102 research outputs found

    Risk is of all Time

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    Safety management theory and the military expeditionary organization: A critical theoretical reflection

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    Management of safety within organizations has become a key topic within safety science. Theorizing on this subject covers a diverse pallet of concepts such as “resilience” and “safety management systems”. Recent studies indicate that safety management theory has deficiencies. Our interpretation of these deficiencies is that much confusion originates from the issue that crucial meta-theoretical assumptions are mostly implicit or applied inconsistently. In particular, we argue that these meta-theoretical assumptions are of a systems theoretical nature. Therefore, we provide a framework that will be able to explicate and reflect on systems theoretical assumptions. With this framework, we analyze the ability of two frequently used safety management theories to tackle the problem of managing safety of Dutch military expeditionary organizations. This paper will show that inconsistent and implicit application of systems theoretical assumptions in these safety management theories results in problems to tackle such a practical problem adequately. We conclude with a reflection on the pros and cons of our framework. Also, we suggest particular meta-theoretical aspects that seem to be essential for applying safety management theory to organizations

    Comparison study on AIS data of ship traffic behavior

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    AIS (Automatic Identification System) data provides valuable input parameters in ship traffic simulation models for maritime risk analysis and the prevention of shipping accidents. This article reports on the detailed comparisons of AIS data analysis between a Dutch case and a Chinese case. This analys is focuses on restricted waterways to support inland waterway simulations, comparing the differences between a narrow waterway in the Netherlands (the Port of Rotterdam) and a wide one in China (wide water way of Yangtze River close to the SuTong Bridge). It is shown that straightforward statistical distributions can be used to characterise lateral position, speed, heading and interval times for different types and sizes of ships. However, the distributions for different characteristics of ship behaviours differ significantly

    Taal en veiligheid: een groeiend nieuw werkveld [Language and security: a growing new field of work]

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    Language issues cause safety problems at work. This study presents an inventory of scientific studies in the economic sectors and assesses which level of risk management they address. Complications with language have not been investigated comprehensively across sectors as a causal factor in accidents. This leaves language related risks partially unknown, hence uncontrolled. There is lack of insight in both the nature and magnitude of this danger in healthcare, agricultural, transport and construction sectors. Healthcare is especially troublesome since patients might be victims of language related accidents due to their presence and interaction. The same may occur to members of the public in traffic accidents. In transport and agricultural sectors safety measures were taken without any analysis of language related risks. This study shows that scientific research on ‘language and safety’ is in its infancy and requires priority on the research agenda

    Interaccion de galactooligosacáridos y lactulosa con liposomas de DPPG en estado anhidro

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    Introducción: Las membranas lipídicas son el principal foco del daño durante la deshidratación, su interacción con los azúcares juega un papel vital en el mantenimiento de su integridad estructural y su funcionamiento adecuado. La naturaleza de los carbohidratos galactooligosacáridos (GOS) y lactulosa tienen probada acción prebiótica y capacidad de actuar como protectores de bacterias lácticas expuestas a deshidratación. La principal función de un protector es regular la pérdida y el intercambio de agua de las estructuras biológicas. Estas propiedades protectoras pueden explicarse sobre la base de su capacidad para formar matrices vítreas de alta viscosidad y baja movilidad molecular, donde las interacciones moleculares están restringidas. Sin embargo, el estado vítreo es una condición necesaria pero no suficiente para explicar la capacidad protectora de los azúcares. Éstos pueden reemplazar moléculas de agua durante el secado, preservando así las estructuras y funciones fisiológicas de macromoléculas celulares, y evitar el daño bacteriano y/o la muerte en estado anhidro. La información disponible es fundamentalmente empírica y no se conocen a nivel molecular los mecanismos de interacción de estos protectores con membranas lipídicas. Objetivos: Estudiar por espectroscopia de infrarrojo por Transformadas de Fourier (FTIR) y Calorimetría Diferencial de Barrido (DSC) la interacción de (GOS) y lactulosa con los principales grupos funcionales de membranas lipídicas de dipalmitoilfosfatidilglicerol (DPPG), en estado anhidro. Resultados: Los espectros de liposomas liofilizados de DPPG previamente resuspendidos en soluciones de GOS y lactulosa al 10, 20 y 40 % p/v en H2O miliQ, se obtuvieron a diferentes temperaturas y se analizaron comparativamente con el de DPPG puro. Por FTIR la frecuencia del estiramiento antisimétrico del grupo fosfato (principal centro de hidratación) mostró desplazamiento hacia menores frecuencias. Las medidas de DSC mostraron que las interacciones de van der Waals entre las cadenas hidrocarbonadas, en los complejos oligosacáridos:DPPG, disminuyen como consecuencia de la disminución en la temperatura de transición de fase gel líquido cristalino (Tm) con respecto a la del lípido puro altamente empaquetado, en estado anhidro, a medida que aumenta el porcentaje de ambos azúcares en los sistemas GOS:DPPG y lactulosa:DPPG. . Conclusiones: Se observó reemplazo del agua estructurada en el grupo fosfato del lípido con formación de enlaces de H con ambos azúcares. La disminución de la Tm, se debería a un menor ordenamiento de las cadenas hidrocarbonadas del lípido, producida por los oligosacáridos, lo que favorecería a los liposomas de oligosacáridos:DPPG, a que sean menos propensos a la rotura y liberación, después del tratamiento de rehidratación.Fil: Ale, Norma Mercedes. Universidad Nacional de Tucuman. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Física. Cátedra de Fisicoquímica I; ArgentinaFil: Ben Altabef, Aida. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Física; ArgentinaFil: Gomez Zavaglia, Andrea. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Criotecnología de Alimentos. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Criotecnología de Alimentos; ArgentinaFil: Díaz, Sonia Beatriz. Universidad Nacional de Tucuman. Facultad de Bioquímica, Química y Farmacia. Instituto de Química Física. Cátedra de Fisicoquímica I; ArgentinaXXI Ciongreso Argentino de Fisicoquímica y Quiímica InorgánicaSan Miguel de TucumánArgentinaAsociación Argentina de Fisicoquímica y Quiímica InorgánicaUniversidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmaci

