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A new two-step densification method for wooden materials entitled hot isostatic pressing (HIP) is proposed. This method has the advantage over previous densification methods that can achieved almost the full densification of wood, reaching values up to 1.47 kg/m3, which exceeds any value ever reported for a hardwood species. Furthermore, it can preserve about 35% of the original volume, in comparison to other methods which typically can preserve only 20% of the volume. Although not tested in this investigation, in principle, the HIP method should be capable of densifying any shape of wood including circular and tubular cross sections because the main densification mechanism is based on gas pressure that is equally exerted in the entire surface, rather than localized mechanical compression, which can only be effective with rectangular cross sections. In the first stage of the two-step proposed method, the compressive strength of the anatomical wood structure is reduced by delignification, and, in the second, a full densification is achieved by hot isostatic pressing under argon atmosphere. Three tropical hardwood species with distinct anatomical characteristics and properties were used to test the method. The HIP-densified wood's microstructural, chemical, physical, and mechanical properties were assessed. Apart from the high densification values and volume preservation, the results indicate that proposed method was effective for all the tested species, showing homogenous density patterns, stable densification without noticeable shape recovery, and enhanced mechanical properties. Future research should test the HIP method in softwoods and consider the ring orientation in order to enhance the control of the densified geometry.
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Capillary diffraction or microdiffraction are standard techniques for characterizing small samples when only a few milligrams are available. On the other hand, we have typical grazing incidence diffraction or different variations of grazing incidence (GI) diffraction used, such as in-plane grazing incidence (IP-GI) or GI using a micro focusing source, to study thin films. However, when few powder micrograms are available, the characterization task is complicated. In the present work, few micrograms of typical forensic samples are analyzed using standard Bragg-Brentano, X-ray powder diffraction geometry, and grazing incidence X-ray micro-diffraction (GIµXRD). Samples include soils, cosmetic eyeshadows, two different pyrotechnic materials, and a highly explosive mixture contained at primer cup of ammunition. The analysis was carried out from 1 to 5 degrees of the incident parallel beam with a shaking sample. Depending on the fixed incident angle, different small regions of the diffraction patterns showed an improvement in the intensity of the peaks with respect to the conventional Bragg-Brentano configuration. However, 3-5 degrees of the fixed incident beam showed the best results. This new data acquisition technique, based on the combination of two known diffraction methods, could be a powerful tool for studying samples outside of forensic sciences such as nanomaterials, medicine, or any other field where the sample quantity is extremely small, also, without the need to transport evidence and travel to external facilities with higher analytical performance such as synchrotron radiation installations or other large experimental facilities.
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Resumen En estudios previos se ha demostrado que la endotoxemia inducida por lipopolisacárido (LPS) produce un desacoplamiento cardiorrespiratorio (CRP) debido a los efectos fisiológicos de la inflamación sistémica. Adicionalmente se sabe que la oxitocina tiene efectos antiinflamatorios y propiedades cardioprotectoras; sin embargo, se desconoce si ésta modifica el acoplamiento CRP. El objetivo del presente estudio fue comparar diferentes métodos matemáticos lineales y no lineales para la detección del desacoplamiento cardiorrespiratorio entre series de tiempo cardiacas y respiratorias. Se estudiaron series de tiempo R-R obtenidas de electrocardiogramas de grupos de roedores macho a los cuales se les administró solución salina o vehículo (V); lipopolisacárido (LPS); oxitocina (O) y LPS + oxitocina (LPS+Ox). Las series R-R y respiratorias derivadas del electrocardiograma (EDR) se analizaron en conjunto para cuantificar su grado de acoplamiento a través de las técnicas de correlación cruzada; entropía muestral cruzada; entropía condicional; información mutua; e información mutua de Rényi para los cuatro grupos. Se observó que la oxitocina no parece favorecer el acoplamiento CRP durante la endotoxemia inducida por LPS. Finalmente, se encontró que la entropía muestral cruzada y la entropía condicional presentaron las mayores diferencias estadísticas para identificar el desacoplamiento CRP producido por el LPS.
