Staphylococcus Biofilms

The majority of staphylococci produce biofilm on medical devices, which is the main mechanism to infect humans. Staphylococcal biofilms attach to abiotic or biotic surfaces, forming aggregates and protecting themselves against the immune system and the antimicrobial compounds of the host. Few studies on biofilm formation mechanism in Staphylococcus epidermidis and other coagulase-negative staphylococci (CNS) have been performed; however, there is a great interest in studying and controlling biofilm formation of this genus. This chapter exhibits the state of the art on biofilm formation in S. epidermidis and other staphylococcal species. The main goal of this chapter is to recognize the importance of biofilm formation in Staphylococcus. The participating molecules in staphylococcal biofilm formation are described. Currently, biofilm producer strains of Staphylococcus and mainly CNS have been frequently isolated at hospitals, causing significant economic losses. This chapter includes promising solutions in order to prevent medical device-associated infections, as the development of medical devices possessing anti-biofilm materials or surfaces that act against the adhesion or viability of the microorganisms

Surface Proteins of Staphylococcus aureus

Staphylococcus aureus is a commensal bacterium that causes infections such as sepsis, endocarditis, and pneumonia. S. aureus can express a variety of virulence factors, including surface proteins. Surface proteins are characterized by presence of a Sec‐dependent signal sequence at the amino terminal, and the sorting signal domain. Surface proteins are covalently attached to peptidoglycan and they are commonly known as cell wall–anchored (CWA) proteins. CWA proteins have many functions and participate in the pathogenesis of S. aureus. Furthermore, these proteins have been proposed as therapeutic targets for the generation of vaccines. In this chapter, different topics related to CWA proteins of S. aureus are addressed. The molecular structure of CWA proteins and their role as virulence factors of S. aureus are described. Furthermore, the involvement of CWA proteins in the processes of adhesion, invasion of host cells and tissues, evasion of the immune response, and the formation of biofilm is discussed. In addition, the role of CWA proteins in skin infection and the proposal to use them as potential vaccine antigens are described. The information contained in this chapter will help the readers to understand the biology of CWA proteins and to recognize the importance of surface molecules of S. aureus

Detecting optical transients using artificial neural networks and reference images from different surveys

We present a technique to detect optical transients based on an artificial neural networks method. We describe the architecture of two networks capable of comparing images of the same part of the sky taken by different telescopes. One image corresponds to the epoch in which a potential transient could exist; the other is a reference image of an earlier epoch. We use data obtained by the Dr. Cristina V. Torres Memorial Astronomical Observatory and archival reference images from the Sloan Digital Sky Survey. We trained a convolutional neural network and a dense layer network on simulated source samples and then tested the trained networks on samples created from real image data. Autonomous detection methods replace the standard process of detecting transients, which is normally achieved by source extraction of a difference image followed by human inspection of the detected candidates. Replacing the human inspection component with an entirely autonomous method would allow for a rapid and automatic follow-up of interesting targets of opportunity. The toy-model pipeline that we present here is not yet able to replace human inspection, but it might provide useful hints to identify potential candidates. The method will be further expanded and tested on telescopes participating in the Transient Optical Robotic Observatory of the South Collaboration

Psoriatic Animal Models Developed for the Study of the Disease

Psoriasis is a skin disease mainly developed in humans, although it is also seen in monkeys and dogs. Animal models with psoriasis-like lesions have been a key factor for its understanding. Xenotransplants of human psoriatic skin in immunodeficient mice were the first approach for the association of immunologic problems with the development of psoriasis and have been also useful for the evaluation on new therapeutic agents. Imiquimod-induced murine psoriasis is nowadays one of the most used animal models to study this disease, perhaps because healthy wild-type mice are used, which means that it is an affordable model, easy to generate, and, more importantly, resembles the inflammatory, angiogenic and hyperproliferative characteristics of human psoriasis. Several transgenic (over-expressing VEGF, Tie2, TGFβ, STAT3, IL-36, PPARβ/γ) and knockout (lacking IκBα, JunB, IFNR-2, IL-36RA, CD18, IKK2) mice have been useful for the association of specific molecules for the development of psoriasis. Other approach has been the use of both transgenic/knockout mice and imiquimod treatment, where the importance of βTrCP, IκBζ, IL-35 and Tnip1 for the development of psoriasis was found. In this chapter, some of these animal models are discussed

Cátedra empresarial Silicon Graphics : Un ejemplo de colaboración Universidad - Empresa

Este artículo presenta el mecanismo de colaboración Universidad - Empresa denominado Cátedra Empresarial, y en particular el suscrito entre Prosis- Procálculo y la Universidad de Los Andes, cuyo tema de investigación son los Sistemas de Información Geográfica. Se tratan detalladamente los objetivos perseguidos por esta colaboración, las metas y compromisos de las dos partes, un resumen de las actividades realizadas durante los años 1994 y 1995 y por último algunas conclusiones y comentarios sobre esta experiencia

Observations of the first electromagnetic counterpart to a gravitational wave source by the TOROS collaboration

We present the results of prompt optical follow-up of the electromagnetic counterpart of GW170817 by the Transient Optical Robotic Observatory of the South Collaboration (TOROS). We detected highly significant dimming in the light curves of the counterpart over the course of only 80 minutes of observations obtained ∼35 hr after the trigger with the T80-South telescope. A second epoch of observations, obtained ∼59 hr after the event with the EABA 1.5m telescope, confirms the fast fading nature of the transient. The observed colors of the counterpart suggest that this event was a blue kilonova relatively free of lanthanides

Analysis of first LIGO science data for stochastic gravitational waves

We present the analysis of between 50 and 100 h of coincident interferometric strain data used to search for and establish an upper limit on a stochastic background of gravitational radiation. These data come from the first LIGO science run, during which all three LIGO interferometers were operated over a 2-week period spanning August and September of 2002. The method of cross correlating the outputs of two interferometers is used for analysis. We describe in detail practical signal processing issues that arise when working with real data, and we establish an observational upper limit on a f−3 power spectrum of gravitational waves. Our 90% confidence limit is Ω0h210

The NALP3/Cryopyrin-Inflammasome Complex is Expressed in LPS-Induced Ocular Inflammation

In the inflammosome complex, NALP3 or NALP1 binds to ASC and activates caspase-1 which induces IL-1β. In murine LPS-induced ocular inflammation, the production of IL-1β is increased. We suggest that NALP3- or NALP1-inflammasome complex can be participating in the LPS-induced ocular inflammation. In this work, eye, brain, testis, heart, spleen, and lung were obtained from C3H/HeN mice treated with LPS for 3 to 48 hours, and the expression of NALP1b, NALP3, ASC, caspase-1, IL-1β, and IL-18 was determined. Infiltrated leukocytes producing IL-1β in the anterior chamber were found at 12-hour posttreatment. A high upregulated expression of NALP3, ASC, caspase-1, IL-1β, and IL-18 was found at the same time when infiltrated leukocytes were observed. NALP1b was not detected in the eye of treated mice. NALP3 was also overexpressed in heart and lung. These results suggest that NALP3-, but not NALP1-inflammosome complex, is participating in the murine LPS-induced ocular inflammation

Upper Limits on a Stochastic Background of Gravitational Waves

The Laser Interferometer Gravitational-Wave Observatory has performed a third science run with much improved sensitivities of all three interferometers. We present an analysis of approximately 200 hours of data acquired during this run, used to search for a stochastic background of gravitational radiation. We place upper bounds on the energy density stored as gravitational radiation for three different spectral power laws. For the flat spectrum, our limit of Ω