Cuttings transport: Back reaming analysis based on a coupled layering-sliding mesh method via CFD

Inadequate hole cleaning is one of the main reasons for inefficient operations in extended-reach drilling.The mechanism of cuttings transport under the back reaming operation,which is frequently adopted to remove the cuttings,has been investigated in this study.To this end,a coupled layering-sliding mesh method with the Eulerian-Granular approach has been established innovatively.The dynamic layering method has been employed to simulate the axial motion of the pipe,whereas the sliding mesh method has been used to simulate the pipe rotation.The back reaming operation of a connector-furnished pipe has been simulated,and the sensitive parameter analysis has been conducted.The results thus obtained demonstrate that the increase in the initial bed height,inclination,and the diameter and length of the connector causes a significant increase in the cuttings concentration.In addition,the cuttings concentration is observed to decrease significantly with the pipe rotation speed.Furthermore,two main factors contribute towards the cuttings accumulation around the connector,namely,the difference in the cross-sectional area and the pushing effect of the connector—like a“bulldozer”.The“bulldozer”effect of the connector dominates when the tripping velocity is significant compared to the velocity of the cuttings.Conversely,the effect of the difference in the cross-sectional area becomes the leading factor for cuttings accumulation.The“bulldozer”effect of the connector causes a more severe impact on hole cleaning.In both cases,increasing the tripping velocity only mildly affects the cuttings concentration.It is therefore suggested that the tripping velocity should be slower than that of the sand during the back reaming operation.Furthermore,increased fluid velocity might lead to a higher accumulated cuttings concentration around the connector when the cuttings bed has not entirely passed through the connector.A significant flow rate can be safely applied after the cuttings have passed through the connector furnished with a large diameter,such as the bottom hole assembly.This exploration serves as an essential guide to predicting and controlling tight spots while back reaming.

Carbon-based interface engineering and architecture design for high-performance lithium metal anodes

Metallic lithium(Li)is considered the“Holy Grail”anode material for the nextgeneration of Li batteries with high energy density owing to the extraordinary theoretical specific capacity and the lowest negative electrochemical potential.However,owing to inhomogeneous Li-ion flux,Li anodes undergo uncontrollable Li deposition,leading to limited power output and practical applications.Carbon materials and their composites with controllable structures and properties have received extensive attention to guide the homogeneous growth of Li to achieve high-performance Li anodes.In this review,the correlation between the behavior of Li anode and the properties of carbon materials is proposed.Subsequently,we review emerging strategies for rationally designing high-performance Li anodes with carbon materials,including interface engineering(stabilizing solid electrolyte interphase layer and other functionalized interfacial layer)and architecture design of host carbon(constructing three-dimension structure,preparing hollow structure,introducing lithiophilic sites,optimizing geometric effects,and compositing with Li).Based on the insights,some prospects on critical challenges and possible future research directions in this field are concluded.It is anticipated that further innovative works on the fundamental chemistry and theoretical research of Li anodes are needed.

Genetic Characteristics of 2009 Pandemic H1N1 Influenza A Viruses Isolated from China's Mainland

A total of 100 H1N1 flu real-time-PCR positive throat swabs collected from fever patients in Zhejiang, Hubei and Guangdong between June and November 2009, were provided by local CDC laboratories. After MDCK cell culture, 57 Influenza A Pandemic (H1N1) viruses were isolated and submitted for whole genome sequencing. A total of 39 HA sequences, 52 NA sequences, 36 PB2 sequences, 31 PB1 sequences, 40 PA sequences, 48 NP sequences, 51 MP sequences and 36 NS sequences were obtained, including 20 whole genome sequences. Sequence comparison revealed they shared a high degree of homology (96%～99%) with known epidemic strains (A/California/04/2009(H1N1). Phylogenetic analysis showed that although the sequences were highly conserved, they clustered into a small number of groups with only a few distinct strains. Site analysis revealed three substitutions at loop 220 (221-228) of the HA receptor binding site in the 39 HA sequences: A/Hubei/86/2009 PKVRDQEG→PKVRDQEA, A/Zhejiang/08/2009 PKVRDQEG→PKVRDQER, A/Hubei/75/2009 PKVRDQEG→PKVRDQGG, the A/Hubei/75/2009 was isolated from an acute case, while the other two were from patients with mild symptoms. Other key sites such as 119, 274, 292 and 294 amino acids of NA protein,627 of PB2 protein were conserved. Meanwhile, all the M2 protein sequences possessed the Ser32Asn mutation, suggesting that these viruses were resistant to adamantanes. Comparison of these sequences with other H1N1 viruses collected from the NCBI database provides insight into H1N1 transmission and circulation patterns.

