Physiological Mechanism of Exogenous Selenium in Alleviating Mercury Stress on Pakchoi(Brassica campestris L.)

The objective of this study was to explain the physiological mechanisms through which Na_(2)SeO_(3) mitigates the growth and developmental inhibition of pakchoi under HgCl_(2)stress.The results showed that treatment with HgCl_(2)(40 mg L^(−1))led to reduced biomass,dwarfing,root shortening,and root tip necrosis in pakchoi.Compared to control(CK),the activities of superoxide dismutase(SOD)and peroxidase(POD)in Hg treatment increased,and the content of malondialdehyde(MDA)also dramatically increased,which negatively impacted the growth of pakchoi.Low concentrations of Na_(2)SeO_(3)(0.2 mg L^(−1))significantly increased the content of soluble sugars compared with control,while chlorophyll,soluble proteins,free amino acids,and vitamin C had no significant changes.The results of the mixed treatments with HgCl_(2)and Na_(2)SeO_(3) suggested that selenium may be able to reduce the toxicity of mercury in pakchoi.The biomass,plant height,root length,chlorophyll content,soluble protein,other physiological indicators,and proline showed significant increases compared with the HgCl_(2)treatment.Additionally,the MDA content and mercury accumulation in pakchoi decreased.Our results revealed the antagonistic effects of selenium and mercury in pakchoi.Thus,a theoretical basis for studying pakchoi’s mercuryexcreted and selenium-rich cultivation technology was provided.

Study on Optimization of Polymer Enhanced Foam Formulation System

Taking the pilot test area of polymer enhanced foam flooding in Y oilfield as the prototype, a numerical core model was established, and the polymer enhanced foam formulation system was optimized by analyzing the resistance factor and the change rule of oil recovery of different formulation systems. Research shows that the higher the polymer concentration, the greater the resistance factor, and the more obvious the sealing effect formed in the formation. The concentration of surfactant has a greater impact on the resistance factor. With the increase of surfactant concentration, the resistance factor increases significantly, and the plugging effect of foam agent on core is significantly enhanced. With the increase of gas-liquid ratio, the resistance factor first increases and then decreases. When the gas-liquid ratio is 1:1, the resistance is the largest, and the foam agent has the strongest plugging effect on the core. The optimal formula system of polymer enhanced foam flooding in Y oilfield is: polymer concentration is 1200 mg/L, surfactant concentration is 0.25 wt%, gas-liquid ratio is 1:1.

Gelation of Hole Transport Layer to Improve the Stability of Perovskite Solar Cells

To achieve high power conversion efficiency(PCE) and long-term stability of perovskite solar cells(PSCs), a hole transport layer(HTL) with persistently high conductivity, good moisture/oxygen barrier ability, and adequate passivation capability is important. To achieve enough conductivity and effective hole extraction, spiro-OMe TAD, one of the most frequently used HTL in optoelectronic devices, often needs chemical doping with a lithium compound(LiTFSI). However, the lithium salt dopant induces crystallization and has a negative impact on the performance and lifetime of the device due to its hygroscopic nature. Here, we provide an easy method for creating a gel by mixing a natural small molecule additive(thioctic acid, TA) with spiro-OMe TAD. We discover that gelation effectively improves the compactness of resultant HTL and prevents moisture and oxygen infiltration. Moreover, the gelation of HTL improves not only the conductivity of spiro-OMe TAD, but also the operational robustness of the devices in the atmospheric environment. In addition, TA passivates the perovskite defects and facilitates the charge transfer from the perovskite layer to HTL. As a consequence, the optimized PSCs based on the gelated HTL exhibit an improved PCE(22.52%) with excellent device stability.

Improved interfacial adhesion for stable flexible inverted perovskite solar cells

Flexible perovskite solar cells have attracted widespread attention due to their unique advantages in lightweight,high flexibility,and easy deformation,which are suitable for portable electronics.However,the inverted(p-i-n)structured devices suffer from poor stability largely due to the low adhesion at the brittle interface(the hole transport layer/perovskite).Herein,zeolitic imidazolate framework-67(ZIF-67)is applied to inverted structured cells to optimize the interface and prolong the device lifetime.As a result,the flexible devices based on ZIF-67 obtain the champion power conversion efficiency of 20.16%.Over 1000 h under continuous light irradiation,the device retains 96%and 80%of its original efficiency without and with bias,respectively.Notably,devices show mechanical endurance with over 78%efficiency retention after 10,000 cycles of consecutive bending cycles(R=6 mm).The introduction of ZIF-67 suppresses the cracking in device bending,which results in improved environmental stability and bending durability.

