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1.
Cogburn D.L. Mueller M. McKnight L. Klein H. Mathiason J. 《Communications Magazine, IEEE》2005,43(12):12-14
Who should control the Internet? A dozen years after the Internet became a mass medium, this issue has continued to grow in urgency, becoming white hot in fall 2005. At the September 2005 preparatory meeting for the UN World Summit on the Information Society (WSIS), a coalition of countries criticized the United States' unilateral control of the Internet's domain name system (DNS) and proposed the establishment of a multinational Council to supervise it. This proposal emerged from the Final Report of the UN Working Group on Internet Governance. Researchers from the Internet Governance Project, a university-based consortium for policy analysis, have concluded that the United States should internationalize governance of the Internet, but in a way that avoids intrusive, centralized control. 相似文献
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The results of the thermal and catalytic reactions of lignin model compounds are used in the a priori prediction of its liquefaction. Lignin was defined probabilistically as an ensemble of single ring aromatics with substituents on each of their six ring positions. Elements in a substituent vector x1, for each ring position i, were matched into all possible combinations to describe lignin. Initial number fractions, or probabilities, for each vector element were ascertained through inspection of lignin structural data. The reaction of lignins altered the probabilities within each substituent vector, and reaction products were also calculated by matching all combinations of vector elements for each ring position. Model compound results provided the identities and rates of change of vector elements.
This simulation of lignin liquefaction predicted the yields of permanent gases, aqueous liquids, single- and two-ring phenolic products, and a carbonaceous residue. The impact of the distribution of oligomeric sizes on catalyst effectiveness was probed. 相似文献
This simulation of lignin liquefaction predicted the yields of permanent gases, aqueous liquids, single- and two-ring phenolic products, and a carbonaceous residue. The impact of the distribution of oligomeric sizes on catalyst effectiveness was probed. 相似文献
5.
Ursula Klein 《NTM》1995,3(1):167-191
E.F. Geoffroy's table of different relations (“rapports”) between different chemical substances is mainly based on empirical knowledge accumulated in 16th and 17th century metallurgy and pharmacy. The substances listed in the left half of the table were basic for the formation of salts which were produced for medical ends in the chemical-pharmaceutical practice of the 17th century. The right half of the table refers to substances and operations of metallurgy which had already been described in the metallurgical writings of the 16th century. Even Geoffroy's ordering of the substances within the columns of his table has its origin in metallurgical and pharmaceutical practice. The key concept of the conceptual framework underlying the table and its commentary is the concept of chemical compound which emerged at the end of the 17th century. Geoffroy extends the range of application of this concept, which was first limited to chemical artefacts, to include natural bodies. Eliminating the peripatetical distinction between natural bodies and chemical artefacts he formulates a new research program, consisting in the determination of the “laws” of the relations (“rapports”) between different chemical substances. 相似文献
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In Europe, the challenge of the design of third-generation cellular mobile radio systems has been taken numerous research and development activities in this field have been started. The authors try to give an overview of the European activities in this field. The article is organized in two parts. In the first part, the requirements for third-generation cellular mobile radio systems such as Universal Mobile Telecommunications System (UMTS) and Future Public Land Mobile Telecommunications System (FPLMTS), which has been named International Mobile Telecommunications after the year 2000 (IMT-2000) are presented concisely. Also, the importance and challenge of the multiple access design for such third-generation cellular mobile radio systems is explained. In the second part, numerous European research activities with focus on the multiple access design for third-generation cellular mobile radio systems are reviewed 相似文献
7.
