Chaotic vortex-induced rotation of an elliptical cylinder.

Non-linear oscillations of an elliptical cylinder, which can rotate about an axis that passes through its symmetry axle due to a torsional spring and hydrodynamic torque produced by the flow of a Newtonian fluid, were analyzed in terms of a single parameter that compares vortex shedding frequency with the torsional spring's natural frequency. The governing equations for the flow coupled with a rigid body with one degree of freedom were solved numerically using the lattice-Boltzmann method. The Reynolds number used was Re=200, which, in the absence of torsional spring, produces chaotic oscillations of the elliptical cylinder. When the torsional spring is included, we identified three branches separated by transition regions when stiffness of the restorative torque changes, as in the case of vortex-induced vibrations. However, in this case, several regions presenting chaotic dynamics were identified. Two regions with stable limit cycles were found when both torques synchronized and when stiffness of the torsional spring is big enough so that the ellipse's oscillation is small.

Nefrectomía parcial en tumores sobre 4 Cms: evolución posperatorio resultados oncológicos y complicaciones / Partial nephrectomy for tumors over 4 cms: postoperatory evolution oncological results and complications

La nefrectomía parcial (NP) es el tratamiento de elección para tumores renales malignos menores de 4 cm, ya que ha demostrado resultados oncológicos equivalentes y una sobrevida global superior a la nefrectomía radical. Esto se explica debido a la capacidad de la NP de preservar la función renal y prevenir los efectos deletéreos asociados a la disfunción renal. Existe una cantidad creciente de estudios que indican que esta ventaja seria también extensible a tumores estadio T1b (4-7 cm). Este trabajo, evalúa los resultados oncológicos de la NP en tumores mayores de 4 cms y las complicaciones con un score validado y reproducible. Material y métodos: Se identificó, de manera retrospectiva, a un total de 214 pacientes sometidos a nefrectomía parcial entre los años 2002 al 2009. De éstos, 39 presentaban tumor mayor de 4 cms. Se excluyeron aquellos pacientes que presentaban metástasis al momento del diagnóstico, los con seguimiento menor a 6 meses y/o, tumores no esporádicos. Se analizaron las variables categóricas y continuas con los test Chi cuadrado y Mann-Whitney, respectivamente. Se utilizó el análisis de Kaplan-Meier para calcular la sobrevida global y cáncer especifica. Se clasificaron las complicaciones según score de Clavien. Resultados: Se identificaron 45 tumores en 39 pacientes. La edad media fue de 61 años (110, 7). El tamaño promedio tumoral fue de 5, 7cms. En 7 pacientes la indicación de nefrectomía fue absoluta (riñón solitario o contralateral atrófico), mientras que fue electiva en 32 (82 por ciento). El estudio anátomo-patológico demostró 87,1 por ciento (34) de tumores malignos y 12, 9 por ciento (5), benignos. Luego de un seguimiento promedio de 35, 9 meses (media de 34 meses), la sobrevida fue de 92,3 por ciento, sin detectarse muertes a causa del tumor renal...

The role of nephron-sparing surgery (NSS) is well established for T1 a renal lesions (<4 cm). Renal tumor control achieved by NSS is equivalent to one achieved by Radical Nephrectomy (RN) in appropriate/y selected patients, offering the benefits of decreased renal insufficiency rate when compared to RN. Recent data for renal tumors > 4 cms have suggested that it might be possible to expand the indication of NSS, with comparable oncological and clinical outcomes. However, NSS for tumors > 4 cms has been associated with a slight/y higher rate of complications. Objectives: To evaluate the oncological and clinical outcomes of NSS for renal tumor > 4 cms and to assess the complications based in a graded, va/idated and reproducible score (Clavien grade ). Material and methods: After the approval of the institutional ethic board, we retrospectively identified 214 patients who underrnt NSS for renal tumors. Thirty nine patients had tumors over 4 cms. The study period was from 2002 to 2009. Patients with metastasis at the time of diagnosis, follow-up less than 6 months or with non-sporadic tumors were excluded from the study Continues and categorical variable were assessed with Mann- Whitney U test and chis-quare test, respectively. Kaplan-Meier analysis was used to calculate the overall survival and cancer specific survival rate. The assessment of the complication was done using the Clavien score. RESULTS Forty five tumors were identified ¡n 39 patients. The median age was 61 year r 10. 7. Median tumor size was 5. 7cms. The surgical indication was imperative in 7 patients (solitary kidney or contralateral atrophic kidney) and elective in 32 (82 percent). The final pathology report showed that 32 (87,1 percent) and 5 (12,9 percent) tumors were malignant and benign, respectively After a mean folIow- up of 35.9 months (median 34 months), the over all survival rate was 92,3 percent while none had died from renal tumors...

CD4+ T lymphocyte depletion attenuates lipopolysaccharide-induced tumor necrosis factor secretion by alveolar macrophages in the mouse.

Mechanisms underlying the control of cytokine secretion by alveolar macrophages are not fully understood. We hypothesized that T lymphocytes or their products modulate the capacity of alveolar macrophages to release cytokines in response to an exogenous stimulus. In this study, we investigated the role of lymphocytes expressing surface CD4 (CD4+) antigen in the regulation of tumor necrosis factor alpha (TNF-alpha) secretion by alveolar macrophages. Specific pathogen-free male BALB/c mice were injected intraperitoneally with 0.3 mg monoclonal anti-CD4 antibody or phosphate-buffered saline. Depletion of CD4+ splenic lymphocytes was confirmed 6 days later by flow cytometry. On day 6, mice were challenged intratracheally with E. coli lipopolysaccharide (LPS, 1-100 micrograms/100 g BW) or phosphate-buffered saline. The lungs were lavaged 3 h later and the bronchoalveolar lavage fluid assessed for TNF activity and cell recovery (total and differential). No TNF was detected in the lavage fluid of animals pretreated with antibody or phosphate-buffered saline and given phosphate-buffered saline intratracheally. However, the saline-treated mice challenged with LPS (100 micrograms/100 g BW) released 3.76 +/- 0.18 ng TNF/ml bronchoalveolar lavage fluid. In contrast, mice depleted of CD4+ T lymphocytes released almost 50% less TNF (1.94 +/- 0.23 ng TNF/ml lavage fluid, p < 0.001) in response to the same dose of LPS.(ABSTRACT TRUNCATED AT 250 WORDS)