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"Parra, H."
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The 2010 Mw 8.8 Maule Megathrust Earthquake of Central Chile, Monitored by GPS
2011
Large earthquakes produce crustal deformation that can be quantified by geodetic measurements, allowing for the determination of the slip distribution on the fault. We used data from Global Positioning System (GPS) networks in Central Chile to infer the static deformation and the kinematics of the 2010 moment magnitude (M(w)) 8.8 Maule megathrust earthquake. From elastic modeling, we found a total rupture length of ~500 kilometers where slip (up to 15 meters) concentrated on two main asperities situated on both sides of the epicenter. We found that rupture reached shallow depths, probably extending up to the trench. Resolvable afterslip occurred in regions of low coseismic slip. The low-frequency hypocenter is relocated 40 kilometers southwest of initial estimates. Rupture propagated bilaterally at about 3.1 kilometers per second, with possible but not fully resolved velocity variations.
Journal Article
Phase II study of pemetrexed and carboplatin plus bevacizumab as first-line therapy in malignant pleural mesothelioma
2013
Background:
The aim of this open label phase II study (NCT00407459) was to assess the activity of the vascular endothelial growth factor (VEGF) inhibitor bevacizumab combined with pemetrexed and carboplatin in patients with previously untreated, unresectable malignant pleural mesothelioma (MPM).
Methods:
Eligible patients received pemetrexed 500 mg m
−2
, carboplatin area under the plasma concentration–time curve (AUC) 5 mg ml
−1
per minute and bevacizumab 15 mg kg
−1
, administered intravenously every 21 days for six cycles, followed by maintenance bevacizumab. The primary end point of the study was progression-free survival (PFS). A 50% improvement in median PFS in comparison with standard pemetrexed/platinum combinations (from 6 to 9 months) was postulated.
Results:
Seventy-six patients were evaluable for analysis. A partial response was achieved in 26 cases (34.2%, 95% CI 23.7–46.0%). Forty-four (57.9%, 95% CI 46.0–69.1%) had stable disease. Median PFS and overall survival were 6.9 and 15.3 months, respectively. Haematological and non-haematological toxicities were generally mild; however, some severe adverse events were reported, including grade 3–4 fatigue in 8% and bowel perforation in 4% of patients. Three toxic deaths occurred.
Conclusion:
The primary end point of the trial was not reached. However, due to the limitation of a non-randomised phase II design, further data are needed before drawing any definite conclusion on the role of bevacizumab in MPM.
Journal Article
Analysis of epidermal growth factor receptor expression as a predictive factor for response to gefitinib (‘Iressa’, ZD1839) in non-small-cell lung cancer
by
Campagnoli, E
,
Roncalli, M
,
Santoro, A
in
Adenocarcinoma - drug therapy
,
Adenocarcinoma - metabolism
,
Adult
2004
Gefitinib (‘Iressa’, ZD1839) is an orally active epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has demonstrated antitumour activity and favourable tolerability in Phase II studies. We investigated whether EGFR expression levels could predict for response to gefitinib in patients with advanced non-small-cell lung cancer (NSCLC), who received gefitinib (250 mg day
−1
) as part of a worldwide compassionate-use programme. Tissue samples were analysed by immunohistochemistry to assess membrane EGFR immunoreactivity. Of 147 patients enrolled in our institution, 50 patients were evaluable for assessment of both clinical response and EGFR expression. The objective tumour response rate was 10% and disease control was achieved in 50% of patients. Although high EGFR expression was more common in squamous-cell carcinomas than adenocarcinomas, all objective responses were observed in patients with adenocarcinoma. Response and disease control with gefitinib were not associated with high EGFR expression. Overall, median survival was 4 months, and the 1-year survival rate was 18%. Strong EGFR staining correlated with shorter survival time for all patients. Gefitinib demonstrated promising clinical activity in this group of patients with NSCLC. These results have also shown that EGFR expression is not a significant predictive factor for response to gefitinib.
Journal Article
Environmental factors that modulate the release and transport of airborne urediniospores Hemileia vastatrix (Berk. & Broome) in coffee crops in Veracruz México
by
Martínez-López, B.
,
Calderón-Ezquerro, M. C.
