Biomass and lipid production by the native green microalgae Chlorella sorokiniana in response to nutrients, light intensity, and carbon dioxide: experimental and modeling approach.

Introduction: Microalgae are photosynthetic cells that can produce third-generation biofuels and other commercial compounds. Microalgal growth is influenced by two main parameters: light intensity and carbon dioxide concentration, which represent the energy and carbon source, respectively. For photosynthesis, the optimum values of abiotic factors vary among species. Methods: In this study, the microalga Chlorella sorokiniana was isolated from a freshwater lake. It was identified using molecular analysis of the ribosomal internal transcribed spacer. A single-factor design of experiments in 250-mL Erlenmeyer flasks was used to evaluate which concentrations of nitrogen and phosphorus increase the production of biomass and lipids. The response surface methodology was used with a 32-factorial design (light intensity and CO2 were used to evaluate its effect on biomass, lipid production, and specific growth rates, in 200-mL tubular photobioreactors (PBRs)). Results and Discussion: Low levels of light lead to lipid accumulation, while higher levels of light lead to the synthesis of cell biomass. The highest biomass and lipid production were 0.705 ± 0.04 g/L and 55.1% ± 4.1%, respectively. A mathematical model was proposed in order to describe the main phenomena occurring in the culture, such as oxygen and CO2 mass transfer and the effect of light and nutrients on the growth of microalgae. The main novelties of this work were molecular identification of the strain, optimization of culture conditions for the indigenous microalgae species that were isolated, and formulation of a model that describes the behavior of the culture.

Production, characterization and kinetic model of biosurfactant produced by lactic acid bacteria

BACKGROUND Biosurfactants are surface active molecules produced by microorganisms which have the ability to disrupt the plasma membrane. Biosurfactant properties are important in the food, pharmaceu tical and oil industries. Lactic acid bacteria can produce cell-bound and excreted biosurfactants. RESULTS The biosurfactant-producing ability of three Lactobacillus strains was analyzed, and the effects of carbon and nitrogen sources and aeration conditions were studied. The three species of lactobacillus eval uated were able to produce biosurfactants in anaerobic conditions, which was measured as the capacity of one extract to reduce the surface tension compared to a control. The decreasing order of biosurfactant production was L. plantarum>Lactobacillus sp.>L. acidophilus. Lactose was a better carbon source than glu cose, achieving a 23.8% reduction in surface tension versus 12.9% for glucose. Two complex nitrogen sources are required for growth and biosurfactant production. The maximum production was reached at 48 h under stationary conditions. However, the highest level of production occurred in the exponential phase. Biosurfactant exhibits a critical micelle concentration of 0.359 ± 0.001 g/L and a low toxicity against E. coli. Fourier transform infrared spectroscopy indicated a glycoprotein structure. Additionally, the kinetics of fermentation were modeled using a logistic model for the biomass and the product, achieving a good fit (R2 > 0.9). CONCLUSIONS L. plantarum derived biosurfactant production was enhanced using adequate carbon and nitrogen sources, the biosurfactant is complex in structure and because of its low toxicity could be applied to enhance cell permeability in E. coli

Relationship between anode material, supporting electrolyte and current density during electrochemical degradation of organic compounds in water.

Taking crystal violet (CV) dye as pollutant model, the electrode, electrolyte and current density (i) relationship for electro-degrading organic molecules is discussed. Boron-doped diamond (BDD) or Iridium dioxide (IrO2) used as anode materials were tested with Na2SO4 or NaCl as electrolytes. CV degradation and generated oxidants showed that degradation pathways and efficiency are strongly linked to the current density-electrode-electrolyte interaction. With BDD, the degradation pathway depends on i: If ii(lim), generated oxidants play a major role in the CV elimination. When IrO2 was used, CV removal was not dependent on i, but on the electrolyte. Pollutant degradation in Na2SO4 on IrO2 seems to occur via IrO3; however, in the presence of NaCl, degradation was dependent on the chlorinated oxidative species generated. In terms of efficiency, the Na2SO4 electrolyte showed better results than NaCl when BDD anodes were employed. On the contrary, NaCl was superior when combined with IrO2. Thus, the IrO2/Cl(-) and BDD/SO4(2-) systems were better at removing the pollutant, being the former the most effective. On the other hand, pollutant degradation with the BDD/SO4(2-) and IrO2/Cl(-) systems is favored at low and high current densities, respectively.