Abstract Previous studies have shown that LPS-induced endotoxemia causes a cardiorespiratory (CRP) uncoupling owing to the physiological effects of systemic inflammation. Also, it is known that oxytocin has anti-inflammatory effects and cardioprotective properties; however, it is unknown whether it can modify the CRP coupling. This study aimed to compare different linear and nonlinear mathematics methods for the detection of cardiorespiratory uncoupling between cardiac and respiratory time series. The R-R time series of electrocardiograms of male rodents that were administered with saline solution (V); lipopolysaccharide (LPS); oxytocin (O) and LPS + oxytocin (LPS + Ox) were studied. We tested the R-R and respiratory series derived from the electrocardiogram (EDR) for the four groups to quantify the degree of coupling with cross-correlation; cross sample entropy; conditional entropy; mutual information; and Rényi's mutual information. We found that oxytocin does not seem to favor the CRP coupling during endotoxemia induced by LPS. Finally, we observed that the cross-sample entropy and the conditional entropy presented the highest statistical differences to identify the CRP uncoupling produced by LPS.
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Bacterial resistance is a growing problem worldwide and is estimated that deaths by infectious diseases associated with resistant pathogens will generate 10 million deaths per year in 2050. This problem becomes more serious due to the low level of research and development of new drugs, which has fallen drastically in the last 40 years. For example, in the last decade of a total of 293 new drugs approved by the FDA, only 9 corresponded to antimicrobial drugs and none constituted a new structural class. The majority of the molecules in the clinical phase II or III, coming from modifications of drugs in clinical use, this strategy makes easier the bacterial susceptibility to generate resistance through the mechanisms expressed for their drug predecessors. Under this scenario, it is urgent to generate the most novel strategies for the development of antibacterial compounds with new targets or mechanism of action, without a structural relationship with the antibiotic drugs predecessors. Under this look, the present review addresses the development of the latest antibacterial drugs in clinical phases II and III, analyzing the design strategies by which these new molecules were obtained and the structure-activity relationship of these new families of antibiotics, in order to define the state of the vanguard antibacterial drugs in the post-antibiotic era.
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Antibacterianos/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla , Animais , Humanos , Relação Estrutura-AtividadeRESUMO
Introducción: Existen varias curaciones para quemaduras. La sulfadiazina de plata se ha usado por años pero las membranas microporosas son cada vez más preferidas. Objetivos: Comparar la eficiencia de las membrana microporosa (Telfa Clear®) versus sulfadiazina de plata (Platsul®) en menores de 15 años hospitalizados por quemadura. Pacientes y Métodos: Estudio de cohorte retrospectivo de 87 pacientes, dividido en 2 grupos comparables en extensión y profundidad de la quemadura, edad y sexo. Durante enero a diciembre 2007 se curaron 52 pacientes con Platsul® y desde enero a octubre 2008 se curaron 35 con Telfa Clear®. Se evalúa tiempos y extensión de reepitelización, porcentaje de injertos, costos, días de hospitalización, número de curaciones, complicaciones, almacenamiento-estabilidad y costos. Estadística no paramétrica para el análisis univariado y regresión logística multivariado en Stata 11.2. Resultados: Los pacientes curados con Platsul® se injertaron más tardíamente y presentan más curaciones. Platsul® es peor evaluado por su almacenamiento-estabilidad y mayores costos. No hay diferencia en la incidencia de infección. Conclusiones: Ambas Técnicas son eficientes en permitir reepitelización, pero Platsul® puede demorar el injerto. La Telfa Clear® es mejor evaluado por el equipo de salud en cuanto a almacenamiento y estabilidad. El menor costo de Telfa Clear® es una ventaja.
Introduction: There are several dressings for burns. Silver sulfadiazine has been used for years but microporous membranes are increasingly preferred. Objectives: To compare the efficiency of microporous membrane (Telfa Clear®) versus silver sulfadiazine (Platsul®) in children younger than 15 years old hospitalized for burns. Patients and Methodology: Retrospective cohort study of 87 patients, divided into 2 comparable groups in extent and depth of the burn, age and sex. During January to December 2007, in 52 patients Platsul® were use and in 35 patients Telfa Clear® were use from January to October 2008. The time and extent of re-epithelialization, percentage of grafts, costs, length of stay, number of dressing change, complications, storage-stability and costs are evaluated. Non-parametric statistics were used for univariate analysis and logistic regression for multivariate analysis en Stata 11.2. Results: Platsul® was associate to a later graft and had a greater number of dressing changes. Platsul® is worst rated for its storage-stability and higher costs. No difference in infection rate was observed. Conclusions: Both techniques are efficient in allowing re-epithelialization, but burns treated with Platsul® were grafted later than when Telfa Clear® was used. Telfa Clear® is best evaluated by the health team in terms of storage and stability. The cost of Telfa Clear® is presented as an advantage.