,
Guerrero-Parra, H. A.
in
Air transportation
,
Allergology
,
canopy
2022
The coffee leaf rust,
Hemileia vastatrix
, is the most destructive coffee-growing disease and the most important economically. More aggressive outbreaks of the disease were recently reported worldwide, including in Mexico, where coffee production showed a 40% decrease. This work aimed to determine the environmental conditions that favor release and air transport of the
H. vastatrix
urediniospores in coffee crops in Veracruz. The monitoring of airborne coffee leaf rust urediniospores was performed using three types of aerobiological traps at different heights: Hirst Spore Trap (HST, 1.5 m), Passive Spore Trap (PST 1.5, 3, 6, and 9 m), and Sedimentation Spore Sampler (SSS 1 m) from January 2014 to October 2015, in two plots in Veracruz, Mexico. The airborne urediniospores counts exhibited a bimodal distribution. Low concentrations that increase over time are evident from January to April, decreasing abruptly in May and June, only to rise again in August, reaching the highest record for airborne urediniospores during the mid-summer drought phenomenon. Dispersal of coffee rust urediniospores is mainly influenced by temperature, rain, wind, and humidity in leaves. They can reach heights in the air up to 9 m (above the canopy) in shade coffee crops. The dispersal of pathogens in the atmosphere comprises complex processes interconnected; their knowledge allows better comprehensive management of them.
Journal Article
Detection, Quantification and Molecular Characterization of Fowl Adenoviruses Circulating in Ecuadorian Chicken Flocks during 2019–2021
2023
Fowl adenoviruses are a group of pathogens that cause large economic losses worldwide in the poultry industry, in addition to producing a wide range of diseases, such as IBH, HHS, and enteric and respiratory diseases. The objective of this study was to quantify, identify, and molecularly characterize the types of FAdV circulating in commercial poultry farms (broilers, breeders, and layers) in Ecuador from 2019 to 2021. Molecular characterization was performed by PCR, quantification by qPCR, and subsequent sequencing for each positive sample. The results indicated that the FAdV genotypes circulating in our country are FAdV-2/D2, FAdV-6/E1, FAdV-8a/E2, and FAdV-11/D3; the samples were grouped into different groups that contain sequences that were obtained from countries in Africa, Asia, and America, and that are found in birds at different ages, since early age where can cause different clinical signs, such as diarrhea, ruffled feathers and dwarfism. Therefore, these results indicate that several genotypes of the virus are circulating in commercial poultry flocks, suggesting that biosecurity measures on farms should be improved, in addition to carrying out new or improved vaccination plans.
Journal Article
Detection of Avian Bornavirus in Wild and Captive Passeriformes in Brazil
by
Nuñez, Luis F.
,
Astolfi-Ferreira, Claudete S.
,
Ferreira, Antonio J. Piantino
in
Animals
,
Animals, Wild
,
Animals, Zoo
2019
Avian bornaviruses (ABVs) are the causative agents of proventricular dilatation disease (PDD), a fatal neurologic disease considered to be a major threat to psittacine bird populations. We performed a reverse transcription PCR survey to detect the presence of canary avian bornavirus (CnBV) in birds of order Passeriformes related to different clinical manifestations, such as sudden death, neurologic signs, apathy, anorexia, excessive beak growth, and PDD. A total of 227 samples from captive and wild canaries were included, of which 80 samples were captive birds, comprising saffron finches (n = 71) and common canary (n = 9), and 147 samples were wild birds distributed among a variety of several species. Two samples from captive birds (2/80) were positive for ABV, and in wild birds, only one sample was positive for ABV. The positive samples were subjected to DNA sequencing, and only the CnBV-1 serotype was found, which was the first time it was detected outside of Germany (Austria/Hungary), where it was first detected in 2009. Phylogenetic analysis confirmed that avian bornavirus serotype CnBV-1 is present in order Passeriformes in Brazil.
Journal Article
Juveniles and where to find them: a basin-scale habitat model for the lost years of loggerhead sea turtles in the North Atlantic
2026
Background
Juvenile loggerhead sea turtles represent a crucial but understudied stage of the species life cycle. Most studies have been conducted at regional scales and there remains a need for a broader scale synthesis. In the North Atlantic, loggerheads encounter numerous threats such as fishing during their transoceanic journey, so it is important to get a broad view of their distribution, movement and habitat preferences.
Methods
For this study, we gathered tracking data from 124 juvenile loggerheads tagged along the Azores, Canary Islands, Madeira and in the western North Atlantic to develop a habitat model for the entire basin. We used a SSM to interpolate tracks to daily positions, simulated pseudo-absences with a correlated random walk for background data, and explored 17 environmental variables using boosted regression trees to select the best model in terms of biological realism and predictive power. The best model obtained (AUC = 0.988) was then used to predict habitat suitability for the North Atlantic for the period 1998–2022. Stranding records of loggerheads in France, UK and Ireland were used to discuss the predictions.
