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1.
Langmuir ; 40(2): 1185-1194, 2024 Jan 16.
Article de Anglais | MEDLINE | ID: mdl-38166415

RÉSUMÉ

Unraveling the two-dimensional (2D) structural ordering of colloidal particles assembled at a flat surface is essential for understanding and optimizing their physical properties. So far, grazing-incidence small-angle X-ray scattering (GISAXS) has been widely used to determine crystallographic information on 2D self-assembled structures of nanosize objects. However, solving the structure of 2D lattices consisting of micrometer (µm)-sized objects still remains a challenge using scattering methods. Here, a model 2D SCALMS (supported catalytically active liquid metal solution) template is fabricated from µm-sized polystyrene (PS) spheres that form a monolayer on top of the flat solid support. GISAXS patterns of the sample were collected for rotation angles around its surface normal in steps of 3°. For every rotation angle, different Bragg-type interference maxima along the out-of-plane (qz) direction were observed. On the basis of simulations of GISXAS patterns of single domains of ordered particle arrangements using the distorted wave Born approximation (DWBA) and validation against a simple geometrical scattering model, the interference maxima could nicely be interpreted to originate from a monolayer of the µm-sized spherical particles which are arranged in domains of hexagonal 2D paracrystalline order. This novel GISAXS evaluation technique serves as a proof of principle for determining the µm-size periodicity of 2D crystalline domains and demonstrates its potential to spatially resolve the relative orientations of such domains with respect to a reference direction.

2.
Nanoscale ; 12(45): 22952-22957, 2020 Nov 26.
Article de Anglais | MEDLINE | ID: mdl-33196715

RÉSUMÉ

We present photocatalytically active, stable polymer-amorphous-MoS3-nanoparticle hybrid structures in aqueous solution. Below 10 nm MoS3 particles in the polymer exhibit an up to 7.5-fold increased photocatalytic activity compared to the neat nanoparticles without any additional photosensitizer. Supramolecular interactions are key in directing the structure formation of the hybrid assembly. The hybrid structures bear potential as novel affordable photocatalysts for solar energy conversion.

4.
Phys Rev Lett ; 123(21): 217201, 2019 Nov 22.
Article de Anglais | MEDLINE | ID: mdl-31809154

RÉSUMÉ

While the usual approach to tailor the behavior of condensed matter and nanosized systems is the choice of material or finite-size or interfacial effects, topology alone may be the key. In the context of the motion of magnetic domain walls (DWs), known to suffer from dynamic instabilities with low mobilities, we report unprecedented velocities >600 m/s for DWs driven by spin-transfer torques in cylindrical nanowires made of a standard ferromagnetic material. The reason is the robust stabilization of a DW type with a specific topology by the Œrsted field associated with the current. This opens the route to the realization of predicted new physics, such as the strong coupling of DWs with spin waves above >600 m/s.

5.
J Environ Manage ; 227: 209-215, 2018 Dec 01.
Article de Anglais | MEDLINE | ID: mdl-30193210

RÉSUMÉ

Manures are important soil nutrient conditioners and source of several pathogenic bacteria that potentially contribute to groundwater and surface water pollution. The best management practices need a solid understanding of manure sources, concentrations, and strategies to limit the number of bacteria in natural soil environment. In this study, a series of soil column experiments were conducted to investigate how bacteria mobility can potentially be influenced by retention mechanisms while moving through undisturbed saturated soil. This was assessed by bacteria retention profiles and mobility indices including the maximum transported (Cmax-T) and retained (Cmax-R) concentrations, filtration coefficient (λf) and the maximum depth of bacteria transport (Zmax). Three different soil samples (sandy, loamy and silty clay loam) were enriched with three types of manures (cow, sheep, and poultry), placed on top of three soil columns (16 cm diameter, 30 cm height) with an equivalent of 10 Mg ha-1 (dry basis) summing up to a total of 36 columns. Leaching was performed under saturated steady-state conditions (i.e., 1.62 cm min-1) for a duration of 4 pore volumes. After percolation, soil columns were sliced into six 5-cm interval layers and slices were characterized for retained bacteria. Results showed irregular exponential or quasi-exponential bacteria retention profiles for cow and sheep manures, whereas uniform-shaped profiles occurred for poultry manure. The latter variant also switched to exponential shape for the sandy soil at the highest and lowest Cmax-T and Cmax-R values due to higher pore water velocity. The λf and the Zmax values were also found to be affected by soil texture and manure origin. The λf was higher for poultry manure due to higher free-cell transport of bacteria most probably induced by higher amount of soluble mobile components. However, the greater amounts of transported wooden materials released from cow and sheep manures acted as harbors for bacteria. Accordingly, the filtration rate decreased and tailing effects for bacteria transport increased. The results also suggest that the practices and strategies for using manures could be optimized according to the respective transport behavior to manage the bacteria retention with respect to soil and manure types to reduce soil and water pollution.


