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排序方式: 共有723条查询结果,搜索用时 31 毫秒
41.
We present an epidemiological model applicable to insulin-dependent diabetes mellitus (IDDM), based on which prevalence rates are estimated from assumed rates of incidence and mortality of diabetes. The model is illustrated by analysing epidemiological data on IDDM in Fyn County, Denmark for the period 1970-1990, with predictions of prevalence rates during 1990-2020. The epidemiological model assumes known prevalence rates as well as incidence rates and mortality at a given point of time. Under assumed rates of incidence and mortality of IDDM and its complications, the prevalence rate is the dependent variable which is estimated as a function of calendar time. We used epidemiological data on IDDM (operationally defined as insulin-treated diabetes with onset before age 30 years), blindness and nephropathy as well as mortality as reported for the years 1973 and 1987 in Fyn County, Denmark. During 1970-1990 the prevalence of IDDM increased steadily, due to increasing incidence and decreasing risk of complications and mortality. The relative prevalence of patients with nephropathy increased whereas that of blind patients decreased considerably. Under specified assumptions regarding the future levels of incidence of disease, complications and of mortality, it is estimated that the prevalence rate of IDDM in the year 2020 will be 45-60% higher than the level in 1990. The relative prevalence of patients with nephropathy will increase further, whereas the relative prevalence of blind patients will remain constant at a low level. We conclude that IDDM will represent an increasing public health problem in Denmark over the next decades, with increasing overall prevalence rates and a rising proportion of patients with nephropathy. The major determinants of this trend are increasing incidence, combined with declining mortality and declining risk of complications. It is recommended that epidemiological modelling techniques be further developed to provide improved data for the planning of the future diabetes care. 相似文献
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43.
Responds to the reply by L. T. Hoshmand and J. Martin (see record 1997-02285-002) to S. C. Yanchar and K. B. Kristensen's comments (see record 1997-02285-001) on Hoshmand and Martin's (see record 1995-28533-001) proposal for a naturalistic epistemological approach to psychological science. Hoshmand and Martin argue that in Yanchar and Kristensen's stance toward some aspects of their proposal, they have attributed to Hoshmand and Martin a relationship between theory, method, and data that they do not hold. According to Hoshmand and Martin, in making their case Yanchar and Kristensen have objected to empirical means of evaluation, and essentially undermined their own argument. The authors clarify their position by responding to these claims. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
44.
Sjödin A McGahee EE Focant JF Jones RS Lapeza CR Zhang Y Patterson DG 《Analytical chemistry》2004,76(15):4508-4514
A semiautomated extraction and cleanup method has been developed to measure eight polybrominated diphenyl ethers (PBDEs), 2,2',4,4',5,5'-hexabromobiphenyl (BB-153), and 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153). The method employs solid-phase dispersion on diatomaceous earth in a solid-phase extraction cartridge followed by automated addition of internal standards ((13)C-labeled). Extraction is then performed using an automated modular solid-phase extraction system. The extraction procedure includes drying the sample on diatomaceous earth by pressurized nitrogen and eluting target analytes and lipids with dichloromethane. Lipid content is determined gravimetrically. Lipid determinations performed using this method are compared with other standard methods and with a certified reference material. A relative standard deviation of 7.9% was obtained for 130 determinations of the lipid content in a breast milk quality control sample. Final analytical determination of target analytes was performed by gas chromatography-isotope dilution high-resolution mass spectrometry. Relative standard deviations for the measurements of target analytes for which a labeled internal standard was available were below 10% for analytes at concentrations above 1 ng/g of lipid. Mean recoveries of the (13)C-labeled internal standards ranged from 60 to 89% for the eight PBDE congeners; 74 and 113% were recovered for BB-153 and CB-153, respectively. 相似文献
45.
