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The rise of infections caused by multi-resistant gram-negative bacilli (MR-GNB), which includes carbapenems, represents one of the major current challenges worldwide. These MR-GNB include extended spectrum β-lactamase-producing Enterobacterales, derepressed AmpC-producing or carbapenemase-producing Enterobacterales as well as non-fermenting Gram-negative bacilli such as Pseudomonas aeruginosa or Acinetobacter baumannii. P. aeruginosa predominantly exhibits other resistance mechanisms different to β-lactamases such as expulsion pumps or loss of porins. A. baumannii frequently presents several of these resistance mechanisms. Mortality is high especially if empirical treatment is inadequate. In this review, treatment strategies are revised, describing the tools available to identify patients in whom empirical antibiotic treatment would be justified to cover MR-GNB, the importance of optimizing the administration of these antibiotics, as well as prevention strategies to avoid its spread from patients colonized or infected by a MR-GNB. more...

Resumen En este trabajo se tuvo como objetivo analizar las competencias de futuros profesores de pedagogía en enseñanza media en matemáticas, al hacer transformaciones de las representaciones de una función. La información se recogió en el segundo semestre de 2019 y se procesó utilizando la técnica análisis de contenido. Es un trabajo cualitativo, donde se interactuó con docentes en formación, mientras resolvían situaciones problema que involucraban funciones y preparaban una clase, que luego simulaban ante su grupo de clase y su docente. La muestra la constituyeron 36 sujetos estudiantes del profesorado en matemáticas de una universidad chilena. Los resultados muestran que lograron producir múltiples formas de representación de las relaciones funcionales analizadas, lo que facilitaba el análisis y establecimiento de conexiones con elementos del contexto sociocultural, pero una parte del grupo presentó dificultades con la fluidez perceptual, lo que impidió establecer conexiones entre ellas. Fueron modificando los significados parciales de la función, articuladamente, hasta ubicarse en uno de ellos, desde donde produjeron y articularon sus múltiples representaciones. Se concluye sobre la necesidad de implementar procesos de intervención que lleven a los futuros profesores a hacer análisis más integrales de las funciones, que le faciliten hacer un uso operativo de sus conocimientos, para minimizar las dificultades de aprendizaje en sus estudiantes. Abstract This paper aimed to analyze the competencies of pre-service secondary school mathematics teachers when transforming the representations of a function. The information was collected during the second half of 2019 and was processed using the content analysis technique. For this qualitative study, researchers interacted with pre-service teachers while they solved problems involving functions and prepared a class that they later simulated before their professor and classmates. The sample included 36 students from the Mathematics Education Program of a Chilean university. Results show that pre-service teachers were able to produce multiple ways of representations of the analyzed functional relationships, which facilitated the analysis and establishment of connections with sociocultural elements. However, some participants faced difficulties with perceptual fluency, which prevented them from establishing connections. The partial meanings of the functions were articulately modified until they became one, in which time multiple representations were produced and articulated. In conclusion, interventional processes should be implemented to help future teachers make more comprehensive analyzes of functions and have an operational use of their knowledge, in order to minimize learning difficulties in students. Resumo Este trabalho teve como objetivo analisar as competências de futuros professores de pedagogia no ensino médio em matemática, ao fazer transformações das representações de uma função. A informação foi coletada no segundo semestre de 2019 e processada com o uso do método de análise de conteúdo. É um trabalho qualitativo, no qual houve uma interação com docentes em formação, enquanto resolviam situações problema que envolviam funções e preparavam uma aula, que logo simulavam diante de seu grupo da sala e de seu docente. A amostra esteve composta de 36 sujeitos estudantes da faculdade de matemática de uma universidade chilena, com os quais interagiram na preparação e na simulação de uma aula sobre a noção função. Os resultados mostram que conseguiram produzir múltiplas formas de representação das relações funcionais analisadas, o que facilitava a análise e o estabelecimento de conexões com elementos do contexto sociocultural, porém uma parte do grupo apresentou dificuldades com a fluidez perceptual, impedindo estabelecer conexões entre elas. Foram modificando os significados parciais da função, articuladamente, até localizar-se em um deles, desde onde produziram e articularam suas múltiplas representações. Conclui-se sobre a necessidade de implementar processos de intervenção que guie os futuros professores a fazer análises mais integrais das funções, o que facilita fazer um uso operativo de seus conhecimentos e, assim, minimizar as dificuldades de aprendizagem em seus estudantes. more...