Reversible Al^(3+) storage mechanism in anatase TiO_(2) cathode material for ionic liquid electrolyte-based aluminum-ion batteries

Rechargeable aluminum ion battery(AIB) with high theoretical specific capacity, abundant elements and low cost engages considerable attention as a promising next generation energy storage and conversion system. Nevertheless, to date, one of the major barriers to pursuit better AIB is the limited applicable cathode materials with the ability to store aluminum highly reversibly. Herein, a highly reversible AIB is proposed using mesoporous TiO2 microparticles(M-TiO2) as the cathode material. The improved performance of Ti O2/Al battery is ascribed to the high ionic conductivity and material stability, which is caused by the stable architecture with a mesoporous microstructure and no random aggregation of secondary particles. In addition, we conducted detailed characterization to gain deeper understanding of the Al^(3+) storage mechanism in anatase Ti O2 for AIB. Our findings demonstrate clearly that Al^(3+)can be reversibly stored in anatase TiO2 by intercalation reactions based on ionic liquid electrolyte. Especially, DFT calculations were used to investigate the accurate insertion sites of aluminum ions in M-Ti O2 and the volume changes of M-TiO2 cells during discharging. As for the controversial side reactions in AIBs, in this work, by normalized calculation, we confirm that M-Ti O2 alone participate in the redox reaction. Moreover, cyclic voltammetry(CV) test was performed to investigate the pseudocapacitive behavior.

Preliminary Discussion on Sand Therapy in Mongolian Medicine

Sand therapy of Mongolian medicine is one of traditional Mongolian medical treatments.It conducts heat energy to the human body through natural hot sand applied on the body,achieving the effect of preventing and curing disease.It is an external treatment method,characterized with easy operation,obvious curative effect and small side effects.Referring to the relevant literature of sand therapy in Mongolian medicine and combined with actual situation,the functions and use of sand therapy are summarized in this article,thereby providing theoretical basis and reference for research on sand therapy.

High-Order Finite Difference Method for Helmholtz Equation in Polar Coordinates

We present a fourth-order finite difference scheme for the Helmholtz equation in polar coordinates. We employ the finite difference format in the interior of the region and derive a nine-point fourth-order scheme. Specially, ghost points outside the region are applied to obtain the approximation for the Neumann boundary condition. We obtain the matrix form of the linear system and the sparsity of the coefficient matrix is favorable for the computation of the Helmholtz equation. The feasibility and accuracy of the method are validated by two test examples which have exact solutions.

Amisulpride augmentation therapy improves cognitive performance and psychopathology in clozapine‑resistant treatment‑refractory schizophrenia:a 12‑week randomized,double‑blind,placebo‑controlled trial

Background:Although clozapine is an effective option for treatment-resistant schizophrenia(TRS),there are still 1/3 to 1/2 of TRS patients who do not respond to clozapine.The main purpose of this randomized,double-blind,placebocontrolled trial was to explore the amisulpride augmentation efficacy on the psychopathological symptoms and cognitive function of clozapine-resistant treatment-refractory schizophrenia(CTRS)patients.Methods:A total of 80 patients were recruited and randomly assigned to receive initial clozapine plus amisulpride(amisulpride group)or clozapine plus placebo(placebo group).Positive and Negative Syndrome Scale(PANSS),Scale for the Assessment of Negative Symptoms(SANS),Clinical Global Impression(CGI)scale scores,Repeatable Battery for the Assessment of Neuropsychological Status(RBANS),Treatment Emergent Symptom Scale(TESS),laboratory measurements,and electrocardiograms(ECG)were performed at baseline,week 6,and week 12.Results:Compared with the placebo group,amisulpride group had a lower PANSS total score,positive subscore,and general psychopathology subscore at week 6 and week 12(PBonferroni<0.01).Furthermore,compared with the placebo group,the amisulpride group showed an improved RBANS language score at week 12(PBonferroni<0.001).Amisulpride group had a higher treatment response rate(P=0.04),lower scores of CGI severity and CGI efficacy at week 6 and week 12 than placebo group(PBonferroni<0.05).There were no differences between the groups in body mass index(BMI),corrected QT(QTc)intervals,and laboratory measurements.This study demonstrates that amisulpride augmentation therapy can safely improve the psychiatric symptoms and cognitive performance of CTRS patients.

