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The combustion of pure H2 in engines is still troublesome, needing further research and development. Using H2 and diesel in a dual-fuel compression ignition engine appears as a more feasible approach. Here we report an experimental assessment of performance and emissions for a single-cylinder, four-stroke, air-cooled compression ignition engine operating with neat diesel and H2-diesel dual-fuel. Previous studies typically show the performance and emissions for a specific operation condition (i.e. a fixed engine speed and torque) or a limited operating range. Our experiments covered engine speeds of 3000 and 3600 rpm and torque levels of 3 and 7 Nm. An in-house designed and built alkaline cell generated the H2 used for the partial substitution of diesel. Compared with neat diesel, the results indicate that adding H2 decreased the air-fuel equivalence ratio and the Brake Specific Diesel Fuel Consumption Efficiency by around 14-29 % and 4-31 %. In contrast, adding H2 increased the Brake Fuel Conversion Efficiency by around 3-36 %. In addition, the Brake Thermal Efficiency increased in the presence of H2 in the range of 3-37 % for the lower engine speed and 27-43 % for the higher engine speed compared with neat diesel. The dual-fuel mode resulted in lower CO and CO2 emissions for the same power output. The emissions of hydrocarbons decreased with H2 addition, except for the lower engine speed and the higher torque. However, the dual-fuel operation resulted in higher NOx emissions than neat diesel, with 2-6 % and 19-48 % increments for the lower and higher engine speeds. H2 emerges as a versatile energy carrier with the potential to tackle current energy and emissions challenges; however, the dual-fuel strategy requires careful management of NOx emissions.
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Improving the thermal efficiency of internal combustion engines is essential to reduce the operating costs and complaints with the increasing environmental requirements. Thermoelectric generators came up as an opportunity to reuse part of the heat loss with the exhausts. This paper evaluates the performance of a thermoelectric generator to improve the efficiency of a stationary diesel engine under different rotational speeds and torques. The data was obtained through CFD simulations and validated with experiments. The proposed solution uses a cooling system to control the temperature of the thermoelectric modules. The results show that the torque and the rotational speed of the engine are the most significant performance parameters of the thermoelectric generator, while the influence of the cooling water temperature has a minor but still significant influence. Additionally, the results show a change from 1.3% to 6.2% in the thermoelectric generator efficiency, while the exergy efficiency varies between 1.8% and 7.9%. The exergy balance indicates that most of the exergy is loss because of the irreversibilities in the thermoelectric generator and of the exergy loss with the exhausts. The exergy loss can be reduced by optimizing the design of the heat exchanger. Since the thermoelectric generator improved the engine efficiency by a marginal 0.2%-0.8%. Therefore, it is important to further research how to improve the design of heat exchangers for thermoelectric generators to increase their energy conversion efficiency and their impact on the energy efficiency of internal combustion engines.
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RESUMEN El objetivo de esta investigación es determinar los valores de velocidad de corte, avance y trayectoria (estrategia de mecanizado) en el mecanizado del PEEK que permitan obtener una rugosidad (Ra) recomendada según la literatura para la adecuada diferenciación, proliferación y adhesión de células mesenquimales aplicables en implantes óseos[3,4,6,7,11]. De la revisión del estado del arte se determinó que dichos procesos celulares se obtienen cuando la rugosidad superficial Ra tiene un valor entre 1 μm a 3 μm[9,12], de igual forma, a mayor anisotropía superficial, mayor diferenciación celular se obtendrá[7,8]. Para determinar los parámetros de corte con los que se obtiene una rugosidad Ra óptima se realizó un diseño experimental de superficie de respuesta con rangos de exploración de: velocidad de corte: 60 m/min - 90 m/min y velocidad de avance: 900 mm/min - 1500 mm/min usados para ambas estrategias evaluadas: Raster y Espiral. La investigación concluyó que los parámetros de mecanizado con los cuales se obtiene una rugosidad recomendada Ra para la elaboración de implantes óseos son: velocidad de avance 1500 mm/min y velocidad de corte de 90 m/min mecanizando con una trayectoria (técnica de mecanizado) Raster, con la cual se obtiene una rugosidad Ra de 2,7 μm.