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Humanos , Masculino , Feminino , Lactente , Pré-Escolar , Criança , Sulfadiazina de Prata/uso terapêutico , Bandagens , Queimaduras/terapia , Anti-Infecciosos Locais/uso terapêutico , Estudos Retrospectivos , Resultado do Tratamento , ReepitelizaçãoRESUMO
While 2-amino-4-(4-chlorophenyl)thiazole (AT) drug and thiazole derivatives have several biological applications, these compounds present some drawbacks, such as low aqueous solubility and instability. A new complex of ßCD-AT has been synthesized to increase AT solubility and has been used as a substrate for the deposit of solid-state AuNPs via magnetron sputtering, thus forming the ßCD-AT-AuNPs ternary system, which is stable in solution. Complex formation has been confirmed through powder X-ray diffraction and 1D and 2D nuclear magnetic resonance. Importantly, the amine and sulfide groups of AT remained exposed and can interact with the surfaces of the AuNPs. The complex association constant (970 M-1) has been determined using phase solubility analysis. AuNPs formation (32 nm average diameter) has been studied by UV-Visible spectroscopy, transmission/scanning electron microscopy and energy-dispersive X-ray analysis. The in vitro permeability assays show that effective permeability of AT increased using ßCD. In contrast, the ternary system did not have the capacity to diffuse through the membrane. Nevertheless, the antibacterial assays have demonstrated that AT is transferred from ßCD-AT-AuNPs, being available to exert its antibacterial activity. In conclusion, this novel ßCD-AT-AuNPs ternary system is a promising alternative to improve the delivery of AT drugs in therapy.
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Ouro/química , Nanopartículas Metálicas/química , Preparações Farmacêuticas/metabolismo , Tiazóis/química , beta-Ciclodextrinas/química , Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Transporte Biológico , Cristalização , Nanopartículas Metálicas/ultraestrutura , Testes de Sensibilidade Microbiana , Permeabilidade , Pós , Espectroscopia de Prótons por Ressonância Magnética , Solubilidade , Soluções , Espectrometria por Raios X , Tiazóis/farmacologia , Difração de Raios X , beta-Ciclodextrinas/farmacologiaRESUMO
Zika virus (ZIKV) is an emerging mosquito-borne flavivirus circulating in Asia and Africa. In 2013, a large outbreak was reported on the archipelago of French Polynesia. In this study, we report the detection and molecular characterization of Zika virus for the first time in Chile from an outbreak among the inhabitants of Easter Island. A total of 89 samples from patients suspected of having ZIKV infection were collected between the period from January to May, 2014. Molecular diagnosis of the virus was performed by RT-PCR followed by the sequencing of the region containing the NS5 gene. A comparison of the viral nucleic acid sequence with those of other strains of ZIKA virus was performed using the MEGA software. Fifty-one samples were found positive for ZIKV by RT-PCR analysis. Further analysis of the NS5 gene revealed that the ZIKV strains identified in Easter Island were most closely related to those found in French Polynesia (99.8 to 99.9% nt and 100% aa sequence identity). These results strongly suggest that the transmission pathway leading to the introduction of Zika virus on Easter Island has its origin in French Polynesia.
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Surtos de Doenças , Infecção por Zika virus/epidemiologia , Zika virus/isolamento & purificação , Análise por Conglomerados , Humanos , Epidemiologia Molecular , Filogenia , Polinésia/epidemiologia , RNA Viral/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Homologia de Sequência , Zika virus/classificação , Zika virus/genéticaRESUMO
Clostridium difficile infection has gained importance in recent years as a result of the rapid spread of epidemic strains, including hypervirulent strains. This study reports the molecular epidemiology of C. difficile obtained from hospitalized patients in Chile. Seven hundred and nineteen isolates of toxigenic C. difficile from 45 hospitals across the country were characterized through toxin profile, pulsed-field gel electrophoresis (PFGE), and sequencing of the tcdC gene. In addition, polymerase chain reaction (PCR) ribotyping and multilocus sequence typing (MLST) were performed on a subset of selected strains. PFGE typing of 719 isolates of C. difficile produced 60 PFGE patterns (subtypes). Subtype 1 was predominant (79% of isolates) and related to the hypervirulent strain (NAP1). Subtype 1 showed 73% relatedness with nine other subtypes, which had a similar tcdC deletion. Subtype 1 corresponded to ribotype 027 and ST1. This report shows the wide dissemination of the hypervirulent strain NAP1/027/ST1 in Chile.
