Investigation on small molecule-aptamer dissociation equilibria based on antisense displacement probe

Food safety is a major issue to public health and have attracted global attention.Fast,sensitive,and reliable detection methods for food hazardous substances is highly desirable.Aptamers which can bind to the target molecules with high affinity and specificity represent an attractive tool for the recognition of food hazardous substances,which play an important role in the development and application of new food safety detection technology.But current assays for characterizing small molecule-aptamer binding are limited by either the mass sensitivity or the size differentiation ability.Herein,we proposed a comprehensive method for assessing the dissociation equilibria of small molecule-aptamer,which is immobilized-free under ambient conditions.The design employs the Le Chatelier’s principle and could be used to effectively measure small molecule-aptamer interactions.ATP binding aptamer and anti-aflatoxin B1 aptamer were used as the model system to determine their affinity,in which their dissociation equilibria measurements are in excellent close to their previous work.Due to the simplicity and sensitivity of this new method,we believe that it could be recommended as an effective tool for characterizing small molecule-aptamer interactions and promote the further application of small molecular aptamer in food safety.

Growth and physiological responses of Agriophyllum squarrosum to sand burial stress

Agriophyllum squarrosum is an annual desert plant widely distributed on mobile and semi-mobile dunes in all the sandy deserts of China. We studied the growth and physiological properties of A. squarrosum seedlings under different sand burial depths in 2010 and 2011 at Horqin Sandy Land, Inner Mongolia to understand the ability and mechanism that A. squarrosum withstands sand burial. The results showed that A. squarrosum had a strong ability to withstand sand burial. Its survival rate, plant height and biomass increased significantly at a burial depth 25% of seedling height and decreased significantly only when the burial depth exceeded the height of the seedlings; some plants still survived even if the burial depth reached 266% of a seedling height. The malondialdehyde （MDA） content and membrane permeability of the plant did not change significantly as long as the burial depth was not greater than the seedling height; lipid peroxidation increased and cell membranes were damaged if the burial depth was increased further. When subjected to sand burial stress, superoxide dismutase （SOD） and peroxidase （POD） activities and free proline content increased in the seedlings, while the catalase （CAT） activity and soluble sugar content decreased. Sand burial did not lead to water stress. Reductions in photosynthetic area and cell membrane damage caused by sand burial may be the major mechanisms increasing mortality and inhibiting growth of the seedling. But the increases in SOD and POD activities and proline content must play a certain role in reducing sand burial damage.

MoP with rich species generated via radio frequency thermal plasma for higher alcohols synthesis from syngas

In this paper, the molybdenum phosphide(MoP) catalysts(TPR-MoP and TPR-MoP-Pla) were prepared by the traditional method and the RF(radio frequency) thermal plasma technique respectively and characterized by x-ray diffraction(XRD), x-ray photoelectron spectroscopy(XPS), transmission electron microscope(TEM), hydrogen temperature-programmed desorption(H_2-TPD) and carbon monoxide temperature-programmed desorption(CO-TPD) measurements,and their catalytic performance for HAS was evaluated. The results showed that the total and C_(2+) alcohols selectivity of the catalyst after plasma treatment(TPR-MoP-Pla) were enhanced.The enhanced catalytic performance could be related to more dislocation defects and the synergistic effect between Mo^(0–2+) and Mo^(4+) valence species in the TPR-MoP-Pla catalyst. In addition, this work suggests that thermal plasma treatment can be used as a new preparation technique for the synthesis of materials with rich species.

