Chitosan-magnetite nanocomposite as a sensing platform to bendiocarb determination

A novel platform for carbamate-based pesticide quantification using a chitosan/magnetic iron oxide (Chit-Fe3O4) nanocomposite as a glassy carbon electrode (GCE) modifier is shown for an analytical methodology for determination of bendiocarb (BND). The BND oxidation signal using GCE/Chit-Fe3O4 compared with bare GCE was catalyzed, showing a 37.5% of current increase with the peak potential towards less positive values, showing method's increased sensitivity and selectivity. Using square-wave voltammetry (SWV), calibration curves for BND determination were obtained (n = 3), and calculated detection and quantification limits values were 2.09 × 10-6 mol L-1 (466.99 ppb) and 6.97 × 10-6 mol L-1 (1555.91 ppb), respectively. The proposed electroanalytical methodology was successfully applied for BND quantification in natural raw waters without any sample pretreatment, proving that the GCE/Chit-Fe3O4 modified electrode showed great potential for BND determination in complex samples. ᅟ Graphical abstract.The authors gratefully acknowledge the funding provided by the following Brazilian agencies: CNPq-INCT (proc. 573925/2008-9 and 573548/2008-0), CAPES/Funcap (2133/2012/proc. 23038.007973/2012-90 and PNE-0112-00048.01.00/16), CNPq (proc. 400223/2014-7, 303596/2014-7, 302801/2014-6 and 408790/2016-4), PRONEM/FUNCAP/CNPq (PNE-0112-00048.01.00/16) and PRONEX/Funcap (proc. PR2-0101-00030.01.00/15). The Fundação para a Ciência e a Tecnologia (FCT) and the FEDER, under Programme PT2020 (Project UID/QUI/50006/2013) and the project Qualidade e Segurança Alimentar- uma abordagem (nano) tecnológica (NORTE-01-0145-FEDER-000011) are also acknowledged for the financial funding. R.M.F. and J.C.D. acknowledge the financial support by Fondecyt 3170240 and Basal Program for Centers of Excellence, Grant FB0807 CEDENNA, CONICYT. C.P.S. thanks CAPES-PNPD for her grant.info:eu-repo/semantics/publishedVersio

Neurological diseases in cattle caused by plants and mycotoxins in Santa Catarina state, Brazil

ABSTRACT: This study described the epidemiological and clinical-pathological aspects of 25 outbreaks of neurological diseases in cattle caused by plants and mycotoxins in Santa Catarina state. Six of them were due to Sida carpinifolia poisoning, five to Solanum fastigiatum, five to Phalaris angusta, three to Claviceps paspali, three to Claviceps purpurea, and three outbreaks were of unknown etiology. The clinical signs observed in the affected cattle were mild to severe and characterized by generalized muscle tremors, incoordination, hypermetria, wide-based stance, intentional head tremors, dull staring eyes, and frequent ear twitching, with convulsions in some cases. At necropsy, lesions were observed only for P. angusta poisoning, characterized by gray-greenish discoloration in thalamus and midbrain. Microscopically, rarefaction and/or disappearance of Purkinje neurons with substitution by Bergmann cells were observed for S. carpinifolia and S. fastigiatum poisoning. For P. angusta poisoning, thin granular brown-yellowish pigment was observed in the cytoplasm of some neurons. Gross and microscopic findings were not observed in three outbreaks of tremorgenic disease of unknown etiology. Experiments conducted with leaves, flowers and seeds of Ipomoea indivisa and Ipomoea triloba, as well as with maize and soybean residues contaminated with Ipomoea spp. did not reproduced clinical signs

Lesões podais em ovinos da Mesorregião Sudoeste do Rio Grande do Sul

RESUMO: Lesões podais em ovinos são causas importantes de perdas econômicas por quedas na produtividade, na reprodução, por gastos com tratamentos ineficientes e com o descarte de animais afetados. Dessa forma, os objetivos foram descrever as principais características das lesões podais observadas em ovinos da Mesorregião Sudoeste do Rio Grande do Sul, seus aspectos epidemiológicos e a importância da ocorrência desses distúrbios para a criação de ovinos nessa região. Foram coletados dados epidemiológicos e clinicopatológicos de rebanhos ovinos da região entre abril de 2014 e abril de 2015 através de visitas técnicas em propriedades rurais. Foram avaliados rebanhos ovinos em 27 propriedades rurais localizadas em diferentes municípios, dos quais 21 registraram a ocorrência de lesões podais com relato de perdas econômicas significativas. Aproximadamente 1.700 ovinos, em média 10% dos rebanhos, apresentavam diferentes graus de claudicação decorrente de lesões podais que variavam de brandas a severas. Verificou-se que diversos fatores como clima e manejo foram favoráveis para o desenvolvimento das lesões podais e essas podem estar associadas a diferentes distúrbios e agentes etiológicos. No entanto, embora essas condições sejam importantes, o controle e a prevenção tem se mostrado ineficientes. Observou-se ainda que a pododermatite infecciosa dos ovinos (Footrot), parece ser a principal doença podal na região e atualmente pode ser considerada uma doença negligenciada