ABSTRACT The objective of this study is determinate the values of cutting speed, feed along and the machining strategy to get optimal values of roughness Ra for the machining of PEEK, polyetheretherketone, to get to get differentiation, proliferation and adhesion for mesenchymal for the development of individualized tailored prosthesis. According to literature to get those cellular process the superficial roughness must have a value Ra of 1 μm to 3 μm, also, if more anisotropic surface, more adhesion of cells. To determinate the recommended roughness Response Surface Methodology was used, the region of operability was: cutting speed 60 m/min to 90 m/min, feed along 900 mm/min to 1500 mm/min and a cutting strategy of Raster and Spiral. In this investigation the conclusion was that the cutting parameter to get the recommended roughness Ra for the elaboration of tailored prosthesis is feed along of 1500 mm/min and cutting speed of 90 m/min, machining with Raster strategy, for those parameters the roughness was of 2,7 μm.
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El Virus de la Hepatitis E (VHE) es uno de los agentes causales de enfermedad hepática aguda en humanos, aunque también puede inducir hepatitis crónica en pacientes inmunocomprometidos. Existen cuatro genotipos que generan enfermedad en humanos: los genotipos 1 y 2 asociados con brotes epidémicos por consumo de aguas contaminadas y los genotipos 3 y 4 de trasmisión zoonótica, implicados en brotes esporádicos en países desarrollados donde el cerdo es el principal reservorio. En Colombia existe evidencia serológica de la infección en humanos y cerdos: se ha detectado el genoma viral en hígados de cerdos en plantas de beneficio y expendios de carne; sin embargo no se conoce lo suficiente sobre la infección en el país. Con el fin de determinar si los cerdos del departamento de Antioquia (Colombia) están excretando VHE en la edad del beneficio, se obtuvieron 152 muestras de heces de cerdos en cinco plantas de beneficio de distintas regiones del departamento en las que se determinó la presencia del genoma viral por medio RT-PCR. El porcentaje de positividad hallado fue del 26.9% (41/152); se encontró, además, que los cerdos que provenían de las subregiones Norte y Oriente de Antioquia tuvieron el menor (11.6%) y mayor (58.3%) porcentaje de muestras positivas, respectivamente. Estos resultados indican que los cerdos en el momento de sacrificio están excretando el virus a través de sus heces y que el VHE está circulando en las diferentes subregiones del departamento.
The Hepatitis E Virus (HEV) is one of the causative agents of acute liver disease in humans, although it can also lead to chronic hepatitis in immunocompromised patients. There are four genotypes that generate human disease: genotypes 1 and 2, associated with outbreaks due to consumption of contaminated waters, and genotypes 3 and 4 by zoonotic transmission, implicated in sporadic outbreaks in developed countries, where pigs are the main reservoir. In Colombia there is serological evidence of infection in humans and pigs: the viral genome has been detected in livers of pigs at slaughterhouses and butcher shops; however is not enough known about the infection in the country. In order to find out whether pigs in Antioquia (Colombia) are excreting the virus, the presence of the viral genome by RT-PCR was determined in 152 samples of pig feces obtained at five slaughterhouses of Antioquia, which came from different regions of the department. The percentage of positivity was 26.9% (41/152) and pigs that came from the North and East subregions of Antioquia had the lowest (11.6%) and higher (58.3%) percentage of positive samples, respectively. These results indicate that pigs at slaughter age are excreting the virus in their feces and that HEV is circulating in different subregions of the department.
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BACKGROUND: The success rates of therapies for treating Helicobacter pylori vary greatly worldwide and the ideal treatment has yet to be clearly established. AIMS: A systematic review was carried out to evaluate the effectiveness of current first and second-line therapies in treating H.pylori infection. METHODS: Two researchers independently carried out Internet search engine reviews (PUBMED, EMBASE, MEDLINE) of clinical trials on adults published between 1990 and 2012 in both English and Spanish. RESULTS: Forty-three (n=8,123) clinical trials were evaluated that included first and second-line triple, quadruple, and sequential therapies. The eradication rates of the standard triple therapy are unacceptable (≤80%) in countries where H.pylori is highly resistant to clarithromycin and metronidazole. Administration of the standard triple therapy for more than 7 days does not improve its effectiveness. No statistically significant differences were observed between the eradication rates of the quadruple therapy with bismuth and the standard triple therapy. Even though the sequential and concomitant therapies are equally successful regimens, the triple therapy with levofloxacin offers the best results as first and second-line treatment, but quinolone resistance can diminish its effectiveness. The triple therapy with levofloxacin and the sequential and concomitant treatments were superior to the standard triple regimen as first-line therapy. CONCLUSIONS: Currently there is no ideal first or second-line treatment for achieving 100% eradication. The therapeutic order should be carried out according to the initial treatment and local antimicrobial resistance studies.
