IL-4- and IL-5-secreting lymphocyte populations are preferentially stimulated by parasite-derived antigens in human tissue invasive nematode infections

Helminth infections in humans and animals are associated with strong T helper 2 (Th2) responses. To determine whether parasite-derived Ag preferentially expand a Th2-like cell population, a filter immunoplaque assay was used to enumerate the frequencies (F0) of PBMC and CD4(+)-enriched PBMC from individuals with helminth infections secreting selected cytokines in response to parasite-derived (PAg) and nonparasite antigens (NPAg). In 20 individuals with lymphatic filariasis, frequency analysis of PBMC secreting IL-4 and IFN-gamma indicated that the F0 of PAg-specific IL-4-secreting cells (geometric mean F0 (GM): 1/12,100) was 57-fold higher than the corresponding F0 of NPAg-reactive cells (GM: 1/692,000; p < 0.02). In marked contrast, the F0 of IFN-gamma-secreting cells responding to PAg (GM: 1/2,700) did not differ from those of cells specific for NAPg (GM: 1/3,400; p = 0.83). In another group of helminth-infected individuals, the F0 of highly enriched CD4+ cells secreting IL-4 and IL-5 in response to PAg (GMs: 1/2,600 and 1/5,600 CD4+ cells, respectively) were also found to be significantly higher than those specific for NPAg (GMs: 1/291,000 and 1/303,000 CD4+; p < 0.05 and p < 0.01, respectively), whereas the corresponding F0 of IFN-gamma- and granulocyte-macrophage-CSF-secreting cells were equivalent for PAg and NPag. Furthermore, the proportion of PAg-specific IL-4- and IL-5-secreting CD4+ cells relative to all cells secreting the given cytokine were approximately 29-fold higher than the proportion of NPAg-specific cells secreting these cytokines. Again, the corresponding proportions of Ag-specific IFN-gamma-and GM-CSF-secreting CD4+ cells were equivalent for PAg and NPAg. Thus, in this ex vivo system, a circulating population of IL-4- and IL-5-secreting (Th2-like) cells has been shown to exist in humans; PAg appears to expand these cells preferentially.     

A machine learning system for identifying transmembrane domains from amino acid sequences

We present our machine learning system, that uses inductive logic programming techniques to learn how to identify transmembrane domains from amino acid sequences. Our system facilitates the use of operators such as ‘contains’, that act on entire sequences, rather than on individual elements of a sequence. The prediction accuracy of our new system is around 93%, and this compares favourably with earlier results. This work was carried out with the support of a research grant from ISIS, Fujitsu Laboratories.     

电阻-时间线性转换电路

基于电阻的传感器,如应力规和压阻器件,常用于测量多种物理参数.对于使用数字处理器或微控制器进行数据采集和信号处理的设备来说,传感器的响应必须表现为一种适合于转换成数字格式的形式.把这类传感器的电阻变化转换成一个与之成比例的频率或时间间隔是可取的,所以你就能用一个计数器或定时器来方便地得到数字形式的输出信号.图1所示电路把传感器的电阻RS线性地转换成与之成比例的时间间隔.这一电路实际上是一个张驰振荡器,由一个电流源、一个桥式放大器、一个比较器和一个触发器组成.电流IS分成两路,分别通过R1和R2,就如同这两个电阻并联在一起一样.假定运算放大器是理想放大器,则当RX(R4+RS)大于R1R3/R2时,该电路就起一个振荡器的作用.     

High-power 1320-nm wafer-bonded VCSELs with tunnel junctions

A new long-wavelength vertical-cavity surface-emitting laser structure is described that utilizes AlGaAs-GaAs mirrors bonded to AlInGaAs-InP quantum wells with an intracavity buried tunnel junction. This structure offers complete wavelength flexibility in the 1250-1650 nm fiber communication bands and reduces the high free-carrier losses and bonded junction voltage drops in previous devices. The intracavity contacts electrically bypass the bonded junctions to reduce threshold voltage. N-type current spreading layers and undoped AlGaAs mirrors minimize optical losses. This has enabled 134/spl deg/C maximum continuous-wave lasing temperature, 2-mW room-temperature continuous-wave single-mode power, and 1-mW single-mode power at 80/spl deg/C, in various devices in the 1310-1340 nm wavelength range.     