A setup for the coupling of a thin-layer electrochemical flow cell to electrospray mass spectrometry
A novel setup for the coupling of a commercially available thin-layer cell to electrospray mass spectrometry (ESI-MS) which allows the electrochemical reactions at the counter electrode to be straightforwardly separated from the flow into the mass spectrometer has been developed. In this way, interferences from reaction products formed at the counter electrode can be minimized. This reduces the risk of changes in the mass spectra as a result of electrochemical reactions in the solution. The described setup also enables the working electrode to be positioned close to the electrospray (ESI) emitter without the need for a grounding point or a long transfer line between the electrochemical cell and the electrospray emitter. By decoupling the electrochemical reactions in the flow cell and those in the electrospray emitter, improved facilities for studies of electrochemical reactions are obtained through a better control of the potential of the working electrode. The setup has been used to study the oxidation of a drug (Olsalazine), which previously has been found to involve chemical follow-up reactions. It is also demonstrated that uncharged thiols can be detected in ESI-MS after spontaneous adsorption on a gold working electrode, followed by oxidative desorption to yield sulfinates or sulfonates. This adsorption and potential-controlled desorption has been used for the preconcentration of micromolar concentrations of 1-hexanethiol as well as for desalting of solutions containing micromolar concentrations of thiols. The results indicate that the present on-line coupling of an electrochemical cell to ESI-MS provides promising possibilities for sample preconcentration, matrix exchange (including desalting), and ionization of neutral compounds, such as thiols. 相似文献
46.
J Sj?vall 《Canadian Metallurgical Quarterly》1977,5(5):313-321
In an open multicentre study of bacampicillin (Penglobe), a new orally well absorb ed prodrug of ampicillin, 516 patients with acute exacerbations of chronic bronchitis or pneumonia were treated by a group of Belgian pneumologists or internists. Bacampicillin was given in a dosage regimen of 400 mg or 800 mg three times daily. In patients with acute exacerbations of chronic bronchitis the clinical success rate was high, over 95% in both groups. An improvement in the sputum purulence score was seen in 93% of the patients with an initially purulent sputum and 69% had a normal mucoid sputum at follow-up. The clinical success rate in patients with pneumonia was also similar in both dosage groups with success rates over 96%. The total number of patients with adverse reactions was not more than 5-4%, of which the majority were considered mild or moderate. Each type of side-effect occurred in a frequency of 1-2% or less. There were no differences between the two dosage regiments as regards the frequency of side-effects indicates a remarkably good tolerance of bacampicillin also with the higher dosage. 相似文献
47.
48.
Jon Gabrielsson Michael Sjöström Nils-Olof Lindberg Ann-Christin Pihl Torbjörn Lundstedt 《Drug development and industrial pharmacy》2013,39(3):297-307
ABSTRACTA total of 45 experiments were carried out to evaluate the robustness of two similar tablet formulations—a product of two strengths—with respect to normal batch-to-batch variation of the excipients and the active pharmaceutical ingredient. The formulations consist of 10 ingredients. Because of the differing amounts of active pharmaceutical ingredients, the two formulations also differ in the amounts of two of the diluents and one of the binders. The excipients and active pharmaceutical ingredient were characterized in terms of multiple variables, and principal properties were calculated with principal component analysis. A Plackett and Burman design was applied to the principal properties. The relationships between the design factors and two responses, mean disintegration time and mean crushing strength, were evaluated by using regression methods. Both formulations were found to be robust under controlled conditions. 相似文献
49.
Klas Engvall Henrik Kusar Krister Sjöström Lars J. Pettersson 《Topics in Catalysis》2011,54(13-15):949-959
The depletion of fossil fuel-based resources and concerns for increasing emissions of CO2 call for new ways of producing environmentally-friendly substitutes for motor fuels and chemicals. Thermo-chemical conversion of biomass and waste using gasification is a strong candidate to meet these challenges. For efficient and cost-effective application of this technique, novel solutions for hot gas cleaning are needed. This review highlights some important areas for improvement of upgrading technologies for pressurised fluidised bed gasification systems using biomass as a fuel. 相似文献
50.
Inclusions in commercial low and medium carbon ferromanganese 总被引:1,自引:0,他引:1
Thobias Sjöqvist Pär Jönsson Öystein Grong 《Metallurgical and Materials Transactions A》2001,32(5):1049-1056
The microstructures of commercial low and medium carbon ferromanganese have been studied by optical microscopy and electron
microprobe techniques. Element analysis and mapping have been performed on impurities in the matrix and nonmetallic inclusions
present. The results show that the most common nonmetallic inclusion is managanese oxide, followed by complex compounds of
managanese oxide, silicon oxide, and manganese sulfide. The different inclusions have been assessed according to the SS 111116
method. It follows that over 85 pct of the present nonmetallic inclusions are manganese oxides and that the amount of manganese
oxide inclusions is inversely proportional to the carbon content in standard refined ferromanganese. 相似文献