En este trabajo se evalúa la dimensión matemática del Conocimiento Didáctico-Matemático de futuros profesores de matemáticas, al hacer transformaciones de las representaciones de una función. Se aplicó un cuestionario a 90 profesores en formación repartidos en tres grupos; fue analizada la homogeneidad de las respuestas por grupos, y se caracterizaron los objetos matemáticos primarios y procesos presentes en las prácticas matemáticas que desarrollan los profesores en formación al resolver el cuestionario. Los resultados evidencian serias dificultades de los mismos para identificar y usar los interceptos de una función sin ayuda gráfica; analizar sus valores extremos y sus intervalos de crecimiento; modelarla matemáticamente e identificar la pendiente de una función lineal. Los objetos matemáticos primarios y procesos presentes en las prácticas que desarrollan los estudiantes al hacer transformaciones de las representaciones de las funciones involucradas en la situación son muy similares, a pesar de la diferencia en horas desarrolladas en el programa en cada uno de los tres niveles. more...

Laser Beam Welding (LBW) is an advanced process to join materials with a laser beam of high energy density. LBW is especially suitable to join titanium alloys, as it allows high localization and low size of the melting pool, reducing considerably the energy of the process, in comparison with other welding technologies. Among the two widely known welding regimes, conduction and keyhole, the former is claimed to be a viable alternative to keyhole, mainly because it is a very stable process, provides high-quality welds free of defects, and involves lower laser cost. In the present work, a Finite Element Method (FEM) has been developed to simulate the LBW of Ti6Al4V alloy under conduction regime. The “Goldak double ellipsoid model” has been taken for the first time to simulate this LBW conduction process. In order to refine and validate the model, experimental conduction welding tests were performed on Ti6Al4V pieces with a high-power diode laser. Microstructural analyses and hardness measurements were also performed on the laser weld beads to identify the generated phases. Distortion and residual stresses were also obtained from the FEM simulations. An excellent agreement between the simulation and experimental results was found regarding the bead morphology and phase transformations. more...

The inherent architectural and chemical complexities of microbial biofilms mask our understanding of how these communities form, survive, propagate, and influence their surrounding environment. Here we describe a simple and versatile workflow for the cultivation and characterization of model flow-cell-based microbial ecosystems. A customized low-shear drip flow reactor was designed and employed to cultivate single and coculture flow-cell biofilms at the air-liquid interface of several metal surfaces. Pseudomonas putida F1 and Shewanella oneidensis MR-1 were selected as model organisms for this study. The utility and versatility of this platform was demonstrated via the application of several chemical and morphological imaging techniques-including matrix-assisted laser desorption/ionization mass spectrometry imaging, secondary ion mass spectrometry imaging, and scanning electron microscopy-and through the examination of model systems grown on iron substrates of varying compositions. Implementation of these techniques in combination with tandem mass spectrometry and a two-step imaging principal component analysis strategy resulted in the identification and characterization of 23 lipids and 3 oligosaccharides in P. putida F1 biofilms, the discovery of interaction-specific analytes, and the observation of several variations in cell and substrate morphology present during microbially influenced corrosion. The presented workflow is well-suited for examination of both single and multispecies drip flow biofilms and offers a platform for fundamental inquiries into biofilm formation, microbe-microbe interactions, and microbially influenced corrosion. more...

Titanium dioxide (TiO2) is a photocatalyst widely used for the degradation of inorganic and organic contaminants in the environment; however, its lack of chemical specificity can be a particular limitation since every species in solution, including valued, innocuous, and deactivating compounds, will be degraded or deleterious to the process. Here, we describe a means to target the photocatalysis by surface modification of nanoparticulate TiO2 with a 13 amino acid streptavidin binding peptide (SBP) for the selective degradation of streptavidin, a 60 kDa tetrameric protein. Modification of the TiO2 surface with the affinity peptide was confirmed by fourier transform infrared spectroscopy (FTIR), UV/Vis absorbance, and secondary ion mass spectrometry (SIMS), while streptavidin binding and affinity to bound SBP were tested using fluorescently tagged antibodies against streptavidin. Results show that the SBP retains its affinity toward streptavidin after immobilization onto TiO2. Photodegradation studies using the visible region of simulated solar radiation (≥360 nm) showed rapid streptavidin degradation by SBP–TiO2 both in solution and while the photocatalyst was immobilized as a thin film on a glass substrate. In contrast, photocatalytic degradation of a non-target protein, lysozyme, was inhibited by the SBP monolayer and incompletely degraded, indicating that surface modification with biorecognition agents can control and modulate the photocatalytic process. Moreover, after extended illumination (3 h), the SBP-modified TiO2 surface retained its ability to bind streptavidin demonstrating that the SBP is stable at the TiO2 surface and that the SBP–TiO2 surface is reusable. These results indicate that the modification of TiO2 with covalently bound peptide recognition moieties offers the ability to selectively degrade target proteins of interest, leaving non-target components largely unaffected. more...

