Nitrogen and potassium synergism influences the yield and quality of Dioscorea cayennensis.

This study aimed to evaluate yield, quality, nematode incidence, chlorophyll content, and primary foliar macronutrients of yam in response to nitrogen and potassium fertilization. A complete randomized block design was used in a factorial scheme (5 x 5), with five nitrogen (0; 60; 120; 180 and 240 kg ha-1 of N) and five potassium doses (0; 60; 120; 180 and 240 kg ha-1 of K2O), with four replicates. The mass, total and commercial productivity of tubers, starch content, ash, leaf N, P, and K content, chlorophyll, and nematode incidence were evaluated. The average mass of tubers obtained was 1.935 kg with doses of 133 kg ha-1 of N and 105 kg ha-1 of K2O. The dose of 178 kg ha-1 of N promoted maximum total tuber productivity (22.56 t ha-1). The doses of 132 kg ha-1 of N and 118 kg ha-1 of K2O resulted in maximum productivity of commercial tubers with 20.35 t ha-1. Leaf N and K, starch, and ash contents were within the standards for yam. The incidence of Meloidogyne, Scutellonema, and Pratylenchus reduced with the increasing simple effect doses of N and K2O. The maximum chlorophyll content was obtained at the dose of 240 kg ha-1 of N. The nitrogen and potassium interaction, despite the antagonistic effects on the accumulation of foliar P and starch, increased the productivity and average mass of commercial tubers, consequently ensuring the profitability of yam cultivation.

A high-performance method of deep learning for prostate MR-only radiotherapy planning using an optimized Pix2Pix architecture.

PURPOSE: The first aim was to generate and compare synthetic-CT (sCT) images using a conditional generative adversarial network (cGAN) method (Pix2Pix) for MRI-only prostate radiotherapy planning by testing several generators, loss functions, and hyper-parameters. The second aim was to compare the optimized Pix2Pix model with five other architectures (bulk-density, atlas-based, patch-based, U-Net, and GAN). METHODS: For 39 patients treated by VMAT for prostate cancer, T2-weighted MRI images were acquired in addition to CT images for treatment planning. sCT images were generated using the Pix2Pix model. The generator, loss function, and hyper-parameters were tuned to improve sCT image generation (in terms of imaging endpoints). The final evaluation was performed by 3-fold cross-validation. This method was compared to five other methods using the following imaging endpoints: the mean absolute error (MAE) and mean error (ME) between sCT and reference CT images (rCT) of the whole pelvis, bones, prostate, bladder, and rectum. For dose planning analysis, the dose-volume histogram metric differences and 3D gamma analysis (local, 1 %/1 mm) were calculated using the sCT and reference CT images. RESULTS: Compared with the other architectures, Pix2Pix with Perceptual loss function and generator ResNet 9 blocks showed the lowest MAE (29.5, 107.7, 16.0, 13.4, and 49.1 HU for the whole pelvis, bones, prostate, bladder, and rectum, respectively) and the highest gamma passing rates (99.4 %, using the 1 %/1mm and 10 % dose threshold criterion). Concerning the DVH points, the mean errors were -0.2% for the planning target volume V95%, 0.1 % for the rectum V70Gy, and -0.1 % for the bladder V50Gy. CONCLUSION: The sCT images generated from MRI data with the Pix2Pix architecture had the lowest image errors and similar dose uncertainties (in term of gamma pass-rate and dose-volume histogram metric differences) than other deep learning methods.

Head-and-Neck MRI-only radiotherapy treatment planning: From acquisition in treatment position to pseudo-CT generation.

