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1.
Childs Nerv Syst ; 40(6): 1949-1951, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38427107

RESUMEN

The ventriculoperitoneal shunt placement procedure is common throughout the world, with a prevalence of approximately 30,000 procedures per year in the United States (5). However, the rate of complications is still important and must be remembered, with a percentage of 11 to 25% after the first year of implantation. Abdominal complications are described in 5-47% of the cases (6), and the abdominal pseudocyst is one of them. We present the case of a patient colonized by multidrug-resistant bacteria, who underwent exteriorization surgery of a ventriculoperitoneal shunt. Intraoperatively, a blue coloration was observed in the catheter, a phenomenon previously described in urinary infections (1)(2) but not before in pathologies of the central nervous system. Our objective is to present an atypical case of dysfunction of the ventriculoperitoneal shunt, whose diagnosis couldbe evidenced through the coloration of the catheter exteriorized in surgery.


Asunto(s)
Derivación Ventriculoperitoneal , Humanos , Derivación Ventriculoperitoneal/efectos adversos , Masculino , Femenino , Hidrocefalia/cirugía
2.
Lett Appl Microbiol ; 75(1): 24-28, 2022 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-35285076

RESUMEN

Prototheca spp. cause numerous infections in a wide variety of species, including treatment-unresponsive mastitis. Thus, the search for an effective therapy is essential. Silver nanoparticles are compounds with high therapeutic potential. This study aimed to evaluate the susceptibility profile and morphological changes in Prototheca spp. treated with biogenic silver nanoparticles (Bio-AgNP). The algaecide activity was evaluated in microplates by microdilution method, resulting in a MIC50 of 30 µg ml-1 and a MIC90 of 60 µg ml-1 . Scanning electron microscopy demonstrated changes in the surface of Prototheca bovis cells following treatment. The algaecide activity of Bio-AgNP suggests a therapeutic potential as a novel approach for the control of Prototheca spp. in bovine mastitis.


Asunto(s)
Herbicidas , Mastitis Bovina , Nanopartículas del Metal , Prototheca , Animales , Bovinos , Femenino , Mastitis Bovina/tratamiento farmacológico , Plata/farmacología
3.
Eur Arch Paediatr Dent ; 22(6): 1067-1076, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34313973

RESUMEN

BACKGROUND/AIM: Dental trauma is a highly prevalent problem worldwide. The aim of this study was to describe characteristics of trauma to anterior primary teeth and its sequelae for primary and successor teeth over a 10-year period of assistance at the paediatric dental traumatology clinic in the State University of Rio de Janeiro, Brazil. MATERIALS AND METHODS: The data were obtained from the dental records of children assisted from 2006 to 2016. Inclusion criteria were trauma to anterior primary teeth; aged <1 to 9 years at the time of trauma; and at least one follow-up appointment. The data concerning traumatized teeth, child's age, soft tissue injuries, types of traumatic dental injuries and sequelae in both dentitions were collected. RESULTS: Of the 1230 dental records, 483 (39.3%) were eligible, consisting of 815 teeth. The mean age at the time of trauma was 37.4 months (239 males and 244 females). The most important characteristics were: tooth 51 was most affected; falls, at home, on a ceramic floor, were the main cause; gingival laceration, enamel fracture and intrusive luxation were the most frequent types of trauma; premature tooth loss of primary teeth and enamel discoloration in their successor were the most frequent sequelae; and injuries in the periodontal tissue were demonstrated as the highest risk for sequelae in successors (OR, 3.798; p< 0.001). CONCLUSIONS: Most traumatic injuries occur in young children, in their home environment. Consequences for the primary teeth were more frequent compared to the permanent successor tooth. Traumatized primary teeth involving periodontal tissue have more chances to result in sequelae to their successor teeth.