    Alendronate or alfacalcidol in glucocorticoid-induced osteoporosis

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    BACKGROUND: Treatment with glucocorticoids is associated with bone loss starting soon after therapy is initiated and an increased risk of fracture. METHODS: We performed a randomized, double-placebo, double-blind clinical trial of 18 months' duration among patients with a rheumatic disease who were starting glucocorticoids at a daily dose that was equivalent to at least 7.5 mg of prednisone. A total of 201 patients were assigned to receive either alendronate (10 mg) and a placebo capsule of alfacalcidol daily or alfacalcidol (1 mu g) and a placebo tablet of alendronate daily. The primary outcome was the change in bone mineral density of the lumbar spine in 18 months; the secondary outcome was the incidence of morphometric vertebral deformities. RESULTS: A total of 100 patients received alendronate, and 101 received alfacalcidol; 163 patients completed the study. The bone mineral density of the lumbar spine increased by 2.1 percent in the alendronate group (95 percent confidence interval, 1.1 to 3.1 percent) and decreased by 1.9 percent in the alfacalcidol group (95 percent confidence interval, -3.1 to -0.7 percent). At 18 months, the mean difference of change in bone mineral density between the two groups was 4.0 percent (95 percent confidence interval, 2.4 to 5.5 percent). Three patients in the alendronate group had a new vertebral deformity, as compared with eight patients in the alfacalcidol group (of whom three had symptomatic vertebral fractures) (hazard ratio, 0.4; 95 percent confidence interval, 0.1 to 1.4). CONCLUSIONS: During this 18-month trial in patients with rheumatic diseases, alendronate was more effective in the prevention of glucocorticoid-induced bone loss than was alfacalcidol

    Cost-effectiveness of oral anticoagulants versus aspirin in patients after infrainguinal bypass grafting surgery

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    AbstractPurpose: Several antithrombotic therapies are available for the treatment of patients with peripheral vascular diseases. It is unknown how quality of life and costs of treatment are influenced by different therapies. This study assessed the cost-effectiveness of oral anticoagulants versus aspirin in patients after infrainguinal bypass grafting surgery. Methods: Clinical outcome events and event-free survival were collected from 2650 patients in 77 centers who participated in the Dutch Bypass Oral anticoagulants or Aspirin trial. Approximately half the patients had critical ischemia; 60% received vein grafts, and 20% had femorocrural bypass grafts. A model that was primarily driven by clinical outcome events was used as a means of determining quality of life (EuroQol EQ-5D) and costs for each patient. The main outcome measure was the incremental health care costs in relation to the additional number of quality-adjusted life years and the additional number of event-free years. Results: The mean costs during the 21 months of follow-up were ϵ 6875 per patient in the oral anticoagulants group versus ϵ 7072 in the aspirin group (difference, 197; 95% CI, –746 to 343). The event-free survival was 1.10 years in the group treated with oral anticoagulants versus 1.09 years in the group treated with aspirin (difference, 0.01; 95% CI, –0.07 to 0.08), whereas the corresponding quality-adjusted life years were 1.06 and 1.05, respectively (difference, 0.01; 95% CI, –0.03 to 0.06). Conclusion: Health care costs, event-free survival, and quality-adjusted life years in patients after infrainguinal bypass surgery were not different in patients treated with aspirin and patients treated with oral anticoagulants. The extra costs of monitoring patients treated with oral anticoagulants were limited and play no role in the decision for treatment. (J Vasc Surg 2001;34:254-62.

