13 research outputs found

    Assessment of the functional properties stability in (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 piezoceramics: huge dielectric and piezoelectric nonlinearity

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    The (Ba,Ca)(Zr,Ti)O3 ceramic system has received special attention in recent years because it may lead to promising lead-free piezoceramics. However, the stability of the functional properties of these materials is an important issue that requires greater attention. In this work, the (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 compound (BCZT) is taken as a reference material for evaluating the variation of the functional properties when an external stimulus (e.g., electric field or dynamical stress) is applied, which may constitute an important drawback of piezoceramics. The results show that BCZT exhibits a huge nonlinear behavior, which notably limits this lead-free material for transfer to applications. The instabilities manifest at considerably low amplitudes of the applied electric field or dynamical stress due to a large extrinsic contribution from the irreversible motion of domain walls. Understanding and controlling the physical phenomena related to the domain wall motion presents a fundamental challenge for achieving an effective enhancement of the functional property stability of this system.Postprint (author's final draft

    Perfusion Decellularization of Extrahepatic Bile Duct Allows Tissue-Engineered Scaffold Generation by Preserving Matrix Architecture and Cytocompatibility

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    Reconstruction of bile ducts damaged remains a vexing medical problem. Surgeons have few options when it comes to a long segment reconstruction of the bile duct. Biological scaffolds of decellularized biliary origin may offer an approach to support the replace of bile ducts. Our objective was to obtain an extracellular matrix scaffold derived from porcine extrahepatic bile ducts (dECM-BD) and to analyze its biological and biochemical properties. The efficiency of the tailored perfusion decellularization process was assessed through histology stainings. Results from 4’-6-diamidino-2-phenylindole (DAPI), Hematoxylin and Eosin (H&E) stainings, and deoxyribonucleic acid (DNA) quantification showed proper extracellular matrix (ECM) decellularization with an effectiveness of 98%. Immunohistochemistry results indicate an effective decrease in immunogenic marker as human leukocyte antigens (HLA-A) and Cytokeratin 7 (CK7) proteins. The ECM of the bile duct was preserved according to Masson and Herovici stainings. Data derived from scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) showed the preservation of the dECM-BD hierarchical structures. Cytotoxicity of dECM-BD was null, with cells able to infiltrate the scaffold. In this work, we standardized a decellularization method that allows one to obtain a natural bile duct scaffold with hierarchical ultrastructure preservation and adequate cytocompatibility

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

    Inducción de resistencia a Mycosphaerella fijiensis Morelet y su relación con el rendimiento de plantas de banano (Musa AAA) CV. Williams

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    Bananas are widely grown in Ecuador, being the most exported crop, however, fruit production is reduced by phytosanitary diseases such as black Sigatoka. Management of this disease includes mostly chemical synthesis fungicides that contribute to environmental pollution.  For this reason, this experiment was carried out in the central zone of the ecuadorian coastal region, to evaluate at field level the effect of inducing resistance substances against the evolution of  “black Sigatoka” in the dry and rainy seasons. The experiment was deployed in a complete randomized block design, with five treatments and 4 blocks. The treatments studied were T1: Jasmonic acid, T2: Salicylic acid, T3: Carophilaceas extract, plus chemical (T4) and absolute (T5) controls. The infection rate, leaf area and functional leaves were measured at both, flowering and harvest stages. Additionally, net bunch weight was also evaluated. Jasmonic and salicylic acid showed a negative effect on the infection rate in both production periods. In terms of net bunch weight, Salicylic Acid registered the best average, compared to other treatments. Finally, this experiment showed that these resistance inducers can be implemented in disease management programs, as well as to increase crop yield, thus reducing the use of chemical products whose indiscriminate use creates resistance and environmental contamination.El banano es ampliamente sembrado en el Ecuador, siendo el producto agrícola más exportado, sin embargo, la producción de la fruta se ve reducida por enfermedades fitosanitarias como la sigatoka negra. Su modo de control principalmente incluye fungicidas de síntesis química que contribuyen a la contaminación del medio ambiente.  Por esta razón, se realiza el presente experimento en la zona central del litoral ecuatoriano, cuyo objetivo fue evaluar a nivel de campo, el efecto de sustancias inductoras de resistencia frente a la evolución de la enfermedad de la Sigatoka negra en las épocas seca y lluviosa. El experimento se planteó bajo un diseño de bloques aleatorizado, de 5 tratamientos y 4 bloques. Los tratamientos estudiados fueron T1: ácido jasmónico, T2: ácido salicílico, T3: extracto de carophilaceas, más dos testigos, químico (T4) y absoluto (T5). Se midió el índice de infección, área foliar y hojas funcionales, tanto a la floración como a la cosecha. Adicionalmente se evaluó también el peso neto del racimo. Ácido jasmónico y salicílico, mostraron efecto sobre el índice de infección, en las dos épocas de producción estudiadas. En cuanto al peso neto del racimo, ácido salicílico, registró el mejor promedio, en comparación con los otros tratamientos. Finalmente, con este experimento se demostró que estos inductores de resistencia pueden ser implementados en programas de manejo de la enfermedad, así como también para aumentar el rendimiento del cultivo, reduciendo de esta manera el uso de productos químicos cuyo uso indiscriminado crea resistencia y contaminación ambiental

    Prevalence and risk factors for Enterobacteriaceae in patients hospitalized with community-acquired pneumonia

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    Background and objective Enterobacteriaceae (EB) spp. family is known to include potentially multidrug-resistant (MDR) microorganisms, and remains as an important cause of community-acquired pneumonia (CAP) associated with high mortality. The aim of this study was to determine the prevalence and specific risk factors associated with EB and MDR-EB in a cohort of hospitalized adults with CAP. Methods We performed a multinational, point-prevalence study of adult patients hospitalized with CAP. MDR-EB was defined when >= 3 antimicrobial classes were identified as non-susceptible. Risk factors assessment was also performed for patients with EB and MDR-EB infection. Results Of the 3193 patients enrolled with CAP, 197 (6%) had a positive culture with EB. Fifty-one percent (n = 100) of EB were resistant to at least one antibiotic and 19% (n = 38) had MDR-EB. The most commonly EB identified were Klebsiella pneumoniae (n = 111, 56%) and Escherichia coli (n = 56, 28%). The risk factors that were independently associated with EB CAP were male gender, severe CAP, underweight (body mass index (BMI) < 18.5) and prior extended-spectrum beta-lactamase (ESBL) infection. Additionally, prior ESBL infection, being underweight, cardiovascular diseases and hospitalization in the last 12 months were independently associated with MDR-EB CAP. Conclusion This study of adults hospitalized with CAP found a prevalence of EB of 6% and MDR-EB of 1.2%, respectively. The presence of specific risk factors, such as prior ESBL infection and being underweight, should raise the clinical suspicion for EB and MDR-EB in patients hospitalized with CAP
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