Fast-moving target tracking based on mean shift and frame-difference methods

The mean shift tracker has difficulty in tracking fast moving targets and suffers from tracking error accumulation problem. To overcome the limitations of the mean shift method, a new approach is proposed by integrating the mean shift algorithm and frame-difference methods. The rough position of the moving tar- get is first located by the direct frame-difference algorithm and three-frame-difference algorithm for the immobile camera scenes and mobile camera scenes, respectively. Then, the mean shift algorithm is used to achieve precise tracking of the target. Several tracking experiments show that the proposed method can effectively track first moving targets and overcome the tracking error accumulation problem.

Flame-retardant concentrated electrolyte enabling a Li F-rich solid electrolyte interface to improve cycle performance of wide-temperature lithium–sulfur batteries

Lithium–sulfur batteries have been regarded as the most promising high-energy electrochemical energy storage device owing to the high energy density, low cost and environmental friendliness. However, traditional lithium–sulfur batteries using ether-based electrolytes often suffer from severe safety risks(i.e. combustion). Herein, we demonstrated a novel kind of flame-retardant concentrated electrolyte(6.5 M lithium bis(trifluoromethylsulphonyl)imide/fluoroethylene carbonate) for highly-safe and widetemperature lithium–sulfur batteries. It was found that such concentrated electrolyte showed superior flame retardancy, high lithium-ion transference number(0.69) and steady lithium plating/stripping behavior(2.5 m Ah cm^(-2) over 3000 h). Moreover, lithium–sulfur batteries using this flame-retardant concentrated electrolyte delivered outstanding cycle performance in a wide range of temperatures(-10 °C, 25 °C and 90 °C). This superior battery performance is mainly attributed to the LiF-rich solid electrolyte interphase formed on lithium metal anode, which can effectively suppress the continuous growth of lithium dendrites. Above-mentioned fascinating characteristics would endow this flame-retardant concentrated electrolyte a very promising candidate for highly-safe and wide-temperature lithium–sulfur batteries.

Solid-solution partitioning of arsenic(As) in the paddy soil profiles in Chengdu Plain,Southwest China

To predict the long-term behavior of arsenic （As） in soil profiles, the solid-solution partitioning of As was studied in four paddy soil profiles obtained from agricultural areas in Chengdu Plain, Southwest China. Paddy soil profile samples were collected and soil solution samples were extracted. Total As contents in soil solution and soil solid were analyzed, along with the soil solid phase properties. The As in soil solu- tion was significantly higher in the upper layer （0--20 cm） and had a definite tendency to decrease towards 40 cm regardless of the sampling locations. When the concentration of arsenic in soil solution decreased, its content in solid phase increased. Field-based partition coefficient （Kd） for As was determined by calculating the ratio of the amount of As in the soil solid phase to the As concentration in the soil solution. Kj values varied widely in vertical samples and correlated well with soil pH, total organic carbon （TOC） and total As. The results of this study would be useful for evaluating the accumulation trends of hrsenic in soil profiles and in improving the management of the agricultural soils.

Progress in the Study of the Left Atrial Function Index in Cardiovascular Disease:A Literature Review

Some studies have shown that left ventricular structure and function play an important role in the risk stratifi cation and prognosis of cardiovascular disease.The clinical application of left atrial function in cardiovascular disease has gradually attracted attention in the cardiovascular fi eld.There are many traditional methods to evaluate left atrial function.Left atrial function related indexes measured by echocardiography has been identifi ed as a powerful predictor of cardiovascular disease in recent years,but they have some limitations.The left atrial function index has been found to evaluate left atrial function more effectively than traditional parameters.Furthermore,it is a valuable predictor of the risk stratifi cation and prognosis in patients with clinical cardiovascular disease such as heart failure,atrial fi brillation,hypertension,and coronary heart disease.