    Interaction of glycine, lysine, proline and histidine with dipalmitoylphosphatidylcholine lipid bilayers: a theoretical and experimental study

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    The interaction of unblocked glycine, lysine, proline, and histidine (in their three forms, namely two tautomers and the protonated form) with a dipalmitoylphosphatidylcholine (DPPC) bilayer was assessed using extensive atomistic molecular dynamics simulations. Free energy profiles for the insertion of each amino acid into the lipid bilayer were computed along an appropriated reaction coordinate. The simulation results for glycine in the presence of DPPC were compared with experimental data obtained by Fourier transform infrared spectroscopy. Experimental results predict, in good agreement with simulations, the existence of intermolecular interactions between the DPPC head groups and glycine. Atomistic simulations were further extended to investigate the free energy profiles for lysine, proline and histidine, leading to the following conclusions: (i) lysine free energy profiles computed using a united atom force-field and an analog molecule, where the side-chain is truncated at the β-carbon atom, differ significantly from each other; (ii) the free energy profiles for the three forms of histidine are all very similar, although the charged form interacts mostly with the carbonyl groups of DPPC, while the tautomers interact with the phosphate groups; and (iii) proline does not show a minimum in the free energy profile, pointing to the absence of binding to the membrane lipids. Overall, this work contributes to our general understanding of the various factors affecting the interactions between amino acids and a model cell membrane, and may spur progress in the effort to develop new molecular models to study larger biological systems.Fil: Porasso, Rodolfo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Matemática Aplicada de San Luis; ArgentinaFil: Ale, Norma Mercedes. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Fisica; ArgentinaFil: Ciocco Aloia, Facundo. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Masone, Diego Fernando. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: del Popolo, Mario Gabriel. Universidad Nacional de Cuyo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Ben Altabef, Aida. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Fisica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Instituto de Quimica del Noroeste; ArgentinaFil: Gomez Zavaglia, Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico La Plata. Centro de Investigaciones en Criotecnología de Alimentos (i); ArgentinaFil: Díaz, Sonia Beatriz. Universidad Nacional de Tucuman. Facultad de Bioquimica, Quimica y Farmacia. Instituto de Quimica Fisica; ArgentinaFil: Vila, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico San Luis. Instituto de Matemática Aplicada de San Luis; Argentina. Cornell University; Estados Unido

    Ruthenacycles and Iridacycles as Catalysts for Asymmetric Transfer Hydrogenation and Racemisation

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    Ruthenacycles, which are easily prepared in a single step by reaction between enantiopure aromatic amines and [Ru(arene)Cl2]2 in the presence of NaOH and KPF6, are very good asymmetric transfer hydrogenation catalysts. A range of aromatic ketones were reduced using isopropanol in good yields with ee’s up to 98%. Iridacycles, which are prepared in similar fashion from [IrCp*Cl2]2 are excellent catalysts for the racemisation of secondary alcohols and chlorohydrins at room temperature. This allowed the development of a new dynamic kinetic resolution of chlorohydrins to the enantiopure epoxides in up to 90% yield and 98% enantiomeric excess (ee) using a mutant of the enzyme Haloalcohol dehalogenase C and an iridacycle as racemisation catalyst.

    Prevention of glucocorticoid induced osteoporosis with alendronate or alfacalcidol:Relations of change in bone mineral density, bone markers, and calcium homeostasis

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    Objective. To explore the relation of changes in measures of bone turnover and changes in bone mineral density (BMD) of the lumbar spine and total hip over 18 months in a double-blinded, randomized trial, comparing the effect of alfacalcidol (101 patients) versus alendronate (100 patients) on BMD in patients who recently started treatment with glucocorticoids for various rheumatic diseases. Methods. Associations between changes in serum procollagen type I C-propeptide (P1CP), fasting urine N-terminal telopeptide of type I collagen (NTx), serum calcium, parathyroid hormone (PTH), osteocalcin, and change from baseline in BMD over 18 months were explored with regression and correlation analyses. Results. In both treatment groups, there was a statistically significant decrease in NTx. In the alfacalcidol group there was also a significant increase in P1CP and osteocalcin, in contrast to the alendronate group, but BMD in the alfacalcidol decreased versus an increase in the alendronate group (p <0.001). In neither treatment group were changes in biochemical measures correlated with the change in BMD, with the exception of a negative correlation in the alendronate group between changes in total hip BMD and NTx. Use of alendronate resulted in an increased PTH in 27 patients, but the increase in BMD of these patients was not statistically significantly different compared to patients taking alendronate with normal PTH levels. Conclusion. Changes in BMD were not associated with changes in bone measures, with the exception of NTx in the alendronate group. For the patient taking glucocorticoids in clinical practice, the value of serial assessment of bone markers is low; changes in markers are no substitute for changes in BMD
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