Synthesis of Carbon dots from Biomass Chenpi for the Detection of Hg^(2+)

Biomass-derived carbon dots(C-dots)are considered a very important carbon material in metal ion detection of their small environmental impact,simple preparation process,and relatively low cost.A green approach for synthesizing biomass-derived C-dots from Chenpi using a hydrothermal method without further processing is proposed in the present study.The as-synthesized C-dots show excellent fluorescence properties,superior resistance to UV irradiation photobleaching,and high photostability in salt-containing solutions.The C-dots were used in the form of label-free fluorescent probes for sensitively detecting Hg^(2+)selectively.The outcome relationship behaved linearly and was established based on a given range between 10–300 nM concentration,with a detection limit of 7.0 nM.This green strategy obtains a high C-dot quantum yield of 10.8%and satisfactory results in detecting Hg^(2+)in actual water samples.

Transcription factor CabHLH035 promotes cold resistance and homeostasis of reactive oxygen species in pepper

Plant basic helix-loop-helix(bHLH)transcription factors(TFs)play central roles in various abiotic stresses.However,its role in plant cold resistance is largely unknown.Previously,we characterised CaNAC035 in pepper,which positively regulates tolerance to cold,salt and drought stresses tolerance.Here,we identified CabHLH035,a CaNAC035-interacting protein in pepper.To explore its functions in cold stress tolerance,we silenced the gene in pepper via virus-induced gene silencing(VIGS)and overexpressed the gene in Arabidopsis.The results showed that CabHLH035 expression was induced by cold treatment,and silencing of CabHLH035 decreased cold stress tolerance.Conversely,overexpression of CabHLH035 in Arabidopsis increased cold stress tolerance.To investigate homologs genes of C-repeat binding factor(CBF)pathway proteins and reactive oxygen species(ROS)marker gene expression blocking by CabHLH035,we performed yeast one-hybrid(Y1H),dual luciferase and electrophoretic mobility shift assay experiments.The results showed that CabHLH035 bound to the region upstream of the CaCBF1A and CaAPX promoters.Additionally,CaCBF1A bound to the CaDHN4 promoter.Taken together,our results showed that CabHLH035 plays a crucial role in cold stress tolerance and its potential as a target for breeding cold-resistant crops.The findings provide a basis for studying the functions and regulatory network of cold stress tolerance in pepper.

微纳米纤维空气净化滤膜的研究进展

微纳米纤维由于比表面积高、长径比高和孔隙率高等优点在制备空气净化滤膜方面极具应用潜力,但始终面临高的过滤效率和低过滤阻力之间的矛盾。文中首先介绍了不同材料制备的微纳米纤维膜的过滤性能,并对不同材料的特性和过滤效果进行了分析;其次总结了典型的微纳米纤维膜结构,包括纤维形貌、纤维膜内结构和层间结构;最后对高效低阻微纳米空气滤膜今后的发展方向进行了展望。

多级结构聚乙烯醇/聚乳酸空气滤膜的制备及过滤性能

构筑多级结构是提升空气滤膜过滤性能的有效方式。以聚乳酸(PLA)和聚乙烯醇(PVA)为原料,结合熔体和弦波微分溶液静电纺丝技术,制备了多级结构PLA/PVA、PVA/PLA/PVA和驻极处理PVA/PLA/PVA空气滤膜,并研究了多级滤膜的形貌、孔隙率、拉伸和过滤性能。研究表明,多级结构的构筑提高了空气滤膜的拉伸性能、孔隙率和过滤效率。流量为32 mL/min时,驻极处理PVA/PLA/PVA滤膜对0.3μm颗粒的过滤效率和品质因子分别为98.3%和4.3×10^(-2)Pa^(-1),高于PLA滤膜(86.3%和3.3×10^(-2)Pa^(-1))、PLA/PVA滤膜(92.5%和3.4×10^(-2)Pa^(-1))和PVA/PLA/PVA滤膜(94.8%和3.6×10^(-2)Pa^(-1))。其研究结果可为绿色、环保空气滤膜的制备和生产提供参考。

