Passive direct methanol fuel cells acting as fully autonomous electrochemical biosensors: Application to sarcosine detection

This work describes an innovative electrochemical biosensor that advances its autonomy toward an equipment-free design. The biosensor is powered by a passive direct methanol fuel cell (DMFC) and signals the response via an electrochromic display. Briefly, the anode side of the DMFC power source was modified with a biosensor layer developed using molecularly imprinted polymer (MIP) technology to detect sarcosine (an amino acid derivative that is a potential cancer biomarker). The biosensor layer was anchored on the surface of the anode carbon electrode (carbon black with Pt/Ru, 40:20). This was done by bulk radical polymerization with acrylamide, bis-acrylamide, and vinyl phosphonic acid. This layer selectively interacted with sarcosine when integrated into the passive DMFC (single or multiple, in a stack of 4), which acted as a transducer element in a concentration-dependent process. Serial assembly of a stack of hybrid DMFC/biosensor devices triggered an external electrochromic cell (EC) that produced a colour change. Calibrations showed a concentration-dependent sarcosine response from 3.2 to 2000 µM, which is compatible with the concentration of sarcosine in the blood of prostate cancer patients. The final DMFC/biosensor-EC platform showed a colour change perceptible to the naked eye in the presence of increasing sarcosine concentrations. This colour change was controlled by the DMFC operation, making this approach a self-controlled and self-signalling device. Overall, this approach is a proof-of-concept for a fully autonomous biosensor powered by a chemical fuel. This simple and low-cost approach offers the potential to be deployed anywhere and is particularly suitable for point-of-care (POC) analysis.The authors acknowledge the financial support of EU-Horizon 2020 (Symbiotic, FET-Open, GA665046), and from national funds from FCT - Fundação para a Ciência e a Tecnologia, I.P., in the scope of the projects LA/P/0037/2020, UIDP/50025/2020, UIDB/50025/2020 and UID/EMS/00532/2019. Nádia Ferreira (SFRH/BD/122955/2016), Liliana Carneiro (SFRH/BD/122954/2016), and Ana Carolina Marques (SFRH/BD/115173/2016) acknowledge Fundação para a Ciência e Tecnologia (FCT) for financial support.info:eu-repo/semantics/publishedVersio

Levantamento fitossociológico de plantas daninhas em cafezal orgânico.

A adequação de um cafezal para o sistema orgânico causa grande mudança no sistema de manejo de plantas daninhas, mas as informações sobre o comportamento da comunidade infestante em áreas de cultivo de café orgânico são escassas no Brasil. Objetivou-se com este trabalho realizar um levantamento fitossociológico da comunidade infestante em três cafezais (variedades Mundo Novo, Bourbon Vermelho e Obatã) desenvolvidos em sistema orgânico, no município de Garça (SP). Nas três áreas estudadas foram arremessados ao acaso cem quadrados metálicos com área vazada de 0,25 m2, nas entrelinhas da cultura. As espécies contidas no interior dos quadros foram identificadas segundo a espécie botânica, nome popular e família. A partir dos resultados, determinaram-se os parâmetros fitossociológicos: frequência, densidade, abundância, frequência relativa, densidade relativa, abundância relativa, índice de valor de importância e similaridade florísticas pelos métodos de Simple Matching de Sneath & Sokal e similaridade de Sorensen. As famílias que mais se destacaram, com maior número de espécies nas três áreas foram Poaceae e Asteraceae. Houve alta similaridade em todos os contrastes testados, já que pelo menos metade das espécies identificadas foi comum às duas áreas contrastadas

