213 research outputs found

    New records of hypocrealean fungi infecting aphids and whiteflies: Pathogenicity against Myzus persicae and interaction with its predator Eriopis connexa

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    Occurrence of hypocrealean entomopathogenic fungi in Argentina is reported. Bioassays were performed to evaluate their pathogenicity against Myzus persicae and Eriopis connexa. The findings underscore the importance of preserving these fungi and of investigating their potential for vector control.Fil: Scorsetti, Ana Clara. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Pelizza, Sebastian Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Estudios Parasitológicos y de Vectores. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Estudios Parasitológicos y de Vectores; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; ArgentinaFil: Cabello, Marta Noemí. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; Argentin

    Segmentation of Planning Target Volume in CT Series for Total Marrow Irradiation Using U-Net

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    Radiotherapy (RT) is a key component in the treatment of various cancers, including Acute Lymphocytic Leukemia (ALL) and Acute Myelogenous Leukemia (AML). Precise delineation of organs at risk (OARs) and target areas is essential for effective treatment planning. Intensity Modulated Radiotherapy (IMRT) techniques, such as Total Marrow Irradiation (TMI) and Total Marrow and Lymph node Irradiation (TMLI), provide more precise radiation delivery compared to Total Body Irradiation (TBI). However, these techniques require time-consuming manual segmentation of structures in Computerized Tomography (CT) scans by the Radiation Oncologist (RO). In this paper, we present a deep learning-based auto-contouring method for segmenting Planning Target Volume (PTV) for TMLI treatment using the U-Net architecture. We trained and compared two segmentation models with two different loss functions on a dataset of 100 patients treated with TMLI at the Humanitas Research Hospital between 2011 and 2021. Despite challenges in lymph node areas, the best model achieved an average Dice score of 0.816 for PTV segmentation. Our findings are a preliminary but significant step towards developing a segmentation model that has the potential to save radiation oncologists a considerable amount of time. This could allow for the treatment of more patients, resulting in improved clinical practice efficiency and more reproducible contours

    Ensemble Methods for Multi-Organ Segmentation in CT Series

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    In the medical images field, semantic segmentation is one of the most important, yet difficult and time-consuming tasks to be performed by physicians. Thanks to the recent advancement in the Deep Learning models regarding Computer Vision, the promise to automate this kind of task is getting more and more realistic. However, many problems are still to be solved, like the scarce availability of data and the difficulty to extend the efficiency of highly specialised models to general scenarios. Organs at risk segmentation for radiotherapy treatment planning falls in this category, as the limited data available negatively affects the possibility to develop general-purpose models; in this work, we focus on the possibility to solve this problem by presenting three types of ensembles of single-organ models able to produce multi-organ masks exploiting the different specialisations of their components. The results obtained are promising and prove that this is a possible solution to finding efficient multi-organ segmentation methods

    Endophytic Effects of <i>Beauveria bassiana</i> on Corn (Zea mays) and Its Herbivore, <i>Rachiplusia nu</i> (Lepidoptera: Noctuidae)

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    Entomopathogenic fungi are widely recognized as agents of biological control worldwide. Their use in agriculture for the regulation of pest populations is a promising alternative to conventional insecticides. Furthermore, recent studies have shown that entomopathogenic fungi fulfill an additional role in plants as growth promoters. The purpose of this investigation was to assess the growth and yield of corn plants colonized with Beauveria bassiana and its effect on the lepidopteran pest Rachiplusia nu. Effects of the fungus on plant growth, crop yield, and vertical transmission were evaluated in the field. Feeding preferences of R. nu larvae were assessed in the laboratory using a “choice test”. Corn plants inoculated with B. bassiana showed an increase in height, number of leaves, grain weight, yield, and percentage of seed germination compared to control plants. Consumption of B. bassiana-colonized corn plants by R. nu larvae was reduced compared to feeding levels observed on non-inoculated plants. This study showed that endophytic B. bassiana can provide multiple benefits to Zea mays and can play an important role in future integrated pest management programs.Facultad de Ciencias Naturales y MuseoInstituto de Botánica "Dr. Carlos Spegazzini

    Endophytic Effects of <i>Beauveria bassiana</i> on Corn (Zea mays) and Its Herbivore, <i>Rachiplusia nu</i> (Lepidoptera: Noctuidae)