Sujet(s)
Enterobacteriaceae , Fèces/microbiologie , Nappe phréatique , Fumier , Animaux , Bovins , Femelle , Ovis , Sol , Polluants du sol
6.
J Dairy Sci ; 101(8): 7540-7550, 2018 Aug.
Article de Anglais | MEDLINE | ID: mdl-29859692

RÉSUMÉ

Short dry periods and their effects on milk production, reproductive performance, as well as cow and udder health have been widely studied. A dearth of information is available about the consequences of short dry periods on the residue concentrations of dry cow antibiotics in milk after calving. The objective of our study was to determine the residue concentration of a dry cow antibiotic in milk after short dry periods during the colostrum period and early lactation. Quarters of 19 dry cows were treated with an intramammary (IMM) dry cow antibiotic containing 150 mg of cefquinome on d 21, 14, and 7 before calculated calving date. One quarter of each cow did not receive treatment and served as negative control. After calving, quarter foremilk samples were collected twice daily until 21 d and once daily until 36 d after IMM dry cow treatment (i.e., end of withdrawal period). A total of 588 foremilk samples from odd milking numbers were chosen for the determination of the residue concentration of cefquinome using HPLC-tandem mass spectrometry until the residue concentration fell below the limit of quantification (1 ng/g), which occurred at the latest in milking number 37. The dry period length of the treated quarters was categorized in 3 dry period groups ranging from 1 to 7 d (4.8 ± 2.4), 8 to 14 d (11.5 ± 2.3), and 15 to 26 d (19.5 ± 3.3; ±SEM), in dry period group 1, 2, and 3, respectively. In dry period group 1, the cefquinome concentration increased after calving until the third milking and decreased considerably until the fifth milking. In dry period group 2, the cefquinome concentration peaked at the second milking and decreased considerably until the fifth milking as well. There was no increase in cefquinome after calving in dry period group 3. Up to the 37th milking, the cefquinome concentration was higher in dry period group 1 than in dry period group 2 and 3. On average, 31.3 ± 1.2, 19.0 ± 1.1, and 6.7 ± 0.8 milkings and 19.4 ± 0.4, 20.6 ± 0.5, and 24.1 ± 0.7 d after treatment were necessary for the concentration of cefquinome to fall below the maximum residue limit (MRL) in dry period group 1, 2, and 3, respectively. These results indicate that shorter dry periods lead initially to higher cefquinome residues in milk. The residue concentration after experimental short dry periods still falls below the MRL within the recommended withdrawal period for milk of 36 d after IMM dry cow treatment. For the sake of food safety and economics, these short dry periods should not be used in the dry cow management, as they lead up to a maximum of 31.3 ± 1.2 milkings and 19.4 ± 0.4 d after treatment with cefquinome residues above the MRL. Therefore, a considerable number of milkings have to be discarded due to long withdrawal periods after calving.


Sujet(s)
Antibactériens/analyse , Céphalosporines/analyse , Résidus de médicaments/analyse , Lait/composition chimique , Animaux , Bovins , Femelle , Lactation , Glandes mammaires animales , Grossesse
7.
Nanoscale ; 10(18): 8385-8390, 2018 May 10.
Article de Anglais | MEDLINE | ID: mdl-29696279

RÉSUMÉ

Preparation of pre-patterned alumina substrates using bottom-up techniques compatible with nanotechnology applications is still a challenge. We present a novel methodology to achieve superior order in 'anodic' alumina with large interpore distances by a convenient one-step anodization process. The use of transparent insulators renders such anodic layers applicable as templates for nanostructured photovoltaic or photoelectrochemical devices.