Cyanogenic poisoning by spontaneous ingestion of star grass (Cynodon nlemfuensis var. nlemfuensis cv. ‘Florico’) in cattle

ABSTRACT: This study reports the epidemiological data and the clinical-pathological condition of five outbreaks of cyanogenic poisoning in cattle spontaneously ingesting star grass (Cynodon nlemfuensis Vanderyst var. nlemfuensis cv. ‘Florico’). In all outbreaks, the areas where the plant was previously fertilized with high concentrations of nitrogen and the properties adopted the silvipastoral system. The first clinical signs appeared between 10 and 15 minutes after the first introduction of cattle and were characterized by muscular tremors, dyspnea, moderate tympanism, staggering gait, forced breathing with open mouth, sternal recumbency followed by death after 15 to 30 minutes and/or recovery in a few hours after the signs started. In total, 43 cows have become ill and 18 died. Two necropsies were performed and no significant changes were found except for the presence of the plant near the esophageal sphincter region. No histological lesions were seen through microscopy. Green leaves of the star grass were collected from all properties where the outbreaks occurred and the test of the picro-sodium paper was performed, revealing red-brick coloration in 20 minutes after maceration of the leaves

Aspectos epidemiológicos, clínico-patológicos e diagnóstico precoce da seneciose bovina no Oeste do Rio Grande do Sul

RESUMO: A ingestão de Senecio spp. (maria-mole) é, possivelmente, a principal causa de morte de bovinos por agentes tóxicos nas regiões central e sul do Rio Grande do Sul. Ao considerar a limitação de informações acerca dessa condição no Oeste do Rio Grande do Sul, esse trabalho objetiva descrever os principais aspectos epidemiológicos e clínico-patológicos da seneciose em bovinos nessa região. O estudo foi realizado por meio da aplicação de questionários em 16 propriedades rurais de municípios da região que apresentaram casos suspeitos da intoxicação em bovinos, de agosto de 2011 a março de 2014. Durante as visitas as propriedades foram coletadas plantas do gênero Senecio para identificação botânica, bem como se procedeu a coleta de fragmentos de fígado através de biópsia transtorácica para confirmação da intoxicação. As espécies de Senecio mais frequentes nas propriedades foram S. brasiliensis e S. heterotrichius. De um total de 88 bovinos, de nove propriedades distintas, que apresentaram falha no ganho de peso, 69 animais (aproximadamente 80%) foram positivos para seneciose crônica por apresentarem lesões características da intoxicação, tais como fibrose periportal (78% dos casos), megalocitose (76% dos casos) e proliferação de ductos biliares (68% dos casos), classificadas entre discretas e acentuadas. O trabalho confirmou a ocorrência da doença, mesmo em bovinos sem sinais clínicos evidentes. Os resultados obtidos nessas avaliações foram fundamentais para orientar proprietários e técnicos quanto às principais características da doença e às formas de controle a serem adotadas. O emprego da biópsia hepática possibilitou o diagnóstico precoce da intoxicação e auxiliou os criadores quanto ao descarte mais criterioso de bovinos e a real situação da intoxicação no rebanho, minimizando as perdas econômicas

Chlorhexidine digluconate on chitosan-magnetic iron oxide nanoparticles modified electrode: Electroanalysis and mechanistic insights by computational simulations

In this work, an electrochemical sensor based on modification of a glassy carbon electrode (GCE) with magnetic iron oxide nanoparticles (Fe3O4) and chitosan (CS) was developed to quantify chlorhexidine digluconate (CHD), a worldwide used antiseptic. Cyclic voltammetric and electrochemical impedance spectroscopy assays showed that the permeable Fe3O4/CS film on the GCE surface improved the conduc-tivity and facilitated electron transfer. CHD response at GCE/Fe3O4/CS corresponds to an irreversible anodic diffusion-controlled process (at about 1.13 V in 0.04 mol L−1 Britton-Robinson buffer, pH 4.0) involving the transfer of two electrons and an equal number of proton. Quantum mechanics and Monte Carlo simulations were performed to give insights on the CHD oxidation process. The modification with Fe3O4/CS induced alterations in CHD geometry that led to degeneration of the highest occupied molecular orbitals (HOMO and HOMO−1), facilitating the oxidation process because both sides of the molecule contribute to these orbitals. It facilitated also, at least thermodynamically, the first electron lost. The oxidation of CHD probably conducts to the formation of two p-chloroaniline and, possibly, two biguanidine molecules. GCE/Fe3O4/CS exhibited suitable electroanalytical characteristics in terms of sensitivity (8.78 ± 0.58 A mol−1 L), linearity range (2.10 × 10−8–2.09 × 10−7 mol L−1), detection limit (5.7 × 10−9 mol L−1; 0.005 mg kg−1), intra-day repeatability (2.8% RSD), and reproducibility (4.6% RSD). To evaluate the accuracy and applicability of the proposed electroanalytical methodology, two CHD com-mercial formulations were analysed and the attained results were in agreement with those attained by the chromatographic reference method. Overall, the developed GCE/Fe3O4/CS exhibits appropriate performance and relevant advantages for CHD electroanalysis in commercial products.info:eu-repo/semantics/publishedVersio