21 research outputs found

    Non-aqueous electrolyte solutions in chemistry and modern technology

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    In this paper a brief survey is given of the properties of non-aqueous electrolyte solutions and their applications in chemistry and technology without going into the details of theory. Specific solvent-solute interactions and the role of the solvent beyond its function as a homogenous isotropic medium are stressed. Taking into account Parker's statement1) ldquoScientists nowadays are under increasing pressure to consider the relevance of their research, and rightly sordquo we have included examples showing the increasing industrial interest in non-aqueous electrolyte solutions. The concepts and results are arranged in two parts. Part A concerns the fundamentals of thermodynamics, transport processes, spectroscopy and chemical kinetics of non-aqueous solutions and some applications in these fields. Part B describes their use in various technologies such as high-energy batteries, non-emissive electro-optic displays, photoelectrochemical cells, electrodeposition, electrolytic capacitors, electro-organic synthesis, metallurgic processes and others. Four Appendices are added. Appendix A gives a survey on the most important non-aqueous solvents, their physical properties and correlation parameters, and the commonly used abbreviations. Appendices B and C show the mathematical background of the general chemical model. The Symbols and abbreviations of the text are listed and explained in Appendix D

    Complement Activation in Relation to Capillary Leakage in Children with Septic Shock and Purpura

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    To assess the relationship between capillary leakage and inflammatory mediators during sepsis, blood samples were taken on hospital admission, as well as 24 and 72 h later, from 52 children (median age, 3.3 years) with severe meningococcal sepsis, of whom 38 survived and 14 died. Parameters related to cytokines (interleukin 6 [IL-6] IL-8, plasma phospholipase A(2), and C-reactive protein [CRP]), to neutrophil degranulation (elastase and lactoferrin), to complement activation (C3a, C3b/c, C4b/c, and C3- and C4-CRP complexes), and to complement regulation (functional and inactivated C1 inhibitor and C4BP) were determined. The degree of capillary leakage was derived from the amount of plasma infused and the severity of disease by assessing the pediatric risk of mortality (PRISM) score. Levels of IL-6, IL-8, C3b/c, C3-CRP complexes, and C4BP on admission, adjusted for the duration of skin lesions, were significantly different in survivors and nonsurvivors (C3b/c levels were on average 2.2 times higher in nonsurvivors, and C3-CRP levels were 1.9 times higher in survivors). Mortality was independently related to the levels of C3b/c and C3-CRP complexes. In agreement with this, levels of complement activation products correlated well with the PRISM score or capillary leakage. Thus, these data show that complement activation in patients with severe meningococcal sepsis is associated with a poor outcome and a more severe disease course. Further studies should reveal whether complement activation may be a target for therapeutical intervention in this disease

    In transit metastases of malignant melanoma treated by high dose rTNFα in combination with interferon-γ and melphalan in isolation perfusion

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    To increase the therapeutic efficacy of recombinant tumor necrosis factor alpha (rTNFα) and reduce the systemic side effects, a protocol was designed using isolation perfusion of the limbs with hyperthermia for in transit metastases of melanoma. A triple combination of high dose rTNFα + recombinant interferon-gamma (rIFN-γ) + melphalan was chosen because of a synergistic anti-tumor effect of rTNFα with rIFN-γ and of rTNFα with alkylating agents reported in the literature. Twenty-nine patients of mean age 60 years (range 22-82 years) entered the study after informed consent and received a total of 31 isolation perfusions with the triple combination. There were 24 women and 5 men with multiple progressive in transit melanoma metastases of the lower limb (stage IIIa or IIIab). rTNFα at the unique dose of 4 mg was injected as a bolus in the arterial line, under mild hyperthermic conditions (40 to 40.5°C) for 90 minutes. rIFN-γ was given subcutaneously on days -2 and -1 and in the perfusate, with rTNFα, at the dose of 0.2 mg. Melphalan was administered in the perfusate at dose giving a concentration of 40 μg/ml. In all the 31 isolation perfusions performed in the triple combination protocol, in order to prevent a septic shock-like syndrome which had been encountered in 2 patients treated outside this protocol for sarcoma and carcinoma, the patients received dopamine continuous infusion at 3 μg/kg/min from the start of isolation perfusion and for 48 hours, and only showed mild hyptension and very transient chills and temperature. Regional toxicity attributable to rTNFα was minimal. There have been 16 patients with hematologic toxicity consisting of neutropenia (11 cases, 1 case grade 4 and 1 case grade 3) and neutropenia with thrombocytopenia (12 cases, 1 case grade 4 and 4 cases grade 2). Eighteen of 29 patients had been previously treated with melphalan in isolation perfusion (n=13) or with cisplatinum (n=2), rTNFα-Melphalan (n=1), or rTNFα alone (n=2). Median follow-up has been 41 weeks. The 29 patients are evaluable: there have been 26 (90%) complete remissions (CR), 3 (10%) partial remissions (PR), and no failures. Actuarial disease-free survival and total survival have been 63% and 73%, respectively, at 12 months. In all cases, softening of the nodules was obvious within 3 days after isolation perfusion and time to definite response ranged between day 6 and 22. This interim analysis of a phase II study suggests that high dose of rTNFα can be administered with acceptable toxicity by isolation perfusion with dopamine and hyperhydration. Tumor responses can be evidenced in all patients, with 90% CR. Furthermore, combination of rTNFα, rIFN-γ, and melphalan seems to achieve high efficacy with minimal toxicity, even after failure of prior therapy with melphalan alone. © 1992 the Société Internationale de Chirurgie.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

    Measurement Issues in Health Disparities Research

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    BACKGROUND: Racial and ethnic disparities in health and health care have been documented; the elimination of such disparities is currently part of a national agenda. In order to meet this national objective, it is necessary that measures identify accurately the true prevalence of the construct of interest across diverse groups. Measurement error might lead to biased results, e.g., estimates of prevalence, magnitude of risks, and differences in mean scores. Addressing measurement issues in the assessment of health status may contribute to a better understanding of health issues in cross-cultural research. OBJECTIVE: To provide a brief overview of issues regarding measurement in diverse populations. FINDINGS: Approaches used to assess the magnitude and nature of bias in measures when applied to diverse groups include qualitative analyses, classic psychometric studies, as well as more modern psychometric methods. These approaches should be applied sequentially, and/or iteratively during the development of measures. CONCLUSIONS: Investigators performing comparative studies face the challenge of addressing measurement equivalence, crucial for obtaining accurate results in cross-cultural comparisons
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