PURPOSE: In context of head-and-neck radiotherapy, this study aims to compare MR image quality according to diagnostic (DIAG) and radiotherapy (RT) setups; and to optimise an MRI-protocol (including 3D T1 and T2-weighted sequences) for dose-planning (based on pseudo-CT generation). MATERIALS AND METHODS: To compare DIAG and RT setups, signal-to-noise-ratio (SNR) and percentage-image-uniformity (PIU) were computed on T1 images of phantoms and volunteers. Influence of the sample conductivity on SNR was quantified using homemade phantoms. To obtain reliable T1 and T2 images for RT-planning, an experimental design was performed on volunteers by using SNR, contrast-to-noise-ratio (CNR) and mean-opinion-score (MOS). Further, pseudo-CTs were generated from 8 patients T2 images with a state-of-art deep-learning method. These pseudo-CTs were evaluated by mean-absolute-error (MAE) and mean-error (ME). RESULTS: SNR was higher for DIAG-setup compared to RT-setup (SNR-ratio=1.3). A clear influence of the conductivity on SNR was observed. PIU was higher for DIAG-setup (38.8%) compared to RT-setup (33.5%). Regarding the protocol optimisation, SNR, CNR, and MOS were 20.6, 6.16, and 3.91 for the optimal T1 sequence. For the optimal T2 sequence, SNR, CNR and MOS were 25.6, 44.46 and 4.0. In the whole head-and-neck area, the mean MAE and ME of the pseudo-CTs were 82.8 and -3.9 HU. CONCLUSION: We quantified the image quality decrease induces by using an RT-setup for head-and-neck radiotherapy. To compensate this decrease, an MRI protocol was optimised by using an experimental design. This protocol of 15minutes provides accurate images which could be used for MRI-dose-planning in clinical practice.

[MRI-based radiotherapy planning]. / Planification à partir d'imagerie par résonance magnétique en radiothérapie.

MRI-based radiotherapy planning is a topical subject due to the introduction of a new generation of treatment machines combining a linear accelerator and a MRI. One of the issues for introducing MRI in this task is the lack of information to provide tissue density information required for dose calculation. To cope with this issue, two strategies may be distinguished from the literature. Either a synthetic CT scan is generated from the MRI to plan the dose, or a dose is generated from the MRI based on physical underpinnings. Within the first group, three approaches appear: bulk density mapping assign a homogeneous density to different volumes of interest manually defined on a patient MRI; machine learning-based approaches model local relationship between CT and MRI image intensities from multiple data, then applying the model to a new MRI; atlas-based approaches use a co-registered training data set (CT-MRI) which are registered to a new MRI to create a pseudo CT from spatial correspondences in a final fusion step. Within the second group, physics-based approaches aim at computing the dose directly from the hydrogen contained within the tissues, quantified by MRI. Excepting the physics approach, all these methods generate a synthetic CT called "pseudo CT", on which radiotherapy planning will be finally realized. This literature review shows that atlas- and machine learning-based approaches appear more accurate dosimetrically. Bulk density approaches are not appropriate for bone localization. The fastest methods are machine learning and the slowest are atlas-based approaches. The less automatized are bulk density assignation methods. The physical approaches appear very promising methods. Finally, the validation of these methods is crucial for a clinical practice, in particular in the perspective of adaptive radiotherapy delivered by a linear accelerator combined with an MRI scanner.

SISSY: An efficient and automatic algorithm for the analysis of EEG sources based on structured sparsity.

Over the past decades, a multitude of different brain source imaging algorithms have been developed to identify the neural generators underlying the surface electroencephalography measurements. While most of these techniques focus on determining the source positions, only a small number of recently developed algorithms provides an indication of the spatial extent of the distributed sources. In a recent comparison of brain source imaging approaches, the VB-SCCD algorithm has been shown to be one of the most promising algorithms among these methods. However, this technique suffers from several problems: it leads to amplitude-biased source estimates, it has difficulties in separating close sources, and it has a high computational complexity due to its implementation using second order cone programming. To overcome these problems, we propose to include an additional regularization term that imposes sparsity in the original source domain and to solve the resulting optimization problem using the alternating direction method of multipliers. Furthermore, we show that the algorithm yields more robust solutions by taking into account the temporal structure of the data. We also propose a new method to automatically threshold the estimated source distribution, which permits to delineate the active brain regions. The new algorithm, called Source Imaging based on Structured Sparsity (SISSY), is analyzed by means of realistic computer simulations and is validated on the clinical data of four patients.