8.
J Environ Manage ; 201: 388-396, 2017 Oct 01.
Article de Anglais | MEDLINE | ID: mdl-28697382

RÉSUMÉ

A precise evaluation of bacteria transport and mathematical investigations are useful for best management practices in agroecosystems. In this study, using laboratory experiments and modeling approaches, we assess the transport of bacteria released from three types of manure (cow, sheep, and poultry) to find the importance of the common manures in agricultural activities in soil and water pollution. Thirty six intact soil columns with different textures (sandy, loamy, and silty clay loam) were sampled. Fecal coliform leaching from layers of the manures on the soil surface was conducted under steady-state saturated flow conditions at 20 °C for up to four Pore Volumes (PVs). Separate leaching experiments were conducted to obtain the initial concentrations of bacteria released from the manures (Co). Influent (Co) and effluent (C) bacteria concentrations were measured by the plate-count method and the normalized concentrations (C/C0) were plotted versus PV representing the breakthrough curves (BTCs). Transport parameters were predicted using the attachment/detachment model (two-kinetic site) in HYDRUS-1D. Simulations fitted well the experimental data (R2 = 0.50-0.96). The attachment, detachment, and straining coefficients of bacteria were more influenced by the soils treated with cow manure compared to the sheep and poultry manures. Influent curves of fecal coliforms from the manures (leached without soil) illustrated that the poultry manure had the highest potential to pollute the effluent water from the soils in term of concentration, but the BTCs and simulated data related to the treated soils illustrated that the physical shape of cow manure was more important to both straining and detachment of bacteria back into the soil solution. Detachment trends of bacteria were observed through loam and silty clay loam soils treated with cow manure compared to the cow manure enriched sandy soil. We conclude that management strategies must specifically minimize the effect of fecal coliform concentrations before field application, especially for the combination of poultry and cow manures, which has higher solubility and tailing behavior, respectively. Interestingly, the addition of sheep manure with all three soils had the lowest mobilization of bacteria. We also suggest studying the chemistry of soil solution affected by manures to present all relevant information which affect bacterial movement through soils during leaching.


Sujet(s)
Agriculture , Fumier , Polluants du sol , Animaux , Bovins , Femelle , Ovis , Sol
9.
BMC Cancer ; 17(1): 130, 2017 02 14.
Article de Anglais | MEDLINE | ID: mdl-28193264

RÉSUMÉ

BACKGROUND: Despite our growing knowledge about the pathomechanisms of cancer cachexia, a whole clinical picture of the cachectic patient is still missing. Our objective was to evaluate the clinical characteristics in cancer patients with and without cachexia to get the whole picture of a cachectic patient. METHODS: Cancer patients of the University Clinic "Klinikum rechts der Isar" with gastrointestinal, gynecological, hematopoietic, lung and some other tumors were offered the possibility to take part in the treatment concept including a nutrition intervention and an individual training program according to their capability. We now report on the first 503 patients at the time of inclusion in the program between March 2011 and October 2015. We described clinical characteristics such as physical activity, quality of life, clinical dates and food intake. RESULTS: Of 503 patients with cancer, 131 patients (26.0%) were identified as cachectic, 369 (73.4%) as non-cachectic. The change in cachexia were 23% reduced capacity performance (108 Watt for non-cachectic-patients and 83 Watt for cachectic patients) and 12% reduced relative performance (1.53 Watt/kg for non-cachectic and 1.34 Watt/kg for cachectic patients) in ergometry test. 75.6% of non-cachectic and 54.3% of cachectic patients still received curative treatment. CONCLUSION: Cancer cachectic patients have multiple symptoms such as anemia, impaired kidney function and impaired liver function with elements of mild cholestasis, lower performance and a poorer quality of life in the EORTC questionnaire. Our study reveals biochemical and clinical specific features of cancer cachectic patients.