Asunto(s)
Avulsión de Diente , Traumatismos de los Dientes , Brasil/epidemiología , Niño , Preescolar , Dentición Permanente , Femenino , Humanos , Masculino , Estudios Retrospectivos , Avulsión de Diente/epidemiología , Traumatismos de los Dientes/epidemiología , Diente Primario
4.
Animal ; 14(12): 2588-2597, 2020 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-32669155

RESUMEN

There is a trend to reduce the space allowance per animal in cattle feedlot, despite its potential negative impact on animal welfare. Aiming to evaluate the effects of space allowance per animal in outdoor feedlots on beef cattle welfare, a total of 1350 Nellore bulls (450 pure and 900 crossbred) were confined for 12 weeks using three space allowances: 6 (SA6), 12 (SA12) and 24 (SA24) m2/animal (n = 450 per treatment). Bulls were housed in three pens per treatment (n = 150 per pen). The first 6 weeks in the feedlot were defined as 'dry' and the last as 'rainy' period, according to the accumulated precipitation. Animal-based (body cleanliness, health indicators and maintenance behaviour) and environmental-based indicators (mud depth and air dust concentration) were assessed weekly during the feedlot period. Most of the health indicators (nasal and ocular discharge, hoof and locomotion alterations, diarrhoea, bloated rumen and breathing difficulty) were assessed in a subset of 15 animals randomly selected from each pen. Coughs and sneezes were counted in each pen. Maintenance behaviours (number of animals lying and attending the feed bunk) were recorded with scan sampling and instantaneous recording at 20-min intervals. Postmortem assessments were carried out in all animals by recording the frequencies of macroscopic signs of bronchitis, pulmonary emphysema, nephritis and urinary cyst and by measuring the weight and cortical and medullar areas of adrenal glands (n = 30 per pen). Compared with SA12 and SA24, SA6 showed a greater number of sneezes per minute during the dry period and a greater percentage of animals with locomotion alterations during the rainy period. Coughing, diarrhoea and nasal discharge affected a larger number of animals in the SA6 relative to the other two groups. During the rainy period, there was a lower percentage of animals with nasal and ocular discharge, and a greater percentage of animals with abnormal hoof and lying. A lower percentage of animals in SA6 and SA12 (but not SA24) attended the feed bunk during the rainy relative to the dry period. A mud depth score of 0 (no mud) was most frequent in SA24 pens, followed by SA12 and then SA6. Adrenal gland weight and cortical area were lower in SA24 animals compared with those in SA6 and SA12. The results show that decreasing the space allowance for beef cattle in outdoor feedlots degrades the feedlot environment and impoverishes animal welfare.


Asunto(s)
Enfermedades de los Bovinos , Pezuñas y Garras , Alimentación Animal , Bienestar del Animal , Animales , Peso Corporal , Bovinos , Vivienda para Animales , Masculino
5.
World Neurosurg ; 138: e795-e805, 2020 06.
Artículo en Inglés | MEDLINE | ID: mdl-32217179

RESUMEN

OBJECTIVE: In this article, we describe a new safe entry point for the posterolateral pons. METHODS: To show the adjacent anatomy and measure the part of the interpeduncular sulcus that can be safely accessed, we first performed a review of the literature regarding the pons anatomy and its surgical approaches. Thereafter, 1 human cadaveric head and 15 (30 sides) human brainstems with attached cerebellums were bilaterally dissected with the fiber microdissection technique. A clinical correlation was made with an illustrative case of a dorsolateral pontine World Health Organization grade I astrocytoma. RESULTS: The safe distance for accessing the interpeduncular sulcus was found to extend from the caudal end of the lateral mesencephalic sulcus to the point at which the intrapontine segment of the trigeminal nerve crosses the interpeduncular sulcus. The mean distance was 8.2 mm (range, 7.15-8.85 mm). Our interpeduncular sulcus safe entry zone can be exposed through a paramedian infratentorial supracerebellar approach. When additional exposure is required, the superior portion of the quadrangular lobule of the cerebellar hemispheric tentorial surface can be removed. In the presented case, surgical resection of the tumor was performed achieving a gross total resection, and the patient was discharged without neurologic deficit. CONCLUSIONS: The interpeduncular sulcus safe entry zone provides an alternative direct route for treating intrinsic pathologic entities situated in the posterolateral tegmen of the pons between the superior and middle cerebellar peduncles. The surgical corridor provided by this entry point avoids most eloquent neural structures, thereby preventing surgical complications.