Diversidade de angiospermas e espécies medicinais de uma área de Cerrado

RESUMO Este trabalho teve como objetivo conhecer a diversidade vegetal de uma área de Cerrado em Prudente de Morais, MG, bem como suas indicações medicinais. Foram feitas nove excursões à reserva da Fazenda Experimental Santa Rita da Empresa de Pesquisa Agropecuária de Minas Gerais (FESR/EPAMIG) (19°26’20”’ S e 44°09’15”’ W). O material vegetal coletado foi herborizado, identificado e incorporado ao acervo do Herbário PAMG/EPAMIG. O sistema de classificação utilizado foi o APG III. Após a identificação, realizou-se uma pesquisa bibliográfica buscando dados sobre a utilização medicinal das espécies. Coletaram-se 108 espécies pertencentes a 47 famílias. As famílias mais representativas foram: Fabaceae, com 16 espécies, Myrtaceae com sete espécies, Asteraceae e Rubiaceae com seis espécies cada, Malpighiaceae e Solanaceae com cinco espécies cada, Erythroxylaceae, Euphorbiaceae e Vochysiaceae, com quatro espécies cada, Anacardiaceae, Apocynaceae, Lamiaceae e Sapindaceae com três espécies cada, Annonaceae, Arecaceae, Bignoniaceae, Celastraceae e Primulaceae com duas espécies cada. Vinte e nove famílias foram monoespecíficas. Das 108 espécies, 39 são árvores (36%), 43 arbustos (40%), seis subarbustos (5,5%), 14 lianas (13%) e seis são ervas (5,5%). Sessenta e seis (61%) espécies pertencentes a 39 famílias (83%) são utilizadas popularmente, para o tratamento de alguma doença. As famílias com maior número de espécies medicinais foram: Fabaceae com oito espécies; Rubiaceae com cinco espécies e Solanaceae com quatro espécies. As espécies que apresentaram mais finalidades terapêuticas foram: Brosimum gaudichaudii Trécul (Moraceae), Caryocar brasiliense Cambess. (Caryocaraceae), Cochlospermum regium (Mart. ex Schrank) Pilg. (Bixaceae), Croton urucurana Bail. (Euphorbiaceae), Gomphrena officinalis Mart. (Amaranthaceae), Hymenaea stigonocarpa Mart. ex Hayne (Fabaceae), Lithrea molleoides (Vell.) Engl. (Anacardiaceae), Myracrodruon urundeuva Allemão (Anacardiaceae) e Randia. armata (Sw.) DC. (Rubiaceae). As finalidades terapêuticas que apresentaram maior número de espécies foram: tônico (15 spp., 22,7%), afecções do aparelho respiratório (13 spp., 19,6%), afecções da pele (12 spp., 18%) e febres (12 spp., 18%). O conhecimento tradicional sobre as plantas medicinais do cerrado deve ser mais investigado para que seja preservado, valorizado, e para que medidas conservacionistas sejam tomadas evitando que essas plantas desapareçam antes que sua utilização tradicional seja corroborada pela ciência

Cálculo De Elastância Em Curvas Pressão-volume Em Pulmões Lesados Por Paraquat: Modelo De Lesão Pulmonar Aguda

Acute lung injury, whose most severe expression is Respiratory Distress Syndrome, was described 40 years ago. Despite all research in this field, mortality rate still remains around 35%. In this study we used a model of acute lung injury with paraquat, an herbicide that causes alveolar instability through destruction of surfactant, to obtain pressure-volume curves of lungs in open-chest rats. The objectives were to study acute lung injury through measurements of lung elastance during inspiratory and expiratory maneuvers. We observed a rise in elastance during the initial part of the inspiratory maneuver (0-5mL approx.) in animals exposed to paraquat possibly due to increased alveolar collapse. We suppose that alveolar recruitment is responsible for the absence of significant elastance changes in other phases of the inspiratory maneuver. © 2013 Springer.33 IFMBE212215SKAN AG,Materialise NV,Bavarian Minist. Econ., Aff., Infrastruct., Transp. Technol.,Bavarian Bureau for International Business Relations GmbH,AKUD - Med Pharm GmbHMacIntyre, N.R., Is there a best way to set positive expiratory-end pressure for mechanical ventilatory support in acute lung injury? (2008) Clin Chest Med, 29, pp. 233-239Erickson, S.E., Martin, G.S., Davis, J.L., Mathay, M.A., Eisner, M.D., Recent trends in acute lung injury mortality: 1996-2005* (2009) Crit Care Med, 37, pp. 1574-1579. , MDMD, MScMDMDMD, MPHfor the NIH NHLBI ARDS NetworkMatute-Bello, G., Frevert, C.W., Martin, T.R., Animal models of acute lung injury J Physiol Lung Cell Mol Physiol, 295, pp. 379-399. , doi:10.1152/ajplung.00010.2008Silva, M.F.R., Saldiva, P.H.N., Paraquat poisoning: An experimental model of dose-dependent acute lung injury due to surfactant dysfunction (1998) Brazilian Journal of Medical and Biological Research, 31 (3), pp. 445-450Silva, M.F.R., Zin, W.A., Saldiva, P.H.N., Airspace configuration at different transpulmonary pressures in normal and paraquat-induced lung injury in rats (1998) American Journal of Respiratory and Critical Care Medicine, 158 (4), pp. 1230-123

Digestibilidade de dietas e metabolismo de suínos alimentados com dietas contendo extratos cítricos

