Early therapeutic drug monitoring of methotrexate and its association with acute kidney injury: A retrospective cohort study.

INTRODUCTION: High-dose methotrexate (HDMTX) use can be limited by the development of acute kidney injury (AKI). Early AKI detection is paramount to prevent further renal injury and irreversible toxicities. This study sought to determine whether early elimination patterns of MTX would be useful as a biomarker of AKI in HDMTX treatment. METHODS: This retrospective cohort study included two sites that collected ≥2 MTX levels within 16 h from completion of MTX infusion. Early levels were tagged and MTX elimination half-life (t½) were calculated from combinations of two of three different early time periods. Receiver operating characteristic (ROC) curves were synthesized for each elimination t½ (biomarker) with respect to AKI and delayed methotrexate elimination (DME); the biomarker with the highest area under the ROC curve (AUC) was tested in a multiple variable logistic regression model. RESULTS: Data from 169 patients who received a total of 556 courses of HDMTX were analyzed. ROC analysis revealed MTX elimination t½ calculated from the second and third time periods had the highest AUC for AKI at 0.62 (interquartile range [IQR] 0.56-0.69) and DME at 0.86 (IQR 0.73-1.00). After adjusting for age, sex, dose (mg/m2), infusion duration, HDMTX course, and baseline estimated glomerular filtration rate, it remained significant for AKI with an OR of 1.29 and 95% confidence interval of 1.03-1.65. CONCLUSION: Early MTX elimination t½ measured within 16 h of infusion completion was significantly associated with the development of AKI and serves as an early clearance biomarker that may identify patients who benefit from increased hydration, augmented leucovorin rescue, and glucarpidase administration.

Influence of light-emitting diodes (LEDs) on the 2,4-diclorophenoxyacetic acid phytoremediation by plectranthus neochilus.

2,4-Dichlorophenoxyacetic acid (2,4-D) is an herbicide widely used in crops against broadleaf weeds. However, 2,4-D residues are considered an environmental pollutant in bodies of water. Phytoremediation with Plectranthus neochilus is a substantial strategy to remove 2,4-D from the aquatic environment. The objective of this study was to verify the efficiency of the association of the photostimulus by Light Emitting Diodes (LED) with P. neochilus to improve phytoremediation of 2,4-D in water. Phytoremediation was evaluated with the following samples: natural light, white LED, blue LED, and red LED, with and without the plant as controls. The data corresponding to the validation of the method were in accordance with the required parameters: R2: 0.9926; RSD: 1.74%; LOD: 0.075 mg.L-1; LOQ: 0.227 mg.L-1 and recovery by SPE was 76.57%. The efficiency of the association of LED with P. neochilus in the 28 days was: ambient light + plant (47.0%); white light + plant (37.10%); blue light + plant (26.80%); red light + plant (3.32%). This study demonstrated, for the first time, the efficiency of using LEDs light in association with P. neochilus for the phytoremediation of 2,4-D in water.

Phytoremediation of organic compounds in water is a time-consuming process and generally unfavorable to the plant. This study demonstrated that the photostimulation with blue and red LED lights can accelerate the phytoremediation of the herbicide by P. neochilus, decreasing the t_1/2 of 2,4-D in water by 2 and 5 times, respectively. We equate the time of this process to physical-chemical degradation methods, but without the use of reagents, creating a green strategy to accelerate the decontamination of water resources contaminated with pesticides.

Degradation of atrazine, glyphosate, and 2,4-D in soils collected from two contrasting crop rotations in Southwest Chaco, Argentina.

Argentina stands as one of the leading consumers of herbicides. In a laboratory incubation experiment, the persistence and production of degradation metabolites of Atrazine, 2,4-D, and Glyphosate were investigated in a loamy clay soil under two contrasting agricultural practices: continuous soybean cultivation (T1) and intensified rotations with grasses and legumes (T2). The soils were collected from a long-term no-till trial replicating the influence of the meteorological conditions in the productive region. The soil was enriched with diluted concentrations of 6.71, 9.95, and 24 mg a.i./kg-1 of soil for the respective herbicides, equivalent to annual doses commonly used in the productive region. Samples were taken at intervals of 0, 0.5, 1, 2, 4, 6, 8, 16, 32, and 64 days, and analysis was conducted using high-resolution liquid chromatography UPLC MS/MS. An optimal fit to the first-order kinetic model was observed for each herbicide in both rotations, resulting in relatively short half-lives. Intensified crop sequences favored the production of biotic degradation metabolites. The impact of the high frequency of soybean cultivation revealed a trend of soil acidification and a reduced biological contribution to attenuation processes in soil contamination.