Cloning and Bioinformatics Analysis of PsSFBB Gene in Xinjiang Pear

[ Objective] This study aimed to clone the PsSFBB gene from Xinjiang pear for bioinformatics analysis. [ Method ] PsSFBB gene was cloned from an- thers of Qipan pear by using RT-PCR and RACE technologies for bioinformatics analysis. [Result] A SFBBt-α gene with a full-length of 1 231 bp was cloned and named PsSFBB6-α （Genbank accession number： EU909685）. PsSFBBt-ct gene encodes a protein of 378 amino acids, with an F-box motif composed of about 50 amino acids in the N-temfinal. According to the bioinformatics analysis, the molecular formula of PsSFB6-α protein is C2000 H3034 N517 O558S223, with relative molecu- lar mass of 43 987.5 and isoelectric point of 6.02, and the secondary structure is dominated by or-helices ; theoretically, the half life period is 30 h and the instabil- ity parameter is 55.21, so PsSFBB6-α protein is an instable protein ; in addition, it is predicted that PsSFBB6-α protein is a hydrophilic and non-secreted protein with lyases activity and specifically recognized substrates, which was consistent with the function of F-box protein. [ Conclusion] This study laid the foundation for further research on SFBB proteins and the mechanism of self-incompatibility and provided theoretical basis for breeding of self-compatible cultivars of Xinjiang pear and scientific arrangement of pollination trees in production to increase the yield and quality.

Presence of circulating tumor cells is associated with metabolic-related variables in postoperative patients with early-stage breast cancer

Objective：Although circulating tumor cells（CTCs）have been well-established as promising prognostic biomarkers in both early breast cancer and metastatic settings,little is known regarding the prognostic relevance of CTCs in the long-term postoperative monitoring of patients with non-metastatic breast cancer（non-MBC）.In this study,we investigated the associations of CTCs with clinicopathological features and metabolic-related variables,such as obesity and hyperglycemia.Methods：In this retrospective study,we recruited 264 patients with postoperative stage Ⅰ–Ⅲ breast cancer at Guangdong General Hospital from January 2009 to December 2015.The prevalence and number of CTCs were assessed using the Cell Search System at a median time of 19.0 months[interquartile range（IQR）,7.8–33.0]after surgery.The CTC assay results were correlated with the clinicopathological features and metabolic-related variables.A multivariate logistic regression analysis was performed to further determine the independent predictors of CTCs.Results：CTCs were detected in 10.6%of all patients.The positive rate of CTCs in patients with infiltrating ductal carcinoma was lower than that in patients with other pathological types（9.0%vs.28.6%,P=0.020）.More importantly,the presence of CTCs was correlated with blood glucose level（P=0.015）and high-density lipoprotein level（P=0.030）.The multivariate logistic regression analysis showed that the pathological type[odds ratio（OR）：1.757,95%CI：1.021–3.023;P=0.042]and blood glucose level（OR：1.218,95%CI：1.014–1.465;P=0.035）were independent predictors of the presence of CTCs.Conclusions：This study revealed potential associations between CTCs and metabolic-related factors in Chinese patients with non-MBC and supports the hypothesis that metabolic dysfunction in breast cancer patients might influence the biological activity of metastatic breast cancer,leading to a higher prevalence of CTCs.

Zircon U-Pb geochronology,whole-rock geochemical,and Sr-Nd-Pb isotopic constraints on the timing and origin of Permian and Triassic mafic dykes from eastern North China Craton