Asunto(s)
Microdisección/métodos , Microcirugia/métodos , Pedúnculo Cerebeloso Medio/cirugía , Procedimientos Neuroquirúrgicos/métodos , Puente/cirugía , Humanos , Pedúnculo Cerebeloso Medio/anatomía & histología , Puente/anatomía & histología
6.
Animal ; 14(4): 873-880, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-31650939

RESUMEN

The BW has been largely used as a selection criterion in genetic selection programmes; however, increases in BW can affect animal metabolism and metabolites. The knowledge of how genetic potential for growth affects the metabolites can give a footprint of growth metabolism. This research aimed to evaluate the effect of genetic potential for post-weaning growth (GG) on performance, carcass traits and serum metabolome of non-castrated Nellore males during the finishing phase. Forty-eight Nellore non-castrated males, with divergent potential for post-weaning growth, were selected and divided into two groups: high potential for post-weaning growth (HG; n = 24) and low potential for post-weaning growth (LG; n = 24). Animals were kept and fed for 90 days where performance and ultrasound carcass traits were evaluated. Blood samples were collected at the beginning and end of feeding period to analyse serum metabolites concentration. The hot carcass weight and dressing percentage were recorded at slaughter. The feedlot performance and carcass traits were not affected by genetic potential. The HG animals had a lower glucose (P = 0.039), glutamate (P = 0.038), glutamine (P = 0.004), greater betaine (P = 0.039) and pyruvate (P = 0.039) compared to the LG group at the beginning of feedlot. In addition, higher creatine phosphate concentrations were observed at the beginning of feeding period, compared to final, for both groups (P = 0.039). In conclusion, the genetic potential for post-weaning growth does not affect performance and carcass traits during the finishing period. Differences in metabolite concentrations can be better found at the beginning of feedlot, providing a footprint of growth metabolism, but similar metabolite concentration at the end of finishing period.


Asunto(s)
Bovinos/fisiología , Metabolómica , Carne Roja/análisis , Animales , Composición Corporal/genética , Bovinos/sangre , Bovinos/genética , Bovinos/crecimiento & desarrollo , Dieta/veterinaria , Masculino , Fenotipo , Destete
7.
Ecohealth ; 16(4): 743-758, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31712931

RESUMEN

In the Amazon and Orinoco basins, mercury has been released from artisanal and industrial gold mining since the Colonial time, as well as a result of deforestation and burning of primary forest, that release natural deposits of methyl mercury, affecting the local aquatic vertebrate fauna. This study reports the presence of mercury in river dolphins' genera Inia and Sotalia. Mercury concentrations were analysed in muscle tissue samples collected from 46 individuals at the Arauca and Orinoco Rivers (Colombia), the Amazon River (Colombia), a tributary of the Itenez River (Bolivia) and from the Tapajos River (Brazil). Ranges of total mercury (Hg) concentration in muscle tissue of the four different taxa sampled were: I. geoffrensis humboldtiana 0.003-3.99 mg kg-1 ww (n = 21, Me = 0.4), I. g. geoffrensis 0.1-2.6 mg kg-1 ww (n = 15, Me = 0.55), I. boliviensis 0.03-0.4 mg kg-1 ww (n = 8, Me = 0.1) and S. fluviatilis 0.1-0.87 mg kg-1 ww (n = 2, Me = 0.5). The highest Hg concentration in our study was obtained at the Orinoco basin, recorded from a juvenile male of I. g. humboldtiana (3.99 mg kg-1 ww). At the Amazon basin, higher concentrations of mercury were recorded in the Tapajos River (Brazil) from an adult male of I. g. geoffrensis (2.6 mg kg-1 ww) and the Amazon River from an adult female of S. fluviatilis (0.87 mg kg-1 ww). Our data support the presence of total Hg in river dolphins distributed across the evaluated basins, evidencing the role of these cetaceans as sentinel species and bioindicators of the presence of this heavy metal in natural aquatic environments.


