Computerized analytical technique for design and analysis of a Sabatier reactor subsystem Final engineering report

Mathematical model for computerized evaluation of Sabatier reaction kinetics in oxygen recovery from carbon dioxid

H(II) centers in natural silica under repeated UV laser irradiations

We investigated the kinetics of H(II) centers (=Ge'-H) in natural silica under repeated 266nm UV irradiations performed by a Nd:YAG pulsed laser. UV photons temporarily destroy these paramagnetic defects, their reduction being complete within 250 pulses. After re-irradiation, H(II) centers grow again, and the observed recovery kinetics depends on the irradiation dose; multiple 2000 pulses re-irradiations induce the same post-irradiation kinetics of H(II) centers after each exposure cycle. The analysis of these effects allows us to achieve a deeper understanding of the dynamics of the centers during and after laser irradiation.Comment: Submitted to Journal of Non Crystalline Solid

Influence of recovery intensity on oxygen demand and repeated sprint performance

AIM: This study aimed to determine effects of recovery intensity (passive, 20, 30 and 40%V̇ O2peak) on oxygen uptake kinetics, performance and blood lactate accumulation during repeated sprints. METHODS: 7 moderately-trained male participants (V̇O2peak: 48.1 ± 5.1 ml·kg-1·min-1) performed 4 x 30-s repeated Wingate tests on 4 separate occasions. RESULTS: Recovery of V̇ O2 between sprints was prolonged with recovery intensity (time required to reach 50% V̇O2peak: Passive: 50 ± 9; 20%: 81 ± 17; 30%: 130 ± 43; 40%: 188 ± 62 sec, P<0.001), while V̇O2-to-sprint work ratio was mainly increased by the higher intensities (Passive: 138 ± 17; 20%: 149 ± 14; 30%: 159 ± 15; 40%: 158 ± 17 ml·min-1·kJ-1, P=0.001). The decline in peak power tended to be greater in the higher intensity conditions during sprint 2 (Passive: 7.4 ± 5.4; 20%: 5.8 ± 7.9; 30%: 12.7 ± 7.4; 40%: 12.7 ± 5.5%, P=0.052), whereas average power was less decreased with recovery intensity during sprint 4 (Passive: 22.4 ± 8.9; 20%: 19.9 ± 6.1; 30%: 18.4 ± 7.3; 40%: 16.6 ± 6.2%, P=0.036). Blood lactate was not different with recovery intensity (P=0.251). CONCLUSION: The present study demonstrated that while the higher recovery intensities induce prolonged oxygen recovery and impaired peak power restoration during the initial sprints, those intensities provide a greater aerobic contribution to sprint performance, resulting in better power maintenance during the latter sprints

Reduced Toxicity Conditioning with Busulfan, Fludarabine, Alemtuzumab and Allogeneic Stem Cell Transplantation From HLA-Matched Sibling Donors in Children with High Risk Sickle Cell Disease Results in Long Term Donor Chimerism and Low Incidence of aGVHD

Purpose It is still equivocal whether oxygen uptake recovery kinetics are limited by oxygen delivery and can be improved by supplementary oxygen. The present study aimed to investigate whether measurements of muscle and pulmonary oxygen uptake kinetics can be used to assess oxygen delivery limitations in healthy subjects. Methods Sixteen healthy young adults performed three sub-maximal exercise tests (6 min at 40% Wmax) under hypoxic (14%O2), normoxic (21%O2) and hyperoxic (35%O2) conditions on separate days in randomized order. Both Pulmonary VO2 and near infra red spectroscopy (NIRS) based Tissue Saturation Index (TSI) offset kinetics were calculated using mono-exponential curve fitting models. Results Time constant τ of VO2 offset kinetics under hypoxic (44.9 ± 7.3s) conditions were significantly larger than τ of the offset kinetics under normoxia (37.9 ± 8.2s, p = 0.02) and hyperoxia (37±6s, p = 0.04). TSI mean response time (MRT) of the offset kinetics under hypoxic conditions (25.5 ± 13s) was significantly slower than under normoxic (15 ± 7.7, p = 0.007) and hyperoxic (13 ± 7.3, p = 0.008) conditions. Conclusion The present study shows that there was no improvement in the oxygen uptake and muscle oxygenation recovery kinetics in healthy subjects under hyperoxic conditions. Slower TSI and VO2 recovery kinetics under hypoxic conditions indicate that both NIRS and spiro-ergometry are appropriate non-invasive measurement tools to assess the physiological response of a healthy individual to hypoxic exercise

Determining kinetic constants and transport efficiencies at membrane interfaces to optimize the removal/recovery of Cu(II) through lulk liquid membranes containing benzoylacetone as carrier

