La malattia diverticolare complicata: studio retrospettivo di 96 casi

La malattia diverticolare complicata del colon è una patologia che ha ancora oggi notevoli implicazioni sulla morbidità e mortalità del paziente. Per tale motivo l'attenzione dei chirurghi è volta all'ottimizzazione del trattamento sia medico che chirurgico. A tale proposito nasce l'esigenza di individuare i pazienti ad "alto rischio" di morbidità e mortalità in seguito ad un episodio di diverticolite complicata, al fine di proporre loro un intevento resettivo già dopo il primo episodio acuto. In questo studio è stato valutato il rapporto tra "elevato rischio" ed età avanzata, sesso femminile e alcune comorbidità

Electrical and ultraviolet characterization of 4H-SiC Schottky photodiodes

Fabrication and electrical and optical characterization of 4H-SiC Schottky UV photodetectors with nickel silicide interdigitated contacts is reported. Dark capacitance and current measurements as a function of applied voltage over the temperature range 20 °C – 120 °C are presented. The results show consistent performance among devices. Their leakage current density, at the highest investigated temperature (120 °C), is in the range of nA/cm2 at high internal electric field. Properties such as barrier height and ideality factor are also computed as a function of temperature. The responsivities of the diodes as functions of applied voltage were measured using a UV spectrophotometer in the wavelength range 200 nm - 380 nm and compared with theoretically calculated values. The devices had a mean peak responsivity of 0.093 A/W at 270 nm and −15 V reverse bias

A new pathogen transmission mechanism in the ocean: the case of sea otter exposure to the land-parasite Toxoplasma gondii.

Toxoplasma gondii is a land-derived parasite that infects humans and marine mammals. Infections are a significant cause of mortality for endangered southern sea otters (Enhydra lutris nereis), but the transmission mechanism is poorly understood. Otter exposure to T. gondii has been linked to the consumption of marine turban snails in kelp (Macrocystis pyrifera) forests. It is unknown how turban snails acquire oocysts, as snails scrape food particles attached to surfaces, whereas T. gondii oocysts enter kelp beds as suspended particles via runoff. We hypothesized that waterborne T. gondii oocysts attach to kelp surfaces when encountering exopolymer substances (EPS) forming the sticky matrix of biofilms on kelp, and thus become available to snails. Results of a dietary composition analysis of field-collected snails and of kelp biofilm indicate that snails graze the dense kelp-biofilm assemblage composed of pennate diatoms and bacteria inserted within the EPS gel-like matrix. To test whether oocysts attach to kelp blades via EPS, we designed a laboratory experiment simulating the kelp forest canopy in tanks spiked with T. gondii surrogate microspheres and controlled for EPS and transparent exopolymer particles (TEP - the particulate form of EPS). On average, 19% and 31% of surrogates were detected attached to kelp surfaces covered with EPS in unfiltered and filtered seawater treatments, respectively. The presence of TEP in the seawater did not increase surrogate attachment. These findings support a novel transport mechanism of T. gondii oocysts: as oocysts enter the kelp forest canopy, a portion adheres to the sticky kelp biofilms. Snails grazing this biofilm encounter oocysts as 'bycatch' and thereby deliver the parasite to sea otters that prey upon snails. This novel mechanism can have health implications beyond T. gondii and otters, as a similar route of pathogen transmission may be implicated with other waterborne pathogens to marine wildlife and humans consuming biofilm-feeding invertebrates

Utilizando a análise de modo e efeitos de falha potencial (FMEA) para atingir a conformidade com o padrão de segurança dos dados do setor de cartões de pagamento (PCI DSS)

Com o avanço na utilização de diferentes tipos de cartões magnéticos para pagamento de transações financeiras, a preocupação com a segurança das informações armazenadas, transmitidas e processadas torna - se foco prioritário para a s empresas que fazem parte deste negócio. Visando garantir a segurança dos dados desses cartões, algumas das principais operadoras compartilharam experiências e criaram um conjunto de políticas e procedimentos denominado Padrão de Segurança de Dados (DSS) do Setor de Cartões de Pagamento (PCI). Considerando a crescente incidência de fraudes e ataques que ameaçam a continuidade e imagem das empresas que atuam nesta cadeia de valor, este trabalho apresenta uma proposta para fortalecer o processo de obtenção de conformidade com a certificação utilizando a ferramenta de Análise de Modo e Efeito das Falhas (FMEA). Partindo da revisão bibliográfica sobre o tema, a solução proposta apresenta uma forma de utilização do FMEA enquanto ferramenta para obtenção da cert ificação PCI DSS. Os resultados desta solução são apresentados mostrando a utilização de uma ferramenta utilizada por empresas do ramo automotivo na área de segurança da informaçã

Aquatic polymers can drive pathogen transmission in coastal ecosystems.

