Interaction of L-glutamic acid with human T-lymphocytes

A specific interaction of [3H]Glu with T lymphocytes from the blood of healthy donors (Kd = 0.236 microM) was revealed and described. It was found that unlabeled quisqualate, a structural analogue of L-glutamic acid, and unlabeled dipeptides Ala-Glu, Glu-Ala, and Glu-Glu competitively inhibit the specific binding of [3H]Glu to T lymphocytes (with Ki 0.19, 2.4, 3.4, and 1.2 microM, respectively). Binding experiments with conjugates of labeled and unlabeled glutamic acid with dextran showed that the receptors of [3H]Glu are localized on the outer surface of the plasma membrane of T lymphocytes.     

光纤通信系统在输油管道工程中的设计与应用

靖—惠输油管道工程沿线山峰起伏,沟壑纵横,约有30km的无人区,冬春两季多沙尘暴,故该线路对通信系统的实时性和误码率要求很高。通过对卫星通信和光纤通信的经济技术指标对比,并考虑管道沿线通信发展的趋势,选用了光纤通信方案。文章介绍了靖—惠输油管道工程通信系统设计方案,讨论了该通信系统的经济合理性、先进性与实用性,并介绍了该通信系统投入运行后的技术特点。     

Modelling the costs of non-conventional oil: A case study of Canadian bitumen

High crude oil prices, uncertainties about the consequences of climate change and the eventual decline of conventional oil production raise the issue of alternative fuels, such as non-conventional oil and biofuels. This paper describes a simple probabilistic model of the costs of non-conventional oil, including the role of learning-by-doing in driving down costs. This forward-looking analysis quantifies the effects of both learning and production constraints on the costs of supplying bitumen, which can then be upgraded into synthetic crude oil, a substitute to conventional oil. The results show large uncertainties in the future costs of supplying bitumen from Canadian oil sands deposits, with a 90% confidence interval of $7–12 in 2030, and $6–15 in 2060 (2005 US$). The influence of each parameter on the supply costs is examined, with the minimum supply cost, the learning rate (LR), and the depletion curve exponent having the largest influence. Over time, the influence of the LR on the supply costs decreases, while the influence of the depletion curve exponent increases.     

Amplitude comparator based algorithm for directional comparisonprotection of transmission lines

A high-speed directional comparison relay based on an evaluation of the locally measured deviations of the voltage and the phase-shifted current from their prefault values is described. The operation of the relay depends on the power frequency components of the voltage and phase-shifted current deviation signals. The direction to a fault is determined by an amplitude comparator technique which compares a discriminant value with a positive or negative threshold. Simulation studies on a three-phase power system model show that the direction to a fault is determined within the first few milliseconds following the inception of a fault. Studies over a wide range of faults and source impedance angles show that the proposed amplitude comparator technique performs better than an analogous phase comparator technique     

Laboratory investigation of an amplitude comparator baseddirectional comparison digital protection scheme

A directional comparison digital protection scheme has been implemented with a 16-b single-board computer at each end of a physical model of a transmission line, with communication between the two ends. The protection algorithm makes use of the fundamental frequency components of the deviation signals of the voltage and phase-shifted current. Software routines have been developed for fault monitoring, directional determination, and the trip/block decision. Graphics features incorporated in the software are explained. Tests for various faults conducted on the physical model of a double-circuit transmission line show that the direction to a fault is determined in 3 to 7 ms. The blocking features of the relay are demonstrated     

SENSORY AND INSTRUMENTAL TEXTURE ANALYSIS OF CASSAVA (MANIHOT ESCULENTA, CRANTZ) ROOTS

Two cassava varieties, at three harvesting ages, 6, 12 and 24 months, were analyzed for sensory flavor and texture development. Maximum shear force, Texture Profile Analysis (TPA) and water absorption during cooking were determined at various sampling times. Changes during cooking were described by pseudo‐zero order models for water absorption, flavor and texture development for the fast cooking samples. The 24‐month‐old roots had higher variability and never reached optimum texture or flavor development. Significant pseudo first order models could represent hardness, cohesiveness and chewiness of the TPA, while springiness and adhesiveness varied in a non‐linear fashion. Maximum shear force was 111 N for raw samples and 8.1 N for samples that cooked in less than 25 min. Samples that required longer cook time had on the average a maximum shear force of 19 N.     

CORRELATION AMONG METALLIC IONS,PHENOLIC COMPOUNDS AND ANTIMICROBIAL ACTION IN MEDICINAL PLANTS EXTRACTS

ABSTRACT

The extracts of three different medicinal plants –Calendula officinalis L., Maytenus ilicifolia Martius ex Reissek and Cymbopogon citratus (DC) Stapf – obtained with 70% and 95% v/v ethanol had their antimicrobial activity tested against five pathogenic microorganisms. A quantitative analysis of total phenols, flavonoids and mineral species was performed on the extracts using UV‐vis spectroscopy and atomic absorption spectroscopy. Klebsiella pneumoniae showed the greatest sensibility to the extracts tested. The mineral content of the medicinal herbs varied according to the type of plant (Cu = not detected to 10.90; Zn = 0.85 to 10.04; Na = 24.94 to 153.62; Al = 90.04 to 420.39; Mg = 9.62 to 1,129.15; Ca = 7.15 to 167.27 and K = 913.85 to 9,578.94 µg/g); however, the concentration of heavy elements (Pb, Cd and Cr) was null in the extracts. The concentrations of flavonoids ranged from 13.55 to 41.54 mg/g and 92.35 to 518.28 mg/g for phenolic acids.

PRACTICAL APPLICATIONS

The use of plants with pharmacological activities has increased significantly because of their functional properties in the diet for the promotion of human health and antimicrobial effects. Moreover, medicinal herbs play an important role in public health, especially in developing countries. In Brazil, the use of plant extracts in the treatment of certain diseases is very common. This habit can be explained, at least in part, by the belief that herbs with therapeutic effects do not have toxic effects on the organism. In this paper, ethanolic extracts of three medicinal plants, widely cultivated and used by the population of Brazil and worldwide, had their levels of metals ions and total phenolic compounds determined. Antimicrobial activity of the extracts was evaluated against foodborne pathogens or food spoilage organisms or clinically isolates microorganisms.

     

Coherent网络中的纠错码

网络编码对网络中的传输错误或恶意攻击十分敏感,如果网络拓扑和网络码对于网络的收点和发点都是已知的,这种类型的网络称为Coherent网络。在Coherent网络中,网络汉明重量的概念拉近了网络纠错码和传统纠错码之间的距离,传统纠错码的一些理论和方法有望在将来应用于网络纠错码。类似于传统纠错码,极小距离反映了网络纠错码的纠错能力。利用陪集码理论去描述和研究网络纠错码是一个令人感兴趣的研究方向。