503 research outputs found
A modified technique of orthotopic transplant of the kidney in rabbits
In this study kidneys were harvested from bred-for-research cats weighing 4 to 5 kg. General principles of donor bilateral nephrectomy en bloc with aorta, vena cava, renal vessels, and ureters were followed. After the harvest the grafts were placed in lactated Ringer slush. A cuff was prepared on the renal vein over a 10 French plastic tube. The aorta was divided and left in connection with the renal artery at each side. Twenty female checkered Flemish giant rabbits weighing 4.0-6.0 kg served as recipients. After premedication with 40 mg/kg of ketamine, anesthesia was maintained with repeated doses (every 10-15 min) of a 0.1-mL mixture of 5 parts ketamine and 1 part acepromazine diluted 50% in a normal saline. Arterial pressure, CVP, blood gases, and temperature were monitored. Through a limited midline incision a native left nephrectomy was performed. The venous anastomosis was performed with a cuff technique without clamping the vena cava (which causes severe hemodynamic instability); the anastomotic time was 2-3 min. The arterial anastomosis was performed with an end-to-side aorta-to-aorta anastomosis; the anastomotic time was 5 to 7 min. There were no episodes of venous or arterial thrombosis. The donor procedure took approximately 40 min, and the backtable preparation of the graft an additional 45 to 60 min. Preparation of the recipient for the anastomosis took 15 min and the anastomotic time (warm ischemia) was 13 +/- 5 min. In this model suitable for xenograft research the duration of the surgery in the recipient has been greatly reduced because of (1) the previous backtable preparation of the graft, and (2) the cuff technique used for venous anastomosis. The present anesthesia regimen and careful hemodynamic monitoring were also important in the success of this model
Functionally graded plate fracture analysis using the field boundary element method
This paper describes the Field Boundary Element Method (FBEM) applied to the fracture analysis of a 2D rectangular plate made of Functionally Graded Material (FGM) to calculate Mode I Stress Intensity Factor (SIF). The case study of this Field Boundary Element Method is the transversely isotropic plane plate. Its material presents an exponential variation of the elasticity tensor depending on a scalar function of position, i.e., the elastic tensor results from multiplying a scalar function by a constant taken as a reference. Several examples using a parametric representation of the structural response show the suitability of the method that constitutes a Stress Intensity Factor evaluation of Functionally Graded Materials plane plates even in the case of more complex geometries
Failure analysis of fiberglass cover used for photovoltaic plants
Cover boxes with inspection glass are generally used outdoors for photovoltaic systems.Sometimes these boxes break, during normal use. Hightemperature, thermal stress, cyclic stress, and cracking contribute to weakening the polymeric inspection “glass”. The study presents an interdisciplinary analysis to discover the mode of occurrence and causes of the failure. First, the material is accurately characterized. Then its mechanical behavior is characterized in a virtual scenario that reconstructs the real external environment. The goal is to build a new cover with inspection boxes that exhibits superior life cycle behavior when exposed to harsh weather conditions and atmospheric agents. The breaking phenomena of solar panels covering boxes in PMMA (Poly Methyl Methacrylate) are examined. Environmental stress is the main responsible for cracking. Styrene is employed in the polymerization process of Sheet Molding Compound (SMC); the diffusion of this material is the main responsible for cracking. Comprehensive engineering analysis shows how the thermoplastic component fails after being exposed to atmospheric agents. The PMMA “glass” is one of the polymers most sensible to the crazing phenomena
Registro de Tetranychus mexicanus (McGregor) (Acari: Tetranychidae) em mamoeiro (Carica papaya L.) no estado do Acre, Brasil.
Resumo. Foi efetuado o primeiro registro do ácaro Tetranychus mexicanus (McGregor) em mamoeiro no MunicĂpio de Rio Branco, Acre. Foi detectada a presença de teia, perda de área fotossintetizante, necrose e secamento das folhas das plantas infestadas. Este Ă© o primeiro registro dessa espĂ©cie de ácaro no estado do Acre. Abstract. The occurrence of the spider mite Tetranychus mexicanus (McGregor) in papaya plants was reported in the municipality of Rio Branco, Acre state, Brazil. The leaves of the infested plants presented web, loss of photosynthesizing area, necrosis and drying. This is the first record of this species of mite in the Acre State
Alteration effects of volcanic ash in seawater: Anomalous Y/Ho ratios in coastal waters of the Central Mediterranean sea
This paper presents the results of a study based on data collected during the oceanographic cruise ANSIC 2001 carried out in the Ionian Sea during the explosive activity of Mount Etna in the summer of 2001. Anomalous low values of Y/Ho ratios in seawater suggest extensive scavenging processes on the surfaces of smectitic alteration products, with Y and Ho fractionation controlled by the differences in their electronic configurations and behaviour during solution/surface complexation equilibria. These processes can also be traced through the presence of significant tetrad effects recorded in the chondrite-normalised Rare Earth Elements and Yttrium (YREEs) patterns of suspended particulate matter. This suggests that the preferential Y scavenging from seawater is due to the formation of inner-sphere complexes with OH- groups on montmorillonite crystal surfaces. The preliminary results of kinetic experiments of YREE released from volcanic ash to coexisting seawater, and the related effects on Y/Ho ratios and Ce anomalies, are consistent with the fractionation of Light Rare Earth Elements (LREEs) with respect to Heavy Rare Earth Elements (HREEs) observed in dissolved phase. They suggest a behaviour of Y similar to that reported for LREEs, particularly for Ce and Pr. © 2007 Elsevier Ltd. All rights reserved
Expression of angiogenic regulators, VEGF and leptin, is regulated by the EGF/PI3K/STAT3 pathway in colorectal cancer cells.