Correction to the Fukuda-Kawata Young's modulus theory and the Fukuda-Chou strength theory for short fibre-reinforced composite materials

The theories for modulus and strength of short fibre-reinforced composite materials are based on the calculation of the force sustained by fibres crossing an arbitrary line perpendicular to the applied load, called the scan line, in a thin, rectangular specimen. The widely referenced Fukuda-Kawata modulus theory and the Fukuda-Chou strength theory are based on an apparently incorrect procedure for the calculation of the force sustained by the fibres crossing the scan line. The error is explained in detail by comparing the Fukuda-Kawata modulus theory and the Cox modulus theory. The magnitude of this error is calculated for specific cases.     

Oxide scale stresses in polycrystalline Ni200

An X-ray diffraction (sin² ψ) method has been successfully used to measure the oxidation stresses at room temperature in annealed and electropolished samples of polycrystalline Ni200 coupons oxidized in the temperature range 760 to 982° C for 4 h. The stresses on the free surface of the oxide (σ ₁₁ andσ ²²) were compressive and the average stress through the thickness normal to the oxide layer was found to be tensile. Surface stresses on the oxides formed at temperatures up to 927° C were found to be isotropic and both surface stresses and the average normal stress increased with increasing temperature of oxidation. At 982° C, the surface stresses were lower and this was attributed to the deformation and fracture of oxide layer resulting in stress relaxation.     

Electrochemical behaviour of Mn3+/Mn2+, Co3+/Co2+ and Ce4+/Ce4+ redox mediators in methanesulfonic acid

The redox behaviour of Mn³⁺/Mn²⁺, Co³⁺/Co²⁺ and Ce⁴⁺/Ce³⁺ mediators commonly used in indirect oxidation of organic compounds were evaluated in methane sulfonic acid on a glassy carbon working electrode employing cyclic voltammetry. Manganic methanesulfonate exhibits higher instability in dilute methanesulfonic acid. The solid MnO₂ formed during disproportionation on the glassy carbon electrode further affects the reproducibility. Cobaltic methanesulfonate formation occurs only at oxygen evolution region rendering the overall oxidation process less efficient. Ceric methane sulfonate formation is highly efficient over a wide acid concentration range. Ceric methanesulfonate can also be employed over a wide temperature range to oxidize different aromatic compounds.     

FA composition and regiospecific analysis of Acer saccharum (sugar maple tree) and Acer saccharinum (silver maple tree) seed oils

GC analysis was performed to determine regiospecific distribution and FA composition in seed oils of the Aceraceae species, Acer saccharum and A. saccharinum. The oil content in the seeds was low at 5.0% in A. saccharum and 5.8% in A. saccharinum, and the main FA were linoleic (30.8 and 29.4%), oleic (21.3 and 27.6%), palmitic (10.1 and 10.5%), and cis-vaccenic (9.4 and 7.9%) acids, respectively. In addition, both oils contained long-chain monoenes of the n−9 and n−7 groups, including 11-eicosenoic, 13-docosenoic, 15-tetracosenoic, 13-eicosenoic, and 15-docosenoic acids, whereas γ-linolenic acid accounted for 0.8% of total FA in A. saccharum, and 0.5% in A. saccharinum. Regiospecific analysis, performed using the methodology of dibutyroyl derivatives of MAG, indicated that linoleic, oleic, and linolenic acids were mainly esterified at the internal position of TAG in both seed oils, whereas long-chain monoenes of the n−7 group were almost exclusively esterified on the external positions.     

VOID FRACTION PROFILES IN PLANE-POISEUILLE FLOW OF VISCOELASTIC FOAMS

This investigation focuses on slow, isothermal, two-phase flow of gas bubble suspensions in Separan solutions, prepared with the help of a sodium borohydride blowing agent at room temperature. The total residence time in these experiments is much smaller than characteristic times for growth or rise of bubbles. The variation of bubble volume fraction across a narrow gap between two planes, is recorded at two locations along the flow direction. This is done with a Cesium gamma-radiation source focused on a region of area.012 cm² in the flow plane, and a Sodium iodide detector across the channel yielding a resolution of.01 over the range of void fractions investigated from.02 to.08. This measurement allows us to identify conditions under which the two-phase flow may be described by a two fluid model with a uniform bubbly core and a bubble free wall layer. With this two phase flow structure, a relative viscosity equation for the suspension is used to compute an apparent viscosity. Such calculations indicate that the observed reduction in apparent viscosity for the two phase flow may be attributed to a bubbly core which is more shear thinning than the medium. The additional shear thinning factor for the suspension is related to the elasticity of the medium.