PREPARATION OF BIOLOGICAL MATERIAL FOR RADIOAUTOGRAPHIC STUDIES OF INTERMEDIARY METABOLISM

The intermediary metabolism of many kinds of biological material may be studied by supplying the tissue with radioactive substrates and analyzing the reaction products by paper chromatography and radioautography. The preparation of the tissue in a form suitable for such study frequently presents difficulty. Several experimental approaches to this problem are discussed which have been applied successfully to the metabolism of tissues from widely differing organisms. (auth

Photolytic Hazes in the Atmosphere of 51 Eri b

We use a 1D model to address photochemistry and possible haze formation in the irradiated warm Jupiter, 51 Eridani b. The intended focus was to be carbon, but sulfur photochemistry turns out to be important. The case for organic photochemical hazes is intriguing but falls short of being compelling. If organic hazes form, they are likeliest to do so if vertical mixing in 51 Eri b is weaker than in Jupiter, and they would be found below the altitudes where methane and water are photolyzed. The more novel result is that photochemistry turns H$_2$S into elemental sulfur, here treated as S$_8$. In the cooler models, S$_8$ is predicted to condense in optically thick clouds of solid sulfur particles, whilst in the warmer models S$_8$ remains a vapor along with several other sulfur allotropes that are both visually striking and potentially observable. For 51 Eri b, the division between models with and without condensed sulfur is at an effective temperature of 700 K, which is within error its actual effective temperature; the local temperature where sulfur condenses is between 280 and 320 K. The sulfur photochemistry we have discussed is quite general and ought to be found in a wide variety of worlds over a broad temperature range, both colder and hotter than the 650-750 K range studied here, and we show that products of sulfur photochemistry will be nearly as abundant on planets where the UV irradiation is orders of magnitude weaker than it is on 51 Eri b.Comment: 24 pages including 11 figures and a tabl

Perspectives for Positron Emission Tomography with RPCs

In this study we address the feasibility and main properties of a positron emission tomograph (PET) based on RPCs. The concept, making use of the converter-plate principle, takes advantage of the intrinsic layered structure of RPCs and its simple and economic construction. The extremely good time and position resolutions of RPCs also allow the TOF-PET imaging technique to be considered. Monte-Carlo simulations, supported by experimental data, are presented and the main advantages and drawbacks for applications of potential interest are discussed.Comment: Presented at "RPC2001-VI Workshop on Resistive Plate Chambers and Related Detectors", Coimbra, Portugal, 26-27 November 2001 (5 pages

Role Conflicts Experienced by Male College Varsity Football Players

The purpose of this study was to examine the extent to which male college football players experienced role conflict. The possible interrelationship between race, eligibility classification, and experienced conflict as measured by the seven interpretable conflict variables (competition, psychological pressure, time, demand pressure. family, race and sport improvement needs) also was studied. A 67-item questionnaire developed by the authors was completed by 72 football students (76% on full scholarship, 24% walk-on) at a large Midwestern University at the end of the 1986 season about the extent and source of experienced role conflict over time, plus 32 demographic items. The results were submitted to factor analysis. The variables were studied with ANOVA and MANOVA. In general for this sample it appeared that football players did not experience a great deal of role conflict. It is theorized that this may be due in part to the fact that student athletes who participated in football at this university were provided with many support services. An analysis of the data showed that factors related to competition, psychologicai pressure and time produced the greatest amount of conflict for football players. These findings suggest that black student athletes who attend predominantly white institutions may have a much more difficult time coping with the demands of sports and academics than white athletes. Increasing the number of black support staff personnel would seem logical. The results of this study imply that an increase in black coaches, university, and athletic staff personnel might assist in remediating the amount of conflict felt by black student athletes. It was found that athletes differed significantly only in terms of the factors time and competition. It was found that freshmen and sophomores (underclassmen) experienced more conflict in relation to time variables than juniors and seniors (upperclassmen)

Activation of adenosine A2A receptors induces TrkB translocation and increases BDNF-mediated phospho-TrkB localization in lipid rafts : implications for neuromodulation