Preflattened veal cutlets (ca. 71.5 g, ca. 0.32 cm thick) were surface inoculated with ca. 6.8 log CFU/g of a multistrain cocktail of Escherichia coli O157:H7 (ECOH) or a cocktail made of single strains of serogroups O26, O45, O103, O104, O111, O121, and O145 of Shiga toxin-producing E. coli (STEC) cells and then were mechanically tenderized by passing once through a "Sir Steak" tenderizer. For each cooking time, in each of at least three trials, three inoculated and tenderized cutlets, with and without breading, were individually cooked in 15 or 30 ml of canola oil for 0.0, 0.75, 1.0, 1.25, 1.5, 1.75, or 2.25 min per side on an electric skillet set at 191.5°C. The temperatures of the meat and of the skillet were monitored and recorded using a type J thermocouple. Regardless of the breading or volume of oil used to cook the meat, the longer the cooking times, the higher was the internal temperature of the meat, along with a greater reduction of both ECOH and STEC. The average final internal temperature of the meat at the approximate geometric center ranged from 56.8 to 93.1°C. Microbial reductions of ca. 2.0 to 6.7 log CFU/g and ca. 2.6 to 6.2 log CFU/g were achieved for ECOH and STEC, respectively. Our data also revealed no differences in thermal inactivation of ECOH relative to the volume of oil used to cook nonbreaded cutlets. However, when cooking breaded cutlets, the use of more (30 ml) compared with less (15 ml) cooking oil resulted in greater reductions in pathogen numbers. To deliver about a 5.0-log reduction of ECOH and STEC, and to achieve the recommended internal temperature of 71.1°C, it was necessary to cook mechanically tenderized veal cutlets for at least 1.5 min per side on a preheated electric skillet set at 191.5°C and containing 15 ml of cooking oil. These data also established that cooking times and temperatures effective for inactivating serotype O157:H7 strains of E. coli in tenderized veal are equally effective against the additional six non-O157 Shiga toxin-producing strains investigated herein. more...

In the present study, Ti6Al4V samples have been welded under conduction regime by means of a high power diode laser. The main objective of the work has been to determine the actual influence of the surface pre-treatments on the laser welding process. Thus, six different pre-treatments were applied to Ti6Al4V samples before performing bead-on-plate and butt welding treatments. The depth, width, microstructure, and microhardness of the different weld zones were deeply analyzed. Grinding, sandblasting, and chemical cleaning pre-treatments lead to welds with the highest depth values, presenting high joint strengths. Treatments based on the application of dark coatings generate welds with lower penetration and worse mechanical properties, specially the graphite-based coating. more...

The management of critically ill burn patients is challenging. These patients have to be managed in specialized centers, where the expertise of physicians and nursing personnel guarantees the best treatment. Mortality of burn patients has improved over the past decades due to a better understanding of burn shock pathophysiology, optimal surgical management, infection control and nutritional support. Indeed, a more aggressive resuscitation, early excision and grafting, the judicious use of topical antibiotics, and the provision of an adequate calorie and protein intake are key to attain best survival results. General advances in critical care have also to be implemented, including protective ventilation, glycemic control, selective decontamination of the digestive tract, and implementation of sedation protocols. more...

Welding characteristics of Ti-5Al-5V-5Mo-3Cr (Ti5553) alloy has been investigated. The weld joints were performed by laser beam (LBW), electron beam (EBW) and gas tungsten arc welding (GTAW). Regardless of the welding method used, the welds showed low hardness values with coarse columnar grains in the fusion zone (FZ) and retained equiaxed beta phase within the heat affected zone (HAZ). Larger grains were present at the near HAZ compared with far HAZ (near base metal). The strengths of the welded samples were lower than the base metal. Fracture occurred at the weld zones with transgranular and microvoid coalescence fracture mechanism. more...

This work targets the miniaturization of bidirectional isolated dc-dc converters for renewable energy applications with integrated energy storage. A power IC was fabricated in a 0.18μm 80V BCD process to integrate the primary-side low-voltage bridge in Dual-Active-Bridge (DAB) converter. The targeted power level of the converter is 50 W per IC, with a high switching frequency of 1 MHz. A Phase-Locked-Loop (PLL) based synchronization scheme is used to reduce the number of digital isolators to transmit gating pulse. The IC includes the power-stage, drivers, protection features, communication transceivers, PLL synchronization and 12-bit phase-shift module for precise power control. High-frequency isolated communication is demonstrated at 167 MHz using an air-core PCB based transformer. The soft-switching converter achieves a peak efficiency of 94% at 1 MHz. more...

In highland Bolivia, potato markets are widespread and access to market information has entered the digital age. Information networks lubricated by ubiquitous cellular technologies are supplanting traditional means of information-gathering. We explore the impacts of access to cellular phones on market selection, use of social networks to acquire information, and gendered responsibilities within the potato market chain near Cochabamba. The entire family participates in potato production and marketing, but responsibilities are differentiated by gender. Men take a leading role in potato production and women in marketing. Access to cellular phones affects decisions about where to market potatoes and improves the potato marketing process. more...