Short-term night lighting disrupts lipid and glucose metabolism in Zebra Finches:Implication for urban stopover birds

Night lighting has been shown to affect wild animals.To date,the effects of night lighting on the metabolic homeostasis of birds that spend short time in urban environments remain unclear.Using model bird species Zebra Finch(Taeniopygia guttata),we investigated the effects of short-term night lighting on liver transcriptome,blood glucose,triglyceride,and thyroxine(T4 and T3)levels in birds exposed to two different night lighting duration periods(three days and six days).After three days of night lighting exposure,the expression of genes involved in fat synthesis in the liver was upregulated while the expression of genes involved in fatty acid oxidation and triglyceride decomposition was downregulated.There was also a reduction in blood triglyceride,glucose,and T3 concentrations.However,after six days of night lighting,the expression of genes associated with fatty acid decomposition and hyperglycemia in the liver was upregulated,while the expression of genes involved in fat synthesis was downregulated.Simultaneously,blood glucose levels and T3 concentration increased.These findings indicate that short-term exposure to night lighting can disrupt the lipid and glucose metabolism of small passerine birds,and longer stopovers in urban area with intense night lighting may cause birds to consume more lipid energy.

Variaiton in the composition of small molecule compounds in the egg yolks of Asian Short-toed Larks between early and late broods

The egg yolks of birds contain most of the maternally derived materials required for embryo development and are an important factor influencing embryo development and offspring viability.Individual variation in egg-laying date frequently occurs in passerines inhabiting highly seasonal environments.Females laying in early and late stages of the breeding season encounter different environment temperatures and food conditions,which can affect the levels of metabolities in their bodies,thereby altering the transmission of these materials to the eggs.We test a hypothesis that yolk small molecule compounds of Asian Short-toed Lark(Alaudala cheleensis)could vary between early(mid-May)and late(mid-June)broods.Using the UHPLC-MS/MS method,683 compounds belonging to 21 compound groups are detected in the yolks.The contents of 18 compounds are significantly different between early and late broods.Ten differential compounds are significantly higher in the early laid eggs,among whichγ-aminobutyric acid,creatine,prostaglandins,palmitoleic acid,linoleic acid,and trans linoleic acid are related to low environment temperature response.The eggs laid in late stage exhibit significantly higher levels of 5-L-glutamyl-L-alanine andγ-glutamate-leucine,1,3-dimethyluric acid and mannose,which may be attributed to females in the late group consuming more insects.We suggest conducting a comprehensive investigation to reveal the yolk small molecule compounds mediated maternal effects on offspring phenotypes under varying ecological conditions.

Practicability Evaluation and Improvement of Bloodletting Model Mold in Mongolian Medicine Teaching

According to the problems such as low level and depth of experimental teaching research of Mongolian medicine in higher vocational colleges, lack of applicable teaching model mold, lack of students practical operation in time, and single teaching, the development direction and ideas of bloodletting model mold in Mongolian medicine in vocational Mongolian medicine teaching were proposed to provide valuable reference for the experimental teaching reform of traditional therapy of Mongolian medicine and the teaching reform and development ideas of Mongolian medicine and other traditional medicine.

Two Novel Antifungal Saponins from Tibetan Herbal Medicine Clematis tangutica

Antifungal assay-guided isolation of the ethanol extract of the aerial parts of Clematis tangutica yielded two novel triterpene saponins. Their structures were determined to be 3-O-a-L-arabinopyranosyl hederagenin 28-O-a-L-rhamnopyranosyl ester (1) and 3-O-b-D- glucopyranosyl(14)-a-L-arabinopyranosyl hederagenin 28-O-a-L-rhamnopyranosyl ester (2) on the basis of spectral data and chemical reactions.

A Bandwidth-Link Resources Cooperative Allocation Strategy of Data Communication in Intelligent Transportation Systems

The bandwidth resources allocation strategies of the existing Internet of Vehicles(IoV) are mainly base on the communication architecture of the traditional 802.11 x in the wireless local area network(WLAN). The traditional communication architecture of IoV will easily cause significant delay and low Packet Delivery Ratio(PDR) for disseminating critical security beacons under the condition of high-speed movement, distance-varying communication, and mixed traffic. This paper proposes a novel bandwidth-link resources cooperative allocation strategy to achieve better communication performance under the road conditions of intelligent transportation systems(ITS). Firstly, in traffic scenarios, based on the characteristic to predict the relative position of the mobile transceivers, a strategy is developed to cooperate on the mobile cellular network and the Dedicated Short-Range Communications(DSRC). Secondly, by adopting the general network simulator NS3, the dedicated mobile channel models that are suitable for the data interaction of ITS, is applied to confirm the feasibility and reliability of the strategy. Finally, by the simulation, comparison, and analysis of some critical performance parame-ters, we conclude that the novel strategy does not only reduce the system delay but also improve the other communication performance indicators, such as the PDR and communication capacity.