High variability in Factor IX one-stage assay in samples spiked with nonacog beta pegol among different pairs of reagent/detection system.

INTRODUCTION: Haemophilia B (HB) is an X-linked hereditary bleeding disorder characterized by coagulation factor IX (FIX) deficiency. To improve the quality of life of patients and adherence to treatment, recombinant factor concentrates modified to extend their half-life have been developed, called extended half-life factors (EHL: extended half-life). Nonacog beta pegol (N9-GP) is a glycopegylated recombinant human FIX molecule that has a half-life of 93 h with a single dose and has shown a higher recovery percentage than other molecules. To diagnose and monitor the treatment of haemophiliac patients, FIX activity is determined with the one-stage clotting assay (OSA) and/or the chromogenic assay. The objective of this work, carried out in three centres, was to measure the recovery of N9-PG with 10 different activated partial thromboplastin time (APTT) reagents on three platforms, in samples spiked in vitro with N9-GP, at four different concentration levels. METHODS: It was measured the recovery of N9-GP with 10 different APTT reagents (polyphenol, ellagic acid, silice dioxide, colloidal silica as APTT activator on three platforms, in sample spiked in vitro with N9-GP. RESULTS: The results show heterogeneity in the activity of N9-GP measured by OSA with the different APTT reagents when the calibrations were performed with the specific calibrator of each coagulometer. A recovery percentage between 87% and 108% was obtained only with polyphenol and ellagic acid as activator in the three platforms evaluated. The other reagents studied overestimate or underestimate, with no clear profile. When a calibration curve was performed with a calibrator prepared from the N9-GP vial, all APTT reagents met the established recovery requirement. CONCLUSION: APTT reagents with polyphenol or ellagic acid as activator would be the only ones appropriate when using the commercially available OSA with specific calibrator to monitor patients treated with N9-GP.

Alta variabilidad en la determinación del Factor IX en muestras de plasma adicionadas con nonacog beta pegol entre distintos pares de reactivos/sistemas de detección / High variability in the determination of Factor IX in plasma samples spiked with nonacog beta pegol between different reagents/detection system pairs / Alta variabilidade na determinação do Fator IX em amostras de plasma enriquecidas com nonacog beta pegol entre diferentes pares de reagentes/ sistema de detecção

Resumen La hemofilia B es un trastorno hemorrágico hereditario, ligado al cromosoma X, que se caracteriza por el déficit del factor IX (FIX) de la coagulación. Para mejorar la calidad de vida de los pacientes y la adherencia al tratamiento se han desarrollado concentrados de factores recombinantes modificados para extender su vida media, denominados factores de vida media extendida (EHL: extended half life concentrates). El nonacog beta pegol (N9-GP) es una molécula de FIX humano recombinante glicopegilada que tiene una vida media de 93 h con una sola dosis y ha mostrado un porcentaje de recuperación mayor que otras moléculas. Para diagnosticar y monitorear el tratamiento del paciente hemofílico se determina la actividad del FIX con el ensayo coagulable en una etapa (OSA: one stage assay) y/o en el ensayo cromogénico. El objetivo de este trabajo, realizado en tres centros, fue medir la recuperación de N9-GP con 10 reactivos de APTT diferentes en tres plataformas, en muestras deficientes en FIX adicionadas in vitro con N9-GP, en cuatro niveles de concentración diferentes. Los resultados muestran una heterogeneidad en la actividad de N9-GP medidos por OSA con los diferentes reactivos de APTT cuando se realizaron las calibraciones con el estándar específico de cada coagulómetro. Se obtuvo un porcentaje de recuperación mayor de 92% con Cephascreen, Actin FSL y APTTest elágico en las tres plataformas evaluadas. Estos reactivos serían los únicos apropiados cuando se usa el OSA calibrado con plasma comercial para monitorear el tratamiento de los pacientes que reciben N9-GP.