Morphine pre-exposure facilitates reinstatement but attenuates retention of morphine-induced place preference

BACKGROUND： Drug-associated conditioned stimuli are a key factor to induce morphine relapse. To date, limited evidence is available regarding the impact of drug history on propensity or vulnerability to relapse after long-term abstinence. OBJECTIVE： To determine the effect of morphine pre-exposure on acquisition, maintenance and reinstatement of morphine-induced conditioned place preference （CPP） in rats. DESIGN, TIME AND SETTING： A randomized, controlled, animal experiment was performed at the Laboratory of Behavior Pharmacology, Institute of Psychology, the Chinese Academy of Sciences, from March to September, 2006. MATERIALS： Morphine hydrochloride was purchased from Qinghai Pharmaceutical, China; CPP software was designed and developed by Taiji Software Company, Beijing, China. METHODS： A total of 64 Sprague Dawley rats were randomly assigned to eight groups （n = 8）. Four morphine pretreatment regimens were used （subcutaneous injections, twice daily for 5 consecutive days and a total of 10 times）： （1） ＂intensive＂ （morphine injections with doses escalating from 10 to 60 mg/kg; （2） ＂moderate＂ （one morphine injection at 5 mg/kg dose and one saline injection at 1 mL/kg daily for 5 days）; and （3） ＂single＂ （nine saline injections at 1 mL/kg followed by one morphine injection at 5 mg/kg; （4） control （ten saline injections at 1 mL/kg）. At 5 days after morphine pretreatment, animals were divided into two subgroups that underwent morphine conditioned or saline conditioned training. The test for acquisition of CPP was performed 24 hours after CPP training. The retention of morphine CPP was measured by repeated tests performed weekly for 1 month after the initial test of place preference. After extinction by pairing each chamber with saline, the reinstatement of place preference by low doses of morphine （0.05, 0.15, 0.45 mg/kg） was tested. MAIN OUTCOME MEASURES： Acquisition, maintenance, and recovery response of CPP behavior. RESULTS： The acquisition magnitude of morphine-induced CPP was not affected by prior morphine exposure （F3, 56=0.17, P 〉 0.05）. However, rats treated with moderate or intensive morphine pretreatment showed a less persistent CPP （t = -1.36, P 〉 0.05; t = -1.18, P 〉 0.05）, but their place preference was reinstated by a low dose of morphine priming （t = -2.55, P 〈 0.05; t = -2.54, P 〈 0.05）. The retention and reinstatement of morphine-induced CPP did not differ between rats with single morphine pre-exposure and control rats. CONCLUSION： Morphine pretreatment enhanced reinstatement of morphine-induced CPP but with less persistence. Individuals with heavy drug exposure are more susceptible to drug relapse when re-exposed to addictive drugs.

Investigation of dimensionality in superconducting NbN thin film samples with different thicknesses and NbTiN meander nanowire samples by measuring the upper critical field

We study superconducting properties of NbN thin film samples with different thicknesses and an ultra-thin NbTiN meander nanowire sample.For the ultra-thin samples,we found that the temperature dependence of upper critical field(Hc2)in parallel to surface orientation shows bending curvature close to critical temperature Tc,suggesting a two-dimensional(2D)nature of the samples.The 2D behavior is further supported by the angular dependence measurements of Hc2 for the thinnest samples.The temperature dependence of parallel upper critical field for the thick films could be described by a model based on the anisotropic Ginzburg-Landau theory.Interestingly,the results measured in the field perpendicular to the film surface orientation show a similar bending curvature but in a much narrow temperature region close to Tc for the ultra-thin samples.We suggest that this feature could be due to suppression of pair-breaking caused by local in-homogeneity.We further propose the temperature dependence of perpendicular Hc2 as a measure of uniformity of superconducting ultra-thin films.For the thick samples,we find that Hc2 shows maxima for both parallel and perpendicular orientations.The Hc2 peak for the perpendicular orientation is believed to be due to the columnar structure formed during the growth of the thick films.The presence of columnar structure is confirmed by transmission electron microscopy(TEM).In addition,we have measured the angular dependence of magneto-resistance,and the results are consistent with the Hc2 data.