基于高维特征因子的券商客户流失预警模型研究

随着证券行业的竞争日趋激烈,如何留住现有客户并预防潜在的客户流失已成为该行业管理者普遍关心的重要问题之一。本文针对证券行业客户流失进行研究。首先,结合证券行业的实际业务背景,探索了证券行业客户流失的定义;其次,提出了基于高维特征因子的独立性筛选方法;最后,基于筛选的因子,分别构建了客户流失预警日模型和周模型。研究结果表明,资产类因子和非资产类因子对预测客户流失具有显著效果,复合因子的预测效果不显著。客户流失预警日模型的外样本AUC值平均可以达到0.95以上,说明模型具有良好的预测精度。客户流失预警周模型的预测效果与日模型基本一致,并且具有计算成本低、预测效率高、模型更加稳定的特点。本文的研究结果可以为企业进行客户挽回提供策略分析,划分客户群体,针对不同流失风险的客户制定不同的挽回策略。另外,本文提出的流失预警模型在企业实际环境测试中也具有良好表现。

Toward sustainable desertification reversion:A case study in Horqin Sandy Land of northern China

Desertification reversion is an interactive process involving climate, land use change, and water processes. In order to reveal the relationship between desertification reversion and these factors, we analyzed historical data on precipitation, air temperature, desertified land changes, underground water tables, and water body changes in Naiman County in the central part of Horqin Sandy Land. Our analysis showed that during 1961-2010 the annual precipitation fluctuated dramatically and has decreased fairly consistently in recent years. The air temperature increased by 0.50-1.25℃, and the minimum temperature increased more obviously. The desertified land area increased from 42,300 km^2 in 1959 to 62,000 km^2 in 1985, and then declined to about 50,000 km^2 in 2010. The underground water tables have been lowered by about 10 m in the past 30 years, and declined more rapidly in recent years. Desertified land is significantly related to the amount of total cropland, and underground water tables are signifcantly correlated with annual precipitation and the amount of irrigated cropland. Therefore, it is necessary to pursue sustainable desertification reversion without compromising the capacity for local development and restoration of degraded land, through application of appropriate management measures for improving water availability in this region.

Effects of sand burial on dune plants: a review

Burial of different growth stages of plants （e.g., adult plants, seedlings and seeds） is frequent in dune ecosystems. The soil micro-environment, which differs from surface conditions, influences the survival and growth of dune plants. To sum up knowledge about the survival mechanisms of plants under sand burial and to promote practical rehabilitation of dune vegetation, we reviewed relevant published literature and concluded that： （1） Focus in recent years has been on impacts of sand burial on seed germination and seedling emergence. Generally, shallow burial increased seed germination and seedling emergence, but deeper burial was negative. Buried at the same depth, large seeds showed higher germination and seedling emergence rates, attributed to larger energy reserves. （2） Survival, growth and reproduction rates of dune plants show plasticity in response to sand burial. Long-term deep burial is fatal because it creates a physical barrier which overcomes the vertical growth of plants, reduces photosynthetic leaf area, and limits oxygen availability to roots. Modest burial, on the other hand, is advantageous for growth and reproduction of many dune plants, due to protection from excessive temperature and drought. （3） There are few reports concerning effects of sand burial on plant physiology, but a limited number of studies indicate that partial burial increases water use efficiency, chlorophyll content, transpiration rate and net photosynthetic rates. The antioxidant protective enzyme system and osmolyte balance were reported to be involved in the mechanisms of dune plant resistance to burial.

Extraordinary tunable dynamic range of electrochemical aptasensor for accurate detection of ochratoxin A in food samples

We report the design of a sensitive,electrochemical aptasensor for detection of ochratoxin A(OTA)with an extraordinary tunable dynamic sensing range.This electrochemical aptasensor is constructed based on the target induced aptamer-folding detection mechanism and the recognition between OTA and its aptamers results in the conformational change of the aptamer probe and thus signal changes for measurement.The dynamic sensing range of the electrochemical aptasensor is successfully tuned by introduction of free assistant aptamer probes in the sensing system.Our electrochemical aptasensor shows an extraordinary dynamic sensing range of 11-order magnitude of OTA concentration from 10^−8 to 10^2 ng/g.Of great significance,the signal response in all OTA concentration ranges is at the same current scale,demonstrating that our sensing protocol in this research could be applied for accurate detections of OTA in a broad range without using any complicated treatment of signal amplification.Finally,OTA spiked red wine and maize samples in different dynamic sensing ranges are determined with the electrochemical aptasensor under optimized sensing conditions.This tuning strategy of dynamic sensing range may offer a promising platform for electrochemical aptasensor optimizations in practical applications.