In the present work, the correlation between the metallographic evaluation and electrochemical noise (EN) in intergranular corrosion (IGC) tests of aluminium alloy 2024-T3 has been analysed. For this purpose, the influence of temperature and hydrogen peroxide concentration on the IGC attack has been studied. Similar IGC was observed between 20 and 40 °C, showing a low dependence with temperature (at least in this range). Hydrogen peroxide was seen to have a strong effect, leading to IGC activation when raising its concentration. The results of the detailed metallographic evaluation of the samples after the tests were analysed together with the EN measured during the tests. The averaged noise resistance was inversely proportional to the depths of the attacks, whereas the average of the parameter so-called ‘Statistical Noise Power’ was directly related to the IGC degree. The metallographic evaluation and the EN showed a reasonable experimental correlation. Copyright © 2012 John Wiley & Sons, Ltd. more...

The application of laser beam welding to aluminium alloys has some complications, mainly due to their high reflectivity, high thermal conductivity and low viscosity. In order to increase the laser absorption of aluminium alloys, some surface treatments has been applied in the literature, such as the application of dark coatings or sandblasting. However, these conventional superficial treatments have some drawbacks, such as the low weld penetration, the possibility to undergo magnesium evaporation and the impossibility to control and/or change the superficial properties of the treated samples. In the present contribution, laser texturization treatments have been performed with a fibber laser for the first time on aluminium alloys to increase their absorption and weld penetration. The texturised samples leaded to deeper bead welds than the reference sandblasted samples. more...

The high strength, low density and superior corrosion resistance allow titanium alloys to be widely employed in different industrial applications. The properties of these alloys can be modulated by different heat treatments, including laser processing. In the present paper, laser remelting treatments, performed with a high power diode laser, were applied to samples of two titanium alloys (TiG2 and Ti6Al4V). The influence of the applied laser fluence on microstructure, microhardness and corrosion resistance is investigated. Results show that laser remelting treatments with appropriate fluences provoke microstructural changes leading to microhardness increase and corrosion resistance improvement. more...

Laser beam welding (LBW) show clear advantages compared with other techniques, as the low heat input, the high localization ability, the high welding speed, the high flexibility, the high weld quality and the high production rate. However, its applicability to aluminium alloys is limited, as they generally have high reflectivity, high thermal conductivity and low viscosity. In the present study, the laser weldability of four aluminium alloys (2024, 5083, 6082 and 7075) under conduction regime is analysed. High penetration butt welds could be obtained with a High Power Diode Laser (HPDL) under conduction regime. The properties of the weld beads such as the microstructure and microhardness were analysed. A linear function between the input laser fluence and the volume of melted material was obtained for the four alloys. more...

Fatty acids are central to brain metabolism and signaling, but their distributions within complex brain circuits have been difficult to study. Here we applied an emerging technique, time-of-flight secondary ion mass spectrometry (ToF-SIMS), to image specific fatty acids in a favorable model system for chemical analyses of brain circuits, the zebra finch (Taeniopygia guttata). The zebra finch, a songbird, produces complex learned vocalizations under the control of an interconnected set of discrete, dedicated brain nuclei 'song nuclei'. Using ToF-SIMS, the major song nuclei were visualized by virtue of differences in their content of essential and non-essential fatty acids. Essential fatty acids (arachidonic acid and docosahexaenoic acid) showed distinctive distributions across the song nuclei, and the 18-carbon fatty acids stearate and oleate discriminated the different core and shell subregions of the lateral magnocellular nucleus of the anterior nidopallium. Principal component analysis of the spectral data set provided further evidence of chemical distinctions between the song nuclei. By analyzing the robust nucleus of the arcopallium at three different ages during juvenile song learning, we obtain the first direct evidence of changes in lipid content that correlate with progression of song learning. The results demonstrate the value of ToF-SIMS to study lipids in a favorable model system for probing the function of lipids in brain organization, development and function. more...