Abstract Hemophilia B (HB) is an X-linked hereditary bleeding disorder characterised by coagulation factor IX (FIX) deficiency. To improve the quality of life of patients and adherence to treatment, recombinant factor concentrates glicomodified to extend their half-life have been developed. These are called extended half-life factors (EHL: extended half-life concentrates). Nonacog beta pegol (N9-GP) is a glycopegylated recombinant human FIX molecule that has a half-life of 93 h with a single dose and has shown a higher recovery percentage than other molecules. For diagnosis and monitoring the treatment of hemophiliac patients, FIX activity is determined with the One Stage Clotting Assay (OSA) and/or the chromogenic assay. The objective of this work, carried out in three centres, was to measure the recovery of N9-GP with 10 different APTT reagents on three platforms, in FIX deficient samples spiked in vitro with N9-GP, at four different concentration levels. The results show a heterogeneity in the activity of N9-GP measured by OSA with the different APTT reagents when the calibrations were performed with the specific standard of each coagulometer. A recovery percentage greater than 92% was obtained with Cephascreen, Actin FSL and APTTest ellagic in the three platforms evaluated. These reagents would be the only ones appropriate when using the commercial plasma-calibrated OSA to monitor the treatment of patients treated with N9-GP.

Resumo A hemofilia B é uma doença hemorrágica hereditária ligada ao cromossomo X caracterizada pela deficiência do fator de coagulação IX (FIX). Para melhorar a qualidade de vida dos pacientes e a adesão ao tratamento, foram desenvolvidos concentrados de fatores recombinantes modificados para prolongar sua meia-vida, chamados de fatores de meia-vida estendida (EHL: extended half life concentrates). Nonacog beta pegol (N9-GP) é uma molécula de FIX humano recombinante glicopeguilada que tem meia-vida de 93 h com uma dose única e mostrou uma porcentagem de recuperação maior do que outras moléculas. Para diagnosticar e monitorar o tratamento de pacientes hemofílicos, a atividade do FIX é determinada com o ensaio coagulável em um estágio (OSA: One Stage Assay) e/ou o ensaio cromogênico. O objetivo deste trabalho, realizado em três centros, foi medir a recuperação de N9-GP com 10 reagentes de APTT diferentes em três plataformas, em amostras deficiente de fator IX adicionadas in vitro com N9-GP, em quatro níveis de concentração diferentes. Os resultados mostram uma heterogeneidade na atividade de N9-GP medidos por OSA com os diferentes reagentes de APTT quando as calibragens foram realizadas com o padrão específico de cada coagulômetro. Uma porcentagem de recuperação superior a 92% foi obtida com Cephascreen, Actin FSL e APTTest elágico nas três plataformas avaliadas. Esses reagentes seriam os únicos apropriados ao usar o OSA calibrado com plasma comercial para monitorar o tratamento de pacientes tratados com N9-GP.

Diuron, hexazinone, and sulfometuron-methyl applied alone and in mixture in soils: Distribution of extractable residue, bound residue, biodegradation, and mineralization.

Biodegradation studies of herbicides applied to the soil alone and in a mixture are required since herbicides are often used in combinations to control weeds. When herbicides are applied in mixtures, interactions may affect their environmental fate. Thus, the objective of this study was to evaluate the distribution of extractable residue, bound residue, biodegradation, and mineralization of diuron, hexazinone, and sulfometuron-methyl when applied alone and in a mixture in two agricultural soils. Biometric flasks filled with two types of soil (clay and sandy) collected from an area cultivated with sugarcane and treated with 14C-radiolabeled solutions of the herbicides were incubated for 70 d. More 14C-CO2 was released when sulfometuron-methyl and hexazinone were applied in a mixture compared to when applied alone. Being used in a combination did not affect the mineralization of diuron. The soil texture directly influenced the mineralization, bound residue, and extractable residue of the three herbicides. The percentage of extractable residue decreased over time for all herbicides. Hexazinone and sulfometuron-methyl had the highest residue extracted on sandy soil when applied alone. Diuron showed the highest percentage of bound residue. The degradation of the three herbicides was higher in the clay soil regardless of the mode of application, which is related to the higher potential of the bacterial community in the clay soil to mineralize the herbicides.