Spine system changes in soldiers after load carriage training in a plateau environment: A prediction model research

Background: Low back pain is the most common spinal disorder among soldiers, and load carriage training(LCT) is considered the main cause. We aimed to investigate changes in the spine system of soldiers after LCT at high altitudes and the change trend of the lumbar spine and surrounding soft tissues under different load conditions.Methods: Magnetic resonance imaging scans of the lumbar spines of nine soldiers from plateau troops were collected and processed. We used ImageJ and Surgimap software to analyze changes in the lumbar paraspinal muscles, intervertebral discs(IVDs), intervertebral foramina, and curvature. Furthermore, the multiple linear regression equation for spine injury owing to LCT at high altitudes was established as the mathematical prediction model using SPSS Statistics version 23.0 software.Results: In the paraspinal muscles, the cross-sectional area(CSA) increased significantly from(9126.4±691.6) mm~2 to(9862.7±456.4) mm~2, and the functional CSA(FCSA) increased significantly from(8089.6±707.7) mm~2 to(8747.9±426.2) mm~2 after LCT(P<0.05);however, the FCSA/CSA was not significantly different. Regarding IVD, the total lumbar spine showed a decreasing trend after LCT with a significant difference(P<0.05). Regarding the lumbar intervertebral foramen, the percentage of the effective intervertebral foraminal area of L3/4 significantly decreased from 91.6%±2.0% to 88.1%±2.9%(P<0.05). For curvature, the lumbosacral angle after LCT(32.4°±6.8°) was significantly higher(P<0.05) than that before LCT(26.6°±5.3°), while the lumbar lordosis angle increased significantly from(24.0°±7.1°) to(30.6°±7.4°)(P<0.05). The linear regression equation of the change rate, ΔFCSA%=–0.718+23.085×load weight, was successfully established as a prediction model of spinal injury after LCT at high altitudes.Conclusion: The spinal system encountered increased muscle volume, muscle congestion, tissue edema, IVD compression, decreased effective intervertebral foramen area, and increased lumbar curvature after LCT, which revealed important pathophysiological mechanisms of lumbar spinal disorders in soldiers following short-term and high-load weight training. The injury prediction model of the spinal system confirmed that a load weight <60% of soldiers' weight cannot cause acute pathological injury after short-term LCT, providing a reference supporting the formulation of the load weight standard for LCT.

Litter decomposition in fragile ecosystems:A review

As a linkage between plants and soil,litter decomposition and its effect on nutrient recirculation have an important ecolog‐ical significance as they contribute to soil structure improvement and the restoration of degraded ecosystems.Fragile eco‐systems in arid regions(both hot and cold)are depleted in soil organic matter,and as a result of various factors their circu‐lation of material and energy is slower.Here we discuss how litter decomposition is necessary to maintain the stability of fragile ecosystems.We reviewed research on litter decomposition carried out in arid regions.Our objective in this review is to outline how litter decomposition,and the subsequent buildup of organic matter in soil,is a key process determining the stability of fragile ecosystems.Our review shows that existing studies have focused on the influence of single ecologi‐cal factors on litter decomposition and nutrient cycling,and highlights how the exploration of interactions among factors determining litter decomposition is still lacking.This interaction is a key aspect,since in the real world,decomposition and nutrient return to soil of litter products is affected by multiple factors.We propose a network setup on a cross-regional scale using standardized methods(e.g.,the tea bag method)to understand litter decomposition and nutrient return in frag‐ile ecosystems.Such a unique network could contribute to establish predictive models suitable for litter decomposition and nutrient return in these areas,and thus could provide theoretical and practical support for regional ecological protec‐tion and high-quality development.

