To send content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about sending content to .
To send content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about sending to your Kindle.
Note you can select to send to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be sent to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Chagas disease (CD) is a neglected parasitic condition endemic in the Americas caused by Trypanosoma cruzi. Patients present an acute phase that may or not be symptomatic, followed by lifelong chronic stage, mostly indeterminate, or with cardiac and/or digestive progressive lesions. Benznidazole (BZ) and nifurtimox are the only drugs approved for treatment but not effective in the late chronic phase and many strains of the parasite are naturally resistant. New alternative therapy is required to address this serious public health issue. Repositioning and combination represent faster, and cheaper trial strategies encouraged for neglected diseases. The effect of imatinib (IMB), a tyrosine kinase inhibitor designed for use in neoplasias, was assessed in vitro on T. cruzi and mammalian host cells. In comparison with BZ, IMB was moderately active against different strains and forms of the parasite. The combination IMB + BZ in fixed-ratio proportions was additive. Novel 14 derivatives of IMB were screened and a 3,2-difluoro-2-phenylacetamide (3e) was as potent as BZ on T. cruzi but had low selectivity index. The results demonstrate the importance of phenotypic assays, encourage the improvement of IMB derivatives to reach selectivity and testify to the use of repurposing and combination in drug screening for CD.
Ten new species of Trypetheliaceae are described: Astrothelium bullatothallinum from Venezuela, which is close to A. aeneum but differs by the bullate thallus with a thick cortex, intermixed in a mosaic with the prothallus; A. cayennense from French Guiana, which is similar to A. flavomegaspermum but with a yellow pigment in the pseudostroma near the ostioles; A. diaphanocorticatum from Papua New Guinea, which has a bullate thallus with a thick hyaline cortex and 3-septate ascospores of 25–28×10–12 μm; A. macroeustomum from French Guiana, with joint lateral ostioles, UV+ yellow ostiolar region and 5-septate ascospores of 50–55×12–17 μm; A. minicecidiogenum from Costa Rica, with muriform ascospores of 70–90×20–25 μm, without pseudostromata, with solitary ascomata, lateral ostioles and an inspersed hamathecium; A. palaeoexostemmatis from Thailand, which is similar to A. exostemmatis but with larger, I+ blue ascospores; A. quasimamillanum from Brazil, with muriform ascospores of 30–33×9·5–10·5 μm, without pseudostromata, with solitary ascomata, lateral ostioles and an inspersed hamathecium; A. studerae from Brazil, with astrothelioid ascomata, lichexanthone only in the pseudostromata, 3-septate ascospores of 21·5–23·0×6·5–7·5 μm; A. tanianum from Malaysia, with a bullate thallus, solitary ascomata, covered by the thallus, (9–)11(–15)-septate ascospores, 75–100×20–22 μm; and Pseudopyrenula miniflavida from Brazil, with a yellow-inspersed hamathecium, the inspersion dissolving in KOH without colour change, and 3-septate ascospores, 15–17×5·5–6·5 μm. The unusually thick, hyaline cortical layer of the thallus of Astrothelium diaphanocorticatum, through which the individual algal cells are clearly visible, is discussed. Furthermore, 30 species are reported from 34 countries in which they had previously been unrecorded; one (Astrothelium inspersaeneum) is from a new continent, Asia.
Three new species of the Neotropical genus Barbacenia (Velloziaceae, Pandanales) from Tocantins, Brazil, are described and illustrated, based on morphology and leaf anatomy. The known species richness of the genus is mapped within the countries of South America and the states of Brazil.
