Torsion in Groups of Integral Triangles

Let 0<γ<π be a fixed pythagorean angle. We study the abelian group Hr of primitive integral triangles (a,b,c) for which the angle opposite side c is γ. Addition in Hr is defined by adding the angles β opposite side b and modding out by π-γ. The only Hr for which the structure is known is Hπ/2, which is free abelian. We prove that for generalγ, Hr has an element of order two iff 2(1- cosγ) is a rational square, and it has elements of order three iff the cubic (2cosγ)x3-3x2+1=0 has a rational solution 0<x<1. This shows that the set of values ofγ for which Hr has two-torsion is dense in [0, π], and similarly for three-torsion. We also show that there is at most one copy of either Z2 or Z3 in Hr. Finally, we give some examples of higher order torsion elements in Hr.

Adeno-associated virus mediated endostatin gene therapy in combination with topoisomerase inhibitor effectively controls liver tumor in mouse model

AIM:rAAV mediated endostatin gene therapy has been examined as a new method for treating cancer.However, a sustained and high protein delivery is required to achieve the desired therapeutic effects.We evaluated the impact of topoisomerase inhibitors in rAAV delivered endostatin gene therapy in a liver tumor model. METHODS:rAAV containing endostatin expression cassettes were transduced into hepatoma cell lines.To test whether the topoisomerase inhibitor pretreatment increased the expression of endostatin,Western blotting and ELISA were performed.The biologic activity of endostatin was confirmed by endothelial cell proliferation and tube formation assays. The anti-tumor effects of the rAAV-endostatin vector combined with a topoisomerase inhibitor,etoposide,were evaluated in a mouse liver tumor model. RESULTS:Topoisomerase inhibitors,including camptothecin and etoposide,were found to increase the endostatin exPression level in vitro.The over-expressed endostatin, as a result of pretreatment with a topoisomerase inhibitor, was also biologically active.In animal experiments,the combined therapy of topoisomerase inhibitor,etoposide with the rAAV-endostatin vector had the best tumor- suppressive effect and tumor foci were barely observed in livers of the treated mice.Pretreatment with an etoposide increased the level of endostatin in the liver and serum of rAAV-endostatin treated mice.Finally,the mice treated With rAAV-endostatin in combination with etoposide showed the longest survival among the experimental models. CONCLUSION:rAAV delivered endostatin gene therapy in combination with a topoisomerase inhibitor pretreatment is an effective modality for anticancer gene therapy.

Immunotherapy in pancreatic cancer:Unleash its potential through novel combinations

Pancreatic cancer is the third leading cause of cancer mortality in both men and women in the United States,with poor response to current standard of care,short progression-free and overall survival.Immunotherapies that target cytotoxic T lymphocyte antigen-4,programmed cell death protein-1,and programmed death-ligand 1 checkpoints have shown remarkable activities in several cancers such as melanoma,renal cell carcinoma,and nonsmall cell lung cancer due to high numbers of somatic mutations,combined with cytotoxic T-cell responses.However,single checkpoint blockade was ineffective in pancreatic cancer,highlighting the challenges including the poor antigenicity,a dense desmoplastic stroma,and a largely immunosuppressive microenvironment.In this review,we will summarize available clinical results and ongoing efforts of combining immune checkpoint therapies with other treatment modalities such as chemotherapy,radiotherapy,and targeted therapy.These combination therapies hold promise in unleashing the potential of immunotherapy in pancreatic cancer to achieve better and more durable clinical responses by enhancing cytotoxic T-cell responses.

Quadratic Stabilization of Switched Uncertain Linear Systems: A Convex Combination Approach

We consider quadratic stabilization for a class of switched systems which are composed of a finite set of continuoustime linear subsystems with norm bounded uncertainties. Under the assumption that there is no single quadratically stable subsystem, if a convex combination of subsystems is quadratically stable, then we propose a state-dependent switching law, based on the convex combination of subsystems, such that the entire switched linear system is quadratically stable. When the state information is not available, we extend the discussion to designing an outputdependent switching law by constructing a robust Luenberger observer for each subsystem.

