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11.
This study assessed the level of vaccine-induced hepatitis B surface antibody that is protective against hepatitis B infection and carriage in The Gambia. Sera from 700 of a cohort of 1041 children vaccinated against hepatitis B in infancy were serially tested for markers of hepatitis B until age 7 years. No absolute level of protection against infection was found, but all children who attained a peak antibody response to vaccination of >=10 IU/L were protected against carriage of hepatitis B surface antigen. Two-thirds of 45 infected children experienced brief infection (determined by loss of core antibody). This transient infection was likely related to surface antibody level. The data support the use of the peak antibody response as the best indicator of protection against carriage and suggest that most infections after vaccination are short-lived.  相似文献   
12.
This part, PART IIB [2], of the document HIGH-SPEED TOOLS FOR GLOBAL INFORMATION MANAGEMENT. II. Specifications and Uses of the Transparent Query Language (TQL) [1–6] contains the specifications for the operations that provide the arithmetic capabilities for Transparent Query Language. PART IIB references PART IIA [1] and PART IIC [3]. Concise definitions of Transparent Query Language terms, Conclusions and Acknowledgments are given in PART IIF [6].  相似文献   
13.
The Guposhan-Huashan batholith was emplaced during transition from Tethysian tectonic regime to Pacific tectonic regime in the Middle-Late Jurassic. The regional EW-striking Yishan-Quannan basement deep fault zone, associated with the Tethysian regime, is thought likely to control the formation of the batholith. The development of the batholith was, however, achieved when the Pacific tectonic extensional regime dominated. The batholith consists of seven individual intrusive units that were emplaced subseque...  相似文献   
14.
Of critical importance is the design of the man-machine interfaces for general rule based systems. They must serve (i) as user-friendly interfaces for different classes of users for different applications and (ii) to invoke service components in integrated packages without interrogating users. These objectives are achieved with a multitier interface design whose two parts, the Interactive User-Friendly Interface (IUFI) and the System Interface (SI), communicate with each other via commonly used notational systems and can be invoked independently of each other. The user-friendly interface, which is uniquely designed for each user discipline, passes information to the SI. The SI does not change for new IUFI designs and it can be invoked by other rule based systems without interrogating users.Here the requirements for the IUFI and SI parts are identified, four different designs of multi-tier interfaces are given and two applications are described. Also included are guidelines for designing user friendly interfaces.  相似文献   
15.
In this part, PART IIE [5], of the document HIGH-SPEED TOOLS FOR GLOBAL INFORMATION MANAGEMENT. II. Specifications and Uses of the Transparent Query Language (TQL) [1–6] the conversion of queries coded in SQL, Relational Algebra, QUEL and Query-By-Examples (QBE) to TQL are demonstrated. PART IIE references PART IIA [1], PART IIB [2], PART IID [3] and PART IIF [6]. Concise definitions of Transparent Query Language terms, Conclusions and Acknowledgments are given in PART IIF [6].  相似文献   
16.
The rapid reactions of nitrosoarenes with cellular SH groups have proved to be main metabolic conversions during detoxication. Interactions of the phenacetin metabolite 4-nitrosophenetole with glutathione have been investigated in detail during the last years, revealing a complex pattern of products depending on the stoichiometry of the reactants and reaction conditions. Eight metabolites have been identified hitherto, and the present work extends this medley by six additional products. Three metastable sulfenamides, 4-ethoxy-2,N-bis(glutathion-S-yl)-aniline, N4-(glutathion-S-yl)-4-amino-4'-ethoxydiphenylamine, and N-(glutathion-S-yl)-4-aminophenol, as well as the N-sulfenylquinonimine N-(glutathion-S-yl)-1,4-benzoquinonimine were characterized by chemical reactivity, chromatographic behavior, UV/vis absorption, 1H NMR, and FAB-MS data. The structure of the sulfenamide 2,N4-bis(glutathion-S-yl)-4-amino-4'-ethoxydiphenylamine could not be proved unequivocally, but is strongly suggested due to the chemical reactivity, chromatographic behavior, and UV/vis absorption of the compound. Finally, traces of 4-aminophenol were detected. A reaction scheme is presented explaining the formation of all identified metabolites via a central sulfenamide cation. Molecular orbital calculations for this sulfenamide cation have been performed, corroborating the proposed reaction mechanisms on the basis of Klopman's generalized perturbation theory.  相似文献   
17.