Immunogenicity of Current and New Therapies for Hemophilia A.

Anti-drug antibody (ADA) development is a significant complication in the treatment of several conditions. For decades, the mainstay of hemophilia A treatment was the replacement of deficient coagulation factor VIII (FVIII) to restore hemostasis, control, and prevent bleeding events. Recently, new products have emerged for hemophilia A replacement therapy, including bioengineered FVIII molecules with enhanced pharmacokinetic profiles: the extended half-life (EHL) recombinant FVIII products. However, the main complication resulting from replacement treatment in hemophilia A is the development of anti-FVIII neutralizing alloantibodies, known as inhibitors, affecting approximately 25-30% of severe hemophilia A patients. Therefore, the immunogenicity of each FVIII product and the mechanisms that could help increase the tolerance to these products have become important research topics in hemophilia A. Furthermore, patients with inhibitors continue to require effective treatment for breakthrough bleedings and procedures, despite the availability of non-replacement therapy, such as emicizumab. Herein, we discuss the currently licensed treatments available for hemophilia A and the immunogenicity of new therapies, such as EHL-rFVIII products, compared to other products available.

A Molecular Marker to Identify Spodoptera frugiperda (JE Smith) DNA in Predators' Gut Content.

Spodoptera frugiperda is a serious pest of maize and other crops worldwide. The integration of control tactics is recommended for S. frugiperda suppression because reports of insecticide and Btplant-resistance are frequent. Biological control agents would be an alternative to improve S. frugiperda control in agricultural areas. We constructed a species-specific molecular marker to detect S. frugiperda DNA in predators' gut content and estimated the predation rates of ladybugs and earwigs on S. frugiperda in maize crops. Predators were sampled in Pirassununga, São Paulo state, Brazil, in 2020 and 2021. Using the species-specific molecular marker in laboratory conditions, we estimated the half-life time to detect S. frugiperda DNA in the gut contents of Hippodamia convergens as 6.16 h and Doru luteipes as 25.72 h. The weekly predation rate of S. frugiperda by predators in maize crop varied from 0 to 42.1% by ladybugs and from 0 to 9.2% by D. luteipes. Predation events on S. frugiperda by predators were more frequent during the maize reproductive stage. Our results confirmed that predators might contribute to S. frugiperda suppression in maize fields. However, further studies of prey-predator interactions and agricultural landscapes are essential for a better understanding of predator dynamics in crops.

Dynamics of the canonical RNA degradosome components during glucose stress.

The RNA Degradosome (RNAD) is a multi-enzyme complex, which performs important functions in post-transcriptional regulation in Escherichia coli with the assistance of regulatory sRNAs and the RNA chaperone Hfq. Although the interaction of the canonical RNAD components with RNase E has been extensively studied, the dynamic nature of the interactions in vivo remains largely unknown. In this work, we explored the rearrangements upon glucose stress using fluorescence energy transfer (hetero-FRET). Results revealed differences in the proximity of the canonical components with 1% (55.5 mM) glucose concentration, with the helicase RhlB and the glycolytic enzyme Enolase exhibiting the largest changes to the C-terminus of RNase E, followed by PNPase. We quantified ptsG mRNA decay and SgrS sRNA synthesis as they mediate bacterial adaptation to glucose stress conditions. We propose that once the mRNA degradation is completed, the RhlB, Enolase and PNPase decrease their proximity to the C-terminus of RNase E. Based on the results, we present a model where the canonical components of the RNAD coalesce when the bacteria is under glucose-6-phosphate stress and associate it with RNA decay. Our results demonstrate that FRET is a helpful tool to study conformational rearrangements in enzymatic complexes in bacteria in vivo.

Circumventing the side effects of L-asparaginase.