Sujet(s)
Cachexie/thérapie , Tumeurs/complications , Techniques de physiothérapie , Qualité de vie/psychologie , Anémie/étiologie , Cachexie/épidémiologie , Cachexie/étiologie , Cachexie/psychologie , Consommation alimentaire , Exercice physique , Femelle , Humains , Rein/physiopathologie , Foie/physiopathologie , Tests de la fonction hépatique , Mâle , Tumeurs/physiopathologie , État nutritionnel
10.
Blood Cancer J ; 5: e348, 2015 Sep 18.
Article de Anglais | MEDLINE | ID: mdl-26383821

RÉSUMÉ

Bispecific antibodies (bsAbs) engaging T cells are emerging as a promising immunotherapeutic tool for the treatment of hematologic malignancies. Because their low molecular mass, bsAbs have short half-lives. To achieve clinical responses, they have to be infused into patients continously, for a long period of time. As a valid alternative we examined the use of mesenchymal stromal cells (MSCs) as autonomous cellular machines for the constant production of a recently described, fully humanized anti-CD33-anti-CD3 bsAb, which is capable of redirecting human T cells against CD33-expressing leukemic cells. The immortalized human MSC line SCP-1 was genetically modified into expressing bsAb at sufficient amounts to redirect T cells efficiently against CD33 presenting target cells, both in vitro and in an immunodeficient mouse model. Moreover, T cells of patients suffering from acute myeloid leukemia (AML) in blast crisis eliminated autologous leukemic cells in the presence of the bsAb secreting MSCs over time. The immune response against AML cells could be enhanced further by providing T cells an additional co-stimulus via the CD137-CD137 ligand axis through CD137L expression on MSCs. This study demonstrates that MSCs have the potential to be used as cellular production machines for bsAb-based tumor immunotherapy in the future.


Sujet(s)
Anticorps bispécifiques/biosynthèse , Immunothérapie/méthodes , Leucémie aigüe myéloïde/thérapie , Transplantation de cellules souches mésenchymateuses/méthodes , Cellules souches mésenchymateuses/immunologie , Animaux , Anticorps bispécifiques/usage thérapeutique , Antigènes CD3/immunologie , Lignée cellulaire tumorale , Cytométrie en flux , Humains , Leucémie aigüe myéloïde/immunologie , Activation des lymphocytes/immunologie , Souris , Souris de lignée NOD , Souris SCID , Lectine-3 de type Ig liant l'acide sialique/immunologie , Lymphocytes T/immunologie , Tests d'activité antitumorale sur modèle de xénogreffe
11.
Med Oncol ; 32(7): 204, 2015 Jul.
Article de Anglais | MEDLINE | ID: mdl-26071123

RÉSUMÉ

In the last years, the impact of weight loss in patients with malignant tumors has come more and more into the focus of clinical research, as the occurrence of weight loss is often associated with a reduced survival. Weight loss can be a hint for metastases in patients suffering from malignant tumors; furthermore, these patients are usually not able to be treated with chemotherapy. The aim of the study was to show the influence of weight loss and an elevated nutrition risk score on survival following tumor resection in patients suffering from gastric cancer. In 99 patients in whom a gastrectomy due to gastric cancer was performed, the nutrition risk score was calculated and its influence on mortality, morbidity and survival was analyzed. Of the included patients, 45 % of the patients gave a history of weight loss; they had significantly more often a NRS ≥ 3. In UICC stage 1a/b, a NRS ≥ 3 was associated with a significantly reduced survival compared to patients with a NRS < 3. In early tumor stages (UICC 1a/b), a NRS ≥ 3 was associated with a significantly reduced survival, while in progressed tumor stage, the influence of a poor NRS was not significant. This seems to show that in progressed stages in patients with gastric cancer, the influence of a reduced NRS is negligible.