The Roosevelt–Rondon Expedition marmoset Mico marcai was first collected in 1914 and all information on this primate previously came from three skins brought back by this expedition. As a result, M. marcai is categorized as Data Deficient on the IUCN Red List. As the presumed range of M. marcai lies on the path of the advancing arc of deforestation in Brazil, the collection of relevant data to assess the conservation status of this Amazonian species is of some urgency. Here we present the first field data on the distribution and population size of, and threats to, M. marcai, to reassess the species’ conservation status. During 2012–2015 we surveyed the species in the Marmelos–Aripuanã interfluve, and estimated its density using distance sampling. We also used spatial predictive modelling to estimate forest loss within the species range under two deforestation scenarios. We found the marmoset in 13 localities and estimated its extent of occurrence to be 31,073 km2. We estimated the species’ density to be 8.31 individuals/km2 and extrapolated this to estimate a total population of 258,218 individuals (CI 150,705–441,860). Under a business-as-usual deforestation scenario, c. 10,000 km2 of forest, comprising 33% of the species’ range, would be lost in three marmoset generations (c. 18 years), and we, therefore, recommend that M. marcai be categorized as Vulnerable on the IUCN Red List based on criterion A3c. Other Amazonian marmosets require similar reassessment as their ranges also fall in the path of the arc of deforestation.
Atom probe tomography (APT) is rising in influence across many parts of materials science and engineering thanks to its unique combination of highly sensitive composition measurement and three-dimensional microstructural characterization. In this invited article, we have selected a few recent applications that showcase the unique capacity of APT to measure the local composition at structural defects. Whether we consider dislocations, stacking faults, or grain boundary, the detailed compositional measurements tend to indicate specific partitioning behaviors for the different solutes in both complex engineering and model alloys we investigated.
The influence of the concentration of carbon black nanoparticles on the mechanical behavior of a structural adhesive was studied to evaluate and understand the stiffness, strength, and deformation behavior of a reinforced epoxy adhesive. Two carbon black nanoparticles with different dielectric properties and sizes (Monarch® 120 and Vulcan® XC72R) were studied. A bi-component structural epoxy adhesive was selected. Specimens with different concentrations of carbon black were manufactured (0, 5, 10, and 20% on volume of resin) for each type of nanoparticle. The specimens were cured in a hydraulic hot-plates press machine. The mechanical behavior of the adhesives was found not to vary significantly as a function of carbon black nanoparticles amount. A scanning electron microscopy analysis was performed to evaluate the fracture surface. The fracture surfaces of specimens were correlated with the mechanical response obtained through tensile tests.
Eight new species of Pyrenulaceae are described as new to science from Brazil, Guyana and Puerto Rico. Pyrenula sanguineomeandrata Aptroot & Mercado Diaz (with a thallus with red, KOH+ purple pigmentation of lines or a reticulum, simple ascomata with vertical ostioles, a deep red inspersed, KOH+ orange hamathecium, and dark brown 3-septate ascospores 25–29×10–12 μm) and P. sanguineostiolata Aptroot & Mercado Diaz (with a thallus with deeply immersed simple ascomata with vertical ostioles, which are superficial and bright red, and 3-septate ascospores 25–28×9–12 μm) are described from submontane evergreen forests in Puerto Rico. Pyrenula biseptata Aptroot & M. Cáceres (with simple ascomata with vertical ostioles, an inspersed hamathecium and 2-septate ascospores 11–12×4·5–5·0 μm) and P. xanthinspersa Aptroot & M. Cáceres (with an ecorticate thallus containing lichexanthone, simple ascomata with vertical ostioles, not inspersed hamathecium and 3-septate ascospores 14–17×6·0–7·5 μm) are described from rainforest in Amazonian Brazil. Pyrenula subvariabilis Aptroot & Sipman (with fused ascomata with lateral ostioles and submuriform ascospores 17–20(–25)×6–9 μm) and Sulcopyrenula biseriata Aptroot & Sipman (with a thallus containing lichexanthone, simple ascomata with lateral ostioles and lozenge-shaped ascospores with 8 locules, (13–)15–17(–20)×8–10 (width)×6–7 (thickness) μm) are described from savannahs in Guyana. Special attention is paid to the genus Pyrgillus: two new species from the 3-septate core group of this small genus are described from Brazil, viz. P. aurantiacus Aptroot & M. Cáceres (with a corticate thallus containing lichexanthone, mazaedium with orange, KOH+ violet, UV+ red pruina and ascospores of 13–16×6·0–7·5 μm) and P. rufus Aptroot & M. Cáceres (with a corticate thallus containing lichexanthone, mazaedium with dark red, KOH+ orange, UV+ red pruina and ascospores of 15·0–17·5×5·0–6·5 μm). An updated key to the 3-septate species of Pyrgillus is provided.