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    Entomopathogenic fungi are widely recognized as agents of biological control worldwide. Their use in agriculture for the regulation of pest populations is a promising alternative to conventional insecticides. Furthermore, recent studies have shown that entomopathogenic fungi fulfill an additional role in plants as growth promoters. The purpose of this investigation was to assess the growth and yield of corn plants colonized with Beauveria bassiana and its effect on the lepidopteran pest Rachiplusia nu. Effects of the fungus on plant growth, crop yield, and vertical transmission were evaluated in the field. Feeding preferences of R. nu larvae were assessed in the laboratory using a “choice test”. Corn plants inoculated with B. bassiana showed an increase in height, number of leaves, grain weight, yield, and percentage of seed germination compared to control plants. Consumption of B. bassiana-colonized corn plants by R. nu larvae was reduced compared to feeding levels observed on non-inoculated plants. This study showed that endophytic B. bassiana can provide multiple benefits to Zea mays and can play an important role in future integrated pest management programs.Facultad de Ciencias Naturales y MuseoInstituto de Botánica "Dr. Carlos Spegazzini

    Stereotactic body radiation therapy for liver tumours using flattening filter free beam: dosimetric and technical considerations

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    Purpose: To report the initial institute experience in terms of dosimetric and technical aspects in stereotactic body radiation therapy (SBRT) delivered using flattening filter free (FFF) beam in patients with liver lesions.Methods and Materials: From October 2010 to September 2011, 55 consecutive patients with 73 primary or metastatic hepatic lesions were treated with SBRT on TrueBeam using FFF beam and RapidArc technique. Clinical target volume (CTV) was defined on multi-phase CT scans, PET/CT, MRI, and 4D-CT. Dose prescription was 75 Gy in 3 fractions to planning target volume (PTV). Constraints for organs at risk were: 700 cc of liver free from the 15 Gy isodose, D max < 21 Gy for stomach and duodenum, D max < 30 Gy for heart, D 0.1 cc < 18 Gy for spinal cord, V 15 Gy < 35% for kidneys. The dose was downscaled in cases of not full achievement of dose constraints. Daily cone beam CT (CBCT) was performed.Results: Forty-three patients with a single lesion, nine with two lesions and three with three lesions were treated with this protocol. Target and organs at risk objectives were met for all patients. Mean delivery time was 2.8 ± 1.0 min. Pre-treatment plan verification resulted in a Gamma Agreement Index of 98.6 ± 0.8%. Mean on-line co-registration shift of the daily CBCT to the simulation CT were: -0.08, 0.05 and -0.02 cm with standard deviations of 0.33, 0.39 and 0.55 cm in, vertical, longitudinal and lateral directions respectively.Conclusions: SBRT for liver targets delivered by means of FFF resulted to be feasible with short beam on time. © 2012 Mancosu et al; licensee BioMed Central Ltd

    Endophytic Effects of Beauveria bassiana on Corn (Zea mays) and Its Herbivore, Rachiplusia nu (Lepidoptera: Noctuidae)

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    Entomopathogenic fungi are widely recognized as agents of biological control worldwide. Their use in agriculture for the regulation of pest populations is a promising alternative to conventional insecticides. Furthermore, recent studies have shown that entomopathogenic fungi fulfill an additional role in plants as growth promoters. The purpose of this investigation was to assess the growth and yield of corn plants colonized with Beauveria bassiana and its effect on the lepidopteran pest Rachiplusia nu. Effects of the fungus on plant growth, crop yield, and vertical transmission were evaluated in the field. Feeding preferences of R. nu larvae were assessed in the laboratory using a “choice test”. Corn plants inoculated with B. bassiana showed an increase in height, number of leaves, grain weight, yield, and percentage of seed germination compared to control plants. Consumption of B. bassiana-colonized corn plants by R. nu larvae was reduced compared to feeding levels observed on non-inoculated plants. This study showed that endophytic B. bassiana can provide multiple benefits to Zea mays and can play an important role in future integrated pest management programs.Fil: Russo, Maria Leticia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Scorsetti, Ana Clara. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Vianna, María Florencia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Cabello, Marta Noemí. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; ArgentinaFil: Ferreri, Natalia Analia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Pelizza, Sebastian Alberto. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Botánica Spegazzini; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

    Initial experience of hypofractionated radiation retreatment with true beam and flattening filter free beam in selected case reports of recurrent nasopharyngeal carcinoma