This work reports an important episode of extensional,mafic magmatism that impacted the North China Craton(NCC)during the Permo-Triassic and influenced the evolution of this Craton.We sampled 30 representative mafic dykes cropping out in eastern NCC,within the Hebei Province,China.New zircon LA-ICP-MS U-Pb ages,geochemical,and Sr-Nd-Pb isotopic data for these mafic dykes identified them as typical dolerites formed between 211.9±1.3 and 263.9±2.6 Ma.The mafic rocks fall into the alkaline and calc-alkaline series.They are enriched in light rare earth elements,some large ion lithophile elements(e.g.,Rb.Ba,and Sr),K,and Pb,and depleted in Nb,Ta,and Ti.The dykes have high initial 87Sr/86Sr ratios(0.7034-0.7178),negative eNd(t)values(—2.2 to—5.9),and relatively constant initial Pb isotopic ratios,that are EMI-like:(206Pb/204Pb)i=16.39-16.74,(207pb/204pb)j=15.22-15.24,and(208Pb/204Pb)i_=36.66-36.86,respectively.Our results indicate that the Hebei Province dolerites were likely derived from magma gen erated through low-medium degree partial melting(3.0-20%)of an EMI-like garnet-lherzolite mantle source.The parental magmas fractionated olivine,clinopyroxene,and Ti-bearing phases with obvious crustal contamination during rapid ascent and dyke emplacement.Since the possible influence of subduction of the Yangtze Plate has been excluded,we propose a model for the origin of the investigated mafic rocks,involving the Pennian collision between the Siberian Block and the NCC.The mafic dykes of eastern NCC within Hebei Province formed during a period of crustal thinning in response to extension after the early Permian collision.

Mantle plume:the dynamic setting of the origin of Early Paleozoic mafic dykes in Ziyang,Shaanxi Province,Southern Qinling Block,China

The mafic dykes(dolerites)during the Early Paleozoic are widely spread in Langao-Ziyang,southern Qiling Block,and the investigation on these dykes are very important.Previous studies have mainly focused on the Silurian mafic dykes;however,research on the Earlier Paleozoic mafic dykes is relatively weak at present.Therefore,the overall understanding of the mantle source and genetic dynamic setting during the Early Paleozoic in this area is lacking.To study the accurate age and origin of the Early Paleozoic mafic dykes in Ziyang,southern Shaanxi Province,the mafic dykes from dabacunand Qinmingzhai were selected and the petrology,zircon U-Pb chronology,geochemistry,and Sr-Nd-Hf isotopes were studied.Analysis indicates that the mafic dykes studied are mainly composed of dolerite,and they are the products of the Early Ordovician(475.8-480.7 Ma).Furthermore,the dolerites belong to alkaline rock series,and they are characterized by enrichment in LREE,Rb,Ba,Sr,Nb,(87Sr/86Sr)i=0.7020-0.7050,εNd(t)=3.0-4.0),εHf(t)=4.5-12.1,176Hf/177Hf=0.282681-0.282844.This suggests that the mafic dyke were derived from the partial melting of a depleted lithospheric mantle,and the genetic process is mainly controlled by the mantle plume based on the discussion of the genetic model.Furthermore,the genetic process experienced the separation and crystallization of olivine and clinopyroxene at the same time,with little crustal contamination.

Zircon U–Pb dating,geochemical,and Sr–Nd–Pb–Hf isotopic constraints on the age and origin of intermediate to felsic igneous rocks at South Altyn,Xinjiang,China

As a part of a giant trending fault system in the Asian continent and one where a strong zone of left strikeslip fault is present,the Altyn Orogenic belt(AOB)has become an important focus for research.Magmatic rocks are widely distributed across the AOB.However,many investigations have focused primarily on Paleozoic igneous rocks;discussion of Mesozoic related igneous activity is often ignored.Here we present the result of studies of representative diorite and granite rocks outcropping in the AOB,within the Xinjiang Uygur Autonomous Region,South Altyn,China.We present new zircon LA-ICP-MS U-Pb age,geochemical,and Sr-Nd-Pb-Hf isotopic data for these sample suites,identifying them as typical igneous rocks formed between 238±1.5 and 238.8±1.1 Ma.The rocks that we studied fall into the alkaline series,also enriched in light rare earth elements(LREE),some large ion lithophile elements(LILE;e.g.,Rb,Ba,Sr,and K),Pb,Th and U,and depleted in heavy rare earth elements(HREE),Nb,Ta,Hf,and Ti.The granite and diorite have high initial 87Sr/86Sr ratios(0.7062-0.7114),negativeεNd(t)values(-8.8 to-11.3),εHf(t)values(-8.7 to-18.7),and relatively constant Pb isotopic ratios((206-Pb/204Pb)i=6.74-17.884,(207Pb/204Pb)i=15.51-15.58,and(208Pb/204Pb)i=35.36-38.04),respectively.This suggests that the magmas parental to these rocks were generated from the partial melting of the ancient crust.The parental magmas to these rocks experienced a degree of fractionation of plagioclase,K-feldspar,and hornblende,possibly during rapid magma ascent.Based on these studies,we propose a reasonable model for the origin of the investigated rocks from the Xinjiang Uygur Autonomous Region of South Altyn,which involves crustal thickening,lithospheric extension,and asthenosphere upwelling,that induced crustal melting.