L-asparaginase is an enzyme that catalyzes the degradation of asparagine and successfully used in the treatment of acute lymphoblastic leukemia. L-asparaginase toxicity is either related to hypersensitivity to the foreign protein or to a secondary L-glutaminase activity that causes inhibition of protein synthesis. PEGylated versions have been incorporated into the treatment protocols to reduce immunogenicity and an alternative L-asparaginase derived from Dickeya chrysanthemi is used in patients with anaphylactic reactions to the E. coli L-asparaginase. Alternative approaches commonly explore new sources of the enzyme as well as the use of protein engineering techniques to create less immunogenic, more stable variants with lower L-glutaminase activity. This article reviews the main strategies used to overcome L-asparaginase shortcomings and introduces recent tools that can be used to create therapeutic enzymes with improved features.

Ozonation of quinoa seeds (Chenopodium quinoa Willd. ): saturation and decomposition kinetics of ozone and physiological quality of seeds / Ozonização de sementes de quinoa (Chenopodium quinoa Willd. ): saturação e cinética de decomposição do ozônio e qualidade fisiológica das sementes

Ozonation has been evaluated as an alternative method for seed treatment. In this context, the goal of this study was to evaluate the saturation process and kinetics of decomposition of ozone in a porous medium composed of quinoa BRS Syetetuba and possible changes in seed quality. Ozone concentration and saturation time in the porous medium and half-life were determined by adopting an inlet ozone concentration of 885 ppm and a flow rate of 5.0 L min-1 at 25 °C. The ozonation periods adopted were 0, 30, 60, 90, and 120 min. Regarding the physiological quality of the seeds, the germination percentage, germination speed index, electrical conductivity, and length of the shoot, root, and normal seedlings were analyzed. At the inlet ozone concentration of 885 ppm and a flow rate of 5.0 L min-1, the saturation concentration and saturation time in the porous medium composed of quinoa were 522.5 ppm and 12.0 min, respectively. The half-life of ozone in the porous medium was 6.08 min at 25 °C. Under these conditions, ozonation did not affect the physiological quality of quinoa BRS Syetetuba seeds for up to 120 min.(AU)

A ozonização tem sido avaliada como método alternativo para tratamento de sementes. Nesse contexto, objetivou-se avaliar o processo de saturação e a cinética de decomposição do ozônio em meio poroso composto de quinoa, cv. BRS Syetetuba, e possíveis alterações na qualidade das sementes. Determinaramse a concentração e o tempo de saturação do ozônio no meio poroso e a meia-vida, adotando-se concentração de entrada de 885 ppm, vazão de 5,0 L min-1, a 25 ºC. Os períodos de ozonização adotados foram 0, 30, 60, 90 e 120 min. Quanto à qualidade fisiológica das sementes, analisaram-se o percentual de germinação, índice de velocidade de germinação, condutividade elétrica e comprimentos da parte aérea, do sistema radicular e das plântulas normais. Para concentração de entrada do ozônio de 885 ppm e vazão de 5,0 L min-1, a concentração e o tempo de saturação do ozônio no meio poroso composto de quinoa foi de 522,5 ppm e 12,0 min, respectivamente. A meia-vida do ozônio em meio poroso foi de 6,08 min, a 25 ºC. Nas condições a adotadas, a ozonização não afeta a qualidade fisiológica das sementes de quinoa, cv. BRS Syetetuba, por até 120 min.(AU)

Alpha-decay half-life of Hafnium isotopes reinvestigated by a semi-empirical approach.

- New estimates of partial α-decay half-life, T1/2, for 156-162,174,176Hf isotopes by a semi-empirical, one-parameter model are given. The used model is based on the quantum mechanical tunneling mechanism through a potential barrier, where the Coulomb, centrifugal and overlapping components to the barrier have been considered within the spherical nucleus approximation. This approach enables to reproduce, within a factor 2, the measured T1/2 of ground-state to ground-state (gs-gs) α-transitions for the artificially produced 156-162Hf isotopes. Half-life predictions for α-transitions from the ground-state of 159,161Hf isotopes to the first gamma-excited level of 155,157Yb isotopes are reported for the first time. The model also provides T1/2-values of (2.43±0.28)×1016 a and (1.47±0.19)×1020 a for the naturally occurring 174Hf and 176Hf isotopes, respectively, in quite good agreement with a number of estimates by other authors. In addition, the present methodology indicates that 174,176Hf isotopes exhibit α-transition to the first gamma-excited level of their daughter Ytterbium isotopes which half-lives are found (0.9±0.1)×1018 a and (0.72±0.08)×1022 a, respectively, with a chance of being measured by improved α-detection and α-spectrometry methods available nowadays.