Phosphorus (P) is an essential nutrient in livestock production, involved in most metabolic processes in the body, and with an impact on bone development and growth. Diet supplementation with P can improve productivity, but at excess levels the P utilization can be low, and the high P excretion will lead to environmental pollution (Tamminga, 2003). P supplementation also adds substantially to the cost of feed. Using the isotopic dilution technique (Vitti et al., 2000), we have studied the effect of different P levels in diet on P absorption and excretion in Brazilian sheep, and identified the level at which true P absorption saturates.
It is a general believe that the local sheep breed Churra da Terra Quente (CTQ), reared in the Northeast of Portugal is well adapted to the conditions of its production system. However, there are large gaps on our knowledge to allow understanding of such claimed adaptation. Several researchers have found differences in digestibility between sheep breeds (e.g. Givens and Moss, 1994; López et al., 2001), suggesting that those fed natural resources can have an improved ability to digest fibre. This experiment was designed to compare digestibility coefficients of a high– and a low–roughage diet measured on sheep from CTQ and Ile-de-France (IF) breeds at the same degree of maturity.
In Northeast of Portugal sheep is reared under extensive systems. These systems frequently involve expressive body composition changes due to the storing and mobilization of body reserves, mainly fat. Body condition score (BCS) is the most common way to assess these reserves and the nutritional status of ewes. However due to the subjective nature of BCS, their quality has been questioned and other alternatives has been studied. For cattle there are some studies that use the real time ultrasonography (RTU) to evaluate the BCS (Schwager-Suter et al., 2000; Broring et al., 2003), but this approach was not tested in ewes. Therefore the aim of the present study was to establish a relationship between the BCS and ultrasound subcutaneous fat (SF) and Longissimus thoracis et lumborum muscle (LM) measurements.
Urban slums provide suitable conditions for infestation by rats, which harbour and shed a wide diversity of zoonotic pathogens including helminths. We aimed to identify risk factors associated with the probability and intensity of infection of helminths of the digestive tract in an urban slum population of Rattus norvegicus. Among 299 rats, eleven species/groups of helminths were identified, of which Strongyloides sp., Nippostrongylus brasiliensis and, the human pathogen, Angiostrongylus cantonensis were the most frequent (97, 41 and 39%, respectively). Sex interactions highlighted behavioural differences between males and females, as eg males were more likely to be infected with N. brasiliensis where rat signs were present, and males presented more intense infections of Strongyloides sp. Moreover, rats in poor body condition had higher intensities of N. brasiliensis. We describe a high global richness of parasites in R. norvegicus, including five species known to cause disease in humans. Among these, A. cantonensis was found in high prevalence and it was ubiquitous in the study area – knowledge which is of public health importance. A variety of environmental, demographic and body condition variables were associated with helminth species infection of rats, suggesting a comparable variety of risk factors for humans.