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    AimTo show our preliminary experience in using TrueBeam with RapidArc technology and FFF beam for stereotactic re-irradiation of nasopharyngeal carcinoma.BackgroundThanks to new advanced techniques, as well as intensity modulated radiation therapy, it is possible to approach head and neck recurrences in selected patients. Volumetric Modulated Arc Therapy (VMAT) in its RapidArc® format, permits to reduce significantly the time to deliver complex intensity modulated plans, allowing to treat hypofractionated regimes within a few minutes. With TrueBeam it is possible to perform photon beams without usage of the flattening filter. It seems possible to expect a reduction of out-of-field dose when flattening filter free (FFF) beams are used. While research into the physics domain for FFF beams is increasing, there are very few clinical data where FFF beams are applied in clinical practice.Materials and methodsWe present here the cases of 4 patients with local or regional recurrence of nasopharyngeal carcinoma. All patients were treated using TrueBeam with RapidArc technology and FFF beam for stereotactic hypofractionated re-irradiation.ResultsAll patients concluded SBRT and showed good tolerability. During follow-up, complete response at imaging evaluation (PET and/or MRI) for all treated patients was documented.ConclusionsOur preliminary experience using TrueBeam with RapidArc technology and FFF beam for stereotactic hypofractionated re-irradiation of nasopharyngeal carcinoma was safe and effective in all 4 treated patients. Longer follow-up and a larger population of study is needed to confirm these promising results

    Pathogenic and enzyme activities of the entomopathogenic fungus <i>Tolypocladium cylindrosporum</i> (Ascomycota: Hypocreales) from Tierra del Fuego, Argentina

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    Tolypocladium cylindrosporum is an entomopathogenic fungi that has been studied as a biological control agent against insects of several orders. The fungus has been isolated from the soil as well as from insects of the orders Coleoptera, Lepidoptera, Diptera and Hymenoptera. In this study, we analyzed the ability of a strain of T. cylindrosporum, isolated from soil samples taken in Tierra del Fuego, Argentina, to produce hydrolytic enzymes, and to study the relationship of those activities to the fungus pathogenicity against pest aphids. We have made the traditional and molecular characterization of this strain of T. cylindrosporum. The expression of hydrolase activity in the fungal strain was estimated at three incubation temperatures (4ºC, 12ºC and 24ºC), on different agar media supplemented with the following specific substrates: chitin azure, Tween ® 20, casein, and urea for chitinase, lipase, protease, and urease activity, respectively. The hydrolytic-enzyme activity was estimated qualitatively according to the presence of a halo of clarification through hydrolase action, besides was expressed semi-quantitatively as the ratio between the hydrolytic-halo and colony diameters. The pathogenicity of the fungus was tested on adults of the aphid Rhopalosiphum padi at three temperatures of incubation (4ºC, 12ºC and 24ºC). The suspension was adjusted to a concentration of 1x10 7 conidia/ml. In pathogenicity assays at seven days post-inoculation, the fungus caused the mortality of adults of Ropalosiphum padi at different temperatures also showed a broad ability to grow on several agar-culture media, supplemented with different carbon sources at the three incubation temperatures tested. Although, the growth was greater with higher incubation temperatures (with maximum levels at 24°C), the fungus reached similar colony diameters after 15 days of incubation on the medium supplemented with Tween® 20 at the lower two incubation temperatures of 4°C or 12°C. In accordance with the results on colony diameters, the fungus revealed an ability to degrade casein, chitin derivatives, Tween® 20, and urea as evidenced by the appearance of a halo around the fungal colony. Because of its origin and temperature tolerance, this Argentine strain has great potential for use as a biocontrol agent for insect pest control in cold and temperate environments.Facultad de Ciencias Agrarias y Forestale

    Effects of endophytic Beauveria bassiana (Ascomycota: Hypocreales) on biological, reproductive parameters and food preference of the soybean pest Helicoverpa gelotopoeon

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    Objectives: We studied Beauveria bassiana ability to endophytic colonize soybean and its effects on some biological and reproductive parameters and on the food preference of Helicoverpa gelotopoeon, a polyphagous plague of several agronomic crops. Methods: A suspension of 1 × 108 conidia ml−1 of B. bassiana (LPSC 1098), was inoculated in soybean plants using the leaf spraying method. H. gelotopoeon survival, developement, fecundity and fertility were registered to evaluate fungal effect. Also, food preference was determined by the free-choice method. Results: B. bassiana as an endophyte adversely affected the duration of the larval stages (L1, L2, L3, L4) and of the adult stages, as well as the total duration of the life cycle. Furthermore, the oviposition period, fecundity and fertility of H. gelotopoeon decreased. This is the first report of decreased consumption of soybean leaves by H. gelotopoeon due to endophytic B. bassiana. Conclusions: This investigation shows that endophytic fungi could be considered as useful microorganisms for the integrated pest management.Consejo Nacional de Investigaciones Científicas y TécnicasInstituto de Botánica "Dr. Carlos Spegazzini"Comisión de Investigaciones Científicas de la provincia de Buenos AiresCentro de Estudios Parasitológicos y de Vectore
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