Differences in trauma patients developing ventilator-associated pneumonia (VAP) are described regarding etiology and risk factors associated. We aim to describe the differences in outcomes in trauma and nontrauma patients with VAP.A prospective, observational study conducted in 27 intensive care units from nine European countries. We included patients requiring invasive mechanical ventilation for48 hours who developed VAP. Logistic regression model was used to assess the factors independently associated with mortality in trauma patients with VAP.A total of 2,436 patients were evaluated; 465 developed VAP and of these 128 (27.5%) were trauma patients. Trauma patients were younger than nontrauma (45.3 ± 19.4 vs. 61.1 ± 16.7, p0.0001). Nontrauma had higher simplified acute physiology score II compared with trauma patients (45.5 ± 16.3 vs. 41.1 ± 15.2, p = 0.009). Most prevalent pathogens in trauma patients with early VAP were Enterobacteriaceae spp. (46.9% vs. 27.8%, p = 0.06) followed by methicillin-susceptible Staphylococcus aureus (30.6% vs. 13%, p = 0.03) and then Haemophilus influenzae (14.3% vs. 1.9%, p = 0.02), and the most prevalent pathogen in late VAP was Acinetobacter baumannii (12.2% vs. 44.4%, p0.0001). Mortality was higher in nontrauma patients than in trauma patients (42.6% vs. 17.2%, p0.001, odds ratio [OR] = 3.55, 95%CI = 2.14-5.88). A logistic regression model adjusted for sex, age, severity of illness at intensive care unit admission, and sepsis-related organ failure assessment score at the day of VAP diagnosis confirmed that trauma was associated with a lower mortality compared with nontrauma patients (odds ratio [OR] = 0.37, 95%CI = 0.21-0.65).Trauma patients developing VAP had different demographic characteristics and episodes of etiology. After adjustment for potential confounders, VAP episodes in trauma patients are associated with lower mortality when compared with nontrauma patients. more...

La patología neuromuscular en los pacientes críticos ha comenzado a ser objeto de un importante número de estudios en los últimos años, si bien aún quedan muchas lagunas en el conocimiento de su etiología, patogenia, tratamiento y pronóstico. Dentro de esta patología debemos distinguir dos grandes grupos. En el primero, la debilidad muscular aparece antes del ingreso en UCI y es posible identificar una causa conocida. El síndrome de Guillain-Barré y la miastenia grave son las dos entidades que con mayor frecuencia requieren ser atendidas en nuestras unidades. En el segundo grupo, la debilidad muscular se adquiere en la UCI, en pacientes sin enfermedad neuromuscular previa, y es secundaria a la gravedad de la enfermedad que originó su ingreso en esta unidad y/o al tratamiento empleado. La polineuropatía del paciente crítico (PPC) es, de todas ellas, la entidad más precisamente definida y de la que conocemos mejor sus características clínicas, diagnóstico y pronóstico; no obstante, aún quedan muchas sombras en cuanto a su etiopatogenia. Las alteraciones de la placa neuromuscular y sobre todo la miopatía, que frecuentemente coexiste con la PPC, son las otras complicaciones del sistema nervioso periférico que se desarrollan en pacientes críticos. Los avances en el conocimiento de estas afecciones podrían tener un importante impacto, sobre todo para el desarrollo de intervenciones terapéuticas y preventivas efectivas que mejoren el pronóstico de estos pacientes. more...

The management of critically ill burn patients is challenging. These patients have to be managed in specialized centers, where the expertise of physicians and nursing personnel guarantees the best treatment. Mortality of burn patients has improved over the past decades due to a better understanding of burn shock pathophysiology, optimal surgical management, infection control and nutritional support. Indeed, a more aggressive resuscitation, early excision and grafting, the judicious use of topical antibiotics, and the provision of an adequate calorie and protein intake are key to attain best survival results. General advances in critical care have also to be implemented, including protective ventilation, glycemic control, selective decontamination of the digestive tract, and implementation of sedation protocols. El manejo de enfermos quemados críticos supone un gran reto para el clínico. Estos pacientes han de ser tratados en centros especializados, donde la experiencia del personal médico y de enfermería garantiza el mejor tratamiento. El pronóstico de los enfermos quemados ha mejorado durante las últimas décadas debido a una mejor comprensión de la fisiopatología del shock y a un mejor tratamiento quirúrgico, de la infección y soporte nutricional. La reanimación intensiva, el tratamiento quirúrgico más puntual, el uso juicioso del tratamiento tópico antimicrobiano y el aporte de la cantidad de nutrientes necesaria son aspectos clave FIS PI 12/02989 1.231 JCR (2016) Q4, 31/33 Critical Care Medicine UEM more...

Lipids have diverse functions in the nervous system, but the study of their anatomical distributions in the intact brain is rather difficult using conventional methodologies. Here we demonstrate the application of high resolution time-of-flight (ToF) secondary ion mass spectrometry (SIMS) to image various lipid components and cholesterol across an entire brain section prepared from an adult zebra finch (Taeniopygia guttata), with a spatial resolution of 2.3m, resulting in the formation of 11.5 megapixel chemical images. The zebra finch is a songbird in which specific neural and developmental functions have been ascribed to discrete “song control nuclei” of the forebrain. We have observed a relative increase of palmitic acid C16:0 and oleic acid C18:1 in song control nuclei versus the surrounding tissue, while phosphate (PO3 − ), representative of phospholipids, was lower in these regions. Cholesterol was present at a high level only in the white matter of the optic tectum. More diffuse distributions were observed for stearic, arachidonic, linolenic, and palmitoleic acids. The presented results illustrate that SIMS imaging is a useful approach for assessing changes in lipid content during song circuit development and song learning. © 2006 Elsevier B.V. All rights reserved. more...