FF Fassos J Klein D Fernandes D Matsui NF Olivieri G Koren 《Canadian Metallurgical Quarterly》1996,34(7):288-292
Recently, we demonstrated that administration of the orally active iron chelating agent deferiprone (1,2-dimethyl-3-hydroxypyrid-4-one (L1)) at 6-hour intervals results in significantly greater urinary iron excretion than that induced during administration of the drug at 12-hour intervals. That study was conducted in thalassemia patients, all of whom had received a packed red cell transfusion of 15 cc/kg. 72 hours prior to evaluation of urinary iron excretion, at a time when endogenous erythropoiesis would be expected to be at its lowest. In clinical practice however, thalassemia patients, suppression of endogenous erythropoiesis is not sustained between transfusions. We set out to determine the influence that administration of deferiprone has on urinary iron excretion at lower hemoglobin concentrations, immediately prior to transfusion. We hypothesized that hemoglobin levels will affect the ability of deferiprone to chelate iron. Ten regularly transfused patients with homozygous beta-thalassemia (HBT) aged mean +/- SD, 20.9 +/- 4.7, range 13 - 27 years, receiving long-term therapy with deferiprone, were treated with deferiprone 75 mg/kg/day, administered every 6 hours (or every 12 hours) for 72 hours immediately prior to a blood transfusion in the first month. One month later each patient received the other of the 2 dosing regimens for 72 hours immediately prior to transfusion. The deferiprone-induced 24-hour urinary iron excretion was similar during both dosing regimens; 0.56 +/- 0.45 mg/kg when L1 was given every 6 hours and 0.48 +/- 0.52 mg/kg when L1 was administered every 12 hours (p = 0.79). However, the calculated 24-hour area under the plasma concentration-time curve (AUC0-24) of deferiprone was significantly lower when deferiprone was administered at 6-hour intervals (6,762.8 +/- 1,601.6 mg*min/l), than that observed when deferiprone was administered every 12 hours (8,250.1 +/- 1,235.7 mg*min/l) (p = 0.04). The pharmacokinetics of deferiprone when administered immediately prior to transfusions are different from those following transfusions. More studies assessing total body iron excretion are needed to determine the contribution of the fecal route in iron excretion. 相似文献
8.
RM Nüsing TP Schaub T Klein H Schweer HW Seyberth 《Canadian Metallurgical Quarterly》1997,42(2):241-246
Hyperprostaglandin E syndrome (HPS), the prenatal variant of Bartter's syndrome, is characterized by a marked and selective stimulation of prostaglandin E (PGE2) synthesis. In the study group HPS patients showed increased urinary levels of PGE2, an index of renal, and of 11 alpha-hydroxy-9,15-dioxo-2,3,4,5,20-pentanor-19-carboxyprostano ic acid (PGE-M), an index of systemic PGE2 synthesis of 470% and of 570%, respectively. In addition, plasma concentration of PGE-M was also elevated 6.3-fold when compared with a control group. The urinary levels of other prostanoids were unaltered. During indomethacin treatment in both groups prostanoid excretion rates were suppressed to similar levels. To investigate the origin of stimulated prostanoid biosynthesis in HPS patients CD14+ monocytes were isolated from plasma samples, and the prostanoid synthesis was analyzed. The pattern and amounts of metabolites synthesized from endogenous arachidonic acid pools did not vary significantly between monocytes of the HPS and the control group. Thromboxane A2 (TXA2) was formed as the major prostanoid product. Using PGH2 as an exogenous substrate, again no difference in PGE2 biosynthesis was observed, indicating no difference in PGE-synthetic activity between both groups. Additionally, mRNA expression analysis of CD14+ monocytes via RT-PCR delineated the constitutive expression of cyclooxygenase-1, cyclooxygenase-2, and thromboxane synthase mRNA in cells from HPS patients and controls without statistical differences between these two groups. In conclusion, our data show that monocytes are not the source for the increased PGE2 biosynthesis in children with HPS, and a genetic defect in PGE synthesis can be excluded as the primary event in the pathogenesis in HPS. 相似文献
9.
European Food Research and Technology - Bei Bestimmungen des Proteingehalts von Haselnüssen in verschiedenen Handelsprodukten wie Nuß-Nougatcremes and Nußmus mit der... 相似文献
10.
The operation and management of the Kansas University Packet Switch Network (KUPSN),which provides interactive and file transfer services to its users, is discussed, focussing on the problems encountered and solutions developed. Areas of network management of particular concern are identified, and tools developed to deal with them are described. Management system integration and the evolution of problem-handling procedures are discussed 相似文献