Sujet(s)
Gastrectomie/effets indésirables , État nutritionnel/physiologie , Tumeurs de l'estomac/mortalité , Tumeurs de l'estomac/anatomopathologie , Sujet âgé , Femelle , Humains , Mâle , Adulte d'âge moyen , Stadification tumorale/méthodes , Facteurs de risque , Tumeurs de l'estomac/chirurgie , Perte de poids/physiologie
12.
Scand J Surg ; 104(3): 176-84, 2015 Sep.
Article de Anglais | MEDLINE | ID: mdl-25231956

RÉSUMÉ

BACKGROUND AND AIMS: In spite of huge developments in liver surgery during the last decades, morbidity and mortality continue to pose problems in this field. The aim of this study was to identify preoperative predictors for postoperative mortality and morbidity in liver surgery. MATERIAL AND METHODS: In a single-center study, an extensive analysis of a prospective database, including clinical criteria and laboratory tests of patients undergoing liver surgery between July 2007 and July 2012 was performed. Cutoff values of selected laboratory tests were calculated. RESULTS: In all, 337 patients were included in the study. Univariate analysis showed a statistically significant association of preoperative bilirubin, lactate, hemoglobin levels, platelet count, and prothrombin time with postoperative morbidity and mortality. Multivariate analysis revealed preoperatively elevated serum bilirubin and lactate levels as independent predictors for increased postoperative morbidity and mortality after liver surgery. CONCLUSIONS: The identified laboratory values showed a statistically significant association with postoperative morbidity and mortality in liver surgery and might be helpful in preoperative patient selection.


Sujet(s)
Bilirubine/sang , Hépatectomie/effets indésirables , Acide lactique/sang , Maladies du foie/sang , Maladies du foie/mortalité , Adulte , Sujet âgé , Sujet âgé de 80 ans ou plus , Études de cohortes , Femelle , Hépatectomie/mortalité , Humains , Maladies du foie/chirurgie , Mâle , Adulte d'âge moyen , Valeur prédictive des tests , Résultat thérapeutique , Jeune adulte
13.
Int J Surg ; 12(10): 1025-30, 2014 Oct.
Article de Anglais | MEDLINE | ID: mdl-25192805

RÉSUMÉ

INTRODUCTION: The standard treatment concept in patients with locally advanced adenocarcinoma of the esophagogastric junction is neoadjuvant chemotherapy, followed by tumor resection in curative intent. Response evaluation of neoadjuvant chemotherapy using histopathological tumor regression grade (TRG) has been shown to be a prognostic factor in patients with esophageal cancer. METHODS: We assessed the impact of the various methods of response control and their value in correlation to established prognostic factors in a cohort of patients with adenocarcinoma at the gastroesophageal junction treated by neoadjuvant chemotherapy. RESULTS: After neoadjuvant chemotherapy, in 56 consecutive patients with locally advanced (T2/3/4 and/or N0/N1) esophageal adenocarcinoma an oncologic tumor resection for curative intent was performed. Median follow-up was 44 months. Histopathological tumor stages were stage 0 in 10.7%, stage I in 17.9%, stage II in 21.4%, stage III in 41.1% and stage IV 8.9%. The 3-year overall survival (OS) rate was 30.3%. In univariate analysis, ypN-status, histopathological tumor stage and tumor regression grade correlated significantly with overall survival (p = 0.022, p = 0.001, p = 0.035 respectively). Clinical response evaluation could not predict response and overall survival (p = 0.556, p = 0.254 respectively). CONCLUSION: After preoperative chemotherapy, outcomes of esophageal carcinoma are best predicted utilizing pathological tumor stage and histologic tumor regression. Clinical response assessments were not useful for guidance of treatment.


Sujet(s)
Adénocarcinome/mortalité , Adénocarcinome/thérapie , Tumeurs de l'oesophage/mortalité , Tumeurs de l'oesophage/thérapie , Jonction oesogastrique/anatomopathologie , Adénocarcinome/anatomopathologie , Sujet âgé , Anastomose chirurgicale , Traitement médicamenteux adjuvant , Études de cohortes , Tumeurs de l'oesophage/anatomopathologie , Oesophagectomie , Jonction oesogastrique/chirurgie , Femelle , Gastrectomie , Humains , Mâle , Adulte d'âge moyen , Traitement néoadjuvant , Récidive tumorale locale , Pronostic , Études rétrospectives
15.
Math Biosci ; 246(2): 293-304, 2013 Dec.
Article de Anglais | MEDLINE | ID: mdl-23602931