Partial alpha-decay half-lives for alpha-emitting Osmium isotopes: Accurate determinations by a semi-empirical model.

Partial alpha-decay half-life-values for twenty-four cases of alpha-decaying Osmium isotopes (161-174, 184, 186-188Os) have been obtained in the framework of a semi-empirical, one-parameter model based on the quantum mechanical tunneling mechanism through a potential barrier. Here the Coulomb, centrifugal and overlapping contributions to the barrier have been considered within the spherical nucleus approximation. The calculation method enabled to reproduce, within a factor 2, the measured half-lives for ground-state to ground-state (gs-gs) α-transitions of twelve artificially produced Osmium isotopes (162-172, 174Os) and of two naturally occurring isotopes (184, 186Os). In addition, a half-life prediction of T½ = (2.0 ± 0.1) × 1016 a has been found for the gs-gs α-transition of naturally occurring 187Os isotope. Two cases of gamma quanta accompanying α-decay possible of being accessed experimentally have been predicted: 184Os decaying to the first level of 180W, with T½ = (0.73 ± 0.04) × 1015 a, and 186Os decaying to the first level of 182W, with T½ = (3.9 ± 0.2) × 1016 a. New α-decay schemes for 184Os, 186Os, 187Os isotopes have been anticipated, and estimated T½-values for rarer cases of α-transitions of Osmium isotopes have been reported.

Linear toxicokinetic of chlordecone in ewe's serum.

Chlordecone (CLD) is an organochlorine pesticide used in banana fields of the French West Indies between 1972 and 1993. This use resulted in a long-term pollution of soils and the possible contamination of farm animals. Indeed, after involuntary ingestion of soil, CLD is absorbed and consequently leads to contaminated animals. The aim of this study was the determination of CLD half-life and the establishment of the linearity of CLD disappearance kinetics in non-lactating adult's ewes. Chlordecone diluted in cremophor was intravenously administrated to ewes at different doses: 0.04, 0.2, or 1 mg kg-1 body weight (n = 5 for each dose). Blood samples were collected from time t = 0 to time t = 84 days. Serum samples were extracted with a solid-phase extraction and analyzed by electron capture detection gas chromatography. A two-compartmental model was applied to the serum CLD kinetics. An additional statistical analysis was applied to the observed elimination parameters in serum according to the administrated dose, and no significant differences were detected. The linear elimination of CLD between 0.04 and 1 mg kg-1 body weight allowed the possibility of ewe's extrapolation half-life in this dose range. The estimated mean CLD half-life in ewes was 24 days. Overall, the results of this study will be useful to establish decontamination strategies in small ruminants reared in contaminated CLD areas. Graphical abstract Experimental design of the CLD toxicokinetic study in ewes.

Residues Decomposition in Crop Rotations under No-till System

Abstract The effectiveness soil cover in no-till is relating to quantity and quality of the phytomass produced by crops in rotation and, its persistence over the soil depends on residues decomposition. The objective of this study was to evaluate the phytomass production, decomposition rate and the half-life of crops in rotation at the Subtropical region, Brazil. The study was carried out at the Agronomic Institute of the Paraná (IAPAR), in Ponta Grossa, Parana State, Brazil. The experimental design was randomized blocks, with six treatments and four replicates. Winter cash crops and cover crops, single and in consortium, were evaluated in the year 2014 (wheat, black oats + hairy vetch + rye, black oats + ryegrass and black oats + blue lupine), in 2015 (canola, black oats, and black oats + hairy vetch + forage turnip) and in 2016 (barley, triticale, and triticale + black oats + rye). The phytomass was evaluating by collect three subsamples of 0.25 m2 per plot. For decomposition rate and the half-life of the crop residues, litter bags (LBs) methodology was used. A mathematical model (Q=Q0exp-kt) was used to represent the crop residues decomposition and the half-life of crop residues were obtained by the equation t1/2 = (ln2)/k. Poaceae consortia, single Poaceae and canola presented higher phytomass production when compared to Poaceae-Fabaceae consortia. The half-life for Poaceae-Fabaceae corsortia was shorter than single Poaceae.