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Clostridioides difficile/isolamento & purificação , Infecções por Clostridium/epidemiologia , Infecções por Clostridium/microbiologia , Epidemias , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Toxinas Bacterianas/genética , Criança , Pré-Escolar , Chile/epidemiologia , Clostridioides difficile/classificação , Clostridioides difficile/genética , Análise por Conglomerados , Eletroforese em Gel de Campo Pulsado , Feminino , Genótipo , Hospitais , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Tipagem de Sequências Multilocus , Ribotipagem , Adulto JovemRESUMO
Entre 1985 y 1989 tratamos a doce pacientes con traumatismo grave de extremidades por proyectiles de alta velocidad, la mayoría de ellos, producto de entrenamiento militar. Nueve de ellos presentaron compromiso de las extremidades inferiores. La lesión vascular se acompañó de lesión ósea y de partes blandas en todos los casos. La conducta terapéutica fue fijación de la extremidad por medio de tutores externos, la reparación arterial con resección y anastomósis término terminal, o bien injerto de vena safena o PTFE, este último en cinco casos. Venorrafia se efectúa en cinco casos. La cobertura de partes blandas se hizo con rotación de colgajo cutáneo (cuatro casos), injerto de latissimus dorsi utilizando anastomosis vascular con técnica microquirúrgica en una ocasión y en siete con injerto cutáneo fenestrado. Se obtuvo recuperación funcional completa de diez pacientes y en sólo una de la serie se debió recurrir a una amputación mayor por fracaso de la revascularización e infección
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Humanos , Masculino , Adulto , Traumatismos do Braço , Ferimentos por Arma de Fogo , Traumatismos da Perna , Procedimentos Cirúrgicos VascularesRESUMO
Blood pressure, weight, height and cardiovascular risk factors were evaluated in 73 adults of Easter Island (mean age 49 +/- 12.9 (SD) years) in January 1989 and 1990. Their mean blood pressure (BP) was 129 +/- 24/81 +/- 14, significantly higher by 7/5 mm Hg than in 1979 (p < 0.05). Of the population studied 30% of subjects were hypertensives. Both systolic (S) and diastolic blood pressure (DBP) correlated with age (r = 0.40, p < 0.005 and r = 24, p < 0.05 respectively). In males body mass index correlated strongly with SBP and DBP (r = 0.55, p < 0.005 and r = 0.52, p < 0.01). Forty eight % of subjects were obese, 60% smoked (14 cigarettes/day), 38% drank alcohol and 70% lead sedentary lives; their level of stress was considered average. In 23 normotensives or undiagnosed hypertensives 24 hour urine was collected for sodium, potassium, creatinine and kallikrein; mean urinary sodium excretion was 121 +/- 39 mmol/day; potassium excretion 59 +/- 29 mmol/day, creatinine excretion 1383 +/- 489 mg/day and kallikrein excretion 682 +/- 355 mU/day; of these, only urinary sodium was significantly lower than values determined in a group of 29 continental volunteers. Eleven natives that had never left the island had similar BP and risk factors than a sex and age paired sample, who has spent 10.9 +/- 7.8 years in the continent. The present study demonstrates that Easter Island natives have increased their mean BP in 10 years, elevated their BP with age and have lost the protection previously associated to staying in the island.(ABSTRACT TRUNCATED AT 250 WORDS)
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Hipertensão/epidemiologia , Havaiano Nativo ou Outro Ilhéu do Pacífico , Adulto , Fatores Etários , Chile/epidemiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Havaiano Nativo ou Outro Ilhéu do Pacífico/estatística & dados numéricos , Polinésia/epidemiologia , Fatores de Risco , Fatores SexuaisRESUMO
This study was conducted to evaluate usefulness of the physiologic stability index (PSI) in a pediatric intensive care Unit (PICU) of a University based hospital at Santiago, Chile. Subjects include all patients (n = 152) consecutively admitted to our PICU between april 1987 and august 1988. The PSI system was applied during the first four days from admission. The age of the patients ranged from 10 days to 15 years. Scores obtained from survivors and non survivors were compared using an analysis of variance. For maximum PSI, survivors had significantly lower scores (9.39 points) that non survivors (21.71 points). Multiple logistic regression was used to display associations between mean obtained scores and probability of death and a curve was plotted which is similar to that obtained in previous experiences from other countries.