Maine MA  Suñé NL  Lagger SC 《Water research》2004,38(6):1494-1501
The capacity of Salvinia herzogii and Pistia stratiotes to remove Cr (III) from water and their behaviour at different Cr (III) concentrations were studied in outdoor experiments. Cr distribution in aerial parts and roots with time and the possible mechanisms of Cr uptake were analyzed. Both macrophytes efficiently removed Cr from water at concentrations of 1, 2, 4 and 6 mgCrL(-1). S. herzogii was the best adapted species. At a greater initial concentration, greater bioaccumulation rates were observed. Root Cr uptake was a rapid process that was completed within the first 24h. Cr uptake through direct contact between the leaves and the solution is the main cause of the increase of Cr in the aerial parts, Cr being poorly translocated from the roots to the aerial parts. Both mechanisms were fast processes. The Cr uptake mechanism involves two components: a fast component and a slow one. The former occurs mainly due to the roots and leaves adsorption and is similar for both species. The slow component is different for each species probably because in P. stratiotes a Cr precipitation occurs induced by the roots.  相似文献   
18.
At present all metal foams are produced in small quantities using time and labor‐intensive methods, and all, relative to the solid metals from which they derive, are expensive. Thus, one may ask if metal foams are viable. By viable a favorable balance between performance and cost is meant. Viability is assessed by constructing a value function which includes measures of both performance and cost. It allows ranking of materials by both economic and technical criteria. The authors describe progress in constructing and using cost models for two of the processes by which metal foams are made, and describe their method for assessing the viability of a new material.  相似文献   
19.
Cadmium uptake by floating macrophytes.   总被引:12,自引:0,他引:12  
M A Maine  M V Duarte  N L Su?é 《Water research》2001,35(11):2629-2634
Cd uptake capacity of a group of floating macrophytes (Salvinia herzogii, Pistia stratiotes, Hydromistia stolonifera and Eichhornia crassipes) was determined in outdoors experiments during the lowest temperature period of the year. Although all studied species were highly efficient in the Cd uptake, Pistia stratiotes was selected for further research because of its superior performance and its higher average relative growth rate. Cadmium% removal by Pistia stratiotes was greater in the first 24 h of the experiments (63, 65, 72 and 74% of the added Cd for 1, 2, 4 and 6 mg Cd 1(-1), respectively). After 31 days of growth, Pistia statiotes efficiently removed Cd at the studied concentrations. The macrophyte was able to keep its capacity for Cd removal even though some toxicity symptoms appeared at 4 and 6 mg Cd 1(-1). The greater the initial concentration, the greater Cd bioaccumulation rates. The increase of Cd concentration in plant tissues occurred especially in roots and was linearly related to the quantity of Cd added. Cd sorption by roots is faster than translocation to the plant aerial part and it occurs mainly during the first 24h.  相似文献   
20.
Although vasodilator agents have been used to alleviate the pain of complex regional pain syndromes, the precise mechanism of pain relief is not well known. In this study the effects of various kinds of vasodilators on primary afferent nociceptors were investigated by measuring the thermal pain threshold. Evaluated in the study were the effects of guanethidine (2 mg/mL), nicardipine (0.2 mg/mL). Nitroglycerin (0.3 mg/mL), and prostaglandin E1 (1 microgram/mL) on the cutaneous pain threshold and blood flow at 7-day intervals in six healthy volunteers. Each aliquot of 0.5 mL of the test vasodilator or lidocaine (10 mg/mL) and saline (control) were intradermally injected at three sites each on both forearms. The pricking-pain threshold and skin tissue blood flow were determined using a radiant heat-stimulating system and a laser-Doppler tissue-blood flowmeter, respectively. The pain threshold increased with lidocaine, guanethidine, and nicardipine; remained unchanged with Nitroglycerin; but decreased with prostaglandin E1. In contrast, the skin tissue blood flow increased by four to nine times with all vasodilators. These results indicate that the effect of vasodilators on primary afferent nociceptors is not related to the vasodilating effect and may not involve a common mechanism of action for pain relief in complex regional pain syndromes.  相似文献   
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