A single high dose of dexamethasone affects the phosphorylation state of glutamate AMPA receptors in the human limbic system.

Glucocorticoids (GC) released during stress response exert feedforward effects in the whole brain, but particularly in the limbic circuits that modulates cognition, emotion and behavior. GC are the most commonly prescribed anti-inflammatory and immunosuppressant medication worldwide and pharmacological GC treatment has been paralleled by the high incidence of acute and chronic neuropsychiatric side effects, which reinforces the brain sensitivity for GC. Synapses can be bi-directionally modifiable via potentiation (long-term potentiation, LTP) or depotentiation (long-term depression, LTD) of synaptic transmission efficacy, and the phosphorylation state of Ser831 and Ser845 sites, in the GluA1 subunit of the glutamate AMPA receptors, are a critical event for these synaptic neuroplasticity events. Through a quasi-randomized controlled study, we show that a single high dexamethasone dose significantly reduces in a dose-dependent manner the levels of GluA1-Ser831 phosphorylation in the amygdala resected during surgery for temporal lobe epilepsy. This is the first report demonstrating GC effects on key markers of synaptic neuroplasticity in the human limbic system. The results contribute to understanding how GC affects the human brain under physiologic and pharmacologic conditions.

The most fulminant course of the Marburg variant of multiple sclerosis-autopsy findings.

Multiple sclerosis (MS) is usually a chronic and disabling inflammatory disease. Marburg's type of MS is characterized by rapid progression and severe disease course that leads to death within one year after the onset of clinical signs. We describe a fulminant clinical presentation of this malignant subtype of MS and discuss the neuropathological hallmarks as well as differential diagnoses of other fulminant demyelinating diseases. To the best of our knowledge, this is the most fulminant course of this MS variant reported in the literature.

Effective stabilization of CLA by microencapsulation in pea protein.

CLA was microencapsulated by spray drying in ten varied wall systems (WS) consisting of pea protein isolate or pea protein concentrate (PPC) alone at varied core:WS ratios (1:2; 1:3 and 1:4), or blended with maltodextrin (M) and carboxymethylcellulose at a pea protein:carbohydrate ratio of 3:1. The physical-chemical properties of the CLA microparticles were characterised by core retention, microencapsulation efficiency (ME), particle size and moisture. CLA:M:PPC (1:1:3) showed the most promising results, thus we evaluated the effect of M addition in the WS on other physical-chemical characteristics and oxidative stability (CLA isomer profile, quantification of CLA and volatile compounds by SPME coupled with CG-MS) during two months of storage at room temperature, CLA:PPC (1:4) was selected for comparisons. CLA:M:PPC (1:1:3) microparticles demonstrated better morphology, solubility, dispersibility and higher glass-transition temperature values. M addition did not influence the oxidative stability of CLA, however its presence improved physical-chemical characteristics necessary for food applications.

Opsoclonus-myoclonus syndrome associated with Mycoplasma pneumoniae infection in an elderly patient.

Opsoclonus-myoclonus-ataxia syndrome (OMS) is a rare movement disorder characterized by chaotic saccadic, high amplitude, multidirectional and involuntary eye movements usually associated with myoclonus affecting the head, trunk, limbs and signs of cerebellar ataxia, especially the inability to stand and walk. We report a case of a 68 years-old woman, with previous history of diabetes mellitus and systemic hypertension that was referred for evaluation due to headache and low fever for three days. One day after the admission, she developed spatial and temporal disorientation and high-fever (39 °C). On her fourth day in-hospital, while still disoriented, diffuse limb myoclonia and intermittent, multidirectional and chaotic eye movements were noticed. Sorological tests and sputum Mycoplasma real-time PCR were positive on seventh day in-hospital. Patient was treated with Azithromycin and IV Immunoglobulin for five days. On third day after treatment it was noticed significant improvement of ataxia and myoclonia. Completely recovery after macrolydes and IVIg treatment, absence of a malignant neoplasia and knowledge of this entity in pediatric population support that parainfectious OMS associated with M. pneumoniae infections should be considered in the differential diagnosis of OMS in adults.

