Mitochondrial and sex steroid hormone crosstalk during aging

Decline in circulating sex steroid hormones accompanies several age-associated pathologies which may influence human healthspan. Mitochondria play important roles in biosynthesis of sex steroid hormones, and these hormones can also regulate mitochondrial function. Understanding the cross talk between mitochondria and sex steroid hormones may provide insights into the pathologies associated with aging. The aim of this review is to summarize the current knowledge regarding the interplay between mitochondria and sex steroid hormones during the aging process. The review describes the effect of mitochondria on sex steroid hormone production in the gonads, and then enumerates the contribution of sex steroid hormones on mitochondrial function in hormone responsive cells. Decline in sex steroid hormones and accumulation of mitochondrial damage may create a positive feedback loop that contributes to the progressive degeneration in tissue function during aging. The review further speculates whether regulation between mitochondrial function and sex steroid hormone action can potentially influence healthspan

Duality Symmetry in Kaluza-Klein n+D+dn+D+d Dimensional Cosmological Model

It is shown that, with the only exception of $n=2$, the Einstein-Hilbert action in $n+D+d$ dimensions, with $n$ times, is invariant under the duality transformation $a\to \frac{1}{a}$ and $b\to \frac{1}{b}$, where $a$ is a Friedmann-Robertson-Walker scale factor in $D$ dimensions and $b$ a Brans-Dicke scalar field in $d$ dimensions respectively. We investigate the $2+D+d$ dimensional cosmological model in some detail.Comment: 23 pages, Late

Stochastic pump of interacting particles

We consider the overdamped motion of Brownian particles, interacting via particle exclusion, in an external potential that varies with time and space. We show that periodic potentials that maintain specific position-dependent phase relations generate time-averaged directed current of particles. We obtain analytic results for a lattice version of the model using a recently developed perturbative approach. Many interesting features like particle-hole symmetry, current reversal with changing density, and system-size dependence of current are obtained. We propose possible experiments to test our predictions.Comment: 4 pages, 2 figure

The deep-pocket effect of internal capital markets

We provide evidence that incumbent and entrant firms' access to business group deep pockets affects entry patterns in product markets. Relying on a unique French data set on business groups, our paper shows that entry in manufacturing industries is negatively related to the cash hoarded by incumbent-affiliated groups, and positively related to entrant groups' cash. In line with theoretical predictions, we find that the impact on entry of group cash holdings is more important in environments where financial constraints are pronounced and in more financially dependent sectors. The cash holdings of incumbent and entrant groups also affect the survival rate of entrants in the 3 to 5 year post-entry window. Overall, our findings suggest that internal capital markets operate within corporate groups and affect the product market behavior of affiliated firms by mitigating financial constraints

Sustitución ureteral bilateral con asa ileal

Indexación: Web of Science; ScieloUreteral replacement by a loop of defunctionalized ileum was described more than 2 centuries ago and continues to be a therapeutic option at present. This series describes the technique of bilateral ureteral replacement with ileum. Aim: To report 4 cases of bilateral ileal ureteral replacement performed at our institution, its indications, the surgical technique, complications, and a review of the literature. Material and Method: We report 4 cases of extensive bilateral ureteral injury of different etiologies, whose treatment with curative intent was to replace the damaged ureter with a isoperistaltic small bowel segment. Results: The surgical technique used was standard in all cases. There were no intraoperative complications and only one patient had hyperchloremic acidosis. No patient has shown loss of renal function in the long-term follow up. Conclusion: Is an effective therapeutic, safe and reproducible technique to replacement of major bilateral ureteral injuries, independent of the original cause.La sustitución ureteral por un asa de íleon desfuncionalizada fue descrita hace más de 2 siglos y continúa siendo una alternativa terapéutica en la actualidad. Esta serie describe la técnica de sustitución ureteral bilateral con íleon. Objetivo: Presentar 4 casos de sustitución ureteral ileal bilateral realizados en nuestro centro, indicaciones de la técnica quirúrgica, complicaciones y revisión de la literatura. Material y Método: Presentamos 4 casos de lesión ureteral bilateral extensa, de etiologías diferentes, cuyo tratamiento con intención curativa fue la sustitución de la lesión ureteral por un segmento intestinal isoperis-táltico. Resultados: La técnica quirúrgica empleada fue estándar en todos los casos. No hubo complicaciones intraoperatorias, y sólo una paciente presentó descompensación metabólica por acidosis hiperclorémica. En ningún paciente se ha demostrado pérdida en la función renal. Conclusión: El segmento intestinal de íleon desfuncionalizado es una alternativa terapéutica eficaz, segura y reproducible, para el reemplazo de importantes lesiones ureterales bilaterales, independiente de la causa original.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-40262012000500012&nrm=is