Synchronous multicentric osteosarcoma, is a tumor with presentation in two or more sites without the appearance of lung metastasis. The incidence is 1 to 3% of all osteosarcomas and only less than 100 cases have been documented in the literature. In our case, we are presenting a six and a half year old patient with a painful tumor in the left thigh diagnosed with an incisional biopsy that reported a high grade conventional osteosarcoma in the left distal femur, a lesion in the contralateral limb in distal femur and proximal tibia, with no favorable response to chemotherapy. Lung and brain metastases were detected; therefore, we decided to give multidisciplinary palliative care for the disease. Years after its description there is still debate whether this condition really corresponds to a primary variable or to a manifestation of the metastatic disease. more...

A genetic selection system that detects splicing and nonsplicing activities of inteins was developed based on the ability to rescue a T4 phage strain with a conditionally inactive DNA polymerase. This phage defect can be complemented by expression of plasmid-encoded phage RB69 DNA polymerase. Insertion of an intein gene into the active site of the RB69 DNA polymerase gene renders polymerase activity and phage viability dependent on protein splicing. The effectiveness of the system was tested by screening for thermosensitive splicing mutants. Development of genetic systems with the potential of identifying protein splicing inhibitors is a first step towards controlling proliferation of pathogenic microbes harboring inteins in essential proteins. more...

A high-density transposon mutagenesis strategy was applied to the Haemophilus influenzae genome to identify genes required for growth or viability. This analysis detected putative essential roles for the products of 259 ORFs of unknown function. Comparisons between complete genomes defined a subset of these proteins in H. influenzae having homologs in Mycobacterium tuberculosis that are absent in Saccharomyces cerevisiae , a distribution pattern that favors their use in development of antimicrobial therapeutics. Three genes within this set are essential for viability in other bacteria. Interfacing the set of essential gene products in H. influenzae with the distribution of homologs in other microorganisms can detect components of unrecognized cellular pathways essential in diverse bacteria. This genome-scale phenotypic analysis identifies potential roles for a large set of genes of unknown function. more...

The Mycobacterium xenopi gyrase A mini-intein has been engineered to yield a controllable N-terminal or C-terminal, single- splice-junction autocleavage element. When combined with an affinity tag, these modified mini-inteins can be used to purify target proteins after a single combined chromatography/cleavage step. Cleavage at the intein N terminus was induced with thiol reagents, while cleavage at the intein C terminus was induced by a temperature shift to 16°–25°C. Different preferences for the residue immediately preceding the intein were observed during thiol-induced, N-terminal splice-junction cleavage of the M. xenopi gyrase A mini-intein vs. the Saccharomyces cerevisiae vacuolar ATPase, subunit A (VMA) intein present in the IMPACTTM purification system. Furthermore, the M. xenopi gyrase A mini-intein Cterminal autocleavage vector allows isolation of polypeptides with N-terminal cysteine residues that are active in the Intein Mediated Protein Ligation method of protein semisynthesis. more...

In this chapter, laser welding procedures employed in the literature to join aluminium and titanium alloys are reviewed. The chapter is divided into two main sections, comprising reviews of the literature on laser welding of aluminium alloys and titanium alloys, respectively. Each of these sections has an introductory part in which general concepts and specific properties influencing the weldability of alloys are described. Subsequently, the main experimental details of the reviewed papers are reported, including description of the laser equipment, welding modes, powers and processing rates, shielding gas, superficial pre-treatments of samples, etc. The microstructure, main defects, mechanical properties and corrosion behaviour of the weld beads are also reviewed. The main objective of this chapter is to introduce the reader to the latest results obtained in the literature regarding laser welding of these two light alloys, emphasising the most influential factors for each alloy. more...

Titanium alloys present excellent mechanical and corrosion properties, being widely employed in different industries such as medical, aerospace, automotive, petrochemical, nuclear and power generation, etc. Ti6Al4V is the α-β alloy most employed in industry. The modification of its properties can be achieved with convectional heat treatments and/or with laser processing. Laser remelting (LR) is a technology applied to Ti6Al4V by other authors with excimer and Nd-Yag laser with pure argon shielding gas to prevent risk of oxidation. In the present contribution, laser remelting has been applied for the first time to Ti6Al4V with a high power diode laser (with pure argon as shielding gas). Results showed that remelted samples (with medium energy densities) have higher microhardness and better corrosion resistance than Ti6Al4V base metal. more...

