cause worldwide outbreaks of serious infectious diseases in both humans and animals. These arboviral agents include Dengue virus (DENV), Zika virus (ZIKV), chikungunya virus, yellow fever virus, Japanese encephalitis virus (JEV),and Rift Valley fever virus. Thus, mosquitoes are key to the study of viral origin, spread, and the epidemic tendency of these infectious diseases (Hall and Macdonald, 2016).

Integrated analysis of gene expression and methylation profiles of novel pancreatic cancer cell lines with highly metastatic activity

Pancreatic cancer is one of the most lethal human malignancies, partly because of its propensity for metastasis. However, highly metastatic human pancreatic cancer cell lines suitable for studies of metastasis are currently lacking. Here we established two highly metastatic human pancreatic cancer cell lines, MIA PaCa-2 In8 and Panc-1 In8, by Matrigel induction assay. The cell lines were further characterized both in vitro and in vivo. MIA PaCa-2 In8 and Panc-1 In8 cells demonstrated increased migration and invasion compared with their respective parental cells. Following injection into nude mice, MIA PaCa-2 In8 and Panc-1 In8 cells resulted in more pulmonary metastases compared with the parental cells. Furthermore, analyses of m RNA, long non-coding RNA, micro RNA, and methylation profiling revealed that these factors were aberrantly regulated in the highly metastatic cells,indicating that they probably affected metastasis. We thus established and characterized two highly metastatic human pancreatic cell lines that could be used as valuable tools for future investigations into the pathogenesis, metastasis, and potential treatment of human pancreatic cancer.

Energetic particles’fluxes and dose in the Radiation Gene Box measured by space radiation detector onboard SJ-10 satellite

Background To evaluate the hazard of space radiation posing to the tissues,it is important to obtain exact fluxes of different radiation particles.The Radiation Gene Box(RGB)onboard SJ-10 spacecraft was an instrument designed to investigate the effects of space environment on the mESCs and drosophila.To derive the dose received by the tissues inside the RGB,the Space Radiation Detector(SRD)was installed inside it.Purpose The SRD was designed to derive the fluxes of electron,proton,hellion and gamma rays around it.If the type of the particles,the energies,the fluxes and the conversion coefficients are known,the dose received by the tissues could be evaluated.Methods The SRDwas designed as a △E-E solid-state telescope.By measuring the energy deposited in the three subdetectors,the particles’type and their energies could be discriminated.The data of SRDwere divided into 15 bins by the types of particles and their energy ranges.Results The gamma ray flux was higher than any other particle flux inside the RGB,and the electron was the most intense charge particle,while the helium ion was the most harmful radiation to the cells inside the RGB.Conclusion The dose rate inside the Radiation Gene Box was much higher than in the ground,but the integral dose of 12 days inside the RGB was about 2.13 mSv.It seemed unlikely to have obvious biological effects on the tissues of mice and drosophila.

Recovery and Genetic Characterization of a West Nile Virus Isolate from China

West Nile virus(WNV)is an important neurotropic flavivirus that is widely distributed globally.WNV strain XJ11129 was first isolated in Xinjiang,China,and its genetic and biological characteristics remain largely unknown.In this study,phylogenetic and sequence analyses revealed that XJ11129 belongs to lineage 1 a and shares high genetic identity with the highly pathogenic strain NY99.Then,the full-length genomic c DNA of XJ11129 was amplified and assembled using a modified Gibson assembly(GA)method.The virus(named r XJ11129)was successfully rescued in days following this method.Compared with other wild-type WNV isolates,r XJ11129 exhibited virulence indistinguishable from that of the NY99 strain in vivo.In summary,the genomic and virulence phenotypes of r XJ11129 were characterized in vivo and in vitro,and these data will improve the understanding of the spread and pathogenesis of this reemerging virus.