Photocrosslinkable human amniotic membrane hydrogel for recovery from spinal cord injury

The recovery and reconstruction of central nervous system function after spinal cord injury(SCI)is a worldwide problem.The difficulty lies in the feasibility issue of new axons passing through the injured area and the negative effect of scarring after injury.As a biological material,the human amniotic membrane(HAM)has the advantages of protecting nerve growth,inhibiting scar formation,and promoting neovascularization,but its weak physical properties are difficult to apply in treating SCI.In this study,HAMs were first decellularized and then chemically grafted with methacrylic anhydride.Next,the composite was photocrosslinked with gelatin methacrylate to prepare a cross-network biological complex.The final complexes prepared by appeal were used for in vitro and in vivo studies of SCI in rats,separately.In the in vitro experiment,the composite scaffold inherited abundant biological factors from the amniotic membrane and had the physical properties of a hydrogel,thus providing a favorable environment for the growth and development of neurons and blood vessels.In the in vivo experiment,the composite reduced scarring and promoted the growth of new nerves.Overall,the composite scaffolds can stably simulate the extracellular microenvironment in SCI defects,regulate pathological changes,and promote the generation of new neurons.Therefore,decellularized HAM hydrogels are promising biocomposite materials for central nerve repair after SCI.

Design strategies for two-dimensional material photodetectors to enhance device performance

Two-dimensional(2D)materials are intensively attractive for fabricating high sensitive photodetectors in terms of atomically thin flexible and ultrafast charge transport feature.Due to their atomically thin body,designing high performance detector requires new physical mechanisms and device structures.In this review,we classify design strategies and device structures into four categories depending on their physical mechanisms(photovoltaic effect,photoconductive effect,photothermoelectric effect or photobolometric effect,and surface plasma-wave-assisted effect),and summarize the device performances.Finally,future prospects and development direction for 2D material photodetectors are described.Those design strategies descriptions about photoelectronic detector provide a reference for high responsivity and fast response speed photodetector at broadband sensing in the future.

3D nickel-cobalt diselenide nanonetwork for highly efficient oxygen evolution

Active, stable and low-cost oxygen evolution reaction(OER) catalyst for electrochemical water splitting is key to efficient energy conversion and storage. Here, we report a three-dimensional(3D) nanonetwork as noble-metal-free electrode consisting of nickel cobalt diselenide(NiCoSe_2) nanobrush arrays on Ni foam(NF) through the initial hydrothermal reaction and subsequent thermal selenization process. Introducing ammonium fluoride as surface controller, different NiCoSe_2 hierarchical architecture can be modulated from nanorods, nanobrush to nanosheets. The unique brush-like NiCoSe_2 possesses high surface area for mass transfer, rough surface with rich active sites, 3D nanostructure preventing the accumulation of O2 bubbles. Compared to NiCoSe_2 nanorods/NF, NiCoSe_2 nanosheets/NF and commercial Ru O2,NiCoSe_2 nanobrush/NF exhibits an enhanced OER performance in alkaline media to reach a low overpotential of 274 m V at the current density of 10 m A/cm2, small Tafel slope and a long-term stability. The developed 3D nanonetwork highlights the nanoscale engineering and offers a promising alternative to noble metal catalysts for electrochemical water oxidation.