An interface-reconstruction effect for rechargeable aluminum battery in ionic liquid electrolyte to enhance cycling performances

Aluminum(Al) metal has been regarded as a promising anode for rechargeable batteries because of its natural abundance and high theoretical specific capacity. However, rechargeable aluminum batteries(RABs) using A1 metal as anode display poor cycling performances owing to interface problems between anode and electrolyte. The solid-electrolyte interphase(SEI) layer on the anode has been confirmed to be essential for improving cycling performances of rechargeable batteries. Therefore, we immerse the Al metal in ionic liquid electrolyte for some time before it is used as anode to remove the passive film and expose fresh Al to the electrolyte. Then the reactions of exposed Al, acid, oxygen and water in electrolyte are occurred to form an SEI layer in the cycle. Al/electrolyte/V_2 O_5 full batteries with the thin, uniform and stable SEI layer on Al metal anode perform high discharge capacity and coulombic efficiency(CE). This work illustrates that an SEI layer is formed on Al metal anode in the cycle using a simple and effective pretreatment process and results in superior cycling performances for RABs.

内向整流钾通道对少突胶质前体细胞发育的作用

目的研究内向整流钾通道Kir4.1对少突胶质细胞(OL)发育的作用。方法体外原代分离培养少突胶质前体细胞(OPC),利用PCR和Western blot技术检测OPC和成熟OL中Kir4.1和髓鞘相关蛋白MBP的基因和蛋白表达水平。用desipramine(DES)阻断Kir4.1通道后,再检测细胞增殖和分化及MBP的表达情况。结果Kir4.1在OL细胞中表达升高,阻断Kir4.1可以促进OPC增殖,但是抑制OPC向OL细胞分化。结论Kir4.1在OL细胞发育过程中发挥着重要作用。

Mild spring temperature rising affects the anti-oxidation and immune functions of Asian Short-toed Larks

Background:Predicting the possibility of severe effects of global warming on animals is important for understanding the ecological consequences of climate change on ecosystem.Spring is the season during which birds have to physiologically prepare for the subsequent breeding period,and unusual spring temperature rising probably becomes a heat stress to the birds which have adapted to the low spring temperature.Therefore,it is necessary to understand the physiological effect of spring warming on the temperate birds.Methods:Using the activities of blood anti-oxidative enzymes(SOD,CAT,GPx)and the concentrations of serum immunogloblins(IgA,IgY,IgM)as indicators,we compared the anti-oxidative and immune functions of Asian Shorttoed Larks(Calandrella cheleensis)captured between 10 and 15 March,2015 and housed under conditions of 21°C and 16°C.Results:The SOD activities of birds in 21°C group were significantly lower than those in 16°C group on all the treatment days.The CAT activities of the birds in 21°C group were significantly lower than those in 16°C group on the 1 st,5 th,13 th,17 treatment days.The GPx activities of the birds in 21°C group were signifthicantly lower than those in 16°C group on the 1 st,13 th and 17 th,but significantly higher on the 21 st treatment day.The IgA,IgY and IgM concentrations of birds in 21°C group were significantly lower than those in 16°C group on all the treatment days.Conclusions:This study shows that spring temperature rising negatively influences antioxibative and humoral immune functions,which indicates that spring climate warming might reduce the fitness of the temperate passerine birds which have adapted to the low spring temperature.

A Fast Fourth-Order Method for 3D Helmholtz Equation with Neumann Boundary

We present fast fourth-order finite difference scheme for 3D Helmholtz equation with Neumann boundary condition. We employ the discrete Fourier transform operator and divide the problem into some independent subproblems. By means of the Gaussian elimination in the vertical direction, the problem is reduced into a small system on the top layer of the domain. The procedure for solving the numerical solutions is accelerated by the sparsity of Fourier operator under the space complexity of O(M3). Furthermore, the method makes it possible to solve the 3D Helmholtz equation with large grid number. The accuracy and efficiency of the method are validated by two test examples which have exact solutions.

Elderly Fall Detection Based on Improved SSD Algorithm

We propose an improved a single-shot detector(SSD)algorithm to detect falls of the elderly.The VGG16 network part of the SSD network is replaced with the MobilenetV2 network.At the same time,we change the infrastructure of MobilenetV2 network,the three layers that were not down-sampled at the end were removed,which can make the model structure simpler and faster to detect.The complete Intersection-over-Union(CIoU)loss function is introduced to get a good regression of the target borders that have different sizes and different proportions.We use Feature Pyramid Network(FPN)for up-sampling,it can fuse low-level feature maps with high resolution and high-level feature maps with rich semantic information.For sampling results,we use the Secure Shell(SSH)module to extract different receptive fields,which improves the detection accuracy.Our model ensures that the accuracy of the elderly fall detection remains unchanged,but it greatly improves the detection speed that only takes 10 milliseconds to detect a picture.