[Hilbert transform-based modelling of EKG].

Recent developments in modeling methods on the non-linear and non-stationary data, such as electrocardiograms (ECG), have received large attention by the time-frequency analysts. The technique presented in this paper is based on parametrical modeling of the instantaneous module as well as instantaneous phase, estimated directly from each ECG beat. The estimation is adaptive since, the parameters related to a specific ECG beat are calculated from a given reference signal. In order to evaluate the performance of our technique, data recorded from the MIT-BIH arrhythmia database are used.

Evaluation of two personal dosemeters in polyenergetic mono- and multi-directional neutron fields.

The neutron dose-equivalent response of two commercially available electronic personal neutron dosemeters was studied in several laboratory-produced broad-spectrum neutron fields. Fluence-weighted mean energies ranged from 200 keV to 4 MeV; personal dose-equivalent rates ranged from 75 to 10 mSv h(-1); and angles of incidence were multidirectional, 0 degrees, 30 degrees and 60 degrees. Three of these fields have been shown previously to resemble ones found in CANDU (Canadian Deuterium Uranium is a registered trademark of the Atomic Energy of Canada Limited) power plant workplaces. Both dosemeters were found to perform reasonably well across the range of energy spectra and angles of incidence. One type of dosemeter displayed values of the personal dose equivalent that were, at worst, within a factor of approximately 2 of the reference values and, at best, within a few per cent of the reference values. The other type displayed values of the personal dose equivalent that were consistently within unity and 20% of the reference values. Although the radiological performance of one was found to be more accurate, this device was also found to be the less rugged of the two. Some of the data acquired in this work were compared with results previously published by others. There was consistency between these sets of data.

Usefulness of laboratory neutron fields.

A moderator-type neutron survey meter, intended for radiation protection use at a nuclear power plant, was tested in five laboratory neutron fields, including neutron fields that resemble ones found in some reactor workplaces. Calibration constants (counts Sv(-1)) and responses (ratios of measured to reference values of ambient dose equivalent) were determined by measurement for each neutron field. Theoretical calibration constants were calculated for each field using a response function from the literature. These theoretical calibration constants were consistent with ones determined from measurement. Theoretical calibration constants were also calculated for several power-plant workplace neutron spectra. The range of calibration constants determined provided some insight into the amount of over-response and under-response that this particular survey meter would be likely to give when used in the intended workplace. Values for the calibration constant were suggested.

Characterisation of laboratory-produced CANDU-like workplace neutron fields.

Two neutron fields were produced in the Neutron Irradiation Facility (NIF) at the Chalk River Laboratories of the Atomic Energy of Canada Ltd. by directing (d,D) neutrons from a 150 kV neutron generator through a specially designed moderator assembly. Bonner sphere and proton recoil spectrometry systems were used to characterise these fields to determine whether they were CANDU-like*, i.e. whether they resembled neutron fields found in workplaces around pressurised heavy-water moderated power reactors such as CANDU reactors. Similarities were found between the distributions in energy of neutron fluence and ambient dose equivalent of the neutron fields produced in the NIF and those measured previously in power plants. In addition, there was agreement between theoretical (Monte Carlo) data and measured data, thereby validating continued use of Monte Carlo modelling for field characterisations in the NIF. The CANDU-like fields add to the repertoire of neutron fields available in the NIF and are expected to be useful for evaluating neutron dosemeters.

Cytochrome P4501A1 polymorphisms in South American Indians.