Asunto(s)
Delfines , Monitoreo del Ambiente/métodos , Mercurio/análisis , Minería , Músculos/química , Ríos/química , Contaminantes Químicos del Agua/análisis , Animales , Brasil , Colombia , Conservación de los Recursos Naturales , Biomarcadores Ambientales
8.
J Phys Condens Matter ; 30(23): 235804, 2018 Jun 13.
Artículo en Inglés | MEDLINE | ID: mdl-29697405

RESUMEN

In this paper we studied the reversal magnetization of La1-x Sr x Fe0.5Cr0.5O3-δ (x = 0, 0.1 and 0.2) samples produced by combustion synthesis. The structural analysis was carried out by x-ray diffraction with Rietveld analysis. These analyses revealed that all samples have an orthorhombic structure with space group Pbnm (62) and that the Sr-doping induces a decrease of the lattice parameter. The x-ray photoelectron spectroscopy analysis indicates that the Sr-doping favor the change of the valence states of the Fe3+ to Fe4+. The magnetization as a function of the temperature reveals an unusual magnetic behavior with a reversal of magnetization. The increase of the Sr content induces a decrease of the temperature where occurs an inversion of the magnetization and do the value of the magnetization at 5 K more negative. This effect is attributed to the increase of the concentration of Fe4+ with increasing of the Sr content. The Fe and Cr with a valence of 4+ act as paramagnetic impurities in the antiferromagnetic lattice and are responsible for the changes in the magnetic behavior.

9.
Environ Technol ; 39(2): 231-239, 2018 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-28274191

RESUMEN

Development of highly active photocatalysts is mandatory for more widespread application of this alternative environmental technology. Synthesis of photocatalysts, such as anatase TiO2, with more reactive, non-equilibrium, crystallographic facets is theoretically justified by a more efficient interfacial charge transfer to reactive adsorbed species, increasing quantum efficiency of photocatalyst. Air and vacuum calcinations of protonated trititanate nanotubes lead to their transformation to anatase nanorods. The nanorods synthesized by air calcination demonstrate photo-oxidation of NO gas more than three times superior to the one presented by the benchmark P-25 photocatalyst. This performance has been explained in terms of 50% higher specific surface area and, more importantly, through the predominance of more reactive, non-equilibrium, {001} crystallographic facets of the anatase nanorods. These facets present a high density of undercoordinated Ti cations, which favors adsorption of reactant species, and strained Ti-O-Ti bonds, leading to more efficient photo-oxidation reactions. Reduced Ti species, such as Ti3+, were not observed in the as-obtained nanorods, while reactive adsorbed molecules are scarce on the nanorods obtained through vacuum calcination. Dip-coating of TiO2 anatase nanorods (air calcined) over soda-lime glass plates was used to prepare visible light transparent, superhydrophilic and highly adherent photocatalytic coatings with homogenously distributed nanopores.


Asunto(s)
Nanotubos/química , Óxido Nítrico/química , Procesos Fotoquímicos , Titanio/química , Oxidación-Reducción
10.
Sci Rep ; 7(1): 3242, 2017 06 12.
Artículo en Inglés | MEDLINE | ID: mdl-28607395

RESUMEN

The friction phenomenon is a ubiquitous manifestation of nature. Models considering phononic, electronic, magnetic, and electrostatic interactions are invoked to explain the fundamental forces involved in the friction phenomenon. In order to establish the incidence of the phonon prompting at the nanoscale friction by direct contact, we study a diamond spherical dome sliding on carbon thin films containing different amount of deuterium and hydrogen. The friction coefficient decreases by substituting hydrogen by deuterium atoms. This result is consistent with an energy dissipation vibration local mechanism from a disordered distribution of bond terminators.