经直肠双平面高频超声评估MRKH综合征腹膜代阴道成形术后人工阴道的应用价值

目的探讨经直肠双平面高频超声评估MRKH综合征腹膜代阴道成形术后人工阴道的应用价值。方法前瞻性选取2021年1月至2022年3月深圳市罗湖区人民医院的82例MRKH综合征术前患者(术前组)、30例正常生育期女性(正常对照组)和85例MRKH综合征行腹腔镜下腹膜代阴道成形术后复查患者为研究对象,其中69例术后1个月以内复查的患者为术后A组,16例术后1个月以上复查的患者为术后B组。应用双平面高频超声经直肠在矢状切面和横切面观察MRKH综合征患者术前及术后膀胱尿道后壁与直肠前壁之间间隙形态结构的变化,并在尿道内口水平测量此间隙的厚度;在矢状切面和横切面观察正常对照组膀胱尿道后壁与直肠前壁之间女性阴道形态,并在尿道内口水平测量阴道前后壁的总厚度。采用Kruskal-Wallis H检验比较术前组、正常对照组、术后A组和术后B组尿道内口水平膀胱尿道后壁与直肠前壁之间间隙厚度的差异。结果(1)术前组患者在矢状切面及横切面上膀胱尿道后壁与直肠前壁之间仅见低回声结缔组织,此间隙厚度为3.01(2.33,3.52)mm,彩色多普勒血流成像(CDFI)显示:低回声内可见少许血流信号。(2)正常对照组膀胱尿道后壁与直肠前壁之间的正常阴道在矢状切面和横切面上表现为“三线两区”征,阴道的厚度为(10.07±2.93)mm,CDFI:阴道壁内可见较丰富的血流信号。(3)术后A组患者在矢状切面和横切面上膀胱尿道后壁与直肠前壁之间可见人工阴道,表现为“一线两区”征,厚度为(13.25±3.06)mm,CDFI:人工阴道走行区域可见丰富的血流信号。(4)术后B组患者在矢状切面和横切面上膀胱尿道后壁与直肠前壁之间也可见人工阴道,表现为“一线两区”征,厚度为(11.03±3.26)mm,CDFI:人工阴道走行区域可见较丰富的血流信号。(5)Kruskal-Wallis H检验显示,术前组、正常对照组、术后A组及术后B组尿道内口水平膀胱尿道后壁与直肠前壁之间的厚度差异有统计学意义(H=150.301,P<0.001)。结论经直肠双平面高频超声可为MRKH综合征腹膜代阴道成形术术前及术后膀胱尿道后壁与直肠前壁之间形态结构变化的评估提供直接可靠的影像学依据,还可提供术后人工阴道从形成到成熟不同时间段的声像图特征。

Eplerenone inhibits atrial fibrosis in mutant TGF-β1 transgenic mices..

The purpose of the present study was to study the impacts of eplerenone （EPL）, an antagonist of mineralocorticoid receptors （MR）, on atrial fibrosis in a mouse model with selective fibrosis in the atrium, and to explore the possible mechanisms. Using mutant TGF-β1 transgenic （Tx） mice, we first demonstrated that EPL inhibited atrial fibrosis specifically and decreased mac- rophage accumulation in the atria of these mice. Results from immunohistochemistry and western blotting showed that EPL attenuated protein expression of fibrosis-related molecules such as connective tissue growth factor （CTGF） and fibronectin in the atria of Tx mice. In culture, EPL inhibited gene expression of fibrosis-related molecules such as fibronectin, ct-SMA, and CTGF in TGF-β1-stimulated atrial fibroblasts, Finally, using a co-culture system, we showed that TGF-β1 stimulated atrial fi- broblasts induced migration of macrophages and this was blocked by EPL. EPL also blocked TGF-β1 induced gene expression of intedeukin-6 （IL-6） in atrial fibroblasts. Therefore, we conclude that EPL attenuated atrial fibrosis and macrophage infiltra- tion in Tx mice. TGF-I31 and IL-6 were involved in the impacts of EPL on activation of atrial fibroblasts and interactions be- tween fibroblasts and macrophages.