A Bayesian Stepwise Discriminant Model for Predicting Risk Factors of Preterm Premature Rupture of Membranes： A Case-control Study

Background： Preterm premature rapture of membrane （PPROM） can lead to serious consequences such as intrauterine infection, prolapse of the umbilical cord, and neonatal respiratory distress syndrome. Genital infection is a very important risk which closely related with PPROM. The preliminary study only made qualitative research on genital infection, but there was no deep and clear judgment about the effects of pathogenic bacteria. This study was to analyze the association of in fections with PPROM in pregnant women in Shaanxi, China, and to establish Bayesian stepwise discriminant analysis to predict the incidence of PPROM. Methods： In training group, the 112 pregnant women with PPROM were enrolled in the case subgroup, and 108 normal pregnant women in the control subgroup using an unmatched case-control method. The sociodemographic characteristics of these participants were collected by face-to-face interviews. Vaginal excretions fiom each participant were sampled at 28 36-6 weeks of pregnancy using a sterile swab. DNA corresponding to Chlamrdia trachomalix （CT）, Ureaplasma urealyticwn （UU）, Candida albicans, group B streptococci （GBS）, herpes simplex virus- 1 （HSV-1）, and HSV-2 were detected in each participant by real-time polymerase chain reaction. A model of Bayesian discriminant analysis was established and then verified by a mull）center validation group that included 500 participants in the case subgroup and 5（10 participants in the control subgroup from five different hospitals in the Shaanxi province, respectively. Results： The sociological characteristics were not significantly different between the case and control subgroups in both training and validation groups （all P 〉 0.05）. In training group, the infection rates of UU （11.6% vs. 3.7%）, CT （17.0% vs. 5.6%）, and GBS （22.3% vs. 6.5%） showed statistically different between the case and control subgroups （all P 〈 0.05）, Iog-transfomacd quantification of UU, CE GBS, and HSV-2 showed statistically different between the case and control subgroups （P 〈 0.05）. All etiological agents were introduced into the Bayesian stepwise discriminant model showed that UU, CT, and GBS infections were the main contributors to PPROM, with coe｜＇ficients of 0.441,3.347, and 4.126, respectively. The accuracy rates of the Bayesian stepwise discriminant analysis between the case and control subgroup were 84.1% and 86.8% in the training and validation groups, respectively. Conclusions： This study established a Bayesian stepwise discriminant model to predict the incidence of PPROM. The UU, CT, and GBS infections were discriminant factors for PPROM according to a Bayesian stepwise discriminant analysis. This model could provide a new method for the early predicting of PPROM in pregnant women.

Two-tube multiplex real-time reverse transcription PCR to detect six human coronaviruses

Dear Editor,Coronaviruses are enveloped positive-strand RNA viruses with 27–33 kb genomes.These viruses are classified into four genera,namely Alphacoronavirus,Betacoronavirus,Gammacoronavirus,and

Significant enhancement in water resistance of Pd/Al2O3 catalyst for benzene oxidation by Na addition

A series of Na-doped 1 wt% Pd/Al2O3 catalysts with different Na loadings were prepared by wet impregnation and tested for the catalytic oxidation of benzene. Suitable addition of Na had a remarkable promotion effect on water resistance and enhancement of low temperature activity of Pd/Al2O3 catalysts. The optimal mole ratio between Na and Pd was 1:1. The properties of the prepared catalysts were characterized by X-ray diffraction (XRD), Brunauer Emmett Teller (BET), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), O2-temperature-programmed desorption (O2-TPD), and in situ DRIFTS. Results indicated that the addition of Na not only decreased the content of adsorbed water species but also increased the amount of liable surface oxygen species, which are likely the key factors for the excellent water resistance of the catalyst. Na addition also improved the mobility of the lattice oxygen species, which was favorable for catalytic activity. Moreover, the well-dispersed negatively charged Pd particles and suitable redox properties derived from Na addition also contributed to the improved performance and water resistance of the Na1Pd1/Al2O3 catalyst. In situ DRIFTS results revealed that benzene was oxidized to maleate and acetate species via intermediate o-benzoquinone species, which finally turned into harmless CO2 and H2O.