Gelatinous polymers including extracellular polymeric substances (EPSs) are fundamental to biophysical processes in aquatic habitats, including mediating aggregation processes and functioning as the matrix of biofilms. Yet insight into the impact of these sticky molecules on the environmental transmission of pathogens in the ocean is limited. We used the zoonotic parasite Toxoplasma gondii as a model to evaluate polymer-mediated mechanisms that promote transmission of terrestrially derived pathogens to marine fauna and humans. We show that transparent exopolymer particles, a particulate form of EPS, enhance T. gondii association with marine aggregates, material consumed by organisms otherwise unable to access micrometre-sized particles. Adhesion to EPS biofilms on macroalgae also captures T. gondii from the water, enabling uptake of pathogens by invertebrates that feed on kelp surfaces. We demonstrate the acquisition, concentration and retention of T. gondii by kelp-grazing snails, which can transmit T. gondii to threatened California sea otters. Results highlight novel mechanisms whereby aquatic polymers facilitate incorporation of pathogens into food webs via association with particle aggregates and biofilms. Identifying the critical role of invisible polymers in transmission of pathogens in the ocean represents a fundamental advance in understanding and mitigating the health impacts of coastal habitat pollution with contaminated runoff

Análisis de la asociación entre procalcitonina y mortalidad por sepsis en menores de 18 años en una unidad de cuidados intensivos, Pasto- Colombia 2012 - 2014

Introduction: Procalcitonin increases early in patients with sepsis; however, it is necessary to deepen the relationship between their levels and the multi-organ commitment, as well as their outcomes such as death. Objective: To determine whether there is an association between the values of Procalcitonin and death in children with sepsis entering the pediatric intensive care unit (PICU). Materials and methods: A cross-sectional study was made with patients under 18 years of age with sepsis, who entered the PICU of Los Angeles children's Hospital in Pasto, Colombia during 2012 and 2014. The relationship between the risk of death and the levels of Procalcitonin controlled by clinical and demographic covariates was analyzed. Results: Data from 325 patients with sepsis was analyzed. The disease showed a prevalence of 27.3%, from which 23.7% (77) died. The median age was 22 months, interquartile-RI range (6-84). The median Procalcitonin was 10 ng/mL, RI (2.95-38). Children with values > 10ng/mL have an increase in the risk of death from 2 to 6 times more, compared to those who presented lower values. Conclusion: Procalcitonin can be used as an indicator and predictor of the risk of death in children under 18 with sepsis

Quartz Cherenkov Counters for Fast Timing: QUARTIC

We have developed particle detectors based on fused silica (quartz) Cherenkov radiators read out with micro-channel plate photomultipliers (MCP-PMTs) or silicon photomultipliers (SiPMs) for high precision timing (Sigma(t) about 10-15 ps). One application is to measure the times of small angle protons from exclusive reactions, e.g. p + p - p + H + p, at the Large Hadron Collider, LHC. They may also be used to measure directional particle fluxes close to external or stored beams. The detectors have small areas (square cm), but need to be active very close (a few mm) to the intense LHC beam, and so must be radiation hard and nearly edgeless. We present results of tests of detectors with quartz bars inclined at the Cherenkov angle, and with bars in the form of an "L" (with a 90 degree corner). We also describe a possible design for a fast timing hodoscope with elements of a few square mm.Comment: 24 pages, 14 figure

Electrical Characterization of SiPM as a Function of Test Frequency and Temperature

Silicon Photomultipliers (SiPM) represent a promising alternative to classical photomultipliers, for instance, for the detection of photons in high energy physics and medical physics. In the present work, electrical characterizations of test devices - manufactured by ST Microelectronics - are presented. SiPMs with an area of 3.5x3.5 micron^2 and a cell pitch of 54 micron were manufactured as arrays of 64x64 cells and exhibiting a fill factor of 31%. The capacitance of SiPMs was measured as a function of reverse bias voltage at frequencies ranging from from 20 Hz up to 1 MHz and temperatures from 300 K down to 85 K. While leakage currents were measured at temperatures from 400 K down to 85 K. Thus, the threshold voltage - i.e., voltage corresponding to that at which the multiplication regime for the leakage current begins - could be determined as a function of temperature. Finally, an electrical model suited to reproduce the dependence of the frequency dependence of capacitance is presented.Comment: To appear on the Proceedings of the 13th ICATPP Conference on Astroparticle, Particle, Space Physics and Detectors for Physics Applications, Villa Olmo (Como, Italy), 3-7 October, 2011, to be published by World Scientific (Singapore

4H-SiC Schottky diodes with Ni2Si contacts for X-ray detection

4H-SiC Schottky photodiodes, with epitaxial layers, employing thin (20 nm) Ni2Si Schottky contacts, were investigated for high temperature photon counting X-ray spectroscopy. Important X-ray photodiode detector parameters were extracted from electrical characterization within the temperature range 160 °C to 0 °C. The devices were found to be fully depleted at an applied electric field of 20 kV/cm; a leakage current density of 33 nA cm 1 nA cm−2 at 160 °C, was measured for one of the devices. The detectors were subsequently connected to low-noise photon counting readout electronics and investigated for their spectral performance at temperatures up to 100 °C. With the charge-sensitive preamplifier operated at the same temperature as the detector the best energy resolution (Full Width at Half Maximum at 5.9 keV) obtained decreased from 2.20 keV 0.04 keV (120 e rms 2 e rms) at 100 C to 1.20 keV 0.03 keV (65 e rms 2 e rms) at 0 C. The dominant source of noise broadening the 55Fe X-ray photopeak was found to be the dielectric noise, except for the spectra accumulated at 100 °C and long shaping times (>), in those case the main source of photopeak broadening was the white parallel noise