11.
Lett Appl Microbiol ; 64(6): 419-423, 2017 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-28349671

RESUMEN

Prototheca species have increasingly been reported to be opportunistic pathogens that cause mastitis in dairy herds, and it poses an emergent problem because at present, there are no effective therapies for the treatment of protothecal mastitis. This study investigated the in vitro algicidal effect of guanidine on 75 Prototheca zopfii genotype 2 strains isolated from 75 cases of clinical and subclinical bovine mastitis. All strains were susceptible to guanidine in vitro with minimal algaecide concentrations ranging from 0·001 to 0·035%. Guanidine is known to have a high microbicidal effect and is considered to be a new generation microbicidal compound. It is not toxic to human mucous membranes and conjunctivas at low concentrations and has been used as a disinfectant in swimming pools and as an antiseptic for human wounds. The algicidal action of guanidine at low concentrations indicates that it could be an alternative disinfectant or antiseptic for cleaning of the dairy environment and milking equipment, in pre- and postdipping solutions, in the chemical dry therapy of bovine teats and even in the intramammary therapy of P. zopfii infections. This is the first report of the in vitro algicidal effect of guanidine on P. zopfii strains of animal origin. SIGNIFICANCE AND IMPACT OF THE STUDY: Prototheca zopfii genotype 2 is an opportunistic pathogen of bovine mastitis. To date, no effective therapies against protothecal mastitis have been developed. The in vitro algicidal effect of guanidine on 75 P. zopfii genotype 2 strains isolated from cows revealed that all of the isolates were susceptible to the compound at low concentrations, which indicates that guanidine may be used as an antiseptic/disinfectant for dairy milking equipment, in pre- and postdipping solutions, and as a chemical dry therapy or an intramammary therapy. This study describes the in vitro algicidal effect of guanidine on P. zopfii for the first time.


Asunto(s)
Guanidina/farmacología , Mastitis Bovina/epidemiología , Prototheca/efectos de los fármacos , Animales , Antiinfecciosos/farmacología , Antiinfecciosos Locales/farmacología , Bovinos , Industria Lechera , Desinfectantes/farmacología , Femenino , Genotipo , Humanos , Mastitis Bovina/tratamiento farmacológico , Epidemiología Molecular , Prototheca/genética , Prototheca/aislamiento & purificación
12.
J Anim Breed Genet ; 134(1): 27-33, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27905150

RESUMEN

The aim of this study was to estimate genetic parameters for prenatal (PRE) and postnatal (POS) mortality in Nellore cattle. A total of 13 141 (PRE) and 17 818 (POS) records from Nellore females were used. PRE and POS were recorded using binary scale scores: a score of '1' was given to calves that were born alive (PRE) and those that were alive at weaning (POS), and a score of '0' was given to calves that were not alive at or around birth (PRE), as well as to those weighed at birth but not at weaning (POS). The relationship matrix included 698 sires, 107 paternal grandsires and 69 maternal grandsires. Data were analysed using Bayesian inference and a sire-maternal grandsire threshold model, including contemporary groups as random effects, and the classes of dam age at the beginning of mating season (for PRE), and dam age at calving and birthweight (linear covariable) (for POS), as fixed effects. For both traits, the covariance between direct and maternal effects (rD,M ) was estimated (rD,M ≠ 0) or fixed at zero (rD,M  = 0). PRE and POS rates were 3.00 and 4.04%, respectively. Estimates of direct and maternal heritability were 0.07 and 0.17, respectively, for PRE, and 0.02 and 0.07, respectively, for POS, assuming rD,M  = 0. For rD,M  ≠ 0, these estimates were 0.07 and 0.12, respectively, for PRE, and 0.03 and 0.07, respectively, for POS. The correlation estimates between direct and maternal effects were -0.71 (PRE) and -0.33 (POS). PRE and POS show low genetic variability, indicating that these traits probably suffer major environmental influences. Additionally, our study shows that the maternal genetic component affects preweaning calf mortality twice as much (or more) as the direct genetic component. A large number of offspring per sire is necessary in progeny tests to genetically decrease calf mortality.