Fault-sand combination modes and hydrocarbon accumulation in Binhai fault nose of Qikou Sag, Bohai Bay Basin, East China

Based on seismic and logging data,taking the downthrow fault nose of Binhai fault in Qikou Sag as the object of study,we analyzed fault characteristics,sand body distribution,fault-sand combinations and hydrocarbon accumulation to reveal the hydrocarbon enrichment law in the fault-rich area of fault depression lake basin.The results show that the Binhai Cenozoic fault nose is characterized by east-west zoning,the main part of the western fault segment is simple in structure,whereas the broom-shaped faults in the eastern segment are complex in structure,including several groups of faults.The difference of fault evolution controls the spatial distribution of sand bodies.The sand bodies are in continuous large pieces in the downthrow fault trough belt along the Gangdong Fault in the middle segment of the fault nose,forming consequent fault-sand combination;whereas the fault activity period of the eastern part of the fault nose was later,and the sand bodies controlled by paleogeomorphology are distributed in multi-phase north-south finger-shaped pattern,forming vertical fault-sand combination pattern matching with the fault.The configuration between faults and sand bodies,and oil sources and caprocks determine the vertical conductivity,plane distribution and vertical distribution of oil and gas.Two oil and gas accumulation modes,i.e.single main fault hydrocarbon supply-fault sand consequent matching-oil accumulation in multi-layers stereoscopically and fault system transportation-fault sand vertical matching-oil accumulation in banded overlapping layers occur in the middle and eastern segments of the fault nose respectively,and they control the difference of oil and gas distribution and enrichment degree in the Binhai fault nose.

Intact soft clay’s critical response to dynamic stress paths on different combinations of principal stress orientation

Comprehensive tests on Hangzhou intact soft clay were performed, which were used to obtain the soils' critical response to undrained dynamic stress paths under different combinations of principal stress orientation. The different combinations included cyclic principal stress rotation (CPSR for short), cyclic shear with abrupt change of principal stress orientation (CAPSO for short) and cyclic shear with fixed principal stress orientation (CFPSO for short). On one side, under all these stress paths, samples have obvious strain inflection points and shear bands, and the excess pore water pressure is far from the level of initial effective confining pressure at failure. Stress paths of major principal stress orientation (α) alternating from negative and positive have quite different influence on soil's properties with those in which α is kept negative or positive. On the other side, due to the soil's strongly initial anisotropy, samples under double-amplitudes CPSR and CAPSO (or single-amplitude CPSR and CFPSO) have similar properties on dynamic shear strength and pore water pressure development tendency when α is kept within ±45°, while have quite different properties when α oversteps ±45°.

水稻强优势恢复系9311粒重的诱变改良

通过EMS诱变恢复系9311种子筛选到了大粒突变体M316。M316整精米的粒长由原来的6.9mm增加到8.0mm,增幅达15.9%,千粒重由原来31g提高到35.6g,增幅达14.8%,但着粒密度明显变稀,由原来的6.77粒/cm减少到5.61粒/cm,减幅达17.1%,因此单株产量比原品种减产8.7%。并通过M2、M3、M4代该性状分离表现,初步推测该突变为隐性突变。有趣的是,该突变体与培矮64s、粤泰A、广占63s分别配制的F1,与原来组合两优培九、粤优938、丰两优1号相比,不仅千粒重有明显增加,穗长和每穗颖花数有不同程度提高,而着粒密度和其它主要性状未发生劣变,因而单株产量有不同程度提高。说明该突变体在粒重增加的同时,配合力得到显著改良。

The Effects of the Longitudinal Axis of Loading upon Bending, Shear and Torsion of a Thin-Walled Cantilever Channel Beam

Three aluminium channel sections of US standard extruded dimension are mounted as cantilevers with x-axis symmetry. The flexural bending and shear that arise with applied axial torsion are each considered theoretically and numerically in terms of two longitudinal axes of loading not coincident with the shear centre. In particular, the warping displacements, stiffness and stress distributions are calculated for torsion applied to longitudinal axes passing through the section’s centroid and its web centre. The stress conversions derived from each action are superimposed to reveal a net sectional stress distribution. Therein, the influence of the axis position upon the net axial and shear stress distributions is established compared to previous results for each beam when loading is referred to a flexural axis through the shear centre. Within the net stress analysis is, it is shown how the constraint to free warping presented by the end fixing modifies the axial stress. The latter can be identified with the action of a ‘bimoment’ upon each thin-walled section.