Use of Pistia stratiotes for phytoremediation of water resources contaminated by clomazone.

The Pistia stratiotes L. was tested for phytoremediation potential of the compound clomazone in water. Clomazone is a post-emergent herbicide marketed as Gamit®. Five groups with four samples each were evaluated, a low concentration control (LCC: 37.86 mg L-1), low concentration treatment (LCT: 38.16 mg L-1), high concentration control (HCC: 54.71 mg L-1), high concentration treatment (HCT: 54.33 mg L-1), and a plant control group (PCG). Plant resistance to clomazone at determined concentrations and their ability to remove the herbicide from water by HPLC over 24 days were evaluated. The results demonstrate that P. stratiotes has high resistance to clomazone exposure and was able to eliminate up to 90% of the herbicide residues during the experimental period. Under dissipation by P. stratiotes in water, clomazone had a halflife of 19.6 days for in the control treatments, LCC and HCC, and 8.0 days in the treatment groups, LCT and HCT. This study indicates that Pistia stratiotes is an effective phytoremediation agent for the herbicide clomazone in water.

Assessment of 47Ca Distribution and Biological Half-Life in Japanese Quail Chicks

A study was conducted to assess 47Calcium (47Ca) distribution and biological half-life in different body organs of Japanese quail chicks. A total of 85, 4 week old chicks, were dosed with 1ml/chick volume of 1% (w/v) CaCl2 solution containing 7.51x10-08 Ci 47Ca which is equivalent to 1.27x10-13 g. 47Ca activity, in terms of decay per minute (DPM), was measured in different body organs at 12 hours time intervals, after 24 hours from ingestion for five days. The total activity of 47Ca for each organ and activity per gram of organ (D.min-1.g-1) was calculated. Data were Statistically analyzed using completely randomized design (CRD), one way analysis of variance (ANOVA) as per the procedure given by SPSS (2002), 9.0 version for Windows. The results obtained indicated that following 47Ca administration most of the total 47Ca concentration was found in the bones with count rates of 110267±550 DPM. While in the fifth day following administration, most of the 47Ca was found in the feathers with a total activity of 13322±760 DPM. The biological half-life time was found to be highest in the heart and kidneys, respectively compared to the other body organs. In conclusion, the current results suggest that the main excretory pathway for Ca is through the skin. Regarding organ dependency on Ca for the normal functioning, the results obtained in our study suggest that the heart is the most dependent organ on Ca.

Assessment of 47Ca Distribution and Biological Half-Life in Japanese Quail Chicks

A study was conducted to assess 47Calcium (47Ca) distribution and biological half-life in different body organs of Japanese quail chicks. A total of 85, 4 week old chicks, were dosed with 1ml/chick volume of 1% (w/v) CaCl2 solution containing 7.51x10-08 Ci 47Ca which is equivalent to 1.27x10-13 g. 47Ca activity, in terms of decay per minute (DPM), was measured in different body organs at 12 hours time intervals, after 24 hours from ingestion for five days. The total activity of 47Ca for each organ and activity per gram of organ (D.min-1.g-1) was calculated. Data were Statistically analyzed using completely randomized design (CRD), one way analysis of variance (ANOVA) as per the procedure given by SPSS (2002), 9.0 version for Windows. The results obtained indicated that following 47Ca administration most of the total 47Ca concentration was found in the bones with count rates of 110267±550 DPM. While in the fifth day following administration, most of the 47Ca was found in the feathers with a total activity of 13322±760 DPM. The biological half-life time was found to be highest in the heart and kidneys, respectively compared to the other body organs. In conclusion, the current results suggest that the main excretory pathway for Ca is through the skin. Regarding organ dependency on Ca for the normal functioning, the results obtained in our study suggest that the heart is the most dependent organ on Ca.(AU)