Effects of sonochemical parameters and inorganic ions during the sonochemical degradation of crystal violet in water.

This work deals with the ultrasonic degradation (800 kHz) of crystal violet (CV) under different experimental conditions. The effects of saturating gas (argon, carbon dioxide and air), CV concentration (2.45-1225 µmol L(-1)), pH (3-9) and power (20-80 W) were evaluated. The best performances were obtained at 80 W with argon as a saturating gas. The pH had no significant effect. The influence of several water matrices containing anions (chloride, sulphate and bicarbonate) and cations (Fe(2+)) on the sonolytic degradation of CV was also investigated. Significant differences were not observed with the presence of chloride and sulphate. However, at relatively low pollutant concentration (2.45 µmol L(-1)) bicarbonate showed a particular effect: a high bicarbonate concentration (350 mmol L(-1)) produced a detrimental effect, while a low bicarbonate concentration (3 mmol L(-1)) increased the efficiency of the process. The presence of Fe(2+) (1 mmol L(-1)) also increased the CV (49 µmol L(-1)) degradation by 32% after 180 min. Analyses of intermediates by GC-MS led to the identification of several sonochemical by-products: N,N-dimethylaminobenzene, 4-(N,N-dimethylamino)-4'-(N',N'-dimethylamino)benzophenone, and N,N,N',N'-tetramethyl-4,4'-diaminodiphenylmethane. The presence of these aromatic structures showed that the main ultrasonic CV degradation pathway is linked to the reaction with *OH radicals. At the end of the treatment, these early products were converted into biodegradable organic by-products which could be easily treated in a subsequent biological treatment.

Electrochemical degradation of crystal violet with BDD electrodes: effect of electrochemical parameters and identification of organic by-products.

This paper explores the applicability of electrochemical oxidation on a triphenylmethane dye compound model, hexamethylpararosaniline chloride (or crystal violet, CV), using BDD anodes. The effect of the important electrochemical parameters: current density (2.5-15 m A cm(-2)), dye concentration (33-600 mg L(-1)), sodium sulphate concentration (7.1-50.0 g L(-1)) and initial pH (3-11) on the efficiency of the electrochemical process was evaluated. The results indicated that while the current density was lower than the limiting current density, no side products (hydrogen peroxide, peroxodisulphate, ozone and chlorinated oxidizing compounds) were generated and the degradation, through OH radical attack, occurred with high efficiency. Analysis of intermediates using GC-MS investigation identified several products: N-methylaniline, N,N-dimethylaniline, 4-methyl-N,N-dimethylaniline, 4-methyl-N-methylaniline, 4-dimethylaminophenol, 4-dimethylaminobenzoic acid, 4-(N,N-dimethylamino)-4'-(N',N'-dimethylamino) diphenylmethane, 4-(4-dimethylaminophenyl)-N,N-dimethylaniline, 4-(N,N-dimethylamino)-4'-(N',N'-dimethylamino) benzophenone. The presence of these aromatic structures showed that the main CV degradation pathway is related to the reaction of CV with the OH radical. Under optimal conditions, practically 100% of the initial substrate and COD were eliminated in approximately 35 min of electrolysis; indicating that the early CV by-products were completely degraded by the electrochemical system.

Experimental design approach applied to the elimination of crystal violet in water by electrocoagulation with Fe or Al electrodes.