RÉSUMÉ

In this work we present results of a detailed Bayesian parameter estimation for an analysis of ordinary differential equation models. These depend on many unknown parameters that have to be inferred from experimental data. The statistical inference in a high-dimensional parameter space is however conceptually and computationally challenging. To ensure rigorous assessment of model and prediction uncertainties we take advantage of both a profile posterior approach and Markov chain Monte Carlo sampling. We analyzed a dynamical model of the JAK2/STAT5 signal transduction pathway that contains more than one hundred parameters. Using the profile posterior we found that the corresponding posterior distribution is bimodal. To guarantee efficient mixing in the presence of multimodal posterior distributions we applied a multi-chain sampling approach. The Bayesian parameter estimation enables the assessment of prediction uncertainties and the design of additional experiments that enhance the explanatory power of the model. This study represents a proof of principle that detailed statistical analysis for quantitative dynamical modeling used in systems biology is feasible also in high-dimensional parameter spaces.


Sujet(s)
Théorème de Bayes , Modèles biologiques , Facteurs de transcription STAT/physiologie , Transduction du signal/physiologie , Kinase Janus-2/physiologie , Chaines de Markov , Méthode de Monte Carlo , Biologie des systèmes/méthodes
16.
Leukemia ; 26(4): 728-35, 2012 Apr.
Article de Anglais | MEDLINE | ID: mdl-22015771

RÉSUMÉ

Constitutive tyrosine kinase activation by reciprocal chromosomal translocation is a common pathogenetic mechanism in chronic myeloproliferative disorders. Since centrosomal proteins have been recurrently identified as translocation partners of tyrosine kinases FGFR1, JAK2, PDGFRα and PDGFRß in these diseases, a role for the centrosome in oncogenic transformation has been hypothesized. In this study, we addressed the functional role of centrosomally targeted tyrosine kinase activity. First, centrosomal localization was not routinely found for all chimeric fusion proteins tested. Second, targeting of tyrosine kinases to the centrosome by creating artificial chimeric fusion kinases with the centrosomal targeting domain of AKAP450 failed to enhance the oncogenic transforming potential in both Ba/F3 and U2OS cells, although phospho-tyrosine-mediated signal transduction pathways were initiated at the centrosome. We conclude that the centrosomal localization of constitutively activated tyrosine kinases does not contribute to disease pathogenesis in chronic myeloproliferative disorders.


Sujet(s)
Transformation cellulaire néoplasique , Centrosome/physiologie , Syndromes myéloprolifératifs/complications , Protein-tyrosine kinases/physiologie , Lignée cellulaire tumorale , Maladie chronique , Humains , Phosphorylation , Récepteur au PDGF alpha/physiologie , Récepteur au PDGF bêta/physiologie , Protéines de fusion recombinantes/métabolisme , Tyrosine/métabolisme
17.
J Intern Med ; 271(2): 155-65, 2012 Feb.
Article de Anglais | MEDLINE | ID: mdl-22142263

RÉSUMÉ

Complex intracellular signalling networks integrate extracellular signals and convert them into cellular responses. In cancer cells, the tightly regulated and fine-tuned dynamics of information processing in signalling networks is altered, leading to uncontrolled cell proliferation, survival and migration. Systems biology combines mathematical modelling with comprehensive, quantitative, time-resolved data and is most advanced in addressing dynamic properties of intracellular signalling networks. Here, we introduce different modelling approaches and their application to medical systems biology, focusing on the identifiability of parameters in ordinary differential equation models and their importance in network modelling to predict cellular decisions. Two related examples are given, which include processing of ligand-encoded information and dual feedback regulation in erythropoietin (Epo) receptor signalling. Finally, we review the current understanding of how systems biology could foster the development of new treatment strategies in the context of lung cancer and anaemia.