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Antibacterianos/uso terapêutico , Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori , Infecções por Helicobacter/microbiologia , Humanos , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
BACKGROUND: Success in H. pylori eradication with conventional therapies has decreased to unacceptable levels (≤80%). New schemes of combined treatment are currently needed. AIM: To test a miscellaneous therapy for H. pylori eradication. METHODS/PATIENTS: Open-label, pilot, single-centre and prospective study. Patients received a 15-day treatment scheme that consisted of 5 initial days of lansoprazole 30 mg b.d., amoxicillin 1 g b.d., and metronidazole 500 mg t.d.s.; days 6 to 10: lansoprazole 30 mg q.d.s. and metronidazole 500 mg t.d.s.; days 11 to 15: lansoprazole 30 mg b.d., clarithromycin 500 mg b.d. and metronidazole 500 mg t.d.s. Each patient underwent an upper endoscopy before treatment and a second follow-up endoscopy at least 4 weeks after therapy. Success was defined on the basis of an eradication rate following a per-protocol analysis ≥95%. Biopsies before and after therapy were obtained for histological evaluation and rapid urease test. RESULTS: One hundred and twenty-two patients were enrolled and 118 patients completed the study. The eradication rate for H. pylori with miscellaneous therapy was 94% (confidence Interval (CI) 95%, 90-98.3%) in the per-protocol analysis (PP) and 91% (95% CI, 86-96%) in the intention-to-treat (ITT) analysis. Adherence to treatment was 96% (113 patients). Among patients who completed treatment, 55% presented adverse events, mainly nausea and abdominal pain. CONCLUSION: A miscellaneous therapy, based on the combination of multiple medications in high doses for 2 weeks, and with gastric pH elevation, is a highly effective treatment as a first-line therapy for the eradication of H. pylori.
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Antibacterianos/uso terapêutico , Gastrite/tratamento farmacológico , Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori/efeitos dos fármacos , Úlcera Péptica/tratamento farmacológico , Inibidores da Bomba de Prótons/uso terapêutico , Adulto , Amoxicilina/uso terapêutico , Claritromicina/uso terapêutico , Quimioterapia Combinada/métodos , Feminino , Determinação da Acidez Gástrica , Gastrite/microbiologia , Gastroscopia , Infecções por Helicobacter/microbiologia , Helicobacter pylori/isolamento & purificação , Humanos , Concentração de Íons de Hidrogênio , Lansoprazol/uso terapêutico , Masculino , Metronidazol/uso terapêutico , Pessoa de Meia-Idade , Úlcera Péptica/microbiologia , Projetos Piloto , Estudos Prospectivos , Inquéritos e Questionários , Resultado do TratamentoRESUMO
Forty-seven plant extracts of 10 species of the genus Euphorbia (Euphorbiaceae) used by Colombian traditional healers for the treatment of ulcers, cancers, tumors, warts, and other diseases, were tested in vitro for their potential antitumour (antiproliferative and cytotoxic) and antiherpetic activity. To evaluate the capacity of the extracts to inhibit the lytic activity of herpes simplex virus type 2 (HSV-2) and the reduction of viability of infected or uninfected cell cultures, the end-point titration technique (EPTT) and the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] colorimetric assay were used, respectively. The therapeutic index of the positive extracts for the antiviral activity was determined by calculating the ratio CC50 (50% cytotoxic concentration) over IC50 (50% inhibitory concentration of the viral effect). Five of the 47 extracts (11%) representing 3 out of 10 Euphorbia species (30%) exhibited antiherpetic action; the highest activity was found in the leaf/stem water-methanol extracts from E. cotinifolia and E. tirucalli. The therapeutic indexes of these two plant species were > 7.1; these extracts exhibited no cytotoxicity. Six extracts (13%) representing 4 plant species (40%) showed cytotoxic activity. The highest cytotoxicity was found in the dichloromethane extract obtained from E. cotinifolia leaves and the CC50 values for the most susceptible cell lines, HEp-2 and CHO, were 35.1 and 18.1 microgram/ml, respectively.