Effects of sand burial on growth and antioxidant enzyme activities of wheat(Triticum aestivum L.) in northern China

Growth and physiological responses of wheat to sand burial were studied in Horqin Sandy Land, to determine the impact on productivity and survival as well as antioxidant enzymes responses. This study consisted of one control （no sand） and four sand burial treatments： 25%, 50%, 75% and 100% of seedling height, respectively. Minor burial （25%） had no effect on wheat growth and survival; deep burial （100%） was fatal, and the others had an intermediate effect. Thus, the survival limit to sand burial was equal to seedling height. Sand burial mainly decreased shoot biomass and crop yield, but had small effects on belowground biomass. Superoxide dismutase （SOD） activity increased with time after burial in all treatments with surviving plants. Peroxidase （POD） activity increased after six days under burial, and catalase （CAT） activity de- creased after burial, but recovered after 12 days. The concentration of malondialdehyde （MDA）, a marker for oxidative stress, was low on the sixth day, but increased thereafter with burial depth. Thus, sand burial 〉25% should be avoided due to growth rate reduction leading to reduced crop yield, and even 25% burial showed physiological indicators of stress.

Diversity and composition of culturable fungi in Horqin Sandy Land

Soil fungi play a key role in soil functional performance and ecological restoration.To understand the diversity and composition of culturable fungi in soils of Horqin Sandy Land,China,mobile dune,semi-fixed dune,fixed dune and sandy grassland were selected to investigate the soil fungal diversity using a traditional culture-dependent approach.ITS sequencing was applied to identify the fungal strains.The counts of culturable fungi increased significantly from mobile dune to sandy grassland along the gradient of sandy land restoration.The Shannon-Wiener,Simpson and Evenness indices of culturable fungi ranged from 1.26-1.71,0.22-0.37 and 0.83-0.87,respectively.A total of 27 fungal strains were isolated using dilution plate cultural technique.The 27 fungal isolates were clustered into three groups:Ascomycota,Basidiomycota and Mucoromycota at phylum level,indicating that Ascomycota was the dominant fungal phylum(88.9%of the total).The isolated fungi were grouped into 3 phyla,5 classes,6 orders,11 families and 13 genera.The results show that culturable fungi were diverse in sandy land soils and fungal isolates have potential function in lipid turnover,cellulose degradation and ethanol,glucose and fatty acid production.Future studies should be carried out to explore their ecological and biological function for degraded sandy land restoration.

Effects of sand burial on survival and growth of Artemisia halodendron and its physiological response

There is a great deal of literature on the effects of sand burial upon the survival and growth of desert plants, but the physiological adaption mechanisms of desert plants to sand burial have as yet rarely been studied. Artemisia halodendron is widely distributed in the semi-arid deserts of China and is a dominant species in semi-moving dune vegetation. The growth and physiological properties ofA. halodendron seedlings under different sand burial depths were studied in 2010 and 2011 in the Horqin Sand Land, Inner Mongolia, to better understand the ability and physiological mechanism by which desert plants withstand sand burial. The results showed that A. halodendron as a prammophyte species had a stronger ability to withstand sand burial compared to non-prammophytes, with some plants still surviving even if buried to a depth reaching 225% of seedling height. Although seedling growth was inhibited significantly once the depth of sand burial reached 50% of the seedling height, seedling survival did not decrease significantly until the burial depth exceeded 100% of the seedling height. Sand burial did not result in significant water stress or MDA （Malondialdehyde） accumulation in the seedlings, but membrane permeability increased significantly when the burial depth exceeded 100% of the seedling height. After being subjected to sand burial stress, POD （Peroxidase） activity and proline content increased significantly, but SOD （Superoxide Dismutase） and POD activities and soluble sugar content did not. The primary mechanism resulting in in- creased mortality and growth inhibition were that cell membranes were damaged and photosynthetic area decreased when subjected to the severe stress of sand burial, while proline and POD played key roles in osmotic adjustment and protecting cell membranes from damage, respectively.