Torsional Models of Two-ply Yarn

In this paper,the vector equation of a generaliseddoubly wound helix was derived.Treloar’s pliedyarn geometry could be obtained as a special case ofthe generalised doubly wound helix.The shortest fi-bre length around the surface of a helical tube(formed by fibre helices)was determined by apply-ing variational principles.The fibre length as calcu-lated by using Treloar’s geometry was compared in-directly with the shortest possible fibre length at dif-ferent levels of yarn deformation when some of Tre-loar’s rigid geometrical constraints were relaxed.Anew idea based on non-concentric circles was intro-duced to approximate the fibre helix movement in atwo-ply yarn.A torsional model of two-ply yarnwas developed and the theoretical predictions werecompared with some preliminary experimental re-sults.

A New Multi-Method Combination Forecasting Model for ESDD Predicting

Equal Salt Deposit Density (ESDD) is a main factor to classify contamination severity and draw pollution distribution map. The precise ESDD forecasting plays an important role in the safety, economy and reliability of power system. To cope with the problems existing in the ESDD predicting by multivariate linear regression (MLR), back propagation (BP) neural network and least squares support vector machines (LSSVM), a nonlinear combination forecasting model based on wavelet neural network (WNN) for ESDD is proposed. The model is a WNN with three layers, whose input layer has three neurons and output layer has one neuron, namely, regarding the ESDD forecasting results of MLR, BP and LSSVM as the inputs of the model and the observed value as the output. In the interest of better reflection of the influence of each single forecasting model on ESDD and increase of the accuracy of ESDD prediction, Morlet wavelet is used to con-struct WNN, error backpropagation algorithm is adopted to train the network and genetic algorithm is used to determine the initials of the parameters. Simulation results show that the accuracy of the proposed combina-tion ESDD forecasting model is higher than that of any single model and that of traditional linear combina-tion forecasting (LCF) model. The model provides a new feasible way to increase the accuracy of pollution distribution map of power network.

Experimental study on antitumor effect of arsenic trioxide in combination with cisplatin or doxorubicin on hepatocellular carcinoma

INTRODUCTIONThe main component of a traditional Chinese drug 'Pishuang'. arsenic trioxide (As2O3), has obviously selective anti-tumor effect on human hepatocellular carcinoma (HCC)in both in vitro and in vivo studies[1-5]. Due to limited effectiveness when any anti-carcinogen is used alone and obviously increased toxicity when the dose is raised, there is no exception for As2O3. Furthermore, combined chemotherapy contributes to improve therapeutic effectiveness, disperse toxicity and surmount drug-resistance,in which the combination of traditional Chinese and modern medicine has more advantages and characteristics. As a result,we made an experimental study on anti-tumor effect of As2O3in combination with cisplantin (PDD) or doxorubicin (ADM)on HCC. to investigate the possibility of AS2O3 in combination with PDD or ADM and nature of interaction between them,and to provide experimental basis for clinical application.

数学模型在二元复配杀螨剂最优配比筛选中的应用

采用共毒系数法对复配剂的最优配比进行筛选可能会造成真正最优配比的漏筛,且工作量很大,具有局限性。以朱砂叶螨为试虫,分别对甲氰菊酯、阿维菌素、氯氰菊酯、三氯杀螨醇、氧化乐果、甲氰·阿维、氯氰·三杀和氧乐·甲氰进行毒力测定并对复配剂共毒系数Y进行计算。将甲氰菊酯、氯氰菊酯和氧化乐果在各自复配剂有效成分中的质量分数k进行反正弦转换(X=arcsin(k)1/2),通过SPSS软件拟合k反正弦转换值与共毒系数的数学模型。甲氰·阿维、氯氰·三杀和氧乐·甲氰的数学模型为Y1=-30179.08+769.24X1-4.8472X21;Y2=-251.53+32.34X2-0.6858X22;Y3=-7066.96+266.06X3-2.4267X23。对上述的3个方程进行求导可得:Y1′=769.24-9.6944X1;Y2′=32.34-1.3716X2;Y3′=266.06-4.8534X3。令Y′=0,则有X1=79.34;X2=23.58;X3=54.82。将X1、X2和X3值分别代入各自的方程可以求得甲氰·阿维、氯氰·三杀和氧乐·甲氰复配剂的最大共毒系数分别为340.09、129.71和225.65,将X1、X2和X3值代入X=arcsin(K)1/2中可以求得各单剂在复配剂有效成分中的质量分数k值,根据k值可以求得:甲氰菊酯和阿维菌素的最优配比为28∶1;辛硫磷和啶虫脒的最优配比为1∶5.25;三唑磷和杀虫单最优配比为2∶1。

Theory of Flexural Shear, Bending and Torsion for a Thin-Walled Beam of Open Section