SAR imaging method for sea scene target based on improved phase retrieval algorithm

Due to the influence of the platform random motion and electromagnetic propagation in turbulent media, the synthetic aperture radar (SAR) high resolution imaging for the sea scenes where there are large amounts of water returns with some target (land) returns is very difficult. To solve this problem, a SAR imaging method based on the improved phase retrieval (PR) algorithm is proposed. First, a filter is added to the conventional PR algorithm which can reduce the influence of water returns on the reconstruction of the targets and improve the reconstruction result of the targets. Then, the corrupted phase of the Fourier transform of the intensity image in the iterative process, which can improve the stability of the iterative algorithm, is used to reduce the recovery errors, and a better recovery performance is achieved. Finally, several experiments are performed to demonstrate the advantages of the proposed method. © 2016 Beijing Institute of Aerospace Information.

Identification and Analysis on True or False Hybrids from Hybridization Populations of Litchi( Litchi chinensis Sonn.) Using EST-SSR Markers

In order to better distinguish true hybrids in litchi crossbreeding,F1generations of two litchi hybridized combinations namely that‘Xuehuaizi’בGuiwei’and‘Xuehuaizi’בJiaohesanyuehong’were used as materials to identify true hybrids,to construct mapping populations and to study the genetic diversities of the two populations with EST-SSR markers.The results showed that F1generations of the two hybrid populations could be identified with an identification rate of100%by the combination of four pair primers,respectively,and the 159 individual plants of the two populations were true hybrids.In addition,variations were exited in leaf morphology of the progenies of the two populations and bands of parents absented were occurred on genotype.The clustering analysis showed that 113 F1plants from the hybridized combination of‘Xuehuaizi’בGuiwei’were clustered into six categories（similarity coefficient was 0.68）,and 63.72%（72 plants）of which clustered into one group with male parent.The genetic distances between 32 plants（28.3%）and their parents were far which indicated that larger variation or recombinant appeared in these plants.Forty six hybrid progenies of the combination of‘Xuehuaizi’בJiaohesanyuehong’were divided into two categories when the similarity coefficient was 0.642 and most individual plants（60.87%）showed closer genetic relationship with female parent and partial maternal genetic tendency.It is concluded that EST-SSR markers are suitable to identify true hybrids of litchi.The construction of the two F1mapping populations has established basis for further genetic linkage mapping,meanwhile,has accumulated materials for cultivar improvement of litchi.

青藏高原牦牛驯化的考古学与遗传学研究进展及展望

家牦牛在史前人类定居青藏高原的过程中起到了巨大作用,但牦牛的驯化过程仍存在诸多未解决的科学问题.本文梳理了牦牛驯化的考古学和遗传学研究进展,展望了开展牦牛驯化与人类定居青藏高原过程研究的未来方向.家牦牛最早的考古学证据来自距今3750年前的青藏高原南部拉萨河谷,但现代遗传学研究显示,牦牛的驯化可追溯至全新世中期,驯化地点最有可能位于西藏东南部的昌都地区,其种群数量增长与人类大规模长年定居青藏高原高海拔地区的历史高度相关,且黄牛的基因渗入对牦牛的驯化过程产生了深刻影响.基于现有研究进展,本文建议:(1)针对青藏高原考古遗址开展系统性的动物考古学研究;(2)应用ZooMS和古DNA技术筛选和鉴定牦牛骨骼遗存,结合古环境DNA进行遗传学研究,追溯牦牛驯化的时间和地点;(3)开展野牦牛与黄牛的杂交驯化模式研究,理解牦牛驯化及其扩散对史前人类在青藏高原生存和发展的促进作用.

The δ^(15)N values of foxtail millet(Setaria italica)and common millet(Panicum miliaceum)are reliable indicators of manuring practices

Millet agriculture,which originated in northern China,alongside rice agriculture,have nurtured the Chinese civilization.Prehistoric manuring practices likely promoted and maintained sustainable millet agricultural production in the loess area of northern China.However,ongoing controversy exists regarding the indicators of prehistoric manuring intensity of foxtail millet(Setaria italica)and common millet(Panicum miliaceum).Here,we present the results of pot and field fertilization experiments on two millet types.Our findings suggest that manuring can significantly increase the δ^(15)N values of foxtail millet,and its δ^(15)N values increase with increasing manuring levels.The δ^(15)N values of foxtail millet leaves are systematically greater than those of grains by approximately 1.6‰.Manuring could have a long-term residual impact on increasing the δ^(15)N values of soil and millet crops.Combined with previous crop fertilization experiment results,we propose that the impact of manuring on the δ^(15)N values of non-nitrogen-fixing crops is roughly consistent.The δ^(15)N value and amount of manure are key factors determining the extent of change in plant δ^(15)N values.The millet grain δ^(15)N values can serve as reliable indicators of manuring practices.Finally,we provide an interpretive framework for assessing the correlation between manuring levels and the δ^(15)N values of archaeological millet remains.The δ^(15)N values of ancient millet grains suggest widespread and intensive manuring practices in prehistoric millet agriculture in northern China,spanning from the early Yangshao period to the Longshan period.