A total of 131 individuals from five Brazilian Indian tribes were studied for two CYP1A1 gene polymorphisms. The presence of the *val allele at codon 462 varied from 54% in the Surui to 97% in the Xavante, while the presence of the MspI restriction site (*m2 allele) at position T6235C ranged from 72% in the Gavião to 95% in the Xavante. The haplotypes derived from these two sites showed a highly heterogeneous distribution among the five populations. The most common haplotype in South Amerindians was *val/*m2 (54% to 94%). This prevalence is the highest that has been observed in any world population.

Calibration of a portable tritium-in-air monitor for various radioactive gases.

A commercially available portable tritium-in-air monitor was calibrated for detecting the concentration of tritium-in-air, 14C-in-air, and various radioactive noble gases. Calibrations were performed both experimentally, using assayed quantities of the calibration gases, and theoretically, by simulating the monitor's response using Monte Carlo code. The experimental and theoretical calibrations agreed within +/- 10% for all gases tested with the exception of 41Ar-in-air where the agreement was approximately 20%. The results show that, although the monitor can be used to measure a wide range of radioactive gases, if more than one gas is present the monitor can not be used to accurately determine the concentration of, and hazard posed by, these gases. It is also shown that the monitor's ability to accurately assess tritium-in-air hazards would be seriously compromised by the presence of other radioactive gases.

Neutron fields inside containment of a CANDU600-PHWR power plant.

Neutron fields in six locations inside containment of a CANDU600-PHWR power plant were characterized using Bonner-sphere spectrometry. Unfolded fluence spectra were used to predict and understand the behavior of a rem meter (a moderator-type dose equivalent survey instrument). The suitability of employing commonly-used sources such as 241Am-Be for calibrating the rem meter was investigated by calculational means. Results of these calculations suggest that employing a calibration field more representative of the power-plant fields would likely provide more accurate dose equivalents.

Edpidemia de fiebre aftosa en Bage, Rs, Brasil, 1980. Evaluacion de dos sistemas de vacunacion / Epidemic of foot-and-mouth disease in Bage, Rs, Brazil, 1980. Evaluation of two systems of vaccination

El programa de control de la fiebre aftosa en Rio Grande do Sul, Brasil, se inicio en 1965. Desde 1979 gran parte del municipio de Bage, en este estado, cuenta con un programa demonstrativo de vacunacion con vacuna antiaftosa inactivada y con adyuvante oleoso producida por el Centro Panamericano de Fiebre AFtosa (CPFA). Durante 1980 el citado municipio fue afectado por una epidemia de febre aftosa producida por el virus O1. El presente trabajo analiza las consecuencias morbidas de la enfermedad en el rebaño sometido a este programa de vacunacion con relacion al resto del rebano bovino del municipio que es vacunado con vacuna de hidroxido de aluminio-saponina, inactivada en velhiculo acuoso (denominado sistema "comercial"). La enfermedad se registro en 73 rebaños de los 1.813 sometidos al sistema "comercial" y en 20 de los 620 pertenecientes al programa de vacuna oleosa, lo que dio tasas de rebaños afectados, con ajuste al tamano, de 5 y 2% respectivamente. Las tasas de morbilidad pra la poblacion bovina del municipio fueron de 45 y 6 por mil, respectivamente, para ambos sistemas de vacunacion. Separando las poblaciones que habian recibido solamente una vacunacion con vacuna oleosa al principio de la epidemia de aquellas que recibieron 2 o mas, las diferencias de morbi-mortalidad entre los grupos fueron mas acentuadas, siendo las tasas de morbilidad y mortalidad por mil bovinos respectivamente de 323 y 9,7 para los sometidos a solamente una vacunacion con vacuna oleosa, y de 29 y 0,08 para los que recibieron dos o mas vacunaciones con vacuna oleosa. Se concluye que la vacunacion con adyuvante oleoso aplicada en forma oficial dio resultados altamente satisfactorios teniendo en cuenta la alta exposicion viral a la que estuvo sometida la poblacion del municipio.