Salvianolic acid B alleviates oxidative stress in non-alcoholic fatty liver disease by mediating the SIRT3/FOXO1 signaling pathway

Salvianolic acid B(Sal B)is a polyphenolic antioxidant that has been shown to have anti-lipid accumulation,anti-inflammatory,and free oxygen radical scavenging activities in various diseases.Here,we aimed to examine whether Sal B could alleviate non-alcoholic fatty liver disease(NAFLD)and explore the possible mechanisms.Signaling pathways involved in oxidative stress,including SIRT3,SOD2,and FOXO1 pathways,were investigated by Western blotting analysis,RT-qPCR,and immunoprecipitation(IP).In the present study,oleic acid(OA)successfully induced lipid and peroxide accumulation,decreased SIRT3 expression,and increased FOXO1 acetylation.However,Sal B significantly reversed these trends.SIRT3 plasmid transfection further reduced the expression of acetylated FOXO1 and considerably enhanced the regulation of SIRT3 and acetylated FOXO1 induced by Sal B.Following SIRT3 siRNA transfection,Sal B-induced down-regulation of acetylated FOXO1 was blocked,suggesting that Sal B-mediated protection occurred through SIRT3-mediated FOXO1 deacetylation.The SIRT3/FOXO1 pathway was a critical therapeutic target for controlling oxidative stress in NAFLD,and Sal B conferred protection against OA-induced hepatic steatosis and oxidative stress through SIRT3-mediated FOXO1 deacetylation.

Antagonism between coral pathogen Vibrio coralliilyticus and other bacteria in the gastric cavity of scleractinian coral Galaxea fascicularis

Scleractinian corals host numerous microbial symbionts with different types of interactions. The gastric cavity of scleractinian coral, as a semiclosed subenvironment with distinct chemical characteristics(e.g., dissolved O2, pH, alkalinity, and nutrients), harbors a distinct microbial community and a diverse array of bacteria that can be pathogenic or beneficial. Galaxea fascicularis is one of the dominant massive scleractinian coral species on inshore fringing reefs in the northern South China Sea.Although the abundance of coral-associated bacteria has been investigated in G. fascicularis, less is known about the microorganisms in the gastric cavity. In this study, we specially isolated cultivable bacterial strains from the gastric cavity of G.fascicularis collected from Hainan Island using a noninvasive sampling approach. Among the 101 representative bacterial strains, one Vibrio coralliilyticus strain, SCSIO 43001, was found to be a temperature-dependent opportunistic pathogen of G.fascicularis. The antagonistic activity between the 100 strains and V. coralliilyticus SCSIO 43001 was tested using a modified Burkholder diffusion assay. Our results showed that V. coralliilyticus SCSIO 43001 inhibits the growth of Erythrobacter flavus and Sphingomonas yabuuchiae. Additionally, we found that three Pseudoalteromonas strains showed moderate to high antibacterial activity against V. coralliilyticus SCSIO 43001 and several other coral-associated Gram-negative bacterial strains.These results suggest that competition between the coral pathogen and other bacteria also occurs in the gastric cavity of coral, and Pseudoalteromonas strains in the gastric cavity of G. fascicularis may provide a protective role in the defense against coinhabiting coral pathogens at elevated temperature.

Comparing salinities of 0, 10 and 20 in biofloc genetically improved farmed tilapia (Oreochromis niloticus) production systems

A 150 days(150-d)experiment was carried out to investigate the production efficiency,inorganic nitrogen syndrome and bacteria community of indoor biofloc technology(BFT)systems used to rear genetically improved farmed tilapia(Oreochromis niloticus)under 0(S-0),10(S-10),and 20 salinities(S20).The start-up period for BFT was 50,60 and 80 d for S-0,S-10 and S-20 groups,respectively.At steady state,the total ammonium nitrogen(NH4þ-N)and nitrite nitrogen(NO2-N)were lower than 3.0 mg/L and 0.34 mg/L,respectively and no nitrate-nitrogen(NO3-N)accumulation was observed.The fish survival rate was above 95%for all the groups.The final fish biomass of the S-10 group(35.83±1.08 kg/m^(3))was not significantly different from the S-0(34.79±1.33 kg/m^(3))group but was significantly higher than S-20(32.6±1.04 kg/m3).The feed conversion ratio for the tilapia in S-20 was 1.46,which was higher than the ratio in S-0(1.40)and S-10(1.39)tilapia.There was no significant difference in the crude protein content of the back muscle from tilapia of the three experimental groups.No significant difference in blood parameters,except for aspartate aminotransferase and alkaline phosphatase was observed between the three groups.Evaluation of microorganisms in the three BFT systems revealed that Proteobacteria,Bacteroidetes,and Fusobacteria were the top three at the phylum level in all groups.However,a significant difference was observed at the genus level in the bacteria of the three BFTs at different salinity(P<0.05).©2017 Published by Elsevier B.V.on behalf of Shanghai Ocean University.This is an open access article。