Remaining straw and release of nutrients from oat managed in integrated crop-livestock / Palhada remanescente e liberação de nutrientes da aveia preta manejada em sistema de integração lavoura-pecuária

This study aimed to evaluate the decomposition and nutrient release from residues of the culture of oats and fallow in crop-livestock integration system. The experimental design was a randomized complete block design with two replications, as parcels being formed by four managements (fallow, oats without grazing, oats grazed once and twice), and the subplots for evaluation periods along the soybean crop in succession (0, 10, 20, 30, 50, 100 and 120 days after sowing). The residual amounts of dry matter and the contents of Carbon (C), Nitrogen (N), Phosphorus (P) and Potassium (K) were determined. Oats without grazing and fallow with natural reappearance of turnip + ryegrass were the treatments that presented the highest amount of dry matter remaining, reaching 5,219 and 6,781 kg ha-1, respectively. The amount of nutrients, N, P and K released from the residues, were similar independent from the management adopted, with exponential reduction proportional to the reduction of the remaining dry matter. K was the nutrient released faster from the residues and should be considered at the time of fertilization calculation of the culture to be implanted. The integrated crop-livestock system in which takes place one and two grazing oats, even reducing soil cover, enables high nutrient cycling.

O objetivo do trabalho foi avaliar a decomposição e liberação de nutrientes dos resíduos da cultura da aveia preta e do pousio conduzidos em sistema de integração lavoura-pecuária. O delineamento experimental utilizado foi o de blocos casualizados, em esquema de parcelas subdivididas, com duas repetições, sendo as parcelas constituídas por quatro manejos (pousio, aveia sem pastejo, aveia pastejada uma e duas vezes) e as subparcelas, pelas épocas de avaliação ao longo do cultivo da soja em sucessão (0, 10, 20, 30, 50, 100 e 120 dias após a semeadura). Foram determinadas as quantidades residuais de matéria seca e os teores de Carbono (C), Nitrogênio (N), Fósforo (P) e Potássio (K). A aveia sem pastejo e o pousio com ressemeadura natural de aveia + azevém, foram os manejos que apresentaram as maiores quantidades de matéria seca remanescentes, chegando a 5.219 e 6.781 kg ha-1, respectivamente. A quantidade dos nutrientes, N, P e K liberados dos resíduos, foram semelhantes independente do manejo adotado, com redução exponencial e proporcional à redução da matéria seca remanescente. O K foi o nutriente liberado mais rapidamente dos resíduos e deve ser considerado no momento do cálculo de adubação da cultura a ser implantada. O sistema de integração lavoura-pecuária no qual se realiza um e dois pastejos da aveia, mesmo reduzindo a cobertura do solo, possibilita elevada ciclagem de nutrientes.

Determination of the dose rate constant through Monte Carlo simulations with voxel phantoms.

PURPOSE: The main goal of this study was to determine the dose rate constant of radionuclides used in Nuclear Medicine when they are biodistributed in humans. The secondary goal was to calculate the effective half-life for the same radionuclides in order to determine the realistic dose due to the incorporation of these nuclides for a variety of reasons. METHODS: Anthropomorphic voxel phantoms, with characteristics based on ICRP-110 were considered and the biodistributions of radionuclides were simulated using the Monte Carlo code MCNPX. In addition, the effective half-lives for all simulated radionuclides were calculated. RESULTS: The results for the dose rate constant, taking into account the patient body attenuation, showed no correlation between the biodistribution of the radionuclide and the energy of the radiation emitted. Body attenuation ranged between 6.7% and 94.1%. Also, the priority angle of radiation emission was determined. The values found for the body attenuation agree with the literature, corroborating the calculation of the body dose rate constant. CONCLUSIONS: The results for the body dose rate constant calculated in this work, for 30 radionuclides and 57 radiopharmaceuticals, and their effective half-lives, may be used to estimate the dose emitted by a person who has incorporated a radionuclide in the Nuclear Medicine activity range. This dose will be optimized when the body dose rate constant and the effective half-life determined in this study are used together with dose reduction factors.