Aspects of the general Vlasov theory are examined separately as applied to a thin-walled channel section cantilever beam under free-end end loading. In particular, the flexural bending and shear that arise under transverse shear and axial torsional loading are each considered theoretically. These analyses involve the location of the shear centre at which transverse shear forces when applied do not produce torsion. This centre, when taken to be coincident with the centre of twist implies an equivalent reciprocal behaviour. That is, an axial torsion applied concentric with the shear centre will twist but not bend the beam. The respective bending and shear stress conversions are derived for each action applied to three aluminium alloy extruded channel sections mounted as cantilevers with a horizontal principal axis of symmetry. Bending and shear are considered more generally for other thin-walled sections when the transverse loading axes at the shear centre are not parallel to the section = s centroidal axes of principal second moments of area. The fixing at one end of the cantilever modifies the St Venant free angular twist and the free warping displacement. It is shown from the Wagner-Kappus torsion theory how the end constrained warping generates an axial stress distribution that varies with the length and across the cross-section for an axial torsion applied to the shear centre. It should be mentioned here for wider applications and validation of the Vlasov theory that attendant papers are to consider in detail bending and torsional loadings applied to other axes through each of the centroid and the web centre. Therein, both bending and twisting arise from transverse shear and axial torsion applied to each position being displaced from the shear centre. Here, the influence of the axis position upon the net axial and shear stress distributions is to be established. That is, the net axial stress from axial torsional loading is identified with the sum of axial stress due to bending and axial stress arising from constrained warping displacements at the fixing. The net shear stress distribution overlays the distributions from axial torsion and that from flexural shear under transverse loading. Both arise when transverse forces are displaced from the shear centre.

The Business of Managing Risk and Network Security:An Exploration of Knowledge Transfer Issues within the Context of Data Security and Countermeasure Trade Offs

The contemporary environment within which command,control,communications,computers and intelligence (C4I platforms exist, have a number of characteristics. These characteristics may be most obviously identified as interconnectivity, international networking, speed of data transfer, the compact nature of electronic information and rapidly changing technology. Information security professionals employ a variety of approaches in order to counter risks within this complex and fluid environment. The gamut of potential security activities ranges form access control through a variety of auditing techniques to secure data communications. This field is broad and well documented. Indeed, the discipline of network risk management and data security is both well developed and sophisticated.This paper addresses twin themes:i.The fundamental issue of the method by which specific approaches are employed. This is a precursor to the adoption of an eventual strategy.ii.The crucial issues revolving around the

Advances in extracellular vesicle-based combination therapies for spinal cord injury

Spinal cord injury is a severe insult to the central nervous system that causes persisting neurological deficits.The currently available treatments involve surgical,medical,and rehabilitative strategies.However,none of these techniques can markedly reverse neurological deficits.Recently,extracellular vesicles from various cell sources have been applied to different models of spinal cord injury,thereby generating new cell-free therapies for the treatment of spinal cord injury.However,the use of extracellular vesicles alone is still associated with some notable shortcomings,such as their uncertainty in targeting damaged spinal cord tissues and inability to provide structural support to damaged axons.Therefore,this paper reviews the latest combined strategies for the use of extracellular vesicle-based technology for spinal cord injury,including the combination of extracellular vesicles with nanoparticles,exogenous drugs and/or biological scaffold materials,which facilitate the targeting ability of extracellular vesicles and the combinatorial effects with extracellular vesicles.We also highlight issues relating to the clinical transformation of these extracellular vesicle-based combination strategies for the treatment of spinal cord injury.

海岛型复合纤维与高收缩纤维混纤网络丝的应用

对海岛型复合纤维与高收缩纤维混纺网络丝的应用进行了研究。混纤网络丝经热湿处理,高收缩聚酯长丝产生高收缩而处于芯层,超细纤维分布在表层,从而使网络丝具有优异的蓬松丰满和柔软细腻的特性,并采用缎纹组织结构,设计开发了新型织物。通过对其风格特征和主要性能,如柔软度、悬垂性、透气性、抗皱性及抗静电性等的测试分析,结果表明,所开发的织物具有柔软悬垂、光泽优雅、手感细腻的桃皮绒新风格。

Pore-Throat Combination Types and Gas-Water Relative Permeability Responses of Tight Gas Sandstone Reservoirs in the Zizhou Area of East Ordos Basin, China