Abstract
Both leptin and vascular endothelial growth factor (VEGF) are growth and angiogenic cytokines that are upregulated in different types of cancer and have been implicated in neoplastic progression. Here we investigated the molecular mechanism by which leptin and VEGF expression are regulated in colon cancer by epidermal growth factor (EGF). In colon cancer cell line HT-29, EGF induced the binding of signal transducer and activator transcription 3 (STAT3) to STAT3 consensus motifs within the VEGF and leptin promoters and stimulated leptin and VEGF mRNA and protein synthesis. All these EGF effects were significantly blocked when HT-29 cells were treated with an inhibitor of the phosphoinositide 3-kinase (PI3K) pathway, LY294002, or with small interfering RNA (siRNA) targeting STAT3. Thus, our study identified the EGF/PI3K/STAT3 signaling as an essential pathway regulating VEGF and leptin expression in EGF-responsive colon cancer cells. This suggests that STAT3 pathways might constitute attractive pharmaceutical targets in colon cancer patients where anti-EGF receptor drugs are ineffective
Prokaryotic abundance and heterotrophic metabolism in the deep Mediterranean Sea
A synthesis of field data carried out in the Mediterranean Sea are presented, aimed at contributing to the knowledge of three prokaryotic-mediated processes and their implications on the Carbon cycle. The distribution of exoenzymatic activities, secondary production and respiration rates was studied together with the prokaryotic abundances. Particular attention was paid to the meso- and bathypelagic layers which play an important role in the Mediterranean carbon cycle. The study is noteworthy because of its large spatial scale spanning the entire Mediterranean Sea over 4 years. In addition, two Atlantic stations in front of the Gibraltar Strait were investigated. The longitudinal distribution of prokaryotic activities and abundance along the MED showed different trends along the depthlayers. In particular, higher exoenzymatic rates were detected in the Eastern basin compared to the Western one; carbon respiration rate showed patterns variable with the sampling periods in the epipelagic and bathypelagic layers, while a consistent Westwards decreasing trend at the mesopelagic layers occurred. Specific enzyme activities per cell showed high values in the deepest layers for leucine aminopeptidase. Comparison with Carbon respiration rate data collected before the 2000s showed changing patterns of microbial heterotrophic processes in the Mediterranean Sea
A new species of Armascirus and description of the male of Scutopalus tomentosus from Brazil (Acari: Cunaxidae).
In this work, we describe the male of Scutopalus tomentosus Rocha, Skvarla & Ferla, 2013 and a new speciesArmascirus amazoniensis Wurlitzer & Silvasp. nov. from specimens collected on coconut crop, Cocos nuciferaL. (Arecaceae), cultivated in state of Pará, into the Amazonic biome, Brazil
Azithromycin SR versus minocycline in the treatment of moderate to severe acne: a phase III, multicentre, randomized, non-inferiority trial
Introduction: The primary objective of this phase III, multicentre, randomized trial was to evaluate whether azithromycin SR (azithromycin microspheres, powder for oral suspension) was non-inferior to oral minocycline in the treatment of moderate to severe acne. The primary efficacy
endpoint was the change from baseline in the GAGS score. Secondary endpoints included changes from baseline in the Leeds score and quality of life (QoL).
Methods: A total of 118 patients were randomized (1:1) to receive azithromycin SR (2 g/week) (n = 58) or minocycline (100 mg q.d.) (n = 60) for eight weeks.
Results: The change from baseline to end of treatment in GAGS score did not differ significantly between the azithromycin SR and minocycline groups [least squares mean -8.69 (95% confidence interval [CI]: -10.33 to -7.05) and -9.16 (95% CI: -10.62 to -7.71), respectively], consistent with the noninferiority of azithromycin SR to minocycline. The lower limit of 95% confidence interval of the change from baseline to end of treatment in GAGS scores
between the 2 groups (95% CI: -2.48 to 1.54) did not exceed the pre-defined non-inferiority margin of -3. In addition, there were no significant differences in improvement of acne graded by the Leeds score and QoL. Twenty-six patients (44.8%) in the azithromycin SR group and 9 patients (15%) in the minocycline group reported gastro-intestinal disorders.
Conclusions: In patients with moderate to severe acne, azithromycin SR is non-inferior to minocycline for primary endpoint (GAGS score), with no significant differences in secondary endpoints
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