An experiment was carried out to evaluate the digestibility of diets, and metabolism of finishing pigs fed diets containing citric extracts. Twelve barrows with average initial weight of 54 kilograms were used. A completely randomized experimen- tal design was used, with two treatments (control diet and control diet + 750mg . kg -1 of a compound of citric extracts, containing ascorbic acid and bioflavonoids) with six replications, and the animal as an experimental unit. The citric extracts did not alter (p>0.05) nitrogen balance, but increased (p<0.05) in 3.56 % the retained energy and in 1.94 % the digestible energy. Pigs fed diets containing citrus extracts had decreased (p<0.05) from 12.9 % in the level of blood cholesterol. The addition of citric extracts in diets for pigs improves the retention of energy, the use of digestible energy and reduces the plasma cholesterol levels.O experimento foi realizado com o objetivo de avaliar a digestibilidade das dietas e o metabolismo de suínos em terminação alimentados com dietas contendo extratos cítricos. Foram utilizados 12 suínos, machos castrados, com peso médio inicial de 54 quilogramas. O delineamento experimental foi inteiramente casualizado com dois tratamentos (dieta controle e dieta controle + 750 mg . kg -1 de um composto de extratos cítricos, contendo ácido ascórbico e bioflavonóides) de seis repetições cada, sendo o animal a unidade experimental. O uso de extratos cítricos não alterou (p>0,05) o balanço de nitrogênio, porém aumentou (p=0,05) em 3,56 % a energia retida e em (p<0,05) 1,94 % a energia digestível. Suínos alimentados com die- tas contendo extratos cítricos apresentaram redução (p<0,05) de 12,9 % no nível de colesterol sanguíneo. A adição de extratos cítricos em dietas para suínos melhora a retenção de energia, o aproveitamento da energia digestível e reduz os níveis plasmáticos de colesterol

New accuracy estimators for genomic selection with application in a cassava (Manihot esculenta) breeding program

Genomic selection is the main force driving applied breeding programs and accuracy is the main measure for evaluating its efficiency. The traditional estimator (TE) of experimental accuracy is not fully adequate. This study proposes and evaluates the performance and efficiency of two new accuracy estimators, called regularized estimator (RE) and hybrid estimator (HE), which were applied to a practical cassava breeding program and also to simulated data. The simulation study considered two individual narrow sense heritability levels and two genetic architectures for traits. TE, RE, and HE were compared under four validation procedures: without validation (WV), independent validation, ten-fold validation through jacknife allowing different markers, and with the same markers selected in each cycle. RE presented accuracies closer to the parametric ones and less biased and more precise ones than TE. HE proved to be very effective in the WV procedure. The estimators were applied to five traits evaluated in a cassava experiment, including 358 clones genotyped for 390 SNPs. Accuracies ranged from 0.67 to 1.12 with TE and from 0.22 to 0.51 with RE. These results indicated that TE overestimated the accuracy and led to one accuracy estimate (1.12) higher than one, which is outside of the parameter space. Use of RE turned the accuracy into the parameter space. Cassava breeding programs can be more realistically implemented using the new estimators proposed in this study, providing less risky practical inferences

The effect of nanotube surface oxidation on the electrical properties of multiwall carbon nanotube/poly(vinylidene ¿uoride) composites

Carbon nanotube/poly(vinylidene fluoride) (CNT/PVDF) composites were prepared using CNT with different oxidation and thermal treatments. The oxidation procedure leads to CNT with the most acidic characteristics that lower the degree of crystallinity of the polymer and contribute to a large increase of the dielectric constant. The surface treatments, in general, increase the percolation threshold and decrease conductivity. The surface treatments do not seem to affect CNT interactions and similar degrees of dispersion are achieved in all cases, as shown by the SEM results. The maximum value of the dielectric constant is ~630. It is demonstrated that the composite conductivity can be attributed to a hopping mechanism that is strongly affected by the surface treatment of the CNT.Peer Reviewe

Paraquat poisoning: an experimental model of dose-dependent acute lung injury due to surfactant dysfunction

Since the most characteristic feature of paraquat poisoning is lung damage, a prospective controlled study was performed on excised rat lungs in order to estimate the intensity of lesion after different doses. Twenty-five male, 2-3-month-old non-SPF Wistar rats, divided into 5 groups, received paraquat dichloride in a single intraperitoneal injection (0, 1, 5, 25, or 50 mg/kg body weight) 24 h before the experiment. Static pressure-volume (PV) curves were performed in air- and saline-filled lungs; an estimator of surface tension and tissue works was computed by integrating the area of both curves and reported as work/ml of volume displacement. Paraquat induced a dose-dependent increase of inspiratory surface tension work that reached a significant two-fold order of magnitude for 25 and 50 mg/kg body weight (P<0.05, ANOVA), sparing lung tissue. This kind of lesion was probably due to functional abnormalities of the surfactant system, as was shown by the increase in the hysteresis of the paraquat groups at the highest doses. Hence, paraquat poisoning provides a suitable model of acute lung injury with alveolar instability that can be easily used in experimental protocols of mechanical ventilatio