The application of laser beam welding to aluminum alloys has some complications, mainly due to their high reflectivity, high thermal conductivity and low viscosity. In order to increase the laser absorption of aluminum alloys, some surface treatments has been applied in the literature, such as the application of dark coatings or sandblasting. However, these conventional superficial treatments have some drawbacks, such as the low weld penetration, the possibility to undergo magnesium evaporation and the impossibility to control and/or change the superficial properties of the treated samples. In the present contribution, laser texturization treatments have been performed with a fibber laser for the first time on aluminum alloys to increase their weldability. These textured samples have shown better weldability than reference sandblasted samples. more...

To examine the predictive value of an early transcranial Doppler ultrasound (TCD) study performed in the emergency department in patients with spontaneous subarachoniod hemorrhage (SAH) in good neurological condition, in order to know which patients are at high risk of developing delayed cerebral ischemia (DCI).A descriptive observational study was carried out involving a period of 3 years.Critical Care and Emergency Department.The study consecutively included patients with SAH of grade I-III on the Hunt and Hess scale.DCI (decrease of 2 points in GCS or focal deficit), Mean Velocity (MV) of middle cerebral arteries (MCA), Lindegaard Index (IL). Sonographic vasospasm pattern (SVP) was considered if MCA-MV120cm/sc and IL3.The mean age of the 122 patients was 54.1±13.7 years; 57.3% were women. SVP was detected in 24 patients (19.7%), although high velocities patterns (HVP) were present in 38 patients (31.1%). DCI developed in 21 patients (MV183+/-49cm/sc), all with previous SVP. In this group MV increased 22+/-5cm/sc/day during the first 3 days. The group without HVP (84 patients/MV of 67+/-16.6cm/sc), compared with DCI group, showed differences in highest MV (p0.001), and also ΔMV/day (8.30+/-4,5cm/sc Vs 22+/-5cm/sc) during the first 3 days (p=0.009). In our series, ROC analysis selected the best cut-off value for ΔMV/day as 21cm/sc (p0.001).During the first 3 days, an increase of 21cm/s/24h in MCA-MV was associated with the development of symptomatic vasospasm. TCD is a useful tool for the early detection of patients at risk of DCI after SAH. more...

The presence of microorganisms with acquired resistance to multiple antibiotics complicates the management and outcome of critically ill patients. The intensivist, in his/her daily activity, is responsible for the prevention and control of the multiresistance and the challenge of prescribing the appropriate treatment in case of an infection by these microorganisms. We have reviewed the literature regarding the definition, important concepts related to transmission, recommendations on general measures of control in the units and treatment options. We also present data on the situation in our country known primarily through the ENVIN-UCI register. Addressing the multiresistance not only requires training but also teamwork with other specialists and adaptation to the local environment. more...

The spectrum of neuromuscular disease encountered in today's intensive care units (ICU) has evolved over the last few decades. However, in spite of many studies on neuromuscular disorders complicating critical illness as well as its epidemiology, etiology, treatment and prognosis, several key areas remain unclear. Two main groups are found among these neuromuscular abnormalities. The first group includes primary neuromuscular disorders present on admission to the ICU in which a possible etiology can be identified. Guillain-Barré syndrome and myasthenia gravis are two of the most common diseases admitted to ours units. In the second group, weakness is acquired in the ICU in the absence of preexisting neuromuscular disease. It is believed to reflect illnesses or treatments occurring in the ICU. Critical illness polyneuropathy (CIP) is the most clearly defined neuromuscular complication in this group. However, although we have better knowledge of its clinical, diagnosis, and prognosis features, its pathophysiological substrate has not been fully elucidated. Neuromuscular junction defects and specially myopathies, that frequently coexist with CIP, are the others main causes of acquired weakness in critically ill patients. Advances in understanding of these neuromuscular disorders could have an important impact in terms of developing effective preventive and therapeutic interventions that could help to improve the poor prognosis of these patients. more...

Two different genes encoding glutamine synthetase type I (GSI) and GSIII were identified in the genome sequence of R. albus 8. The identity of the GSIII protein was confirmed by the presence of its associated conserved motifs. The glnN gene, encoding the GSIII, was cloned and expressed in Escherichia coli BL21 cells. The recombinant protein was purified and subjected to biochemical and physical analyses. Subunit organization suggested a protein present in solution as both monomers and oligomers. Kinetic studies using the forward and the γ-glutamyl transferase (γ-GT) assays were carried out. Mutations that changed conserved glutamic acid residues to alanine in the four GSIII motifs resulted in drastic decreases in GS activity using both assays, except for an E380A mutation, which rather resulted in an increase in activity in the forward assay compared to the wild-type protein. Reduced GSIII activity was also exhibited by mutating, individually, two lysines (K308 and K318) located in the putative nucleotide-binding site to alanine. Most importantly, the presence of mRNA transcripts of the glnN gene in R. albus 8 cells grown under ammonia limiting conditions, whereas little or no transcript was detected in cells grown under ammonia sufficient conditions, suggested an important role for the GSIII in the nitrogen metabolism of R. albus 8. Furthermore, the mutational studies on the conserved GSIII motifs demonstrated, for the first time, their importance in the structure and/or function of a GSIII protein. more...

