Environmental factors influencing the transmission of Haemonchus contortus

AbstractInfection with the gastrointestinal nematode Haemonchus contortus causes considerable losses in the sheep industry. In this study, we evaluated the effect that climate has on third-stage larvae (L3) of H. contortus in terms of their migration from sheep feces to Brachiaria decumbens grass, as well as their distribution among the forage plants. Fecal samples containing H. contortus L3 was deposited on the soil among the herbage at an initial height of 30cm. Sample collection began 24h after contamination and was performed on alternate days over 13 days. The L3 were recovered and quantified in three strata (heights) of grass (0–10cm, 10–20cm and >20cm) as well as in the remaining feces and a superficial layer of soil, collected from beneath the feces. In order to obtain results under different environmental conditions, fecal samples containing H. contortus L3 were deposited on pasture in January (summer), in April (autumn), and July (winter). In all of the periods, the L3 were able to migrate from the feces to the herbage. However, rains, accompanied by high relative humidity and high temperatures, apparently favored migration. The highest L3 recovery rate in the pasture was in the summer observation period, which had the highest number of days with measurable precipitation, high relative humidity (>68.2%), and the highest temperatures at the soil level (minimum and maximum means of 19°C and 42°C, respectively). Under those conditions, larvae began to reach the upper stratum of the grass (>20cm) by 24h after the deposition of fecal matter, the number of larvae having reached that stratum peaking at seven days after deposition. In the autumn observation period, there was no rainfall in the first five days post-contamination. During that period, high numbers of larvae were found in the fecal samples demonstrating that feces can act as a reservoir of larvae in the absence of rain. Except for two days in the summer observation period, when most of the L3 were recovered from the tops of blades of grass, L3 where located predominantly at the base of the herbage. In conclusion, rainfall favors the migration of L3 from feces to herbage. In addition, larval migration up and along blades of grass can occur relatively rapidly when the temperature is high

Influence of the concentrations of xanthan gum, hydroxypropyl starch and potassium chloride on the flow properties of drilling fluid formulations

Drilling operation of oil wells involves high costs and risks. With recent discoveries of deeper reservoirs and difficult to access, there was an increase in the number of horizontal wells drilled and far-reaching, and, thereat, new challenges with operational problems. Fluids, or muds, drilling are essential to the well drilling process, confirming the need to study and find physical, rheological, and filtration properties, appropriate to the complexities in each section and the drilling stage. Optimized formulation is the one that comprises a safe operation, mitigation of operational problems, environmental protection, low cost, and high productivity. Thus, this paper offers the study of the rheological properties, and determination of filtrate volume, of the aqueous base fluid formulations, developed with polymeric additives. A high performance formulation, presenting technical-economical feasibility for drilling operations, was achieved using 0.43% m/v of viscosifier (xanthan gun), 0.57% m/v of filtrate controller (hydroxypropyl starch) and 4.57% m/v of clay swelling inhibitor (KCl).La operación de perforación de pozos de petróleo implica altos costos y riesgos. Con los recientes descubrimientos de depósitos más profundos y de difícil acceso, hubo un aumento en el número de pozos horizontales perforados y de largo alcance y, por lo tanto, nuevos desafíos con problemas operacionales. Los fluidos o los lodos de perforación son esenciales para el proceso de perforación del pozo, confirmando la necesidad de estudiar y encontrar propiedades físicas, reológicas y de filtración, adecuadas a las complejidades de cada sección ya la fase de perforación. La formulación optimizada es aquella que comprende una operación segura, mitigación de problemas operacionales, protección ambiental, bajo costo y alta productividad. Así, este trabajo ofrece el estudio de las propiedades reológicas y de volumen de filtrado de las formulaciones de fluidos de base acuosa, desarrolladas con aditivos poliméricos. Una formulación de alto rendimiento, presentando viabilidad técnico-económica para operaciones de perforación, fue alcanzada utilizando 0,43% mv de viscosificante (goma xantana), 0,57% m / v de controlador de filtrado (hidroxipropilamido) y 4,57% m / v de inhibidor de la hinchazón de arcilla (KCl)

The effectiveness of voriconazole in therapy of Candida glabratas biofilms oral infections and its influence on the matrix composition and gene expression

