5,077 research outputs found

    Introducing the 2-DROPS model for two-dimensional simulation of crop roots and pesticide within the soil-root zone

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    Mathematical models of pesticide fate and behaviour in soils have been developed over the last 30 years. Most models simulate fate of pesticides in a 1-dimensional system successfully, supporting a range of applications where the prediction target is either bulk residues in soil or receiving compartments outside of the soil zone. Nevertheless, it has been argued that the 1-dimensional approach is limiting the application of knowledge on pesticide fate under specific pesticide placement strategies, such as seed, furrow and band applications to control pests and weeds. We report a new model (2-DROPS; 2-Dimensional ROots and Pesticide Simulation) parameterised for maize and we present simulations investigating the impact of pesticide properties (thiamethoxam, chlorpyrifos, clothianidin and tefluthrin), pesticide placement strategies (seed treatment, furrow, band and broadcast applications), and soil properties (two silty clay loam and two loam top soils with either silty clay loam, silt loam, sandy loam or unconsolidated bedrock in the lower horizons) on microscale pesticide distribution in the soil profile. 2-DROPS is to our knowledge the first model that simulates temporally- and spatially-explicit water and pesticide transport in the soil profile under the influence of explicit and stochastic development of root segments. This allows the model to describe microscale movement of pesticide in relation to root segments, and constitutes an important addition relative to existing models. The example runs demonstrate that the pesticide moves locally towards root segments due to water extraction for plant transpiration, that the water holding capacity of the top soil determines pesticide transport towards the soil surface in response to soil evaporation, and that the soil type influences the pesticide distribution zone in all directions. 2-DROPS offers more detailed information on microscale root and pesticide appearance compared to existing models and provides the possibility to investigate strategies targeting control of pests at the root/soil interface

    A Case of Cerebral Gumma Presenting as Brain Tumor in a Human Immunodeficiency Virus (HIV)-Negative Patient

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    Syphilis, along with the recent increase of human immunodeficiency virus (HIV) patients, has also been on the rise. It has a broad spectrum of clinical manifestations, among which cerebral gumma is, a kind of neurosyphilis, however, it is rare and can be cured by penicillin. Thus, cerebral gumma needs to be differentially diagnosed from other brain masses that may be present in syphilis patients. We have experienced a case where the patient was first suspected of brain tumor, but confirmed by surgery to be cerebral gumma due to neurosyphilis. This is the first such case encountered in Korea, therefore, we report it here in. A 40-year old woman complaining of headaches was found to have a brain mass on her CT scans and MRI. Suspecting a brain Tumor, a resection was performed on the patient, and histological results revealed that the central portion of the mass contained necrotic material and the peripheral region was infiltrated with plasma cells. Warthin-Starry staining of the region revealed spirochetes, and the patient was thus diagnosed as brain gumma. Venereal Disease Research Laboratory (VDRL) of cerebrospinal fluid (CSF) was reactive. After an operation, penicillin-G at a daily dose of 24×106 U was given for 10 days from post-operative day 10, and thereafter, the mass disappeared

    TDP-43 as a potential biomarker for amyotrophic lateral sclerosis:a systematic review and meta-analysis

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    Abstract Background Frontotemporal dementia (FTD) and Amyotrophic Lateral Sclerosis (ALS) are incurable, progressive and fatal neurodegenerative diseases with patients variably affected clinically by motor, behavior, and cognitive deficits. The accumulation of an RNA-binding protein, TDP-43, is the most significant pathological finding in approximately 95% of ALS cases and 50% of FTD cases, and discovery of this common pathological signature, together with an increasing understanding of the shared genetic basis of these disorders, has led to FTD and ALS being considered as part of a single disease continuum. Given the widespread aggregation and accumulation of TDP-43 in FTD-ALS spectrum disorder, TDP-43 may have potential as a biomarker in these diseases. Methods We therefore conducted a systematic review and meta-analysis to evaluate the diagnostic utility of TDP-43 detected in the cerebrospinal fluid (CSF) of patients with FTD-ALS spectrum disorder. Results From seven studies, our results demonstrate that patients with ALS have a statistically significantly higher level of TDP-43 in CSF (effect size 0.64, 95% CI: 0.1–1.19, p = 0.02). Conclusions These data suggest promise for the use of CSF TDP-43 as a biomarker for ALS

    Percutaneous Cardiopulmonary Support-Supported Percutaneous Coronary Intervention: A Single Center Experience

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    BACKGROUND AND OBJECTIVES: Percutaneous cardiopulmonary support (PCPS) has proven to be a valuable technique in high-risk coronary patients undergoing percutaneous coronary intervention (PCI). However, there have been few studies on PCI associated with PCPS in Korea. We summarized our experience with PCPS-supported PCI. SUBJECTS AND METHODS: We retrospectively reviewed 19 patients with PCPS-supported PCI between August 2005 and June 2009. PCPS was used as an elective procedure for 10 patients with at least two of the following conditions: left-ventricular ejection fraction <35%, target vessel(s) supplying more than 50% of the viable myocardium, high risk surgical patients, and patients who refused coronary bypass surgery. In the remaining 9 patients PCPS was used as an emergency procedure, to stabilize and even resuscitate patients with acute myocardial infarction and cardiogenic shock, in order to attempt urgent PCI. RESULTS: Among the 19 patients who were treated with PCPS-supported PCI, 11 (57.9%) survived and 8 (42.1%) patients did not. ST elevation myocardial infarction with cardiogenic shock was more prevalent in the non-survivors than in the survivors (75% vs. 27.3%, p=0.04). The elective PCPS-supported PCI was practiced more frequently in the survivors than in the non-survivors (72.7% vs. 25%, p=0.04). In the analysis of the event-free survival curve between elective and emergency procedures, there was a significant difference in the survival rate (p=0.025). Among the survivors there were more patients with multi-vessel disease, but a lower Thrombolysis in Myocardial Infarction grade in the culprit lesions was detected in the non-survivors, before PCI. Although we studied high-risk patients, there was no procedure-related mortality. CONCLUSION: Our experience suggests that PCPS may be helpful in high risk patients treated with PCI, especially in elective cases. More aggressive and larger scale studies of PCPS should follow

    Novel Avian Influenza H7N3 Strain Outbreak, British Columbia

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    Genome sequences of chicken (low pathogenic avian influenza [LPAI] and highly pathogenic avian influenza [HPAI]) and human isolates from a 2004 outbreak of H7N3 avian influenza in Canada showed a novel insertion in the HA0 cleavage site of the human and HPAI isolate. This insertion likely occurred by recombination between the hemagglutination and matrix genes in the LPAI virus
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