513 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
Intertwining ROP Gadgets and Opaque Predicates for Robust Obfuscation
Software obfuscation plays a crucial role in protecting intellectual property in software from reverse engineering attempts. While some obfuscation techniques originate from the obfuscation-reverse engineering arms race, others stem from different research areas, such as binary software exploitation.
Return-oriented programming (ROP) gained popularity as one of the most effective exploitation techniques for memory error vulnerabilities. ROP interferes with our natural perception of a process control flow, which naturally inspires us to repurpose ROP as a robust and effective form of software obfuscation. Although previous work already explores ROP's effectiveness as an obfuscation technique, evolving reverse engineering research raises the need for principled reasoning to understand the strengths and limitations of ROP-based mechanisms against man-at-the-end (MATE) attacks.
To this end, we propose ROPFuscator, a fine-grained obfuscation framework for C/C++ programs using ROP. We incorporate opaque predicates and constants and a novel instruction hiding technique to withstand sophisticated MATE attacks. More importantly, we introduce a realistic and unified threat model to thoroughly evaluate ROPFuscator and provide principled reasoning on ROP-based obfuscation techniques that answer to code coverage, incurred overhead, correctness, robustness, and practicality challenges
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
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Infestações do ácaro Calepitrimerus vitis foram verificadas nas Ăşltimas safras nos parreirais do Sul do Brasil, entre os meses de dezembro e março. A espĂ©cie ataca somente videira e provoca deformações nas folhas, queda prematura e atĂ© mesmo atraso no desenvolvimento das plantas. A eliminação de restos de poda durante o inverno Ă© importante esttratĂ©gia de controle, porque nesse perĂodo as fĂŞmeas ficam alojadas nas reentrâncias dos ramos e no interior das brácteas das gemas
First insights into the microbiology of three antarctic briny systems of the northern Victoria land
Different polar environments (lakes and glaciers), also in Antarctica, encapsulate brine pools characterized by a unique combination of extreme conditions, mainly in terms of high salinity and low temperature. Since 2014, we have been focusing our attention on the microbiology of brine pockets from three lakes in the Northern Victoria Land (NVL), lying in the Tarn Flat (TF) and Boulder Clay (BC) areas. The microbial communities have been analyzed for community structure by next generation sequencing, extracellular enzyme activities, metabolic potentials, and microbial abundances. In this study, we aim at reconsidering all available data to analyze the influence exerted by environmental parameters on the community composition and activities. Additionally, the prediction of metabolic functions was attempted by the phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt2) tool, highlighting that prokaryotic communities were presumably involved in methane metabolism, aromatic compound biodegradation, and organic compound (proteins, polysaccharides, and phosphates) decomposition. The analyzed cryoenvironments were different in terms of prokaryotic diversity, abundance, and retrieved metabolic pathways. By the analysis of DNA sequences, common operational taxonomic units ranged from 2.2% to 22.0%. The bacterial community was dominated by Bacteroidetes. In both BC and TF brines, sequences of the most thermally tolerant and methanogenic Archaea were detected, some of them related to hyperthermophiles
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
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