Candida glabrata is one of most prevalente yeast in fungal infections, especially in immunocompromised patients. Its azole resistance results in a low therapeutic response, particularly when associated with biofilms. The main goal of this work was to study the effectiveness of voriconazole (Vcz) against C. glabrata biofilms oral pathologies, as esophageal or oropharyngeal candidiasis. Antifungal susceptibilities were determined in pre-formed 24-h-biofilms and ERG genes expression was determined by qRT-PCR. Protein quantification was performed using BCA Kit, carbohydrate was estimated according to the Dubois assay and b-1,3 glucans concentration were determined using Glucatell kit. Finally, ergosterol, Vcz, and fluconazole (Flu) concentrations within the bio-film matrices were determined by RP-HPLC. Results showed that C. glabrata biofilms were more susceptible to Vcz than to Flu and that ERG genes expression evidenced an overexpression of the three ERG genes in the presence of both azoles. The matrix content presented a remarked decrease in proteins and an increase in carbohydrates, namely b-1,3 glucans. Ergosterol was successfully detected and quantified in the biofilm matrices, with no differences in all the considered conditions. Vcz demonstrated better diffusion through the biofilms and better cell penetration capacities, than Flu, indicating that the structure of the drug molecule fully influences its dissemination through the biofilm matrices. This work showed that Vcz is notably more effective than Flu for the treatment of resistant C. glabrata oral biofilms, which demonstrates a clinical relevance in its future use for the treatment of oropharyngeal/esophageal candidiasis caused by this species.This work was supported by the Programa Operacional, Fatores de competitividade— COMPETE and by national funds through FCT—Fundação para a Ciência e a Tecnologia on the scope of the projects FCT [PTDC/SAU-MIC/119069/2010], [RECI/EBB-EBI/0179/2012], [PEst-OE/EQB/LA0023/2013] and Célia F. Rodrigues’ [SFRH/ BD/93078/2013] PhD Grant. The authors thank the Project ‘‘BioHealth—Biotechnology and Bioengineering approaches to improve health quality’’, Ref. NORTE-07-0124-FEDER000027, co-funded by the Programa Operacional Regional do Norte (ON.2—O Novo Norte), QREN, FEDER. The authors would like to acknowledge Pfizer, S.A. for the kindly donation of Voriconazole and Fluconazole.info:eu-repo/semantics/publishedVersio

Biosorption of hexavalent chromium based on modified Y zeolites obtained by alkali-treatment

The structural modification of external surface of NaY was investigated in order to enhance efficient biosorption systems consisting of a bacterial biofilm, Arthrobacter viscosus, supported on that zeolite, for removing hexavalent chromium from aqueous solutions. The supported bacterial biofilm reduces Cr(VI) to Cr(III) and this cation is then retained in the zeolite by ion exchange. NaY zeolite was modified by alkali-treatments using NaOH 2.0 M, with two different contact periods of time between the zeolite and the alkaline solutions, resulting in NaYA and in NaYB. The biosorbents supported on the modified NaY zeolite were tested in solutions with low concentration of chromium. The results showed that the modification of external surface of NaY zeolite allows an efficient Cr removal, and the maximum removal efficiency was observed for NaYA sample that was submitted to a smoother chemical treatment.The authors acknowledge to Dr. A.S. Azevedo for collecting the powder diffraction data and Dr. C Ribeiro, from Departamento de Ciencias da Terra of Universidade do Minho, for chemical analyses. This work was supported by Fundacao para a Ciencia e Tecnologia (FCT-Portugal), under program POCTI-SFA-3-686. H.F. and B.S. gratefully acknowledge FCT-Portugal for the PhD grants

Characterizing top gated bilayer graphene interaction with its environment by Raman spectroscopy

In this work we study the behavior of the optical phonon modes in bilayer graphene devices by applying top gate voltage, using Raman scattering. We observe the splitting of the Raman G band as we tune the Fermi level of the sample, which is explained in terms of mixing of the Raman (Eg) and infrared (Eu) phonon modes, due to different doping in the two layers. We theoretically analyze our data in terms of the bilayer graphene phonon self-energy which includes non-homogeneous charge carrier doping between the graphene layers. We show that the comparison between the experiment and theoretical model not only gives information about the total charge concentration in the bilayer graphene device, but also allows to separately quantify the amount of unintentional charge coming from the top and the bottom of the system, and therefore to characterize the interaction of bilayer graphene with its surrounding environment

Catalytic reutilization of chromium-loaded NaY oxidation of ethyl acetate

EUROPACAT IX - Catalysis for a Sustainable WorldThe aim of this study is the reutilization of new materials obtained by biorecovery of chromium from water, in catalytic oxidations of volatile organic compounds. A biosorption system consisting of a microorganism supported on a NaY zeolite was used to remove hexavalent chromium from contaminated water. After the biosorption process, the chromium-loaded zeolite was used as catalyst to be applied in catalytic oxidation of ethyl acetate. The results showed that a higher content of chromium enhanced the activity and the C0 2 selectivity of the catalystinfo:eu-repo/semantics/publishedVersio

A Change-Driven Image Foveation Approach for Tracking Plant Phenology

One of the challenges in remote phenology studies lies in how to efficiently manage large volumes of data obtained as long-term sequences of high-resolution images. A promising approach is known as image foveation, which is able to reduce the computational resources used (i.e., memory storage) in several applications. In this paper, we propose an image foveation approach towards plant phenology tracking where relevant changes within an image time series guide the creation of foveal models used to resample unseen images. By doing so, images are taken to a space-variant domain where regions vary in resolution according to their contextual relevance for the application. We performed our validation on a dataset of vegetation image sequences previously used in plant phenology studies

Os desafios na implanta??o de um projeto de horta escolar.

Este artigo consiste num relato de experi?ncia sobre hortas escolares desenvolvida em uma escola p?blica por bolsistas do subprojeto interdisciplinar em Ci?ncias do PIBID/UFOP. A horta foi eleita como uma estrat?gia para trabalhar conhecimentos cient?ficos e populares, de modo a favorecer a participa??o dos alunos e promover um ensino interdisciplinar. Entretanto, foram encontrados muitos desafios e obst?culos no in?cio do trabalho que exigiram pesquisas e busca de solu??es. Dessa forma, o artigo mostra como a atividade de planejamento se transformou em uma a??o investigativa por parte dos licenciandos e coordenadores do subprojeto