Screening of cellulose decomposing fungi in sandy dune soil of Horqin Sandy Land

Cellulose decomposing fungi play an important role in litter decomposition and are decisive in nutrient cycling in sandy land ecosystems. Thirty-one strains were isolated to select efficient cellulose decomposers, and four efficient cellulose decomposing fungi （NM3-1, NM3-2, NM3-3, and NM3-4） were screened using a CMC （carboxymethyl cellulose） carbon source in dune soil of Horqin Sandy Land. They were identified as Asperigillus calidoustus, Fusarium oxysporum, Fusarium solani, and Hypocrea lixii by rDNA-ITS molecular biological methods. Cloth decomposition rates were 15.71%, 15.89%, 17.29%, and 17.89% by the four efficient decomposers incubated for 30 days, respectively. Screening of efficient cellulose decomposers can not only increase the dune soil functional microbe bank, but can also accelerate litter decom- position and available nutrient input in the Horqin Sandy Land.

Successful diagnosis and treatment of jejunal diverticular haemorrhage by full-thickness enterotomy: A case report

BACKGROUND Jejunal diverticula are the rarest of all small bowel diverticula and usually have no classic clinical symptoms.Jejunal diverticular haemorrhage(JDH)is a rare complication and can be difficult to identify and manage,hence it always resulting in a diagnostic delay and unsatisfactory clinical outcomes.Although with the advances in endoscopic technology,no consensus have been reached on the diagnosis and management of JDH,the conventional surgical intervention still remains the mainstream for the management of JDH.We report an unique case of a 63-year-old male who presented with massive haemorrhage from jejunal diverticula,which was successfully managed by initial resuscitation and definitive surgery.CASE SUMMARY A 63-year-old male was admitted as an emergency with 6 h history of haematemesis and melena.The haematemesis appeared to be bright red,with volume exceeding 100 mL.The amount of melena was estimated to be 200 mL.Initially,the patient received fluid resuscitation and three unit blood transfusion.Then,in order to localize the bleeding sites,colonoscopy,upper gastrointestinal endoscopy,and mesenteric angiography were utilized but failed to identify the source of haemorrhage.Informed consent form was obtained for further treatment,and he was treated with an exploratory laparotomy and the bleeding site was successfully located during the procedure.He was diagnosed with JDH.The postoperative period was uneventful,and he was discharged on day 18 after surgery.No rebleeding occurred at the 1-year follow-up.CONCLUSION In patients with gastrointestinal bleeding,if various techniques fail to identify the cause of haemorrhage in small bowel and haemodynamic instability is sustained with continuous resuscitation,we recommend surgical intervention should be the ultimate treatment of choice.

FXYD3 enhances IL-17A signaling to promote psoriasis by competitively binding TRAF3 in keratinocytes

Psoriasis is a common chronic inflammatory skin disease characterized by inflammatory cell infiltration and epidermal hyperplasia.However,the regulatory complexity of cytokine and cellular networks still needs to be investigated.Here,we show that the expression of FXYD3,a member of the FXYD domain-containing regulators of Na+/K+ATPases family,is significantly increased in the lesional skin of psoriasis patients and mice with imiquimod(IMQ)-induced psoriasis.IL-17A,a cytokine important for the development of psoriatic lesions,contributes to FXYD3 expression in human primary keratinocytes.FXYD3 deletion in keratinocytes attenuated the psoriasis-like phenotype and inflammation in an IMQ-induced psoriasis model.Importantly,FXYD3 promotes the formation of the IL-17R-ACT1 complex by competing with IL-17R for binding to TRAF3 and then enhances IL-17A signaling in keratinocytes.This promotes the activation of the NF-κB and MAPK signaling pathways and leads to the expression of proinflammatory factors.Our results clarify the mechanism by which FXYD3 serves as a mediator of IL-17A signaling in keratinocytes to form a positive regulatory loop to promote psoriasis exacerbation.Targeting FXYD3 may serve as a potential therapeutic approach in the treatment of psoriasis.