Sujet(s)
Tumeurs du poumon/physiopathologie , Modèles biologiques , Récepteur érythropoïétine/physiologie , Transduction du signal/physiologie , Biologie des systèmes/méthodes , Anémie/induit chimiquement , Anémie/traitement médicamenteux , Antinéoplasiques/effets indésirables , Survie cellulaire/physiologie , Cytokines/métabolisme , Érythropoïétine/effets indésirables , Érythropoïétine/métabolisme , Prévision , Humains , Fonctions de vraisemblance , Tumeurs du poumon/traitement médicamenteux , Tumeurs du poumon/étiologie , Mathématiques , Récepteur érythropoïétine/antagonistes et inhibiteurs , Protéines recombinantes , Facteurs de risque , Facteurs de transcription/physiologie
18.
Environ Pollut ; 159(10): 2487-92, 2011 Oct.
Article de Anglais | MEDLINE | ID: mdl-21763042

RÉSUMÉ

Ecotoxicity data with high reliability and relevance are needed to guarantee the scientific quality of environmental risk assessments of pharmaceuticals. The main advantages of a more structured approach to data evaluation include increased transparency and predictability of the risk assessment process, and the possibility to use non-standard data. In this collaboration, between the research project MistraPharma and the German Federal Environment Agency, a new set of reporting and evaluation criteria is presented and discussed. The new criteria are based on the approaches in the literature and the OECD reporting requirements, and have been further developed to include both reliability and relevance of test data. Intended users are risk assessors and researchers performing ecotoxicological experiments, but the criteria can also be used for education purposes and in the peer-review process for scientific papers. This approach intends to bridge the gap between the regulator and the scientist's needs and way of work.


Sujet(s)
Effets secondaires indésirables des médicaments , Surveillance de l'environnement/méthodes , Polluants environnementaux/toxicité , Divulgation/normes , Écotoxicologie , Surveillance de l'environnement/normes , Polluants environnementaux/normes , Préparations pharmaceutiques/normes , Plan de recherche , Appréciation des risques/méthodes
19.
Regul Toxicol Pharmacol ; 55(3): 276-80, 2009 Dec.
Article de Anglais | MEDLINE | ID: mdl-19607869

RÉSUMÉ

The evaluation of the quality of data and their use within the review of environmental risk assessment of human as well as veterinary pharmaceuticals is described from a regulatory point of view. A definition and differentiation in three categories for the reliability of data are given. Existing criteria relating to international testing standards for categorising reliability are adopted for their use within the environmental risk assessment of pharmaceuticals. A systematic documentation of evaluating reliability for literature data as well as for experimental studies (effect and environmental fate studies) is proposed. The data quality criteria are defined in order to increase the transparency of the evaluation process in Germany and thus the quality of the environmental risk assessment of pharmaceuticals.


Sujet(s)
Effets secondaires indésirables des médicaments , Exposition environnementale/législation et jurisprudence , Surveillance de l'environnement/législation et jurisprudence , Médicaments vétérinaires/toxicité , Animaux , Exposition environnementale/effets indésirables , Surveillance de l'environnement/méthodes , Allemagne , Recommandations comme sujet , Humains , Reproductibilité des résultats , Appréciation des risques/législation et jurisprudence , Appréciation des risques/méthodes
20.
Bioinformatics ; 25(15): 1923-9, 2009 Aug 01.
Article de Anglais | MEDLINE | ID: mdl-19505944

RÉSUMÉ

MOTIVATION: Mathematical description of biological reaction networks by differential equations leads to large models whose parameters are calibrated in order to optimally explain experimental data. Often only parts of the model can be observed directly. Given a model that sufficiently describes the measured data, it is important to infer how well model parameters are determined by the amount and quality of experimental data. This knowledge is essential for further investigation of model predictions. For this reason a major topic in modeling is identifiability analysis. RESULTS: We suggest an approach that exploits the profile likelihood. It enables to detect structural non-identifiabilities, which manifest in functionally related model parameters. Furthermore, practical non-identifiabilities are detected, that might arise due to limited amount and quality of experimental data. Last but not least confidence intervals can be derived. The results are easy to interpret and can be used for experimental planning and for model reduction. AVAILABILITY: An implementation is freely available for MATLAB and the PottersWheel modeling toolbox at http://web.me.com/andreas.raue/profile/software.html. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Sujet(s)
Algorithmes , Biologie informatique/méthodes , Modèles biologiques , Probabilité
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