Asunto(s)
Bovinos/genética , Bovinos/fisiología , Animales , Animales Recién Nacidos , Bovinos/clasificación , Femenino , Mortalidad , Embarazo
14.
Skin Res Technol ; 22(3): 325-33, 2016 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-26346940

RESUMEN

BACKGROUND/PURPOSE: Ultraviolet (UV) radiation is responsible for sunburns, skin cancer, photoaging, and the production of reactive oxygen species (ROS). The awareness on preventing these deleterious effects made the use of anti-UVB formulations an important part of population habits; however, despite the availability of several antioxidants capable of ROS scavenging, the pharmaceutical market lacks products associating UV filters with natural compounds of proven efficacy. Here, we investigated the effect of rutin, a flavonoid with antioxidant activity, associated with UVB filters in dermocosmetic preparations. METHODS: Formulations were assessed through its antioxidant activity, in vitro photoprotective effectiveness, photostability, and in vivo skin tolerance (hydration, transepidermal water loss, and erythema). RESULTS: Samples containing rutin were compatible with the human skin and presented a pronounced antioxidant potential, with scavenging activity values 75% higher than the ones containing only UVB filters. Although rutin could not prevent the sunscreens photodegradation post-irradiation, the bioactive compound significantly increased the formulations critical wavelengths, showing a photoprotective gain, especially in the UVA range. CONCLUSION: In conclusion, the absorption in the UVA range, coupled with ROS scavenging potential, proved the positive effect of rutin applied to anti-UVB formulations, making this bioactive compound a promising candidate for photoprotection improvement.


Asunto(s)
Protectores contra Radiación/administración & dosificación , Rutina/administración & dosificación , Fenómenos Fisiológicos de la Piel/efectos de los fármacos , Fenómenos Fisiológicos de la Piel/efectos de la radiación , Protectores Solares/administración & dosificación , Rayos Ultravioleta/efectos adversos , Absorción de Radiación/efectos de los fármacos , Adulto , Antioxidantes/metabolismo , Relación Dosis-Respuesta a Droga , Relación Dosis-Respuesta en la Radiación , Sinergismo Farmacológico , Femenino , Filtración/métodos , Humanos , Piel/efectos de los fármacos , Piel/efectos de la radiación , Absorción Cutánea/efectos de los fármacos , Absorción Cutánea/fisiología , Absorción Cutánea/efectos de la radiación , Pérdida Insensible de Agua/efectos de los fármacos , Pérdida Insensible de Agua/fisiología , Pérdida Insensible de Agua/efectos de la radiación
15.
Curr Microbiol ; 71(4): 476-82, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-26092419

RESUMEN

The photoprotective and antimutagenic activity of opened and closed basidiocarps of Agaricus subrufescens (=A. blazei; =A. brasiliensis) obtained by different extraction methods were evaluated on Aspergillus nidulans conidia submitted to ultraviolet (UV) light. The aqueous extracts were obtained by three extraction methods: maceration, infusion, and decoction, at two different extraction times. The extracts of A. subrufescens did not present toxicity for A. nidulans conidia. A suspension of A. nidulans conidia was submitted to extracts before and after the exposure to UV light. All basidiocarp extracts, regardless of the extraction method or development stage, protected A. nidulans conidia against the damaging effects of the mutagenic agent. The antimutagenic and photoprotective activity was strengthened with extracts obtained by 168-h maceration, followed by 24-h maceration and 60-min infusion and, at last, by 30-min infusion. Although the extracts presented protector effect as well as recoverer effect to the action of UV light, the preventive effect was more evident. Differences in the biological activity in function of the different development stages were detected with greater antimutagenic and photoprotective activity for the opened basidiocarps. However, the extraction method is the most important factor to be considered when compared to the basidiocarp development stage to obtain better antimutagenic and photoprotective activity of A. subrufescens basidiocarps.


Asunto(s)
Agaricus/química , Antimutagênicos/aislamiento & purificación , Aspergillus nidulans/efectos de los fármacos , Aspergillus nidulans/efectos de la radiación , Viabilidad Microbiana/efectos de los fármacos , Viabilidad Microbiana/efectos de la radiación , Protectores contra Radiación/aislamiento & purificación , Antimutagênicos/metabolismo , Cuerpos Fructíferos de los Hongos/química , Protectores contra Radiación/metabolismo , Esporas Fúngicas/efectos de los fármacos , Esporas Fúngicas/efectos de la radiación
16.
Nature ; 519(7541): 78-82, 2015 Mar 05.
Artículo en Inglés | MEDLINE | ID: mdl-25739631