Copyright © 2010 the authorsBrain-derived neurotrophic factor (BDNF) signaling is critical for neuronal development and transmission. Recruitment of TrkB receptors to lipid rafts has been hown to be necessary for the activation of specific signaling pathways and modulation of neurotransmitter release by BDNF. Since TrkB receptors are known to be modulated by adenosine A2A receptor activation, we hypothesized that activation of A2A receptors could influence TrkB receptor localization among different membrane microdomains. We found that adenosine A2A receptor agonists increased the levels of TrkB receptors in the lipid raft fraction of cortical membranes and potentiated BDNF-induced augmentation of phosphorylated TrkB levels in lipid rafts. Blockade of the clathrin-mediated endocytosis with monodansylcadaverine(100µM) did not modify the effects of theA2A receptor agonists but significantly impairedBDNFeffects on TrkB recruitment to lipid rafts. The effect of A2A receptor activation in TrkB localization was mimicked by 5 µM forskolin, an adenylyl cyclase activator. Also, it was blocked by the PKA inhibitors Rp-cAMPs and PKI-(14 –22), and by the Src-family kinase inhibitor PP2. Moreover, removal of endogenous adenosine or disruption of lipid rafts reduced BDNF stimulatory effects on glutamate release from cortical synaptosomes. Lipid raft integrity was also required for the effects of BDNF on hippocampal long-term potentiation at CA1 synapses. Our data demonstrate, for the first time, a BDNF-independent recruitment of TrkB receptors to lipid rafts induced by activation of adenosine A2A receptors, with functional consequences for TrkB phosphorylation and BDNF-induced modulation of neurotransmitter release and hippocampal plasticity.Supported by Fundacão para a Ciência e a Tecnologia (SFRH/BD/21374/2005 for N.A.L., SFRH/BD/21359/2005 for V.C.S., and SFRH/BPD/11528/2002 for D.B.P.) and by the European Union [European Cooperation in Science and Technology (COST) COST B30 concerted action, Neural Regeneration and Plasticity (NEREPLAS)]

Mathematical Projections of Air Pollutants Effects over Niger Delta Region Using Remotely Sensed Satellite Data

Air pollution due gas–flaring is a major concern in the Niger-Delta region of Nigeria. The short and long term effect of the massive air pollution on the life form within the area requires urgent attention because of the health implication. This research examines the impact of air pollutants in Niger-Delta region using remotely sensed satellite data. The satellite data set was obtained from CALIPSO, MODIS and ARIS. A mathematical software (MATLAB) was used to analyse the results. For Sulphur dioxide (SO2), Uyo had the highest rate of pollution (0.67DU), then Yenegoa (0.66DU), Benin (0.64DU), Asaba (0.60DU), Port Harcourt (0.58DU), Calabar (0.55DU) respectively. For Carbon dioxide (CO2), Yenegoa was the most polluted with (382.01ppmv), Port Harcourt, Calabar and Uyo all had (381.99ppmv) then Benin (381.77ppmv) and Asaba (381.53ppmv) respectively. For Nitrogen dioxide (NO2), Port Harcourt had the highest mean value with (54.65mol/cm2), Asaba (51.05mol/cm2), Uyo (49.08mol/cm2),Calabar (47.84mol/cm2), Yenagoa (46.73mol/cm2), Benin (43.22mol/cm2) respectively. For Methane (CH4), the stations with the highest rate of pollution were Port Harcourt, Yenagoa and Uyo with (3.86E+19mol/cm2), Benin and Asaba had (3.8E+19mol/cm2) while Calabar (3.76E+19mol/cm2). Mathematical projections were made to capture the dilemma- people in this region might encounter in the nearest future

Outdoor Air Pollution in Kumbo Cameroun

In this paper, the air quality of Kumbo-Cameroon was investigated. Aerosol optical depth (AOD) dataset for fourteen years was obtained from the Multi-angle Imaging Spectro-Radiometer (MISR). The raw dataset was processed and treated. The aerosol loading over the research location was obtained from the AOD datasets. It was observed that the main pollution is from anthropogenic emission and Sahara dust. The current aerosol loading over Kumbo is high and it is gradually reducing by 1.81%, though not significantly. The data presented is essential for ground measurement over the research area

Modeling of magnetic loop antenna for an improved rockets/spacecraft communication operation

the magnetic loop antenna (MLA) is a compact hf antennas used transmitting signals within a fairly long distance. Its shape and size had metaphorsize from the usual analogue to a digital device-which is now used for experiments in space. In this paper, the resolution of the bearing angle errors of the antennas on a rocket or spacecraft was proposed to enhance improved application in signal transmission. A new concept was introduced -angular displacement theory which was used to mitigate fading in multipath propagation especially from Rocket or spacecraft orbit

A case study: Application of energy and exergy analysis for enhancing the process efficiency of a three stage propane pre-cooling cycle of the cascade LNG process

The propane pre-cooling cycle has been widely used in most LNG plants as the first cooling cycle in the natural gas liquefaction process. As LNG plants consume high amounts of energy, enhancements in the process design and plant operation will minimize the overall energy consumption of the plant. The aim of this study is to enhance the process efficiency of a three stage propane pre-cooling cycle of the Cascade LNG process for the large-scale LNG train by determining the optimal operating conditions of the propane evaporator that will minimize the overall energy consumption. Energy and exergy analysis methods are adopted to evaluate the process efficiency of the propane pre-cooling cycle. Six case studies were presented to determine the optimal operating conditions of the propane evaporator that gives maximum energy reduction. The propane pre-cooling cycle is modelled and simulated using Aspen HYSYS with detailed thermodynamic information obtained to calculate the exergy loss. The results of the energy and exergy analysis indicate that Case 6 gives the highest coefficient of performance (COP) and the maximum exergy efficiency compared to the baseline case, which are 15.51% and 18.76% respectively. The results indicate that by reducing the cooling duty at the intermediate stages of propane evaporator about 13.5% energy saving can be achieved compared to the baseline case