With the aim of better understanding the tight gas reservoirs in the Zizhou area of east Ordos Basin,a total of 222 samples were collected from 50 wells for a series of experiments.In this study,three pore-throat combination types in sandstones were revealed and confirmed to play a controlling role in the distribution of throat size and the characteristics of gas-water relative permeability.The type-I sandstones are dominated by intercrystalline micropores connected by cluster throats,of which the distribution curves of throat size are narrow and have a strong single peak(peak ratio>30%).The pores in the type-II sandstones dominantly consist of secondary dissolution pores and intercrystalline micropores,and throats mainly occur as slice-shaped throats along cleavages between rigid grain margins and cluster throats in clay cement.The distribution curves of throat size for the type-II sandstones show a bimodal distribution with a substantial low-value region between the peaks(peak ratio<15%).Primary intergranular pores and secondary intergranular pores are mainly found in type-III samples,which are connected by various throats.The throat size distribution curves of type-III sandstones show a nearly normal distribution with low kurtosis(peak ratio<10%),and the micro-scale throat radii(>0.5μm)constitute a large proportion.From type-I to type-III sandstones,the irreducible water saturation(Swo)decreased;furthermore,the slope of the curves of Krw/Krg in two-phase saturation zone decreased and the two-phase saturation zone increased,indicating that the gas relative flow ability increased.Variations of the permeability exist in sandstones with different porethroat combination types,which indicate the type-III sandstones are better reservoirs,followed by type-II sandstones and type-I sandstones.As an important factor affecting the reservoir quality,the pore-throat combination type in sandstones is the cumulative expression of lithology and diagenetic modifications with strong heterogeneity.

Compensation of stress intensity factors in hollow cylinders containing several cracks under torsion by electro-elastic coating

In this article, a formulation for a hollow cylinder reinforced with an electroelastic layer is investigated. The hollow cylinder and its electro-elastic coating are under the Saint-Venant torsional loading. First, the solution to the problem containing a Volterra-type screw dislocation is obtained by using the Fourier transform. The problem is then reduced to a set of Cauchy singular integral equations by the distributed dislocation method. Finally, several examples are presented to show the effect of the electro-elastic coating on the reduction of the stress intensity factors at the crack tips.

地下聚合交联成胶的耐酸耐高温凝胶堵剂

研制了用于注蒸汽油藏堵水酸化联合作业的两种地下聚合、交联、成胶的凝胶类堵剂。筛选出的最佳配方如下。①丙烯酰胺体系AM 1:5 0%AM+0 035%引发剂PP+0 02%苯酚+1 0%甲醛液+0 05%稳定剂SS;②疏水缔合共聚体系AM 2:AM 1+1 0%AA+0 06%阳离子疏水缔合单体NA。250℃下的成胶时间,AM 1约为12小时,AM 2约为25小时,可通过配方调整在4～38小时范围改变。生成的凝胶按Sydansk提出的目测相对强度等级为J级,即高刚性凝胶,可抗高温,在250℃至少15天内不变化。表面浸泡在土酸液中的凝胶在250℃下可稳定存在9～10天(15%HCl+5%HF)或16～17天(5%HCl+1%HF)。AM 1的耐温耐酸性好于AM 2;AM 2的耐高温性好于AM 1。在人造岩心中AM 2凝胶堵塞物的突破压力为85 3MPa/m。两种堵剂还可用于封堵蒸汽窜流及高温油藏堵水调剖。图1表1参4。

高效稠油破乳剂LS938-2的研制与应用

以由苯酚、多乙烯多胺、甲醛在二甲苯中制备的胺基化酚醛树脂作起始剂制备PO/EO/PO三嵌段聚醚,聚醚与聚甲基三乙氧基硅烷反应制备含硅聚醚,含硅聚醚与SP169(脂肪醇EO/PO双嵌段聚醚)在乙醇中混配,得到水溶性复配破乳剂LS938 2。详述了合成过程。在70℃和80℃下,加药量60～120mg/L,用于含水24%和32%的辽河油田锦州采油厂老站新鲜稠油室内脱水时,LS938 2的效果好于现场使用的AF8464,脱水率平均提高26 9%,脱水速度较快,界面整齐,污水含油较少,色泽较浅。在锦采老站现场对比试验中,加药量90mg/L,脱水温度70℃,使用LS938 2和AF8464时电脱前原油含水分别为4 5%和16 2%,电脱水后分别为0 15%和0 41%。LS938 2是一种高效稠油破乳剂。表2参7。