An experimental design methodology was applied to evaluate the decolourization of crystal violet (CV) dye by electrocoagulation using iron or aluminium electrodes. The effects and interactions of four parameters, initial pH (3-9), current density (6-28 A m(-2)), substrate concentration (50-200 mg L(-1)) and supporting electrolyte concentration (284-1420 mg L(-1) of Na(2)SO(4)), were optimized and evaluated. Although the results using iron anodes were better than for aluminium, the effects and interactions of the studied parameters were quite similar. With a confidence level of 95%, initial pH and supporting electrolyte concentration showed limited effects on the removal rate of CV, whereas current density, pollutant concentration and the interaction of both were significant. Reduced models taking into account significant variables and interactions between variables have shown good correlations with the experimental results. Under optimal conditions, almost complete removal of CV and chemical oxygen demand were obtained after electrocoagulation for 5 and 30 min, using iron and aluminium electrodes, respectively. These results indicate that electrocoagulation with iron anodes is a rapid, economical and effective alternative to the complete removal of CV in waters. Evolutions of pH and residual iron or aluminium concentrations in solution are also discussed.

Acidente por injeção medicamentosa no músculo deltoide: lesões locais e à distância, revisão de 32 casos / Intramuscular accident with drug injection in the deltoid muscle: local and distant lesions, review of 32 cases

Análise de 32 casos de acidentes por injeção, na maioria das vezes, de substâncias oleosas no músculo deltoide. Os acidentes caracterizaram-se por dor e reações tróficas locais. Em muitos casos, simultaneamente, ocorreram distúrbios isquêmicos nas regiões escapular, peitoral e, especialmente, na extremidade do membro. Presume-se que esse complexo lesional é gerado: 1) pela ação lesiva do medicamento nas terminações nervosas, nos tecidos moles e perivasais; e/ou 2) pela entrada fortuita da substância no interior dos vasos, produzindo embolia e/ou endotelite trombosante; e/ou 3) pelo despertar de fenômenos vasomotores. As lesões da mão, geralmente, foram mais graves que as lesões deltoidianas, com a eventual perda de dedos, espontânea ou cirúrgica. Os diversos quadros clínicos do acidente foram semelhantes, mas algumas características lesionais permitiram identificar mecanismos fisiopatogênicos peculiares, o que tem significado conceitual e terapêutico.

Analysis of 32 cases of accidental injection of oily suspension (in most cases) into the deltoid muscle is reported. Pain and local ulcers characterized the accidents. In many cases, simultaneous ischemic disorders were observed in the scapular and pectoral regions and especially in the end of the upper limb. It is presumed that this complex lesion was caused by 1) the harmful action of the medication on nervous terminations, soft and perivascular tissues; and/or 2) occasional entrance of the substance into blood vessels, causing embolism and/or thrombotic endothelitis; and/or 3) vasomotor phenomena. Hand injuries were generally more severe than injuries in the deltoid region, with occasional spontaneous or surgical loss of fingers. Clinical statuses were similar, though some lesions had features, which allowed identification of peculiar physiopathogenic mechanisms, with conceptual and therapeutic significance.

Disruption of Tsc2 in pancreatic beta cells induces beta cell mass expansion and improved glucose tolerance in a TORC1-dependent manner.

Regulation of pancreatic beta cell mass and function is a major determinant for the development of diabetes. Growth factors and nutrients are important regulators of beta cell mass and function. The signaling pathways by which these growth signals modulate these processes have not been completely elucidated. Tsc2 is an attractive candidate to modulate these processes, because it is a converging point for growth factor and nutrient signals. In these experiments, we generated mice with conditional deletion of Tsc2 in beta cells (betaTsc2(-/-)). These mice exhibited decreased glucose levels and hyperinsulinemia in the fasting and fed state. Improved glucose tolerance in these mice was observed as early as 4 weeks of age and was still present in 52-week-old mice. Deletion of Tsc2 in beta cells induced expansion of beta cell mass by increased proliferation and cell size. Rapamycin treatment reversed the metabolic changes in betaTsc2(-/-) mice by induction of insulin resistance and reduction of beta cell mass. The reduction of beta cell mass in betaTsc2(-/-) mice by inhibition of the mTOR/Raptor (TORC1) complex with rapamycin treatment suggests that TORC1 mediates proliferative and growth signals induced by deletion of Tsc2 in beta cells. These studies uncover a critical role for the Tsc2/mTOR pathway in regulation of beta cell mass and carbohydrate metabolism in vivo.