Dynamical analysis of a diffusive malaria model with fixed latent period in the human and vector populations

To investigate the impact of the fixed latent periods in the human and vector populations on the disease transmission in heterogenous environment,we formulate a nonlocal and time-delayed reaction-diffusion(NLTD-RD)system.By appealing to the next generation operator(NGO),we define the basic reproduction number(BRN)Ro,and prove it as a threshold parameter for indicating whether disease persists or not.Specifically,if o<1,the disease-free equilibrium is globally asymptotically stable,while if Ro>1,the disease is shown to be uniformly persistent.In the homogeneous case that all parameters are assumed to be constants,the explicit expression of o is obtained.We further achieved the global attractivity of the constant equilibria by utilizing Lyapunov functionals.Numerical simulations are performed to verify the theoretical results and the effects of the diffusion rate on disease transmission.

Advances in tissue state recognition in spinal surgery:a review

Spinal disease is an important cause of cervical discomfort,low back pain,radiating pain in the limbs,and neurogenic intermittent claudication,and its incidence is increasing annually.From the etiological viewpoint,these symptoms are directly caused by the compression of the spinal cord,nerve roots,and blood vessels and are most effectively treated with surgery.Spinal surgeries are primarily performed using two different techniques:spinal canal decompression and internal fixation.In the past,tactile sensation was the primary method used by surgeons to understand the state of the tissue within the operating area.However,this method has several disadvantages because of its subjectivity.Therefore,it has become the focus of spinal surgery research so as to strengthen the objectivity of tissue state recognition,improve the accuracy of safe area location,and avoid surgical injury to tissues.Aside from traditional imaging methods,surgical sensing techniques based on force,bioelectrical impedance,and other methods have been gradually developed and tested in the clinical setting.This article reviews the progress of different tissue state recognition methods in spinal surgery and summarizes their advantages and disadvantages.

上消化道早癌筛查的研究进展

上消化道癌是一种严重危害人类健康的疾病,现已成为世界性的公共卫生问题。当前的上消化道癌患者中,有很多人已经到了晚期,他们的生存概率很低,如果能及早发现,就可以大大地提高患者的生存率,减轻患者痛苦。上消化道癌的早期诊断和早期治疗是提高患者生存质量的重要手段。本文就上消化道早癌筛查的必要性、筛查方法、现状以及前景作了简要的论述,阐述了开展上消化道早期癌症筛查和研究对减少患者死亡率具有的重要意义,提出了应进一步扩大筛查规模,为进一步推广上消化道癌筛查奠定基础,希望能为临床合理筛选和推广筛选技术提供参考。

Real-time detection of Cu(Ⅱ)with PEDOT:PSS based organic electrochemical transistors

Copper is an essential element in the environment and the human body,but at the same time,exposure to high concentrations of Cu^(2+) ions will potentially lead to acute toxicity and various neurodegenerative diseases.Thus,it is of great significance for the development of highly sensitive and selective strategies for the detection of Cu^(2+) ions.Here,we report a highly efficient poly(3,4-ethylenedioxythiophene):poly(styrene sulfonic acid)(PEDOT:PSS) based organic electrochemical transistor(OECT)sensor,for real-time Cu^(2+) ions detection.The detection limit of the OECT device is as low as 100 nM,far beyond the sensitivity required for practical uses.The detection mechanism may base on the chemical reactivity of Cu^(2+) ions oxiding the PEDOT:PSS in solution both in absence and presence of the base potential.The OECT devices also exhibit excellent selective response to Cu^(2+)ions rather than other metal ions.Finally,we also demonstrate the determination of Cu^(2+) ions in tap water with the OECT Cu^(2+)sensor.Considering the high sensitivity and selectivity,as well as the real-time and low cost features of our Cu^(2+) OECT sensor,it is ideal for portable and disposable applications for environment monitoring and public health.