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Antineoplásicos Fitogênicos/farmacologia , Antivirais/farmacologia , Euphorbia/química , Herpesvirus Humano 2/efeitos dos fármacos , Animais , Antineoplásicos Fitogênicos/toxicidade , Antivirais/toxicidade , Células CHO/efeitos dos fármacos , Células Cultivadas/efeitos dos fármacos , Colômbia , Colorimetria , Cricetinae , Ensaios de Seleção de Medicamentos Antitumorais , Determinação de Ponto Final , Feminino , Células HeLa/efeitos dos fármacos , Humanos , Extratos Vegetais/farmacologia , Extratos Vegetais/toxicidadeRESUMO
Forty-seven plant extracts of 10 species of the genus Euphorbia (Euphorbiaceae) used by Colombian traditional healers for the treatment of ulcers, cancers, tumors, warts, and other diseases, were tested in vitro for their potential antitumour (antiproliferative and cytotoxic) and antiherpetic activity. To evaluate the capacity of the extracts to inhibit the lytic activity of herpes simplex virus type 2 (HSV-2) and the reduction of viability of infected or uninfected cell cultures, the end-point titration technique (EPTT) and the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] colorimetric assay were used, respectively. The therapeutic index of the positive extracts for the antiviral activity was determined by calculating the ratio CC50 (50 percent cytotoxic concentration) over IC50 (50 percent inhibitory concentration of the viral effect). Five of the 47 extracts (11 percent) representing 3 out of 10 Euphorbia species (30 percent) exhibited antiherpetic action; the highest activity was found in the leaf/stem water-methanol extracts from E. cotinifolia and E. tirucalli. The therapeutic indexes of these two plant species were > 7.1; these extracts exhibited no cytotoxicity. Six extracts (13 percent) representing 4 plant species (40 percent) showed cytotoxic activity. The highest cytotoxicity was found in the dichloromethane extract obtained from E. cotinifolia leaves and the CC50 values for the most susceptible cell lines, HEp-2 and CHO, were 35.1 and 18.1 æg/ml, respectively
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Humanos , Animais , Feminino , Cricetinae , Antivirais , Euphorbia/química , Herpesvirus Humano 2 , Extratos Vegetais , Antivirais , Células Cultivadas , Colômbia , Colorimetria , Determinação de Ponto Final , Extratos VegetaisRESUMO
La interpretacion de la fisiologia ácido-base ha sido revolucionada por la aproximacion cuantitativa de Stewart, a veces llamada "de los iones fuertes". Presentamos el caso clinico de una paciente con acidosis dilucional, entidad con muy pocos informes en la literatura. Tambien discutimos los conceptos más generales de dicha aproximacion.