Chile y la globalización: una dependencia potencialmente peligrosa / Chile and globalization: a potentially dangerous dependence

Este ensayo tiene varios propósitos. Primero, discutir el concepto de globalización en sus diferentes acepciones, particularmente, la económica, la política y la cultural. En segundo lugar, intenta tratar de describir y demostrar el enorme grado de dependencia que Chile tiene del actual proceso globalizador. En tercer término, se trata de señalar que la actual globalización, es un proceso similar al que ha ocurrido en otras épocas de la historia. Especialmente se comenta en detalle el análisis del profesor Ferguson quien compara la actual globalización con la que ocurrió a fines del siglo XIX y comienzos del XX. Se concluye que el actual proceso de globalización es tan volátil, inestable y peligroso como fue la globalización decimonónica. Se concluye también indicando que es altamente probable que el actual proceso globalizador, termine en forma similar a como terminó la globalización 1870-1914. Finalmente se argumenta que debido a que Chile está geográficamente ubicado en la parte más austral del hemisferio sur, es probable que el país salga relativamente intacto de la conflagración que se avecina.

This article begins by discussing the different meanings of globalization, especially the economic, political and social ones. It then describes how Chile is greatly dependent on the current globalization process, as well as points out that this process is similar to others that have taken place in other times in history. It discusses in detail professor Ferguson's analysis comparing the current globalization with the one that occurred at the end of the 19th century and the beginning of the 20th. The article concludes that the current process is as volatile, unstable and dangerous as that of the 19th century, and that it is highly probable that it will end as that of 1870-1914. It also argues that since Chile is on the southernmost part of the southern hemisphere, it will be relatively preserved from the oncoming conflagration.

Trombogênese - trombofilia / Thrombogenesis - thrombophilia

A doença tromboembólica vem sendo alvo de intensas pesquisas desde o fim do século XVIII na tentativa de se determinar uma explicação para sua incidência e seu desenvolvimento. Entretanto, ainda não se tem um estudo detalhado de todos os fatores intrínsecos e extrínsecos que podem levar ao quadro clínico de trombose. Assim, após uma breve revisão histórica das descobertas e das hipóteses levantadas sobre a trombofilia, o artigo prosegue com a descrição de fatores de risco que têm sido alvo de pesquisas detalhadas no intuito de proporcionar tratamentos profiláticos eficazes...

Perfil hemodinámico en comparación con perfil biofísico como prueba de bienestar fetal / Hemodynamic profile in comparison to biophysical profile for assessment of fetal well-being

Establecer un perfil hemodinámico doppler como una prueba de bienestar fetal antenatal y compararlo con el perfil biofísico fetal en cuanto a su eficacia diagnóstica de acidosis y morbilidad fetal. Estudio prospectivo de 41 gestantes de alto riesgo sometidas a cesárea segmentaria, entre abril de 1999 a marzo de 2000. Unidad de Perinatología "Dr. Freddy Guevara" del Hospital Universitario de Caracas. La edad de gestación media fue de 37,2 semanas. El perfil biofísico fetal fue anormal en el 56,1 por ciento casos (n = 23), mientras que el perfil hemodinámico doppler lo fue en el 61,0 por ciento (n = 25). De los recién nacidos, 13 (31,7 por ciento) presentaron acidosis, y 15 (36,6 por ciento) crecimiento fetal restringido. El perfil hemodinámico doppler superó en forma significativa al perfil biofísico fetal para predecir acidemia y morbilidad perinatal. El análisis de regresión logística de la escala de puntuación hemodinámica demostró que en menor puntuación mayor es la severidad de la acidemia. El perfil hemodinámico doppler demostró ser un método antenatal eficaz para predecir acidemia y morbilidad fetal, sin embargo, sugerimos complementarlo con otras pruebas com el perfil biofísico fetal

