Nitric oxide negatively regulates mammalian adult neurogenesis

Neural progenitor cells are widespread throughout the adult central nervous system but only give rise to neurons in specific loci. Negative regulators of neurogenesis have therefore been postulated, but none have yet been identified as subserving a significant role in the adult brain. Here we report that nitric oxide (NO) acts as an important negative regulator of cell proliferation in the adult mammalian brain. We used two independent approaches to examine the function of NO in adult neurogenesis. In a pharmacological approach, we suppressed NO production in the rat brain by intraventricular infusion of an NO synthase inhibitor. In a genetic approach, we generated a null mutant neuronal NO synthase knockout mouse line by targeting the exon encoding active center of the enzyme. In both models, the number of new cells generated in neurogenic areas of the adult brain, the olfactory subependyma and the dentate gyrus, was strongly augmented, which indicates that division of neural stem cells in the adult brain is controlled by NO and suggests a strategy for enhancing neurogenesis in the adult central nervous system

Determination of the vertical and horizontal coefficient of consolidation in soft organic soils

Wyznaczanie współczynnika konsolidacji pionowej i poziomej w słabonośnych gruntach organicznych jest istotnym uzupełnieniem opisu charakterystyki naprężenie – odkształcenie w gruntach, które charakteryzuje duża anizotropia. Poczżtkowa duża przepuszczalność znacząco malejąca w procesie odkształcenia, duża ściśliwość i nieliniowość parametrów zarówno odkształceniowych, jak i przepływu stanowi wyzwanie dla inżynierów, niejednokrotnie szukających możliwości posadowienia obiektów na słabonośnym podłożu budowlanym. W pracy scharakteryzowano metodę wyznaczania współczynnika konsolidacji, zarówno w kierunku pionowym, jak i poziomym, oraz podano podstawowe zasady laboratoryjnego badania gruntów z wykorzystaniem komory Rowe’a.Determination of the vertical and horizontal coefficient of consolidation in soft organic soils is a significant completion of stress-strain characteristics. The organic soils are characterized by anisotropic structure. Large initial permeability, decreasing during the consolidation process, large compressibility and nonlinear strain and permeability characteristics can be a challenge for engineers building on soft subsoil. In the paper the method and methodology of determination coefficient of consolidation in Rowe cell is presented. Also, the mean rules of testing in Rowe cell are described