Response to magnesium sulfate and adrenocorticotropic hormone combination therapy for infantile spasms with failed first-line treatments

Importance:Infantile spasm(IS)is a kind of refractory epilepsy.The first-line treatments for IS are adrenocorticotropic hormone(ACTH),oral corticosteroids,and vigabatrin.Objective:This study aimed to evaluate the efficacy of magnesium sulfate and ACTH(MgSO_(4)+ACTH)combination therapy in patients with IS who failed first-line treatments.Methods:In this retrospective study,the clinical data of patients with IS who failed first-line treatments were collected in the Chinese PLA General Hospital.Patients received MgSO_(4)+ACTH combination therapy after first-line treatments failed.The course of treatments was 2 weeks.The therapeutic dose of ACTH and MgSO_(4)was 2.5 U·kg^(-1)·d^(-1)and 0.25 g·kg^(-1)·d^(-1),respectively.Results:A total of 229 patients with IS who failed the first-line treatments were collected.At the end of the MgSO_(4)+ACTH combination treatment,the seizure-free rate was 48.5%(111/229),and the resolution of hypsarrhythmia on electroencephalogram(EEG)was 72.1%(165/229).About 21.4%(49/229)of patients showed side effects,including infectious diseases,hypokalemia,and diarrhea.Interpretation:For patients with IS who failed first-line treatments,in terms of the seizure-free rate and resolution of hypsarrhythmia on EEG,MgSO_(4)+ACTH combination therapy can be considered.

青藏高原发现3000年前的奶制品

奶制品的出现是新石器时代次级产品革命的标志之一,代表着对动物奶、毛、畜力等可以反复利用资源的开发,为早期农业和游牧社会的发展提供了基础.青藏高原人群现代食谱中肉、奶比例相对较高,但缺少史前奶制品利用的直接证据.陶器是新石器时代古人最常用的烹饪和储存工具,检测陶器残留物的脂肪酸组成及碳同位素分布可以指示动物肉类和奶类来源.本文对西藏日喀则南木林县海拔约4000 m的共塘遗址出土陶片进行了脂质残留物分析,结果显示大约3000年前,在雅鲁藏布江中游地区,奶制品消费伴随着当地的牛羊等家养动物同时出现.

Rice use history in Southeast China:Phytolith evidence from the Nanshan site in Fujian Province

The southern spread of rice agriculture is of great academic interest.Although it already has a broad chronological framework,newly introduced rice use and its impact on local subsistence and ecological systems are still unclear.In this study,we explore these issues by analysing phytoliths recovered from continuous sediments of Cave No.4 at the Nanshan site in Fujian Province,together with evidence from surrounding sites.The results show that rice was introduced into southeast China at 7,500 cal.yr BP,but the dominance of the hunting-gathering system was not challenged until later,between 5,000 and 3,500 cal.yr BP,when cultivation of rice,together with foxtail and broomcorn millets,was widely practiced in the region.This suggests that mixed farming in Southeast China,likely originating around the middle Yangtze River,became widespread and gradually systematic during the previous two-millennium adoption.This rice-millet mixed agricultural system changed the former hunting-gathering subsistence system,promoting the agriculturalization process,cultural prosperity and population growth,thus providing a solid basis for rice expansion and cultural migration to Southeast Asia.