Hallazgos anatomopatológicos en la hipertensión inducida por el embarazo, 1981-1994 / Anatomopathological in the pregnancy induced hypertension, 1981-1994

Conocer los hallazgos anatomopatológicos en los diferentes órganos de pacientes con hipertensión inducida por el embarazo. Se revisaron 358 protocolos de autopsia de pacientes entre 1981-1994 y se encontraron 50 casos con diagnóstico de hipertensión inducida por el embarazo. Fueron analizados: edad, tiempo de gestación, tipo clínico de hipertensión y las alteraciones encontradas en diferentes órganos. Maternidad Concepción Palacios. Caracas. Los principales órganos afectados por la hipertensión inducida por el embarazo por orden de frecuencia fueron: encéfalo en 42 autopsias (84 por ciento), pulmones en 39 casos (78 por ciento), riñón e higado con 35 casos cada uno (70 por ciento) y corazón con 20 (40 por ciento). Se encontraron 18 hematomas subcapsulares hepáticos (36 por ciento) de los cuales 7 (14 por ciento) estaban rotos. Las alteraciones anatomopatológicas más relevantes se observaron en : encéfalo, higado y riñón. La hipertensión inducida por el embarazo continúa siendo causa de mortalidad importante en nuestro medio, por lo que amerita estudio y actualizaciones constante para su control adecuado

Dos casos de corioangioma en el Hospital Universitario de Caracas / Two cases of chorioangioma Universitary Hospital of Caracas

Se presentan las historias clínicas de dos pacientes con diagnóstico anatomopatológico de corioangioma en el Hospital Universitario de Caracas en 1985 y 1991 y se revisa la literatura existente

Hidropesía fetal infecciosa: tratamiento en útero: caso clínico / Infectious hidrops fetalis: treatment in uterus: case clinic

Comunicamos el caso de una paciente de 22 años de edad, referida a la Unidad de Perinatología del Hospital Universitario de Caracas con diagnóstico de embarazo simple de 29 semanas e hidropesia fetal. Se realizaron las pruebas serológicas para determinar su causa e instalar el tratamiento adecuado. El diagnóstico final fue hidrops fetal no inmunológico. La embarazada tuvo parto normal a término con recién nacida que pesó 2 780 g y midio 48 cm. Presentó VDRL positivo; recibio tratamiento con penicilina y fue referida a la consulta de enfermedades de transmisión sexual del Servicio de Dermatología para su control y seguimiento

Holoprosencefalia: cebocefalia y ciclopadia: aspectos clínicos / Holoprosencephaly: cebocephaly and cyclopia: clinical aspect

Se presenta un estudio retrospectivo sobre la incidencia de las holoprosencefalias más frecuentes: cíclopes y cebocéfalos en la Maternidad "Concepción Palacios" desde 1949 a 1996. Se encontró que la incidencia global de holoprosencefalia es de 1 x 40 691 partos. La incidencia de cíclopes es de 1 x 51 115 partos y las de los cebocéfalos es de 1 x 31 712 partos. Se describen las malformaciones externas e internas asociadas y el diagnóstico pre y posnatal

Estreptococo beta hemolítico del grupo B en pacientes en trabajo de parto y sus neonatos / Beta hemolytic group B Streptococcus in patients in labor and their neonates