RESUMEN

In 2005 and 2010 the Amazon basin experienced two strong droughts, driven by shifts in the tropical hydrological regime possibly associated with global climate change, as predicted by some global models. Tree mortality increased after the 2005 drought, and regional atmospheric inversion modelling showed basin-wide decreases in CO2 uptake in 2010 compared with 2011 (ref. 5). But the response of tropical forest carbon cycling to these droughts is not fully understood and there has been no detailed multi-site investigation in situ. Here we use several years of data from a network of thirteen 1-ha forest plots spread throughout South America, where each component of net primary production (NPP), autotrophic respiration and heterotrophic respiration is measured separately, to develop a better mechanistic understanding of the impact of the 2010 drought on the Amazon forest. We find that total NPP remained constant throughout the drought. However, towards the end of the drought, autotrophic respiration, especially in roots and stems, declined significantly compared with measurements in 2009 made in the absence of drought, with extended decreases in autotrophic respiration in the three driest plots. In the year after the drought, total NPP remained constant but the allocation of carbon shifted towards canopy NPP and away from fine-root NPP. Both leaf-level and plot-level measurements indicate that severe drought suppresses photosynthesis. Scaling these measurements to the entire Amazon basin with rainfall data, we estimate that drought suppressed Amazon-wide photosynthesis in 2010 by 0.38 petagrams of carbon (0.23-0.53 petagrams of carbon). Overall, we find that during this drought, instead of reducing total NPP, trees prioritized growth by reducing autotrophic respiration that was unrelated to growth. This suggests that trees decrease investment in tissue maintenance and defence, in line with eco-evolutionary theories that trees are competitively disadvantaged in the absence of growth. We propose that weakened maintenance and defence investment may, in turn, cause the increase in post-drought tree mortality observed at our plots.


Asunto(s)
Carbono/metabolismo , Sequías , Bosques , Clima Tropical , Brasil , Dióxido de Carbono/metabolismo , Respiración de la Célula , Fotosíntesis , Árboles/citología , Árboles/metabolismo
17.
J Anim Breed Genet ; 132(1): 42-50, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25174988

RESUMEN

The aim of this study was to estimate genetic associations between temperament and performance traits. Temperament was evaluated in yearling male and female Nellore cattle, using four traits: temperament score (TS), for assessing animals' reactions in a corral pen (n = 25,691); movement score (MOV), for animals' movements recorded inside the crush; crush score (CS), for animal's general reactivity inside the crush; and flight speed (FS), for the speed (in m/s) at which the animals exited the crush (n = 11,697, for the last three methods); for all the temperament traits, lower scores indicate animals with calmer temperament. Performance traits were visual scores for conformation (C), finishing precocity (P) and muscling (M) evaluated at yearlings, and average daily gain (ADG) was estimated from weaning to yearling. Bayesian inference using Gibbs sampling was applied to estimate (co)variance components and genetic and phenotypic parameters. Heritability estimates for the temperament traits ranged from 0.07 (CS) to 0.28 (FS). Genetic correlations of the temperament traits with ADG and C, P and M were negative and ranged from -0.02 to -0.31. Phenotypic correlations were negative and consistently lower than the genetic, ranging from -0.08 to -0.02. It was concluded that the temperament traits assessed had favourable genetic correlation estimates with the performance traits studied. However, indirect responses in temperament when selecting for higher ADG and visual scoring system of C, P and M, will be low.


Asunto(s)
Bovinos/genética , Estudios de Asociación Genética , Temperamento , Animales , Teorema de Bayes , Bovinos/crecimiento & desarrollo , Bovinos/fisiología , Femenino , Genotipo , Masculino , Fenotipo
18.
Animal ; 9(2): 313-9, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25252882