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AcidoseRESUMO
Se presenta el caso de un recién nacido, con síndrome de Apert acrocefalosindactilia Tipo I, una condición genética caracterizada por malformación craneofacial y sindactilia simétrica de manos y pies. También se asocia a otras alteraciones esqueléticas y anomalías viscerales
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AcrocefalossindactiliaRESUMO
El carcinoma de células renales es una entidad que se presenta en pacientes adultos/ más frecuentemente en la quinta y sexta década de la vida y es rara su presentación en los pacientes pediátricos y más aún la asociación con angiomiolipoma renal. Reportamos un caso de carcinoma renal en un niño de 9 años asociado a angiomiolipoma y se hace una revisión de la literatura. El carcinoma de células renales es un tumor poco común en la infancia, actualmente hay 258 casos reportados en la literatura. El carcinoma de células renales comprende solo el 2.3 al 6.6 por ciento de los tumores renales en niños, mientras que el tumor de Wilms constituye del 85 al 87 por ciento. De manera similar sólo del 0.3 al 1.3 por ciento de todos lo carcinomas de células renales se presentan durante la infancia. De un estimado de 24.000 nuevos casos de carcinoma renal en los Estados Unidos cada año, en niños solo se presentarán entre 70 y 300 casos. De la misma manera, solamente existen reportados en la literatura mundial 28 casos en donde coexista el carcinoma renal y angiomiolipoma en el paciente pediátrico
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Humanos , Masculino , Criança , Neoplasias RenaisRESUMO
La evaluación vesical funcional en los pacientes a los cuales se les va a cerrar la vesicostomía de manera definitiva, siempre ha sido difícil, al no obtenerse un adecuado cierre de la misma. Basados en los reportes de la literatura presentamos la experiencia con el botón de gastrostomía en el Hospital de la Misericordia. La evaluación de la función vesical, la cual es esencial antes de restablecer la continuidad de la vía urinaria, se hace mediante estudios radiográficos y urodinámicos. No obstante esta evaluación es técnicamente difícil de desarrollar en niños con vesicostomía y se presentan fallas para predecir con exactitud antes de su cierre, características como adaptabilidad, vaciamiento y continencia. Ha sido descrita en la literatura una nueva opción de cierrede esta con el botón de gastrostomía de Bard. Con el botón en posición fue posible evaluar con exactitud la función y comportamiento, así mismo las posibles alteraciones del tracto urinario superior
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Humanos , Masculino , Criança , Bexiga Urinária , Urodinâmica/fisiologiaRESUMO
Para valorar la relación entre el crecimiento y los cambios hormonales en los niños con Insuficiencia Renal Crónica (IRC), se realizó un estudio en el cual se incluyeron 13 pacientes. Se realizó valoración clínica trimestral y se cuantificaron los niveles séricos de la hormona de crecimiento (GH) y del factor de crecimiento similar a la insulina tipo I (IGF-I), y su proteína fijadora tipo 3 (BP3). La edad fue de 8.4ñ 4.8 años (Mñ DS) y la talla se encontraba a -2.3ñ 2.67 DS de la media y la velocidad de crecimiento fue de -2.2ñ 1.9 DS. Los niveles de GH fueron de 15.4ñ 2.7 ng/ml. los niveles del IGF-I fueron de 229.3 241ñ 169.2 ng/ml y los niveles del BP 3 fueron de 7.6ñ1.7 ng/ml. Se encontró una correlación positiva entre los niveles del IGF-I y la edad, la velocidad de crecimiento, y los niveles del BP 3 (p=0.004, 0.04, 0.01 respectivamente). En conclusión los pacientes con IRC no presentan alteración hormonales que explican la talla baja y la causa principal se encuentra a nivel periférico en la acción de las hormonas y factores de crecimiento
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Humanos , Criança , Hormônio do Crescimento/administração & dosagem , Hormônio do Crescimento/uso terapêutico , Crescimento/fisiologia , Insuficiência Renal CrônicaRESUMO
Synthetic peptides derived from the amino acid sequence of MTP40, a recently characterized Mycobacterium tuberculosis protein, were tested by two different immunological assays in 91 individuals. For the purposes of this study, the population was distributed in four groups: active tuberculosis (TBC) patients with elevated bacillus loads (BK+), active TBC patients with low bacillus loads (BK-), healthy individuals living in the same household with tuberculous patients (HH), and normal individuals, who had presumably never been in contact with the bacilli (control). We found that T cells of individuals belonging to the HH group showed the highest and most frequent recognition of these peptides in a T-cell proliferation assay, while their antibodies showed the lowest recognition of these peptides when tested by enzyme-linked immunosorbent assay. In contrast, TBC patients revealed an inverse pattern of immune response. Interestingly, one of these peptides (P7) was recognized by T cells of 64% of the HH individuals and by 4.5% of normal donors. Another peptide (P4) was recognized by 55% of sera from BK+ patients and by 5.5% of normal donors. The results presented here indicate the existence of T- and B-cell epitopes within the MTP40 protein. Given the particular recognition pattern of this protein, added to the fact that it appears to be a species-specific antigen of M. tuberculosis, a detailed study of the immune response to it may be useful in the design of more accurate diagnostic tests and an improved vaccine against human TBC.