Determinar la incidencia de colonización vaginal por estreptococo beta hemolítico del grupo B de pacientes en trabajo de parto y la contaminación de sus recién nacidos. Admisión y Sala de Partos de la Maternidad "Concepción Palacios". Estudio prospectivo al azar entre noviembre 1995 a enero 1996. Se cultivaron muestras vaginales de 70 pacientes en trabajo de parto y muestras de mucosa nasal de sus recién nacidos. Las colonias sugestivas de estreptococo del grupo B se tipificaron serológicamente, mediante el test de Phadebact Streptococo. Nueve de las madres (12,86 por ciento) resultaron portadoras del germen. No se encontró relación estadísticamente significativa entre el ser portador de estreptococo ß hemolitico con la integridad de las membranas, paridad y número de compañeros sexuales. Cinco de los recién nacidos (7,14 por ciento) tuvieron el germen en un porcentaje de contaminación de 55,56 por ciento; de estos ninguno desarrolló enfermedad durante su hospitalización. Consideramos que, debido a la alta mortalidad neonatal relacionada con el estreptococo del grupo B, es necesario realizar mayores estudios de nuestras tanto intra como anteparto

Dehiscencia del segmento uterino: tratamiento quirúrgico conservador / Uterine segment deshiscence: conservative surgical treatment

Evaluar el tratamiento quirúrgico conservador en las pacientes complicadas con dehiscencia del segmento uterino en el puerperio poscesárea. Maternidad "Concepción Palacios", Caracas. Se realizó resección de los bordes necróticos de la histerorrafia, resutura y colocación de drenajes activos en 26 pacientes que presentaron dehiscencia del segmento uterino en el puerperio de cesárea, de las cuales 22 se realizaron en el hospital y 4 fueron referidas de otras instituciones. El 96,15 por ciento (25 casos) evolucionó satisfactoriamente, sólo una (3,85 por ciento) ameritó histerectomía abdominal subtotal por sepsis. Recomendamos el tratamiento como alternativa terapéutica en pacientes que desean conservar su fertilidad

Cáncer de mama en la Maternidad "Concepción Palacios" 1984-1996 / Breast cancer at the Maternidad \"Concepción Palacios\" 1984-1996

Conocer la experiencia de 13 años con el cáncer de mama, en la Maternidad "Concepción Palacios". Estudio retrospectivo desde enero de 1984 hasta diciembre de 1996. Los datos obtenidos fueron tabulados y sometidos a análisis estadísticos mediante la determinación de frecuencias absolutas y relativas. Se encontró que la incidencia global de cáncer de mama es de 1 por 279 pacientes ginecológicas, Entre los factores de riesgo observamos historia familiar, menarquía temprana, edad del primer embarazo después de los 30 años, ingesta de anticonceptivos orales por más de 5 años en 6,45 por ciento de las pacientes. Los métodos diagnósticos fueron la mamografía en 58,62 por ciento y la biopsia por aspiración con aguja fina en 62,5 por ciento de los casos. El 93,55 por ciento de los cánceres eran epiteliales. El tratamiento quirúrgico se realizó en el 93,5 por ciento de las pacientes y como coadyuvante se utilizó radioterapia (54,83 por ciento), quimioterapia (48,38 por ciento) y hormonoterapia (12 por ciento). Cinco pacientes cursaban con embarazo (16,12 por ciento), tres de las cuales tuvieron resolución obstétrica satisfactoria. El diagnóstico de cáncer de mama debe realizarse en forma precoz, su búsqueda sistemática con programas de detección y métodos complementarios como el autoexamen, la exploración física y la mamografía tienen como meta identificar la neoplasia en etapa más temprana y disminuir la mortalidad

Cebocefalia: comunicación de un caso / Cebocephaly: of a case comunication

Presentamos una paciente de 15 años de edad, primigesta, con diagnóstico de embarazo de 19 semanas, microcefalia y tumor de ovario fetal. Presentó disminución de movimientos fetales a las 28 semanas, y el ecosonograma reportó óbito fetal. Se interrumpe el embarazo por vía vaginal obteniendo feto muerto femenino de 1.100 g de peso y 33 cm de talla. El estudio anatomopatológico reportó cebocefalia y quiste simple gigante de ovario izquierdo (13 cm) más superposición de dedos del pie derecho. La incidencia reportada de cebocefalia es de 1 x 27.480 partos. Este es el primer caso reportado en nuestra institución con quiste funcional de ovario