To determine the correlation between blood lactic acid levels in the first 48 hours and outcome, in hemodynamically stable patients, with moderate or severe head injury (HI), and to investigate the risk factors associated with abnormal lactate levels.A prospective observational study, in 210 adults patients with moderate or severe head injury. When the patients were hemodynamically stable, blood lactate concentrations were measured once on admission, twice daily during the first 2 days and once daily until lactate levels were normalized. The whole group 210 patients were divided into 2 groups. Group 1: (LA2.2 mmol/L) patients without occult hypoperfussion (OH), and group 2: (LAor= 2.2 mmol/L) patients with OH.One hundred and fifteen patients (57.76%) were categorized as group 1, and 95 patients (45.24%) as group 2. In the univariate analysis of risk factors for blood lactateor=2.2 mmol/L the following variables showed statistical significance: severity of the head injury measured by several scales [Glasgow Coma Scale (GCS), Injury Severity Score (ISS), Revised Trauma Score (RTS) and Acute Physiology and Chronic Health Evaluation (APACHE) II], arterial hypotension, hypoxemia, anaemia, hyperglucemia, hypothermia, a greater incidence of norepinephrine infusion, and the higher percentage of type II lesions in the head computerized tomography at admission showed in the group 1 (53.91% vs. 38.94%) (p0.03). In the multiple logistic regression analysis only two variables were risk independently associated with elevated blood lactate concentration: APACHE II in the first 24 hours: OR 1.12 (95% IC 1.06--1.196; p0.0001) and the first 48-hours total fluid infusion volumes: OR 1.09 (95% IC 1.021,16; p0.0001). The infection rate (63.2% vs 47.8%, p=0.026), and length of ICU stay [mediana (percentil 25--75)] [13.29 (7.11--21.22) days vs. 8.78 (4.40--16.72) days; p0.018] were significantly higher in patients with blood lactateor=2.2 mmol/L (group 2). Although, the percentage of intracranial hypertension and mortality was higher in the group 2, there was no significant difference. In the multivariate analysis, the increase of blood lactate concentration, was not independently associated as a risk factor with studied complications.The presence of OH in patients with moderate or severe head injury, with postres uscitation arterial pressure, according to present recommendations, is associated with a more severe head injury, showed by APACHE II and the total fluid infusion volumes in the first 48 hours. OH in head injury increases the infection rate and length of ICU stay. more...

Transcranial Doppler (TCD) constitutes a valuable method for managing acute/critical neurological patients and it would therefore be interesting to reduce, as far as possible, the complexity involved in interpreting its findings.The Objective of this study was to design and validate a correlation diagram of the echographic patterns and acute haemodynamic situations in the brain that makes it easier to teach and optimises the effectiveness of TCD as a diagnostic aid.A diagram that represents the average speed and pulsatility index on a system of coordinates. Five fundamental echographic patterns were identified and the most frequent acute cerebral haemodynamic situations are detailed for each of them. The value of the diagram was tested in resident doctors with varying degrees of knowledge of TCD. In the first phase with no diagram (evaluation A), the interpretation of the TCD and diagnosis of the haemodynamic situation in the brain were evaluated in nine clinical cases. In the second phase, with a diagram (evaluation B), they were asked to draw up new reports on the same cases. We compared the number of times they were right in the two evaluations.A total of 216 echographic reports were obtained. The mean number of correct answers in evaluation A was 2, interquartile range (0.25 3.75). In evaluation B the number of correct answers rose to 4 (3.25 6.75) (p= 0.005). Using the diagram increased the diagnostic capacity of all the residents, but especially so in those with less training.Use of the diagram makes it easier for people who are not experts to learn to interpret TCD findings in acute/critical neurological situations. more...

Two techniques to reduce the contact resistance RC in AlGaN/GaN HFETs have been investigated. Both techniques involve the formation of a matrix of 100 nm diameter pinholes in resist in the contact region using e-beam direct-write lithography. In the first technique, silicon is implanted through the matrix to form doped/damaged filaments extending through the AlGaN cap to the 2DEG. In the second technique, sputtering is used to remove the AlGaN from the pinhole, allowing metal to directly contact the 2DEG. RC was measured as a function of anneal temperature. Si implanted samples gave RC = 0.34 Ωmm for 800 °C annealing, roughly half the value of control samples. Sputter etch samples had RC comparable to that of controls. more...