Clinical characteristics of hypersensitivity pneumonitis:non-fibrotic and fibrotic subtypes

Background:The presence of fibrosis is a criterion for subtype classification in the newly updated hypersensitivity pneumonitis(HP)guidelines.The present study aimed to summarize differences in clinical characteristics and prognosis of non-fibrotic hypersensitivity pneumonitis(NFHP)and fibrotic hypersensitivity pneumonitis(FHP)and explore factors associated with the presence of fibrosis.Methods:In this prospective cohort study,patients diagnosed with HP through a multidisciplinary discussion were enrolled.Collected data included demographic and clinical characteristics,laboratory findings,and radiologic and histopathological features.Logistic regression analyses were performed to explore factors related to the presence of fibrosis.Results:A total of 202 patients with HP were enrolled,including 87(43.1%)NFHP patients and 115(56.9%)FHP patients.Patients with FHP were older and more frequently presented with dyspnea,crackles,and digital clubbing than patients with NFHP.Serum levels of carcinoembryonic antigen,carbohydrate antigen 125,carbohydrate antigen 153,gastrin-releasing peptide precursor,squamous cell carcinoma antigen,and antigen cytokeratin 21-1,and count of bronchoalveolar lavage(BAL)eosinophils were higher in the FHP group than in the NFHP group.BAL lymphocytosis was present in both groups,but less pronounced in the FHP group.Multivariable regression analyses revealed that older age,<20%of lymphocyte in BAL,and≥1.75%of eosinophil in BAL were risk factors for the development of FHP.Twelve patients developed adverse outcomes,with a median survival time of 12.5 months,all of whom had FHP.Conclusions:Older age,<20%of lymphocyte in BAL,and≥1.75%of eosinophil in BAL were risk factors associated with the development of FHP.Prognosis of patients with NFHP was better than that of patients with FHP.These results may provide insights into the mechanisms of fibrosis in HP.

Using pipette tips to readily generate spheroids comprising single or multiple cell types

Three-dimensional(3D)cell culture methods have been validated that can replicate the tumor environment in vivo to a large extent,providing an effective tool for studying tumors.In this study,we demonstrated the use of standard laboratory pipette tips as micro vessels for generating 3D cell spheroids.No microfabrication or wet-chemistry surface modifications were involved in the procedure.Spheroids consisting of single or multiple cell types were generated within 24 h just by pipetting and incubating a cell suspension in pipette tips.Scanning electron microscope and optical microscope proved that the cells grew together tightly,and suggested that while gravity force might have initiated the sedimentation of cells at the bottom of the tip,the active aggregation of cells to form tight cell-cell interactions drove the formation of spheroids.Using common laboratory micropipettes and pipette tips,the rate of spheroid generation and the generation reproducibility was characterized from five boxes each with 80 tips.The ease of transferring reagents allowed modeling of the growth of microvascular endothelial cells in tumor spheroids.Moreover,the pairing and fusion of tumor spheroids could be manipulated in the pipette tips,suggesting the potential for building and assembling heterogeneous micro-tumor tissues in vitro to mimic solid tumors in vivo.This study demonstrated that spheroids can be readily and cost-effectively generated in standard biological laboratories in a timely manner using pipette tips.

Food resources of the Khog Gzung site on the Tibetan Plateau revealed by sedimentary ancient DNA

Traditional zooarchaeological and archaeobotanical methods based on morphological identification of the excavated faunal and floral remains have been broadly used in reconstructing ancient subsistence economies. However, the accuracy and reliability of these methods rely heavily on the preservation state of the remains. By sequencing the ancient DNA of plants,animals, and microorganisms preserved in sediment, sedimentary ancient DNA(sedaDNA) now offers a novel approach for reconstructing the taxa composition dated back to hundreds of thousands of years. Yet, its application in open-air archaeological sites is rarely reported. In this study, we attempted to apply sedaDNA shotgun metagenomics on the archaeological deposits of the Khog Gzung site(an open-air site dated to 3160–2954 cal yr BP) on the Tibetan Plateau, and then compared the reconstructed taxonomic composition to the unearthed remains. Results showed that most of the crops and domestic animals identified by the two approaches, such as barley(Hordeum vulgare) and sheep(Ovis aries), are in general consistent. Some species, such as foxtail millet(Setaria italica), however, were only detected by sedaDNA. In addition, a variety of microorganisms were also detected by the sedaDNA. The two approaches combined revealed diversified food resources at the Khog Gzung site, which included crops such as millet, barley and wheat, domestic animals such as sheep and cattle, and likely also wild animals from fishing and hunting. Our data proves that sedaDNA has a great potential in reconstructing the faunal and floral compositions from archaeological deposits, therefore laying the foundation for its border applications.