548 research outputs found

    CATT behandeling aardbei(moeder)planten tegen plantparasitaire nematoden

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    In de vermeerdering van aardbeiplanten, maar ook in de productieteelt van aardbeien kunnen plant parasitaire nematoden veel schade veroorzaken. Met schoon uitgangsmateriaal op aaltjesvrije grond wordt populatieopbouw voorkomen en inzet van chemische grondontsmettingsmiddelen sterk gereduceerd. Een aangepaste CATT (Controlled Atmosphere Temperature Treatment) behandeling tegen aardbeimijt blijkt ook werkzaam te zijn tegen de plantparasitaire aaltjes P. penetrans en M. hapla. De vraag is of door een geoptimaliseerde CATT behandeling besmet plantmateriaal voldoende vrij kan worden gemaakt van deze nematoden

    Construyendo Cadenas de Valor Incluyentes: una comparación de dos casos de biocomercio en Suramérica

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    Este artículo analiza la configuración de redes de innovación en dos casos de cadenas de valor de biocomercio en Suramérica: producción de salsas de ajíes con frutas amazónicas en Colombia y producción de perfumes en Brasil a partir de aceites esenciales provenientes de Ecuador. Por medio de la integración de dos perspectivas teóricas, los autores resaltan tanto los aspectos económicos como socioculturales que influencian la configuración de estas redes. Esto permite considerar las tensiones, sinergias y contradicciones entre las lógicas del mercado y las prácticas, significados y valores socioculturales locales. Sacando lecciones aprendidas de los estudios de caso, el artículo contribuye a la discusión teórica sobre cómo las cadenas de valor (incluyentes) son social y económicamente construidas, y cómo su desempeño está relacionado con las redes de innovación

    A Snapshot of the International Views of the Treatment of Rectal Cancer Patients, a Multi-regional Survey: International Tendencies in Rectal Cancer

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    BACKGROUND: Management of rectal cancer has a number of potentially appropriate alternatives for each patient. Despite acceptance of standards, practices may vary among regions. There is significant paucity of data in this area. The objective was to create a snapshot of the regional differences. DESIGN: This online survey included 10 questions. Enquiries focused on controversial topics, on surgeon and hospital volume, surgical margins, appropriateness of surgical approaches and techniques, watch-and-wait strategies, and total neoadjuvant therapy. Major colorectal surgery societies around the world were asked to invite their members to complete the survey. OUTCOME MEASURES: Frequency of responses across regions within each question was compared by Fisher's exact test. RESULTS: Seven hundred and fifty-three participants from 60 countries responded. Eight regions were identified, and four had sufficient representation for comparisons. Similarities and differences in the therapies among these regions were identified. Robotic surgery penetrance is higher in North America, and watch and wait is more accepted in South America. Patients in Oceania are more likely to be diverted; Europe has more usage of taTME. DISCUSSION: This online survey was practical as a mean to provide a rapid assessment of the international picture on consistency and variability of rectal cancer patients' care, and to potentially identify opportunities to standardized care to patients. Medical surveys have inherent limitations; pertinence to our study is selection bias. CONCLUSIONS: The management of rectal cancer varies among different regions. Identification of differences is important when considering global efforts to improve management and interpret data

    Development of a dynamic myocardial perfusion phantom model for tracer kinetic measurements

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    BACKGROUND: Absolute myocardial perfusion imaging (MPI) is beneficial in the diagnosis and prognosis of patients with suspected or known coronary artery disease. However, validation and standardization of perfusion estimates across centers is needed to ensure safe and adequate integration into the clinical workflow. Physical myocardial perfusion models can contribute to this clinical need as these can provide ground-truth validation of perfusion estimates in a simplified, though controlled setup. This work presents the design and realization of such a myocardial perfusion phantom and highlights initial performance testing of the overall phantom setup using dynamic single photon emission computed tomography. RESULTS: Due to anatomical and (patho-)physiological representation in the 3D printed myocardial perfusion phantom, we were able to acquire 22 dynamic MPI datasets in which 99mTc-labelled tracer kinetics was measured and analyzed using clinical MPI software. After phantom setup optimization, time activity curve analysis was executed for measurements with normal myocardial perfusion settings (1.5 mL/g/min) and with settings containing a regional or global perfusion deficit (0.8 mL/g/min). In these measurements, a specific amount of activated carbon was used to adsorb radiotracer in the simulated myocardial tissue. Such mimicking of myocardial tracer uptake and retention over time satisfactorily matched patient tracer kinetics. For normal perfusion levels, the absolute mean error between computed myocardial blood flow and ground-truth flow settings ranged between 0.1 and 0.4 mL/g/min. CONCLUSION: The presented myocardial perfusion phantom is a first step toward ground-truth validation of multimodal, absolute MPI applications in the clinical setting. Its dedicated and 3D printed design enables tracer kinetic measurement, including time activity curve and potentially compartmental myocardial blood flow analysis
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