Cyclospora cayetanensis is a coccidian parasite associated with diarrheal illness. In the USA, foodborne outbreaks of cyclosporiasis have been documented almost every year since the mid-1990s. The typical approach used to identify this parasite in human stools is an examination of acid-fast-stained smears under bright-field microscopy. UV fluorescence microscopy of wet mounts is more sensitive and specific than acid-fast staining but requires a fluorescence microscope with a special filter not commonly available in diagnostic laboratories. In this study, we evaluated a new DNA extraction method based on the Universal Nucleic Acid Extraction (UNEX) buffer and compared the performances of four published real-time polymerase chain reaction (PCR) assays for the specific detection of C. cayetanensis in stool. The UNEX-based method had an improved capability to recover DNA from oocysts compared with the FastDNA stool extraction method. The best-performing real-time PCR assay was a C. cayetanensis-specific TaqMan PCR that targets the 18S ribosomal RNA gene. This new testing algorithm should be useful for detection of C. cayetanensis in human stool samples.
The scaling of turbulent motions is investigated by considering the flow in the eigenframe of the local strain-rate tensor. The flow patterns in this frame of reference are evaluated using existing direct numerical simulations of homogeneous isotropic turbulence over a Reynolds number range from
up to 1131, and also with reference to data for inhomogeneous, anisotropic wall turbulence. The average flow in the eigenframe reveals a shear layer structure containing tube-like vortices and a dissipation sheet, whose dimensions scale with the Kolmogorov length scale,
. The vorticity stretching motions scale with the Taylor length scale,
, while the flow outside the shear layer scales with the integral length scale,
. Furthermore, the spatial organization of the vortices and the dissipation sheet defines a characteristic small-scale structure. The overall size of this characteristic small-scale structure is
in all directions based on the coherence length of the vorticity. This is considerably larger than the typical size of individual vortices, and reflects the importance of spatial organization at the small scales. Comparing the overall size of the characteristic small-scale structure with the largest flow scales and the vorticity stretching motions on the scale of
shows that transitions in flow structure occur where
and 250. Below these respective transitional Reynolds numbers, the small-scale motions and the vorticity stretching motions are progressively less well developed. Scale interactions are examined by decomposing the average shear layer into a local flow, which is induced by the shear layer vorticity, and a non-local flow, which represents the environment of the characteristic small-scale structure. The non-local strain is
in width and height, which is consistent with observations in high Reynolds number flow of a
wide instantaneous shear layer with many
-scale vortical structures inside (Ishihara et al., Flow Turbul. Combust., vol. 91, 2013, pp. 895–929). In the average shear layer, vorticity aligns with the intermediate principal strain at small scales, while it aligns with the most stretching principal strain at larger scales, consistent with instantaneous turbulence. The length scale at which the alignment changes depends on the Reynolds number. When conditioning the flow in the eigenframe on extreme dissipation, the velocity is strongly affected over large distances. Moreover, the associated peak velocity remains Reynolds number dependent when normalized by the Kolmogorov velocity scale. It signifies that extreme dissipation is not simply a small-scale property, but is associated with large scales at the same time.
The main objective of this work was to evaluate technologies that have potential for monitoring aspects related to spatial and temporal variability of soil nutrients and pasture yield and for support to decision making by the farmers. Three types of sensors were evaluated: an electromagnetic induction sensor, an active optical sensor and a capacitance probe. The results are relevant for the selection of the adequate sensing system for each particular application and to open new perspectives for other works that would allow the testing, calibration and validation of the sensors in a wider range of pasture production conditions and rainfall patterns, characteristic of the Mediterranean region.