RESUMEN

In vitro preservation of the male gamete is a challenge in the development of artificial insemination techniques for domestic animals. Specific strategies and diluents have been developed for the preservation of the fertilizing ability of the semen for each species. However, the epididymal medium has been demonstrated to be the best sperm environment to maintain sperm viability over several days and weeks for mammals. The aims of this study were to evaluate the motility and in vivo fertility of ram epididymal spermatozoa when the semen was stored for up to 4 days at 4°C undiluted in epididymal plasma. The study was undertaken with two ovine breeds (Ile de France and Corriedale). The motility of epididymal spermatozoa was better preserved in the undiluted epididymal fluid than when epididymal spermatozoa were diluted in classic ovine extender such as skim milk. During storage, the decrease in the percentage of motile sperm was lower if the epididymal spermatozoa were collected immediately after epididymal sampling than 24 h after castration or animal death. The fertility obtained after cryopreservation of the stored sperm and subsequent intrauterine insemination ranged from 55% to 24% following 24 to 96-h sperm storage. There was a linear regression relationship between fertility and the number of motile sperm inseminated for both breeds. These results show that it is possible to keep epididymal sperm motile and fertile for several days without dilution. Such a method of sperm preservation could be a final possibility for animals of high genetic value or for endangered species when the collection of semen before death of the animal is not possible.


Asunto(s)
Criopreservación/veterinaria , Fertilidad , Preservación de Semen/veterinaria , Ovinos/fisiología , Espermatozoides/fisiología , Animales , Criopreservación/métodos , Epidídimo/fisiología , Fertilización In Vitro/veterinaria , Inseminación Artificial , Modelos Lineales , Masculino , Semen/fisiología , Análisis de Semen/veterinaria , Preservación de Semen/métodos , Oveja Doméstica
19.
Mater Sci Eng C Mater Biol Appl ; 43: 45-9, 2014 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25175186

RESUMEN

Low modulus of elasticity and the presence of non-toxic elements are important criteria for the development of materials for implant applications. Low modulus Ti alloys can be developed by designing ß-Ti alloys containing non-toxic alloying elements such as Nb and Zr. Actually, most of the metallic implants are produced with stainless steel (SS) because it has adequate bulk properties to be used as biomaterials for orthopedic or dental implants and is less expensive than Ti and its alloys, but it is less biocompatible than them. The coating of this SS implants with Ti alloy thin films may be one alternative to improve the biomaterial properties at a relatively low cost. Sputtering is a physical deposition technique that allows the formation of nanostructured thin films. Nanostructured surfaces are interesting when it comes to the bone/implant interface due to the fact that both the surface and the bone have nanoscale particle sizes and similar mechanical properties. TiNbZr thin films were deposited on both Si(111) and stainless steel (SS) substrates. The TiNbZr/Si(111) film was used as a model system, while the TiNbZr/SS film might improve the biocompatibility and extend the life time of stainless steel implants. The morphology, chemical composition, Young's modulus, and hardness of the films were analyzed by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), and nanoindentation.


Asunto(s)
Propiedades de Superficie , Titanio , Materiales Biocompatibles , Microscopía de Fuerza Atómica , Nanotecnología , Espectroscopía de Fotoelectrones , Espectrometría por Rayos X
20.
Transplant Proc ; 45(5): 1715-9, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23769030

RESUMEN

BACKGROUND: Damage provoked by ischemia in renal transplants is difficult to quantify. To determine whether a donated organ is fit for transplantation. We sought to correlate the findings of fluorescence spectroscopy (FS) with histologic evidence of ischemic injury and organ viability. METHODS: Kidneys of 33 rats were submitted to FS of the upper and lower poles as well as the middle third. Excitation was generated by the laser's wavelengths of 408, 442, and 532 nm. Rats were randomized into groups with the 30, 60, and 120 minutes warm ischemia before analysis by FS, that was repeated at 5 minutes after reperfusion. RESULTS: FS results in the reperfusion phase correlated with ischemia time and degree of histologic injury. After 60 or 120 minutes of ischemia, the excitation lasers of 532 and 442 nm resented a significant negative correlation coefficient with the histological grade (r = -0.61 and r = -0.73, respectively). CONCLUSIONS: There was a strong correlation between FS and histologic changes only in the reperfusion phase after renal ischemia. The method was thus unable to assess the viability of organs before transplantation.


Asunto(s)
Riñón/irrigación sanguínea , Daño por Reperfusión/diagnóstico , Espectrometría de Fluorescencia/métodos , Animales , Masculino , Ratas , Ratas Wistar
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