The removal, separation, and enrichment of heavy metals in aqueous solutions has become a prime concern over the last few decades because of both their adverse effects on the ecosystem and living organisms and their valuable resource character. This paper describes a study to optimize the simultaneous removal/ recovery of Cu(II) from aqueous solutions by bulk liquid membranes, through a facilitated countertransport mechanism using benzoylacetone as a mobile carrier and hydrochloric acid as a stripping agent (protons as counter ions), by analyzing the effect of different operational variables (carrier concentration in membrane phase, stripping agent concentration in product phase, stirring rate, and membrane phase volume) on the removal/recovery kinetics constants and on the transport efficiencies through the feed/membrane and membrane/product interfaces.We would like to thank Mr. A. Guzmán and Mr. J.A. López for manufacturing the experimental cell

Differences in protein mobility between pioneer versus follower growth cones

Navigating growth cones need to integrate, process and respond to guidance signals, requiring dynamic information transfer within and between different compartments. Studies have shown that, faced with different navigation challenges, growth cones display dynamic changes in growth kinetics and morphologies. However, it remains unknown whether these are paralleled by differences in their internal molecular dynamics. To examine whether there are protein mobility differences during guidance, we developed multiphoton fluorescence recovery after photobleaching methods to determine molecular diffusion rates in pathfinding growth cones in vivo. Actively navigating growth cones (leaders) have consistently longer recovery times than growth cones that are fasciculated and less actively navigating (followers). Pharmacological perturbations of the cytoskeleton point to actin as the primary modulator of diffusion in differently behaving growth cones. This approach provides a powerful means to quantify mobility of specific proteins in neurons in vivo and reveals that diffusion is important during axon navigation

A model of heart rate kinetics in response to exercise

We present a mathematical model, in the form of two coupled ordinary differential equations, for the heart rate kinetics in response to exercise. Our heart rate model is an adaptation of the model of oxygen uptake kinetics of Stirling: a physiological justification for this adaptation, as well as the physiological basis of our heart rate model is provided. We also present the optimal fit of the heart rate model to a set of raw un averaged data for multiple constant intensity exercises for an individual at a particular level of fitness

Non affine deformations and shape recovery in solids undergoing martensitic transformations

We study, using molecular dynamics simulations, the kinetics of shape recovery in a model solid undergoing transformations from square to a general rhombic lattice, the triangular lattice being included as a special case. We determine the necessary and sufficient conditions for such shape recovery in terms of the nature and dynamics of transient and localized {\em non-affine zones} which inevitably accompany the transformation.Comment: 8 pages, 4 figures, higher resolution figures available on reques

Functional modulation of the transient outward current Ito by KCNE beta-subunits and regional distribution in human non-failing and failing hearts

Objectives: The function of Kv4.3 (KCND3) channels, which underlie the transient outward current I,, in human heart, can be modulated by several accessory subunits such as KChIP2 and KCNE1-KCNE5. Here we aimed to determine the regional expression of Kv4.3, KChIP2, and KCNE mRNAs in non-failing and failing human hearts and to investigate the functional consequences of subunit coexpression in heterologous expression systems. Methods: We quantified mRNA levels for two Kv4.3 isoforms, Kv4.3-S and Kv4.3-L, and for KChIP2 as well as KCNE1-KCNE5 with real-time RT-PCR. We also studied the effects of KCNEs on Kv4.3 + KChIP2 current characteristics in CHO cells with the whole-cell voltage-clamp method. Results: In non-failing hearts, low expression was found for KCNE1, KCNE3, and KCNE5, three times higher expression for KCNE2, and 60 times higher for KCNE4. Transmural gradients were detected only for KChIP2 in left and right ventricles. Compared to non-failing tissue, failing hearts showed higher expression of Kv4.3-L and KCNE1 and lower of Kv4.3-S, KChIP2, KCNE4, and KCNE5. In CHO cells, Kv4.3 + KChIP2 currents were differentially modified by co-expressed KCNEs: time constants of inactivation were shorter with KCNE1 and KCNE3-5 while time-to-peak was decreased, and V-0.5 of steady-state inactivation was shifted to more negative potentials by all KCNE subunits. Importantly, KCNE2 induced a unique and prominent 'overshoot' of peak current during recovery from inactivation similar to that described for human I-to while other KCNE subunits induced little (KCNE4,5) or no overshoot. Conclusions: All KCNEs are expressed in the human heart at the transcript level. Compared to It. in native human myocytes, none of the combination of KChIP2 and KCNE produced an ideal congruency in current characteristics, suggesting that additional factors contribute to the regulation of the native I-to channel