Chip-integrated van der Waals PN heterojunction photodetector with low dark current and high responsivity

Two-dimensional materials are attractive for constructing high-performance photonic chip-integrated photodetectors because of their remarkable electronic and optical properties and dangling-bond-free surfaces.However,the reported chip-integrated two-dimensional material photodetectors were mainly implemented with the configuration of metalsemiconductor-metal,suffering from high dark currents and low responsivities at high operation speed.Here,we report a van der Waals PN heterojunction photodetector,composed of p-type black phosphorous and n-type molybdenum telluride,integrated on a silicon nitride waveguide.The built-in electric field of the PN heterojunction significantly suppresses the dark current and improves the responsivity.Under a bias of 1 V pointing from n-type molybdenum telluride to p-type black phosphorous,the dark current is lower than 7 nA,which is more than two orders of magnitude lower than those reported in other waveguide-integrated black phosphorus photodetectors.An intrinsic responsivity up to 577 mA W^(−1) is obtained.Remarkably,the van der Waals PN heterojunction is tunable by the electrostatic doping to further engineer its rectification and improve the photodetection,enabling an increased responsivity of 709 mA W^(−1).Besides,the heterojunction photodetector exhibits a response bandwidth of~1.0 GHz and a uniform photodetection over a wide spectral range,as experimentally measured from 1500 to 1630 nm.The demonstrated chip-integrated van der Waals PN heterojunction photodetector with low dark current,high responsivity and fast response has great potentials to develop high-performance on-chip photodetectors for various photonic integrated circuits based on silicon,lithium niobate,polymer,etc.

Structures of the portal vertex reveal essential protein-protein interactions for Herpesvirus assembly and maturation

Dear Editor,Herpesviridae is a large family of double-stranded DNA(dsDNA)viruses that cause a variety of human diseases ranging from cold sores and chicken pox to congenital defects,blindness and cancer(Chayavichitsilp et al.,2009;Wang et al.,2018).In the past 70 years,substantial advances in our knowledge of the molecular biology of herpesviruses have led to insights into disease pathogenesis and management.However,the mechanism for capsid assembly that requires the ordered packing of about 4,000 protein subunits into the hexons,pentons and triplexes remains elusive.It is still a puzzle how initially identical subunits adopt both hexameric and pentameric conformations in the capsid and select the correct locations needed to form closed shells of the proper size.Biochemical and genetic studies have shown that the portal is involved in initiation of capsid assembly(Newcomb et al.,2005)and functions akin to a DNA-sensor coupling genome-packaging achieved by a genome-packaging machinery-“terminase complex”(Chen et al.,2020;Yunxiang Yang,2020)with icosahedral capsid maturation(Lokareddy et al.,2017).Structural investigations of the herpesvirus portal have proven challenging due to the small size of this dodecamer,which accounts for less than 1%of the total mass of the capsid protein layer and the technical difficulties involved in resolving non-icosahedral components of such large icosahedral viruses(diameter is∼1,250Å).Efforts of many investigators over two decades have made to reconstruct the cryo-electron microscopy(cryo-EM)structure of herpesvirus portal vertex and more recently near-atomic structures of two herpesvirus(herpes simplex virus type 1(HSV-1)and Kaposi’s sarcoma-associated herpesvirus(KSHV))portal vertices were reported(McElwee et al.,2018;Gong et al.,2019;Liu et al.,2019).

Diagnostic value of genetic mutation analysis and mutation profiling of cell-free DNA in intraocular fluid for vitreoretinal lymphoma

Dear editor,Vitreoretinal lymphoma(VRL)is a rare intraocular malignant lymphoma affecting the vitreous and/or retina.Pathological diagnosis is challenging.Retinal biopsies have high risks of irreversible visual impairment(even blind-ness),which are not used in clinics for patients with residual visual function.The limited cellular yield from vit-reous biopsies and the cell lysis also contribute to the low detection rates of VRL using cytopathology[1].