Plants’ ability to rebuild their tiller population is affected by weather changes and management strategies. The hypothesis of the present study was that frequency and severity of defoliation alter Mulato grass (Brachiaria ruziziensis × Brachiaria brizantha cv. Marandu) sward development, and the proportion of aerial and basal tillers, interfering with sward stability. The objective was to evaluate aerial, basal and total tiller population density and changes in tillering dynamics. Treatments corresponded to strategies of rotational grazing characterized by combinations between two pre-grazing (95% and maximum canopy light interception during regrowth; LI95% and LIMax) and two post-grazing conditions (15 and 20 cm stubble height). The experimental period comprised four seasons of the year: summer 2008 (February–March 2008); autumn–early spring (April to mid-November 2008); late spring (mid-November–December 2008); and summer 2009 (January–March 2009). Density of aerial tillers decreased from summer 2008 to late spring. Tiller death decreased from summer 2008 to autumn–early spring. Aerial and total tiller death increased from late spring to summer 2009, mainly for the LI95% treatment. No differences were observed in the tiller population stability index of aerial tillers for LI treatments or post-grazing heights. The balance between tiller appearance and death for basal tillers remained relatively stable from summer 2008 to late spring. For aerial tillers the balance decreased to negative values from summer 2008 to autumn–early spring for both LI treatments. For total tiller population, the balance decreased to negative values from summer 2008 to autumn–early spring. Results indicated a strong seasonal effect on Mulato grass tillering and growth. Tillering dynamics were affected primarily by grazing frequency, which changed the relative importance of basal and aerial tillers. The results suggested that basal tillering was the predominant perennation pathway.
Several studies have shown that maternal low-protein (LP) diet induces detrimental effects in cardiovascular system and oxidative stress in male animals. Additional studies suggested that female has lower incidence of cardiovascular disease. However until present data, the possible effects of estradiol on the undernutrition during gestational and lactation periods are not discussed. The present study was conducted to evaluate the effects of a maternal LP diet during gestational and lactation period on oxidative balance in the female rat hearts ventricles at two ages. Dams were fed with normal protein (NP) or a LP diet during the gestational and lactation period, and their female offspring were divided into age groups (22 or 122 days, corresponding to a low or high estrogen level) composing four experimental groups. Evaluating the nutritional effect showed an increase in oxidative stress biomarkers and decrease in enzymatic defense in LP-22D compared with NP-22D. In contrast, no changes were observed in malondialdehyde and carbonyls, but an increase in glutathione-S-transferase (GST) activity in the LP-122D compared with NP-122D. The global oxy-score in the LP-22D group indicated a predominance of oxidative damage when compared with NP-22D, while in LP-122D group the global oxy-score was restored to NP-122D levels. Evaluating the estradiol effect, our data show a significant decrease in oxidative stress with increase in CAT and GST activity, associated with increase in intracellular thiols. Our data suggest that in situation with low levels of estradiol, hypoproteic diet during gestation and lactation period has detrimental effects on heart, however when estradiol levels raise, the detrimental effects induced are mitigated.
X-ray diffraction (XRD), transmission Mössbauer spectroscopy, and vibrating sample magnetometry were used to study the influence of precipitates on the magnetic properties of aged Fe–Cr–Mo alloys. XRD patterns and Mössbauer spectra showed that the alloys have body-centered cubic structure similar to that of α-Fe. Small amounts of precipitates were also identified with relative fraction found to be related to Mo content, aging times, and temperatures. Magnetic measurements showed that the increase in the density of precipitates contributes significantly to the increase in the magnetic hardness of the material. This mechanism is related to a process of pinning of magnetic domain walls. It was also found that saturation magnetization is affected by the Mo content in the alloy. The techniques used in this work were shown to be very useful to understand the mechanisms through which the formation of precipitates affects the magnetic properties of the alloys and may be used as complement to the usual microscopy-based techniques for this purpose.
The primary causative agent of eosinophilic meningoencephalitis (EoM) in endemic regions is the nematode Angiostrongylus cantonensis. The occurrence of EoM was previously restricted to countries in Southeast Asia and the Pacific Islands; however, more recently, it has been reported from other regions, including Brazil. The commonly used diagnosis is detection of specific antibody reactivity to the 31 kDa antigen, which is derived from female worm somatic extracts. Here we report the occurrence of cross-reactivity to this antigen in sera from other parasitic infections, especially those that may cause EoM, such as gnathostomiasis, toxocariasis, hydatidosis and strongyloidiasis. We also demonstrated that the cross-reactivity, in part, is dependent of the concentration of antigen used in Western blot assays. We discuss the importance of these findings on the interpretation of this test.