Cellular Imaging and Emerging Technologies for Adult Neurogenesis Research

The first report on the generation of new neurons in the adult mammalian brain occurred in the early 1960s, however, nearly 40 years passed before the scientific community generally recognized the existence of adult mammalian neurogenesis. Development of new technologies that facilitate the identification of newborn neurons in the early 1990s has been central to expanding our understanding of adult neurogenesis as a process influencing mammalian brain plasticity. Subsequently, the field of adult neurogenesis progressed tremendously thanks to continuous technical advances allowing in vivo and in vitro manipulations of adult neural progenitors. Today, a core understanding of various aspects of adult neurogenesis has emerged, including neural progenitor proliferation and fate-specification, and the migration, maturation, and synaptic integration of newborn neurons into functional circuits. However, numerous questions remain open. This research topic issue gather

Control mechanisms of circadian rhythms in body composition: Implications for manned spaceflight

The mechanisms underlying the internal synchronization of the circadian variations in electrolyte content in body compartments were investigated, and the significance of these oscillations for manned spaceflight were examined. The experiments were performed with a chair-acclimatized squirrel monkey system, in which the animal sits in a chair, restrained only around the waist. The following information was given: (1) experimental methodology description, (2) summary of results obtained during the first contract year, and (3) discussion of the research performed during the second contract year. This included the following topics: physiological mechanisms promoting normal circadian internal synchronization, factors precipitating internal desynchronization, pathophysiological consequences of internal desynchronization of particular relevance to spaceflight, and validation of a chair-acclimatized system

Free Vibration Analysis of Elastic Orthotropic Rectangular Inclined Damped Highway Supported by Pasternak Foundation under Moving Aerodynamic Automobile

Various plates and plate like structures are often subjected to moving loads, such as aerodynamic automobiles. In this paper automobile highway was modelled as an elastic orthotropic rectangular plate. The effects of damping and drag force were put into consideration. The fourth order differential equation governing such plates resting on Pasternak foundation was expressed as first order differential equation. The equation was changed to its algebraic form using finite difference algorithm, then solved with the aid of MATLAB in conjunction with a computer program. Simple supported conditions were used. The effects of damping drag force, foundation and other physical phenomena were investigated and the results obtained are consistent with the ones existing in literature

Application of Differential Transform Method to Vibration Analysis of Damped Railway Bridge on Pasternak Foundation under Moving Train

In this paper, we used differential transform method (DTM) to analyse free vibration of a railway bridge, modelled as an orthotropic rectangular plate, supported by Pasternak foundation. The effect of damping was considered. The present method transformed the governing equation to its algebraic form. Solution form to similar equation was adopted. The results obtained are in agreement with the ones in literature, and it shows that the technique introduced is easy to apply to such differential equation governing the vibration of such plates

Control mechanisms of circadian rhythms in body composition: Implications for manned spaceflight

The mechanisms that underlie the circadian variations in electrolyte content in body fluid compartments were investigated, and the mechanisms that control the oscillations were studied in order to investigate what effects internal desynchronization in such a system would have during manned space flight. The studies were performed using volunteer human subjects and squirrel monkeys. The intercompartmental distribution of potassium was examined when dietary intake, activity, and posture are held constant throughout each 24-hour day. A net flux of potassium was observed out of the body cell mass during the day and a reverse flux from the extracellular fluid into the body cell mass during the night, counterbalanced by changes in urinary potassium excretion. Experiments with monkeys provided evidence for the synchronization of renal potassium excretion by the rhythm of cortisol secretion with the light-dark cycle. Three models of the circadian timing system were formalized

Renal response to seven days of lower body positive pressure in the squirrel monkey

As a ground-based model for weightlessness, the response of the chair-trained squirrel monkey to lower body positive pressure (LBPP) was evaluated in a length of study similar to a typical Space Shuttle mission (7 days). Results were compared to time control experiments that included chair-sitting without exposure to LBPP. Chronic exposure to LBPP results in an acute diuretic and natriuretic response independent of changes in plasma aldosterone concentrations and produces a chronic reduction in fluid volume lasting the duration in the stimulus

Energy Conservation Analysis of Human Body Locomotion Modelled as an Inverted Quadruple Pendulum Dynamical System

Human body parts move when they are involved in an activity. In this paper an attempt is made to analyse the motion of the parts in line with the conservation of energy principle. Human body was modelled longitudinally as an inverted Quadruple pendulum. Analytical approach was adopted in analysing the potential and kinetic energies of the systems segments. The findings are consistent with the ones in the literature. Specifically, there is a positive correlation between the height of segments of the system and mechanical energy at the different segments of the system

Lithofacies Analysis and Depositional Environments of the Eocene Nanka Sand as Exposed at Alor and Environs, Southeastern Nigeria: Evidence from Field Study and Granulometric Analysis

The genetic relationship between depositional processes and rock properties provide a potentially powerful tool for interpreting ancient depositional environments. Field study and granulometric analysis have been used to detect the lithofacies and depositional environment of the Eocene Nanka Sand. The field data shows Nanka Sand as medium to coarse grain sand that is loose and unconsolidated, with cross bedded white to yellow sand having intercalation of silty sand and clay with bands of fine grained sandstone and sandy clay on top. The granulometric study shows Nanka Sand to be coarse to medium grain and negatively skewed. Sorting is moderately well sorted to poorly sorted, and kurtosis is leptokurtic. The frequency histogram showed both unimodal and bimodal characters. Bivariate results together with linear discrimination functions of the sand samples reveal both shallow agitated marine and fluvial deposits. The paleocurrent shows bimodal - bipolar current directions, while the observed sedimentary structures include reactivation surfaces, clay drapes, flaser and wavy beddings, burrows of Skolithos and Ophiomorpha, with herringbone and planar cross beds, indicative of tidally influenced environment. Three distinct lithofacies observed were heterolithic, cross bedded sand facies, channel sand facies, and clay stone facies, and these has allowed the depositional environment of the Eocene Nanka Sand to be interpreted as a tide dominated estuaries characterized by tidally influenced fluvial to mixed energy environment. Keywords: Granulometric, Lithofacies, Heteroliths, Tides, Paleocurrent, Ichnofacies

Pulmonary Hypertension in Systemic Sclerosis

The main cause of death in systemic sclerosis is interstitial lung disease, followed by pulmonary hypertension (PH). Pulmonary hypertension is the result of microvasculopathy which is caused by a disrupted healing process of endothelin damage and is featured by vasoconstriction, proliferation of arterial wall, inflammation, and fibrosis. Reclassification of pulmonary hypertension has led to five distinctive groups. In systemic sclerosis, patients may suffer from pulmonary artery hypertension (PAH, group 1), pulmonary hypertension due to interstitial lung disease (group 3), cardiac disease (group 2), and/or thromboembolic pulmonary hypertension (group 4). Patients endure declining performance during exercise, but symptoms may be variable and nonspecific. Diagnosis is made by right heart catheterization. To select patients for this invasive procedure, several screening tools are discussed, including N-terminal pro-brain natriuretic peptide levels, uric acid levels, spirometry and diffusing capacity for carbon monoxide (DCLO), echocardiography (ECG), and the DETECT algorithm. Depending on features such as disease duration, presence of anti-centromere antibodies, and DCLO, three different flow charts for screening are presented. Based on pathophysiology, several medical treatments have been developed like prostanoids, endothelin receptor antagonists, phosphodiesterase-5 inhibitors, and stimulation of the nitric oxide pathway. Combination therapy as well as lung transplantation and supportive therapy is discussed