Results
After filtering, tracks of 105 individuals, covering most of the basin, were used in the model. Our predictions of habitat suitability show the importance of the Gulf Stream and the Azorean Current. Habitat suitability is predicted to be higher in the area between 30° and 45°N all year round, while open waters below 30°N, including Cape Verde, are not predicted to be a suitable habitat. In northern and eastern areas, like the Bay of Biscay and UK and Irish waters, habitat suitability varied seasonally, with colder seasons showing lower values. Accordingly, strandings in those areas occurred mostly during winter (December-February; 45.1%) and spring (March-May; 34.1%).
Conclusions
The model offers a first basin-scale prediction of the seasonal distribution of juvenile loggerheads in the North-Atlantic, which shows consistency with stranding and bycatch data in the basin. This study represents a first step towards a broader scale understanding of juveniles’ habitat preferences that can be used to quantify the magnitude and extent of the threats that they face.
Journal Article
Optimization of the mechanical behavior of ABS and PLA 3D printed using heat treatments
by
Escobar-Barrios, Vladimir
,
Tapia, Fidencio
,
Rodríguez-Reyna, S. L.
in
3-D printers
,
Acrylonitrile butadiene styrene
,
Applied and Technical Physics
2025
This research evaluated the ultimate tensile strength (UTS), hardness and crystallinity of 3D printed parts with and without heat treatments (HT). For acrylonitrile butadiene styrene (ABS), temperatures of 70, 80 and 90 °C were applied for 10, 20 and 30 min, and for PLA, 75, 90 and 105 °C were applied for 20, 40 and 60 min. The experimental design included two factors: percentage of infill (33%, 66% and 100%) and geometric pattern (linear, triangular and hexagonal), with three levels of measurement for each factor. UTS increased with higher infill percentage, reaching 35.5 MPa for ABS and 46.5 MPa for PLA with hexagonal pattern. Optimal HTs raised UTS to 49 MPa for ABS (70 °C, 10 min) and 64 MPa for PLA (75 °C, 20 min), matching or exceeding the properties of the original filament. In addition, hardness and crystallinity improved, reducing internal voids and strengthening mechanical properties. Thus, the methodology presented in this work joining Design of Experiments and HT contributes to pieces with a better mechanical performance.
Graphical Abstract
Optimization of ABS and PLA printed parts via heat treatments
Journal Article
Study on the ultimate tensile stress and fatigue life in recycled PLA printed by FDM with different percentages of relative humidity
by
Tapia, Fidencio
,
Rodríguez-Reyna, S. L.
,
Acevedo-Parra, H. R.
in
Contours
,
Design of experiments
,
Fatigue life
2025
Effect of relative humidity in Fused Deposition Modeling specimens on tensile and fatigue mechanical properties is evaluated. Virgin and recycled PLA specimens are generated using a factorial DoE study with three factors: Relative humidity (three levels 18%, 22%, and 26%); number of perimeters (two levels: 3 and 6 contours); and nozzle temperature (two levels: 190 °C and 220 °C). UTS is output factor of ANOVA. Virgin and recycled PLA specimens with the highest UTS values were fatigue tested under cyclic tensile loading, with stress increments from 50 to 90% UTS in 10% increments. The objective is to determine the number of cycles to failure. Results show that virgin PLA achieves higher UTS values than recycled PLA. The combination of recycled PLA with 18%HR, six contours, and a nozzle temperature of 190 °C achieves a UTS of 29 MPa, higher than its own filament of 18 MPa and more than 100 × 103cycles to fatigue.
Journal Article
Emergence of Enteric Viruses in Production Chickens Is a Concern for Avian Health
by
Ferreira, Antônio José Piantino
,
Jerez, José A.
,
Mettifogo, Elena
in
Adenovirus
,
Animals
,
Astrovirus
2014
Several viruses have been identified in recent years in the intestinal contents of chickens and turkeys with enteric problems, which have been observed in commercial farms worldwide, including Brazil. Molecular detection of these viruses in Brazil can transform to a big threat for poultry production due to risk for intestinal integrity. This disease is characterized by severely delayed growth, low uniformity, lethargy, watery diarrhea, delayed feed consumption, and a decreased conversion rate. Chicken astrovirus (CAstV), rotavirus, reovirus, chicken parvovirus (ChPV), fowl adenovirus of subgroup I (FAdV-1), and avian nephritis virus (ANV) were investigated using the conventional polymerase chain reaction (PCR) and the reverse transcription polymerase chain reaction (RT-PCR). In addition, the infectious bronchitis virus (IBV), which may play a role in enteric disease, was included. The viruses most frequently detected, either alone or in concomitance with other viruses, were IBV, ANV, rotavirus, and CAstV followed by parvovirus, reovirus, and adenovirus. This study demonstrates the diversity of viruses in Brazilian chicken flocks presenting enteric problems characterized by diarrhea, growth retard, loss weight, and mortality, which reflects the multicausal etiology of this disease.
Journal Article